[PATCH v3 0/4] Add STM32 MDMA driver

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* [PATCH v3 0/4] Add STM32 MDMA driver
@ 2017-07-26  9:48 ` Pierre-Yves MORDRET
  0 siblings, 0 replies; 26+ messages in thread
From: Pierre-Yves MORDRET @ 2017-07-26  9:48 UTC (permalink / raw)
  To: Vinod Koul, Rob Herring, Mark Rutland, Maxime Coquelin,
	Alexandre Torgue, Russell King, Dan Williams,
	M'boumba Cedric Madianga, Fabrice GASNIER, Herbert Xu,
	Fabien DESSENNE, Amelie Delaunay, Pierre-Yves MORDRET, dmaengine,
	devicetree, linux-arm-kernel, linux-kernel

This patchset adds support for the STM32 MDMA controller.
The Master Direct memory access (MDMA) provides high-speed data transfer
between memory and memory or between peripherals and memory.
Contrary to STM32 DMA, the STM32 MDMA controller supports hardware LLI and
uses a larger integrated FIFO (128 vs 16 bytes)
---
  Version history:
     v3:
         * Update header template
         * Unsigned expression compared with zero
         * Rework stm32_mdma_get_max_width
         * moved to src/dst case where they are used in set_xfer
         * Change of_property_* with device_property_*
         * Add dev_warn whether default value is used
         * Indentation
         * Add MODULE_*
     v2:
         * change compatible into st,stm32h7-mdma to be more SoC specific
         * Add MDMA support in DT for H7
         * Add MDMA support in STM32 defconfig
---
Pierre-Yves MORDRET (4):
  dt-bindings: Document the STM32 MDMA bindings
  dmaengine: Add STM32 MDMA driver
  ARM: dts: stm32: Add MDMA support for STM32H743 SoC
  ARM: configs: stm32: Add MDMA support in STM32 defconfig

 .../devicetree/bindings/dma/stm32-mdma.txt         |   94 ++
 arch/arm/boot/dts/stm32h743.dtsi                   |   10 +
 arch/arm/configs/stm32_defconfig                   |    1 +
 drivers/dma/Kconfig                                |   12 +
 drivers/dma/Makefile                               |    1 +
 drivers/dma/stm32-mdma.c                           | 1565 ++++++++++++++++++++
 6 files changed, 1683 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/stm32-mdma.txt
 create mode 100644 drivers/dma/stm32-mdma.c

-- 
2.7.4

^ permalink raw reply	[flat|nested] 26+ messages in thread

* [PATCH v3 0/4] Add STM32 MDMA driver
@ 2017-07-26  9:48 ` Pierre-Yves MORDRET
  0 siblings, 0 replies; 26+ messages in thread
From: Pierre-Yves MORDRET @ 2017-07-26  9:48 UTC (permalink / raw)
  To: Vinod Koul, Rob Herring, Mark Rutland, Maxime Coquelin,
	Alexandre Torgue, Russell King, Dan Williams,
	M'boumba Cedric Madianga, Fabrice GASNIER, Herbert Xu,
	Fabien DESSENNE, Amelie Delaunay, Pierre-Yves MORDRET, dmaengine,
	devicetree, linux-arm-kernel, linux-kernel

This patchset adds support for the STM32 MDMA controller.
The Master Direct memory access (MDMA) provides high-speed data transfer
between memory and memory or between peripherals and memory.
Contrary to STM32 DMA, the STM32 MDMA controller supports hardware LLI and
uses a larger integrated FIFO (128 vs 16 bytes)
---
  Version history:
     v3:
         * Update header template
         * Unsigned expression compared with zero
         * Rework stm32_mdma_get_max_width
         * moved to src/dst case where they are used in set_xfer
         * Change of_property_* with device_property_*
         * Add dev_warn whether default value is used
         * Indentation
         * Add MODULE_*
     v2:
         * change compatible into st,stm32h7-mdma to be more SoC specific
         * Add MDMA support in DT for H7
         * Add MDMA support in STM32 defconfig
---
Pierre-Yves MORDRET (4):
  dt-bindings: Document the STM32 MDMA bindings
  dmaengine: Add STM32 MDMA driver
  ARM: dts: stm32: Add MDMA support for STM32H743 SoC
  ARM: configs: stm32: Add MDMA support in STM32 defconfig

 .../devicetree/bindings/dma/stm32-mdma.txt         |   94 ++
 arch/arm/boot/dts/stm32h743.dtsi                   |   10 +
 arch/arm/configs/stm32_defconfig                   |    1 +
 drivers/dma/Kconfig                                |   12 +
 drivers/dma/Makefile                               |    1 +
 drivers/dma/stm32-mdma.c                           | 1565 ++++++++++++++++++++
 6 files changed, 1683 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/stm32-mdma.txt
 create mode 100644 drivers/dma/stm32-mdma.c

-- 
2.7.4

^ permalink raw reply	[flat|nested] 26+ messages in thread

* [PATCH v3 0/4] Add STM32 MDMA driver
@ 2017-07-26  9:48 ` Pierre-Yves MORDRET
  0 siblings, 0 replies; 26+ messages in thread
From: Pierre-Yves MORDRET @ 2017-07-26  9:48 UTC (permalink / raw)
  To: linux-arm-kernel

This patchset adds support for the STM32 MDMA controller.
The Master Direct memory access (MDMA) provides high-speed data transfer
between memory and memory or between peripherals and memory.
Contrary to STM32 DMA, the STM32 MDMA controller supports hardware LLI and
uses a larger integrated FIFO (128 vs 16 bytes)
---
  Version history:
     v3:
         * Update header template
         * Unsigned expression compared with zero
         * Rework stm32_mdma_get_max_width
         * moved to src/dst case where they are used in set_xfer
         * Change of_property_* with device_property_*
         * Add dev_warn whether default value is used
         * Indentation
         * Add MODULE_*
     v2:
         * change compatible into st,stm32h7-mdma to be more SoC specific
         * Add MDMA support in DT for H7
         * Add MDMA support in STM32 defconfig
---
Pierre-Yves MORDRET (4):
  dt-bindings: Document the STM32 MDMA bindings
  dmaengine: Add STM32 MDMA driver
  ARM: dts: stm32: Add MDMA support for STM32H743 SoC
  ARM: configs: stm32: Add MDMA support in STM32 defconfig

 .../devicetree/bindings/dma/stm32-mdma.txt         |   94 ++
 arch/arm/boot/dts/stm32h743.dtsi                   |   10 +
 arch/arm/configs/stm32_defconfig                   |    1 +
 drivers/dma/Kconfig                                |   12 +
 drivers/dma/Makefile                               |    1 +
 drivers/dma/stm32-mdma.c                           | 1565 ++++++++++++++++++++
 6 files changed, 1683 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/stm32-mdma.txt
 create mode 100644 drivers/dma/stm32-mdma.c

-- 
2.7.4

^ permalink raw reply	[flat|nested] 26+ messages in thread

* [PATCH v3 1/4] dt-bindings: Document the STM32 MDMA bindings
@ 2017-07-26  9:48   ` Pierre-Yves MORDRET
  0 siblings, 0 replies; 26+ messages in thread
From: Pierre-Yves MORDRET @ 2017-07-26  9:48 UTC (permalink / raw)
  To: Vinod Koul, Rob Herring, Mark Rutland, Maxime Coquelin,
	Alexandre Torgue, Russell King, Dan Williams,
	M'boumba Cedric Madianga, Fabrice GASNIER, Herbert Xu,
	Fabien DESSENNE, Amelie Delaunay, Pierre-Yves MORDRET, dmaengine,
	devicetree, linux-arm-kernel, linux-kernel

This patch adds documentation of device tree bindings for the STM32 MDMA
controller.

Signed-off-by: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
Acked-by: Rob Herring <robh@kernel.org>
---
  Version history:
     v3:
         * None
     v2:
         * change compatible into st,stm32h7-mdma to be more SoC specific
---
---
 .../devicetree/bindings/dma/stm32-mdma.txt         | 94 ++++++++++++++++++++++
 1 file changed, 94 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/stm32-mdma.txt

diff --git a/Documentation/devicetree/bindings/dma/stm32-mdma.txt b/Documentation/devicetree/bindings/dma/stm32-mdma.txt
new file mode 100644
index 0000000..d18772d
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/stm32-mdma.txt
@@ -0,0 +1,94 @@
+* STMicroelectronics STM32 MDMA controller
+
+The STM32 MDMA is a general-purpose direct memory access controller capable of
+supporting 64 independent DMA channels with 256 HW requests.
+
+Required properties:
+- compatible: Should be "st,stm32h7-mdma"
+- reg: Should contain MDMA registers location and length. This should include
+  all of the per-channel registers.
+- interrupts: Should contain the MDMA interrupt.
+- clocks: Should contain the input clock of the DMA instance.
+- resets: Reference to a reset controller asserting the DMA controller.
+- #dma-cells : Must be <5>. See DMA client paragraph for more details.
+
+Optional properties:
+- dma-channels: Number of DMA channels supported by the controller.
+- dma-requests: Number of DMA request signals supported by the controller.
+- st,ahb-addr-masks: Array of u32 mask to list memory devices addressed via
+  AHB bus.
+
+Example:
+
+	mdma1: dma@52000000 {
+		compatible = "st,stm32h7-mdma";
+		reg = <0x52000000 0x1000>;
+		interrupts = <122>;
+		clocks = <&timer_clk>;
+		resets = <&rcc 992>;
+		#dma-cells = <5>;
+		dma-channels = <16>;
+		dma-requests = <32>;
+		st,ahb-addr-masks = <0x20000000>, <0x00000000>;
+	};
+
+* DMA client
+
+DMA clients connected to the STM32 MDMA controller must use the format
+described in the dma.txt file, using a five-cell specifier for each channel:
+a phandle to the MDMA controller plus the following five integer cells:
+
+1. The request line number
+2. The priority level
+	0x00: Low
+	0x01: Medium
+	0x10: High
+	0x11: Very high
+3. A 32bit mask specifying the DMA channel configuration
+ -bit 0-1: Source increment mode
+	0x00: Source address pointer is fixed
+	0x10: Source address pointer is incremented after each data transfer
+	0x11: Source address pointer is decremented after each data transfer
+ -bit 2-3: Destination increment mode
+	0x00: Destination address pointer is fixed
+	0x10: Destination address pointer is incremented after each data
+	transfer
+	0x11: Destination address pointer is decremented after each data
+	transfer
+ -bit 8-9: Source increment offset size
+	0x00: byte (8bit)
+	0x01: half-word (16bit)
+	0x10: word (32bit)
+	0x11: double-word (64bit)
+ -bit 10-11: Destination increment offset size
+	0x00: byte (8bit)
+	0x01: half-word (16bit)
+	0x10: word (32bit)
+	0x11: double-word (64bit)
+-bit 25-18: The number of bytes to be transferred in a single transfer
+	(min = 1 byte, max = 128 bytes)
+-bit 29:28: Trigger Mode
+	0x00: Each MDMA request triggers a buffer transfer (max 128 bytes)
+	0x01: Each MDMA request triggers a block transfer (max 64K bytes)
+	0x10: Each MDMA request triggers a repeated block transfer
+	0x11: Each MDMA request triggers a linked list transfer
+4. A 32bit value specifying the register to be used to acknowledge the request
+   if no HW ack signal is used by the MDMA client
+5. A 32bit mask specifying the value to be written to acknowledge the request
+   if no HW ack signal is used by the MDMA client
+
+Example:
+
+	i2c4: i2c@5c002000 {
+		compatible = "st,stm32f7-i2c";
+		reg = <0x5c002000 0x400>;
+		interrupts = <95>,
+			     <96>;
+		clocks = <&timer_clk>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+		dmas = <&mdma1 36 0x0 0x40008 0x0 0x0>,
+		       <&mdma1 37 0x0 0x40002 0x0 0x0>;
+		dma-names = "rx", "tx";
+		status = "disabled";
+	};
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 26+ messages in thread

* [PATCH v3 1/4] dt-bindings: Document the STM32 MDMA bindings
@ 2017-07-26  9:48   ` Pierre-Yves MORDRET
  0 siblings, 0 replies; 26+ messages in thread
From: Pierre-Yves MORDRET @ 2017-07-26  9:48 UTC (permalink / raw)
  To: Vinod Koul, Rob Herring, Mark Rutland, Maxime Coquelin,
	Alexandre Torgue, Russell King, Dan Williams,
	M'boumba Cedric Madianga, Fabrice GASNIER, Herbert Xu,
	Fabien DESSENNE, Amelie Delaunay, Pierre-Yves MORDRET,
	dmaengine-u79uwXL29TY76Z2rM5mHXA,
	devicetree-u79uwXL29TY76Z2rM5mHXA,
	linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA

This patch adds documentation of device tree bindings for the STM32 MDMA
controller.

Signed-off-by: M'boumba Cedric Madianga <cedric.madianga-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret-qxv4g6HH51o@public.gmane.org>
Acked-by: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
  Version history:
     v3:
         * None
     v2:
         * change compatible into st,stm32h7-mdma to be more SoC specific
---
---
 .../devicetree/bindings/dma/stm32-mdma.txt         | 94 ++++++++++++++++++++++
 1 file changed, 94 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/stm32-mdma.txt

diff --git a/Documentation/devicetree/bindings/dma/stm32-mdma.txt b/Documentation/devicetree/bindings/dma/stm32-mdma.txt
new file mode 100644
index 0000000..d18772d
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/stm32-mdma.txt
@@ -0,0 +1,94 @@
+* STMicroelectronics STM32 MDMA controller
+
+The STM32 MDMA is a general-purpose direct memory access controller capable of
+supporting 64 independent DMA channels with 256 HW requests.
+
+Required properties:
+- compatible: Should be "st,stm32h7-mdma"
+- reg: Should contain MDMA registers location and length. This should include
+  all of the per-channel registers.
+- interrupts: Should contain the MDMA interrupt.
+- clocks: Should contain the input clock of the DMA instance.
+- resets: Reference to a reset controller asserting the DMA controller.
+- #dma-cells : Must be <5>. See DMA client paragraph for more details.
+
+Optional properties:
+- dma-channels: Number of DMA channels supported by the controller.
+- dma-requests: Number of DMA request signals supported by the controller.
+- st,ahb-addr-masks: Array of u32 mask to list memory devices addressed via
+  AHB bus.
+
+Example:
+
+	mdma1: dma@52000000 {
+		compatible = "st,stm32h7-mdma";
+		reg = <0x52000000 0x1000>;
+		interrupts = <122>;
+		clocks = <&timer_clk>;
+		resets = <&rcc 992>;
+		#dma-cells = <5>;
+		dma-channels = <16>;
+		dma-requests = <32>;
+		st,ahb-addr-masks = <0x20000000>, <0x00000000>;
+	};
+
+* DMA client
+
+DMA clients connected to the STM32 MDMA controller must use the format
+described in the dma.txt file, using a five-cell specifier for each channel:
+a phandle to the MDMA controller plus the following five integer cells:
+
+1. The request line number
+2. The priority level
+	0x00: Low
+	0x01: Medium
+	0x10: High
+	0x11: Very high
+3. A 32bit mask specifying the DMA channel configuration
+ -bit 0-1: Source increment mode
+	0x00: Source address pointer is fixed
+	0x10: Source address pointer is incremented after each data transfer
+	0x11: Source address pointer is decremented after each data transfer
+ -bit 2-3: Destination increment mode
+	0x00: Destination address pointer is fixed
+	0x10: Destination address pointer is incremented after each data
+	transfer
+	0x11: Destination address pointer is decremented after each data
+	transfer
+ -bit 8-9: Source increment offset size
+	0x00: byte (8bit)
+	0x01: half-word (16bit)
+	0x10: word (32bit)
+	0x11: double-word (64bit)
+ -bit 10-11: Destination increment offset size
+	0x00: byte (8bit)
+	0x01: half-word (16bit)
+	0x10: word (32bit)
+	0x11: double-word (64bit)
+-bit 25-18: The number of bytes to be transferred in a single transfer
+	(min = 1 byte, max = 128 bytes)
+-bit 29:28: Trigger Mode
+	0x00: Each MDMA request triggers a buffer transfer (max 128 bytes)
+	0x01: Each MDMA request triggers a block transfer (max 64K bytes)
+	0x10: Each MDMA request triggers a repeated block transfer
+	0x11: Each MDMA request triggers a linked list transfer
+4. A 32bit value specifying the register to be used to acknowledge the request
+   if no HW ack signal is used by the MDMA client
+5. A 32bit mask specifying the value to be written to acknowledge the request
+   if no HW ack signal is used by the MDMA client
+
+Example:
+
+	i2c4: i2c@5c002000 {
+		compatible = "st,stm32f7-i2c";
+		reg = <0x5c002000 0x400>;
+		interrupts = <95>,
+			     <96>;
+		clocks = <&timer_clk>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+		dmas = <&mdma1 36 0x0 0x40008 0x0 0x0>,
+		       <&mdma1 37 0x0 0x40002 0x0 0x0>;
+		dma-names = "rx", "tx";
+		status = "disabled";
+	};
-- 
2.7.4

--
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^ permalink raw reply related	[flat|nested] 26+ messages in thread

* [PATCH v3 1/4] dt-bindings: Document the STM32 MDMA bindings
@ 2017-07-26  9:48   ` Pierre-Yves MORDRET
  0 siblings, 0 replies; 26+ messages in thread
From: Pierre-Yves MORDRET @ 2017-07-26  9:48 UTC (permalink / raw)
  To: linux-arm-kernel

This patch adds documentation of device tree bindings for the STM32 MDMA
controller.

Signed-off-by: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
Acked-by: Rob Herring <robh@kernel.org>
---
  Version history:
     v3:
         * None
     v2:
         * change compatible into st,stm32h7-mdma to be more SoC specific
---
---
 .../devicetree/bindings/dma/stm32-mdma.txt         | 94 ++++++++++++++++++++++
 1 file changed, 94 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/stm32-mdma.txt

diff --git a/Documentation/devicetree/bindings/dma/stm32-mdma.txt b/Documentation/devicetree/bindings/dma/stm32-mdma.txt
new file mode 100644
index 0000000..d18772d
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/stm32-mdma.txt
@@ -0,0 +1,94 @@
+* STMicroelectronics STM32 MDMA controller
+
+The STM32 MDMA is a general-purpose direct memory access controller capable of
+supporting 64 independent DMA channels with 256 HW requests.
+
+Required properties:
+- compatible: Should be "st,stm32h7-mdma"
+- reg: Should contain MDMA registers location and length. This should include
+  all of the per-channel registers.
+- interrupts: Should contain the MDMA interrupt.
+- clocks: Should contain the input clock of the DMA instance.
+- resets: Reference to a reset controller asserting the DMA controller.
+- #dma-cells : Must be <5>. See DMA client paragraph for more details.
+
+Optional properties:
+- dma-channels: Number of DMA channels supported by the controller.
+- dma-requests: Number of DMA request signals supported by the controller.
+- st,ahb-addr-masks: Array of u32 mask to list memory devices addressed via
+  AHB bus.
+
+Example:
+
+	mdma1: dma at 52000000 {
+		compatible = "st,stm32h7-mdma";
+		reg = <0x52000000 0x1000>;
+		interrupts = <122>;
+		clocks = <&timer_clk>;
+		resets = <&rcc 992>;
+		#dma-cells = <5>;
+		dma-channels = <16>;
+		dma-requests = <32>;
+		st,ahb-addr-masks = <0x20000000>, <0x00000000>;
+	};
+
+* DMA client
+
+DMA clients connected to the STM32 MDMA controller must use the format
+described in the dma.txt file, using a five-cell specifier for each channel:
+a phandle to the MDMA controller plus the following five integer cells:
+
+1. The request line number
+2. The priority level
+	0x00: Low
+	0x01: Medium
+	0x10: High
+	0x11: Very high
+3. A 32bit mask specifying the DMA channel configuration
+ -bit 0-1: Source increment mode
+	0x00: Source address pointer is fixed
+	0x10: Source address pointer is incremented after each data transfer
+	0x11: Source address pointer is decremented after each data transfer
+ -bit 2-3: Destination increment mode
+	0x00: Destination address pointer is fixed
+	0x10: Destination address pointer is incremented after each data
+	transfer
+	0x11: Destination address pointer is decremented after each data
+	transfer
+ -bit 8-9: Source increment offset size
+	0x00: byte (8bit)
+	0x01: half-word (16bit)
+	0x10: word (32bit)
+	0x11: double-word (64bit)
+ -bit 10-11: Destination increment offset size
+	0x00: byte (8bit)
+	0x01: half-word (16bit)
+	0x10: word (32bit)
+	0x11: double-word (64bit)
+-bit 25-18: The number of bytes to be transferred in a single transfer
+	(min = 1 byte, max = 128 bytes)
+-bit 29:28: Trigger Mode
+	0x00: Each MDMA request triggers a buffer transfer (max 128 bytes)
+	0x01: Each MDMA request triggers a block transfer (max 64K bytes)
+	0x10: Each MDMA request triggers a repeated block transfer
+	0x11: Each MDMA request triggers a linked list transfer
+4. A 32bit value specifying the register to be used to acknowledge the request
+   if no HW ack signal is used by the MDMA client
+5. A 32bit mask specifying the value to be written to acknowledge the request
+   if no HW ack signal is used by the MDMA client
+
+Example:
+
+	i2c4: i2c at 5c002000 {
+		compatible = "st,stm32f7-i2c";
+		reg = <0x5c002000 0x400>;
+		interrupts = <95>,
+			     <96>;
+		clocks = <&timer_clk>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+		dmas = <&mdma1 36 0x0 0x40008 0x0 0x0>,
+		       <&mdma1 37 0x0 0x40002 0x0 0x0>;
+		dma-names = "rx", "tx";
+		status = "disabled";
+	};
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 26+ messages in thread

* [PATCH v3 2/4] dmaengine: Add STM32 MDMA driver
  2017-07-26  9:48 ` Pierre-Yves MORDRET
  (?)
@ 2017-07-26  9:48   ` Pierre-Yves MORDRET
  -1 siblings, 0 replies; 26+ messages in thread
From: Pierre-Yves MORDRET @ 2017-07-26  9:48 UTC (permalink / raw)
  To: Vinod Koul, Rob Herring, Mark Rutland, Maxime Coquelin,
	Alexandre Torgue, Russell King, Dan Williams,
	M'boumba Cedric Madianga, Fabrice GASNIER, Herbert Xu,
	Fabien DESSENNE, Amelie Delaunay, Pierre-Yves MORDRET, dmaengine,
	devicetree, linux-arm-kernel, linux-kernel

This patch adds the driver for the STM32 MDMA controller.

Master Direct memory access (MDMA) is used in order to provide high-speed
data transfer between memory and memory or between peripherals and memory.

MDMA controller provides a master AXI interface for main memory and
peripheral registers access (system access port) and a master AHB
interface only for Cortex-M7 TCM memory access (TCM access port).

MDMA works in conjunction with the standard DMA controllers (DMA1 or DMA2).
It offers up to 64 channels, each dedicated to managing memory access
requests from one of the DMA stream memory buffer or other peripherals
(w/ integrated FIFO).

Signed-off-by: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
---
  Version history:
     v3:
         * Update header template
         * Unsigned expression compared with zero
         * Rework stm32_mdma_get_max_width
         * moved to src/dst case where they are used in set_xfer
         * Change of_property_* with device_property_*
         * Add dev_warn whether default value is used
         * Indentation
         * Add MODULE_*
     v2:
         * change compatible into st,stm32h7-mdma to be more SoC specific
         * optimize some functions
         * functions factorization
         * remove useless code
---
---
 drivers/dma/Kconfig      |   12 +
 drivers/dma/Makefile     |    1 +
 drivers/dma/stm32-mdma.c | 1565 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 1578 insertions(+)
 create mode 100644 drivers/dma/stm32-mdma.c

diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index fadc4d8..36cac16 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -483,6 +483,18 @@ config STM32_DMA
 	  If you have a board based on such a MCU and wish to use DMA say Y
 	  here.
 
+config STM32_MDMA
+	bool "STMicroelectronics STM32 master dma support"
+	depends on ARCH_STM32 || COMPILE_TEST
+	select DMA_ENGINE
+	select DMA_OF
+	select DMA_VIRTUAL_CHANNELS
+	help
+	  Enable support for the on-chip MDMA controller on STMicroelectronics
+	  STM32 platforms.
+	  If you have a board based on STM32 SoC and wish to use the master DMA
+	  say Y here.
+
 config S3C24XX_DMAC
 	bool "Samsung S3C24XX DMA support"
 	depends on ARCH_S3C24XX || COMPILE_TEST
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index f08f8de..b9747ba 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -59,6 +59,7 @@ obj-$(CONFIG_RENESAS_DMA) += sh/
 obj-$(CONFIG_SIRF_DMA) += sirf-dma.o
 obj-$(CONFIG_STE_DMA40) += ste_dma40.o ste_dma40_ll.o
 obj-$(CONFIG_STM32_DMA) += stm32-dma.o
+obj-$(CONFIG_STM32_MDMA) += stm32-mdma.o
 obj-$(CONFIG_S3C24XX_DMAC) += s3c24xx-dma.o
 obj-$(CONFIG_TXX9_DMAC) += txx9dmac.o
 obj-$(CONFIG_TEGRA20_APB_DMA) += tegra20-apb-dma.o
diff --git a/drivers/dma/stm32-mdma.c b/drivers/dma/stm32-mdma.c
new file mode 100644
index 0000000..a5b351b
--- /dev/null
+++ b/drivers/dma/stm32-mdma.c
@@ -0,0 +1,1565 @@
+/*
+ *
+ * Copyright (C) STMicroelectronics SA 2017
+ * Author(s): M'boumba Cedric Madianga <cedric.madianga@gmail.com>
+ *            Pierre-Yves Mordret <pierre-yves.mordret@st.com>
+ *
+ * License terms: GPL V2.0.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+ * details.
+ *
+ * Driver for STM32 MDMA controller
+ *
+ * Inspired by stm32-dma.c and dma-jz4780.c
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmapool.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/iopoll.h>
+#include <linux/jiffies.h>
+#include <linux/list.h>
+#include <linux/log2.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_dma.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+
+#include "virt-dma.h"
+
+#define STM32_MDMA_GISR0		0x0000 /* MDMA Int Status Reg 1 */
+#define STM32_MDMA_GISR1		0x0004 /* MDMA Int Status Reg 2 */
+
+/* MDMA Channel x interrupt/status register */
+#define STM32_MDMA_CISR(x)		(0x40 + 0x40 * (x)) /* x = 0..62 */
+#define STM32_MDMA_CISR_CRQA		BIT(16)
+#define STM32_MDMA_CISR_TCIF		BIT(4)
+#define STM32_MDMA_CISR_BTIF		BIT(3)
+#define STM32_MDMA_CISR_BRTIF		BIT(2)
+#define STM32_MDMA_CISR_CTCIF		BIT(1)
+#define STM32_MDMA_CISR_TEIF		BIT(0)
+
+/* MDMA Channel x interrupt flag clear register */
+#define STM32_MDMA_CIFCR(x)		(0x44 + 0x40 * (x))
+#define STM32_MDMA_CIFCR_CLTCIF		BIT(4)
+#define STM32_MDMA_CIFCR_CBTIF		BIT(3)
+#define STM32_MDMA_CIFCR_CBRTIF		BIT(2)
+#define STM32_MDMA_CIFCR_CCTCIF		BIT(1)
+#define STM32_MDMA_CIFCR_CTEIF		BIT(0)
+#define STM32_MDMA_CIFCR_CLEAR_ALL	(STM32_MDMA_CIFCR_CLTCIF \
+					| STM32_MDMA_CIFCR_CBTIF \
+					| STM32_MDMA_CIFCR_CBRTIF \
+					| STM32_MDMA_CIFCR_CCTCIF \
+					| STM32_MDMA_CIFCR_CTEIF)
+
+/* MDMA Channel x error status register */
+#define STM32_MDMA_CESR(x)		(0x48 + 0x40 * (x))
+#define STM32_MDMA_CESR_BSE		BIT(11)
+#define STM32_MDMA_CESR_ASR		BIT(10)
+#define STM32_MDMA_CESR_TEMD		BIT(9)
+#define STM32_MDMA_CESR_TELD		BIT(8)
+#define STM32_MDMA_CESR_TED		BIT(7)
+#define STM32_MDMA_CESR_TEA_MASK	GENMASK(6, 0)
+
+/* MDMA Channel x control register */
+#define STM32_MDMA_CCR(x)		(0x4C + 0x40 * (x))
+#define STM32_MDMA_CCR_SWRQ		BIT(16)
+#define STM32_MDMA_CCR_WEX		BIT(14)
+#define STM32_MDMA_CCR_HEX		BIT(13)
+#define STM32_MDMA_CCR_BEX		BIT(12)
+#define STM32_MDMA_CCR_PL_MASK		GENMASK(7, 6)
+#define STM32_MDMA_CCR_PL(n)		(((n) & 0x3) << 6)
+#define STM32_MDMA_CCR_TCIE		BIT(5)
+#define STM32_MDMA_CCR_BTIE		BIT(4)
+#define STM32_MDMA_CCR_BRTIE		BIT(3)
+#define STM32_MDMA_CCR_CTCIE		BIT(2)
+#define STM32_MDMA_CCR_TEIE		BIT(1)
+#define STM32_MDMA_CCR_EN		BIT(0)
+#define STM32_MDMA_CCR_IRQ_MASK		(STM32_MDMA_CCR_TCIE \
+					| STM32_MDMA_CCR_BTIE \
+					| STM32_MDMA_CCR_BRTIE \
+					| STM32_MDMA_CCR_CTCIE \
+					| STM32_MDMA_CCR_TEIE)
+
+/* MDMA Channel x transfer configuration register */
+#define STM32_MDMA_CTCR(x)		(0x50 + 0x40 * (x))
+#define STM32_MDMA_CTCR_BWM		BIT(31)
+#define STM32_MDMA_CTCR_SWRM		BIT(30)
+#define STM32_MDMA_CTCR_TRGM_MSK	GENMASK(29, 28)
+#define STM32_MDMA_CTCR_TRGM(n)		(((n) & 0x3) << 28)
+#define STM32_MDMA_CTCR_TRGM_GET(n)	(((n) & STM32_MDMA_CTCR_TRGM_MSK) >> 28)
+#define STM32_MDMA_CTCR_PAM_MASK	GENMASK(27, 26)
+#define STM32_MDMA_CTCR_PAM(n)		(((n) & 0x3) << 26)
+#define STM32_MDMA_CTCR_PKE		BIT(25)
+#define STM32_MDMA_CTCR_TLEN_MSK	GENMASK(24, 18)
+#define STM32_MDMA_CTCR_TLEN(n)		(((n) & 0x7f) << 18)
+#define STM32_MDMA_CTCR_TLEN_GET(n)	(((n) & STM32_MDMA_CTCR_TLEN_MSK) >> 18)
+#define STM32_MDMA_CTCR_LEN2_MSK	GENMASK(25, 18)
+#define STM32_MDMA_CTCR_LEN2(n)	(((n) & 0xff) << 18)
+#define STM32_MDMA_CTCR_LEN2_GET(n)	(((n) & STM32_MDMA_CTCR_LEN2_MSK) >> 18)
+#define STM32_MDMA_CTCR_DBURST_MASK	GENMASK(17, 15)
+#define STM32_MDMA_CTCR_DBURST(n)	(((n) & 0x7) << 15)
+#define STM32_MDMA_CTCR_SBURST_MASK	GENMASK(14, 12)
+#define STM32_MDMA_CTCR_SBURST(n)	(((n) & 0x7) << 12)
+#define STM32_MDMA_CTCR_DINCOS_MASK	GENMASK(11, 10)
+#define STM32_MDMA_CTCR_DINCOS(n)	(((n) & 0x3) << 10)
+#define STM32_MDMA_CTCR_SINCOS_MASK	GENMASK(9, 8)
+#define STM32_MDMA_CTCR_SINCOS(n)	(((n) & 0x3) << 8)
+#define STM32_MDMA_CTCR_DSIZE_MASK	GENMASK(7, 6)
+#define STM32_MDMA_CTCR_DSIZE(n)	(((n) & 0x3) << 6)
+#define STM32_MDMA_CTCR_SSIZE_MASK	GENMASK(5, 4)
+#define STM32_MDMA_CTCR_SSIZE(n)	(((n) & 0x3) << 4)
+#define STM32_MDMA_CTCR_DINC_MASK	GENMASK(3, 2)
+#define STM32_MDMA_CTCR_DINC(n)		(((n) & 0x3) << 2)
+#define STM32_MDMA_CTCR_SINC_MASK	GENMASK(1, 0)
+#define STM32_MDMA_CTCR_SINC(n)		((n) & STM32_MDMA_CTCR_SINC_MASK)
+#define STM32_MDMA_CTCR_CFG_MASK	(STM32_MDMA_CTCR_SINC_MASK \
+					| STM32_MDMA_CTCR_DINC_MASK \
+					| STM32_MDMA_CTCR_SINCOS_MASK \
+					| STM32_MDMA_CTCR_DINCOS_MASK \
+					| STM32_MDMA_CTCR_LEN2_MSK \
+					| STM32_MDMA_CTCR_TRGM_MSK)
+
+/* MDMA Channel x block number of data register */
+#define STM32_MDMA_CBNDTR(x)		(0x54 + 0x40 * (x))
+#define STM32_MDMA_CBNDTR_BRC_MK	GENMASK(31, 20)
+#define STM32_MDMA_CBNDTR_BRC(n)	(((n) & 0xfff) << 20)
+#define STM32_MDMA_CBNDTR_BRC_GET(n)	(((n) & STM32_MDMA_CBNDTR_BRC_MK) >> 20)
+#define STM32_MDMA_CBNDTR_BRDUM		BIT(19)
+#define STM32_MDMA_CBNDTR_BRSUM		BIT(18)
+#define STM32_MDMA_CBNDTR_BNDT_MASK	GENMASK(16, 0)
+#define STM32_MDMA_CBNDTR_BNDT(n)	((n) & STM32_MDMA_CBNDTR_BNDT_MASK)
+
+/* MDMA Channel x source address register */
+#define STM32_MDMA_CSAR(x)		(0x58 + 0x40 * (x))
+
+/* MDMA Channel x destination address register */
+#define STM32_MDMA_CDAR(x)		(0x5C + 0x40 * (x))
+
+/* MDMA Channel x block repeat address update register */
+#define STM32_MDMA_CBRUR(x)		(0x60 + 0x40 * (x))
+#define STM32_MDMA_CBRUR_DUV_MASK	GENMASK(31, 16)
+#define STM32_MDMA_CBRUR_DUV(n)		(((n) & 0xffff) << 16)
+#define STM32_MDMA_CBRUR_SUV_MASK	GENMASK(15, 0)
+#define STM32_MDMA_CBRUR_SUV(n)		((n) & STM32_MDMA_CBRUR_SUV_MASK)
+
+/* MDMA Channel x link address register */
+#define STM32_MDMA_CLAR(x)		(0x64 + 0x40 * (x))
+
+/* MDMA Channel x trigger and bus selection register */
+#define STM32_MDMA_CTBR(x)		(0x68 + 0x40 * (x))
+#define STM32_MDMA_CTBR_DBUS		BIT(17)
+#define STM32_MDMA_CTBR_SBUS		BIT(16)
+#define STM32_MDMA_CTBR_TSEL_MASK	GENMASK(7, 0)
+#define STM32_MDMA_CTBR_TSEL(n)	((n) & STM32_MDMA_CTBR_TSEL_MASK)
+
+/* MDMA Channel x mask address register */
+#define STM32_MDMA_CMAR(x)		(0x70 + 0x40 * (x))
+
+/* MDMA Channel x mask data register */
+#define STM32_MDMA_CMDR(x)		(0x74 + 0x40 * (x))
+
+#define STM32_MDMA_MAX_BUF_LEN		128
+#define STM32_MDMA_MAX_BLOCK_LEN	65536
+#define STM32_MDMA_MAX_CHANNELS		63
+#define STM32_MDMA_MAX_REQUESTS		256
+#define STM32_MDMA_MAX_BURST		128
+#define STM32_MDMA_VERY_HIGH_PRIORITY	0x11
+
+enum stm32_mdma_trigger_mode {
+	STM32_MDMA_BUFFER,
+	STM32_MDMA_BLOCK,
+	STM32_MDMA_BLOCK_REP,
+	STM32_MDMA_LINKED_LIST,
+};
+
+enum stm32_mdma_width {
+	STM32_MDMA_BYTE,
+	STM32_MDMA_HALF_WORD,
+	STM32_MDMA_WORD,
+	STM32_MDMA_DOUBLE_WORD,
+};
+
+enum stm32_mdma_inc_mode {
+	STM32_MDMA_FIXED = 0,
+	STM32_MDMA_INC = 2,
+	STM32_MDMA_DEC = 3,
+};
+
+struct stm32_mdma_chan_config {
+	u32 request;
+	u32 priority_level;
+	u32 transfer_config;
+	u32 mask_addr;
+	u32 mask_data;
+};
+
+struct stm32_mdma_hwdesc {
+	u32 ctcr;
+	u32 cbndtr;
+	u32 csar;
+	u32 cdar;
+	u32 cbrur;
+	u32 clar;
+	u32 ctbr;
+	u32 dummy;
+	u32 cmar;
+	u32 cmdr;
+} __aligned(64);
+
+struct stm32_mdma_desc {
+	struct virt_dma_desc vdesc;
+	u32 ccr;
+	struct stm32_mdma_hwdesc *hwdesc;
+	dma_addr_t hwdesc_phys;
+	bool cyclic;
+	u32 count;
+};
+
+struct stm32_mdma_chan {
+	struct virt_dma_chan vchan;
+	struct dma_pool *desc_pool;
+	u32 id;
+	struct stm32_mdma_desc *desc;
+	u32 curr_hwdesc;
+	struct dma_slave_config dma_config;
+	struct stm32_mdma_chan_config chan_config;
+	bool busy;
+	u32 mem_burst;
+	u32 mem_width;
+};
+
+struct stm32_mdma_device {
+	struct dma_device ddev;
+	void __iomem *base;
+	struct clk *clk;
+	int irq;
+	struct reset_control *rst;
+	u32 nr_channels;
+	u32 nr_requests;
+	u32 nr_ahb_addr_masks;
+	struct stm32_mdma_chan chan[STM32_MDMA_MAX_CHANNELS];
+	u32 ahb_addr_masks[];
+};
+
+static struct stm32_mdma_device *stm32_mdma_get_dev(
+	struct stm32_mdma_chan *chan)
+{
+	return container_of(chan->vchan.chan.device, struct stm32_mdma_device,
+			    ddev);
+}
+
+static struct stm32_mdma_chan *to_stm32_mdma_chan(struct dma_chan *c)
+{
+	return container_of(c, struct stm32_mdma_chan, vchan.chan);
+}
+
+static struct stm32_mdma_desc *to_stm32_mdma_desc(struct virt_dma_desc *vdesc)
+{
+	return container_of(vdesc, struct stm32_mdma_desc, vdesc);
+}
+
+static struct device *chan2dev(struct stm32_mdma_chan *chan)
+{
+	return &chan->vchan.chan.dev->device;
+}
+
+static struct device *mdma2dev(struct stm32_mdma_device *mdma_dev)
+{
+	return mdma_dev->ddev.dev;
+}
+
+static u32 stm32_mdma_read(struct stm32_mdma_device *dmadev, u32 reg)
+{
+	return readl_relaxed(dmadev->base + reg);
+}
+
+static void stm32_mdma_write(struct stm32_mdma_device *dmadev, u32 reg, u32 val)
+{
+	writel_relaxed(val, dmadev->base + reg);
+}
+
+static void stm32_mdma_set_bits(struct stm32_mdma_device *dmadev, u32 reg,
+				u32 mask)
+{
+	void __iomem *addr = dmadev->base + reg;
+
+	writel_relaxed(readl_relaxed(addr) | mask, addr);
+}
+
+static void stm32_mdma_clr_bits(struct stm32_mdma_device *dmadev, u32 reg,
+				u32 mask)
+{
+	void __iomem *addr = dmadev->base + reg;
+
+	writel_relaxed(readl_relaxed(addr) & ~mask, addr);
+}
+
+static struct stm32_mdma_desc *stm32_mdma_alloc_desc(
+		struct stm32_mdma_chan *chan, u32 count)
+{
+	struct stm32_mdma_desc *desc;
+
+	desc = kzalloc(sizeof(*desc), GFP_NOWAIT);
+	if (!desc)
+		return NULL;
+
+	desc->hwdesc = dma_pool_alloc(chan->desc_pool, GFP_NOWAIT,
+				      &desc->hwdesc_phys);
+	if (!desc->hwdesc) {
+		dev_err(chan2dev(chan), "Failed to allocate descriptor\n");
+		kfree(desc);
+		return NULL;
+	}
+
+	desc->count = count;
+
+	return desc;
+}
+
+static void stm32_mdma_desc_free(struct virt_dma_desc *vdesc)
+{
+	struct stm32_mdma_desc *desc = to_stm32_mdma_desc(vdesc);
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(vdesc->tx.chan);
+
+	dma_pool_free(chan->desc_pool, desc->hwdesc, desc->hwdesc_phys);
+	kfree(desc);
+}
+
+static int stm32_mdma_get_width(struct stm32_mdma_chan *chan,
+				enum dma_slave_buswidth width)
+{
+	switch (width) {
+	case DMA_SLAVE_BUSWIDTH_1_BYTE:
+	case DMA_SLAVE_BUSWIDTH_2_BYTES:
+	case DMA_SLAVE_BUSWIDTH_4_BYTES:
+	case DMA_SLAVE_BUSWIDTH_8_BYTES:
+		return ffs(width) - 1;
+	default:
+		dev_err(chan2dev(chan), "Dma bus width not supported\n");
+		return -EINVAL;
+	}
+}
+
+static enum dma_slave_buswidth stm32_mdma_get_max_width(u32 buf_len, u32 tlen)
+{
+	enum dma_slave_buswidth max_width = DMA_SLAVE_BUSWIDTH_8_BYTES;
+
+	for (max_width = DMA_SLAVE_BUSWIDTH_8_BYTES;
+	     max_width > DMA_SLAVE_BUSWIDTH_1_BYTE;
+	     max_width >>= 1) {
+		if (((buf_len % max_width) == 0) && (tlen >= max_width))
+			break;
+	}
+
+	return max_width;
+}
+
+static u32 stm32_mdma_get_best_burst(u32 buf_len, u32 tlen, u32 max_burst,
+				     enum dma_slave_buswidth width)
+{
+	u32 best_burst = max_burst;
+	u32 burst_len = best_burst * width;
+
+	while ((burst_len > 0) && (tlen % burst_len)) {
+		best_burst = best_burst >> 1;
+		burst_len = best_burst * width;
+	}
+
+	return (best_burst > 0) ? best_burst : 1;
+}
+
+static int stm32_mdma_disable_chan(struct stm32_mdma_chan *chan)
+{
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	u32 ccr, cisr, id, reg;
+	int ret;
+
+	id = chan->id;
+	reg = STM32_MDMA_CCR(id);
+
+	/* Disable interrupts */
+	stm32_mdma_clr_bits(dmadev, reg, STM32_MDMA_CCR_IRQ_MASK);
+
+	ccr = stm32_mdma_read(dmadev, reg);
+	if (ccr & STM32_MDMA_CCR_EN) {
+		stm32_mdma_clr_bits(dmadev, reg, STM32_MDMA_CCR_EN);
+
+		/* Ensure that any ongoing transfer has been completed */
+		ret = readl_relaxed_poll_timeout_atomic(
+				dmadev->base + STM32_MDMA_CISR(id), cisr,
+				(cisr & STM32_MDMA_CISR_CTCIF), 10, 1000);
+		if (ret) {
+			dev_err(chan2dev(chan), "%s: timeout!\n", __func__);
+			return -EBUSY;
+		}
+	}
+
+	return 0;
+}
+
+static void stm32_mdma_stop(struct stm32_mdma_chan *chan)
+{
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	u32 status;
+	int ret;
+
+	/* Disable DMA */
+	ret = stm32_mdma_disable_chan(chan);
+	if (ret < 0)
+		return;
+
+	/* Clear interrupt status if it is there */
+	status = stm32_mdma_read(dmadev, STM32_MDMA_CISR(chan->id));
+	if (status) {
+		dev_dbg(chan2dev(chan), "%s(): clearing interrupt: 0x%08x\n",
+			__func__, status);
+		stm32_mdma_set_bits(dmadev, STM32_MDMA_CIFCR(chan->id), status);
+	}
+
+	chan->busy = false;
+}
+
+static void stm32_mdma_set_bus(struct stm32_mdma_device *dmadev, u32 *ctbr,
+			       u32 ctbr_mask, u32 src_addr)
+{
+	u32 mask;
+	int i;
+
+	/* Check if memory device is on AHB or AXI */
+	*ctbr &= ~ctbr_mask;
+	mask = src_addr & 0xF0000000;
+	for (i = 0; i < dmadev->nr_ahb_addr_masks; i++) {
+		if (mask == dmadev->ahb_addr_masks[i]) {
+			*ctbr |= ctbr_mask;
+			break;
+		}
+	}
+}
+
+static int stm32_mdma_set_xfer_param(struct stm32_mdma_chan *chan,
+				     enum dma_transfer_direction direction,
+				     u32 *mdma_ccr, u32 *mdma_ctcr,
+				     u32 *mdma_ctbr, u32 buf_len)
+{
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	struct stm32_mdma_chan_config *chan_config = &chan->chan_config;
+	enum dma_slave_buswidth src_addr_width, dst_addr_width;
+	phys_addr_t src_addr, dst_addr;
+	int src_bus_width, dst_bus_width;
+	u32 src_maxburst, dst_maxburst, src_best_burst, dst_best_burst;
+	u32 ccr, ctcr, ctbr, tlen;
+
+	src_addr_width = chan->dma_config.src_addr_width;
+	dst_addr_width = chan->dma_config.dst_addr_width;
+	src_maxburst = chan->dma_config.src_maxburst;
+	dst_maxburst = chan->dma_config.dst_maxburst;
+
+	ccr = stm32_mdma_read(dmadev, STM32_MDMA_CCR(chan->id));
+	ctcr = stm32_mdma_read(dmadev, STM32_MDMA_CTCR(chan->id));
+	ctbr = stm32_mdma_read(dmadev, STM32_MDMA_CTBR(chan->id));
+
+	/* Enable HW request mode */
+	ctcr &= ~STM32_MDMA_CTCR_SWRM;
+
+	/* Set DINC, SINC, DINCOS, SINCOS, TRGM and TLEN retrieve from DT */
+	ctcr &= ~STM32_MDMA_CTCR_CFG_MASK;
+	ctcr |= chan_config->transfer_config & STM32_MDMA_CTCR_CFG_MASK;
+
+	/*
+	 * For buffer transfer length (TLEN) we have to set
+	 * the number of bytes - 1 in CTCR register
+	 */
+	tlen = STM32_MDMA_CTCR_LEN2_GET(ctcr);
+	ctcr &= ~STM32_MDMA_CTCR_LEN2_MSK;
+	ctcr |= STM32_MDMA_CTCR_TLEN((tlen - 1));
+
+	/* Check burst size constraints */
+	if (src_maxburst * src_addr_width > STM32_MDMA_MAX_BURST ||
+	    dst_maxburst * dst_addr_width > STM32_MDMA_MAX_BURST) {
+		dev_err(chan2dev(chan),
+			"burst size * bus width higher than %d bytes\n",
+			STM32_MDMA_MAX_BURST);
+		return -EINVAL;
+	}
+
+	if ((!is_power_of_2(src_maxburst) && src_maxburst > 0) ||
+	    (!is_power_of_2(dst_maxburst) && dst_maxburst > 0)) {
+		dev_err(chan2dev(chan), "burst size must be a power of 2\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * Configure channel control:
+	 * - Clear SW request as in this case this is a HW one
+	 * - Clear WEX, HEX and BEX bits
+	 * - Set priority level
+	 */
+	ccr &= ~(STM32_MDMA_CCR_SWRQ | STM32_MDMA_CCR_WEX | STM32_MDMA_CCR_HEX |
+		 STM32_MDMA_CCR_BEX | STM32_MDMA_CCR_PL_MASK);
+	ccr |= STM32_MDMA_CCR_PL(chan_config->priority_level);
+
+	/* Configure Trigger selection */
+	ctbr &= ~STM32_MDMA_CTBR_TSEL_MASK;
+	ctbr |= STM32_MDMA_CTBR_TSEL(chan_config->request);
+
+	switch (direction) {
+	case DMA_MEM_TO_DEV:
+		/* Set device data size */
+		dst_bus_width = stm32_mdma_get_width(chan, dst_addr_width);
+		if (dst_bus_width < 0)
+			return dst_bus_width;
+		ctcr &= ~STM32_MDMA_CTCR_DSIZE_MASK;
+		ctcr |= STM32_MDMA_CTCR_DSIZE(dst_bus_width);
+
+		/* Set device burst value */
+		dst_best_burst = stm32_mdma_get_best_burst(buf_len, tlen,
+							   dst_maxburst,
+							   dst_addr_width);
+		chan->mem_burst = dst_best_burst;
+		ctcr &= ~STM32_MDMA_CTCR_DBURST_MASK;
+		ctcr |= STM32_MDMA_CTCR_DBURST((ilog2(dst_best_burst)));
+
+		/* Set memory data size */
+		src_addr_width = stm32_mdma_get_max_width(buf_len, tlen);
+		chan->mem_width = src_addr_width;
+		src_bus_width = stm32_mdma_get_width(chan, src_addr_width);
+		if (src_bus_width < 0)
+			return src_bus_width;
+		ctcr &= ~STM32_MDMA_CTCR_SSIZE_MASK |
+			STM32_MDMA_CTCR_SINCOS_MASK;
+		ctcr |= STM32_MDMA_CTCR_SSIZE(src_bus_width) |
+			STM32_MDMA_CTCR_SINCOS(src_bus_width);
+
+		/* Set memory burst value */
+		src_maxburst = STM32_MDMA_MAX_BUF_LEN / src_addr_width;
+		src_best_burst = stm32_mdma_get_best_burst(buf_len, tlen,
+							   src_maxburst,
+							   src_addr_width);
+		chan->mem_burst = src_best_burst;
+		ctcr &= ~STM32_MDMA_CTCR_SBURST_MASK;
+		ctcr |= STM32_MDMA_CTCR_SBURST((ilog2(src_best_burst)));
+
+		/* Select bus */
+		dst_addr = chan->dma_config.dst_addr;
+		stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_DBUS,
+				   dst_addr);
+
+		/* Set destination address */
+		stm32_mdma_write(dmadev, STM32_MDMA_CDAR(chan->id), dst_addr);
+		break;
+
+	case DMA_DEV_TO_MEM:
+		/* Set device data size */
+		src_bus_width = stm32_mdma_get_width(chan, src_addr_width);
+		if (src_bus_width < 0)
+			return src_bus_width;
+		ctcr &= ~STM32_MDMA_CTCR_SSIZE_MASK;
+		ctcr |= STM32_MDMA_CTCR_SSIZE(src_bus_width);
+
+		/* Set device burst value */
+		src_best_burst = stm32_mdma_get_best_burst(buf_len, tlen,
+							   src_maxburst,
+							   src_addr_width);
+		ctcr &= ~STM32_MDMA_CTCR_SBURST_MASK;
+		ctcr |= STM32_MDMA_CTCR_SBURST((ilog2(src_best_burst)));
+
+		/* Set memory data size */
+		dst_addr_width = stm32_mdma_get_max_width(buf_len, tlen);
+		chan->mem_width = dst_addr_width;
+		dst_bus_width = stm32_mdma_get_width(chan, dst_addr_width);
+		if (dst_bus_width < 0)
+			return dst_bus_width;
+		ctcr &= ~(STM32_MDMA_CTCR_DSIZE_MASK |
+			STM32_MDMA_CTCR_DINCOS_MASK);
+		ctcr |= STM32_MDMA_CTCR_DSIZE(dst_bus_width) |
+			STM32_MDMA_CTCR_DINCOS(dst_bus_width);
+
+		/* Set memory burst value */
+		dst_maxburst = STM32_MDMA_MAX_BUF_LEN / dst_addr_width;
+		dst_best_burst = stm32_mdma_get_best_burst(buf_len, tlen,
+							   dst_maxburst,
+							   dst_addr_width);
+		ctcr &= ~STM32_MDMA_CTCR_DBURST_MASK;
+		ctcr |= STM32_MDMA_CTCR_DBURST((ilog2(dst_best_burst)));
+
+		/* Select bus */
+		src_addr = chan->dma_config.src_addr;
+		stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_SBUS,
+				   src_addr);
+
+		/* Set source address */
+		stm32_mdma_write(dmadev, STM32_MDMA_CSAR(chan->id), src_addr);
+		break;
+
+	default:
+		dev_err(chan2dev(chan), "Dma direction is not supported\n");
+		return -EINVAL;
+	}
+
+	*mdma_ccr = ccr;
+	*mdma_ctcr = ctcr;
+	*mdma_ctbr = ctbr;
+
+	return 0;
+}
+
+static void stm32_mdma_dump_hwdesc(struct stm32_mdma_chan *chan,
+				   struct stm32_mdma_hwdesc *hwdesc)
+{
+	dev_dbg(chan2dev(chan), "hwdesc:  0x%08x\n", (unsigned int)hwdesc);
+	dev_dbg(chan2dev(chan), "CTCR:    0x%08x\n", hwdesc->ctcr);
+	dev_dbg(chan2dev(chan), "CBNDTR:  0x%08x\n", hwdesc->cbndtr);
+	dev_dbg(chan2dev(chan), "CSAR:    0x%08x\n", hwdesc->csar);
+	dev_dbg(chan2dev(chan), "CDAR:    0x%08x\n", hwdesc->cdar);
+	dev_dbg(chan2dev(chan), "CBRUR:   0x%08x\n", hwdesc->cbrur);
+	dev_dbg(chan2dev(chan), "CLAR:    0x%08x\n", hwdesc->clar);
+	dev_dbg(chan2dev(chan), "CTBR:    0x%08x\n", hwdesc->ctbr);
+	dev_dbg(chan2dev(chan), "CMAR:    0x%08x\n", hwdesc->cmar);
+	dev_dbg(chan2dev(chan), "CMDR:    0x%08x\n\n", hwdesc->cmdr);
+}
+
+static void stm32_mdma_setup_hwdesc(struct stm32_mdma_chan *chan,
+				    struct stm32_mdma_desc *desc,
+				    enum dma_transfer_direction dir, u32 count,
+				    dma_addr_t src_addr, dma_addr_t dst_addr,
+				    u32 len, u32 ctcr, u32 ctbr, bool is_last,
+				    bool is_first, bool is_cyclic)
+{
+	struct stm32_mdma_chan_config *config = &chan->chan_config;
+	struct stm32_mdma_hwdesc *hwdesc;
+	u32 next = count + 1;
+
+	hwdesc = &desc->hwdesc[count];
+	hwdesc->ctcr = ctcr;
+	hwdesc->cbndtr &= ~(STM32_MDMA_CBNDTR_BRC_MK |
+			STM32_MDMA_CBNDTR_BRDUM |
+			STM32_MDMA_CBNDTR_BRSUM |
+			STM32_MDMA_CBNDTR_BNDT_MASK);
+	hwdesc->cbndtr |= STM32_MDMA_CBNDTR_BNDT(len);
+	hwdesc->csar = src_addr;
+	hwdesc->cdar = dst_addr;
+	hwdesc->cbrur = 0;
+	hwdesc->clar = desc->hwdesc_phys + next * sizeof(*hwdesc);
+	hwdesc->ctbr = ctbr;
+	hwdesc->cmar = config->mask_addr;
+	hwdesc->cmdr = config->mask_data;
+
+	if (is_last) {
+		if (is_cyclic)
+			hwdesc->clar = desc->hwdesc_phys;
+		else
+			hwdesc->clar = 0;
+	}
+
+	stm32_mdma_dump_hwdesc(chan, hwdesc);
+}
+
+static int stm32_mdma_setup_xfer(struct stm32_mdma_chan *chan,
+				 struct stm32_mdma_desc *desc,
+				 struct scatterlist *sgl, u32 sg_len,
+				 enum dma_transfer_direction direction)
+{
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	struct dma_slave_config *dma_config = &chan->dma_config;
+	struct scatterlist *sg;
+	dma_addr_t src_addr, dst_addr;
+	u32 ccr, ctcr, ctbr;
+	int i, ret = 0;
+
+	for_each_sg(sgl, sg, sg_len, i) {
+		if (sg_dma_len(sg) > STM32_MDMA_MAX_BLOCK_LEN) {
+			dev_err(chan2dev(chan), "Invalid block len\n");
+			return -EINVAL;
+		}
+
+		ret = stm32_mdma_set_xfer_param(chan, direction, &ccr, &ctcr,
+						&ctbr, sg_dma_len(sg));
+		if (ret < 0)
+			return ret;
+
+		if (direction == DMA_MEM_TO_DEV) {
+			src_addr = sg_dma_address(sg);
+			dst_addr = dma_config->dst_addr;
+			stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_SBUS,
+					   src_addr);
+		} else {
+			src_addr = dma_config->src_addr;
+			dst_addr = sg_dma_address(sg);
+			stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_DBUS,
+					   dst_addr);
+		}
+
+		stm32_mdma_setup_hwdesc(chan, desc, direction, i, src_addr,
+					dst_addr, sg_dma_len(sg), ctcr, ctbr,
+					i == sg_len - 1, i == 0, false);
+	}
+
+	/* Enable interrupts */
+	ccr &= ~STM32_MDMA_CCR_IRQ_MASK;
+	ccr |= STM32_MDMA_CCR_TEIE | STM32_MDMA_CCR_CTCIE;
+	if (sg_len > 1)
+		ccr |= STM32_MDMA_CCR_BTIE;
+	desc->ccr = ccr;
+
+	return 0;
+}
+
+static struct dma_async_tx_descriptor *
+stm32_mdma_prep_slave_sg(struct dma_chan *c, struct scatterlist *sgl,
+			 u32 sg_len, enum dma_transfer_direction direction,
+			 unsigned long flags, void *context)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	struct stm32_mdma_desc *desc;
+	int ret;
+
+	desc = stm32_mdma_alloc_desc(chan, sg_len);
+	if (!desc)
+		return NULL;
+
+	ret = stm32_mdma_setup_xfer(chan, desc, sgl, sg_len, direction);
+	if (ret < 0)
+		goto xfer_setup_err;
+
+	desc->cyclic = false;
+
+	return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
+
+xfer_setup_err:
+	dma_pool_free(chan->desc_pool, &desc->hwdesc, desc->hwdesc_phys);
+	kfree(desc);
+	return NULL;
+}
+
+static struct dma_async_tx_descriptor *
+stm32_mdma_prep_dma_cyclic(struct dma_chan *c, dma_addr_t buf_addr,
+			   size_t buf_len, size_t period_len,
+			   enum dma_transfer_direction direction,
+			   unsigned long flags)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	struct dma_slave_config *dma_config = &chan->dma_config;
+	struct stm32_mdma_desc *desc;
+	dma_addr_t src_addr, dst_addr;
+	u32 ccr, ctcr, ctbr, count;
+	int i, ret;
+
+	if (!buf_len || !period_len || period_len > STM32_MDMA_MAX_BLOCK_LEN) {
+		dev_err(chan2dev(chan), "Invalid buffer/period len\n");
+		return NULL;
+	}
+
+	if (buf_len % period_len) {
+		dev_err(chan2dev(chan), "buf_len not multiple of period_len\n");
+		return NULL;
+	}
+
+	/*
+	 * We allow to take more number of requests till DMA is
+	 * not started. The driver will loop over all requests.
+	 * Once DMA is started then new requests can be queued only after
+	 * terminating the DMA.
+	 */
+	if (chan->busy) {
+		dev_err(chan2dev(chan), "Request not allowed when dma busy\n");
+		return NULL;
+	}
+
+	count = buf_len / period_len;
+
+	desc = stm32_mdma_alloc_desc(chan, count);
+	if (!desc)
+		return NULL;
+
+	ret = stm32_mdma_set_xfer_param(chan, direction, &ccr, &ctcr, &ctbr,
+					period_len);
+	if (ret < 0)
+		goto xfer_setup_err;
+
+	/* Enable interrupts */
+	ccr &= ~STM32_MDMA_CCR_IRQ_MASK;
+	ccr |= STM32_MDMA_CCR_TEIE | STM32_MDMA_CCR_CTCIE | STM32_MDMA_CCR_BTIE;
+	desc->ccr = ccr;
+
+	/* Select bus */
+	if (direction == DMA_MEM_TO_DEV) {
+		src_addr = buf_addr;
+		stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_SBUS,
+				   src_addr);
+	} else {
+		dst_addr = buf_addr;
+		stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_DBUS,
+				   dst_addr);
+	}
+
+	/* Configure hwdesc list */
+	for (i = 0; i < count; i++) {
+		if (direction == DMA_MEM_TO_DEV) {
+			src_addr = buf_addr + i * period_len;
+			dst_addr = dma_config->dst_addr;
+		} else {
+			src_addr = dma_config->src_addr;
+			dst_addr = buf_addr + i * period_len;
+		}
+
+		stm32_mdma_setup_hwdesc(chan, desc, direction, i, src_addr,
+					dst_addr, period_len, ctcr, ctbr,
+					i == count - 1, i == 0, true);
+	}
+
+	desc->cyclic = true;
+
+	return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
+
+xfer_setup_err:
+	dma_pool_free(chan->desc_pool, &desc->hwdesc, desc->hwdesc_phys);
+	kfree(desc);
+	return NULL;
+}
+
+static struct dma_async_tx_descriptor *
+stm32_mdma_prep_dma_memcpy(struct dma_chan *c, dma_addr_t dest, dma_addr_t src,
+			   size_t len, unsigned long flags)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	enum dma_slave_buswidth max_width;
+	struct stm32_mdma_desc *desc;
+	struct stm32_mdma_hwdesc *hwdesc;
+	u32 ccr, ctcr, ctbr, cbndtr, count, max_burst, mdma_burst;
+	u32 best_burst, tlen;
+	size_t xfer_count, offset;
+	int i;
+
+	count = DIV_ROUND_UP(len, STM32_MDMA_MAX_BLOCK_LEN);
+	desc = stm32_mdma_alloc_desc(chan, count);
+	if (!desc)
+		return NULL;
+
+	ccr = stm32_mdma_read(dmadev, STM32_MDMA_CCR(chan->id));
+	ctcr = stm32_mdma_read(dmadev, STM32_MDMA_CTCR(chan->id));
+	ctbr = stm32_mdma_read(dmadev, STM32_MDMA_CTBR(chan->id));
+	cbndtr = stm32_mdma_read(dmadev, STM32_MDMA_CBNDTR(chan->id));
+
+	/* Enable sw req, some interrupts and clear other bits */
+	ccr &= ~(STM32_MDMA_CCR_WEX | STM32_MDMA_CCR_HEX |
+		 STM32_MDMA_CCR_BEX | STM32_MDMA_CCR_PL_MASK |
+		 STM32_MDMA_CCR_IRQ_MASK);
+	ccr |= STM32_MDMA_CCR_TEIE;
+
+	/* Enable SW request mode, dest/src inc and clear other bits */
+	ctcr &= ~(STM32_MDMA_CTCR_BWM | STM32_MDMA_CTCR_TRGM_MSK |
+		  STM32_MDMA_CTCR_PAM_MASK | STM32_MDMA_CTCR_PKE |
+		  STM32_MDMA_CTCR_TLEN_MSK | STM32_MDMA_CTCR_DBURST_MASK |
+		  STM32_MDMA_CTCR_SBURST_MASK | STM32_MDMA_CTCR_DINCOS_MASK |
+		  STM32_MDMA_CTCR_SINCOS_MASK | STM32_MDMA_CTCR_DSIZE_MASK |
+		  STM32_MDMA_CTCR_SSIZE_MASK | STM32_MDMA_CTCR_DINC_MASK |
+		  STM32_MDMA_CTCR_SINC_MASK);
+	ctcr |= STM32_MDMA_CTCR_SWRM | STM32_MDMA_CTCR_SINC(STM32_MDMA_INC) |
+		STM32_MDMA_CTCR_DINC(STM32_MDMA_INC);
+
+	/* Reset HW request */
+	ctbr &= ~STM32_MDMA_CTBR_TSEL_MASK;
+
+	/* Select bus */
+	stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_SBUS, src);
+	stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_DBUS, dest);
+
+	/* Clear CBNDTR registers */
+	cbndtr &= ~(STM32_MDMA_CBNDTR_BRC_MK | STM32_MDMA_CBNDTR_BRDUM |
+			STM32_MDMA_CBNDTR_BRSUM | STM32_MDMA_CBNDTR_BNDT_MASK);
+
+	if (len <= STM32_MDMA_MAX_BLOCK_LEN) {
+		cbndtr |= STM32_MDMA_CBNDTR_BNDT(len);
+		if (len <= STM32_MDMA_MAX_BUF_LEN) {
+			/* Setup a buffer transfer */
+			tlen = len;
+			ccr |= STM32_MDMA_CCR_TCIE | STM32_MDMA_CCR_CTCIE;
+			ctcr |= STM32_MDMA_CTCR_TRGM(STM32_MDMA_BUFFER);
+			ctcr |= STM32_MDMA_CTCR_TLEN((tlen - 1));
+		} else {
+			/* Setup a block transfer */
+			tlen = STM32_MDMA_MAX_BUF_LEN;
+			ccr |= STM32_MDMA_CCR_BTIE | STM32_MDMA_CCR_CTCIE;
+			ctcr |= STM32_MDMA_CTCR_TRGM(STM32_MDMA_BLOCK);
+			ctcr |= STM32_MDMA_CTCR_TLEN(tlen - 1);
+		}
+
+		/* Set best burst size */
+		max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+		max_burst = tlen / max_width;
+		best_burst = stm32_mdma_get_best_burst(len, tlen, max_burst,
+						       max_width);
+
+		mdma_burst = ilog2(best_burst);
+
+		ctcr |= STM32_MDMA_CTCR_DBURST(mdma_burst) |
+			STM32_MDMA_CTCR_SBURST(mdma_burst);
+
+		/* Prepare hardware descriptor */
+		hwdesc = desc->hwdesc;
+		hwdesc->ctcr = ctcr;
+		hwdesc->cbndtr = cbndtr;
+		hwdesc->csar = src;
+		hwdesc->cdar = dest;
+		hwdesc->cbrur = 0;
+		hwdesc->clar = 0;
+		hwdesc->ctbr = ctbr;
+		hwdesc->cmar = 0;
+		hwdesc->cmdr = 0;
+
+		stm32_mdma_dump_hwdesc(chan, hwdesc);
+	} else {
+		/* Setup a LLI transfer */
+		ctcr |= STM32_MDMA_CTCR_TRGM(STM32_MDMA_LINKED_LIST) |
+			STM32_MDMA_CTCR_TLEN((STM32_MDMA_MAX_BUF_LEN - 1));
+		ccr |= STM32_MDMA_CCR_BTIE | STM32_MDMA_CCR_CTCIE;
+		tlen = STM32_MDMA_MAX_BUF_LEN;
+
+		for (i = 0, offset = 0; offset < len;
+		     i++, offset += xfer_count) {
+			xfer_count = min_t(size_t, len - offset,
+					   STM32_MDMA_MAX_BLOCK_LEN);
+
+			/* Set best burst size */
+			max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+			max_burst = STM32_MDMA_MAX_BUF_LEN / max_width;
+			best_burst = stm32_mdma_get_best_burst(xfer_count, tlen,
+							       max_burst,
+							       max_width);
+			mdma_burst = ilog2(best_burst);
+
+			ctcr &= ~(STM32_MDMA_CTCR_DBURST_MASK |
+				  STM32_MDMA_CTCR_SBURST_MASK);
+			ctcr |= STM32_MDMA_CTCR_DBURST(mdma_burst) |
+				STM32_MDMA_CTCR_SBURST(mdma_burst);
+
+			/* Prepare hardware descriptor */
+			stm32_mdma_setup_hwdesc(chan, desc, DMA_MEM_TO_MEM, i,
+						src + offset, dest + offset,
+						xfer_count, ctcr, ctbr,
+						i == count - 1, i == 0, false);
+		}
+	}
+
+	desc->ccr = ccr;
+
+	desc->cyclic = false;
+
+	return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
+}
+
+static void stm32_mdma_dump_reg(struct stm32_mdma_chan *chan)
+{
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+
+	dev_dbg(chan2dev(chan), "CCR:     0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CCR(chan->id)));
+	dev_dbg(chan2dev(chan), "CTCR:    0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CTCR(chan->id)));
+	dev_dbg(chan2dev(chan), "CBNDTR:  0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CBNDTR(chan->id)));
+	dev_dbg(chan2dev(chan), "CSAR:    0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CSAR(chan->id)));
+	dev_dbg(chan2dev(chan), "CDAR:    0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CDAR(chan->id)));
+	dev_dbg(chan2dev(chan), "CBRUR:   0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CBRUR(chan->id)));
+	dev_dbg(chan2dev(chan), "CLAR:    0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CLAR(chan->id)));
+	dev_dbg(chan2dev(chan), "CTBR:    0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CTBR(chan->id)));
+	dev_dbg(chan2dev(chan), "CMAR:    0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CMAR(chan->id)));
+	dev_dbg(chan2dev(chan), "CMDR:    0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CMDR(chan->id)));
+}
+
+static void stm32_mdma_start_transfer(struct stm32_mdma_chan *chan)
+{
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	struct virt_dma_desc *vdesc;
+	struct stm32_mdma_hwdesc *hwdesc;
+	u32 id = chan->id;
+	u32 status, reg;
+
+	vdesc = vchan_next_desc(&chan->vchan);
+	if (!vdesc) {
+		chan->desc = NULL;
+		return;
+	}
+
+	chan->desc = to_stm32_mdma_desc(vdesc);
+	hwdesc = chan->desc->hwdesc;
+	chan->curr_hwdesc = 0;
+
+	stm32_mdma_write(dmadev, STM32_MDMA_CCR(id), chan->desc->ccr);
+	stm32_mdma_write(dmadev, STM32_MDMA_CTCR(id), hwdesc->ctcr);
+	stm32_mdma_write(dmadev, STM32_MDMA_CBNDTR(id), hwdesc->cbndtr);
+	stm32_mdma_write(dmadev, STM32_MDMA_CSAR(id), hwdesc->csar);
+	stm32_mdma_write(dmadev, STM32_MDMA_CDAR(id), hwdesc->cdar);
+	stm32_mdma_write(dmadev, STM32_MDMA_CBRUR(id), hwdesc->cbrur);
+	stm32_mdma_write(dmadev, STM32_MDMA_CLAR(id), hwdesc->clar);
+	stm32_mdma_write(dmadev, STM32_MDMA_CTBR(id), hwdesc->ctbr);
+	stm32_mdma_write(dmadev, STM32_MDMA_CMAR(id), hwdesc->cmar);
+	stm32_mdma_write(dmadev, STM32_MDMA_CMDR(id), hwdesc->cmdr);
+
+	/* Clear interrupt status if it is there */
+	status = stm32_mdma_read(dmadev, STM32_MDMA_CISR(id));
+	if (status)
+		stm32_mdma_set_bits(dmadev, STM32_MDMA_CIFCR(id), status);
+
+	stm32_mdma_dump_reg(chan);
+
+	/* Start DMA */
+	stm32_mdma_set_bits(dmadev, STM32_MDMA_CCR(id), STM32_MDMA_CCR_EN);
+
+	/* Set SW request in case of MEM2MEM transfer */
+	if (hwdesc->ctcr & STM32_MDMA_CTCR_SWRM) {
+		reg = STM32_MDMA_CCR(id);
+		stm32_mdma_set_bits(dmadev, reg, STM32_MDMA_CCR_SWRQ);
+	}
+
+	chan->busy = true;
+
+	dev_dbg(chan2dev(chan), "vchan %p: started\n", &chan->vchan);
+}
+
+static void stm32_mdma_issue_pending(struct dma_chan *c)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	unsigned long flags;
+
+	spin_lock_irqsave(&chan->vchan.lock, flags);
+
+	if (!vchan_issue_pending(&chan->vchan))
+		goto end;
+
+	dev_dbg(chan2dev(chan), "vchan %p: issued\n", &chan->vchan);
+
+	if (!chan->desc && !chan->busy)
+		stm32_mdma_start_transfer(chan);
+
+end:
+	spin_unlock_irqrestore(&chan->vchan.lock, flags);
+}
+
+static int stm32_mdma_pause(struct dma_chan *c)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&chan->vchan.lock, flags);
+	ret = stm32_mdma_disable_chan(chan);
+	spin_unlock_irqrestore(&chan->vchan.lock, flags);
+
+	if (!ret)
+		dev_dbg(chan2dev(chan), "vchan %p: pause\n", &chan->vchan);
+
+	return ret;
+}
+
+static int stm32_mdma_resume(struct dma_chan *c)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	struct stm32_mdma_hwdesc *hwdesc;
+	unsigned long flags;
+	u32 status, reg;
+
+	hwdesc = &chan->desc->hwdesc[chan->curr_hwdesc];
+
+	spin_lock_irqsave(&chan->vchan.lock, flags);
+
+	/* Re-configure control register */
+	stm32_mdma_write(dmadev, STM32_MDMA_CCR(chan->id), chan->desc->ccr);
+
+	/* Clear interrupt status if it is there */
+	status = stm32_mdma_read(dmadev, STM32_MDMA_CISR(chan->id));
+	if (status)
+		stm32_mdma_set_bits(dmadev, STM32_MDMA_CIFCR(chan->id), status);
+
+	stm32_mdma_dump_reg(chan);
+
+	/* Re-start DMA */
+	reg = STM32_MDMA_CCR(chan->id);
+	stm32_mdma_set_bits(dmadev, reg, STM32_MDMA_CCR_EN);
+
+	/* Set SW request in case of MEM2MEM transfer */
+	if (hwdesc->ctcr & STM32_MDMA_CTCR_SWRM)
+		stm32_mdma_set_bits(dmadev, reg, STM32_MDMA_CCR_SWRQ);
+
+	spin_unlock_irqrestore(&chan->vchan.lock, flags);
+
+	dev_dbg(chan2dev(chan), "vchan %p: resume\n", &chan->vchan);
+
+	return 0;
+}
+
+static int stm32_mdma_terminate_all(struct dma_chan *c)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	unsigned long flags;
+	LIST_HEAD(head);
+
+	spin_lock_irqsave(&chan->vchan.lock, flags);
+	if (chan->busy) {
+		stm32_mdma_stop(chan);
+		chan->desc = NULL;
+	}
+	vchan_get_all_descriptors(&chan->vchan, &head);
+	spin_unlock_irqrestore(&chan->vchan.lock, flags);
+
+	vchan_dma_desc_free_list(&chan->vchan, &head);
+
+	return 0;
+}
+
+static void stm32_mdma_synchronize(struct dma_chan *c)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+
+	vchan_synchronize(&chan->vchan);
+}
+
+static int stm32_mdma_slave_config(struct dma_chan *c,
+				   struct dma_slave_config *config)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+
+	memcpy(&chan->dma_config, config, sizeof(*config));
+
+	return 0;
+}
+
+static size_t stm32_mdma_desc_residue(struct stm32_mdma_chan *chan,
+				      struct stm32_mdma_desc *desc,
+				      u32 curr_hwdesc)
+{
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	struct stm32_mdma_hwdesc *hwdesc = desc->hwdesc;
+	u32 cbndtr, residue, modulo, burst_size;
+	int i;
+
+	residue = 0;
+	for (i = curr_hwdesc + 1; i < desc->count; i++) {
+		hwdesc = &desc->hwdesc[i];
+		residue += STM32_MDMA_CBNDTR_BNDT(hwdesc->cbndtr);
+	}
+	cbndtr = stm32_mdma_read(dmadev, STM32_MDMA_CBNDTR(chan->id));
+	residue += cbndtr & STM32_MDMA_CBNDTR_BNDT_MASK;
+
+	if (!chan->mem_burst)
+		return residue;
+
+	burst_size = chan->mem_burst * chan->mem_width;
+	modulo = residue % burst_size;
+	if (modulo)
+		residue = residue - modulo + burst_size;
+
+	return residue;
+}
+
+static enum dma_status stm32_mdma_tx_status(struct dma_chan *c,
+					    dma_cookie_t cookie,
+					    struct dma_tx_state *state)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	struct virt_dma_desc *vdesc;
+	enum dma_status status;
+	unsigned long flags;
+	u32 residue = 0;
+
+	status = dma_cookie_status(c, cookie, state);
+	if ((status == DMA_COMPLETE) || (!state))
+		return status;
+
+	spin_lock_irqsave(&chan->vchan.lock, flags);
+
+	vdesc = vchan_find_desc(&chan->vchan, cookie);
+	if (chan->desc && cookie == chan->desc->vdesc.tx.cookie)
+		residue = stm32_mdma_desc_residue(chan, chan->desc,
+						  chan->curr_hwdesc);
+	else if (vdesc)
+		residue = stm32_mdma_desc_residue(chan,
+						  to_stm32_mdma_desc(vdesc), 0);
+	dma_set_residue(state, residue);
+
+	spin_unlock_irqrestore(&chan->vchan.lock, flags);
+
+	return status;
+}
+
+static void stm32_mdma_xfer_end(struct stm32_mdma_chan *chan)
+{
+	list_del(&chan->desc->vdesc.node);
+	vchan_cookie_complete(&chan->desc->vdesc);
+	chan->desc = NULL;
+	chan->busy = false;
+
+	/* Start the next transfer if this driver has a next desc */
+	stm32_mdma_start_transfer(chan);
+}
+
+static irqreturn_t stm32_mdma_irq_handler(int irq, void *devid)
+{
+	struct stm32_mdma_device *dmadev = devid;
+	struct stm32_mdma_chan *chan = devid;
+	u32 reg, id, ien, status, flag;
+
+	/* Find out which channel generates the interrupt */
+	status = readl_relaxed(dmadev->base + STM32_MDMA_GISR0);
+	if (status) {
+		id = __ffs(status);
+	} else {
+		status = readl_relaxed(dmadev->base + STM32_MDMA_GISR1);
+		if (!status) {
+			dev_dbg(mdma2dev(dmadev), "spurious it\n");
+			return IRQ_NONE;
+		}
+		id = __ffs(status);
+		/*
+		 * As GISR0 provides status for channel id from 0 to 31,
+		 * so GISR1 provides status for channel id from 32 to 62
+		 */
+		id += 32;
+	}
+
+	chan = &dmadev->chan[id];
+	if (!chan) {
+		dev_err(chan2dev(chan), "MDMA channel not initialized\n");
+		goto exit;
+	}
+
+	/* Handle interrupt for the channel */
+	spin_lock(&chan->vchan.lock);
+	status = stm32_mdma_read(dmadev, STM32_MDMA_CISR(chan->id));
+	ien = stm32_mdma_read(dmadev, STM32_MDMA_CCR(chan->id));
+	ien &= STM32_MDMA_CCR_IRQ_MASK;
+	ien >>= 1;
+
+	if (!(status & ien)) {
+		spin_unlock(&chan->vchan.lock);
+		dev_dbg(chan2dev(chan),
+			"spurious it (status=0x%04x, ien=0x%04x)\n",
+			status, ien);
+		return IRQ_NONE;
+	}
+
+	flag = __ffs(status & ien);
+	reg = STM32_MDMA_CIFCR(chan->id);
+
+	switch (1 << flag) {
+	case STM32_MDMA_CISR_TEIF:
+		id = chan->id;
+		status = readl_relaxed(dmadev->base + STM32_MDMA_CESR(id));
+		dev_err(chan2dev(chan), "Transfer Err: stat=0x%08x\n", status);
+		stm32_mdma_set_bits(dmadev, reg, STM32_MDMA_CIFCR_CTEIF);
+		break;
+
+	case STM32_MDMA_CISR_CTCIF:
+		stm32_mdma_set_bits(dmadev, reg, STM32_MDMA_CIFCR_CCTCIF);
+		stm32_mdma_xfer_end(chan);
+		break;
+
+	case STM32_MDMA_CISR_BRTIF:
+		stm32_mdma_set_bits(dmadev, reg, STM32_MDMA_CIFCR_CBRTIF);
+		break;
+
+	case STM32_MDMA_CISR_BTIF:
+		stm32_mdma_set_bits(dmadev, reg, STM32_MDMA_CIFCR_CBTIF);
+		chan->curr_hwdesc++;
+		if (chan->desc && chan->desc->cyclic) {
+			if (chan->curr_hwdesc == chan->desc->count)
+				chan->curr_hwdesc = 0;
+			vchan_cyclic_callback(&chan->desc->vdesc);
+		}
+		break;
+
+	case STM32_MDMA_CISR_TCIF:
+		stm32_mdma_set_bits(dmadev, reg, STM32_MDMA_CIFCR_CLTCIF);
+		break;
+
+	default:
+		dev_err(chan2dev(chan), "it %d unhandled (status=0x%04x)\n",
+			1 << flag, status);
+	}
+
+	spin_unlock(&chan->vchan.lock);
+
+exit:
+	return IRQ_HANDLED;
+}
+
+static int stm32_mdma_alloc_chan_resources(struct dma_chan *c)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	int ret;
+
+	chan->desc_pool = dmam_pool_create(dev_name(&c->dev->device),
+					   c->device->dev,
+					   sizeof(struct stm32_mdma_hwdesc),
+					  __alignof__(struct stm32_mdma_hwdesc),
+					   0);
+	if (!chan->desc_pool) {
+		dev_err(chan2dev(chan), "failed to allocate descriptor pool\n");
+		return -ENOMEM;
+	}
+
+	ret = clk_prepare_enable(dmadev->clk);
+	if (ret < 0) {
+		dev_err(chan2dev(chan), "clk_prepare_enable failed: %d\n", ret);
+		return ret;
+	}
+
+	ret = stm32_mdma_disable_chan(chan);
+	if (ret < 0)
+		clk_disable_unprepare(dmadev->clk);
+
+	return ret;
+}
+
+static void stm32_mdma_free_chan_resources(struct dma_chan *c)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	unsigned long flags;
+
+	dev_dbg(chan2dev(chan), "Freeing channel %d\n", chan->id);
+
+	if (chan->busy) {
+		spin_lock_irqsave(&chan->vchan.lock, flags);
+		stm32_mdma_stop(chan);
+		chan->desc = NULL;
+		spin_unlock_irqrestore(&chan->vchan.lock, flags);
+	}
+
+	clk_disable_unprepare(dmadev->clk);
+	vchan_free_chan_resources(to_virt_chan(c));
+	dmam_pool_destroy(chan->desc_pool);
+	chan->desc_pool = NULL;
+}
+
+static struct dma_chan *stm32_mdma_of_xlate(struct of_phandle_args *dma_spec,
+					    struct of_dma *ofdma)
+{
+	struct stm32_mdma_device *dmadev = ofdma->of_dma_data;
+	struct stm32_mdma_chan *chan;
+	struct dma_chan *c;
+	struct stm32_mdma_chan_config config;
+
+	if (dma_spec->args_count < 5) {
+		dev_err(mdma2dev(dmadev), "Bad number of args\n");
+		return NULL;
+	}
+
+	config.request = dma_spec->args[0];
+	config.priority_level = dma_spec->args[1];
+	config.transfer_config = dma_spec->args[2];
+	config.mask_addr = dma_spec->args[3];
+	config.mask_data = dma_spec->args[4];
+
+	if (config.request >= dmadev->nr_requests) {
+		dev_err(mdma2dev(dmadev), "Bad request line\n");
+		return NULL;
+	}
+
+	if (config.priority_level > STM32_MDMA_VERY_HIGH_PRIORITY) {
+		dev_err(mdma2dev(dmadev), "Priority level not supported\n");
+		return NULL;
+	}
+
+	c = dma_get_any_slave_channel(&dmadev->ddev);
+	if (!c) {
+		dev_err(mdma2dev(dmadev), "No more channel avalaible\n");
+		return NULL;
+	}
+
+	chan = to_stm32_mdma_chan(c);
+	chan->chan_config = config;
+
+	return c;
+}
+
+static const struct of_device_id stm32_mdma_of_match[] = {
+	{ .compatible = "st,stm32h7-mdma", },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, stm32_mdma_of_match);
+
+static int stm32_mdma_probe(struct platform_device *pdev)
+{
+	struct stm32_mdma_chan *chan;
+	struct stm32_mdma_device *dmadev;
+	struct dma_device *dd;
+	struct device_node *of_node;
+	struct resource *res;
+	u32 nr_channels, nr_requests;
+	int i, count, ret;
+
+	of_node = pdev->dev.of_node;
+	if (!of_node)
+		return -ENODEV;
+
+	ret = device_property_read_u32(&pdev->dev, "dma-channels",
+				       &nr_channels);
+	if (ret) {
+		nr_channels = STM32_MDMA_MAX_CHANNELS;
+		dev_warn(&pdev->dev, "MDMA defaulting on %i channels\n",
+			 nr_channels);
+	}
+
+	ret = device_property_read_u32(&pdev->dev, "dma-requests",
+				       &nr_requests);
+	if (ret) {
+		nr_requests = STM32_MDMA_MAX_REQUESTS;
+		dev_warn(&pdev->dev, "MDMA defaulting on %i request lines\n",
+			 nr_requests);
+	}
+
+	count = of_property_count_u32_elems(of_node, "st,ahb-addr-masks");
+	if (count < 0)
+		count = 0;
+
+	dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev) + sizeof(u32) * count,
+			      GFP_KERNEL);
+	if (!dmadev)
+		return -ENOMEM;
+
+	dmadev->nr_channels = nr_channels;
+	dmadev->nr_requests = nr_requests;
+	of_property_read_u32_array(of_node, "st,ahb-addr-masks",
+				   dmadev->ahb_addr_masks,
+				   count);
+	dmadev->nr_ahb_addr_masks = count;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	dmadev->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(dmadev->base))
+		return PTR_ERR(dmadev->base);
+
+	dmadev->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(dmadev->clk)) {
+		dev_err(&pdev->dev, "Error: Missing controller clock\n");
+		return PTR_ERR(dmadev->clk);
+	}
+
+	dmadev->rst = devm_reset_control_get(&pdev->dev, NULL);
+	if (!IS_ERR(dmadev->rst)) {
+		reset_control_assert(dmadev->rst);
+		udelay(2);
+		reset_control_deassert(dmadev->rst);
+	}
+
+	dd = &dmadev->ddev;
+	dma_cap_set(DMA_SLAVE, dd->cap_mask);
+	dma_cap_set(DMA_PRIVATE, dd->cap_mask);
+	dma_cap_set(DMA_CYCLIC, dd->cap_mask);
+	dma_cap_set(DMA_MEMCPY, dd->cap_mask);
+	dd->device_alloc_chan_resources = stm32_mdma_alloc_chan_resources;
+	dd->device_free_chan_resources = stm32_mdma_free_chan_resources;
+	dd->device_tx_status = stm32_mdma_tx_status;
+	dd->device_issue_pending = stm32_mdma_issue_pending;
+	dd->device_prep_slave_sg = stm32_mdma_prep_slave_sg;
+	dd->device_prep_dma_cyclic = stm32_mdma_prep_dma_cyclic;
+	dd->device_prep_dma_memcpy = stm32_mdma_prep_dma_memcpy;
+	dd->device_config = stm32_mdma_slave_config;
+	dd->device_pause = stm32_mdma_pause;
+	dd->device_resume = stm32_mdma_resume;
+	dd->device_terminate_all = stm32_mdma_terminate_all;
+	dd->device_synchronize = stm32_mdma_synchronize;
+	dd->src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
+		BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
+		BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) |
+		BIT(DMA_SLAVE_BUSWIDTH_8_BYTES);
+	dd->dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
+		BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
+		BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) |
+		BIT(DMA_SLAVE_BUSWIDTH_8_BYTES);
+	dd->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV) |
+		BIT(DMA_MEM_TO_MEM);
+	dd->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
+	dd->max_burst = STM32_MDMA_MAX_BURST;
+	dd->dev = &pdev->dev;
+	INIT_LIST_HEAD(&dd->channels);
+
+	for (i = 0; i < dmadev->nr_channels; i++) {
+		chan = &dmadev->chan[i];
+		chan->id = i;
+		chan->vchan.desc_free = stm32_mdma_desc_free;
+		vchan_init(&chan->vchan, dd);
+	}
+
+	dmadev->irq = platform_get_irq(pdev, 0);
+	if (dmadev->irq < 0) {
+		dev_err(&pdev->dev, "failed to get IRQ\n");
+		return dmadev->irq;
+	}
+
+	ret = devm_request_irq(&pdev->dev, dmadev->irq, stm32_mdma_irq_handler,
+			       0, dev_name(&pdev->dev), dmadev);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to request IRQ\n");
+		return ret;
+	}
+
+	ret = dma_async_device_register(dd);
+	if (ret)
+		return ret;
+
+	ret = of_dma_controller_register(of_node, stm32_mdma_of_xlate, dmadev);
+	if (ret < 0) {
+		dev_err(&pdev->dev,
+			"STM32 MDMA DMA OF registration failed %d\n", ret);
+		goto err_unregister;
+	}
+
+	platform_set_drvdata(pdev, dmadev);
+
+	dev_info(&pdev->dev, "STM32 MDMA driver registered\n");
+
+	return 0;
+
+err_unregister:
+	dma_async_device_unregister(dd);
+
+	return ret;
+}
+
+static struct platform_driver stm32_mdma_driver = {
+	.driver = {
+		.name = "stm32-mdma",
+		.of_match_table = stm32_mdma_of_match,
+	},
+};
+
+static int __init stm32_mdma_init(void)
+{
+	return platform_driver_probe(&stm32_mdma_driver, stm32_mdma_probe);
+}
+
+subsys_initcall(stm32_mdma_init);
+
+MODULE_DESCRIPTION("Driver for STM32 MDMA controller");
+MODULE_AUTHOR("M'boumba Cedric Madianga <cedric.madianga@gmail.com>");
+MODULE_AUTHOR("Pierre-Yves Mordret <pierre-yves.mordret@st.com>");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 26+ messages in thread

* [PATCH v3 2/4] dmaengine: Add STM32 MDMA driver
@ 2017-07-26  9:48   ` Pierre-Yves MORDRET
  0 siblings, 0 replies; 26+ messages in thread
From: Pierre-Yves MORDRET @ 2017-07-26  9:48 UTC (permalink / raw)
  To: Vinod Koul, Rob Herring, Mark Rutland, Maxime Coquelin,
	Alexandre Torgue, Russell King, Dan Williams,
	M'boumba Cedric Madianga, Fabrice GASNIER, Herbert Xu,
	Fabien DESSENNE, Amelie Delaunay, Pierre-Yves MORDRET, dmaengine,
	devicetree, linux-arm-kernel, linux-kernel

This patch adds the driver for the STM32 MDMA controller.

Master Direct memory access (MDMA) is used in order to provide high-speed
data transfer between memory and memory or between peripherals and memory.

MDMA controller provides a master AXI interface for main memory and
peripheral registers access (system access port) and a master AHB
interface only for Cortex-M7 TCM memory access (TCM access port).

MDMA works in conjunction with the standard DMA controllers (DMA1 or DMA2).
It offers up to 64 channels, each dedicated to managing memory access
requests from one of the DMA stream memory buffer or other peripherals
(w/ integrated FIFO).

Signed-off-by: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
---
  Version history:
     v3:
         * Update header template
         * Unsigned expression compared with zero
         * Rework stm32_mdma_get_max_width
         * moved to src/dst case where they are used in set_xfer
         * Change of_property_* with device_property_*
         * Add dev_warn whether default value is used
         * Indentation
         * Add MODULE_*
     v2:
         * change compatible into st,stm32h7-mdma to be more SoC specific
         * optimize some functions
         * functions factorization
         * remove useless code
---
---
 drivers/dma/Kconfig      |   12 +
 drivers/dma/Makefile     |    1 +
 drivers/dma/stm32-mdma.c | 1565 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 1578 insertions(+)
 create mode 100644 drivers/dma/stm32-mdma.c

diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index fadc4d8..36cac16 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -483,6 +483,18 @@ config STM32_DMA
 	  If you have a board based on such a MCU and wish to use DMA say Y
 	  here.
 
+config STM32_MDMA
+	bool "STMicroelectronics STM32 master dma support"
+	depends on ARCH_STM32 || COMPILE_TEST
+	select DMA_ENGINE
+	select DMA_OF
+	select DMA_VIRTUAL_CHANNELS
+	help
+	  Enable support for the on-chip MDMA controller on STMicroelectronics
+	  STM32 platforms.
+	  If you have a board based on STM32 SoC and wish to use the master DMA
+	  say Y here.
+
 config S3C24XX_DMAC
 	bool "Samsung S3C24XX DMA support"
 	depends on ARCH_S3C24XX || COMPILE_TEST
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index f08f8de..b9747ba 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -59,6 +59,7 @@ obj-$(CONFIG_RENESAS_DMA) += sh/
 obj-$(CONFIG_SIRF_DMA) += sirf-dma.o
 obj-$(CONFIG_STE_DMA40) += ste_dma40.o ste_dma40_ll.o
 obj-$(CONFIG_STM32_DMA) += stm32-dma.o
+obj-$(CONFIG_STM32_MDMA) += stm32-mdma.o
 obj-$(CONFIG_S3C24XX_DMAC) += s3c24xx-dma.o
 obj-$(CONFIG_TXX9_DMAC) += txx9dmac.o
 obj-$(CONFIG_TEGRA20_APB_DMA) += tegra20-apb-dma.o
diff --git a/drivers/dma/stm32-mdma.c b/drivers/dma/stm32-mdma.c
new file mode 100644
index 0000000..a5b351b
--- /dev/null
+++ b/drivers/dma/stm32-mdma.c
@@ -0,0 +1,1565 @@
+/*
+ *
+ * Copyright (C) STMicroelectronics SA 2017
+ * Author(s): M'boumba Cedric Madianga <cedric.madianga@gmail.com>
+ *            Pierre-Yves Mordret <pierre-yves.mordret@st.com>
+ *
+ * License terms: GPL V2.0.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+ * details.
+ *
+ * Driver for STM32 MDMA controller
+ *
+ * Inspired by stm32-dma.c and dma-jz4780.c
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmapool.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/iopoll.h>
+#include <linux/jiffies.h>
+#include <linux/list.h>
+#include <linux/log2.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_dma.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+
+#include "virt-dma.h"
+
+#define STM32_MDMA_GISR0		0x0000 /* MDMA Int Status Reg 1 */
+#define STM32_MDMA_GISR1		0x0004 /* MDMA Int Status Reg 2 */
+
+/* MDMA Channel x interrupt/status register */
+#define STM32_MDMA_CISR(x)		(0x40 + 0x40 * (x)) /* x = 0..62 */
+#define STM32_MDMA_CISR_CRQA		BIT(16)
+#define STM32_MDMA_CISR_TCIF		BIT(4)
+#define STM32_MDMA_CISR_BTIF		BIT(3)
+#define STM32_MDMA_CISR_BRTIF		BIT(2)
+#define STM32_MDMA_CISR_CTCIF		BIT(1)
+#define STM32_MDMA_CISR_TEIF		BIT(0)
+
+/* MDMA Channel x interrupt flag clear register */
+#define STM32_MDMA_CIFCR(x)		(0x44 + 0x40 * (x))
+#define STM32_MDMA_CIFCR_CLTCIF		BIT(4)
+#define STM32_MDMA_CIFCR_CBTIF		BIT(3)
+#define STM32_MDMA_CIFCR_CBRTIF		BIT(2)
+#define STM32_MDMA_CIFCR_CCTCIF		BIT(1)
+#define STM32_MDMA_CIFCR_CTEIF		BIT(0)
+#define STM32_MDMA_CIFCR_CLEAR_ALL	(STM32_MDMA_CIFCR_CLTCIF \
+					| STM32_MDMA_CIFCR_CBTIF \
+					| STM32_MDMA_CIFCR_CBRTIF \
+					| STM32_MDMA_CIFCR_CCTCIF \
+					| STM32_MDMA_CIFCR_CTEIF)
+
+/* MDMA Channel x error status register */
+#define STM32_MDMA_CESR(x)		(0x48 + 0x40 * (x))
+#define STM32_MDMA_CESR_BSE		BIT(11)
+#define STM32_MDMA_CESR_ASR		BIT(10)
+#define STM32_MDMA_CESR_TEMD		BIT(9)
+#define STM32_MDMA_CESR_TELD		BIT(8)
+#define STM32_MDMA_CESR_TED		BIT(7)
+#define STM32_MDMA_CESR_TEA_MASK	GENMASK(6, 0)
+
+/* MDMA Channel x control register */
+#define STM32_MDMA_CCR(x)		(0x4C + 0x40 * (x))
+#define STM32_MDMA_CCR_SWRQ		BIT(16)
+#define STM32_MDMA_CCR_WEX		BIT(14)
+#define STM32_MDMA_CCR_HEX		BIT(13)
+#define STM32_MDMA_CCR_BEX		BIT(12)
+#define STM32_MDMA_CCR_PL_MASK		GENMASK(7, 6)
+#define STM32_MDMA_CCR_PL(n)		(((n) & 0x3) << 6)
+#define STM32_MDMA_CCR_TCIE		BIT(5)
+#define STM32_MDMA_CCR_BTIE		BIT(4)
+#define STM32_MDMA_CCR_BRTIE		BIT(3)
+#define STM32_MDMA_CCR_CTCIE		BIT(2)
+#define STM32_MDMA_CCR_TEIE		BIT(1)
+#define STM32_MDMA_CCR_EN		BIT(0)
+#define STM32_MDMA_CCR_IRQ_MASK		(STM32_MDMA_CCR_TCIE \
+					| STM32_MDMA_CCR_BTIE \
+					| STM32_MDMA_CCR_BRTIE \
+					| STM32_MDMA_CCR_CTCIE \
+					| STM32_MDMA_CCR_TEIE)
+
+/* MDMA Channel x transfer configuration register */
+#define STM32_MDMA_CTCR(x)		(0x50 + 0x40 * (x))
+#define STM32_MDMA_CTCR_BWM		BIT(31)
+#define STM32_MDMA_CTCR_SWRM		BIT(30)
+#define STM32_MDMA_CTCR_TRGM_MSK	GENMASK(29, 28)
+#define STM32_MDMA_CTCR_TRGM(n)		(((n) & 0x3) << 28)
+#define STM32_MDMA_CTCR_TRGM_GET(n)	(((n) & STM32_MDMA_CTCR_TRGM_MSK) >> 28)
+#define STM32_MDMA_CTCR_PAM_MASK	GENMASK(27, 26)
+#define STM32_MDMA_CTCR_PAM(n)		(((n) & 0x3) << 26)
+#define STM32_MDMA_CTCR_PKE		BIT(25)
+#define STM32_MDMA_CTCR_TLEN_MSK	GENMASK(24, 18)
+#define STM32_MDMA_CTCR_TLEN(n)		(((n) & 0x7f) << 18)
+#define STM32_MDMA_CTCR_TLEN_GET(n)	(((n) & STM32_MDMA_CTCR_TLEN_MSK) >> 18)
+#define STM32_MDMA_CTCR_LEN2_MSK	GENMASK(25, 18)
+#define STM32_MDMA_CTCR_LEN2(n)	(((n) & 0xff) << 18)
+#define STM32_MDMA_CTCR_LEN2_GET(n)	(((n) & STM32_MDMA_CTCR_LEN2_MSK) >> 18)
+#define STM32_MDMA_CTCR_DBURST_MASK	GENMASK(17, 15)
+#define STM32_MDMA_CTCR_DBURST(n)	(((n) & 0x7) << 15)
+#define STM32_MDMA_CTCR_SBURST_MASK	GENMASK(14, 12)
+#define STM32_MDMA_CTCR_SBURST(n)	(((n) & 0x7) << 12)
+#define STM32_MDMA_CTCR_DINCOS_MASK	GENMASK(11, 10)
+#define STM32_MDMA_CTCR_DINCOS(n)	(((n) & 0x3) << 10)
+#define STM32_MDMA_CTCR_SINCOS_MASK	GENMASK(9, 8)
+#define STM32_MDMA_CTCR_SINCOS(n)	(((n) & 0x3) << 8)
+#define STM32_MDMA_CTCR_DSIZE_MASK	GENMASK(7, 6)
+#define STM32_MDMA_CTCR_DSIZE(n)	(((n) & 0x3) << 6)
+#define STM32_MDMA_CTCR_SSIZE_MASK	GENMASK(5, 4)
+#define STM32_MDMA_CTCR_SSIZE(n)	(((n) & 0x3) << 4)
+#define STM32_MDMA_CTCR_DINC_MASK	GENMASK(3, 2)
+#define STM32_MDMA_CTCR_DINC(n)		(((n) & 0x3) << 2)
+#define STM32_MDMA_CTCR_SINC_MASK	GENMASK(1, 0)
+#define STM32_MDMA_CTCR_SINC(n)		((n) & STM32_MDMA_CTCR_SINC_MASK)
+#define STM32_MDMA_CTCR_CFG_MASK	(STM32_MDMA_CTCR_SINC_MASK \
+					| STM32_MDMA_CTCR_DINC_MASK \
+					| STM32_MDMA_CTCR_SINCOS_MASK \
+					| STM32_MDMA_CTCR_DINCOS_MASK \
+					| STM32_MDMA_CTCR_LEN2_MSK \
+					| STM32_MDMA_CTCR_TRGM_MSK)
+
+/* MDMA Channel x block number of data register */
+#define STM32_MDMA_CBNDTR(x)		(0x54 + 0x40 * (x))
+#define STM32_MDMA_CBNDTR_BRC_MK	GENMASK(31, 20)
+#define STM32_MDMA_CBNDTR_BRC(n)	(((n) & 0xfff) << 20)
+#define STM32_MDMA_CBNDTR_BRC_GET(n)	(((n) & STM32_MDMA_CBNDTR_BRC_MK) >> 20)
+#define STM32_MDMA_CBNDTR_BRDUM		BIT(19)
+#define STM32_MDMA_CBNDTR_BRSUM		BIT(18)
+#define STM32_MDMA_CBNDTR_BNDT_MASK	GENMASK(16, 0)
+#define STM32_MDMA_CBNDTR_BNDT(n)	((n) & STM32_MDMA_CBNDTR_BNDT_MASK)
+
+/* MDMA Channel x source address register */
+#define STM32_MDMA_CSAR(x)		(0x58 + 0x40 * (x))
+
+/* MDMA Channel x destination address register */
+#define STM32_MDMA_CDAR(x)		(0x5C + 0x40 * (x))
+
+/* MDMA Channel x block repeat address update register */
+#define STM32_MDMA_CBRUR(x)		(0x60 + 0x40 * (x))
+#define STM32_MDMA_CBRUR_DUV_MASK	GENMASK(31, 16)
+#define STM32_MDMA_CBRUR_DUV(n)		(((n) & 0xffff) << 16)
+#define STM32_MDMA_CBRUR_SUV_MASK	GENMASK(15, 0)
+#define STM32_MDMA_CBRUR_SUV(n)		((n) & STM32_MDMA_CBRUR_SUV_MASK)
+
+/* MDMA Channel x link address register */
+#define STM32_MDMA_CLAR(x)		(0x64 + 0x40 * (x))
+
+/* MDMA Channel x trigger and bus selection register */
+#define STM32_MDMA_CTBR(x)		(0x68 + 0x40 * (x))
+#define STM32_MDMA_CTBR_DBUS		BIT(17)
+#define STM32_MDMA_CTBR_SBUS		BIT(16)
+#define STM32_MDMA_CTBR_TSEL_MASK	GENMASK(7, 0)
+#define STM32_MDMA_CTBR_TSEL(n)	((n) & STM32_MDMA_CTBR_TSEL_MASK)
+
+/* MDMA Channel x mask address register */
+#define STM32_MDMA_CMAR(x)		(0x70 + 0x40 * (x))
+
+/* MDMA Channel x mask data register */
+#define STM32_MDMA_CMDR(x)		(0x74 + 0x40 * (x))
+
+#define STM32_MDMA_MAX_BUF_LEN		128
+#define STM32_MDMA_MAX_BLOCK_LEN	65536
+#define STM32_MDMA_MAX_CHANNELS		63
+#define STM32_MDMA_MAX_REQUESTS		256
+#define STM32_MDMA_MAX_BURST		128
+#define STM32_MDMA_VERY_HIGH_PRIORITY	0x11
+
+enum stm32_mdma_trigger_mode {
+	STM32_MDMA_BUFFER,
+	STM32_MDMA_BLOCK,
+	STM32_MDMA_BLOCK_REP,
+	STM32_MDMA_LINKED_LIST,
+};
+
+enum stm32_mdma_width {
+	STM32_MDMA_BYTE,
+	STM32_MDMA_HALF_WORD,
+	STM32_MDMA_WORD,
+	STM32_MDMA_DOUBLE_WORD,
+};
+
+enum stm32_mdma_inc_mode {
+	STM32_MDMA_FIXED = 0,
+	STM32_MDMA_INC = 2,
+	STM32_MDMA_DEC = 3,
+};
+
+struct stm32_mdma_chan_config {
+	u32 request;
+	u32 priority_level;
+	u32 transfer_config;
+	u32 mask_addr;
+	u32 mask_data;
+};
+
+struct stm32_mdma_hwdesc {
+	u32 ctcr;
+	u32 cbndtr;
+	u32 csar;
+	u32 cdar;
+	u32 cbrur;
+	u32 clar;
+	u32 ctbr;
+	u32 dummy;
+	u32 cmar;
+	u32 cmdr;
+} __aligned(64);
+
+struct stm32_mdma_desc {
+	struct virt_dma_desc vdesc;
+	u32 ccr;
+	struct stm32_mdma_hwdesc *hwdesc;
+	dma_addr_t hwdesc_phys;
+	bool cyclic;
+	u32 count;
+};
+
+struct stm32_mdma_chan {
+	struct virt_dma_chan vchan;
+	struct dma_pool *desc_pool;
+	u32 id;
+	struct stm32_mdma_desc *desc;
+	u32 curr_hwdesc;
+	struct dma_slave_config dma_config;
+	struct stm32_mdma_chan_config chan_config;
+	bool busy;
+	u32 mem_burst;
+	u32 mem_width;
+};
+
+struct stm32_mdma_device {
+	struct dma_device ddev;
+	void __iomem *base;
+	struct clk *clk;
+	int irq;
+	struct reset_control *rst;
+	u32 nr_channels;
+	u32 nr_requests;
+	u32 nr_ahb_addr_masks;
+	struct stm32_mdma_chan chan[STM32_MDMA_MAX_CHANNELS];
+	u32 ahb_addr_masks[];
+};
+
+static struct stm32_mdma_device *stm32_mdma_get_dev(
+	struct stm32_mdma_chan *chan)
+{
+	return container_of(chan->vchan.chan.device, struct stm32_mdma_device,
+			    ddev);
+}
+
+static struct stm32_mdma_chan *to_stm32_mdma_chan(struct dma_chan *c)
+{
+	return container_of(c, struct stm32_mdma_chan, vchan.chan);
+}
+
+static struct stm32_mdma_desc *to_stm32_mdma_desc(struct virt_dma_desc *vdesc)
+{
+	return container_of(vdesc, struct stm32_mdma_desc, vdesc);
+}
+
+static struct device *chan2dev(struct stm32_mdma_chan *chan)
+{
+	return &chan->vchan.chan.dev->device;
+}
+
+static struct device *mdma2dev(struct stm32_mdma_device *mdma_dev)
+{
+	return mdma_dev->ddev.dev;
+}
+
+static u32 stm32_mdma_read(struct stm32_mdma_device *dmadev, u32 reg)
+{
+	return readl_relaxed(dmadev->base + reg);
+}
+
+static void stm32_mdma_write(struct stm32_mdma_device *dmadev, u32 reg, u32 val)
+{
+	writel_relaxed(val, dmadev->base + reg);
+}
+
+static void stm32_mdma_set_bits(struct stm32_mdma_device *dmadev, u32 reg,
+				u32 mask)
+{
+	void __iomem *addr = dmadev->base + reg;
+
+	writel_relaxed(readl_relaxed(addr) | mask, addr);
+}
+
+static void stm32_mdma_clr_bits(struct stm32_mdma_device *dmadev, u32 reg,
+				u32 mask)
+{
+	void __iomem *addr = dmadev->base + reg;
+
+	writel_relaxed(readl_relaxed(addr) & ~mask, addr);
+}
+
+static struct stm32_mdma_desc *stm32_mdma_alloc_desc(
+		struct stm32_mdma_chan *chan, u32 count)
+{
+	struct stm32_mdma_desc *desc;
+
+	desc = kzalloc(sizeof(*desc), GFP_NOWAIT);
+	if (!desc)
+		return NULL;
+
+	desc->hwdesc = dma_pool_alloc(chan->desc_pool, GFP_NOWAIT,
+				      &desc->hwdesc_phys);
+	if (!desc->hwdesc) {
+		dev_err(chan2dev(chan), "Failed to allocate descriptor\n");
+		kfree(desc);
+		return NULL;
+	}
+
+	desc->count = count;
+
+	return desc;
+}
+
+static void stm32_mdma_desc_free(struct virt_dma_desc *vdesc)
+{
+	struct stm32_mdma_desc *desc = to_stm32_mdma_desc(vdesc);
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(vdesc->tx.chan);
+
+	dma_pool_free(chan->desc_pool, desc->hwdesc, desc->hwdesc_phys);
+	kfree(desc);
+}
+
+static int stm32_mdma_get_width(struct stm32_mdma_chan *chan,
+				enum dma_slave_buswidth width)
+{
+	switch (width) {
+	case DMA_SLAVE_BUSWIDTH_1_BYTE:
+	case DMA_SLAVE_BUSWIDTH_2_BYTES:
+	case DMA_SLAVE_BUSWIDTH_4_BYTES:
+	case DMA_SLAVE_BUSWIDTH_8_BYTES:
+		return ffs(width) - 1;
+	default:
+		dev_err(chan2dev(chan), "Dma bus width not supported\n");
+		return -EINVAL;
+	}
+}
+
+static enum dma_slave_buswidth stm32_mdma_get_max_width(u32 buf_len, u32 tlen)
+{
+	enum dma_slave_buswidth max_width = DMA_SLAVE_BUSWIDTH_8_BYTES;
+
+	for (max_width = DMA_SLAVE_BUSWIDTH_8_BYTES;
+	     max_width > DMA_SLAVE_BUSWIDTH_1_BYTE;
+	     max_width >>= 1) {
+		if (((buf_len % max_width) == 0) && (tlen >= max_width))
+			break;
+	}
+
+	return max_width;
+}
+
+static u32 stm32_mdma_get_best_burst(u32 buf_len, u32 tlen, u32 max_burst,
+				     enum dma_slave_buswidth width)
+{
+	u32 best_burst = max_burst;
+	u32 burst_len = best_burst * width;
+
+	while ((burst_len > 0) && (tlen % burst_len)) {
+		best_burst = best_burst >> 1;
+		burst_len = best_burst * width;
+	}
+
+	return (best_burst > 0) ? best_burst : 1;
+}
+
+static int stm32_mdma_disable_chan(struct stm32_mdma_chan *chan)
+{
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	u32 ccr, cisr, id, reg;
+	int ret;
+
+	id = chan->id;
+	reg = STM32_MDMA_CCR(id);
+
+	/* Disable interrupts */
+	stm32_mdma_clr_bits(dmadev, reg, STM32_MDMA_CCR_IRQ_MASK);
+
+	ccr = stm32_mdma_read(dmadev, reg);
+	if (ccr & STM32_MDMA_CCR_EN) {
+		stm32_mdma_clr_bits(dmadev, reg, STM32_MDMA_CCR_EN);
+
+		/* Ensure that any ongoing transfer has been completed */
+		ret = readl_relaxed_poll_timeout_atomic(
+				dmadev->base + STM32_MDMA_CISR(id), cisr,
+				(cisr & STM32_MDMA_CISR_CTCIF), 10, 1000);
+		if (ret) {
+			dev_err(chan2dev(chan), "%s: timeout!\n", __func__);
+			return -EBUSY;
+		}
+	}
+
+	return 0;
+}
+
+static void stm32_mdma_stop(struct stm32_mdma_chan *chan)
+{
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	u32 status;
+	int ret;
+
+	/* Disable DMA */
+	ret = stm32_mdma_disable_chan(chan);
+	if (ret < 0)
+		return;
+
+	/* Clear interrupt status if it is there */
+	status = stm32_mdma_read(dmadev, STM32_MDMA_CISR(chan->id));
+	if (status) {
+		dev_dbg(chan2dev(chan), "%s(): clearing interrupt: 0x%08x\n",
+			__func__, status);
+		stm32_mdma_set_bits(dmadev, STM32_MDMA_CIFCR(chan->id), status);
+	}
+
+	chan->busy = false;
+}
+
+static void stm32_mdma_set_bus(struct stm32_mdma_device *dmadev, u32 *ctbr,
+			       u32 ctbr_mask, u32 src_addr)
+{
+	u32 mask;
+	int i;
+
+	/* Check if memory device is on AHB or AXI */
+	*ctbr &= ~ctbr_mask;
+	mask = src_addr & 0xF0000000;
+	for (i = 0; i < dmadev->nr_ahb_addr_masks; i++) {
+		if (mask == dmadev->ahb_addr_masks[i]) {
+			*ctbr |= ctbr_mask;
+			break;
+		}
+	}
+}
+
+static int stm32_mdma_set_xfer_param(struct stm32_mdma_chan *chan,
+				     enum dma_transfer_direction direction,
+				     u32 *mdma_ccr, u32 *mdma_ctcr,
+				     u32 *mdma_ctbr, u32 buf_len)
+{
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	struct stm32_mdma_chan_config *chan_config = &chan->chan_config;
+	enum dma_slave_buswidth src_addr_width, dst_addr_width;
+	phys_addr_t src_addr, dst_addr;
+	int src_bus_width, dst_bus_width;
+	u32 src_maxburst, dst_maxburst, src_best_burst, dst_best_burst;
+	u32 ccr, ctcr, ctbr, tlen;
+
+	src_addr_width = chan->dma_config.src_addr_width;
+	dst_addr_width = chan->dma_config.dst_addr_width;
+	src_maxburst = chan->dma_config.src_maxburst;
+	dst_maxburst = chan->dma_config.dst_maxburst;
+
+	ccr = stm32_mdma_read(dmadev, STM32_MDMA_CCR(chan->id));
+	ctcr = stm32_mdma_read(dmadev, STM32_MDMA_CTCR(chan->id));
+	ctbr = stm32_mdma_read(dmadev, STM32_MDMA_CTBR(chan->id));
+
+	/* Enable HW request mode */
+	ctcr &= ~STM32_MDMA_CTCR_SWRM;
+
+	/* Set DINC, SINC, DINCOS, SINCOS, TRGM and TLEN retrieve from DT */
+	ctcr &= ~STM32_MDMA_CTCR_CFG_MASK;
+	ctcr |= chan_config->transfer_config & STM32_MDMA_CTCR_CFG_MASK;
+
+	/*
+	 * For buffer transfer length (TLEN) we have to set
+	 * the number of bytes - 1 in CTCR register
+	 */
+	tlen = STM32_MDMA_CTCR_LEN2_GET(ctcr);
+	ctcr &= ~STM32_MDMA_CTCR_LEN2_MSK;
+	ctcr |= STM32_MDMA_CTCR_TLEN((tlen - 1));
+
+	/* Check burst size constraints */
+	if (src_maxburst * src_addr_width > STM32_MDMA_MAX_BURST ||
+	    dst_maxburst * dst_addr_width > STM32_MDMA_MAX_BURST) {
+		dev_err(chan2dev(chan),
+			"burst size * bus width higher than %d bytes\n",
+			STM32_MDMA_MAX_BURST);
+		return -EINVAL;
+	}
+
+	if ((!is_power_of_2(src_maxburst) && src_maxburst > 0) ||
+	    (!is_power_of_2(dst_maxburst) && dst_maxburst > 0)) {
+		dev_err(chan2dev(chan), "burst size must be a power of 2\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * Configure channel control:
+	 * - Clear SW request as in this case this is a HW one
+	 * - Clear WEX, HEX and BEX bits
+	 * - Set priority level
+	 */
+	ccr &= ~(STM32_MDMA_CCR_SWRQ | STM32_MDMA_CCR_WEX | STM32_MDMA_CCR_HEX |
+		 STM32_MDMA_CCR_BEX | STM32_MDMA_CCR_PL_MASK);
+	ccr |= STM32_MDMA_CCR_PL(chan_config->priority_level);
+
+	/* Configure Trigger selection */
+	ctbr &= ~STM32_MDMA_CTBR_TSEL_MASK;
+	ctbr |= STM32_MDMA_CTBR_TSEL(chan_config->request);
+
+	switch (direction) {
+	case DMA_MEM_TO_DEV:
+		/* Set device data size */
+		dst_bus_width = stm32_mdma_get_width(chan, dst_addr_width);
+		if (dst_bus_width < 0)
+			return dst_bus_width;
+		ctcr &= ~STM32_MDMA_CTCR_DSIZE_MASK;
+		ctcr |= STM32_MDMA_CTCR_DSIZE(dst_bus_width);
+
+		/* Set device burst value */
+		dst_best_burst = stm32_mdma_get_best_burst(buf_len, tlen,
+							   dst_maxburst,
+							   dst_addr_width);
+		chan->mem_burst = dst_best_burst;
+		ctcr &= ~STM32_MDMA_CTCR_DBURST_MASK;
+		ctcr |= STM32_MDMA_CTCR_DBURST((ilog2(dst_best_burst)));
+
+		/* Set memory data size */
+		src_addr_width = stm32_mdma_get_max_width(buf_len, tlen);
+		chan->mem_width = src_addr_width;
+		src_bus_width = stm32_mdma_get_width(chan, src_addr_width);
+		if (src_bus_width < 0)
+			return src_bus_width;
+		ctcr &= ~STM32_MDMA_CTCR_SSIZE_MASK |
+			STM32_MDMA_CTCR_SINCOS_MASK;
+		ctcr |= STM32_MDMA_CTCR_SSIZE(src_bus_width) |
+			STM32_MDMA_CTCR_SINCOS(src_bus_width);
+
+		/* Set memory burst value */
+		src_maxburst = STM32_MDMA_MAX_BUF_LEN / src_addr_width;
+		src_best_burst = stm32_mdma_get_best_burst(buf_len, tlen,
+							   src_maxburst,
+							   src_addr_width);
+		chan->mem_burst = src_best_burst;
+		ctcr &= ~STM32_MDMA_CTCR_SBURST_MASK;
+		ctcr |= STM32_MDMA_CTCR_SBURST((ilog2(src_best_burst)));
+
+		/* Select bus */
+		dst_addr = chan->dma_config.dst_addr;
+		stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_DBUS,
+				   dst_addr);
+
+		/* Set destination address */
+		stm32_mdma_write(dmadev, STM32_MDMA_CDAR(chan->id), dst_addr);
+		break;
+
+	case DMA_DEV_TO_MEM:
+		/* Set device data size */
+		src_bus_width = stm32_mdma_get_width(chan, src_addr_width);
+		if (src_bus_width < 0)
+			return src_bus_width;
+		ctcr &= ~STM32_MDMA_CTCR_SSIZE_MASK;
+		ctcr |= STM32_MDMA_CTCR_SSIZE(src_bus_width);
+
+		/* Set device burst value */
+		src_best_burst = stm32_mdma_get_best_burst(buf_len, tlen,
+							   src_maxburst,
+							   src_addr_width);
+		ctcr &= ~STM32_MDMA_CTCR_SBURST_MASK;
+		ctcr |= STM32_MDMA_CTCR_SBURST((ilog2(src_best_burst)));
+
+		/* Set memory data size */
+		dst_addr_width = stm32_mdma_get_max_width(buf_len, tlen);
+		chan->mem_width = dst_addr_width;
+		dst_bus_width = stm32_mdma_get_width(chan, dst_addr_width);
+		if (dst_bus_width < 0)
+			return dst_bus_width;
+		ctcr &= ~(STM32_MDMA_CTCR_DSIZE_MASK |
+			STM32_MDMA_CTCR_DINCOS_MASK);
+		ctcr |= STM32_MDMA_CTCR_DSIZE(dst_bus_width) |
+			STM32_MDMA_CTCR_DINCOS(dst_bus_width);
+
+		/* Set memory burst value */
+		dst_maxburst = STM32_MDMA_MAX_BUF_LEN / dst_addr_width;
+		dst_best_burst = stm32_mdma_get_best_burst(buf_len, tlen,
+							   dst_maxburst,
+							   dst_addr_width);
+		ctcr &= ~STM32_MDMA_CTCR_DBURST_MASK;
+		ctcr |= STM32_MDMA_CTCR_DBURST((ilog2(dst_best_burst)));
+
+		/* Select bus */
+		src_addr = chan->dma_config.src_addr;
+		stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_SBUS,
+				   src_addr);
+
+		/* Set source address */
+		stm32_mdma_write(dmadev, STM32_MDMA_CSAR(chan->id), src_addr);
+		break;
+
+	default:
+		dev_err(chan2dev(chan), "Dma direction is not supported\n");
+		return -EINVAL;
+	}
+
+	*mdma_ccr = ccr;
+	*mdma_ctcr = ctcr;
+	*mdma_ctbr = ctbr;
+
+	return 0;
+}
+
+static void stm32_mdma_dump_hwdesc(struct stm32_mdma_chan *chan,
+				   struct stm32_mdma_hwdesc *hwdesc)
+{
+	dev_dbg(chan2dev(chan), "hwdesc:  0x%08x\n", (unsigned int)hwdesc);
+	dev_dbg(chan2dev(chan), "CTCR:    0x%08x\n", hwdesc->ctcr);
+	dev_dbg(chan2dev(chan), "CBNDTR:  0x%08x\n", hwdesc->cbndtr);
+	dev_dbg(chan2dev(chan), "CSAR:    0x%08x\n", hwdesc->csar);
+	dev_dbg(chan2dev(chan), "CDAR:    0x%08x\n", hwdesc->cdar);
+	dev_dbg(chan2dev(chan), "CBRUR:   0x%08x\n", hwdesc->cbrur);
+	dev_dbg(chan2dev(chan), "CLAR:    0x%08x\n", hwdesc->clar);
+	dev_dbg(chan2dev(chan), "CTBR:    0x%08x\n", hwdesc->ctbr);
+	dev_dbg(chan2dev(chan), "CMAR:    0x%08x\n", hwdesc->cmar);
+	dev_dbg(chan2dev(chan), "CMDR:    0x%08x\n\n", hwdesc->cmdr);
+}
+
+static void stm32_mdma_setup_hwdesc(struct stm32_mdma_chan *chan,
+				    struct stm32_mdma_desc *desc,
+				    enum dma_transfer_direction dir, u32 count,
+				    dma_addr_t src_addr, dma_addr_t dst_addr,
+				    u32 len, u32 ctcr, u32 ctbr, bool is_last,
+				    bool is_first, bool is_cyclic)
+{
+	struct stm32_mdma_chan_config *config = &chan->chan_config;
+	struct stm32_mdma_hwdesc *hwdesc;
+	u32 next = count + 1;
+
+	hwdesc = &desc->hwdesc[count];
+	hwdesc->ctcr = ctcr;
+	hwdesc->cbndtr &= ~(STM32_MDMA_CBNDTR_BRC_MK |
+			STM32_MDMA_CBNDTR_BRDUM |
+			STM32_MDMA_CBNDTR_BRSUM |
+			STM32_MDMA_CBNDTR_BNDT_MASK);
+	hwdesc->cbndtr |= STM32_MDMA_CBNDTR_BNDT(len);
+	hwdesc->csar = src_addr;
+	hwdesc->cdar = dst_addr;
+	hwdesc->cbrur = 0;
+	hwdesc->clar = desc->hwdesc_phys + next * sizeof(*hwdesc);
+	hwdesc->ctbr = ctbr;
+	hwdesc->cmar = config->mask_addr;
+	hwdesc->cmdr = config->mask_data;
+
+	if (is_last) {
+		if (is_cyclic)
+			hwdesc->clar = desc->hwdesc_phys;
+		else
+			hwdesc->clar = 0;
+	}
+
+	stm32_mdma_dump_hwdesc(chan, hwdesc);
+}
+
+static int stm32_mdma_setup_xfer(struct stm32_mdma_chan *chan,
+				 struct stm32_mdma_desc *desc,
+				 struct scatterlist *sgl, u32 sg_len,
+				 enum dma_transfer_direction direction)
+{
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	struct dma_slave_config *dma_config = &chan->dma_config;
+	struct scatterlist *sg;
+	dma_addr_t src_addr, dst_addr;
+	u32 ccr, ctcr, ctbr;
+	int i, ret = 0;
+
+	for_each_sg(sgl, sg, sg_len, i) {
+		if (sg_dma_len(sg) > STM32_MDMA_MAX_BLOCK_LEN) {
+			dev_err(chan2dev(chan), "Invalid block len\n");
+			return -EINVAL;
+		}
+
+		ret = stm32_mdma_set_xfer_param(chan, direction, &ccr, &ctcr,
+						&ctbr, sg_dma_len(sg));
+		if (ret < 0)
+			return ret;
+
+		if (direction == DMA_MEM_TO_DEV) {
+			src_addr = sg_dma_address(sg);
+			dst_addr = dma_config->dst_addr;
+			stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_SBUS,
+					   src_addr);
+		} else {
+			src_addr = dma_config->src_addr;
+			dst_addr = sg_dma_address(sg);
+			stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_DBUS,
+					   dst_addr);
+		}
+
+		stm32_mdma_setup_hwdesc(chan, desc, direction, i, src_addr,
+					dst_addr, sg_dma_len(sg), ctcr, ctbr,
+					i == sg_len - 1, i == 0, false);
+	}
+
+	/* Enable interrupts */
+	ccr &= ~STM32_MDMA_CCR_IRQ_MASK;
+	ccr |= STM32_MDMA_CCR_TEIE | STM32_MDMA_CCR_CTCIE;
+	if (sg_len > 1)
+		ccr |= STM32_MDMA_CCR_BTIE;
+	desc->ccr = ccr;
+
+	return 0;
+}
+
+static struct dma_async_tx_descriptor *
+stm32_mdma_prep_slave_sg(struct dma_chan *c, struct scatterlist *sgl,
+			 u32 sg_len, enum dma_transfer_direction direction,
+			 unsigned long flags, void *context)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	struct stm32_mdma_desc *desc;
+	int ret;
+
+	desc = stm32_mdma_alloc_desc(chan, sg_len);
+	if (!desc)
+		return NULL;
+
+	ret = stm32_mdma_setup_xfer(chan, desc, sgl, sg_len, direction);
+	if (ret < 0)
+		goto xfer_setup_err;
+
+	desc->cyclic = false;
+
+	return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
+
+xfer_setup_err:
+	dma_pool_free(chan->desc_pool, &desc->hwdesc, desc->hwdesc_phys);
+	kfree(desc);
+	return NULL;
+}
+
+static struct dma_async_tx_descriptor *
+stm32_mdma_prep_dma_cyclic(struct dma_chan *c, dma_addr_t buf_addr,
+			   size_t buf_len, size_t period_len,
+			   enum dma_transfer_direction direction,
+			   unsigned long flags)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	struct dma_slave_config *dma_config = &chan->dma_config;
+	struct stm32_mdma_desc *desc;
+	dma_addr_t src_addr, dst_addr;
+	u32 ccr, ctcr, ctbr, count;
+	int i, ret;
+
+	if (!buf_len || !period_len || period_len > STM32_MDMA_MAX_BLOCK_LEN) {
+		dev_err(chan2dev(chan), "Invalid buffer/period len\n");
+		return NULL;
+	}
+
+	if (buf_len % period_len) {
+		dev_err(chan2dev(chan), "buf_len not multiple of period_len\n");
+		return NULL;
+	}
+
+	/*
+	 * We allow to take more number of requests till DMA is
+	 * not started. The driver will loop over all requests.
+	 * Once DMA is started then new requests can be queued only after
+	 * terminating the DMA.
+	 */
+	if (chan->busy) {
+		dev_err(chan2dev(chan), "Request not allowed when dma busy\n");
+		return NULL;
+	}
+
+	count = buf_len / period_len;
+
+	desc = stm32_mdma_alloc_desc(chan, count);
+	if (!desc)
+		return NULL;
+
+	ret = stm32_mdma_set_xfer_param(chan, direction, &ccr, &ctcr, &ctbr,
+					period_len);
+	if (ret < 0)
+		goto xfer_setup_err;
+
+	/* Enable interrupts */
+	ccr &= ~STM32_MDMA_CCR_IRQ_MASK;
+	ccr |= STM32_MDMA_CCR_TEIE | STM32_MDMA_CCR_CTCIE | STM32_MDMA_CCR_BTIE;
+	desc->ccr = ccr;
+
+	/* Select bus */
+	if (direction == DMA_MEM_TO_DEV) {
+		src_addr = buf_addr;
+		stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_SBUS,
+				   src_addr);
+	} else {
+		dst_addr = buf_addr;
+		stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_DBUS,
+				   dst_addr);
+	}
+
+	/* Configure hwdesc list */
+	for (i = 0; i < count; i++) {
+		if (direction == DMA_MEM_TO_DEV) {
+			src_addr = buf_addr + i * period_len;
+			dst_addr = dma_config->dst_addr;
+		} else {
+			src_addr = dma_config->src_addr;
+			dst_addr = buf_addr + i * period_len;
+		}
+
+		stm32_mdma_setup_hwdesc(chan, desc, direction, i, src_addr,
+					dst_addr, period_len, ctcr, ctbr,
+					i == count - 1, i == 0, true);
+	}
+
+	desc->cyclic = true;
+
+	return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
+
+xfer_setup_err:
+	dma_pool_free(chan->desc_pool, &desc->hwdesc, desc->hwdesc_phys);
+	kfree(desc);
+	return NULL;
+}
+
+static struct dma_async_tx_descriptor *
+stm32_mdma_prep_dma_memcpy(struct dma_chan *c, dma_addr_t dest, dma_addr_t src,
+			   size_t len, unsigned long flags)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	enum dma_slave_buswidth max_width;
+	struct stm32_mdma_desc *desc;
+	struct stm32_mdma_hwdesc *hwdesc;
+	u32 ccr, ctcr, ctbr, cbndtr, count, max_burst, mdma_burst;
+	u32 best_burst, tlen;
+	size_t xfer_count, offset;
+	int i;
+
+	count = DIV_ROUND_UP(len, STM32_MDMA_MAX_BLOCK_LEN);
+	desc = stm32_mdma_alloc_desc(chan, count);
+	if (!desc)
+		return NULL;
+
+	ccr = stm32_mdma_read(dmadev, STM32_MDMA_CCR(chan->id));
+	ctcr = stm32_mdma_read(dmadev, STM32_MDMA_CTCR(chan->id));
+	ctbr = stm32_mdma_read(dmadev, STM32_MDMA_CTBR(chan->id));
+	cbndtr = stm32_mdma_read(dmadev, STM32_MDMA_CBNDTR(chan->id));
+
+	/* Enable sw req, some interrupts and clear other bits */
+	ccr &= ~(STM32_MDMA_CCR_WEX | STM32_MDMA_CCR_HEX |
+		 STM32_MDMA_CCR_BEX | STM32_MDMA_CCR_PL_MASK |
+		 STM32_MDMA_CCR_IRQ_MASK);
+	ccr |= STM32_MDMA_CCR_TEIE;
+
+	/* Enable SW request mode, dest/src inc and clear other bits */
+	ctcr &= ~(STM32_MDMA_CTCR_BWM | STM32_MDMA_CTCR_TRGM_MSK |
+		  STM32_MDMA_CTCR_PAM_MASK | STM32_MDMA_CTCR_PKE |
+		  STM32_MDMA_CTCR_TLEN_MSK | STM32_MDMA_CTCR_DBURST_MASK |
+		  STM32_MDMA_CTCR_SBURST_MASK | STM32_MDMA_CTCR_DINCOS_MASK |
+		  STM32_MDMA_CTCR_SINCOS_MASK | STM32_MDMA_CTCR_DSIZE_MASK |
+		  STM32_MDMA_CTCR_SSIZE_MASK | STM32_MDMA_CTCR_DINC_MASK |
+		  STM32_MDMA_CTCR_SINC_MASK);
+	ctcr |= STM32_MDMA_CTCR_SWRM | STM32_MDMA_CTCR_SINC(STM32_MDMA_INC) |
+		STM32_MDMA_CTCR_DINC(STM32_MDMA_INC);
+
+	/* Reset HW request */
+	ctbr &= ~STM32_MDMA_CTBR_TSEL_MASK;
+
+	/* Select bus */
+	stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_SBUS, src);
+	stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_DBUS, dest);
+
+	/* Clear CBNDTR registers */
+	cbndtr &= ~(STM32_MDMA_CBNDTR_BRC_MK | STM32_MDMA_CBNDTR_BRDUM |
+			STM32_MDMA_CBNDTR_BRSUM | STM32_MDMA_CBNDTR_BNDT_MASK);
+
+	if (len <= STM32_MDMA_MAX_BLOCK_LEN) {
+		cbndtr |= STM32_MDMA_CBNDTR_BNDT(len);
+		if (len <= STM32_MDMA_MAX_BUF_LEN) {
+			/* Setup a buffer transfer */
+			tlen = len;
+			ccr |= STM32_MDMA_CCR_TCIE | STM32_MDMA_CCR_CTCIE;
+			ctcr |= STM32_MDMA_CTCR_TRGM(STM32_MDMA_BUFFER);
+			ctcr |= STM32_MDMA_CTCR_TLEN((tlen - 1));
+		} else {
+			/* Setup a block transfer */
+			tlen = STM32_MDMA_MAX_BUF_LEN;
+			ccr |= STM32_MDMA_CCR_BTIE | STM32_MDMA_CCR_CTCIE;
+			ctcr |= STM32_MDMA_CTCR_TRGM(STM32_MDMA_BLOCK);
+			ctcr |= STM32_MDMA_CTCR_TLEN(tlen - 1);
+		}
+
+		/* Set best burst size */
+		max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+		max_burst = tlen / max_width;
+		best_burst = stm32_mdma_get_best_burst(len, tlen, max_burst,
+						       max_width);
+
+		mdma_burst = ilog2(best_burst);
+
+		ctcr |= STM32_MDMA_CTCR_DBURST(mdma_burst) |
+			STM32_MDMA_CTCR_SBURST(mdma_burst);
+
+		/* Prepare hardware descriptor */
+		hwdesc = desc->hwdesc;
+		hwdesc->ctcr = ctcr;
+		hwdesc->cbndtr = cbndtr;
+		hwdesc->csar = src;
+		hwdesc->cdar = dest;
+		hwdesc->cbrur = 0;
+		hwdesc->clar = 0;
+		hwdesc->ctbr = ctbr;
+		hwdesc->cmar = 0;
+		hwdesc->cmdr = 0;
+
+		stm32_mdma_dump_hwdesc(chan, hwdesc);
+	} else {
+		/* Setup a LLI transfer */
+		ctcr |= STM32_MDMA_CTCR_TRGM(STM32_MDMA_LINKED_LIST) |
+			STM32_MDMA_CTCR_TLEN((STM32_MDMA_MAX_BUF_LEN - 1));
+		ccr |= STM32_MDMA_CCR_BTIE | STM32_MDMA_CCR_CTCIE;
+		tlen = STM32_MDMA_MAX_BUF_LEN;
+
+		for (i = 0, offset = 0; offset < len;
+		     i++, offset += xfer_count) {
+			xfer_count = min_t(size_t, len - offset,
+					   STM32_MDMA_MAX_BLOCK_LEN);
+
+			/* Set best burst size */
+			max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+			max_burst = STM32_MDMA_MAX_BUF_LEN / max_width;
+			best_burst = stm32_mdma_get_best_burst(xfer_count, tlen,
+							       max_burst,
+							       max_width);
+			mdma_burst = ilog2(best_burst);
+
+			ctcr &= ~(STM32_MDMA_CTCR_DBURST_MASK |
+				  STM32_MDMA_CTCR_SBURST_MASK);
+			ctcr |= STM32_MDMA_CTCR_DBURST(mdma_burst) |
+				STM32_MDMA_CTCR_SBURST(mdma_burst);
+
+			/* Prepare hardware descriptor */
+			stm32_mdma_setup_hwdesc(chan, desc, DMA_MEM_TO_MEM, i,
+						src + offset, dest + offset,
+						xfer_count, ctcr, ctbr,
+						i == count - 1, i == 0, false);
+		}
+	}
+
+	desc->ccr = ccr;
+
+	desc->cyclic = false;
+
+	return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
+}
+
+static void stm32_mdma_dump_reg(struct stm32_mdma_chan *chan)
+{
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+
+	dev_dbg(chan2dev(chan), "CCR:     0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CCR(chan->id)));
+	dev_dbg(chan2dev(chan), "CTCR:    0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CTCR(chan->id)));
+	dev_dbg(chan2dev(chan), "CBNDTR:  0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CBNDTR(chan->id)));
+	dev_dbg(chan2dev(chan), "CSAR:    0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CSAR(chan->id)));
+	dev_dbg(chan2dev(chan), "CDAR:    0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CDAR(chan->id)));
+	dev_dbg(chan2dev(chan), "CBRUR:   0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CBRUR(chan->id)));
+	dev_dbg(chan2dev(chan), "CLAR:    0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CLAR(chan->id)));
+	dev_dbg(chan2dev(chan), "CTBR:    0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CTBR(chan->id)));
+	dev_dbg(chan2dev(chan), "CMAR:    0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CMAR(chan->id)));
+	dev_dbg(chan2dev(chan), "CMDR:    0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CMDR(chan->id)));
+}
+
+static void stm32_mdma_start_transfer(struct stm32_mdma_chan *chan)
+{
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	struct virt_dma_desc *vdesc;
+	struct stm32_mdma_hwdesc *hwdesc;
+	u32 id = chan->id;
+	u32 status, reg;
+
+	vdesc = vchan_next_desc(&chan->vchan);
+	if (!vdesc) {
+		chan->desc = NULL;
+		return;
+	}
+
+	chan->desc = to_stm32_mdma_desc(vdesc);
+	hwdesc = chan->desc->hwdesc;
+	chan->curr_hwdesc = 0;
+
+	stm32_mdma_write(dmadev, STM32_MDMA_CCR(id), chan->desc->ccr);
+	stm32_mdma_write(dmadev, STM32_MDMA_CTCR(id), hwdesc->ctcr);
+	stm32_mdma_write(dmadev, STM32_MDMA_CBNDTR(id), hwdesc->cbndtr);
+	stm32_mdma_write(dmadev, STM32_MDMA_CSAR(id), hwdesc->csar);
+	stm32_mdma_write(dmadev, STM32_MDMA_CDAR(id), hwdesc->cdar);
+	stm32_mdma_write(dmadev, STM32_MDMA_CBRUR(id), hwdesc->cbrur);
+	stm32_mdma_write(dmadev, STM32_MDMA_CLAR(id), hwdesc->clar);
+	stm32_mdma_write(dmadev, STM32_MDMA_CTBR(id), hwdesc->ctbr);
+	stm32_mdma_write(dmadev, STM32_MDMA_CMAR(id), hwdesc->cmar);
+	stm32_mdma_write(dmadev, STM32_MDMA_CMDR(id), hwdesc->cmdr);
+
+	/* Clear interrupt status if it is there */
+	status = stm32_mdma_read(dmadev, STM32_MDMA_CISR(id));
+	if (status)
+		stm32_mdma_set_bits(dmadev, STM32_MDMA_CIFCR(id), status);
+
+	stm32_mdma_dump_reg(chan);
+
+	/* Start DMA */
+	stm32_mdma_set_bits(dmadev, STM32_MDMA_CCR(id), STM32_MDMA_CCR_EN);
+
+	/* Set SW request in case of MEM2MEM transfer */
+	if (hwdesc->ctcr & STM32_MDMA_CTCR_SWRM) {
+		reg = STM32_MDMA_CCR(id);
+		stm32_mdma_set_bits(dmadev, reg, STM32_MDMA_CCR_SWRQ);
+	}
+
+	chan->busy = true;
+
+	dev_dbg(chan2dev(chan), "vchan %p: started\n", &chan->vchan);
+}
+
+static void stm32_mdma_issue_pending(struct dma_chan *c)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	unsigned long flags;
+
+	spin_lock_irqsave(&chan->vchan.lock, flags);
+
+	if (!vchan_issue_pending(&chan->vchan))
+		goto end;
+
+	dev_dbg(chan2dev(chan), "vchan %p: issued\n", &chan->vchan);
+
+	if (!chan->desc && !chan->busy)
+		stm32_mdma_start_transfer(chan);
+
+end:
+	spin_unlock_irqrestore(&chan->vchan.lock, flags);
+}
+
+static int stm32_mdma_pause(struct dma_chan *c)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&chan->vchan.lock, flags);
+	ret = stm32_mdma_disable_chan(chan);
+	spin_unlock_irqrestore(&chan->vchan.lock, flags);
+
+	if (!ret)
+		dev_dbg(chan2dev(chan), "vchan %p: pause\n", &chan->vchan);
+
+	return ret;
+}
+
+static int stm32_mdma_resume(struct dma_chan *c)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	struct stm32_mdma_hwdesc *hwdesc;
+	unsigned long flags;
+	u32 status, reg;
+
+	hwdesc = &chan->desc->hwdesc[chan->curr_hwdesc];
+
+	spin_lock_irqsave(&chan->vchan.lock, flags);
+
+	/* Re-configure control register */
+	stm32_mdma_write(dmadev, STM32_MDMA_CCR(chan->id), chan->desc->ccr);
+
+	/* Clear interrupt status if it is there */
+	status = stm32_mdma_read(dmadev, STM32_MDMA_CISR(chan->id));
+	if (status)
+		stm32_mdma_set_bits(dmadev, STM32_MDMA_CIFCR(chan->id), status);
+
+	stm32_mdma_dump_reg(chan);
+
+	/* Re-start DMA */
+	reg = STM32_MDMA_CCR(chan->id);
+	stm32_mdma_set_bits(dmadev, reg, STM32_MDMA_CCR_EN);
+
+	/* Set SW request in case of MEM2MEM transfer */
+	if (hwdesc->ctcr & STM32_MDMA_CTCR_SWRM)
+		stm32_mdma_set_bits(dmadev, reg, STM32_MDMA_CCR_SWRQ);
+
+	spin_unlock_irqrestore(&chan->vchan.lock, flags);
+
+	dev_dbg(chan2dev(chan), "vchan %p: resume\n", &chan->vchan);
+
+	return 0;
+}
+
+static int stm32_mdma_terminate_all(struct dma_chan *c)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	unsigned long flags;
+	LIST_HEAD(head);
+
+	spin_lock_irqsave(&chan->vchan.lock, flags);
+	if (chan->busy) {
+		stm32_mdma_stop(chan);
+		chan->desc = NULL;
+	}
+	vchan_get_all_descriptors(&chan->vchan, &head);
+	spin_unlock_irqrestore(&chan->vchan.lock, flags);
+
+	vchan_dma_desc_free_list(&chan->vchan, &head);
+
+	return 0;
+}
+
+static void stm32_mdma_synchronize(struct dma_chan *c)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+
+	vchan_synchronize(&chan->vchan);
+}
+
+static int stm32_mdma_slave_config(struct dma_chan *c,
+				   struct dma_slave_config *config)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+
+	memcpy(&chan->dma_config, config, sizeof(*config));
+
+	return 0;
+}
+
+static size_t stm32_mdma_desc_residue(struct stm32_mdma_chan *chan,
+				      struct stm32_mdma_desc *desc,
+				      u32 curr_hwdesc)
+{
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	struct stm32_mdma_hwdesc *hwdesc = desc->hwdesc;
+	u32 cbndtr, residue, modulo, burst_size;
+	int i;
+
+	residue = 0;
+	for (i = curr_hwdesc + 1; i < desc->count; i++) {
+		hwdesc = &desc->hwdesc[i];
+		residue += STM32_MDMA_CBNDTR_BNDT(hwdesc->cbndtr);
+	}
+	cbndtr = stm32_mdma_read(dmadev, STM32_MDMA_CBNDTR(chan->id));
+	residue += cbndtr & STM32_MDMA_CBNDTR_BNDT_MASK;
+
+	if (!chan->mem_burst)
+		return residue;
+
+	burst_size = chan->mem_burst * chan->mem_width;
+	modulo = residue % burst_size;
+	if (modulo)
+		residue = residue - modulo + burst_size;
+
+	return residue;
+}
+
+static enum dma_status stm32_mdma_tx_status(struct dma_chan *c,
+					    dma_cookie_t cookie,
+					    struct dma_tx_state *state)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	struct virt_dma_desc *vdesc;
+	enum dma_status status;
+	unsigned long flags;
+	u32 residue = 0;
+
+	status = dma_cookie_status(c, cookie, state);
+	if ((status == DMA_COMPLETE) || (!state))
+		return status;
+
+	spin_lock_irqsave(&chan->vchan.lock, flags);
+
+	vdesc = vchan_find_desc(&chan->vchan, cookie);
+	if (chan->desc && cookie == chan->desc->vdesc.tx.cookie)
+		residue = stm32_mdma_desc_residue(chan, chan->desc,
+						  chan->curr_hwdesc);
+	else if (vdesc)
+		residue = stm32_mdma_desc_residue(chan,
+						  to_stm32_mdma_desc(vdesc), 0);
+	dma_set_residue(state, residue);
+
+	spin_unlock_irqrestore(&chan->vchan.lock, flags);
+
+	return status;
+}
+
+static void stm32_mdma_xfer_end(struct stm32_mdma_chan *chan)
+{
+	list_del(&chan->desc->vdesc.node);
+	vchan_cookie_complete(&chan->desc->vdesc);
+	chan->desc = NULL;
+	chan->busy = false;
+
+	/* Start the next transfer if this driver has a next desc */
+	stm32_mdma_start_transfer(chan);
+}
+
+static irqreturn_t stm32_mdma_irq_handler(int irq, void *devid)
+{
+	struct stm32_mdma_device *dmadev = devid;
+	struct stm32_mdma_chan *chan = devid;
+	u32 reg, id, ien, status, flag;
+
+	/* Find out which channel generates the interrupt */
+	status = readl_relaxed(dmadev->base + STM32_MDMA_GISR0);
+	if (status) {
+		id = __ffs(status);
+	} else {
+		status = readl_relaxed(dmadev->base + STM32_MDMA_GISR1);
+		if (!status) {
+			dev_dbg(mdma2dev(dmadev), "spurious it\n");
+			return IRQ_NONE;
+		}
+		id = __ffs(status);
+		/*
+		 * As GISR0 provides status for channel id from 0 to 31,
+		 * so GISR1 provides status for channel id from 32 to 62
+		 */
+		id += 32;
+	}
+
+	chan = &dmadev->chan[id];
+	if (!chan) {
+		dev_err(chan2dev(chan), "MDMA channel not initialized\n");
+		goto exit;
+	}
+
+	/* Handle interrupt for the channel */
+	spin_lock(&chan->vchan.lock);
+	status = stm32_mdma_read(dmadev, STM32_MDMA_CISR(chan->id));
+	ien = stm32_mdma_read(dmadev, STM32_MDMA_CCR(chan->id));
+	ien &= STM32_MDMA_CCR_IRQ_MASK;
+	ien >>= 1;
+
+	if (!(status & ien)) {
+		spin_unlock(&chan->vchan.lock);
+		dev_dbg(chan2dev(chan),
+			"spurious it (status=0x%04x, ien=0x%04x)\n",
+			status, ien);
+		return IRQ_NONE;
+	}
+
+	flag = __ffs(status & ien);
+	reg = STM32_MDMA_CIFCR(chan->id);
+
+	switch (1 << flag) {
+	case STM32_MDMA_CISR_TEIF:
+		id = chan->id;
+		status = readl_relaxed(dmadev->base + STM32_MDMA_CESR(id));
+		dev_err(chan2dev(chan), "Transfer Err: stat=0x%08x\n", status);
+		stm32_mdma_set_bits(dmadev, reg, STM32_MDMA_CIFCR_CTEIF);
+		break;
+
+	case STM32_MDMA_CISR_CTCIF:
+		stm32_mdma_set_bits(dmadev, reg, STM32_MDMA_CIFCR_CCTCIF);
+		stm32_mdma_xfer_end(chan);
+		break;
+
+	case STM32_MDMA_CISR_BRTIF:
+		stm32_mdma_set_bits(dmadev, reg, STM32_MDMA_CIFCR_CBRTIF);
+		break;
+
+	case STM32_MDMA_CISR_BTIF:
+		stm32_mdma_set_bits(dmadev, reg, STM32_MDMA_CIFCR_CBTIF);
+		chan->curr_hwdesc++;
+		if (chan->desc && chan->desc->cyclic) {
+			if (chan->curr_hwdesc == chan->desc->count)
+				chan->curr_hwdesc = 0;
+			vchan_cyclic_callback(&chan->desc->vdesc);
+		}
+		break;
+
+	case STM32_MDMA_CISR_TCIF:
+		stm32_mdma_set_bits(dmadev, reg, STM32_MDMA_CIFCR_CLTCIF);
+		break;
+
+	default:
+		dev_err(chan2dev(chan), "it %d unhandled (status=0x%04x)\n",
+			1 << flag, status);
+	}
+
+	spin_unlock(&chan->vchan.lock);
+
+exit:
+	return IRQ_HANDLED;
+}
+
+static int stm32_mdma_alloc_chan_resources(struct dma_chan *c)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	int ret;
+
+	chan->desc_pool = dmam_pool_create(dev_name(&c->dev->device),
+					   c->device->dev,
+					   sizeof(struct stm32_mdma_hwdesc),
+					  __alignof__(struct stm32_mdma_hwdesc),
+					   0);
+	if (!chan->desc_pool) {
+		dev_err(chan2dev(chan), "failed to allocate descriptor pool\n");
+		return -ENOMEM;
+	}
+
+	ret = clk_prepare_enable(dmadev->clk);
+	if (ret < 0) {
+		dev_err(chan2dev(chan), "clk_prepare_enable failed: %d\n", ret);
+		return ret;
+	}
+
+	ret = stm32_mdma_disable_chan(chan);
+	if (ret < 0)
+		clk_disable_unprepare(dmadev->clk);
+
+	return ret;
+}
+
+static void stm32_mdma_free_chan_resources(struct dma_chan *c)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	unsigned long flags;
+
+	dev_dbg(chan2dev(chan), "Freeing channel %d\n", chan->id);
+
+	if (chan->busy) {
+		spin_lock_irqsave(&chan->vchan.lock, flags);
+		stm32_mdma_stop(chan);
+		chan->desc = NULL;
+		spin_unlock_irqrestore(&chan->vchan.lock, flags);
+	}
+
+	clk_disable_unprepare(dmadev->clk);
+	vchan_free_chan_resources(to_virt_chan(c));
+	dmam_pool_destroy(chan->desc_pool);
+	chan->desc_pool = NULL;
+}
+
+static struct dma_chan *stm32_mdma_of_xlate(struct of_phandle_args *dma_spec,
+					    struct of_dma *ofdma)
+{
+	struct stm32_mdma_device *dmadev = ofdma->of_dma_data;
+	struct stm32_mdma_chan *chan;
+	struct dma_chan *c;
+	struct stm32_mdma_chan_config config;
+
+	if (dma_spec->args_count < 5) {
+		dev_err(mdma2dev(dmadev), "Bad number of args\n");
+		return NULL;
+	}
+
+	config.request = dma_spec->args[0];
+	config.priority_level = dma_spec->args[1];
+	config.transfer_config = dma_spec->args[2];
+	config.mask_addr = dma_spec->args[3];
+	config.mask_data = dma_spec->args[4];
+
+	if (config.request >= dmadev->nr_requests) {
+		dev_err(mdma2dev(dmadev), "Bad request line\n");
+		return NULL;
+	}
+
+	if (config.priority_level > STM32_MDMA_VERY_HIGH_PRIORITY) {
+		dev_err(mdma2dev(dmadev), "Priority level not supported\n");
+		return NULL;
+	}
+
+	c = dma_get_any_slave_channel(&dmadev->ddev);
+	if (!c) {
+		dev_err(mdma2dev(dmadev), "No more channel avalaible\n");
+		return NULL;
+	}
+
+	chan = to_stm32_mdma_chan(c);
+	chan->chan_config = config;
+
+	return c;
+}
+
+static const struct of_device_id stm32_mdma_of_match[] = {
+	{ .compatible = "st,stm32h7-mdma", },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, stm32_mdma_of_match);
+
+static int stm32_mdma_probe(struct platform_device *pdev)
+{
+	struct stm32_mdma_chan *chan;
+	struct stm32_mdma_device *dmadev;
+	struct dma_device *dd;
+	struct device_node *of_node;
+	struct resource *res;
+	u32 nr_channels, nr_requests;
+	int i, count, ret;
+
+	of_node = pdev->dev.of_node;
+	if (!of_node)
+		return -ENODEV;
+
+	ret = device_property_read_u32(&pdev->dev, "dma-channels",
+				       &nr_channels);
+	if (ret) {
+		nr_channels = STM32_MDMA_MAX_CHANNELS;
+		dev_warn(&pdev->dev, "MDMA defaulting on %i channels\n",
+			 nr_channels);
+	}
+
+	ret = device_property_read_u32(&pdev->dev, "dma-requests",
+				       &nr_requests);
+	if (ret) {
+		nr_requests = STM32_MDMA_MAX_REQUESTS;
+		dev_warn(&pdev->dev, "MDMA defaulting on %i request lines\n",
+			 nr_requests);
+	}
+
+	count = of_property_count_u32_elems(of_node, "st,ahb-addr-masks");
+	if (count < 0)
+		count = 0;
+
+	dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev) + sizeof(u32) * count,
+			      GFP_KERNEL);
+	if (!dmadev)
+		return -ENOMEM;
+
+	dmadev->nr_channels = nr_channels;
+	dmadev->nr_requests = nr_requests;
+	of_property_read_u32_array(of_node, "st,ahb-addr-masks",
+				   dmadev->ahb_addr_masks,
+				   count);
+	dmadev->nr_ahb_addr_masks = count;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	dmadev->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(dmadev->base))
+		return PTR_ERR(dmadev->base);
+
+	dmadev->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(dmadev->clk)) {
+		dev_err(&pdev->dev, "Error: Missing controller clock\n");
+		return PTR_ERR(dmadev->clk);
+	}
+
+	dmadev->rst = devm_reset_control_get(&pdev->dev, NULL);
+	if (!IS_ERR(dmadev->rst)) {
+		reset_control_assert(dmadev->rst);
+		udelay(2);
+		reset_control_deassert(dmadev->rst);
+	}
+
+	dd = &dmadev->ddev;
+	dma_cap_set(DMA_SLAVE, dd->cap_mask);
+	dma_cap_set(DMA_PRIVATE, dd->cap_mask);
+	dma_cap_set(DMA_CYCLIC, dd->cap_mask);
+	dma_cap_set(DMA_MEMCPY, dd->cap_mask);
+	dd->device_alloc_chan_resources = stm32_mdma_alloc_chan_resources;
+	dd->device_free_chan_resources = stm32_mdma_free_chan_resources;
+	dd->device_tx_status = stm32_mdma_tx_status;
+	dd->device_issue_pending = stm32_mdma_issue_pending;
+	dd->device_prep_slave_sg = stm32_mdma_prep_slave_sg;
+	dd->device_prep_dma_cyclic = stm32_mdma_prep_dma_cyclic;
+	dd->device_prep_dma_memcpy = stm32_mdma_prep_dma_memcpy;
+	dd->device_config = stm32_mdma_slave_config;
+	dd->device_pause = stm32_mdma_pause;
+	dd->device_resume = stm32_mdma_resume;
+	dd->device_terminate_all = stm32_mdma_terminate_all;
+	dd->device_synchronize = stm32_mdma_synchronize;
+	dd->src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
+		BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
+		BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) |
+		BIT(DMA_SLAVE_BUSWIDTH_8_BYTES);
+	dd->dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
+		BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
+		BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) |
+		BIT(DMA_SLAVE_BUSWIDTH_8_BYTES);
+	dd->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV) |
+		BIT(DMA_MEM_TO_MEM);
+	dd->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
+	dd->max_burst = STM32_MDMA_MAX_BURST;
+	dd->dev = &pdev->dev;
+	INIT_LIST_HEAD(&dd->channels);
+
+	for (i = 0; i < dmadev->nr_channels; i++) {
+		chan = &dmadev->chan[i];
+		chan->id = i;
+		chan->vchan.desc_free = stm32_mdma_desc_free;
+		vchan_init(&chan->vchan, dd);
+	}
+
+	dmadev->irq = platform_get_irq(pdev, 0);
+	if (dmadev->irq < 0) {
+		dev_err(&pdev->dev, "failed to get IRQ\n");
+		return dmadev->irq;
+	}
+
+	ret = devm_request_irq(&pdev->dev, dmadev->irq, stm32_mdma_irq_handler,
+			       0, dev_name(&pdev->dev), dmadev);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to request IRQ\n");
+		return ret;
+	}
+
+	ret = dma_async_device_register(dd);
+	if (ret)
+		return ret;
+
+	ret = of_dma_controller_register(of_node, stm32_mdma_of_xlate, dmadev);
+	if (ret < 0) {
+		dev_err(&pdev->dev,
+			"STM32 MDMA DMA OF registration failed %d\n", ret);
+		goto err_unregister;
+	}
+
+	platform_set_drvdata(pdev, dmadev);
+
+	dev_info(&pdev->dev, "STM32 MDMA driver registered\n");
+
+	return 0;
+
+err_unregister:
+	dma_async_device_unregister(dd);
+
+	return ret;
+}
+
+static struct platform_driver stm32_mdma_driver = {
+	.driver = {
+		.name = "stm32-mdma",
+		.of_match_table = stm32_mdma_of_match,
+	},
+};
+
+static int __init stm32_mdma_init(void)
+{
+	return platform_driver_probe(&stm32_mdma_driver, stm32_mdma_probe);
+}
+
+subsys_initcall(stm32_mdma_init);
+
+MODULE_DESCRIPTION("Driver for STM32 MDMA controller");
+MODULE_AUTHOR("M'boumba Cedric Madianga <cedric.madianga@gmail.com>");
+MODULE_AUTHOR("Pierre-Yves Mordret <pierre-yves.mordret@st.com>");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 26+ messages in thread

* [PATCH v3 2/4] dmaengine: Add STM32 MDMA driver
@ 2017-07-26  9:48   ` Pierre-Yves MORDRET
  0 siblings, 0 replies; 26+ messages in thread
From: Pierre-Yves MORDRET @ 2017-07-26  9:48 UTC (permalink / raw)
  To: linux-arm-kernel

This patch adds the driver for the STM32 MDMA controller.

Master Direct memory access (MDMA) is used in order to provide high-speed
data transfer between memory and memory or between peripherals and memory.

MDMA controller provides a master AXI interface for main memory and
peripheral registers access (system access port) and a master AHB
interface only for Cortex-M7 TCM memory access (TCM access port).

MDMA works in conjunction with the standard DMA controllers (DMA1 or DMA2).
It offers up to 64 channels, each dedicated to managing memory access
requests from one of the DMA stream memory buffer or other peripherals
(w/ integrated FIFO).

Signed-off-by: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
---
  Version history:
     v3:
         * Update header template
         * Unsigned expression compared with zero
         * Rework stm32_mdma_get_max_width
         * moved to src/dst case where they are used in set_xfer
         * Change of_property_* with device_property_*
         * Add dev_warn whether default value is used
         * Indentation
         * Add MODULE_*
     v2:
         * change compatible into st,stm32h7-mdma to be more SoC specific
         * optimize some functions
         * functions factorization
         * remove useless code
---
---
 drivers/dma/Kconfig      |   12 +
 drivers/dma/Makefile     |    1 +
 drivers/dma/stm32-mdma.c | 1565 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 1578 insertions(+)
 create mode 100644 drivers/dma/stm32-mdma.c

diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index fadc4d8..36cac16 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -483,6 +483,18 @@ config STM32_DMA
 	  If you have a board based on such a MCU and wish to use DMA say Y
 	  here.
 
+config STM32_MDMA
+	bool "STMicroelectronics STM32 master dma support"
+	depends on ARCH_STM32 || COMPILE_TEST
+	select DMA_ENGINE
+	select DMA_OF
+	select DMA_VIRTUAL_CHANNELS
+	help
+	  Enable support for the on-chip MDMA controller on STMicroelectronics
+	  STM32 platforms.
+	  If you have a board based on STM32 SoC and wish to use the master DMA
+	  say Y here.
+
 config S3C24XX_DMAC
 	bool "Samsung S3C24XX DMA support"
 	depends on ARCH_S3C24XX || COMPILE_TEST
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index f08f8de..b9747ba 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -59,6 +59,7 @@ obj-$(CONFIG_RENESAS_DMA) += sh/
 obj-$(CONFIG_SIRF_DMA) += sirf-dma.o
 obj-$(CONFIG_STE_DMA40) += ste_dma40.o ste_dma40_ll.o
 obj-$(CONFIG_STM32_DMA) += stm32-dma.o
+obj-$(CONFIG_STM32_MDMA) += stm32-mdma.o
 obj-$(CONFIG_S3C24XX_DMAC) += s3c24xx-dma.o
 obj-$(CONFIG_TXX9_DMAC) += txx9dmac.o
 obj-$(CONFIG_TEGRA20_APB_DMA) += tegra20-apb-dma.o
diff --git a/drivers/dma/stm32-mdma.c b/drivers/dma/stm32-mdma.c
new file mode 100644
index 0000000..a5b351b
--- /dev/null
+++ b/drivers/dma/stm32-mdma.c
@@ -0,0 +1,1565 @@
+/*
+ *
+ * Copyright (C) STMicroelectronics SA 2017
+ * Author(s): M'boumba Cedric Madianga <cedric.madianga@gmail.com>
+ *            Pierre-Yves Mordret <pierre-yves.mordret@st.com>
+ *
+ * License terms: GPL V2.0.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+ * details.
+ *
+ * Driver for STM32 MDMA controller
+ *
+ * Inspired by stm32-dma.c and dma-jz4780.c
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmapool.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/iopoll.h>
+#include <linux/jiffies.h>
+#include <linux/list.h>
+#include <linux/log2.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_dma.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+
+#include "virt-dma.h"
+
+#define STM32_MDMA_GISR0		0x0000 /* MDMA Int Status Reg 1 */
+#define STM32_MDMA_GISR1		0x0004 /* MDMA Int Status Reg 2 */
+
+/* MDMA Channel x interrupt/status register */
+#define STM32_MDMA_CISR(x)		(0x40 + 0x40 * (x)) /* x = 0..62 */
+#define STM32_MDMA_CISR_CRQA		BIT(16)
+#define STM32_MDMA_CISR_TCIF		BIT(4)
+#define STM32_MDMA_CISR_BTIF		BIT(3)
+#define STM32_MDMA_CISR_BRTIF		BIT(2)
+#define STM32_MDMA_CISR_CTCIF		BIT(1)
+#define STM32_MDMA_CISR_TEIF		BIT(0)
+
+/* MDMA Channel x interrupt flag clear register */
+#define STM32_MDMA_CIFCR(x)		(0x44 + 0x40 * (x))
+#define STM32_MDMA_CIFCR_CLTCIF		BIT(4)
+#define STM32_MDMA_CIFCR_CBTIF		BIT(3)
+#define STM32_MDMA_CIFCR_CBRTIF		BIT(2)
+#define STM32_MDMA_CIFCR_CCTCIF		BIT(1)
+#define STM32_MDMA_CIFCR_CTEIF		BIT(0)
+#define STM32_MDMA_CIFCR_CLEAR_ALL	(STM32_MDMA_CIFCR_CLTCIF \
+					| STM32_MDMA_CIFCR_CBTIF \
+					| STM32_MDMA_CIFCR_CBRTIF \
+					| STM32_MDMA_CIFCR_CCTCIF \
+					| STM32_MDMA_CIFCR_CTEIF)
+
+/* MDMA Channel x error status register */
+#define STM32_MDMA_CESR(x)		(0x48 + 0x40 * (x))
+#define STM32_MDMA_CESR_BSE		BIT(11)
+#define STM32_MDMA_CESR_ASR		BIT(10)
+#define STM32_MDMA_CESR_TEMD		BIT(9)
+#define STM32_MDMA_CESR_TELD		BIT(8)
+#define STM32_MDMA_CESR_TED		BIT(7)
+#define STM32_MDMA_CESR_TEA_MASK	GENMASK(6, 0)
+
+/* MDMA Channel x control register */
+#define STM32_MDMA_CCR(x)		(0x4C + 0x40 * (x))
+#define STM32_MDMA_CCR_SWRQ		BIT(16)
+#define STM32_MDMA_CCR_WEX		BIT(14)
+#define STM32_MDMA_CCR_HEX		BIT(13)
+#define STM32_MDMA_CCR_BEX		BIT(12)
+#define STM32_MDMA_CCR_PL_MASK		GENMASK(7, 6)
+#define STM32_MDMA_CCR_PL(n)		(((n) & 0x3) << 6)
+#define STM32_MDMA_CCR_TCIE		BIT(5)
+#define STM32_MDMA_CCR_BTIE		BIT(4)
+#define STM32_MDMA_CCR_BRTIE		BIT(3)
+#define STM32_MDMA_CCR_CTCIE		BIT(2)
+#define STM32_MDMA_CCR_TEIE		BIT(1)
+#define STM32_MDMA_CCR_EN		BIT(0)
+#define STM32_MDMA_CCR_IRQ_MASK		(STM32_MDMA_CCR_TCIE \
+					| STM32_MDMA_CCR_BTIE \
+					| STM32_MDMA_CCR_BRTIE \
+					| STM32_MDMA_CCR_CTCIE \
+					| STM32_MDMA_CCR_TEIE)
+
+/* MDMA Channel x transfer configuration register */
+#define STM32_MDMA_CTCR(x)		(0x50 + 0x40 * (x))
+#define STM32_MDMA_CTCR_BWM		BIT(31)
+#define STM32_MDMA_CTCR_SWRM		BIT(30)
+#define STM32_MDMA_CTCR_TRGM_MSK	GENMASK(29, 28)
+#define STM32_MDMA_CTCR_TRGM(n)		(((n) & 0x3) << 28)
+#define STM32_MDMA_CTCR_TRGM_GET(n)	(((n) & STM32_MDMA_CTCR_TRGM_MSK) >> 28)
+#define STM32_MDMA_CTCR_PAM_MASK	GENMASK(27, 26)
+#define STM32_MDMA_CTCR_PAM(n)		(((n) & 0x3) << 26)
+#define STM32_MDMA_CTCR_PKE		BIT(25)
+#define STM32_MDMA_CTCR_TLEN_MSK	GENMASK(24, 18)
+#define STM32_MDMA_CTCR_TLEN(n)		(((n) & 0x7f) << 18)
+#define STM32_MDMA_CTCR_TLEN_GET(n)	(((n) & STM32_MDMA_CTCR_TLEN_MSK) >> 18)
+#define STM32_MDMA_CTCR_LEN2_MSK	GENMASK(25, 18)
+#define STM32_MDMA_CTCR_LEN2(n)	(((n) & 0xff) << 18)
+#define STM32_MDMA_CTCR_LEN2_GET(n)	(((n) & STM32_MDMA_CTCR_LEN2_MSK) >> 18)
+#define STM32_MDMA_CTCR_DBURST_MASK	GENMASK(17, 15)
+#define STM32_MDMA_CTCR_DBURST(n)	(((n) & 0x7) << 15)
+#define STM32_MDMA_CTCR_SBURST_MASK	GENMASK(14, 12)
+#define STM32_MDMA_CTCR_SBURST(n)	(((n) & 0x7) << 12)
+#define STM32_MDMA_CTCR_DINCOS_MASK	GENMASK(11, 10)
+#define STM32_MDMA_CTCR_DINCOS(n)	(((n) & 0x3) << 10)
+#define STM32_MDMA_CTCR_SINCOS_MASK	GENMASK(9, 8)
+#define STM32_MDMA_CTCR_SINCOS(n)	(((n) & 0x3) << 8)
+#define STM32_MDMA_CTCR_DSIZE_MASK	GENMASK(7, 6)
+#define STM32_MDMA_CTCR_DSIZE(n)	(((n) & 0x3) << 6)
+#define STM32_MDMA_CTCR_SSIZE_MASK	GENMASK(5, 4)
+#define STM32_MDMA_CTCR_SSIZE(n)	(((n) & 0x3) << 4)
+#define STM32_MDMA_CTCR_DINC_MASK	GENMASK(3, 2)
+#define STM32_MDMA_CTCR_DINC(n)		(((n) & 0x3) << 2)
+#define STM32_MDMA_CTCR_SINC_MASK	GENMASK(1, 0)
+#define STM32_MDMA_CTCR_SINC(n)		((n) & STM32_MDMA_CTCR_SINC_MASK)
+#define STM32_MDMA_CTCR_CFG_MASK	(STM32_MDMA_CTCR_SINC_MASK \
+					| STM32_MDMA_CTCR_DINC_MASK \
+					| STM32_MDMA_CTCR_SINCOS_MASK \
+					| STM32_MDMA_CTCR_DINCOS_MASK \
+					| STM32_MDMA_CTCR_LEN2_MSK \
+					| STM32_MDMA_CTCR_TRGM_MSK)
+
+/* MDMA Channel x block number of data register */
+#define STM32_MDMA_CBNDTR(x)		(0x54 + 0x40 * (x))
+#define STM32_MDMA_CBNDTR_BRC_MK	GENMASK(31, 20)
+#define STM32_MDMA_CBNDTR_BRC(n)	(((n) & 0xfff) << 20)
+#define STM32_MDMA_CBNDTR_BRC_GET(n)	(((n) & STM32_MDMA_CBNDTR_BRC_MK) >> 20)
+#define STM32_MDMA_CBNDTR_BRDUM		BIT(19)
+#define STM32_MDMA_CBNDTR_BRSUM		BIT(18)
+#define STM32_MDMA_CBNDTR_BNDT_MASK	GENMASK(16, 0)
+#define STM32_MDMA_CBNDTR_BNDT(n)	((n) & STM32_MDMA_CBNDTR_BNDT_MASK)
+
+/* MDMA Channel x source address register */
+#define STM32_MDMA_CSAR(x)		(0x58 + 0x40 * (x))
+
+/* MDMA Channel x destination address register */
+#define STM32_MDMA_CDAR(x)		(0x5C + 0x40 * (x))
+
+/* MDMA Channel x block repeat address update register */
+#define STM32_MDMA_CBRUR(x)		(0x60 + 0x40 * (x))
+#define STM32_MDMA_CBRUR_DUV_MASK	GENMASK(31, 16)
+#define STM32_MDMA_CBRUR_DUV(n)		(((n) & 0xffff) << 16)
+#define STM32_MDMA_CBRUR_SUV_MASK	GENMASK(15, 0)
+#define STM32_MDMA_CBRUR_SUV(n)		((n) & STM32_MDMA_CBRUR_SUV_MASK)
+
+/* MDMA Channel x link address register */
+#define STM32_MDMA_CLAR(x)		(0x64 + 0x40 * (x))
+
+/* MDMA Channel x trigger and bus selection register */
+#define STM32_MDMA_CTBR(x)		(0x68 + 0x40 * (x))
+#define STM32_MDMA_CTBR_DBUS		BIT(17)
+#define STM32_MDMA_CTBR_SBUS		BIT(16)
+#define STM32_MDMA_CTBR_TSEL_MASK	GENMASK(7, 0)
+#define STM32_MDMA_CTBR_TSEL(n)	((n) & STM32_MDMA_CTBR_TSEL_MASK)
+
+/* MDMA Channel x mask address register */
+#define STM32_MDMA_CMAR(x)		(0x70 + 0x40 * (x))
+
+/* MDMA Channel x mask data register */
+#define STM32_MDMA_CMDR(x)		(0x74 + 0x40 * (x))
+
+#define STM32_MDMA_MAX_BUF_LEN		128
+#define STM32_MDMA_MAX_BLOCK_LEN	65536
+#define STM32_MDMA_MAX_CHANNELS		63
+#define STM32_MDMA_MAX_REQUESTS		256
+#define STM32_MDMA_MAX_BURST		128
+#define STM32_MDMA_VERY_HIGH_PRIORITY	0x11
+
+enum stm32_mdma_trigger_mode {
+	STM32_MDMA_BUFFER,
+	STM32_MDMA_BLOCK,
+	STM32_MDMA_BLOCK_REP,
+	STM32_MDMA_LINKED_LIST,
+};
+
+enum stm32_mdma_width {
+	STM32_MDMA_BYTE,
+	STM32_MDMA_HALF_WORD,
+	STM32_MDMA_WORD,
+	STM32_MDMA_DOUBLE_WORD,
+};
+
+enum stm32_mdma_inc_mode {
+	STM32_MDMA_FIXED = 0,
+	STM32_MDMA_INC = 2,
+	STM32_MDMA_DEC = 3,
+};
+
+struct stm32_mdma_chan_config {
+	u32 request;
+	u32 priority_level;
+	u32 transfer_config;
+	u32 mask_addr;
+	u32 mask_data;
+};
+
+struct stm32_mdma_hwdesc {
+	u32 ctcr;
+	u32 cbndtr;
+	u32 csar;
+	u32 cdar;
+	u32 cbrur;
+	u32 clar;
+	u32 ctbr;
+	u32 dummy;
+	u32 cmar;
+	u32 cmdr;
+} __aligned(64);
+
+struct stm32_mdma_desc {
+	struct virt_dma_desc vdesc;
+	u32 ccr;
+	struct stm32_mdma_hwdesc *hwdesc;
+	dma_addr_t hwdesc_phys;
+	bool cyclic;
+	u32 count;
+};
+
+struct stm32_mdma_chan {
+	struct virt_dma_chan vchan;
+	struct dma_pool *desc_pool;
+	u32 id;
+	struct stm32_mdma_desc *desc;
+	u32 curr_hwdesc;
+	struct dma_slave_config dma_config;
+	struct stm32_mdma_chan_config chan_config;
+	bool busy;
+	u32 mem_burst;
+	u32 mem_width;
+};
+
+struct stm32_mdma_device {
+	struct dma_device ddev;
+	void __iomem *base;
+	struct clk *clk;
+	int irq;
+	struct reset_control *rst;
+	u32 nr_channels;
+	u32 nr_requests;
+	u32 nr_ahb_addr_masks;
+	struct stm32_mdma_chan chan[STM32_MDMA_MAX_CHANNELS];
+	u32 ahb_addr_masks[];
+};
+
+static struct stm32_mdma_device *stm32_mdma_get_dev(
+	struct stm32_mdma_chan *chan)
+{
+	return container_of(chan->vchan.chan.device, struct stm32_mdma_device,
+			    ddev);
+}
+
+static struct stm32_mdma_chan *to_stm32_mdma_chan(struct dma_chan *c)
+{
+	return container_of(c, struct stm32_mdma_chan, vchan.chan);
+}
+
+static struct stm32_mdma_desc *to_stm32_mdma_desc(struct virt_dma_desc *vdesc)
+{
+	return container_of(vdesc, struct stm32_mdma_desc, vdesc);
+}
+
+static struct device *chan2dev(struct stm32_mdma_chan *chan)
+{
+	return &chan->vchan.chan.dev->device;
+}
+
+static struct device *mdma2dev(struct stm32_mdma_device *mdma_dev)
+{
+	return mdma_dev->ddev.dev;
+}
+
+static u32 stm32_mdma_read(struct stm32_mdma_device *dmadev, u32 reg)
+{
+	return readl_relaxed(dmadev->base + reg);
+}
+
+static void stm32_mdma_write(struct stm32_mdma_device *dmadev, u32 reg, u32 val)
+{
+	writel_relaxed(val, dmadev->base + reg);
+}
+
+static void stm32_mdma_set_bits(struct stm32_mdma_device *dmadev, u32 reg,
+				u32 mask)
+{
+	void __iomem *addr = dmadev->base + reg;
+
+	writel_relaxed(readl_relaxed(addr) | mask, addr);
+}
+
+static void stm32_mdma_clr_bits(struct stm32_mdma_device *dmadev, u32 reg,
+				u32 mask)
+{
+	void __iomem *addr = dmadev->base + reg;
+
+	writel_relaxed(readl_relaxed(addr) & ~mask, addr);
+}
+
+static struct stm32_mdma_desc *stm32_mdma_alloc_desc(
+		struct stm32_mdma_chan *chan, u32 count)
+{
+	struct stm32_mdma_desc *desc;
+
+	desc = kzalloc(sizeof(*desc), GFP_NOWAIT);
+	if (!desc)
+		return NULL;
+
+	desc->hwdesc = dma_pool_alloc(chan->desc_pool, GFP_NOWAIT,
+				      &desc->hwdesc_phys);
+	if (!desc->hwdesc) {
+		dev_err(chan2dev(chan), "Failed to allocate descriptor\n");
+		kfree(desc);
+		return NULL;
+	}
+
+	desc->count = count;
+
+	return desc;
+}
+
+static void stm32_mdma_desc_free(struct virt_dma_desc *vdesc)
+{
+	struct stm32_mdma_desc *desc = to_stm32_mdma_desc(vdesc);
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(vdesc->tx.chan);
+
+	dma_pool_free(chan->desc_pool, desc->hwdesc, desc->hwdesc_phys);
+	kfree(desc);
+}
+
+static int stm32_mdma_get_width(struct stm32_mdma_chan *chan,
+				enum dma_slave_buswidth width)
+{
+	switch (width) {
+	case DMA_SLAVE_BUSWIDTH_1_BYTE:
+	case DMA_SLAVE_BUSWIDTH_2_BYTES:
+	case DMA_SLAVE_BUSWIDTH_4_BYTES:
+	case DMA_SLAVE_BUSWIDTH_8_BYTES:
+		return ffs(width) - 1;
+	default:
+		dev_err(chan2dev(chan), "Dma bus width not supported\n");
+		return -EINVAL;
+	}
+}
+
+static enum dma_slave_buswidth stm32_mdma_get_max_width(u32 buf_len, u32 tlen)
+{
+	enum dma_slave_buswidth max_width = DMA_SLAVE_BUSWIDTH_8_BYTES;
+
+	for (max_width = DMA_SLAVE_BUSWIDTH_8_BYTES;
+	     max_width > DMA_SLAVE_BUSWIDTH_1_BYTE;
+	     max_width >>= 1) {
+		if (((buf_len % max_width) == 0) && (tlen >= max_width))
+			break;
+	}
+
+	return max_width;
+}
+
+static u32 stm32_mdma_get_best_burst(u32 buf_len, u32 tlen, u32 max_burst,
+				     enum dma_slave_buswidth width)
+{
+	u32 best_burst = max_burst;
+	u32 burst_len = best_burst * width;
+
+	while ((burst_len > 0) && (tlen % burst_len)) {
+		best_burst = best_burst >> 1;
+		burst_len = best_burst * width;
+	}
+
+	return (best_burst > 0) ? best_burst : 1;
+}
+
+static int stm32_mdma_disable_chan(struct stm32_mdma_chan *chan)
+{
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	u32 ccr, cisr, id, reg;
+	int ret;
+
+	id = chan->id;
+	reg = STM32_MDMA_CCR(id);
+
+	/* Disable interrupts */
+	stm32_mdma_clr_bits(dmadev, reg, STM32_MDMA_CCR_IRQ_MASK);
+
+	ccr = stm32_mdma_read(dmadev, reg);
+	if (ccr & STM32_MDMA_CCR_EN) {
+		stm32_mdma_clr_bits(dmadev, reg, STM32_MDMA_CCR_EN);
+
+		/* Ensure that any ongoing transfer has been completed */
+		ret = readl_relaxed_poll_timeout_atomic(
+				dmadev->base + STM32_MDMA_CISR(id), cisr,
+				(cisr & STM32_MDMA_CISR_CTCIF), 10, 1000);
+		if (ret) {
+			dev_err(chan2dev(chan), "%s: timeout!\n", __func__);
+			return -EBUSY;
+		}
+	}
+
+	return 0;
+}
+
+static void stm32_mdma_stop(struct stm32_mdma_chan *chan)
+{
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	u32 status;
+	int ret;
+
+	/* Disable DMA */
+	ret = stm32_mdma_disable_chan(chan);
+	if (ret < 0)
+		return;
+
+	/* Clear interrupt status if it is there */
+	status = stm32_mdma_read(dmadev, STM32_MDMA_CISR(chan->id));
+	if (status) {
+		dev_dbg(chan2dev(chan), "%s(): clearing interrupt: 0x%08x\n",
+			__func__, status);
+		stm32_mdma_set_bits(dmadev, STM32_MDMA_CIFCR(chan->id), status);
+	}
+
+	chan->busy = false;
+}
+
+static void stm32_mdma_set_bus(struct stm32_mdma_device *dmadev, u32 *ctbr,
+			       u32 ctbr_mask, u32 src_addr)
+{
+	u32 mask;
+	int i;
+
+	/* Check if memory device is on AHB or AXI */
+	*ctbr &= ~ctbr_mask;
+	mask = src_addr & 0xF0000000;
+	for (i = 0; i < dmadev->nr_ahb_addr_masks; i++) {
+		if (mask == dmadev->ahb_addr_masks[i]) {
+			*ctbr |= ctbr_mask;
+			break;
+		}
+	}
+}
+
+static int stm32_mdma_set_xfer_param(struct stm32_mdma_chan *chan,
+				     enum dma_transfer_direction direction,
+				     u32 *mdma_ccr, u32 *mdma_ctcr,
+				     u32 *mdma_ctbr, u32 buf_len)
+{
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	struct stm32_mdma_chan_config *chan_config = &chan->chan_config;
+	enum dma_slave_buswidth src_addr_width, dst_addr_width;
+	phys_addr_t src_addr, dst_addr;
+	int src_bus_width, dst_bus_width;
+	u32 src_maxburst, dst_maxburst, src_best_burst, dst_best_burst;
+	u32 ccr, ctcr, ctbr, tlen;
+
+	src_addr_width = chan->dma_config.src_addr_width;
+	dst_addr_width = chan->dma_config.dst_addr_width;
+	src_maxburst = chan->dma_config.src_maxburst;
+	dst_maxburst = chan->dma_config.dst_maxburst;
+
+	ccr = stm32_mdma_read(dmadev, STM32_MDMA_CCR(chan->id));
+	ctcr = stm32_mdma_read(dmadev, STM32_MDMA_CTCR(chan->id));
+	ctbr = stm32_mdma_read(dmadev, STM32_MDMA_CTBR(chan->id));
+
+	/* Enable HW request mode */
+	ctcr &= ~STM32_MDMA_CTCR_SWRM;
+
+	/* Set DINC, SINC, DINCOS, SINCOS, TRGM and TLEN retrieve from DT */
+	ctcr &= ~STM32_MDMA_CTCR_CFG_MASK;
+	ctcr |= chan_config->transfer_config & STM32_MDMA_CTCR_CFG_MASK;
+
+	/*
+	 * For buffer transfer length (TLEN) we have to set
+	 * the number of bytes - 1 in CTCR register
+	 */
+	tlen = STM32_MDMA_CTCR_LEN2_GET(ctcr);
+	ctcr &= ~STM32_MDMA_CTCR_LEN2_MSK;
+	ctcr |= STM32_MDMA_CTCR_TLEN((tlen - 1));
+
+	/* Check burst size constraints */
+	if (src_maxburst * src_addr_width > STM32_MDMA_MAX_BURST ||
+	    dst_maxburst * dst_addr_width > STM32_MDMA_MAX_BURST) {
+		dev_err(chan2dev(chan),
+			"burst size * bus width higher than %d bytes\n",
+			STM32_MDMA_MAX_BURST);
+		return -EINVAL;
+	}
+
+	if ((!is_power_of_2(src_maxburst) && src_maxburst > 0) ||
+	    (!is_power_of_2(dst_maxburst) && dst_maxburst > 0)) {
+		dev_err(chan2dev(chan), "burst size must be a power of 2\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * Configure channel control:
+	 * - Clear SW request as in this case this is a HW one
+	 * - Clear WEX, HEX and BEX bits
+	 * - Set priority level
+	 */
+	ccr &= ~(STM32_MDMA_CCR_SWRQ | STM32_MDMA_CCR_WEX | STM32_MDMA_CCR_HEX |
+		 STM32_MDMA_CCR_BEX | STM32_MDMA_CCR_PL_MASK);
+	ccr |= STM32_MDMA_CCR_PL(chan_config->priority_level);
+
+	/* Configure Trigger selection */
+	ctbr &= ~STM32_MDMA_CTBR_TSEL_MASK;
+	ctbr |= STM32_MDMA_CTBR_TSEL(chan_config->request);
+
+	switch (direction) {
+	case DMA_MEM_TO_DEV:
+		/* Set device data size */
+		dst_bus_width = stm32_mdma_get_width(chan, dst_addr_width);
+		if (dst_bus_width < 0)
+			return dst_bus_width;
+		ctcr &= ~STM32_MDMA_CTCR_DSIZE_MASK;
+		ctcr |= STM32_MDMA_CTCR_DSIZE(dst_bus_width);
+
+		/* Set device burst value */
+		dst_best_burst = stm32_mdma_get_best_burst(buf_len, tlen,
+							   dst_maxburst,
+							   dst_addr_width);
+		chan->mem_burst = dst_best_burst;
+		ctcr &= ~STM32_MDMA_CTCR_DBURST_MASK;
+		ctcr |= STM32_MDMA_CTCR_DBURST((ilog2(dst_best_burst)));
+
+		/* Set memory data size */
+		src_addr_width = stm32_mdma_get_max_width(buf_len, tlen);
+		chan->mem_width = src_addr_width;
+		src_bus_width = stm32_mdma_get_width(chan, src_addr_width);
+		if (src_bus_width < 0)
+			return src_bus_width;
+		ctcr &= ~STM32_MDMA_CTCR_SSIZE_MASK |
+			STM32_MDMA_CTCR_SINCOS_MASK;
+		ctcr |= STM32_MDMA_CTCR_SSIZE(src_bus_width) |
+			STM32_MDMA_CTCR_SINCOS(src_bus_width);
+
+		/* Set memory burst value */
+		src_maxburst = STM32_MDMA_MAX_BUF_LEN / src_addr_width;
+		src_best_burst = stm32_mdma_get_best_burst(buf_len, tlen,
+							   src_maxburst,
+							   src_addr_width);
+		chan->mem_burst = src_best_burst;
+		ctcr &= ~STM32_MDMA_CTCR_SBURST_MASK;
+		ctcr |= STM32_MDMA_CTCR_SBURST((ilog2(src_best_burst)));
+
+		/* Select bus */
+		dst_addr = chan->dma_config.dst_addr;
+		stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_DBUS,
+				   dst_addr);
+
+		/* Set destination address */
+		stm32_mdma_write(dmadev, STM32_MDMA_CDAR(chan->id), dst_addr);
+		break;
+
+	case DMA_DEV_TO_MEM:
+		/* Set device data size */
+		src_bus_width = stm32_mdma_get_width(chan, src_addr_width);
+		if (src_bus_width < 0)
+			return src_bus_width;
+		ctcr &= ~STM32_MDMA_CTCR_SSIZE_MASK;
+		ctcr |= STM32_MDMA_CTCR_SSIZE(src_bus_width);
+
+		/* Set device burst value */
+		src_best_burst = stm32_mdma_get_best_burst(buf_len, tlen,
+							   src_maxburst,
+							   src_addr_width);
+		ctcr &= ~STM32_MDMA_CTCR_SBURST_MASK;
+		ctcr |= STM32_MDMA_CTCR_SBURST((ilog2(src_best_burst)));
+
+		/* Set memory data size */
+		dst_addr_width = stm32_mdma_get_max_width(buf_len, tlen);
+		chan->mem_width = dst_addr_width;
+		dst_bus_width = stm32_mdma_get_width(chan, dst_addr_width);
+		if (dst_bus_width < 0)
+			return dst_bus_width;
+		ctcr &= ~(STM32_MDMA_CTCR_DSIZE_MASK |
+			STM32_MDMA_CTCR_DINCOS_MASK);
+		ctcr |= STM32_MDMA_CTCR_DSIZE(dst_bus_width) |
+			STM32_MDMA_CTCR_DINCOS(dst_bus_width);
+
+		/* Set memory burst value */
+		dst_maxburst = STM32_MDMA_MAX_BUF_LEN / dst_addr_width;
+		dst_best_burst = stm32_mdma_get_best_burst(buf_len, tlen,
+							   dst_maxburst,
+							   dst_addr_width);
+		ctcr &= ~STM32_MDMA_CTCR_DBURST_MASK;
+		ctcr |= STM32_MDMA_CTCR_DBURST((ilog2(dst_best_burst)));
+
+		/* Select bus */
+		src_addr = chan->dma_config.src_addr;
+		stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_SBUS,
+				   src_addr);
+
+		/* Set source address */
+		stm32_mdma_write(dmadev, STM32_MDMA_CSAR(chan->id), src_addr);
+		break;
+
+	default:
+		dev_err(chan2dev(chan), "Dma direction is not supported\n");
+		return -EINVAL;
+	}
+
+	*mdma_ccr = ccr;
+	*mdma_ctcr = ctcr;
+	*mdma_ctbr = ctbr;
+
+	return 0;
+}
+
+static void stm32_mdma_dump_hwdesc(struct stm32_mdma_chan *chan,
+				   struct stm32_mdma_hwdesc *hwdesc)
+{
+	dev_dbg(chan2dev(chan), "hwdesc:  0x%08x\n", (unsigned int)hwdesc);
+	dev_dbg(chan2dev(chan), "CTCR:    0x%08x\n", hwdesc->ctcr);
+	dev_dbg(chan2dev(chan), "CBNDTR:  0x%08x\n", hwdesc->cbndtr);
+	dev_dbg(chan2dev(chan), "CSAR:    0x%08x\n", hwdesc->csar);
+	dev_dbg(chan2dev(chan), "CDAR:    0x%08x\n", hwdesc->cdar);
+	dev_dbg(chan2dev(chan), "CBRUR:   0x%08x\n", hwdesc->cbrur);
+	dev_dbg(chan2dev(chan), "CLAR:    0x%08x\n", hwdesc->clar);
+	dev_dbg(chan2dev(chan), "CTBR:    0x%08x\n", hwdesc->ctbr);
+	dev_dbg(chan2dev(chan), "CMAR:    0x%08x\n", hwdesc->cmar);
+	dev_dbg(chan2dev(chan), "CMDR:    0x%08x\n\n", hwdesc->cmdr);
+}
+
+static void stm32_mdma_setup_hwdesc(struct stm32_mdma_chan *chan,
+				    struct stm32_mdma_desc *desc,
+				    enum dma_transfer_direction dir, u32 count,
+				    dma_addr_t src_addr, dma_addr_t dst_addr,
+				    u32 len, u32 ctcr, u32 ctbr, bool is_last,
+				    bool is_first, bool is_cyclic)
+{
+	struct stm32_mdma_chan_config *config = &chan->chan_config;
+	struct stm32_mdma_hwdesc *hwdesc;
+	u32 next = count + 1;
+
+	hwdesc = &desc->hwdesc[count];
+	hwdesc->ctcr = ctcr;
+	hwdesc->cbndtr &= ~(STM32_MDMA_CBNDTR_BRC_MK |
+			STM32_MDMA_CBNDTR_BRDUM |
+			STM32_MDMA_CBNDTR_BRSUM |
+			STM32_MDMA_CBNDTR_BNDT_MASK);
+	hwdesc->cbndtr |= STM32_MDMA_CBNDTR_BNDT(len);
+	hwdesc->csar = src_addr;
+	hwdesc->cdar = dst_addr;
+	hwdesc->cbrur = 0;
+	hwdesc->clar = desc->hwdesc_phys + next * sizeof(*hwdesc);
+	hwdesc->ctbr = ctbr;
+	hwdesc->cmar = config->mask_addr;
+	hwdesc->cmdr = config->mask_data;
+
+	if (is_last) {
+		if (is_cyclic)
+			hwdesc->clar = desc->hwdesc_phys;
+		else
+			hwdesc->clar = 0;
+	}
+
+	stm32_mdma_dump_hwdesc(chan, hwdesc);
+}
+
+static int stm32_mdma_setup_xfer(struct stm32_mdma_chan *chan,
+				 struct stm32_mdma_desc *desc,
+				 struct scatterlist *sgl, u32 sg_len,
+				 enum dma_transfer_direction direction)
+{
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	struct dma_slave_config *dma_config = &chan->dma_config;
+	struct scatterlist *sg;
+	dma_addr_t src_addr, dst_addr;
+	u32 ccr, ctcr, ctbr;
+	int i, ret = 0;
+
+	for_each_sg(sgl, sg, sg_len, i) {
+		if (sg_dma_len(sg) > STM32_MDMA_MAX_BLOCK_LEN) {
+			dev_err(chan2dev(chan), "Invalid block len\n");
+			return -EINVAL;
+		}
+
+		ret = stm32_mdma_set_xfer_param(chan, direction, &ccr, &ctcr,
+						&ctbr, sg_dma_len(sg));
+		if (ret < 0)
+			return ret;
+
+		if (direction == DMA_MEM_TO_DEV) {
+			src_addr = sg_dma_address(sg);
+			dst_addr = dma_config->dst_addr;
+			stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_SBUS,
+					   src_addr);
+		} else {
+			src_addr = dma_config->src_addr;
+			dst_addr = sg_dma_address(sg);
+			stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_DBUS,
+					   dst_addr);
+		}
+
+		stm32_mdma_setup_hwdesc(chan, desc, direction, i, src_addr,
+					dst_addr, sg_dma_len(sg), ctcr, ctbr,
+					i == sg_len - 1, i == 0, false);
+	}
+
+	/* Enable interrupts */
+	ccr &= ~STM32_MDMA_CCR_IRQ_MASK;
+	ccr |= STM32_MDMA_CCR_TEIE | STM32_MDMA_CCR_CTCIE;
+	if (sg_len > 1)
+		ccr |= STM32_MDMA_CCR_BTIE;
+	desc->ccr = ccr;
+
+	return 0;
+}
+
+static struct dma_async_tx_descriptor *
+stm32_mdma_prep_slave_sg(struct dma_chan *c, struct scatterlist *sgl,
+			 u32 sg_len, enum dma_transfer_direction direction,
+			 unsigned long flags, void *context)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	struct stm32_mdma_desc *desc;
+	int ret;
+
+	desc = stm32_mdma_alloc_desc(chan, sg_len);
+	if (!desc)
+		return NULL;
+
+	ret = stm32_mdma_setup_xfer(chan, desc, sgl, sg_len, direction);
+	if (ret < 0)
+		goto xfer_setup_err;
+
+	desc->cyclic = false;
+
+	return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
+
+xfer_setup_err:
+	dma_pool_free(chan->desc_pool, &desc->hwdesc, desc->hwdesc_phys);
+	kfree(desc);
+	return NULL;
+}
+
+static struct dma_async_tx_descriptor *
+stm32_mdma_prep_dma_cyclic(struct dma_chan *c, dma_addr_t buf_addr,
+			   size_t buf_len, size_t period_len,
+			   enum dma_transfer_direction direction,
+			   unsigned long flags)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	struct dma_slave_config *dma_config = &chan->dma_config;
+	struct stm32_mdma_desc *desc;
+	dma_addr_t src_addr, dst_addr;
+	u32 ccr, ctcr, ctbr, count;
+	int i, ret;
+
+	if (!buf_len || !period_len || period_len > STM32_MDMA_MAX_BLOCK_LEN) {
+		dev_err(chan2dev(chan), "Invalid buffer/period len\n");
+		return NULL;
+	}
+
+	if (buf_len % period_len) {
+		dev_err(chan2dev(chan), "buf_len not multiple of period_len\n");
+		return NULL;
+	}
+
+	/*
+	 * We allow to take more number of requests till DMA is
+	 * not started. The driver will loop over all requests.
+	 * Once DMA is started then new requests can be queued only after
+	 * terminating the DMA.
+	 */
+	if (chan->busy) {
+		dev_err(chan2dev(chan), "Request not allowed when dma busy\n");
+		return NULL;
+	}
+
+	count = buf_len / period_len;
+
+	desc = stm32_mdma_alloc_desc(chan, count);
+	if (!desc)
+		return NULL;
+
+	ret = stm32_mdma_set_xfer_param(chan, direction, &ccr, &ctcr, &ctbr,
+					period_len);
+	if (ret < 0)
+		goto xfer_setup_err;
+
+	/* Enable interrupts */
+	ccr &= ~STM32_MDMA_CCR_IRQ_MASK;
+	ccr |= STM32_MDMA_CCR_TEIE | STM32_MDMA_CCR_CTCIE | STM32_MDMA_CCR_BTIE;
+	desc->ccr = ccr;
+
+	/* Select bus */
+	if (direction == DMA_MEM_TO_DEV) {
+		src_addr = buf_addr;
+		stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_SBUS,
+				   src_addr);
+	} else {
+		dst_addr = buf_addr;
+		stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_DBUS,
+				   dst_addr);
+	}
+
+	/* Configure hwdesc list */
+	for (i = 0; i < count; i++) {
+		if (direction == DMA_MEM_TO_DEV) {
+			src_addr = buf_addr + i * period_len;
+			dst_addr = dma_config->dst_addr;
+		} else {
+			src_addr = dma_config->src_addr;
+			dst_addr = buf_addr + i * period_len;
+		}
+
+		stm32_mdma_setup_hwdesc(chan, desc, direction, i, src_addr,
+					dst_addr, period_len, ctcr, ctbr,
+					i == count - 1, i == 0, true);
+	}
+
+	desc->cyclic = true;
+
+	return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
+
+xfer_setup_err:
+	dma_pool_free(chan->desc_pool, &desc->hwdesc, desc->hwdesc_phys);
+	kfree(desc);
+	return NULL;
+}
+
+static struct dma_async_tx_descriptor *
+stm32_mdma_prep_dma_memcpy(struct dma_chan *c, dma_addr_t dest, dma_addr_t src,
+			   size_t len, unsigned long flags)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	enum dma_slave_buswidth max_width;
+	struct stm32_mdma_desc *desc;
+	struct stm32_mdma_hwdesc *hwdesc;
+	u32 ccr, ctcr, ctbr, cbndtr, count, max_burst, mdma_burst;
+	u32 best_burst, tlen;
+	size_t xfer_count, offset;
+	int i;
+
+	count = DIV_ROUND_UP(len, STM32_MDMA_MAX_BLOCK_LEN);
+	desc = stm32_mdma_alloc_desc(chan, count);
+	if (!desc)
+		return NULL;
+
+	ccr = stm32_mdma_read(dmadev, STM32_MDMA_CCR(chan->id));
+	ctcr = stm32_mdma_read(dmadev, STM32_MDMA_CTCR(chan->id));
+	ctbr = stm32_mdma_read(dmadev, STM32_MDMA_CTBR(chan->id));
+	cbndtr = stm32_mdma_read(dmadev, STM32_MDMA_CBNDTR(chan->id));
+
+	/* Enable sw req, some interrupts and clear other bits */
+	ccr &= ~(STM32_MDMA_CCR_WEX | STM32_MDMA_CCR_HEX |
+		 STM32_MDMA_CCR_BEX | STM32_MDMA_CCR_PL_MASK |
+		 STM32_MDMA_CCR_IRQ_MASK);
+	ccr |= STM32_MDMA_CCR_TEIE;
+
+	/* Enable SW request mode, dest/src inc and clear other bits */
+	ctcr &= ~(STM32_MDMA_CTCR_BWM | STM32_MDMA_CTCR_TRGM_MSK |
+		  STM32_MDMA_CTCR_PAM_MASK | STM32_MDMA_CTCR_PKE |
+		  STM32_MDMA_CTCR_TLEN_MSK | STM32_MDMA_CTCR_DBURST_MASK |
+		  STM32_MDMA_CTCR_SBURST_MASK | STM32_MDMA_CTCR_DINCOS_MASK |
+		  STM32_MDMA_CTCR_SINCOS_MASK | STM32_MDMA_CTCR_DSIZE_MASK |
+		  STM32_MDMA_CTCR_SSIZE_MASK | STM32_MDMA_CTCR_DINC_MASK |
+		  STM32_MDMA_CTCR_SINC_MASK);
+	ctcr |= STM32_MDMA_CTCR_SWRM | STM32_MDMA_CTCR_SINC(STM32_MDMA_INC) |
+		STM32_MDMA_CTCR_DINC(STM32_MDMA_INC);
+
+	/* Reset HW request */
+	ctbr &= ~STM32_MDMA_CTBR_TSEL_MASK;
+
+	/* Select bus */
+	stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_SBUS, src);
+	stm32_mdma_set_bus(dmadev, &ctbr, STM32_MDMA_CTBR_DBUS, dest);
+
+	/* Clear CBNDTR registers */
+	cbndtr &= ~(STM32_MDMA_CBNDTR_BRC_MK | STM32_MDMA_CBNDTR_BRDUM |
+			STM32_MDMA_CBNDTR_BRSUM | STM32_MDMA_CBNDTR_BNDT_MASK);
+
+	if (len <= STM32_MDMA_MAX_BLOCK_LEN) {
+		cbndtr |= STM32_MDMA_CBNDTR_BNDT(len);
+		if (len <= STM32_MDMA_MAX_BUF_LEN) {
+			/* Setup a buffer transfer */
+			tlen = len;
+			ccr |= STM32_MDMA_CCR_TCIE | STM32_MDMA_CCR_CTCIE;
+			ctcr |= STM32_MDMA_CTCR_TRGM(STM32_MDMA_BUFFER);
+			ctcr |= STM32_MDMA_CTCR_TLEN((tlen - 1));
+		} else {
+			/* Setup a block transfer */
+			tlen = STM32_MDMA_MAX_BUF_LEN;
+			ccr |= STM32_MDMA_CCR_BTIE | STM32_MDMA_CCR_CTCIE;
+			ctcr |= STM32_MDMA_CTCR_TRGM(STM32_MDMA_BLOCK);
+			ctcr |= STM32_MDMA_CTCR_TLEN(tlen - 1);
+		}
+
+		/* Set best burst size */
+		max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+		max_burst = tlen / max_width;
+		best_burst = stm32_mdma_get_best_burst(len, tlen, max_burst,
+						       max_width);
+
+		mdma_burst = ilog2(best_burst);
+
+		ctcr |= STM32_MDMA_CTCR_DBURST(mdma_burst) |
+			STM32_MDMA_CTCR_SBURST(mdma_burst);
+
+		/* Prepare hardware descriptor */
+		hwdesc = desc->hwdesc;
+		hwdesc->ctcr = ctcr;
+		hwdesc->cbndtr = cbndtr;
+		hwdesc->csar = src;
+		hwdesc->cdar = dest;
+		hwdesc->cbrur = 0;
+		hwdesc->clar = 0;
+		hwdesc->ctbr = ctbr;
+		hwdesc->cmar = 0;
+		hwdesc->cmdr = 0;
+
+		stm32_mdma_dump_hwdesc(chan, hwdesc);
+	} else {
+		/* Setup a LLI transfer */
+		ctcr |= STM32_MDMA_CTCR_TRGM(STM32_MDMA_LINKED_LIST) |
+			STM32_MDMA_CTCR_TLEN((STM32_MDMA_MAX_BUF_LEN - 1));
+		ccr |= STM32_MDMA_CCR_BTIE | STM32_MDMA_CCR_CTCIE;
+		tlen = STM32_MDMA_MAX_BUF_LEN;
+
+		for (i = 0, offset = 0; offset < len;
+		     i++, offset += xfer_count) {
+			xfer_count = min_t(size_t, len - offset,
+					   STM32_MDMA_MAX_BLOCK_LEN);
+
+			/* Set best burst size */
+			max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+			max_burst = STM32_MDMA_MAX_BUF_LEN / max_width;
+			best_burst = stm32_mdma_get_best_burst(xfer_count, tlen,
+							       max_burst,
+							       max_width);
+			mdma_burst = ilog2(best_burst);
+
+			ctcr &= ~(STM32_MDMA_CTCR_DBURST_MASK |
+				  STM32_MDMA_CTCR_SBURST_MASK);
+			ctcr |= STM32_MDMA_CTCR_DBURST(mdma_burst) |
+				STM32_MDMA_CTCR_SBURST(mdma_burst);
+
+			/* Prepare hardware descriptor */
+			stm32_mdma_setup_hwdesc(chan, desc, DMA_MEM_TO_MEM, i,
+						src + offset, dest + offset,
+						xfer_count, ctcr, ctbr,
+						i == count - 1, i == 0, false);
+		}
+	}
+
+	desc->ccr = ccr;
+
+	desc->cyclic = false;
+
+	return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
+}
+
+static void stm32_mdma_dump_reg(struct stm32_mdma_chan *chan)
+{
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+
+	dev_dbg(chan2dev(chan), "CCR:     0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CCR(chan->id)));
+	dev_dbg(chan2dev(chan), "CTCR:    0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CTCR(chan->id)));
+	dev_dbg(chan2dev(chan), "CBNDTR:  0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CBNDTR(chan->id)));
+	dev_dbg(chan2dev(chan), "CSAR:    0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CSAR(chan->id)));
+	dev_dbg(chan2dev(chan), "CDAR:    0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CDAR(chan->id)));
+	dev_dbg(chan2dev(chan), "CBRUR:   0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CBRUR(chan->id)));
+	dev_dbg(chan2dev(chan), "CLAR:    0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CLAR(chan->id)));
+	dev_dbg(chan2dev(chan), "CTBR:    0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CTBR(chan->id)));
+	dev_dbg(chan2dev(chan), "CMAR:    0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CMAR(chan->id)));
+	dev_dbg(chan2dev(chan), "CMDR:    0x%08x\n",
+		stm32_mdma_read(dmadev, STM32_MDMA_CMDR(chan->id)));
+}
+
+static void stm32_mdma_start_transfer(struct stm32_mdma_chan *chan)
+{
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	struct virt_dma_desc *vdesc;
+	struct stm32_mdma_hwdesc *hwdesc;
+	u32 id = chan->id;
+	u32 status, reg;
+
+	vdesc = vchan_next_desc(&chan->vchan);
+	if (!vdesc) {
+		chan->desc = NULL;
+		return;
+	}
+
+	chan->desc = to_stm32_mdma_desc(vdesc);
+	hwdesc = chan->desc->hwdesc;
+	chan->curr_hwdesc = 0;
+
+	stm32_mdma_write(dmadev, STM32_MDMA_CCR(id), chan->desc->ccr);
+	stm32_mdma_write(dmadev, STM32_MDMA_CTCR(id), hwdesc->ctcr);
+	stm32_mdma_write(dmadev, STM32_MDMA_CBNDTR(id), hwdesc->cbndtr);
+	stm32_mdma_write(dmadev, STM32_MDMA_CSAR(id), hwdesc->csar);
+	stm32_mdma_write(dmadev, STM32_MDMA_CDAR(id), hwdesc->cdar);
+	stm32_mdma_write(dmadev, STM32_MDMA_CBRUR(id), hwdesc->cbrur);
+	stm32_mdma_write(dmadev, STM32_MDMA_CLAR(id), hwdesc->clar);
+	stm32_mdma_write(dmadev, STM32_MDMA_CTBR(id), hwdesc->ctbr);
+	stm32_mdma_write(dmadev, STM32_MDMA_CMAR(id), hwdesc->cmar);
+	stm32_mdma_write(dmadev, STM32_MDMA_CMDR(id), hwdesc->cmdr);
+
+	/* Clear interrupt status if it is there */
+	status = stm32_mdma_read(dmadev, STM32_MDMA_CISR(id));
+	if (status)
+		stm32_mdma_set_bits(dmadev, STM32_MDMA_CIFCR(id), status);
+
+	stm32_mdma_dump_reg(chan);
+
+	/* Start DMA */
+	stm32_mdma_set_bits(dmadev, STM32_MDMA_CCR(id), STM32_MDMA_CCR_EN);
+
+	/* Set SW request in case of MEM2MEM transfer */
+	if (hwdesc->ctcr & STM32_MDMA_CTCR_SWRM) {
+		reg = STM32_MDMA_CCR(id);
+		stm32_mdma_set_bits(dmadev, reg, STM32_MDMA_CCR_SWRQ);
+	}
+
+	chan->busy = true;
+
+	dev_dbg(chan2dev(chan), "vchan %p: started\n", &chan->vchan);
+}
+
+static void stm32_mdma_issue_pending(struct dma_chan *c)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	unsigned long flags;
+
+	spin_lock_irqsave(&chan->vchan.lock, flags);
+
+	if (!vchan_issue_pending(&chan->vchan))
+		goto end;
+
+	dev_dbg(chan2dev(chan), "vchan %p: issued\n", &chan->vchan);
+
+	if (!chan->desc && !chan->busy)
+		stm32_mdma_start_transfer(chan);
+
+end:
+	spin_unlock_irqrestore(&chan->vchan.lock, flags);
+}
+
+static int stm32_mdma_pause(struct dma_chan *c)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&chan->vchan.lock, flags);
+	ret = stm32_mdma_disable_chan(chan);
+	spin_unlock_irqrestore(&chan->vchan.lock, flags);
+
+	if (!ret)
+		dev_dbg(chan2dev(chan), "vchan %p: pause\n", &chan->vchan);
+
+	return ret;
+}
+
+static int stm32_mdma_resume(struct dma_chan *c)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	struct stm32_mdma_hwdesc *hwdesc;
+	unsigned long flags;
+	u32 status, reg;
+
+	hwdesc = &chan->desc->hwdesc[chan->curr_hwdesc];
+
+	spin_lock_irqsave(&chan->vchan.lock, flags);
+
+	/* Re-configure control register */
+	stm32_mdma_write(dmadev, STM32_MDMA_CCR(chan->id), chan->desc->ccr);
+
+	/* Clear interrupt status if it is there */
+	status = stm32_mdma_read(dmadev, STM32_MDMA_CISR(chan->id));
+	if (status)
+		stm32_mdma_set_bits(dmadev, STM32_MDMA_CIFCR(chan->id), status);
+
+	stm32_mdma_dump_reg(chan);
+
+	/* Re-start DMA */
+	reg = STM32_MDMA_CCR(chan->id);
+	stm32_mdma_set_bits(dmadev, reg, STM32_MDMA_CCR_EN);
+
+	/* Set SW request in case of MEM2MEM transfer */
+	if (hwdesc->ctcr & STM32_MDMA_CTCR_SWRM)
+		stm32_mdma_set_bits(dmadev, reg, STM32_MDMA_CCR_SWRQ);
+
+	spin_unlock_irqrestore(&chan->vchan.lock, flags);
+
+	dev_dbg(chan2dev(chan), "vchan %p: resume\n", &chan->vchan);
+
+	return 0;
+}
+
+static int stm32_mdma_terminate_all(struct dma_chan *c)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	unsigned long flags;
+	LIST_HEAD(head);
+
+	spin_lock_irqsave(&chan->vchan.lock, flags);
+	if (chan->busy) {
+		stm32_mdma_stop(chan);
+		chan->desc = NULL;
+	}
+	vchan_get_all_descriptors(&chan->vchan, &head);
+	spin_unlock_irqrestore(&chan->vchan.lock, flags);
+
+	vchan_dma_desc_free_list(&chan->vchan, &head);
+
+	return 0;
+}
+
+static void stm32_mdma_synchronize(struct dma_chan *c)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+
+	vchan_synchronize(&chan->vchan);
+}
+
+static int stm32_mdma_slave_config(struct dma_chan *c,
+				   struct dma_slave_config *config)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+
+	memcpy(&chan->dma_config, config, sizeof(*config));
+
+	return 0;
+}
+
+static size_t stm32_mdma_desc_residue(struct stm32_mdma_chan *chan,
+				      struct stm32_mdma_desc *desc,
+				      u32 curr_hwdesc)
+{
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	struct stm32_mdma_hwdesc *hwdesc = desc->hwdesc;
+	u32 cbndtr, residue, modulo, burst_size;
+	int i;
+
+	residue = 0;
+	for (i = curr_hwdesc + 1; i < desc->count; i++) {
+		hwdesc = &desc->hwdesc[i];
+		residue += STM32_MDMA_CBNDTR_BNDT(hwdesc->cbndtr);
+	}
+	cbndtr = stm32_mdma_read(dmadev, STM32_MDMA_CBNDTR(chan->id));
+	residue += cbndtr & STM32_MDMA_CBNDTR_BNDT_MASK;
+
+	if (!chan->mem_burst)
+		return residue;
+
+	burst_size = chan->mem_burst * chan->mem_width;
+	modulo = residue % burst_size;
+	if (modulo)
+		residue = residue - modulo + burst_size;
+
+	return residue;
+}
+
+static enum dma_status stm32_mdma_tx_status(struct dma_chan *c,
+					    dma_cookie_t cookie,
+					    struct dma_tx_state *state)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	struct virt_dma_desc *vdesc;
+	enum dma_status status;
+	unsigned long flags;
+	u32 residue = 0;
+
+	status = dma_cookie_status(c, cookie, state);
+	if ((status == DMA_COMPLETE) || (!state))
+		return status;
+
+	spin_lock_irqsave(&chan->vchan.lock, flags);
+
+	vdesc = vchan_find_desc(&chan->vchan, cookie);
+	if (chan->desc && cookie == chan->desc->vdesc.tx.cookie)
+		residue = stm32_mdma_desc_residue(chan, chan->desc,
+						  chan->curr_hwdesc);
+	else if (vdesc)
+		residue = stm32_mdma_desc_residue(chan,
+						  to_stm32_mdma_desc(vdesc), 0);
+	dma_set_residue(state, residue);
+
+	spin_unlock_irqrestore(&chan->vchan.lock, flags);
+
+	return status;
+}
+
+static void stm32_mdma_xfer_end(struct stm32_mdma_chan *chan)
+{
+	list_del(&chan->desc->vdesc.node);
+	vchan_cookie_complete(&chan->desc->vdesc);
+	chan->desc = NULL;
+	chan->busy = false;
+
+	/* Start the next transfer if this driver has a next desc */
+	stm32_mdma_start_transfer(chan);
+}
+
+static irqreturn_t stm32_mdma_irq_handler(int irq, void *devid)
+{
+	struct stm32_mdma_device *dmadev = devid;
+	struct stm32_mdma_chan *chan = devid;
+	u32 reg, id, ien, status, flag;
+
+	/* Find out which channel generates the interrupt */
+	status = readl_relaxed(dmadev->base + STM32_MDMA_GISR0);
+	if (status) {
+		id = __ffs(status);
+	} else {
+		status = readl_relaxed(dmadev->base + STM32_MDMA_GISR1);
+		if (!status) {
+			dev_dbg(mdma2dev(dmadev), "spurious it\n");
+			return IRQ_NONE;
+		}
+		id = __ffs(status);
+		/*
+		 * As GISR0 provides status for channel id from 0 to 31,
+		 * so GISR1 provides status for channel id from 32 to 62
+		 */
+		id += 32;
+	}
+
+	chan = &dmadev->chan[id];
+	if (!chan) {
+		dev_err(chan2dev(chan), "MDMA channel not initialized\n");
+		goto exit;
+	}
+
+	/* Handle interrupt for the channel */
+	spin_lock(&chan->vchan.lock);
+	status = stm32_mdma_read(dmadev, STM32_MDMA_CISR(chan->id));
+	ien = stm32_mdma_read(dmadev, STM32_MDMA_CCR(chan->id));
+	ien &= STM32_MDMA_CCR_IRQ_MASK;
+	ien >>= 1;
+
+	if (!(status & ien)) {
+		spin_unlock(&chan->vchan.lock);
+		dev_dbg(chan2dev(chan),
+			"spurious it (status=0x%04x, ien=0x%04x)\n",
+			status, ien);
+		return IRQ_NONE;
+	}
+
+	flag = __ffs(status & ien);
+	reg = STM32_MDMA_CIFCR(chan->id);
+
+	switch (1 << flag) {
+	case STM32_MDMA_CISR_TEIF:
+		id = chan->id;
+		status = readl_relaxed(dmadev->base + STM32_MDMA_CESR(id));
+		dev_err(chan2dev(chan), "Transfer Err: stat=0x%08x\n", status);
+		stm32_mdma_set_bits(dmadev, reg, STM32_MDMA_CIFCR_CTEIF);
+		break;
+
+	case STM32_MDMA_CISR_CTCIF:
+		stm32_mdma_set_bits(dmadev, reg, STM32_MDMA_CIFCR_CCTCIF);
+		stm32_mdma_xfer_end(chan);
+		break;
+
+	case STM32_MDMA_CISR_BRTIF:
+		stm32_mdma_set_bits(dmadev, reg, STM32_MDMA_CIFCR_CBRTIF);
+		break;
+
+	case STM32_MDMA_CISR_BTIF:
+		stm32_mdma_set_bits(dmadev, reg, STM32_MDMA_CIFCR_CBTIF);
+		chan->curr_hwdesc++;
+		if (chan->desc && chan->desc->cyclic) {
+			if (chan->curr_hwdesc == chan->desc->count)
+				chan->curr_hwdesc = 0;
+			vchan_cyclic_callback(&chan->desc->vdesc);
+		}
+		break;
+
+	case STM32_MDMA_CISR_TCIF:
+		stm32_mdma_set_bits(dmadev, reg, STM32_MDMA_CIFCR_CLTCIF);
+		break;
+
+	default:
+		dev_err(chan2dev(chan), "it %d unhandled (status=0x%04x)\n",
+			1 << flag, status);
+	}
+
+	spin_unlock(&chan->vchan.lock);
+
+exit:
+	return IRQ_HANDLED;
+}
+
+static int stm32_mdma_alloc_chan_resources(struct dma_chan *c)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	int ret;
+
+	chan->desc_pool = dmam_pool_create(dev_name(&c->dev->device),
+					   c->device->dev,
+					   sizeof(struct stm32_mdma_hwdesc),
+					  __alignof__(struct stm32_mdma_hwdesc),
+					   0);
+	if (!chan->desc_pool) {
+		dev_err(chan2dev(chan), "failed to allocate descriptor pool\n");
+		return -ENOMEM;
+	}
+
+	ret = clk_prepare_enable(dmadev->clk);
+	if (ret < 0) {
+		dev_err(chan2dev(chan), "clk_prepare_enable failed: %d\n", ret);
+		return ret;
+	}
+
+	ret = stm32_mdma_disable_chan(chan);
+	if (ret < 0)
+		clk_disable_unprepare(dmadev->clk);
+
+	return ret;
+}
+
+static void stm32_mdma_free_chan_resources(struct dma_chan *c)
+{
+	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
+	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
+	unsigned long flags;
+
+	dev_dbg(chan2dev(chan), "Freeing channel %d\n", chan->id);
+
+	if (chan->busy) {
+		spin_lock_irqsave(&chan->vchan.lock, flags);
+		stm32_mdma_stop(chan);
+		chan->desc = NULL;
+		spin_unlock_irqrestore(&chan->vchan.lock, flags);
+	}
+
+	clk_disable_unprepare(dmadev->clk);
+	vchan_free_chan_resources(to_virt_chan(c));
+	dmam_pool_destroy(chan->desc_pool);
+	chan->desc_pool = NULL;
+}
+
+static struct dma_chan *stm32_mdma_of_xlate(struct of_phandle_args *dma_spec,
+					    struct of_dma *ofdma)
+{
+	struct stm32_mdma_device *dmadev = ofdma->of_dma_data;
+	struct stm32_mdma_chan *chan;
+	struct dma_chan *c;
+	struct stm32_mdma_chan_config config;
+
+	if (dma_spec->args_count < 5) {
+		dev_err(mdma2dev(dmadev), "Bad number of args\n");
+		return NULL;
+	}
+
+	config.request = dma_spec->args[0];
+	config.priority_level = dma_spec->args[1];
+	config.transfer_config = dma_spec->args[2];
+	config.mask_addr = dma_spec->args[3];
+	config.mask_data = dma_spec->args[4];
+
+	if (config.request >= dmadev->nr_requests) {
+		dev_err(mdma2dev(dmadev), "Bad request line\n");
+		return NULL;
+	}
+
+	if (config.priority_level > STM32_MDMA_VERY_HIGH_PRIORITY) {
+		dev_err(mdma2dev(dmadev), "Priority level not supported\n");
+		return NULL;
+	}
+
+	c = dma_get_any_slave_channel(&dmadev->ddev);
+	if (!c) {
+		dev_err(mdma2dev(dmadev), "No more channel avalaible\n");
+		return NULL;
+	}
+
+	chan = to_stm32_mdma_chan(c);
+	chan->chan_config = config;
+
+	return c;
+}
+
+static const struct of_device_id stm32_mdma_of_match[] = {
+	{ .compatible = "st,stm32h7-mdma", },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, stm32_mdma_of_match);
+
+static int stm32_mdma_probe(struct platform_device *pdev)
+{
+	struct stm32_mdma_chan *chan;
+	struct stm32_mdma_device *dmadev;
+	struct dma_device *dd;
+	struct device_node *of_node;
+	struct resource *res;
+	u32 nr_channels, nr_requests;
+	int i, count, ret;
+
+	of_node = pdev->dev.of_node;
+	if (!of_node)
+		return -ENODEV;
+
+	ret = device_property_read_u32(&pdev->dev, "dma-channels",
+				       &nr_channels);
+	if (ret) {
+		nr_channels = STM32_MDMA_MAX_CHANNELS;
+		dev_warn(&pdev->dev, "MDMA defaulting on %i channels\n",
+			 nr_channels);
+	}
+
+	ret = device_property_read_u32(&pdev->dev, "dma-requests",
+				       &nr_requests);
+	if (ret) {
+		nr_requests = STM32_MDMA_MAX_REQUESTS;
+		dev_warn(&pdev->dev, "MDMA defaulting on %i request lines\n",
+			 nr_requests);
+	}
+
+	count = of_property_count_u32_elems(of_node, "st,ahb-addr-masks");
+	if (count < 0)
+		count = 0;
+
+	dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev) + sizeof(u32) * count,
+			      GFP_KERNEL);
+	if (!dmadev)
+		return -ENOMEM;
+
+	dmadev->nr_channels = nr_channels;
+	dmadev->nr_requests = nr_requests;
+	of_property_read_u32_array(of_node, "st,ahb-addr-masks",
+				   dmadev->ahb_addr_masks,
+				   count);
+	dmadev->nr_ahb_addr_masks = count;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	dmadev->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(dmadev->base))
+		return PTR_ERR(dmadev->base);
+
+	dmadev->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(dmadev->clk)) {
+		dev_err(&pdev->dev, "Error: Missing controller clock\n");
+		return PTR_ERR(dmadev->clk);
+	}
+
+	dmadev->rst = devm_reset_control_get(&pdev->dev, NULL);
+	if (!IS_ERR(dmadev->rst)) {
+		reset_control_assert(dmadev->rst);
+		udelay(2);
+		reset_control_deassert(dmadev->rst);
+	}
+
+	dd = &dmadev->ddev;
+	dma_cap_set(DMA_SLAVE, dd->cap_mask);
+	dma_cap_set(DMA_PRIVATE, dd->cap_mask);
+	dma_cap_set(DMA_CYCLIC, dd->cap_mask);
+	dma_cap_set(DMA_MEMCPY, dd->cap_mask);
+	dd->device_alloc_chan_resources = stm32_mdma_alloc_chan_resources;
+	dd->device_free_chan_resources = stm32_mdma_free_chan_resources;
+	dd->device_tx_status = stm32_mdma_tx_status;
+	dd->device_issue_pending = stm32_mdma_issue_pending;
+	dd->device_prep_slave_sg = stm32_mdma_prep_slave_sg;
+	dd->device_prep_dma_cyclic = stm32_mdma_prep_dma_cyclic;
+	dd->device_prep_dma_memcpy = stm32_mdma_prep_dma_memcpy;
+	dd->device_config = stm32_mdma_slave_config;
+	dd->device_pause = stm32_mdma_pause;
+	dd->device_resume = stm32_mdma_resume;
+	dd->device_terminate_all = stm32_mdma_terminate_all;
+	dd->device_synchronize = stm32_mdma_synchronize;
+	dd->src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
+		BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
+		BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) |
+		BIT(DMA_SLAVE_BUSWIDTH_8_BYTES);
+	dd->dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
+		BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
+		BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) |
+		BIT(DMA_SLAVE_BUSWIDTH_8_BYTES);
+	dd->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV) |
+		BIT(DMA_MEM_TO_MEM);
+	dd->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
+	dd->max_burst = STM32_MDMA_MAX_BURST;
+	dd->dev = &pdev->dev;
+	INIT_LIST_HEAD(&dd->channels);
+
+	for (i = 0; i < dmadev->nr_channels; i++) {
+		chan = &dmadev->chan[i];
+		chan->id = i;
+		chan->vchan.desc_free = stm32_mdma_desc_free;
+		vchan_init(&chan->vchan, dd);
+	}
+
+	dmadev->irq = platform_get_irq(pdev, 0);
+	if (dmadev->irq < 0) {
+		dev_err(&pdev->dev, "failed to get IRQ\n");
+		return dmadev->irq;
+	}
+
+	ret = devm_request_irq(&pdev->dev, dmadev->irq, stm32_mdma_irq_handler,
+			       0, dev_name(&pdev->dev), dmadev);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to request IRQ\n");
+		return ret;
+	}
+
+	ret = dma_async_device_register(dd);
+	if (ret)
+		return ret;
+
+	ret = of_dma_controller_register(of_node, stm32_mdma_of_xlate, dmadev);
+	if (ret < 0) {
+		dev_err(&pdev->dev,
+			"STM32 MDMA DMA OF registration failed %d\n", ret);
+		goto err_unregister;
+	}
+
+	platform_set_drvdata(pdev, dmadev);
+
+	dev_info(&pdev->dev, "STM32 MDMA driver registered\n");
+
+	return 0;
+
+err_unregister:
+	dma_async_device_unregister(dd);
+
+	return ret;
+}
+
+static struct platform_driver stm32_mdma_driver = {
+	.driver = {
+		.name = "stm32-mdma",
+		.of_match_table = stm32_mdma_of_match,
+	},
+};
+
+static int __init stm32_mdma_init(void)
+{
+	return platform_driver_probe(&stm32_mdma_driver, stm32_mdma_probe);
+}
+
+subsys_initcall(stm32_mdma_init);
+
+MODULE_DESCRIPTION("Driver for STM32 MDMA controller");
+MODULE_AUTHOR("M'boumba Cedric Madianga <cedric.madianga@gmail.com>");
+MODULE_AUTHOR("Pierre-Yves Mordret <pierre-yves.mordret@st.com>");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 26+ messages in thread

* [PATCH v3 3/4] ARM: dts: stm32: Add MDMA support for STM32H743 SoC
@ 2017-07-26  9:48   ` Pierre-Yves MORDRET
  0 siblings, 0 replies; 26+ messages in thread
From: Pierre-Yves MORDRET @ 2017-07-26  9:48 UTC (permalink / raw)
  To: Vinod Koul, Rob Herring, Mark Rutland, Maxime Coquelin,
	Alexandre Torgue, Russell King, Dan Williams,
	M'boumba Cedric Madianga, Fabrice GASNIER, Herbert Xu,
	Fabien DESSENNE, Amelie Delaunay, Pierre-Yves MORDRET, dmaengine,
	devicetree, linux-arm-kernel, linux-kernel

This patch adds MDMA support for STM32H743 SoC.

Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
---
 Version history:
    v3:
        * None
    v2:
        * Add MDMA support in DT for H7
---
---
 arch/arm/boot/dts/stm32h743.dtsi | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/arm/boot/dts/stm32h743.dtsi b/arch/arm/boot/dts/stm32h743.dtsi
index 36a99db..af44eae 100644
--- a/arch/arm/boot/dts/stm32h743.dtsi
+++ b/arch/arm/boot/dts/stm32h743.dtsi
@@ -82,6 +82,16 @@
 			interrupts = <50>;
 			clocks = <&timer_clk>;
 		};
+
+		mdma1: dma@52000000 {
+			compatible = "st,stm32h7-mdma";
+			reg = <0x52000000 0x1000>;
+			interrupts = <122>;
+			clocks = <&timer_clk>;
+			#dma-cells = <5>;
+			dma-channels = <16>;
+			dma-requests = <32>;
+		};
 	};
 };
 
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 26+ messages in thread

* [PATCH v3 3/4] ARM: dts: stm32: Add MDMA support for STM32H743 SoC
@ 2017-07-26  9:48   ` Pierre-Yves MORDRET
  0 siblings, 0 replies; 26+ messages in thread
From: Pierre-Yves MORDRET @ 2017-07-26  9:48 UTC (permalink / raw)
  To: Vinod Koul, Rob Herring, Mark Rutland, Maxime Coquelin,
	Alexandre Torgue, Russell King, Dan Williams,
	M'boumba Cedric Madianga, Fabrice GASNIER, Herbert Xu,
	Fabien DESSENNE, Amelie Delaunay, Pierre-Yves MORDRET,
	dmaengine-u79uwXL29TY76Z2rM5mHXA,
	devicetree-u79uwXL29TY76Z2rM5mHXA,
	linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA

This patch adds MDMA support for STM32H743 SoC.

Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret-qxv4g6HH51o@public.gmane.org>
---
 Version history:
    v3:
        * None
    v2:
        * Add MDMA support in DT for H7
---
---
 arch/arm/boot/dts/stm32h743.dtsi | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/arm/boot/dts/stm32h743.dtsi b/arch/arm/boot/dts/stm32h743.dtsi
index 36a99db..af44eae 100644
--- a/arch/arm/boot/dts/stm32h743.dtsi
+++ b/arch/arm/boot/dts/stm32h743.dtsi
@@ -82,6 +82,16 @@
 			interrupts = <50>;
 			clocks = <&timer_clk>;
 		};
+
+		mdma1: dma@52000000 {
+			compatible = "st,stm32h7-mdma";
+			reg = <0x52000000 0x1000>;
+			interrupts = <122>;
+			clocks = <&timer_clk>;
+			#dma-cells = <5>;
+			dma-channels = <16>;
+			dma-requests = <32>;
+		};
 	};
 };
 
-- 
2.7.4

--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

^ permalink raw reply related	[flat|nested] 26+ messages in thread

* [PATCH v3 3/4] ARM: dts: stm32: Add MDMA support for STM32H743 SoC
@ 2017-07-26  9:48   ` Pierre-Yves MORDRET
  0 siblings, 0 replies; 26+ messages in thread
From: Pierre-Yves MORDRET @ 2017-07-26  9:48 UTC (permalink / raw)
  To: linux-arm-kernel

This patch adds MDMA support for STM32H743 SoC.

Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
---
 Version history:
    v3:
        * None
    v2:
        * Add MDMA support in DT for H7
---
---
 arch/arm/boot/dts/stm32h743.dtsi | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/arm/boot/dts/stm32h743.dtsi b/arch/arm/boot/dts/stm32h743.dtsi
index 36a99db..af44eae 100644
--- a/arch/arm/boot/dts/stm32h743.dtsi
+++ b/arch/arm/boot/dts/stm32h743.dtsi
@@ -82,6 +82,16 @@
 			interrupts = <50>;
 			clocks = <&timer_clk>;
 		};
+
+		mdma1: dma at 52000000 {
+			compatible = "st,stm32h7-mdma";
+			reg = <0x52000000 0x1000>;
+			interrupts = <122>;
+			clocks = <&timer_clk>;
+			#dma-cells = <5>;
+			dma-channels = <16>;
+			dma-requests = <32>;
+		};
 	};
 };
 
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 26+ messages in thread

* [PATCH v3 4/4] ARM: configs: stm32: Add MDMA support in STM32 defconfig
@ 2017-07-26  9:48   ` Pierre-Yves MORDRET
  0 siblings, 0 replies; 26+ messages in thread
From: Pierre-Yves MORDRET @ 2017-07-26  9:48 UTC (permalink / raw)
  To: Vinod Koul, Rob Herring, Mark Rutland, Maxime Coquelin,
	Alexandre Torgue, Russell King, Dan Williams,
	M'boumba Cedric Madianga, Fabrice GASNIER, Herbert Xu,
	Fabien DESSENNE, Amelie Delaunay, Pierre-Yves MORDRET, dmaengine,
	devicetree, linux-arm-kernel, linux-kernel

This patch adds MDMA support in STM32 defconfig file

Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
---
 Version history:
    v3:
        * None
    v2:
        * Add MDMA support in STM32 defconfig
---
---
 arch/arm/configs/stm32_defconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/configs/stm32_defconfig b/arch/arm/configs/stm32_defconfig
index 90e5c46..dd8919b 100644
--- a/arch/arm/configs/stm32_defconfig
+++ b/arch/arm/configs/stm32_defconfig
@@ -67,6 +67,7 @@ CONFIG_RTC_CLASS=y
 CONFIG_RTC_DRV_STM32=y
 CONFIG_DMADEVICES=y
 CONFIG_STM32_DMA=y
+CONFIG_STM32_MDMA=y
 CONFIG_IIO=y
 CONFIG_STM32_ADC_CORE=y
 CONFIG_STM32_ADC=y
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 26+ messages in thread

* [PATCH v3 4/4] ARM: configs: stm32: Add MDMA support in STM32 defconfig
@ 2017-07-26  9:48   ` Pierre-Yves MORDRET
  0 siblings, 0 replies; 26+ messages in thread
From: Pierre-Yves MORDRET @ 2017-07-26  9:48 UTC (permalink / raw)
  To: Vinod Koul, Rob Herring, Mark Rutland, Maxime Coquelin,
	Alexandre Torgue, Russell King, Dan Williams,
	M'boumba Cedric Madianga, Fabrice GASNIER, Herbert Xu,
	Fabien DESSENNE, Amelie Delaunay, Pierre-Yves MORDRET,
	dmaengine-u79uwXL29TY76Z2rM5mHXA,
	devicetree-u79uwXL29TY76Z2rM5mHXA,
	linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA

This patch adds MDMA support in STM32 defconfig file

Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret-qxv4g6HH51o@public.gmane.org>
---
 Version history:
    v3:
        * None
    v2:
        * Add MDMA support in STM32 defconfig
---
---
 arch/arm/configs/stm32_defconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/configs/stm32_defconfig b/arch/arm/configs/stm32_defconfig
index 90e5c46..dd8919b 100644
--- a/arch/arm/configs/stm32_defconfig
+++ b/arch/arm/configs/stm32_defconfig
@@ -67,6 +67,7 @@ CONFIG_RTC_CLASS=y
 CONFIG_RTC_DRV_STM32=y
 CONFIG_DMADEVICES=y
 CONFIG_STM32_DMA=y
+CONFIG_STM32_MDMA=y
 CONFIG_IIO=y
 CONFIG_STM32_ADC_CORE=y
 CONFIG_STM32_ADC=y
-- 
2.7.4

--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

^ permalink raw reply related	[flat|nested] 26+ messages in thread

* [PATCH v3 4/4] ARM: configs: stm32: Add MDMA support in STM32 defconfig
@ 2017-07-26  9:48   ` Pierre-Yves MORDRET
  0 siblings, 0 replies; 26+ messages in thread
From: Pierre-Yves MORDRET @ 2017-07-26  9:48 UTC (permalink / raw)
  To: linux-arm-kernel

This patch adds MDMA support in STM32 defconfig file

Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
---
 Version history:
    v3:
        * None
    v2:
        * Add MDMA support in STM32 defconfig
---
---
 arch/arm/configs/stm32_defconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/configs/stm32_defconfig b/arch/arm/configs/stm32_defconfig
index 90e5c46..dd8919b 100644
--- a/arch/arm/configs/stm32_defconfig
+++ b/arch/arm/configs/stm32_defconfig
@@ -67,6 +67,7 @@ CONFIG_RTC_CLASS=y
 CONFIG_RTC_DRV_STM32=y
 CONFIG_DMADEVICES=y
 CONFIG_STM32_DMA=y
+CONFIG_STM32_MDMA=y
 CONFIG_IIO=y
 CONFIG_STM32_ADC_CORE=y
 CONFIG_STM32_ADC=y
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 26+ messages in thread

* Re: [PATCH v3 2/4] dmaengine: Add STM32 MDMA driver
  2017-07-26  9:48   ` Pierre-Yves MORDRET
@ 2017-08-16 16:47     ` Vinod Koul
  -1 siblings, 0 replies; 26+ messages in thread
From: Vinod Koul @ 2017-08-16 16:47 UTC (permalink / raw)
  To: Pierre-Yves MORDRET
  Cc: Rob Herring, Mark Rutland, Maxime Coquelin, Alexandre Torgue,
	Russell King, Dan Williams, M'boumba Cedric Madianga,
	Fabrice GASNIER, Herbert Xu, Fabien DESSENNE, Amelie Delaunay,
	dmaengine, devicetree, linux-arm-kernel, linux-kernel

On Wed, Jul 26, 2017 at 11:48:20AM +0200, Pierre-Yves MORDRET wrote:

> +/* MDMA Channel x transfer configuration register */
> +#define STM32_MDMA_CTCR(x)		(0x50 + 0x40 * (x))
> +#define STM32_MDMA_CTCR_BWM		BIT(31)
> +#define STM32_MDMA_CTCR_SWRM		BIT(30)
> +#define STM32_MDMA_CTCR_TRGM_MSK	GENMASK(29, 28)
> +#define STM32_MDMA_CTCR_TRGM(n)		(((n) & 0x3) << 28)
> +#define STM32_MDMA_CTCR_TRGM_GET(n)	(((n) & STM32_MDMA_CTCR_TRGM_MSK) >> 28)

OK this seems oft repeated here.

So you are trying to extract the bit values and set the bit value, so why
not this do generically...

#define STM32_MDMA_SHIFT(n)		(ffs(n) - 1))
#define STM32_MDMA_SET(n, mask)		((n) << STM32_MDMA_SHIFT(mask))
#define STM32_MDMA_GET(n, mask)		(((n) && mask) >> STM32_MDMA_SHIFT(mask))

Basically, u extract the shift using the mask value and ffs helping out, so
no need to define these and reduce chances of coding errors...

> +static int stm32_mdma_get_width(struct stm32_mdma_chan *chan,
> +				enum dma_slave_buswidth width)
> +{
> +	switch (width) {
> +	case DMA_SLAVE_BUSWIDTH_1_BYTE:
> +	case DMA_SLAVE_BUSWIDTH_2_BYTES:
> +	case DMA_SLAVE_BUSWIDTH_4_BYTES:
> +	case DMA_SLAVE_BUSWIDTH_8_BYTES:
> +		return ffs(width) - 1;
> +	default:
> +		dev_err(chan2dev(chan), "Dma bus width not supported\n");

please log the width here, helps in debug...

> +static u32 stm32_mdma_get_best_burst(u32 buf_len, u32 tlen, u32 max_burst,
> +				     enum dma_slave_buswidth width)
> +{
> +	u32 best_burst = max_burst;
> +	u32 burst_len = best_burst * width;
> +
> +	while ((burst_len > 0) && (tlen % burst_len)) {
> +		best_burst = best_burst >> 1;
> +		burst_len = best_burst * width;
> +	}
> +
> +	return (best_burst > 0) ? best_burst : 1;

when would best_burst <= 0? DO we really need this check


> +static struct dma_async_tx_descriptor *
> +stm32_mdma_prep_dma_cyclic(struct dma_chan *c, dma_addr_t buf_addr,
> +			   size_t buf_len, size_t period_len,
> +			   enum dma_transfer_direction direction,
> +			   unsigned long flags)
> +{
> +	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
> +	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
> +	struct dma_slave_config *dma_config = &chan->dma_config;
> +	struct stm32_mdma_desc *desc;
> +	dma_addr_t src_addr, dst_addr;
> +	u32 ccr, ctcr, ctbr, count;
> +	int i, ret;
> +
> +	if (!buf_len || !period_len || period_len > STM32_MDMA_MAX_BLOCK_LEN) {
> +		dev_err(chan2dev(chan), "Invalid buffer/period len\n");
> +		return NULL;
> +	}
> +
> +	if (buf_len % period_len) {
> +		dev_err(chan2dev(chan), "buf_len not multiple of period_len\n");
> +		return NULL;
> +	}
> +
> +	/*
> +	 * We allow to take more number of requests till DMA is
> +	 * not started. The driver will loop over all requests.
> +	 * Once DMA is started then new requests can be queued only after
> +	 * terminating the DMA.
> +	 */
> +	if (chan->busy) {
> +		dev_err(chan2dev(chan), "Request not allowed when dma busy\n");
> +		return NULL;
> +	}

is that a HW restriction? Once a txn is completed can't we submit
subsequent txn..? Can you explain this part please.

> +	if (len <= STM32_MDMA_MAX_BLOCK_LEN) {
> +		cbndtr |= STM32_MDMA_CBNDTR_BNDT(len);
> +		if (len <= STM32_MDMA_MAX_BUF_LEN) {
> +			/* Setup a buffer transfer */
> +			tlen = len;
> +			ccr |= STM32_MDMA_CCR_TCIE | STM32_MDMA_CCR_CTCIE;
> +			ctcr |= STM32_MDMA_CTCR_TRGM(STM32_MDMA_BUFFER);
> +			ctcr |= STM32_MDMA_CTCR_TLEN((tlen - 1));
> +		} else {
> +			/* Setup a block transfer */
> +			tlen = STM32_MDMA_MAX_BUF_LEN;
> +			ccr |= STM32_MDMA_CCR_BTIE | STM32_MDMA_CCR_CTCIE;
> +			ctcr |= STM32_MDMA_CTCR_TRGM(STM32_MDMA_BLOCK);
> +			ctcr |= STM32_MDMA_CTCR_TLEN(tlen - 1);
> +		}
> +
> +		/* Set best burst size */
> +		max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;

that maynot be best.. we should have wider and longer burst for best
throughput..

> +	ret = device_property_read_u32(&pdev->dev, "dma-requests",
> +				       &nr_requests);
> +	if (ret) {
> +		nr_requests = STM32_MDMA_MAX_REQUESTS;
> +		dev_warn(&pdev->dev, "MDMA defaulting on %i request lines\n",
> +			 nr_requests);
> +	}
> +
> +	count = of_property_count_u32_elems(of_node, "st,ahb-addr-masks");

We dont have device_property_xxx for this?

> +	if (count < 0)
> +		count = 0;
> +
> +	dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev) + sizeof(u32) * count,
> +			      GFP_KERNEL);
> +	if (!dmadev)
> +		return -ENOMEM;
> +
> +	dmadev->nr_channels = nr_channels;
> +	dmadev->nr_requests = nr_requests;
> +	of_property_read_u32_array(of_node, "st,ahb-addr-masks",
> +				   dmadev->ahb_addr_masks,
> +				   count);

i know we have an device api for array reads :)
and I think that helps in former case..

-- 
~Vinod

^ permalink raw reply	[flat|nested] 26+ messages in thread

* [PATCH v3 2/4] dmaengine: Add STM32 MDMA driver
@ 2017-08-16 16:47     ` Vinod Koul
  0 siblings, 0 replies; 26+ messages in thread
From: Vinod Koul @ 2017-08-16 16:47 UTC (permalink / raw)
  To: linux-arm-kernel

On Wed, Jul 26, 2017 at 11:48:20AM +0200, Pierre-Yves MORDRET wrote:

> +/* MDMA Channel x transfer configuration register */
> +#define STM32_MDMA_CTCR(x)		(0x50 + 0x40 * (x))
> +#define STM32_MDMA_CTCR_BWM		BIT(31)
> +#define STM32_MDMA_CTCR_SWRM		BIT(30)
> +#define STM32_MDMA_CTCR_TRGM_MSK	GENMASK(29, 28)
> +#define STM32_MDMA_CTCR_TRGM(n)		(((n) & 0x3) << 28)
> +#define STM32_MDMA_CTCR_TRGM_GET(n)	(((n) & STM32_MDMA_CTCR_TRGM_MSK) >> 28)

OK this seems oft repeated here.

So you are trying to extract the bit values and set the bit value, so why
not this do generically...

#define STM32_MDMA_SHIFT(n)		(ffs(n) - 1))
#define STM32_MDMA_SET(n, mask)		((n) << STM32_MDMA_SHIFT(mask))
#define STM32_MDMA_GET(n, mask)		(((n) && mask) >> STM32_MDMA_SHIFT(mask))

Basically, u extract the shift using the mask value and ffs helping out, so
no need to define these and reduce chances of coding errors...

> +static int stm32_mdma_get_width(struct stm32_mdma_chan *chan,
> +				enum dma_slave_buswidth width)
> +{
> +	switch (width) {
> +	case DMA_SLAVE_BUSWIDTH_1_BYTE:
> +	case DMA_SLAVE_BUSWIDTH_2_BYTES:
> +	case DMA_SLAVE_BUSWIDTH_4_BYTES:
> +	case DMA_SLAVE_BUSWIDTH_8_BYTES:
> +		return ffs(width) - 1;
> +	default:
> +		dev_err(chan2dev(chan), "Dma bus width not supported\n");

please log the width here, helps in debug...

> +static u32 stm32_mdma_get_best_burst(u32 buf_len, u32 tlen, u32 max_burst,
> +				     enum dma_slave_buswidth width)
> +{
> +	u32 best_burst = max_burst;
> +	u32 burst_len = best_burst * width;
> +
> +	while ((burst_len > 0) && (tlen % burst_len)) {
> +		best_burst = best_burst >> 1;
> +		burst_len = best_burst * width;
> +	}
> +
> +	return (best_burst > 0) ? best_burst : 1;

when would best_burst <= 0? DO we really need this check


> +static struct dma_async_tx_descriptor *
> +stm32_mdma_prep_dma_cyclic(struct dma_chan *c, dma_addr_t buf_addr,
> +			   size_t buf_len, size_t period_len,
> +			   enum dma_transfer_direction direction,
> +			   unsigned long flags)
> +{
> +	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
> +	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
> +	struct dma_slave_config *dma_config = &chan->dma_config;
> +	struct stm32_mdma_desc *desc;
> +	dma_addr_t src_addr, dst_addr;
> +	u32 ccr, ctcr, ctbr, count;
> +	int i, ret;
> +
> +	if (!buf_len || !period_len || period_len > STM32_MDMA_MAX_BLOCK_LEN) {
> +		dev_err(chan2dev(chan), "Invalid buffer/period len\n");
> +		return NULL;
> +	}
> +
> +	if (buf_len % period_len) {
> +		dev_err(chan2dev(chan), "buf_len not multiple of period_len\n");
> +		return NULL;
> +	}
> +
> +	/*
> +	 * We allow to take more number of requests till DMA is
> +	 * not started. The driver will loop over all requests.
> +	 * Once DMA is started then new requests can be queued only after
> +	 * terminating the DMA.
> +	 */
> +	if (chan->busy) {
> +		dev_err(chan2dev(chan), "Request not allowed when dma busy\n");
> +		return NULL;
> +	}

is that a HW restriction? Once a txn is completed can't we submit
subsequent txn..? Can you explain this part please.

> +	if (len <= STM32_MDMA_MAX_BLOCK_LEN) {
> +		cbndtr |= STM32_MDMA_CBNDTR_BNDT(len);
> +		if (len <= STM32_MDMA_MAX_BUF_LEN) {
> +			/* Setup a buffer transfer */
> +			tlen = len;
> +			ccr |= STM32_MDMA_CCR_TCIE | STM32_MDMA_CCR_CTCIE;
> +			ctcr |= STM32_MDMA_CTCR_TRGM(STM32_MDMA_BUFFER);
> +			ctcr |= STM32_MDMA_CTCR_TLEN((tlen - 1));
> +		} else {
> +			/* Setup a block transfer */
> +			tlen = STM32_MDMA_MAX_BUF_LEN;
> +			ccr |= STM32_MDMA_CCR_BTIE | STM32_MDMA_CCR_CTCIE;
> +			ctcr |= STM32_MDMA_CTCR_TRGM(STM32_MDMA_BLOCK);
> +			ctcr |= STM32_MDMA_CTCR_TLEN(tlen - 1);
> +		}
> +
> +		/* Set best burst size */
> +		max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;

that maynot be best.. we should have wider and longer burst for best
throughput..

> +	ret = device_property_read_u32(&pdev->dev, "dma-requests",
> +				       &nr_requests);
> +	if (ret) {
> +		nr_requests = STM32_MDMA_MAX_REQUESTS;
> +		dev_warn(&pdev->dev, "MDMA defaulting on %i request lines\n",
> +			 nr_requests);
> +	}
> +
> +	count = of_property_count_u32_elems(of_node, "st,ahb-addr-masks");

We dont have device_property_xxx for this?

> +	if (count < 0)
> +		count = 0;
> +
> +	dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev) + sizeof(u32) * count,
> +			      GFP_KERNEL);
> +	if (!dmadev)
> +		return -ENOMEM;
> +
> +	dmadev->nr_channels = nr_channels;
> +	dmadev->nr_requests = nr_requests;
> +	of_property_read_u32_array(of_node, "st,ahb-addr-masks",
> +				   dmadev->ahb_addr_masks,
> +				   count);

i know we have an device api for array reads :)
and I think that helps in former case..

-- 
~Vinod

^ permalink raw reply	[flat|nested] 26+ messages in thread

* Re: [PATCH v3 2/4] dmaengine: Add STM32 MDMA driver
  2017-08-16 16:47     ` Vinod Koul
  (?)
@ 2017-08-22 15:59       ` Pierre Yves MORDRET
  -1 siblings, 0 replies; 26+ messages in thread
From: Pierre Yves MORDRET @ 2017-08-22 15:59 UTC (permalink / raw)
  To: Vinod Koul
  Cc: Rob Herring, Mark Rutland, Maxime Coquelin, Alexandre Torgue,
	Russell King, Dan Williams, M'boumba Cedric Madianga,
	Fabrice GASNIER, Herbert Xu, Fabien DESSENNE, Amelie Delaunay,
	dmaengine, devicetree, linux-arm-kernel, linux-kernel



On 08/16/2017 06:47 PM, Vinod Koul wrote:
> On Wed, Jul 26, 2017 at 11:48:20AM +0200, Pierre-Yves MORDRET wrote:
> 
>> +/* MDMA Channel x transfer configuration register */
>> +#define STM32_MDMA_CTCR(x)		(0x50 + 0x40 * (x))
>> +#define STM32_MDMA_CTCR_BWM		BIT(31)
>> +#define STM32_MDMA_CTCR_SWRM		BIT(30)
>> +#define STM32_MDMA_CTCR_TRGM_MSK	GENMASK(29, 28)
>> +#define STM32_MDMA_CTCR_TRGM(n)		(((n) & 0x3) << 28)
>> +#define STM32_MDMA_CTCR_TRGM_GET(n)	(((n) & STM32_MDMA_CTCR_TRGM_MSK) >> 28)
> 
> OK this seems oft repeated here.
> 
> So you are trying to extract the bit values and set the bit value, so why
> not this do generically...
> 
> #define STM32_MDMA_SHIFT(n)		(ffs(n) - 1))
> #define STM32_MDMA_SET(n, mask)		((n) << STM32_MDMA_SHIFT(mask))
> #define STM32_MDMA_GET(n, mask)		(((n) && mask) >> STM32_MDMA_SHIFT(mask))
> 
> Basically, u extract the shift using the mask value and ffs helping out, so
> no need to define these and reduce chances of coding errors...
> 

OK.
but I would prefer if you don't mind
#define STM32_MDMA_SET(n, mask)		(((n) << STM32_MDMA_SHIFT(mask)) & mask)

>> +static int stm32_mdma_get_width(struct stm32_mdma_chan *chan,
>> +				enum dma_slave_buswidth width)
>> +{
>> +	switch (width) {
>> +	case DMA_SLAVE_BUSWIDTH_1_BYTE:
>> +	case DMA_SLAVE_BUSWIDTH_2_BYTES:
>> +	case DMA_SLAVE_BUSWIDTH_4_BYTES:
>> +	case DMA_SLAVE_BUSWIDTH_8_BYTES:
>> +		return ffs(width) - 1;
>> +	default:
>> +		dev_err(chan2dev(chan), "Dma bus width not supported\n");
> 
> please log the width here, helps in debug...
> 

Hum.. just a dev_dbg to log the actual width or within the dev_err ?

>> +static u32 stm32_mdma_get_best_burst(u32 buf_len, u32 tlen, u32 max_burst,
>> +				     enum dma_slave_buswidth width)
>> +{
>> +	u32 best_burst = max_burst;
>> +	u32 burst_len = best_burst * width;
>> +
>> +	while ((burst_len > 0) && (tlen % burst_len)) {
>> +		best_burst = best_burst >> 1;
>> +		burst_len = best_burst * width;
>> +	}
>> +
>> +	return (best_burst > 0) ? best_burst : 1;
> 
> when would best_burst <= 0? DO we really need this check
> 
> 

best_burst < 0 is obviously unlikely but =0 is likely whether no best burst
found. Se we do need this check.

>> +static struct dma_async_tx_descriptor *
>> +stm32_mdma_prep_dma_cyclic(struct dma_chan *c, dma_addr_t buf_addr,
>> +			   size_t buf_len, size_t period_len,
>> +			   enum dma_transfer_direction direction,
>> +			   unsigned long flags)
>> +{
>> +	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
>> +	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
>> +	struct dma_slave_config *dma_config = &chan->dma_config;
>> +	struct stm32_mdma_desc *desc;
>> +	dma_addr_t src_addr, dst_addr;
>> +	u32 ccr, ctcr, ctbr, count;
>> +	int i, ret;
>> +
>> +	if (!buf_len || !period_len || period_len > STM32_MDMA_MAX_BLOCK_LEN) {
>> +		dev_err(chan2dev(chan), "Invalid buffer/period len\n");
>> +		return NULL;
>> +	}
>> +
>> +	if (buf_len % period_len) {
>> +		dev_err(chan2dev(chan), "buf_len not multiple of period_len\n");
>> +		return NULL;
>> +	}
>> +
>> +	/*
>> +	 * We allow to take more number of requests till DMA is
>> +	 * not started. The driver will loop over all requests.
>> +	 * Once DMA is started then new requests can be queued only after
>> +	 * terminating the DMA.
>> +	 */
>> +	if (chan->busy) {
>> +		dev_err(chan2dev(chan), "Request not allowed when dma busy\n");
>> +		return NULL;
>> +	}
> 
> is that a HW restriction? Once a txn is completed can't we submit
> subsequent txn..? Can you explain this part please.
> 

Driver can prepare any request Slave SG, Memcpy or Cyclic. But if the channel is
busy to complete a DMA transfer, the request will be put in pending list. This
is only when the DMA transfer is going to be completed the next descriptor is
going to be processed and started.
However for cyclic this is different since when cyclic is ignited the channel
will be busy until its termination. This is why we forbid any DMA preparation
for this channel.
Nonetheless I believe we have a flaw here since we have to forbid
Slave/Memcpy/Cyclic whether a cyclic request is on-going.


>> +	if (len <= STM32_MDMA_MAX_BLOCK_LEN) {
>> +		cbndtr |= STM32_MDMA_CBNDTR_BNDT(len);
>> +		if (len <= STM32_MDMA_MAX_BUF_LEN) {
>> +			/* Setup a buffer transfer */
>> +			tlen = len;
>> +			ccr |= STM32_MDMA_CCR_TCIE | STM32_MDMA_CCR_CTCIE;
>> +			ctcr |= STM32_MDMA_CTCR_TRGM(STM32_MDMA_BUFFER);
>> +			ctcr |= STM32_MDMA_CTCR_TLEN((tlen - 1));
>> +		} else {
>> +			/* Setup a block transfer */
>> +			tlen = STM32_MDMA_MAX_BUF_LEN;
>> +			ccr |= STM32_MDMA_CCR_BTIE | STM32_MDMA_CCR_CTCIE;
>> +			ctcr |= STM32_MDMA_CTCR_TRGM(STM32_MDMA_BLOCK);
>> +			ctcr |= STM32_MDMA_CTCR_TLEN(tlen - 1);
>> +		}
>> +
>> +		/* Set best burst size */
>> +		max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
> 
> that maynot be best.. we should have wider and longer burst for best
> throughput..
> 

Will look at that.

>> +	ret = device_property_read_u32(&pdev->dev, "dma-requests",
>> +				       &nr_requests);
>> +	if (ret) {
>> +		nr_requests = STM32_MDMA_MAX_REQUESTS;
>> +		dev_warn(&pdev->dev, "MDMA defaulting on %i request lines\n",
>> +			 nr_requests);
>> +	}
>> +
>> +	count = of_property_count_u32_elems(of_node, "st,ahb-addr-masks");
> 
> We dont have device_property_xxx for this?

Sorry no. Well didn't figure out one though.

> 
>> +	if (count < 0)
>> +		count = 0;
>> +
>> +	dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev) + sizeof(u32) * count,
>> +			      GFP_KERNEL);
>> +	if (!dmadev)
>> +		return -ENOMEM;
>> +
>> +	dmadev->nr_channels = nr_channels;
>> +	dmadev->nr_requests = nr_requests;
>> +	of_property_read_u32_array(of_node, "st,ahb-addr-masks",
>> +				   dmadev->ahb_addr_masks,
>> +				   count);
> 
> i know we have an device api for array reads :)
> and I think that helps in former case..
> 

Correct :) device_property_read_u32_array

^ permalink raw reply	[flat|nested] 26+ messages in thread

* Re: [PATCH v3 2/4] dmaengine: Add STM32 MDMA driver
@ 2017-08-22 15:59       ` Pierre Yves MORDRET
  0 siblings, 0 replies; 26+ messages in thread
From: Pierre Yves MORDRET @ 2017-08-22 15:59 UTC (permalink / raw)
  To: Vinod Koul
  Cc: Mark Rutland, devicetree, Amelie Delaunay, Alexandre Torgue,
	Russell King, Fabien DESSENNE, linux-kernel, dmaengine,
	Rob Herring, Maxime Coquelin, M'boumba Cedric Madianga,
	Dan Williams, Fabrice GASNIER, linux-arm-kernel, Herbert Xu



On 08/16/2017 06:47 PM, Vinod Koul wrote:
> On Wed, Jul 26, 2017 at 11:48:20AM +0200, Pierre-Yves MORDRET wrote:
> 
>> +/* MDMA Channel x transfer configuration register */
>> +#define STM32_MDMA_CTCR(x)		(0x50 + 0x40 * (x))
>> +#define STM32_MDMA_CTCR_BWM		BIT(31)
>> +#define STM32_MDMA_CTCR_SWRM		BIT(30)
>> +#define STM32_MDMA_CTCR_TRGM_MSK	GENMASK(29, 28)
>> +#define STM32_MDMA_CTCR_TRGM(n)		(((n) & 0x3) << 28)
>> +#define STM32_MDMA_CTCR_TRGM_GET(n)	(((n) & STM32_MDMA_CTCR_TRGM_MSK) >> 28)
> 
> OK this seems oft repeated here.
> 
> So you are trying to extract the bit values and set the bit value, so why
> not this do generically...
> 
> #define STM32_MDMA_SHIFT(n)		(ffs(n) - 1))
> #define STM32_MDMA_SET(n, mask)		((n) << STM32_MDMA_SHIFT(mask))
> #define STM32_MDMA_GET(n, mask)		(((n) && mask) >> STM32_MDMA_SHIFT(mask))
> 
> Basically, u extract the shift using the mask value and ffs helping out, so
> no need to define these and reduce chances of coding errors...
> 

OK.
but I would prefer if you don't mind
#define STM32_MDMA_SET(n, mask)		(((n) << STM32_MDMA_SHIFT(mask)) & mask)

>> +static int stm32_mdma_get_width(struct stm32_mdma_chan *chan,
>> +				enum dma_slave_buswidth width)
>> +{
>> +	switch (width) {
>> +	case DMA_SLAVE_BUSWIDTH_1_BYTE:
>> +	case DMA_SLAVE_BUSWIDTH_2_BYTES:
>> +	case DMA_SLAVE_BUSWIDTH_4_BYTES:
>> +	case DMA_SLAVE_BUSWIDTH_8_BYTES:
>> +		return ffs(width) - 1;
>> +	default:
>> +		dev_err(chan2dev(chan), "Dma bus width not supported\n");
> 
> please log the width here, helps in debug...
> 

Hum.. just a dev_dbg to log the actual width or within the dev_err ?

>> +static u32 stm32_mdma_get_best_burst(u32 buf_len, u32 tlen, u32 max_burst,
>> +				     enum dma_slave_buswidth width)
>> +{
>> +	u32 best_burst = max_burst;
>> +	u32 burst_len = best_burst * width;
>> +
>> +	while ((burst_len > 0) && (tlen % burst_len)) {
>> +		best_burst = best_burst >> 1;
>> +		burst_len = best_burst * width;
>> +	}
>> +
>> +	return (best_burst > 0) ? best_burst : 1;
> 
> when would best_burst <= 0? DO we really need this check
> 
> 

best_burst < 0 is obviously unlikely but =0 is likely whether no best burst
found. Se we do need this check.

>> +static struct dma_async_tx_descriptor *
>> +stm32_mdma_prep_dma_cyclic(struct dma_chan *c, dma_addr_t buf_addr,
>> +			   size_t buf_len, size_t period_len,
>> +			   enum dma_transfer_direction direction,
>> +			   unsigned long flags)
>> +{
>> +	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
>> +	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
>> +	struct dma_slave_config *dma_config = &chan->dma_config;
>> +	struct stm32_mdma_desc *desc;
>> +	dma_addr_t src_addr, dst_addr;
>> +	u32 ccr, ctcr, ctbr, count;
>> +	int i, ret;
>> +
>> +	if (!buf_len || !period_len || period_len > STM32_MDMA_MAX_BLOCK_LEN) {
>> +		dev_err(chan2dev(chan), "Invalid buffer/period len\n");
>> +		return NULL;
>> +	}
>> +
>> +	if (buf_len % period_len) {
>> +		dev_err(chan2dev(chan), "buf_len not multiple of period_len\n");
>> +		return NULL;
>> +	}
>> +
>> +	/*
>> +	 * We allow to take more number of requests till DMA is
>> +	 * not started. The driver will loop over all requests.
>> +	 * Once DMA is started then new requests can be queued only after
>> +	 * terminating the DMA.
>> +	 */
>> +	if (chan->busy) {
>> +		dev_err(chan2dev(chan), "Request not allowed when dma busy\n");
>> +		return NULL;
>> +	}
> 
> is that a HW restriction? Once a txn is completed can't we submit
> subsequent txn..? Can you explain this part please.
> 

Driver can prepare any request Slave SG, Memcpy or Cyclic. But if the channel is
busy to complete a DMA transfer, the request will be put in pending list. This
is only when the DMA transfer is going to be completed the next descriptor is
going to be processed and started.
However for cyclic this is different since when cyclic is ignited the channel
will be busy until its termination. This is why we forbid any DMA preparation
for this channel.
Nonetheless I believe we have a flaw here since we have to forbid
Slave/Memcpy/Cyclic whether a cyclic request is on-going.


>> +	if (len <= STM32_MDMA_MAX_BLOCK_LEN) {
>> +		cbndtr |= STM32_MDMA_CBNDTR_BNDT(len);
>> +		if (len <= STM32_MDMA_MAX_BUF_LEN) {
>> +			/* Setup a buffer transfer */
>> +			tlen = len;
>> +			ccr |= STM32_MDMA_CCR_TCIE | STM32_MDMA_CCR_CTCIE;
>> +			ctcr |= STM32_MDMA_CTCR_TRGM(STM32_MDMA_BUFFER);
>> +			ctcr |= STM32_MDMA_CTCR_TLEN((tlen - 1));
>> +		} else {
>> +			/* Setup a block transfer */
>> +			tlen = STM32_MDMA_MAX_BUF_LEN;
>> +			ccr |= STM32_MDMA_CCR_BTIE | STM32_MDMA_CCR_CTCIE;
>> +			ctcr |= STM32_MDMA_CTCR_TRGM(STM32_MDMA_BLOCK);
>> +			ctcr |= STM32_MDMA_CTCR_TLEN(tlen - 1);
>> +		}
>> +
>> +		/* Set best burst size */
>> +		max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
> 
> that maynot be best.. we should have wider and longer burst for best
> throughput..
> 

Will look at that.

>> +	ret = device_property_read_u32(&pdev->dev, "dma-requests",
>> +				       &nr_requests);
>> +	if (ret) {
>> +		nr_requests = STM32_MDMA_MAX_REQUESTS;
>> +		dev_warn(&pdev->dev, "MDMA defaulting on %i request lines\n",
>> +			 nr_requests);
>> +	}
>> +
>> +	count = of_property_count_u32_elems(of_node, "st,ahb-addr-masks");
> 
> We dont have device_property_xxx for this?

Sorry no. Well didn't figure out one though.

> 
>> +	if (count < 0)
>> +		count = 0;
>> +
>> +	dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev) + sizeof(u32) * count,
>> +			      GFP_KERNEL);
>> +	if (!dmadev)
>> +		return -ENOMEM;
>> +
>> +	dmadev->nr_channels = nr_channels;
>> +	dmadev->nr_requests = nr_requests;
>> +	of_property_read_u32_array(of_node, "st,ahb-addr-masks",
>> +				   dmadev->ahb_addr_masks,
>> +				   count);
> 
> i know we have an device api for array reads :)
> and I think that helps in former case..
> 

Correct :) device_property_read_u32_array

^ permalink raw reply	[flat|nested] 26+ messages in thread

* [PATCH v3 2/4] dmaengine: Add STM32 MDMA driver
@ 2017-08-22 15:59       ` Pierre Yves MORDRET
  0 siblings, 0 replies; 26+ messages in thread
From: Pierre Yves MORDRET @ 2017-08-22 15:59 UTC (permalink / raw)
  To: linux-arm-kernel



On 08/16/2017 06:47 PM, Vinod Koul wrote:
> On Wed, Jul 26, 2017 at 11:48:20AM +0200, Pierre-Yves MORDRET wrote:
> 
>> +/* MDMA Channel x transfer configuration register */
>> +#define STM32_MDMA_CTCR(x)		(0x50 + 0x40 * (x))
>> +#define STM32_MDMA_CTCR_BWM		BIT(31)
>> +#define STM32_MDMA_CTCR_SWRM		BIT(30)
>> +#define STM32_MDMA_CTCR_TRGM_MSK	GENMASK(29, 28)
>> +#define STM32_MDMA_CTCR_TRGM(n)		(((n) & 0x3) << 28)
>> +#define STM32_MDMA_CTCR_TRGM_GET(n)	(((n) & STM32_MDMA_CTCR_TRGM_MSK) >> 28)
> 
> OK this seems oft repeated here.
> 
> So you are trying to extract the bit values and set the bit value, so why
> not this do generically...
> 
> #define STM32_MDMA_SHIFT(n)		(ffs(n) - 1))
> #define STM32_MDMA_SET(n, mask)		((n) << STM32_MDMA_SHIFT(mask))
> #define STM32_MDMA_GET(n, mask)		(((n) && mask) >> STM32_MDMA_SHIFT(mask))
> 
> Basically, u extract the shift using the mask value and ffs helping out, so
> no need to define these and reduce chances of coding errors...
> 

OK.
but I would prefer if you don't mind
#define STM32_MDMA_SET(n, mask)		(((n) << STM32_MDMA_SHIFT(mask)) & mask)

>> +static int stm32_mdma_get_width(struct stm32_mdma_chan *chan,
>> +				enum dma_slave_buswidth width)
>> +{
>> +	switch (width) {
>> +	case DMA_SLAVE_BUSWIDTH_1_BYTE:
>> +	case DMA_SLAVE_BUSWIDTH_2_BYTES:
>> +	case DMA_SLAVE_BUSWIDTH_4_BYTES:
>> +	case DMA_SLAVE_BUSWIDTH_8_BYTES:
>> +		return ffs(width) - 1;
>> +	default:
>> +		dev_err(chan2dev(chan), "Dma bus width not supported\n");
> 
> please log the width here, helps in debug...
> 

Hum.. just a dev_dbg to log the actual width or within the dev_err ?

>> +static u32 stm32_mdma_get_best_burst(u32 buf_len, u32 tlen, u32 max_burst,
>> +				     enum dma_slave_buswidth width)
>> +{
>> +	u32 best_burst = max_burst;
>> +	u32 burst_len = best_burst * width;
>> +
>> +	while ((burst_len > 0) && (tlen % burst_len)) {
>> +		best_burst = best_burst >> 1;
>> +		burst_len = best_burst * width;
>> +	}
>> +
>> +	return (best_burst > 0) ? best_burst : 1;
> 
> when would best_burst <= 0? DO we really need this check
> 
> 

best_burst < 0 is obviously unlikely but =0 is likely whether no best burst
found. Se we do need this check.

>> +static struct dma_async_tx_descriptor *
>> +stm32_mdma_prep_dma_cyclic(struct dma_chan *c, dma_addr_t buf_addr,
>> +			   size_t buf_len, size_t period_len,
>> +			   enum dma_transfer_direction direction,
>> +			   unsigned long flags)
>> +{
>> +	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
>> +	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
>> +	struct dma_slave_config *dma_config = &chan->dma_config;
>> +	struct stm32_mdma_desc *desc;
>> +	dma_addr_t src_addr, dst_addr;
>> +	u32 ccr, ctcr, ctbr, count;
>> +	int i, ret;
>> +
>> +	if (!buf_len || !period_len || period_len > STM32_MDMA_MAX_BLOCK_LEN) {
>> +		dev_err(chan2dev(chan), "Invalid buffer/period len\n");
>> +		return NULL;
>> +	}
>> +
>> +	if (buf_len % period_len) {
>> +		dev_err(chan2dev(chan), "buf_len not multiple of period_len\n");
>> +		return NULL;
>> +	}
>> +
>> +	/*
>> +	 * We allow to take more number of requests till DMA is
>> +	 * not started. The driver will loop over all requests.
>> +	 * Once DMA is started then new requests can be queued only after
>> +	 * terminating the DMA.
>> +	 */
>> +	if (chan->busy) {
>> +		dev_err(chan2dev(chan), "Request not allowed when dma busy\n");
>> +		return NULL;
>> +	}
> 
> is that a HW restriction? Once a txn is completed can't we submit
> subsequent txn..? Can you explain this part please.
> 

Driver can prepare any request Slave SG, Memcpy or Cyclic. But if the channel is
busy to complete a DMA transfer, the request will be put in pending list. This
is only when the DMA transfer is going to be completed the next descriptor is
going to be processed and started.
However for cyclic this is different since when cyclic is ignited the channel
will be busy until its termination. This is why we forbid any DMA preparation
for this channel.
Nonetheless I believe we have a flaw here since we have to forbid
Slave/Memcpy/Cyclic whether a cyclic request is on-going.


>> +	if (len <= STM32_MDMA_MAX_BLOCK_LEN) {
>> +		cbndtr |= STM32_MDMA_CBNDTR_BNDT(len);
>> +		if (len <= STM32_MDMA_MAX_BUF_LEN) {
>> +			/* Setup a buffer transfer */
>> +			tlen = len;
>> +			ccr |= STM32_MDMA_CCR_TCIE | STM32_MDMA_CCR_CTCIE;
>> +			ctcr |= STM32_MDMA_CTCR_TRGM(STM32_MDMA_BUFFER);
>> +			ctcr |= STM32_MDMA_CTCR_TLEN((tlen - 1));
>> +		} else {
>> +			/* Setup a block transfer */
>> +			tlen = STM32_MDMA_MAX_BUF_LEN;
>> +			ccr |= STM32_MDMA_CCR_BTIE | STM32_MDMA_CCR_CTCIE;
>> +			ctcr |= STM32_MDMA_CTCR_TRGM(STM32_MDMA_BLOCK);
>> +			ctcr |= STM32_MDMA_CTCR_TLEN(tlen - 1);
>> +		}
>> +
>> +		/* Set best burst size */
>> +		max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
> 
> that maynot be best.. we should have wider and longer burst for best
> throughput..
> 

Will look at that.

>> +	ret = device_property_read_u32(&pdev->dev, "dma-requests",
>> +				       &nr_requests);
>> +	if (ret) {
>> +		nr_requests = STM32_MDMA_MAX_REQUESTS;
>> +		dev_warn(&pdev->dev, "MDMA defaulting on %i request lines\n",
>> +			 nr_requests);
>> +	}
>> +
>> +	count = of_property_count_u32_elems(of_node, "st,ahb-addr-masks");
> 
> We dont have device_property_xxx for this?

Sorry no. Well didn't figure out one though.

> 
>> +	if (count < 0)
>> +		count = 0;
>> +
>> +	dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev) + sizeof(u32) * count,
>> +			      GFP_KERNEL);
>> +	if (!dmadev)
>> +		return -ENOMEM;
>> +
>> +	dmadev->nr_channels = nr_channels;
>> +	dmadev->nr_requests = nr_requests;
>> +	of_property_read_u32_array(of_node, "st,ahb-addr-masks",
>> +				   dmadev->ahb_addr_masks,
>> +				   count);
> 
> i know we have an device api for array reads :)
> and I think that helps in former case..
> 

Correct :) device_property_read_u32_array

^ permalink raw reply	[flat|nested] 26+ messages in thread

* Re: [PATCH v3 2/4] dmaengine: Add STM32 MDMA driver
@ 2017-08-23 16:00         ` Vinod Koul
  0 siblings, 0 replies; 26+ messages in thread
From: Vinod Koul @ 2017-08-23 16:00 UTC (permalink / raw)
  To: Pierre Yves MORDRET
  Cc: Rob Herring, Mark Rutland, Maxime Coquelin, Alexandre Torgue,
	Russell King, Dan Williams, M'boumba Cedric Madianga,
	Fabrice GASNIER, Herbert Xu, Fabien DESSENNE, Amelie Delaunay,
	dmaengine, devicetree, linux-arm-kernel, linux-kernel

On Tue, Aug 22, 2017 at 05:59:26PM +0200, Pierre Yves MORDRET wrote:
> 
> 
> On 08/16/2017 06:47 PM, Vinod Koul wrote:
> > On Wed, Jul 26, 2017 at 11:48:20AM +0200, Pierre-Yves MORDRET wrote:
> > 
> >> +/* MDMA Channel x transfer configuration register */
> >> +#define STM32_MDMA_CTCR(x)		(0x50 + 0x40 * (x))
> >> +#define STM32_MDMA_CTCR_BWM		BIT(31)
> >> +#define STM32_MDMA_CTCR_SWRM		BIT(30)
> >> +#define STM32_MDMA_CTCR_TRGM_MSK	GENMASK(29, 28)
> >> +#define STM32_MDMA_CTCR_TRGM(n)		(((n) & 0x3) << 28)
> >> +#define STM32_MDMA_CTCR_TRGM_GET(n)	(((n) & STM32_MDMA_CTCR_TRGM_MSK) >> 28)
> > 
> > OK this seems oft repeated here.
> > 
> > So you are trying to extract the bit values and set the bit value, so why
> > not this do generically...
> > 
> > #define STM32_MDMA_SHIFT(n)		(ffs(n) - 1))
> > #define STM32_MDMA_SET(n, mask)		((n) << STM32_MDMA_SHIFT(mask))
> > #define STM32_MDMA_GET(n, mask)		(((n) && mask) >> STM32_MDMA_SHIFT(mask))
> > 
> > Basically, u extract the shift using the mask value and ffs helping out, so
> > no need to define these and reduce chances of coding errors...
> > 
> 
> OK.
> but I would prefer if you don't mind

hmmm, I don't have a very strong opinion, so okay. But from programming PoV
it reduces human errors..

> #define STM32_MDMA_SET(n, mask)		(((n) << STM32_MDMA_SHIFT(mask)) & mask)
> 
> >> +static int stm32_mdma_get_width(struct stm32_mdma_chan *chan,
> >> +				enum dma_slave_buswidth width)
> >> +{
> >> +	switch (width) {
> >> +	case DMA_SLAVE_BUSWIDTH_1_BYTE:
> >> +	case DMA_SLAVE_BUSWIDTH_2_BYTES:
> >> +	case DMA_SLAVE_BUSWIDTH_4_BYTES:
> >> +	case DMA_SLAVE_BUSWIDTH_8_BYTES:
> >> +		return ffs(width) - 1;
> >> +	default:
> >> +		dev_err(chan2dev(chan), "Dma bus width not supported\n");
> > 
> > please log the width here, helps in debug...
> > 
> 
> Hum.. just a dev_dbg to log the actual width or within the dev_err ?

latter pls

> 
> >> +static u32 stm32_mdma_get_best_burst(u32 buf_len, u32 tlen, u32 max_burst,
> >> +				     enum dma_slave_buswidth width)
> >> +{
> >> +	u32 best_burst = max_burst;
> >> +	u32 burst_len = best_burst * width;
> >> +
> >> +	while ((burst_len > 0) && (tlen % burst_len)) {
> >> +		best_burst = best_burst >> 1;
> >> +		burst_len = best_burst * width;
> >> +	}
> >> +
> >> +	return (best_burst > 0) ? best_burst : 1;
> > 
> > when would best_burst <= 0? DO we really need this check
> > 
> > 
> 
> best_burst < 0 is obviously unlikely but =0 is likely whether no best burst
> found. Se we do need this check.
> 
> >> +static struct dma_async_tx_descriptor *
> >> +stm32_mdma_prep_dma_cyclic(struct dma_chan *c, dma_addr_t buf_addr,
> >> +			   size_t buf_len, size_t period_len,
> >> +			   enum dma_transfer_direction direction,
> >> +			   unsigned long flags)
> >> +{
> >> +	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
> >> +	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
> >> +	struct dma_slave_config *dma_config = &chan->dma_config;
> >> +	struct stm32_mdma_desc *desc;
> >> +	dma_addr_t src_addr, dst_addr;
> >> +	u32 ccr, ctcr, ctbr, count;
> >> +	int i, ret;
> >> +
> >> +	if (!buf_len || !period_len || period_len > STM32_MDMA_MAX_BLOCK_LEN) {
> >> +		dev_err(chan2dev(chan), "Invalid buffer/period len\n");
> >> +		return NULL;
> >> +	}
> >> +
> >> +	if (buf_len % period_len) {
> >> +		dev_err(chan2dev(chan), "buf_len not multiple of period_len\n");
> >> +		return NULL;
> >> +	}
> >> +
> >> +	/*
> >> +	 * We allow to take more number of requests till DMA is
> >> +	 * not started. The driver will loop over all requests.
> >> +	 * Once DMA is started then new requests can be queued only after
> >> +	 * terminating the DMA.
> >> +	 */
> >> +	if (chan->busy) {
> >> +		dev_err(chan2dev(chan), "Request not allowed when dma busy\n");
> >> +		return NULL;
> >> +	}
> > 
> > is that a HW restriction? Once a txn is completed can't we submit
> > subsequent txn..? Can you explain this part please.
> > 
> 
> Driver can prepare any request Slave SG, Memcpy or Cyclic. But if the channel is
> busy to complete a DMA transfer, the request will be put in pending list. This
> is only when the DMA transfer is going to be completed the next descriptor is
> going to be processed and started.
> However for cyclic this is different since when cyclic is ignited the channel
> will be busy until its termination. This is why we forbid any DMA preparation
> for this channel.
> Nonetheless I believe we have a flaw here since we have to forbid
> Slave/Memcpy/Cyclic whether a cyclic request is on-going.

But you are not submitting a txn to HW. The prepare_xxx operation prepares a
descriptor which is pushed to pending queue on submit and further pushed to
hw on queue move or issue_pending()

So here we should ideally accept the request.

After you finish memcpy you can submit a memcpy right...?

> 
> 
> >> +	if (len <= STM32_MDMA_MAX_BLOCK_LEN) {
> >> +		cbndtr |= STM32_MDMA_CBNDTR_BNDT(len);
> >> +		if (len <= STM32_MDMA_MAX_BUF_LEN) {
> >> +			/* Setup a buffer transfer */
> >> +			tlen = len;
> >> +			ccr |= STM32_MDMA_CCR_TCIE | STM32_MDMA_CCR_CTCIE;
> >> +			ctcr |= STM32_MDMA_CTCR_TRGM(STM32_MDMA_BUFFER);
> >> +			ctcr |= STM32_MDMA_CTCR_TLEN((tlen - 1));
> >> +		} else {
> >> +			/* Setup a block transfer */
> >> +			tlen = STM32_MDMA_MAX_BUF_LEN;
> >> +			ccr |= STM32_MDMA_CCR_BTIE | STM32_MDMA_CCR_CTCIE;
> >> +			ctcr |= STM32_MDMA_CTCR_TRGM(STM32_MDMA_BLOCK);
> >> +			ctcr |= STM32_MDMA_CTCR_TLEN(tlen - 1);
> >> +		}
> >> +
> >> +		/* Set best burst size */
> >> +		max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
> > 
> > that maynot be best.. we should have wider and longer burst for best
> > throughput..
> > 
> 
> Will look at that.
> 
> >> +	ret = device_property_read_u32(&pdev->dev, "dma-requests",
> >> +				       &nr_requests);
> >> +	if (ret) {
> >> +		nr_requests = STM32_MDMA_MAX_REQUESTS;
> >> +		dev_warn(&pdev->dev, "MDMA defaulting on %i request lines\n",
> >> +			 nr_requests);
> >> +	}
> >> +
> >> +	count = of_property_count_u32_elems(of_node, "st,ahb-addr-masks");
> > 
> > We dont have device_property_xxx for this?
> 
> Sorry no. Well didn't figure out one though.

we do :) the array property with NULL argument returns the size of array..

int device_property_read_u32_array(struct device *dev, const char *propname,
				   u32 *val, size_t nval)

Documentation says:
 Return: number of values if @val was %NULL,

> 
> > 
> >> +	if (count < 0)
> >> +		count = 0;
> >> +
> >> +	dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev) + sizeof(u32) * count,
> >> +			      GFP_KERNEL);
> >> +	if (!dmadev)
> >> +		return -ENOMEM;
> >> +
> >> +	dmadev->nr_channels = nr_channels;
> >> +	dmadev->nr_requests = nr_requests;
> >> +	of_property_read_u32_array(of_node, "st,ahb-addr-masks",
> >> +				   dmadev->ahb_addr_masks,
> >> +				   count);
> > 
> > i know we have an device api for array reads :)
> > and I think that helps in former case..
> > 
> 
> Correct :) device_property_read_u32_array

yes..

-- 
~Vinod

^ permalink raw reply	[flat|nested] 26+ messages in thread

* Re: [PATCH v3 2/4] dmaengine: Add STM32 MDMA driver
@ 2017-08-23 16:00         ` Vinod Koul
  0 siblings, 0 replies; 26+ messages in thread
From: Vinod Koul @ 2017-08-23 16:00 UTC (permalink / raw)
  To: Pierre Yves MORDRET
  Cc: Rob Herring, Mark Rutland, Maxime Coquelin, Alexandre Torgue,
	Russell King, Dan Williams, M'boumba Cedric Madianga,
	Fabrice GASNIER, Herbert Xu, Fabien DESSENNE, Amelie Delaunay,
	dmaengine-u79uwXL29TY76Z2rM5mHXA,
	devicetree-u79uwXL29TY76Z2rM5mHXA,
	linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA

On Tue, Aug 22, 2017 at 05:59:26PM +0200, Pierre Yves MORDRET wrote:
> 
> 
> On 08/16/2017 06:47 PM, Vinod Koul wrote:
> > On Wed, Jul 26, 2017 at 11:48:20AM +0200, Pierre-Yves MORDRET wrote:
> > 
> >> +/* MDMA Channel x transfer configuration register */
> >> +#define STM32_MDMA_CTCR(x)		(0x50 + 0x40 * (x))
> >> +#define STM32_MDMA_CTCR_BWM		BIT(31)
> >> +#define STM32_MDMA_CTCR_SWRM		BIT(30)
> >> +#define STM32_MDMA_CTCR_TRGM_MSK	GENMASK(29, 28)
> >> +#define STM32_MDMA_CTCR_TRGM(n)		(((n) & 0x3) << 28)
> >> +#define STM32_MDMA_CTCR_TRGM_GET(n)	(((n) & STM32_MDMA_CTCR_TRGM_MSK) >> 28)
> > 
> > OK this seems oft repeated here.
> > 
> > So you are trying to extract the bit values and set the bit value, so why
> > not this do generically...
> > 
> > #define STM32_MDMA_SHIFT(n)		(ffs(n) - 1))
> > #define STM32_MDMA_SET(n, mask)		((n) << STM32_MDMA_SHIFT(mask))
> > #define STM32_MDMA_GET(n, mask)		(((n) && mask) >> STM32_MDMA_SHIFT(mask))
> > 
> > Basically, u extract the shift using the mask value and ffs helping out, so
> > no need to define these and reduce chances of coding errors...
> > 
> 
> OK.
> but I would prefer if you don't mind

hmmm, I don't have a very strong opinion, so okay. But from programming PoV
it reduces human errors..

> #define STM32_MDMA_SET(n, mask)		(((n) << STM32_MDMA_SHIFT(mask)) & mask)
> 
> >> +static int stm32_mdma_get_width(struct stm32_mdma_chan *chan,
> >> +				enum dma_slave_buswidth width)
> >> +{
> >> +	switch (width) {
> >> +	case DMA_SLAVE_BUSWIDTH_1_BYTE:
> >> +	case DMA_SLAVE_BUSWIDTH_2_BYTES:
> >> +	case DMA_SLAVE_BUSWIDTH_4_BYTES:
> >> +	case DMA_SLAVE_BUSWIDTH_8_BYTES:
> >> +		return ffs(width) - 1;
> >> +	default:
> >> +		dev_err(chan2dev(chan), "Dma bus width not supported\n");
> > 
> > please log the width here, helps in debug...
> > 
> 
> Hum.. just a dev_dbg to log the actual width or within the dev_err ?

latter pls

> 
> >> +static u32 stm32_mdma_get_best_burst(u32 buf_len, u32 tlen, u32 max_burst,
> >> +				     enum dma_slave_buswidth width)
> >> +{
> >> +	u32 best_burst = max_burst;
> >> +	u32 burst_len = best_burst * width;
> >> +
> >> +	while ((burst_len > 0) && (tlen % burst_len)) {
> >> +		best_burst = best_burst >> 1;
> >> +		burst_len = best_burst * width;
> >> +	}
> >> +
> >> +	return (best_burst > 0) ? best_burst : 1;
> > 
> > when would best_burst <= 0? DO we really need this check
> > 
> > 
> 
> best_burst < 0 is obviously unlikely but =0 is likely whether no best burst
> found. Se we do need this check.
> 
> >> +static struct dma_async_tx_descriptor *
> >> +stm32_mdma_prep_dma_cyclic(struct dma_chan *c, dma_addr_t buf_addr,
> >> +			   size_t buf_len, size_t period_len,
> >> +			   enum dma_transfer_direction direction,
> >> +			   unsigned long flags)
> >> +{
> >> +	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
> >> +	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
> >> +	struct dma_slave_config *dma_config = &chan->dma_config;
> >> +	struct stm32_mdma_desc *desc;
> >> +	dma_addr_t src_addr, dst_addr;
> >> +	u32 ccr, ctcr, ctbr, count;
> >> +	int i, ret;
> >> +
> >> +	if (!buf_len || !period_len || period_len > STM32_MDMA_MAX_BLOCK_LEN) {
> >> +		dev_err(chan2dev(chan), "Invalid buffer/period len\n");
> >> +		return NULL;
> >> +	}
> >> +
> >> +	if (buf_len % period_len) {
> >> +		dev_err(chan2dev(chan), "buf_len not multiple of period_len\n");
> >> +		return NULL;
> >> +	}
> >> +
> >> +	/*
> >> +	 * We allow to take more number of requests till DMA is
> >> +	 * not started. The driver will loop over all requests.
> >> +	 * Once DMA is started then new requests can be queued only after
> >> +	 * terminating the DMA.
> >> +	 */
> >> +	if (chan->busy) {
> >> +		dev_err(chan2dev(chan), "Request not allowed when dma busy\n");
> >> +		return NULL;
> >> +	}
> > 
> > is that a HW restriction? Once a txn is completed can't we submit
> > subsequent txn..? Can you explain this part please.
> > 
> 
> Driver can prepare any request Slave SG, Memcpy or Cyclic. But if the channel is
> busy to complete a DMA transfer, the request will be put in pending list. This
> is only when the DMA transfer is going to be completed the next descriptor is
> going to be processed and started.
> However for cyclic this is different since when cyclic is ignited the channel
> will be busy until its termination. This is why we forbid any DMA preparation
> for this channel.
> Nonetheless I believe we have a flaw here since we have to forbid
> Slave/Memcpy/Cyclic whether a cyclic request is on-going.

But you are not submitting a txn to HW. The prepare_xxx operation prepares a
descriptor which is pushed to pending queue on submit and further pushed to
hw on queue move or issue_pending()

So here we should ideally accept the request.

After you finish memcpy you can submit a memcpy right...?

> 
> 
> >> +	if (len <= STM32_MDMA_MAX_BLOCK_LEN) {
> >> +		cbndtr |= STM32_MDMA_CBNDTR_BNDT(len);
> >> +		if (len <= STM32_MDMA_MAX_BUF_LEN) {
> >> +			/* Setup a buffer transfer */
> >> +			tlen = len;
> >> +			ccr |= STM32_MDMA_CCR_TCIE | STM32_MDMA_CCR_CTCIE;
> >> +			ctcr |= STM32_MDMA_CTCR_TRGM(STM32_MDMA_BUFFER);
> >> +			ctcr |= STM32_MDMA_CTCR_TLEN((tlen - 1));
> >> +		} else {
> >> +			/* Setup a block transfer */
> >> +			tlen = STM32_MDMA_MAX_BUF_LEN;
> >> +			ccr |= STM32_MDMA_CCR_BTIE | STM32_MDMA_CCR_CTCIE;
> >> +			ctcr |= STM32_MDMA_CTCR_TRGM(STM32_MDMA_BLOCK);
> >> +			ctcr |= STM32_MDMA_CTCR_TLEN(tlen - 1);
> >> +		}
> >> +
> >> +		/* Set best burst size */
> >> +		max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
> > 
> > that maynot be best.. we should have wider and longer burst for best
> > throughput..
> > 
> 
> Will look at that.
> 
> >> +	ret = device_property_read_u32(&pdev->dev, "dma-requests",
> >> +				       &nr_requests);
> >> +	if (ret) {
> >> +		nr_requests = STM32_MDMA_MAX_REQUESTS;
> >> +		dev_warn(&pdev->dev, "MDMA defaulting on %i request lines\n",
> >> +			 nr_requests);
> >> +	}
> >> +
> >> +	count = of_property_count_u32_elems(of_node, "st,ahb-addr-masks");
> > 
> > We dont have device_property_xxx for this?
> 
> Sorry no. Well didn't figure out one though.

we do :) the array property with NULL argument returns the size of array..

int device_property_read_u32_array(struct device *dev, const char *propname,
				   u32 *val, size_t nval)

Documentation says:
 Return: number of values if @val was %NULL,

> 
> > 
> >> +	if (count < 0)
> >> +		count = 0;
> >> +
> >> +	dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev) + sizeof(u32) * count,
> >> +			      GFP_KERNEL);
> >> +	if (!dmadev)
> >> +		return -ENOMEM;
> >> +
> >> +	dmadev->nr_channels = nr_channels;
> >> +	dmadev->nr_requests = nr_requests;
> >> +	of_property_read_u32_array(of_node, "st,ahb-addr-masks",
> >> +				   dmadev->ahb_addr_masks,
> >> +				   count);
> > 
> > i know we have an device api for array reads :)
> > and I think that helps in former case..
> > 
> 
> Correct :) device_property_read_u32_array

yes..

-- 
~Vinod
--
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^ permalink raw reply	[flat|nested] 26+ messages in thread

* [PATCH v3 2/4] dmaengine: Add STM32 MDMA driver
@ 2017-08-23 16:00         ` Vinod Koul
  0 siblings, 0 replies; 26+ messages in thread
From: Vinod Koul @ 2017-08-23 16:00 UTC (permalink / raw)
  To: linux-arm-kernel

On Tue, Aug 22, 2017 at 05:59:26PM +0200, Pierre Yves MORDRET wrote:
> 
> 
> On 08/16/2017 06:47 PM, Vinod Koul wrote:
> > On Wed, Jul 26, 2017 at 11:48:20AM +0200, Pierre-Yves MORDRET wrote:
> > 
> >> +/* MDMA Channel x transfer configuration register */
> >> +#define STM32_MDMA_CTCR(x)		(0x50 + 0x40 * (x))
> >> +#define STM32_MDMA_CTCR_BWM		BIT(31)
> >> +#define STM32_MDMA_CTCR_SWRM		BIT(30)
> >> +#define STM32_MDMA_CTCR_TRGM_MSK	GENMASK(29, 28)
> >> +#define STM32_MDMA_CTCR_TRGM(n)		(((n) & 0x3) << 28)
> >> +#define STM32_MDMA_CTCR_TRGM_GET(n)	(((n) & STM32_MDMA_CTCR_TRGM_MSK) >> 28)
> > 
> > OK this seems oft repeated here.
> > 
> > So you are trying to extract the bit values and set the bit value, so why
> > not this do generically...
> > 
> > #define STM32_MDMA_SHIFT(n)		(ffs(n) - 1))
> > #define STM32_MDMA_SET(n, mask)		((n) << STM32_MDMA_SHIFT(mask))
> > #define STM32_MDMA_GET(n, mask)		(((n) && mask) >> STM32_MDMA_SHIFT(mask))
> > 
> > Basically, u extract the shift using the mask value and ffs helping out, so
> > no need to define these and reduce chances of coding errors...
> > 
> 
> OK.
> but I would prefer if you don't mind

hmmm, I don't have a very strong opinion, so okay. But from programming PoV
it reduces human errors..

> #define STM32_MDMA_SET(n, mask)		(((n) << STM32_MDMA_SHIFT(mask)) & mask)
> 
> >> +static int stm32_mdma_get_width(struct stm32_mdma_chan *chan,
> >> +				enum dma_slave_buswidth width)
> >> +{
> >> +	switch (width) {
> >> +	case DMA_SLAVE_BUSWIDTH_1_BYTE:
> >> +	case DMA_SLAVE_BUSWIDTH_2_BYTES:
> >> +	case DMA_SLAVE_BUSWIDTH_4_BYTES:
> >> +	case DMA_SLAVE_BUSWIDTH_8_BYTES:
> >> +		return ffs(width) - 1;
> >> +	default:
> >> +		dev_err(chan2dev(chan), "Dma bus width not supported\n");
> > 
> > please log the width here, helps in debug...
> > 
> 
> Hum.. just a dev_dbg to log the actual width or within the dev_err ?

latter pls

> 
> >> +static u32 stm32_mdma_get_best_burst(u32 buf_len, u32 tlen, u32 max_burst,
> >> +				     enum dma_slave_buswidth width)
> >> +{
> >> +	u32 best_burst = max_burst;
> >> +	u32 burst_len = best_burst * width;
> >> +
> >> +	while ((burst_len > 0) && (tlen % burst_len)) {
> >> +		best_burst = best_burst >> 1;
> >> +		burst_len = best_burst * width;
> >> +	}
> >> +
> >> +	return (best_burst > 0) ? best_burst : 1;
> > 
> > when would best_burst <= 0? DO we really need this check
> > 
> > 
> 
> best_burst < 0 is obviously unlikely but =0 is likely whether no best burst
> found. Se we do need this check.
> 
> >> +static struct dma_async_tx_descriptor *
> >> +stm32_mdma_prep_dma_cyclic(struct dma_chan *c, dma_addr_t buf_addr,
> >> +			   size_t buf_len, size_t period_len,
> >> +			   enum dma_transfer_direction direction,
> >> +			   unsigned long flags)
> >> +{
> >> +	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
> >> +	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
> >> +	struct dma_slave_config *dma_config = &chan->dma_config;
> >> +	struct stm32_mdma_desc *desc;
> >> +	dma_addr_t src_addr, dst_addr;
> >> +	u32 ccr, ctcr, ctbr, count;
> >> +	int i, ret;
> >> +
> >> +	if (!buf_len || !period_len || period_len > STM32_MDMA_MAX_BLOCK_LEN) {
> >> +		dev_err(chan2dev(chan), "Invalid buffer/period len\n");
> >> +		return NULL;
> >> +	}
> >> +
> >> +	if (buf_len % period_len) {
> >> +		dev_err(chan2dev(chan), "buf_len not multiple of period_len\n");
> >> +		return NULL;
> >> +	}
> >> +
> >> +	/*
> >> +	 * We allow to take more number of requests till DMA is
> >> +	 * not started. The driver will loop over all requests.
> >> +	 * Once DMA is started then new requests can be queued only after
> >> +	 * terminating the DMA.
> >> +	 */
> >> +	if (chan->busy) {
> >> +		dev_err(chan2dev(chan), "Request not allowed when dma busy\n");
> >> +		return NULL;
> >> +	}
> > 
> > is that a HW restriction? Once a txn is completed can't we submit
> > subsequent txn..? Can you explain this part please.
> > 
> 
> Driver can prepare any request Slave SG, Memcpy or Cyclic. But if the channel is
> busy to complete a DMA transfer, the request will be put in pending list. This
> is only when the DMA transfer is going to be completed the next descriptor is
> going to be processed and started.
> However for cyclic this is different since when cyclic is ignited the channel
> will be busy until its termination. This is why we forbid any DMA preparation
> for this channel.
> Nonetheless I believe we have a flaw here since we have to forbid
> Slave/Memcpy/Cyclic whether a cyclic request is on-going.

But you are not submitting a txn to HW. The prepare_xxx operation prepares a
descriptor which is pushed to pending queue on submit and further pushed to
hw on queue move or issue_pending()

So here we should ideally accept the request.

After you finish memcpy you can submit a memcpy right...?

> 
> 
> >> +	if (len <= STM32_MDMA_MAX_BLOCK_LEN) {
> >> +		cbndtr |= STM32_MDMA_CBNDTR_BNDT(len);
> >> +		if (len <= STM32_MDMA_MAX_BUF_LEN) {
> >> +			/* Setup a buffer transfer */
> >> +			tlen = len;
> >> +			ccr |= STM32_MDMA_CCR_TCIE | STM32_MDMA_CCR_CTCIE;
> >> +			ctcr |= STM32_MDMA_CTCR_TRGM(STM32_MDMA_BUFFER);
> >> +			ctcr |= STM32_MDMA_CTCR_TLEN((tlen - 1));
> >> +		} else {
> >> +			/* Setup a block transfer */
> >> +			tlen = STM32_MDMA_MAX_BUF_LEN;
> >> +			ccr |= STM32_MDMA_CCR_BTIE | STM32_MDMA_CCR_CTCIE;
> >> +			ctcr |= STM32_MDMA_CTCR_TRGM(STM32_MDMA_BLOCK);
> >> +			ctcr |= STM32_MDMA_CTCR_TLEN(tlen - 1);
> >> +		}
> >> +
> >> +		/* Set best burst size */
> >> +		max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
> > 
> > that maynot be best.. we should have wider and longer burst for best
> > throughput..
> > 
> 
> Will look at that.
> 
> >> +	ret = device_property_read_u32(&pdev->dev, "dma-requests",
> >> +				       &nr_requests);
> >> +	if (ret) {
> >> +		nr_requests = STM32_MDMA_MAX_REQUESTS;
> >> +		dev_warn(&pdev->dev, "MDMA defaulting on %i request lines\n",
> >> +			 nr_requests);
> >> +	}
> >> +
> >> +	count = of_property_count_u32_elems(of_node, "st,ahb-addr-masks");
> > 
> > We dont have device_property_xxx for this?
> 
> Sorry no. Well didn't figure out one though.

we do :) the array property with NULL argument returns the size of array..

int device_property_read_u32_array(struct device *dev, const char *propname,
				   u32 *val, size_t nval)

Documentation says:
 Return: number of values if @val was %NULL,

> 
> > 
> >> +	if (count < 0)
> >> +		count = 0;
> >> +
> >> +	dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev) + sizeof(u32) * count,
> >> +			      GFP_KERNEL);
> >> +	if (!dmadev)
> >> +		return -ENOMEM;
> >> +
> >> +	dmadev->nr_channels = nr_channels;
> >> +	dmadev->nr_requests = nr_requests;
> >> +	of_property_read_u32_array(of_node, "st,ahb-addr-masks",
> >> +				   dmadev->ahb_addr_masks,
> >> +				   count);
> > 
> > i know we have an device api for array reads :)
> > and I think that helps in former case..
> > 
> 
> Correct :) device_property_read_u32_array

yes..

-- 
~Vinod

^ permalink raw reply	[flat|nested] 26+ messages in thread

* Re: [PATCH v3 2/4] dmaengine: Add STM32 MDMA driver
  2017-08-23 16:00         ` Vinod Koul
  (?)
@ 2017-08-24  8:36           ` Pierre Yves MORDRET
  -1 siblings, 0 replies; 26+ messages in thread
From: Pierre Yves MORDRET @ 2017-08-24  8:36 UTC (permalink / raw)
  To: Vinod Koul
  Cc: Rob Herring, Mark Rutland, Maxime Coquelin, Alexandre Torgue,
	Russell King, Dan Williams, M'boumba Cedric Madianga,
	Fabrice GASNIER, Herbert Xu, Fabien DESSENNE, Amelie Delaunay,
	dmaengine, devicetree, linux-arm-kernel, linux-kernel



On 08/23/2017 06:00 PM, Vinod Koul wrote:
> On Tue, Aug 22, 2017 at 05:59:26PM +0200, Pierre Yves MORDRET wrote:
>>
>>
>>>
>>> #define STM32_MDMA_SHIFT(n)		(ffs(n) - 1))
>>> #define STM32_MDMA_SET(n, mask)		((n) << STM32_MDMA_SHIFT(mask))
>>> #define STM32_MDMA_GET(n, mask)		(((n) && mask) >> STM32_MDMA_SHIFT(mask))
>>>
>>> Basically, u extract the shift using the mask value and ffs helping out, so
>>> no need to define these and reduce chances of coding errors...
>>>
>>
>> OK.
>> but I would prefer if you don't mind
> 
> hmmm, I don't have a very strong opinion, so okay. But from programming PoV
> it reduces human errors..
> 
>> #define STM32_MDMA_SET(n, mask)		(((n) << STM32_MDMA_SHIFT(mask)) & mask)
>>

I agree with your proposal :) I just said I prefer for the setter
#define STM32_MDMA_SET(n, mask)		(((n) << STM32_MDMA_SHIFT(mask)) & mask)
instead of
#define STM32_MDMA_SET(n, mask)		((n) << STM32_MDMA_SHIFT(mask))

>>>> +static int stm32_mdma_get_width(struct stm32_mdma_chan *chan,
>>>> +				enum dma_slave_buswidth width)
>>>> +{
>>>> +	switch (width) {
>>>> +	case DMA_SLAVE_BUSWIDTH_1_BYTE:
>>>> +	case DMA_SLAVE_BUSWIDTH_2_BYTES:
>>>> +	case DMA_SLAVE_BUSWIDTH_4_BYTES:
>>>> +	case DMA_SLAVE_BUSWIDTH_8_BYTES:
>>>> +		return ffs(width) - 1;
>>>> +	default:
>>>> +		dev_err(chan2dev(chan), "Dma bus width not supported\n");
>>>
>>> please log the width here, helps in debug...
>>>
>>
>> Hum.. just a dev_dbg to log the actual width or within the dev_err ?
> 
> latter pls
> 

OK

>>>> +static struct dma_async_tx_descriptor *
>>>> +stm32_mdma_prep_dma_cyclic(struct dma_chan *c, dma_addr_t buf_addr,
>>>> +			   size_t buf_len, size_t period_len,
>>>> +			   enum dma_transfer_direction direction,
>>>> +			   unsigned long flags)
>>>> +{
>>>> +	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
>>>> +	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
>>>> +	struct dma_slave_config *dma_config = &chan->dma_config;
>>>> +	struct stm32_mdma_desc *desc;
>>>> +	dma_addr_t src_addr, dst_addr;
>>>> +	u32 ccr, ctcr, ctbr, count;
>>>> +	int i, ret;
>>>> +
>>>> +	if (!buf_len || !period_len || period_len > STM32_MDMA_MAX_BLOCK_LEN) {
>>>> +		dev_err(chan2dev(chan), "Invalid buffer/period len\n");
>>>> +		return NULL;
>>>> +	}
>>>> +
>>>> +	if (buf_len % period_len) {
>>>> +		dev_err(chan2dev(chan), "buf_len not multiple of period_len\n");
>>>> +		return NULL;
>>>> +	}
>>>> +
>>>> +	/*
>>>> +	 * We allow to take more number of requests till DMA is
>>>> +	 * not started. The driver will loop over all requests.
>>>> +	 * Once DMA is started then new requests can be queued only after
>>>> +	 * terminating the DMA.
>>>> +	 */
>>>> +	if (chan->busy) {
>>>> +		dev_err(chan2dev(chan), "Request not allowed when dma busy\n");
>>>> +		return NULL;
>>>> +	}
>>>
>>> is that a HW restriction? Once a txn is completed can't we submit
>>> subsequent txn..? Can you explain this part please.
>>>
>>
>> Driver can prepare any request Slave SG, Memcpy or Cyclic. But if the channel is
>> busy to complete a DMA transfer, the request will be put in pending list. This
>> is only when the DMA transfer is going to be completed the next descriptor is
>> going to be processed and started.
>> However for cyclic this is different since when cyclic is ignited the channel
>> will be busy until its termination. This is why we forbid any DMA preparation
>> for this channel.
>> Nonetheless I believe we have a flaw here since we have to forbid
>> Slave/Memcpy/Cyclic whether a cyclic request is on-going.
> 
> But you are not submitting a txn to HW. The prepare_xxx operation prepares a
> descriptor which is pushed to pending queue on submit and further pushed to
> hw on queue move or issue_pending()
> 
> So here we should ideally accept the request.
> 
> After you finish memcpy you can submit a memcpy right...?
> 

Correct TXn is not submitted to HW only descriptors are prepared. They are going
to be pushed to HW on issue_pending if not channel not running. Otherwise the
next pending request is pushed to HW on DMA completion.
So yes I can queue a memcpy can be submitted during a memcpy (or Slave SG). The
mempy will be pushed to HW after the completion of the preceding.

The only drawback is cyclic. If a cyclic DMA operation is running, no other
requests (cyclic or SG or memcpy) can be granted or queued.

>>
>>
>>>> +	ret = device_property_read_u32(&pdev->dev, "dma-requests",
>>>> +				       &nr_requests);
>>>> +	if (ret) {
>>>> +		nr_requests = STM32_MDMA_MAX_REQUESTS;
>>>> +		dev_warn(&pdev->dev, "MDMA defaulting on %i request lines\n",
>>>> +			 nr_requests);
>>>> +	}
>>>> +
>>>> +	count = of_property_count_u32_elems(of_node, "st,ahb-addr-masks");
>>>
>>> We dont have device_property_xxx for this?
>>
>> Sorry no. Well didn't figure out one though.
> 
> we do :) the array property with NULL argument returns the size of array..
> 
> int device_property_read_u32_array(struct device *dev, const char *propname,
> 				   u32 *val, size_t nval)
> 
> Documentation says:
>  Return: number of values if @val was %NULL,
> 

Dho. ok :)

>>
>>>
>>>> +	if (count < 0)
>>>> +		count = 0;
>>>> +
>>>> +	dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev) + sizeof(u32) * count,
>>>> +			      GFP_KERNEL);
>>>> +	if (!dmadev)
>>>> +		return -ENOMEM;
>>>> +
>>>> +	dmadev->nr_channels = nr_channels;
>>>> +	dmadev->nr_requests = nr_requests;
>>>> +	of_property_read_u32_array(of_node, "st,ahb-addr-masks",
>>>> +				   dmadev->ahb_addr_masks,
>>>> +				   count);
>>>
>>> i know we have an device api for array reads :)
>>> and I think that helps in former case..
>>>
>>
>> Correct :) device_property_read_u32_array
> 
> yes..
> 

Thanks
Py

^ permalink raw reply	[flat|nested] 26+ messages in thread

* Re: [PATCH v3 2/4] dmaengine: Add STM32 MDMA driver
@ 2017-08-24  8:36           ` Pierre Yves MORDRET
  0 siblings, 0 replies; 26+ messages in thread
From: Pierre Yves MORDRET @ 2017-08-24  8:36 UTC (permalink / raw)
  To: Vinod Koul
  Cc: Rob Herring, Mark Rutland, Maxime Coquelin, Alexandre Torgue,
	Russell King, Dan Williams, M'boumba Cedric Madianga,
	Fabrice GASNIER, Herbert Xu, Fabien DESSENNE, Amelie Delaunay,
	dmaengine, devicetree, linux-arm-kernel, linux-kernel



On 08/23/2017 06:00 PM, Vinod Koul wrote:
> On Tue, Aug 22, 2017 at 05:59:26PM +0200, Pierre Yves MORDRET wrote:
>>
>>
>>>
>>> #define STM32_MDMA_SHIFT(n)		(ffs(n) - 1))
>>> #define STM32_MDMA_SET(n, mask)		((n) << STM32_MDMA_SHIFT(mask))
>>> #define STM32_MDMA_GET(n, mask)		(((n) && mask) >> STM32_MDMA_SHIFT(mask))
>>>
>>> Basically, u extract the shift using the mask value and ffs helping out, so
>>> no need to define these and reduce chances of coding errors...
>>>
>>
>> OK.
>> but I would prefer if you don't mind
> 
> hmmm, I don't have a very strong opinion, so okay. But from programming PoV
> it reduces human errors..
> 
>> #define STM32_MDMA_SET(n, mask)		(((n) << STM32_MDMA_SHIFT(mask)) & mask)
>>

I agree with your proposal :) I just said I prefer for the setter
#define STM32_MDMA_SET(n, mask)		(((n) << STM32_MDMA_SHIFT(mask)) & mask)
instead of
#define STM32_MDMA_SET(n, mask)		((n) << STM32_MDMA_SHIFT(mask))

>>>> +static int stm32_mdma_get_width(struct stm32_mdma_chan *chan,
>>>> +				enum dma_slave_buswidth width)
>>>> +{
>>>> +	switch (width) {
>>>> +	case DMA_SLAVE_BUSWIDTH_1_BYTE:
>>>> +	case DMA_SLAVE_BUSWIDTH_2_BYTES:
>>>> +	case DMA_SLAVE_BUSWIDTH_4_BYTES:
>>>> +	case DMA_SLAVE_BUSWIDTH_8_BYTES:
>>>> +		return ffs(width) - 1;
>>>> +	default:
>>>> +		dev_err(chan2dev(chan), "Dma bus width not supported\n");
>>>
>>> please log the width here, helps in debug...
>>>
>>
>> Hum.. just a dev_dbg to log the actual width or within the dev_err ?
> 
> latter pls
> 

OK

>>>> +static struct dma_async_tx_descriptor *
>>>> +stm32_mdma_prep_dma_cyclic(struct dma_chan *c, dma_addr_t buf_addr,
>>>> +			   size_t buf_len, size_t period_len,
>>>> +			   enum dma_transfer_direction direction,
>>>> +			   unsigned long flags)
>>>> +{
>>>> +	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
>>>> +	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
>>>> +	struct dma_slave_config *dma_config = &chan->dma_config;
>>>> +	struct stm32_mdma_desc *desc;
>>>> +	dma_addr_t src_addr, dst_addr;
>>>> +	u32 ccr, ctcr, ctbr, count;
>>>> +	int i, ret;
>>>> +
>>>> +	if (!buf_len || !period_len || period_len > STM32_MDMA_MAX_BLOCK_LEN) {
>>>> +		dev_err(chan2dev(chan), "Invalid buffer/period len\n");
>>>> +		return NULL;
>>>> +	}
>>>> +
>>>> +	if (buf_len % period_len) {
>>>> +		dev_err(chan2dev(chan), "buf_len not multiple of period_len\n");
>>>> +		return NULL;
>>>> +	}
>>>> +
>>>> +	/*
>>>> +	 * We allow to take more number of requests till DMA is
>>>> +	 * not started. The driver will loop over all requests.
>>>> +	 * Once DMA is started then new requests can be queued only after
>>>> +	 * terminating the DMA.
>>>> +	 */
>>>> +	if (chan->busy) {
>>>> +		dev_err(chan2dev(chan), "Request not allowed when dma busy\n");
>>>> +		return NULL;
>>>> +	}
>>>
>>> is that a HW restriction? Once a txn is completed can't we submit
>>> subsequent txn..? Can you explain this part please.
>>>
>>
>> Driver can prepare any request Slave SG, Memcpy or Cyclic. But if the channel is
>> busy to complete a DMA transfer, the request will be put in pending list. This
>> is only when the DMA transfer is going to be completed the next descriptor is
>> going to be processed and started.
>> However for cyclic this is different since when cyclic is ignited the channel
>> will be busy until its termination. This is why we forbid any DMA preparation
>> for this channel.
>> Nonetheless I believe we have a flaw here since we have to forbid
>> Slave/Memcpy/Cyclic whether a cyclic request is on-going.
> 
> But you are not submitting a txn to HW. The prepare_xxx operation prepares a
> descriptor which is pushed to pending queue on submit and further pushed to
> hw on queue move or issue_pending()
> 
> So here we should ideally accept the request.
> 
> After you finish memcpy you can submit a memcpy right...?
> 

Correct TXn is not submitted to HW only descriptors are prepared. They are going
to be pushed to HW on issue_pending if not channel not running. Otherwise the
next pending request is pushed to HW on DMA completion.
So yes I can queue a memcpy can be submitted during a memcpy (or Slave SG). The
mempy will be pushed to HW after the completion of the preceding.

The only drawback is cyclic. If a cyclic DMA operation is running, no other
requests (cyclic or SG or memcpy) can be granted or queued.

>>
>>
>>>> +	ret = device_property_read_u32(&pdev->dev, "dma-requests",
>>>> +				       &nr_requests);
>>>> +	if (ret) {
>>>> +		nr_requests = STM32_MDMA_MAX_REQUESTS;
>>>> +		dev_warn(&pdev->dev, "MDMA defaulting on %i request lines\n",
>>>> +			 nr_requests);
>>>> +	}
>>>> +
>>>> +	count = of_property_count_u32_elems(of_node, "st,ahb-addr-masks");
>>>
>>> We dont have device_property_xxx for this?
>>
>> Sorry no. Well didn't figure out one though.
> 
> we do :) the array property with NULL argument returns the size of array..
> 
> int device_property_read_u32_array(struct device *dev, const char *propname,
> 				   u32 *val, size_t nval)
> 
> Documentation says:
>  Return: number of values if @val was %NULL,
> 

Dho. ok :)

>>
>>>
>>>> +	if (count < 0)
>>>> +		count = 0;
>>>> +
>>>> +	dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev) + sizeof(u32) * count,
>>>> +			      GFP_KERNEL);
>>>> +	if (!dmadev)
>>>> +		return -ENOMEM;
>>>> +
>>>> +	dmadev->nr_channels = nr_channels;
>>>> +	dmadev->nr_requests = nr_requests;
>>>> +	of_property_read_u32_array(of_node, "st,ahb-addr-masks",
>>>> +				   dmadev->ahb_addr_masks,
>>>> +				   count);
>>>
>>> i know we have an device api for array reads :)
>>> and I think that helps in former case..
>>>
>>
>> Correct :) device_property_read_u32_array
> 
> yes..
> 

Thanks
Py

^ permalink raw reply	[flat|nested] 26+ messages in thread

* [PATCH v3 2/4] dmaengine: Add STM32 MDMA driver
@ 2017-08-24  8:36           ` Pierre Yves MORDRET
  0 siblings, 0 replies; 26+ messages in thread
From: Pierre Yves MORDRET @ 2017-08-24  8:36 UTC (permalink / raw)
  To: linux-arm-kernel



On 08/23/2017 06:00 PM, Vinod Koul wrote:
> On Tue, Aug 22, 2017 at 05:59:26PM +0200, Pierre Yves MORDRET wrote:
>>
>>
>>>
>>> #define STM32_MDMA_SHIFT(n)		(ffs(n) - 1))
>>> #define STM32_MDMA_SET(n, mask)		((n) << STM32_MDMA_SHIFT(mask))
>>> #define STM32_MDMA_GET(n, mask)		(((n) && mask) >> STM32_MDMA_SHIFT(mask))
>>>
>>> Basically, u extract the shift using the mask value and ffs helping out, so
>>> no need to define these and reduce chances of coding errors...
>>>
>>
>> OK.
>> but I would prefer if you don't mind
> 
> hmmm, I don't have a very strong opinion, so okay. But from programming PoV
> it reduces human errors..
> 
>> #define STM32_MDMA_SET(n, mask)		(((n) << STM32_MDMA_SHIFT(mask)) & mask)
>>

I agree with your proposal :) I just said I prefer for the setter
#define STM32_MDMA_SET(n, mask)		(((n) << STM32_MDMA_SHIFT(mask)) & mask)
instead of
#define STM32_MDMA_SET(n, mask)		((n) << STM32_MDMA_SHIFT(mask))

>>>> +static int stm32_mdma_get_width(struct stm32_mdma_chan *chan,
>>>> +				enum dma_slave_buswidth width)
>>>> +{
>>>> +	switch (width) {
>>>> +	case DMA_SLAVE_BUSWIDTH_1_BYTE:
>>>> +	case DMA_SLAVE_BUSWIDTH_2_BYTES:
>>>> +	case DMA_SLAVE_BUSWIDTH_4_BYTES:
>>>> +	case DMA_SLAVE_BUSWIDTH_8_BYTES:
>>>> +		return ffs(width) - 1;
>>>> +	default:
>>>> +		dev_err(chan2dev(chan), "Dma bus width not supported\n");
>>>
>>> please log the width here, helps in debug...
>>>
>>
>> Hum.. just a dev_dbg to log the actual width or within the dev_err ?
> 
> latter pls
> 

OK

>>>> +static struct dma_async_tx_descriptor *
>>>> +stm32_mdma_prep_dma_cyclic(struct dma_chan *c, dma_addr_t buf_addr,
>>>> +			   size_t buf_len, size_t period_len,
>>>> +			   enum dma_transfer_direction direction,
>>>> +			   unsigned long flags)
>>>> +{
>>>> +	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);
>>>> +	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
>>>> +	struct dma_slave_config *dma_config = &chan->dma_config;
>>>> +	struct stm32_mdma_desc *desc;
>>>> +	dma_addr_t src_addr, dst_addr;
>>>> +	u32 ccr, ctcr, ctbr, count;
>>>> +	int i, ret;
>>>> +
>>>> +	if (!buf_len || !period_len || period_len > STM32_MDMA_MAX_BLOCK_LEN) {
>>>> +		dev_err(chan2dev(chan), "Invalid buffer/period len\n");
>>>> +		return NULL;
>>>> +	}
>>>> +
>>>> +	if (buf_len % period_len) {
>>>> +		dev_err(chan2dev(chan), "buf_len not multiple of period_len\n");
>>>> +		return NULL;
>>>> +	}
>>>> +
>>>> +	/*
>>>> +	 * We allow to take more number of requests till DMA is
>>>> +	 * not started. The driver will loop over all requests.
>>>> +	 * Once DMA is started then new requests can be queued only after
>>>> +	 * terminating the DMA.
>>>> +	 */
>>>> +	if (chan->busy) {
>>>> +		dev_err(chan2dev(chan), "Request not allowed when dma busy\n");
>>>> +		return NULL;
>>>> +	}
>>>
>>> is that a HW restriction? Once a txn is completed can't we submit
>>> subsequent txn..? Can you explain this part please.
>>>
>>
>> Driver can prepare any request Slave SG, Memcpy or Cyclic. But if the channel is
>> busy to complete a DMA transfer, the request will be put in pending list. This
>> is only when the DMA transfer is going to be completed the next descriptor is
>> going to be processed and started.
>> However for cyclic this is different since when cyclic is ignited the channel
>> will be busy until its termination. This is why we forbid any DMA preparation
>> for this channel.
>> Nonetheless I believe we have a flaw here since we have to forbid
>> Slave/Memcpy/Cyclic whether a cyclic request is on-going.
> 
> But you are not submitting a txn to HW. The prepare_xxx operation prepares a
> descriptor which is pushed to pending queue on submit and further pushed to
> hw on queue move or issue_pending()
> 
> So here we should ideally accept the request.
> 
> After you finish memcpy you can submit a memcpy right...?
> 

Correct TXn is not submitted to HW only descriptors are prepared. They are going
to be pushed to HW on issue_pending if not channel not running. Otherwise the
next pending request is pushed to HW on DMA completion.
So yes I can queue a memcpy can be submitted during a memcpy (or Slave SG). The
mempy will be pushed to HW after the completion of the preceding.

The only drawback is cyclic. If a cyclic DMA operation is running, no other
requests (cyclic or SG or memcpy) can be granted or queued.

>>
>>
>>>> +	ret = device_property_read_u32(&pdev->dev, "dma-requests",
>>>> +				       &nr_requests);
>>>> +	if (ret) {
>>>> +		nr_requests = STM32_MDMA_MAX_REQUESTS;
>>>> +		dev_warn(&pdev->dev, "MDMA defaulting on %i request lines\n",
>>>> +			 nr_requests);
>>>> +	}
>>>> +
>>>> +	count = of_property_count_u32_elems(of_node, "st,ahb-addr-masks");
>>>
>>> We dont have device_property_xxx for this?
>>
>> Sorry no. Well didn't figure out one though.
> 
> we do :) the array property with NULL argument returns the size of array..
> 
> int device_property_read_u32_array(struct device *dev, const char *propname,
> 				   u32 *val, size_t nval)
> 
> Documentation says:
>  Return: number of values if @val was %NULL,
> 

Dho. ok :)

>>
>>>
>>>> +	if (count < 0)
>>>> +		count = 0;
>>>> +
>>>> +	dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev) + sizeof(u32) * count,
>>>> +			      GFP_KERNEL);
>>>> +	if (!dmadev)
>>>> +		return -ENOMEM;
>>>> +
>>>> +	dmadev->nr_channels = nr_channels;
>>>> +	dmadev->nr_requests = nr_requests;
>>>> +	of_property_read_u32_array(of_node, "st,ahb-addr-masks",
>>>> +				   dmadev->ahb_addr_masks,
>>>> +				   count);
>>>
>>> i know we have an device api for array reads :)
>>> and I think that helps in former case..
>>>
>>
>> Correct :) device_property_read_u32_array
> 
> yes..
> 

Thanks
Py

^ permalink raw reply	[flat|nested] 26+ messages in thread

end of thread, other threads:[~2017-08-24  8:37 UTC | newest]

Thread overview: 26+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-07-26  9:48 [PATCH v3 0/4] Add STM32 MDMA driver Pierre-Yves MORDRET
2017-07-26  9:48 ` Pierre-Yves MORDRET
2017-07-26  9:48 ` Pierre-Yves MORDRET
2017-07-26  9:48 ` [PATCH v3 1/4] dt-bindings: Document the STM32 MDMA bindings Pierre-Yves MORDRET
2017-07-26  9:48   ` Pierre-Yves MORDRET
2017-07-26  9:48   ` Pierre-Yves MORDRET
2017-07-26  9:48 ` [PATCH v3 2/4] dmaengine: Add STM32 MDMA driver Pierre-Yves MORDRET
2017-07-26  9:48   ` Pierre-Yves MORDRET
2017-07-26  9:48   ` Pierre-Yves MORDRET
2017-08-16 16:47   ` Vinod Koul
2017-08-16 16:47     ` Vinod Koul
2017-08-22 15:59     ` Pierre Yves MORDRET
2017-08-22 15:59       ` Pierre Yves MORDRET
2017-08-22 15:59       ` Pierre Yves MORDRET
2017-08-23 16:00       ` Vinod Koul
2017-08-23 16:00         ` Vinod Koul
2017-08-23 16:00         ` Vinod Koul
2017-08-24  8:36         ` Pierre Yves MORDRET
2017-08-24  8:36           ` Pierre Yves MORDRET
2017-08-24  8:36           ` Pierre Yves MORDRET
2017-07-26  9:48 ` [PATCH v3 3/4] ARM: dts: stm32: Add MDMA support for STM32H743 SoC Pierre-Yves MORDRET
2017-07-26  9:48   ` Pierre-Yves MORDRET
2017-07-26  9:48   ` Pierre-Yves MORDRET
2017-07-26  9:48 ` [PATCH v3 4/4] ARM: configs: stm32: Add MDMA support in STM32 defconfig Pierre-Yves MORDRET
2017-07-26  9:48   ` Pierre-Yves MORDRET
2017-07-26  9:48   ` Pierre-Yves MORDRET

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