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* [PATCH v18 0/4] Add NVIDIA Tegra GPC-DMA driver
@ 2022-02-01 15:26 Akhil R
  2022-02-01 15:26 ` [PATCH v18 1/4] dt-bindings: dmaengine: Add doc for tegra gpcdma Akhil R
                   ` (3 more replies)
  0 siblings, 4 replies; 12+ messages in thread
From: Akhil R @ 2022-02-01 15:26 UTC (permalink / raw)
  To: devicetree, dmaengine, jonathanh, kyarlagadda, ldewangan,
	linux-kernel, linux-tegra, p.zabel, rgumasta, robh+dt,
	thierry.reding, vkoul
  Cc: akhilrajeev

Add support for NVIDIA Tegra general purpose DMA driver for
Tegra186 and Tegra194 platform.

v17 -> v18:
  * Add get_residual() to get residual in tx_status()
  * Added label for device tree node so that the phandle
    can be used in client devices using the dma. 

Akhil R (4):
  dt-bindings: dmaengine: Add doc for tegra gpcdma
  dmaengine: tegra: Add tegra gpcdma driver
  arm64: defconfig: tegra: Enable GPCDMA
  arm64: tegra: Add GPCDMA node for tegra186 and tegra194

 .../bindings/dma/nvidia,tegra186-gpc-dma.yaml      |  110 ++
 arch/arm64/boot/dts/nvidia/tegra186.dtsi           |   42 +
 arch/arm64/boot/dts/nvidia/tegra194.dtsi           |   43 +
 arch/arm64/configs/defconfig                       |    1 +
 drivers/dma/Kconfig                                |   11 +
 drivers/dma/Makefile                               |    1 +
 drivers/dma/tegra186-gpc-dma.c                     | 1502 ++++++++++++++++++++
 7 files changed, 1710 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/nvidia,tegra186-gpc-dma.yaml
 create mode 100644 drivers/dma/tegra186-gpc-dma.c

-- 
2.7.4


^ permalink raw reply	[flat|nested] 12+ messages in thread

* [PATCH v18 1/4] dt-bindings: dmaengine: Add doc for tegra gpcdma
  2022-02-01 15:26 [PATCH v18 0/4] Add NVIDIA Tegra GPC-DMA driver Akhil R
@ 2022-02-01 15:26 ` Akhil R
  2022-02-01 15:26 ` [PATCH v18 2/4] dmaengine: tegra: Add tegra gpcdma driver Akhil R
                   ` (2 subsequent siblings)
  3 siblings, 0 replies; 12+ messages in thread
From: Akhil R @ 2022-02-01 15:26 UTC (permalink / raw)
  To: devicetree, dmaengine, jonathanh, kyarlagadda, ldewangan,
	linux-kernel, linux-tegra, p.zabel, rgumasta, robh+dt,
	thierry.reding, vkoul
  Cc: akhilrajeev

Add DT binding document for Nvidia Tegra GPCDMA controller.

Signed-off-by: Rajesh Gumasta <rgumasta@nvidia.com>
Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
Reviewed-by: Rob Herring <robh@kernel.org>
---
 .../bindings/dma/nvidia,tegra186-gpc-dma.yaml      | 110 +++++++++++++++++++++
 1 file changed, 110 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/nvidia,tegra186-gpc-dma.yaml

diff --git a/Documentation/devicetree/bindings/dma/nvidia,tegra186-gpc-dma.yaml b/Documentation/devicetree/bindings/dma/nvidia,tegra186-gpc-dma.yaml
new file mode 100644
index 0000000..9dd1476
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/nvidia,tegra186-gpc-dma.yaml
@@ -0,0 +1,110 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/dma/nvidia,tegra186-gpc-dma.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: NVIDIA Tegra GPC DMA Controller Device Tree Bindings
+
+description: |
+  The Tegra General Purpose Central (GPC) DMA controller is used for faster
+  data transfers between memory to memory, memory to device and device to
+  memory.
+
+maintainers:
+  - Jon Hunter <jonathanh@nvidia.com>
+  - Rajesh Gumasta <rgumasta@nvidia.com>
+
+allOf:
+  - $ref: "dma-controller.yaml#"
+
+properties:
+  compatible:
+    oneOf:
+      - const: nvidia,tegra186-gpcdma
+      - items:
+          - const: nvidia,tegra194-gpcdma
+          - const: nvidia,tegra186-gpcdma
+
+  "#dma-cells":
+    const: 1
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    description:
+      Should contain all of the per-channel DMA interrupts in
+      ascending order with respect to the DMA channel index.
+    minItems: 1
+    maxItems: 31
+
+  resets:
+    maxItems: 1
+
+  reset-names:
+    const: gpcdma
+
+  iommus:
+    maxItems: 1
+
+  dma-coherent: true
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - resets
+  - reset-names
+  - "#dma-cells"
+  - iommus
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/memory/tegra186-mc.h>
+    #include <dt-bindings/reset/tegra186-reset.h>
+
+    dma-controller@2600000 {
+        compatible = "nvidia,tegra186-gpcdma";
+        reg = <0x2600000 0x210000>;
+        resets = <&bpmp TEGRA186_RESET_GPCDMA>;
+        reset-names = "gpcdma";
+        interrupts = <GIC_SPI 76 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 77 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 78 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 79 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 80 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 81 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 82 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 83 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 84 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 85 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 86 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 87 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 88 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 89 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 90 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 91 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 92 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 93 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 94 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 95 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 96 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 97 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 98 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 99 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 100 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 101 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 102 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 103 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 104 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 105 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 106 IRQ_TYPE_LEVEL_HIGH>;
+        #dma-cells = <1>;
+        iommus = <&smmu TEGRA186_SID_GPCDMA_0>;
+        dma-coherent;
+    };
+...
-- 
2.7.4


^ permalink raw reply related	[flat|nested] 12+ messages in thread

* [PATCH v18 2/4] dmaengine: tegra: Add tegra gpcdma driver
  2022-02-01 15:26 [PATCH v18 0/4] Add NVIDIA Tegra GPC-DMA driver Akhil R
  2022-02-01 15:26 ` [PATCH v18 1/4] dt-bindings: dmaengine: Add doc for tegra gpcdma Akhil R
@ 2022-02-01 15:26 ` Akhil R
  2022-02-02 15:45   ` Dmitry Osipenko
  2022-02-03  0:18   ` kernel test robot
  2022-02-01 15:26 ` [PATCH v18 3/4] arm64: defconfig: tegra: Enable GPCDMA Akhil R
  2022-02-01 15:26 ` [PATCH v18 4/4] arm64: tegra: Add GPCDMA node for tegra186 and tegra194 Akhil R
  3 siblings, 2 replies; 12+ messages in thread
From: Akhil R @ 2022-02-01 15:26 UTC (permalink / raw)
  To: devicetree, dmaengine, jonathanh, kyarlagadda, ldewangan,
	linux-kernel, linux-tegra, p.zabel, rgumasta, robh+dt,
	thierry.reding, vkoul
  Cc: akhilrajeev, Pavan Kunapuli

Adding GPC DMA controller driver for Tegra. The driver supports dma
transfers between memory to memory, IO peripheral to memory and
memory to IO peripheral.

Co-developed-by: Pavan Kunapuli <pkunapuli@nvidia.com>
Signed-off-by: Pavan Kunapuli <pkunapuli@nvidia.com>
Co-developed-by: Rajesh Gumasta <rgumasta@nvidia.com>
Signed-off-by: Rajesh Gumasta <rgumasta@nvidia.com>
Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
---
 drivers/dma/Kconfig            |   11 +
 drivers/dma/Makefile           |    1 +
 drivers/dma/tegra186-gpc-dma.c | 1502 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 1514 insertions(+)
 create mode 100644 drivers/dma/tegra186-gpc-dma.c

diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 6bcdb4e..dbe7664 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -629,6 +629,17 @@ config TXX9_DMAC
 	  Support the TXx9 SoC internal DMA controller.  This can be
 	  integrated in chips such as the Toshiba TX4927/38/39.
 
+config TEGRA186_GPC_DMA
+	tristate "NVIDIA Tegra GPC DMA support"
+	depends on ARCH_TEGRA || COMPILE_TEST
+	select DMA_ENGINE
+	help
+	  Support for the NVIDIA Tegra General Purpose Central DMA controller.
+	  The DMA controller has multiple DMA channels which can be configured
+	  for different peripherals like UART, SPI, etc which are on APB bus.
+	  This DMA controller transfers data from memory to peripheral FIFO
+	  or vice versa. It also supports memory to memory data transfer.
+
 config TEGRA20_APB_DMA
 	tristate "NVIDIA Tegra20 APB DMA support"
 	depends on ARCH_TEGRA || COMPILE_TEST
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index 616d926..2f1b87f 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -72,6 +72,7 @@ obj-$(CONFIG_STM32_MDMA) += stm32-mdma.o
 obj-$(CONFIG_SPRD_DMA) += sprd-dma.o
 obj-$(CONFIG_S3C24XX_DMAC) += s3c24xx-dma.o
 obj-$(CONFIG_TXX9_DMAC) += txx9dmac.o
+obj-$(CONFIG_TEGRA186_GPC_DMA) += tegra186-gpc-dma.o
 obj-$(CONFIG_TEGRA20_APB_DMA) += tegra20-apb-dma.o
 obj-$(CONFIG_TEGRA210_ADMA) += tegra210-adma.o
 obj-$(CONFIG_TIMB_DMA) += timb_dma.o
diff --git a/drivers/dma/tegra186-gpc-dma.c b/drivers/dma/tegra186-gpc-dma.c
new file mode 100644
index 0000000..bc923f0
--- /dev/null
+++ b/drivers/dma/tegra186-gpc-dma.c
@@ -0,0 +1,1502 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * DMA driver for NVIDIA Tegra GPC DMA controller.
+ *
+ * Copyright (c) 2014 - 2022, NVIDIA CORPORATION.  All rights reserved.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/interrupt.h>
+#include <linux/iommu.h>
+#include <linux/iopoll.h>
+#include <linux/minmax.h>
+#include <linux/module.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 <linux/version.h>
+#include <dt-bindings/memory/tegra186-mc.h>
+#include "virt-dma.h"
+
+/* CSR register */
+#define TEGRA_GPCDMA_CHAN_CSR			0x00
+#define TEGRA_GPCDMA_CSR_ENB			BIT(31)
+#define TEGRA_GPCDMA_CSR_IE_EOC			BIT(30)
+#define TEGRA_GPCDMA_CSR_ONCE			BIT(27)
+
+#define TEGRA_GPCDMA_CSR_FC_MODE		GENMASK(25, 24)
+#define TEGRA_GPCDMA_CSR_FC_MODE_NO_MMIO	\
+					FIELD_PREP(TEGRA_GPCDMA_CSR_FC_MODE, 0)
+#define TEGRA_GPCDMA_CSR_FC_MODE_ONE_MMIO	\
+					FIELD_PREP(TEGRA_GPCDMA_CSR_FC_MODE, 1)
+#define TEGRA_GPCDMA_CSR_FC_MODE_TWO_MMIO	\
+					FIELD_PREP(TEGRA_GPCDMA_CSR_FC_MODE, 2)
+#define TEGRA_GPCDMA_CSR_FC_MODE_FOUR_MMIO	\
+					FIELD_PREP(TEGRA_GPCDMA_CSR_FC_MODE, 3)
+
+#define TEGRA_GPCDMA_CSR_DMA			GENMASK(23, 21)
+#define TEGRA_GPCDMA_CSR_DMA_IO2MEM_NO_FC	\
+					FIELD_PREP(TEGRA_GPCDMA_CSR_DMA, 0)
+#define TEGRA_GPCDMA_CSR_DMA_IO2MEM_FC		\
+					FIELD_PREP(TEGRA_GPCDMA_CSR_DMA, 1)
+#define TEGRA_GPCDMA_CSR_DMA_MEM2IO_NO_FC	\
+					FIELD_PREP(TEGRA_GPCDMA_CSR_DMA, 2)
+#define TEGRA_GPCDMA_CSR_DMA_MEM2IO_FC		\
+					FIELD_PREP(TEGRA_GPCDMA_CSR_DMA, 3)
+#define TEGRA_GPCDMA_CSR_DMA_MEM2MEM		\
+					FIELD_PREP(TEGRA_GPCDMA_CSR_DMA, 4)
+#define TEGRA_GPCDMA_CSR_DMA_FIXED_PAT		\
+					FIELD_PREP(TEGRA_GPCDMA_CSR_DMA, 6)
+
+#define TEGRA_GPCDMA_CSR_REQ_SEL_MASK		GENMASK(20, 16)
+#define TEGRA_GPCDMA_CSR_REQ_SEL_UNUSED		\
+					FIELD_PREP(TEGRA_GPCDMA_CSR_REQ_SEL_MASK, 4)
+#define TEGRA_GPCDMA_CSR_IRQ_MASK		BIT(15)
+#define TEGRA_GPCDMA_CSR_WEIGHT			GENMASK(13, 10)
+
+/* STATUS register */
+#define TEGRA_GPCDMA_CHAN_STATUS		0x004
+#define TEGRA_GPCDMA_STATUS_BUSY		BIT(31)
+#define TEGRA_GPCDMA_STATUS_ISE_EOC		BIT(30)
+#define TEGRA_GPCDMA_STATUS_PING_PONG		BIT(28)
+#define TEGRA_GPCDMA_STATUS_DMA_ACTIVITY	BIT(27)
+#define TEGRA_GPCDMA_STATUS_CHANNEL_PAUSE	BIT(26)
+#define TEGRA_GPCDMA_STATUS_CHANNEL_RX		BIT(25)
+#define TEGRA_GPCDMA_STATUS_CHANNEL_TX		BIT(24)
+#define TEGRA_GPCDMA_STATUS_IRQ_INTR_STA	BIT(23)
+#define TEGRA_GPCDMA_STATUS_IRQ_STA		BIT(21)
+#define TEGRA_GPCDMA_STATUS_IRQ_TRIG_STA	BIT(20)
+
+#define TEGRA_GPCDMA_CHAN_CSRE			0x008
+#define TEGRA_GPCDMA_CHAN_CSRE_PAUSE		BIT(31)
+
+/* Source address */
+#define TEGRA_GPCDMA_CHAN_SRC_PTR		0x00C
+
+/* Destination address */
+#define TEGRA_GPCDMA_CHAN_DST_PTR		0x010
+
+/* High address pointer */
+#define TEGRA_GPCDMA_CHAN_HIGH_ADDR_PTR		0x014
+#define TEGRA_GPCDMA_HIGH_ADDR_SRC_PTR		GENMASK(7, 0)
+#define TEGRA_GPCDMA_HIGH_ADDR_DST_PTR		GENMASK(23, 16)
+
+/* MC sequence register */
+#define TEGRA_GPCDMA_CHAN_MCSEQ			0x18
+#define TEGRA_GPCDMA_MCSEQ_DATA_SWAP		BIT(31)
+#define TEGRA_GPCDMA_MCSEQ_REQ_COUNT		GENMASK(30, 25)
+#define TEGRA_GPCDMA_MCSEQ_BURST		GENMASK(24, 23)
+#define TEGRA_GPCDMA_MCSEQ_BURST_2		\
+					FIELD_PREP(TEGRA_GPCDMA_MCSEQ_BURST, 0)
+#define TEGRA_GPCDMA_MCSEQ_BURST_16		\
+					FIELD_PREP(TEGRA_GPCDMA_MCSEQ_BURST, 3)
+#define TEGRA_GPCDMA_MCSEQ_WRAP1		GENMASK(22, 20)
+#define TEGRA_GPCDMA_MCSEQ_WRAP0		GENMASK(19, 17)
+#define TEGRA_GPCDMA_MCSEQ_WRAP_NONE		0
+
+#define TEGRA_GPCDMA_MCSEQ_STREAM_ID1_MASK	GENMASK(13, 7)
+#define TEGRA_GPCDMA_MCSEQ_STREAM_ID0_MASK	GENMASK(6, 0)
+
+/* MMIO sequence register */
+#define TEGRA_GPCDMA_CHAN_MMIOSEQ			0x01c
+#define TEGRA_GPCDMA_MMIOSEQ_DBL_BUF		BIT(31)
+#define TEGRA_GPCDMA_MMIOSEQ_BUS_WIDTH		GENMASK(30, 28)
+#define TEGRA_GPCDMA_MMIOSEQ_BUS_WIDTH_8	\
+					FIELD_PREP(TEGRA_GPCDMA_MMIOSEQ_BUS_WIDTH, 0)
+#define TEGRA_GPCDMA_MMIOSEQ_BUS_WIDTH_16	\
+					FIELD_PREP(TEGRA_GPCDMA_MMIOSEQ_BUS_WIDTH, 1)
+#define TEGRA_GPCDMA_MMIOSEQ_BUS_WIDTH_32	\
+					FIELD_PREP(TEGRA_GPCDMA_MMIOSEQ_BUS_WIDTH, 2)
+#define TEGRA_GPCDMA_MMIOSEQ_DATA_SWAP		BIT(27)
+#define TEGRA_GPCDMA_MMIOSEQ_BURST_SHIFT	23
+#define TEGRA_GPCDMA_MMIOSEQ_BURST_MIN		2U
+#define TEGRA_GPCDMA_MMIOSEQ_BURST_MAX		32U
+#define TEGRA_GPCDMA_MMIOSEQ_BURST(bs)	\
+		(GENMASK((fls(bs) - 2), 0) << TEGRA_GPCDMA_MMIOSEQ_BURST_SHIFT)
+#define TEGRA_GPCDMA_MMIOSEQ_MASTER_ID		GENMASK(22, 19)
+#define TEGRA_GPCDMA_MMIOSEQ_WRAP_WORD		GENMASK(18, 16)
+#define TEGRA_GPCDMA_MMIOSEQ_MMIO_PROT		GENMASK(8, 7)
+
+/* Channel WCOUNT */
+#define TEGRA_GPCDMA_CHAN_WCOUNT		0x20
+
+/* Transfer count */
+#define TEGRA_GPCDMA_CHAN_XFER_COUNT		0x24
+
+/* DMA byte count status */
+#define TEGRA_GPCDMA_CHAN_DMA_BYTE_STATUS	0x28
+
+/* Error Status Register */
+#define TEGRA_GPCDMA_CHAN_ERR_STATUS		0x30
+#define TEGRA_GPCDMA_CHAN_ERR_TYPE_SHIFT	8
+#define TEGRA_GPCDMA_CHAN_ERR_TYPE_MASK	0xF
+#define TEGRA_GPCDMA_CHAN_ERR_TYPE(err)	(			\
+		((err) >> TEGRA_GPCDMA_CHAN_ERR_TYPE_SHIFT) &	\
+		TEGRA_GPCDMA_CHAN_ERR_TYPE_MASK)
+#define TEGRA_DMA_BM_FIFO_FULL_ERR		0xF
+#define TEGRA_DMA_PERIPH_FIFO_FULL_ERR		0xE
+#define TEGRA_DMA_PERIPH_ID_ERR			0xD
+#define TEGRA_DMA_STREAM_ID_ERR			0xC
+#define TEGRA_DMA_MC_SLAVE_ERR			0xB
+#define TEGRA_DMA_MMIO_SLAVE_ERR		0xA
+
+/* Fixed Pattern */
+#define TEGRA_GPCDMA_CHAN_FIXED_PATTERN		0x34
+
+#define TEGRA_GPCDMA_CHAN_TZ			0x38
+#define TEGRA_GPCDMA_CHAN_TZ_MMIO_PROT_1	BIT(0)
+#define TEGRA_GPCDMA_CHAN_TZ_MC_PROT_1		BIT(1)
+
+#define TEGRA_GPCDMA_CHAN_SPARE			0x3c
+#define TEGRA_GPCDMA_CHAN_SPARE_EN_LEGACY_FC	BIT(16)
+
+/*
+ * If any burst is in flight and DMA paused then this is the time to complete
+ * on-flight burst and update DMA status register.
+ */
+#define TEGRA_GPCDMA_BURST_COMPLETE_TIME	20
+#define TEGRA_GPCDMA_BURST_COMPLETION_TIMEOUT	100
+
+/* Channel base address offset from GPCDMA base address */
+#define TEGRA_GPCDMA_CHANNEL_BASE_ADD_OFFSET	0x20000
+
+struct tegra_dma;
+
+/*
+ * tegra_dma_chip_data Tegra chip specific DMA data
+ * @nr_channels: Number of channels available in the controller.
+ * @channel_reg_size: Channel register size.
+ * @max_dma_count: Maximum DMA transfer count supported by DMA controller.
+ * @hw_support_pause: DMA HW engine support pause of the channel.
+ */
+struct tegra_dma_chip_data {
+	unsigned int nr_channels;
+	unsigned int channel_reg_size;
+	unsigned int max_dma_count;
+	bool hw_support_pause;
+};
+
+/* DMA channel registers */
+struct tegra_dma_channel_regs {
+	unsigned long csr;
+	unsigned long src_ptr;
+	unsigned long dst_ptr;
+	unsigned long high_addr_ptr;
+	unsigned long mc_seq;
+	unsigned long mmio_seq;
+	unsigned long wcount;
+	unsigned long fixed_pattern;
+};
+
+/*
+ * tegra_dma_sg_req: Dma request details to configure hardware. This
+ * contains the details for one transfer to configure DMA hw.
+ * The client's request for data transfer can be broken into multiple
+ * sub-transfer as per requester details and hw support. This sub transfer
+ * get added as an array in Tegra DMA desc which manages the transfer details.
+ */
+struct tegra_dma_sg_req {
+	unsigned int len;
+	struct tegra_dma_channel_regs ch_regs;
+};
+
+/*
+ * tegra_dma_desc: Tegra DMA descriptors which uses virt_dma_desc to
+ * manage client request and keep track of transfer status, callbacks
+ * and request counts etc.
+ */
+struct tegra_dma_desc {
+	struct virt_dma_desc vd;
+	unsigned int bytes_req;
+	unsigned int bytes_xfer;
+	unsigned int sg_idx;
+	unsigned int sg_count;
+	bool cyclic;
+	struct tegra_dma_channel *tdc;
+	struct tegra_dma_sg_req sg_req[];
+};
+
+/*
+ * tegra_dma_channel: Channel specific information
+ */
+struct tegra_dma_channel {
+	struct virt_dma_chan vc;
+	struct tegra_dma_desc *dma_desc;
+	char name[30];
+	bool config_init;
+	int id;
+	int irq;
+	unsigned int stream_id;
+	unsigned long chan_base_offset;
+	struct tegra_dma *tdma;
+	int slave_id;
+	enum dma_transfer_direction sid_dir;
+	struct dma_slave_config dma_sconfig;
+};
+
+/*
+ * tegra_dma: Tegra DMA specific information
+ */
+struct tegra_dma {
+	struct dma_device dma_dev;
+	struct device *dev;
+	void __iomem *base_addr;
+	const struct tegra_dma_chip_data *chip_data;
+	struct reset_control *rst;
+	unsigned long sid_m2d_reserved;
+	unsigned long sid_d2m_reserved;
+	struct tegra_dma_channel channels[];
+};
+
+static inline void tdc_write(struct tegra_dma_channel *tdc,
+			     u32 reg, u32 val)
+{
+	writel_relaxed(val, tdc->tdma->base_addr + tdc->chan_base_offset + reg);
+}
+
+static inline u32 tdc_read(struct tegra_dma_channel *tdc, u32 reg)
+{
+	return readl_relaxed(tdc->tdma->base_addr + tdc->chan_base_offset + reg);
+}
+
+static inline struct tegra_dma_channel *to_tegra_dma_chan(struct dma_chan *dc)
+{
+	return container_of(dc, struct tegra_dma_channel, vc.chan);
+}
+
+static inline struct tegra_dma_desc *vd_to_tegra_dma_desc(struct virt_dma_desc *vd)
+{
+	return container_of(vd, struct tegra_dma_desc, vd);
+}
+
+static inline struct device *tdc2dev(struct tegra_dma_channel *tdc)
+{
+	return tdc->vc.chan.device->dev;
+}
+
+static void tegra_dma_dump_chan_regs(struct tegra_dma_channel *tdc)
+{
+	dev_dbg(tdc2dev(tdc), "DMA Channel %d name %s register dump:\n",
+		tdc->id, tdc->name);
+	dev_dbg(tdc2dev(tdc), "CSR %x STA %x CSRE %x SRC %x DST %x\n",
+		tdc_read(tdc, TEGRA_GPCDMA_CHAN_CSR),
+		tdc_read(tdc, TEGRA_GPCDMA_CHAN_STATUS),
+		tdc_read(tdc, TEGRA_GPCDMA_CHAN_CSRE),
+		tdc_read(tdc, TEGRA_GPCDMA_CHAN_SRC_PTR),
+		tdc_read(tdc, TEGRA_GPCDMA_CHAN_DST_PTR)
+	);
+	dev_dbg(tdc2dev(tdc), "MCSEQ %x IOSEQ %x WCNT %x XFER %x BSTA %x\n",
+		tdc_read(tdc, TEGRA_GPCDMA_CHAN_MCSEQ),
+		tdc_read(tdc, TEGRA_GPCDMA_CHAN_MMIOSEQ),
+		tdc_read(tdc, TEGRA_GPCDMA_CHAN_WCOUNT),
+		tdc_read(tdc, TEGRA_GPCDMA_CHAN_XFER_COUNT),
+		tdc_read(tdc, TEGRA_GPCDMA_CHAN_DMA_BYTE_STATUS)
+	);
+	dev_dbg(tdc2dev(tdc), "DMA ERR_STA %x\n",
+		tdc_read(tdc, TEGRA_GPCDMA_CHAN_ERR_STATUS));
+}
+
+static int tegra_dma_sid_reserve(struct tegra_dma_channel *tdc,
+				 enum dma_transfer_direction direction)
+{
+	struct tegra_dma *tdma = tdc->tdma;
+	unsigned int sid = tdc->slave_id;
+
+	if (!is_slave_direction(direction))
+		return 0;
+
+	switch (direction) {
+	case DMA_MEM_TO_DEV:
+		if (test_and_set_bit(sid, &tdma->sid_m2d_reserved)) {
+			dev_err(tdma->dev, "slave id already in use\n");
+			return -EINVAL;
+		}
+		break;
+	case DMA_DEV_TO_MEM:
+		if (test_and_set_bit(sid, &tdma->sid_d2m_reserved)) {
+			dev_err(tdma->dev, "slave id already in use\n");
+			return -EINVAL;
+		}
+		break;
+	default:
+		break;
+	}
+
+	tdc->sid_dir = direction;
+
+	return 0;
+}
+
+static void tegra_dma_sid_free(struct tegra_dma_channel *tdc)
+{
+	struct tegra_dma *tdma = tdc->tdma;
+	unsigned int sid = tdc->slave_id;
+
+	switch (tdc->sid_dir) {
+	case DMA_MEM_TO_DEV:
+		clear_bit(sid,  &tdma->sid_m2d_reserved);
+		break;
+	case DMA_DEV_TO_MEM:
+		clear_bit(sid,  &tdma->sid_d2m_reserved);
+		break;
+	default:
+		break;
+	}
+
+	tdc->sid_dir = DMA_TRANS_NONE;
+}
+
+static void tegra_dma_desc_free(struct virt_dma_desc *vd)
+{
+	kfree(container_of(vd, struct tegra_dma_desc, vd));
+}
+
+static int tegra_dma_slave_config(struct dma_chan *dc,
+				  struct dma_slave_config *sconfig)
+{
+	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
+
+	memcpy(&tdc->dma_sconfig, sconfig, sizeof(*sconfig));
+	tdc->config_init = true;
+
+	return 0;
+}
+
+static int tegra_dma_pause(struct tegra_dma_channel *tdc)
+{
+	int ret;
+	u32 val;
+
+	val = tdc_read(tdc, TEGRA_GPCDMA_CHAN_CSRE);
+	val |= TEGRA_GPCDMA_CHAN_CSRE_PAUSE;
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_CSRE, val);
+
+	/* Wait until busy bit is de-asserted */
+	ret = readl_relaxed_poll_timeout_atomic(tdc->tdma->base_addr +
+			tdc->chan_base_offset + TEGRA_GPCDMA_CHAN_STATUS,
+			val,
+			!(val & TEGRA_GPCDMA_STATUS_BUSY),
+			TEGRA_GPCDMA_BURST_COMPLETE_TIME,
+			TEGRA_GPCDMA_BURST_COMPLETION_TIMEOUT);
+
+	return ret;
+}
+
+static int tegra_dma_device_pause(struct dma_chan *dc)
+{
+	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
+	unsigned long flags;
+	int ret = 0;
+
+	if (!tdc->tdma->chip_data->hw_support_pause)
+		return -ENOSYS;
+
+	spin_lock_irqsave(&tdc->vc.lock, flags);
+	ret = tegra_dma_pause(tdc);
+	if (ret)
+		dev_err(tdc2dev(tdc), "DMA pause timed out\n");
+
+	spin_unlock_irqrestore(&tdc->vc.lock, flags);
+
+	return ret;
+}
+
+static void tegra_dma_resume(struct tegra_dma_channel *tdc)
+{
+	u32 val;
+
+	val = tdc_read(tdc, TEGRA_GPCDMA_CHAN_CSRE);
+	val &= ~TEGRA_GPCDMA_CHAN_CSRE_PAUSE;
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_CSRE, val);
+}
+
+static int tegra_dma_device_resume(struct dma_chan *dc)
+{
+	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
+	unsigned long flags;
+
+	if (!tdc->tdma->chip_data->hw_support_pause)
+		return -ENOSYS;
+
+	spin_lock_irqsave(&tdc->vc.lock, flags);
+	tegra_dma_resume(tdc);
+	spin_unlock_irqrestore(&tdc->vc.lock, flags);
+
+	return 0;
+}
+
+static void tegra_dma_stop(struct tegra_dma_channel *tdc)
+{
+	u32 csr, status;
+
+	csr = tdc_read(tdc, TEGRA_GPCDMA_CHAN_CSR);
+
+	/* Disable interrupts */
+	csr &= ~TEGRA_GPCDMA_CSR_IE_EOC;
+
+	/* Disable DMA */
+	csr &= ~TEGRA_GPCDMA_CSR_ENB;
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_CSR, csr);
+
+	/* Clear interrupt status if it is there */
+	status = tdc_read(tdc, TEGRA_GPCDMA_CHAN_STATUS);
+	if (status & TEGRA_GPCDMA_STATUS_ISE_EOC) {
+		dev_dbg(tdc2dev(tdc), "%s():clearing interrupt\n", __func__);
+		tdc_write(tdc, TEGRA_GPCDMA_CHAN_STATUS, status);
+	}
+}
+
+static void tegra_dma_configure_next_sg(struct tegra_dma_channel *tdc)
+{
+	struct tegra_dma_desc *dma_desc = tdc->dma_desc;
+	struct tegra_dma_channel_regs *ch_regs;
+	int err;
+	u32 val;
+
+	/* Configure next transfer immediately after DMA is busy */
+	err = readl_relaxed_poll_timeout_atomic(tdc->tdma->base_addr +
+			tdc->chan_base_offset + TEGRA_GPCDMA_CHAN_STATUS,
+			val,
+			(val & TEGRA_GPCDMA_STATUS_BUSY), 0,
+			TEGRA_GPCDMA_BURST_COMPLETION_TIMEOUT);
+	if (err)
+		return;
+
+	ch_regs = &dma_desc->sg_req[dma_desc->sg_idx].ch_regs;
+
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_WCOUNT, ch_regs->wcount);
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_SRC_PTR, ch_regs->src_ptr);
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_DST_PTR, ch_regs->dst_ptr);
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_HIGH_ADDR_PTR, ch_regs->high_addr_ptr);
+
+	/* Start DMA */
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_CSR,
+		  ch_regs->csr | TEGRA_GPCDMA_CSR_ENB);
+
+	dma_desc->sg_idx++;
+
+	/* Reset the sg index for cyclic transfers */
+	if (dma_desc->sg_idx == dma_desc->sg_count)
+		dma_desc->sg_idx = 0;
+}
+
+static void tegra_dma_start(struct tegra_dma_channel *tdc)
+{
+	struct tegra_dma_desc *dma_desc = tdc->dma_desc;
+	struct tegra_dma_channel_regs *ch_regs;
+	struct virt_dma_desc *vdesc;
+
+	if (!dma_desc) {
+		vdesc = vchan_next_desc(&tdc->vc);
+		if (!vdesc)
+			return;
+
+		dma_desc = vd_to_tegra_dma_desc(vdesc);
+		list_del(&vdesc->node);
+		dma_desc->tdc = tdc;
+		tdc->dma_desc = dma_desc;
+
+		tegra_dma_resume(tdc);
+	}
+
+	ch_regs = &dma_desc->sg_req[dma_desc->sg_idx].ch_regs;
+
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_WCOUNT, ch_regs->wcount);
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_CSR, 0);
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_SRC_PTR, ch_regs->src_ptr);
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_DST_PTR, ch_regs->dst_ptr);
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_HIGH_ADDR_PTR, ch_regs->high_addr_ptr);
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_FIXED_PATTERN, ch_regs->fixed_pattern);
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_MMIOSEQ, ch_regs->mmio_seq);
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_MCSEQ, ch_regs->mc_seq);
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_CSR, ch_regs->csr);
+
+	/* Start DMA */
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_CSR,
+		  ch_regs->csr | TEGRA_GPCDMA_CSR_ENB);
+
+	dma_desc->sg_idx++;
+}
+
+static void tegra_dma_xfer_complete(struct tegra_dma_channel *tdc)
+{
+	vchan_cookie_complete(&tdc->dma_desc->vd);
+
+	tegra_dma_sid_free(tdc);
+	tdc->dma_desc = NULL;
+}
+
+static void tegra_dma_chan_decode_error(struct tegra_dma_channel *tdc,
+					unsigned int err_status)
+{
+	switch (TEGRA_GPCDMA_CHAN_ERR_TYPE(err_status)) {
+	case TEGRA_DMA_BM_FIFO_FULL_ERR:
+		dev_err(tdc->tdma->dev,
+			"GPCDMA CH%d bm fifo full\n", tdc->id);
+		break;
+
+	case TEGRA_DMA_PERIPH_FIFO_FULL_ERR:
+		dev_err(tdc->tdma->dev,
+			"GPCDMA CH%d peripheral fifo full\n", tdc->id);
+		break;
+
+	case TEGRA_DMA_PERIPH_ID_ERR:
+		dev_err(tdc->tdma->dev,
+			"GPCDMA CH%d illegal peripheral id\n", tdc->id);
+		break;
+
+	case TEGRA_DMA_STREAM_ID_ERR:
+		dev_err(tdc->tdma->dev,
+			"GPCDMA CH%d illegal stream id\n", tdc->id);
+		break;
+
+	case TEGRA_DMA_MC_SLAVE_ERR:
+		dev_err(tdc->tdma->dev,
+			"GPCDMA CH%d mc slave error\n", tdc->id);
+		break;
+
+	case TEGRA_DMA_MMIO_SLAVE_ERR:
+		dev_err(tdc->tdma->dev,
+			"GPCDMA CH%d mmio slave error\n", tdc->id);
+		break;
+
+	default:
+		dev_err(tdc->tdma->dev,
+			"GPCDMA CH%d security violation %x\n", tdc->id,
+			err_status);
+	}
+}
+
+static irqreturn_t tegra_dma_isr(int irq, void *dev_id)
+{
+	struct tegra_dma_channel *tdc = dev_id;
+	struct tegra_dma_desc *dma_desc = tdc->dma_desc;
+	struct tegra_dma_sg_req *sg_req;
+	u32 status;
+
+	/* Check channel error status register */
+	status = tdc_read(tdc, TEGRA_GPCDMA_CHAN_ERR_STATUS);
+	if (status) {
+		tegra_dma_chan_decode_error(tdc, status);
+		tegra_dma_dump_chan_regs(tdc);
+		tdc_write(tdc, TEGRA_GPCDMA_CHAN_ERR_STATUS, 0xFFFFFFFF);
+	}
+
+	spin_lock(&tdc->vc.lock);
+	status = tdc_read(tdc, TEGRA_GPCDMA_CHAN_STATUS);
+	if (!(status & TEGRA_GPCDMA_STATUS_ISE_EOC))
+		goto irq_done;
+
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_STATUS,
+		  TEGRA_GPCDMA_STATUS_ISE_EOC);
+
+	if (!dma_desc)
+		goto irq_done;
+
+	sg_req = dma_desc->sg_req;
+	dma_desc->bytes_xfer += sg_req[dma_desc->sg_idx - 1].len;
+
+	if (dma_desc->sg_idx == dma_desc->sg_count) {
+		tegra_dma_xfer_complete(tdc);
+	} else if (dma_desc->cyclic) {
+		vchan_cyclic_callback(&dma_desc->vd);
+		tegra_dma_configure_next_sg(tdc);
+	} else {
+		tegra_dma_start(tdc);
+	}
+
+irq_done:
+	spin_unlock(&tdc->vc.lock);
+	return IRQ_HANDLED;
+}
+
+static void tegra_dma_issue_pending(struct dma_chan *dc)
+{
+	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
+	unsigned long flags;
+
+	if (tdc->dma_desc)
+		return;
+
+	spin_lock_irqsave(&tdc->vc.lock, flags);
+	if (vchan_issue_pending(&tdc->vc))
+		tegra_dma_start(tdc);
+
+	/*
+	 * For cyclic dma transfers, program the second
+	 * transfer parameters as soon as the first dma
+	 * transfer is started inorder for the dma
+	 * controller to trigger the second transfer
+	 * with the correct parameters.
+	 */
+	if (tdc->dma_desc && tdc->dma_desc->cyclic)
+		tegra_dma_configure_next_sg(tdc);
+
+	spin_unlock_irqrestore(&tdc->vc.lock, flags);
+}
+
+static int tegra_dma_stop_client(struct tegra_dma_channel *tdc)
+{
+	int ret;
+	unsigned long status;
+	u32 csr = tdc_read(tdc, TEGRA_GPCDMA_CHAN_CSR);
+
+	/*
+	 * Change the client associated with the DMA channel
+	 * to stop DMA engine from starting any more bursts for
+	 * the given client and wait for in flight bursts to complete
+	 */
+	csr &= ~(TEGRA_GPCDMA_CSR_REQ_SEL_MASK);
+	csr |= TEGRA_GPCDMA_CSR_REQ_SEL_UNUSED;
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_CSR, csr);
+
+	/* Wait for in flight data transfer to finish */
+	udelay(TEGRA_GPCDMA_BURST_COMPLETE_TIME);
+
+	/* If TX/RX path is still active wait till it becomes
+	 * inactive
+	 */
+
+	ret = readl_relaxed_poll_timeout_atomic(tdc->tdma->base_addr +
+				tdc->chan_base_offset +
+				TEGRA_GPCDMA_CHAN_STATUS,
+				status,
+				!(status & (TEGRA_GPCDMA_STATUS_CHANNEL_TX |
+				TEGRA_GPCDMA_STATUS_CHANNEL_RX)),
+				5,
+				TEGRA_GPCDMA_BURST_COMPLETION_TIMEOUT);
+	if (ret) {
+		dev_err(tdc2dev(tdc), "Timeout waiting for DMA burst completion!\n");
+		tegra_dma_dump_chan_regs(tdc);
+	}
+
+	return ret;
+}
+
+static int tegra_dma_terminate_all(struct dma_chan *dc)
+{
+	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
+	unsigned long flags;
+	LIST_HEAD(head);
+	int err;
+
+	spin_lock_irqsave(&tdc->vc.lock, flags);
+
+	if (tdc->dma_desc) {
+		err = tdc->tdma->chip_data->hw_support_pause ?
+		      tegra_dma_pause(tdc) :
+		      tegra_dma_stop_client(tdc);
+		if (err) {
+			spin_unlock_irqrestore(&tdc->vc.lock, flags);
+			return err;
+		}
+
+		tegra_dma_stop(tdc);
+		tdc->dma_desc = NULL;
+	}
+
+	tegra_dma_sid_free(tdc);
+	vchan_get_all_descriptors(&tdc->vc, &head);
+	spin_unlock_irqrestore(&tdc->vc.lock, flags);
+
+	vchan_dma_desc_free_list(&tdc->vc, &head);
+
+	return 0;
+}
+
+static int tegra_dma_get_residual(struct tegra_dma_channel *tdc)
+{
+	unsigned long wcount = 0, status;
+	unsigned int bytes_xfer, residual;
+	struct tegra_dma_desc *dma_desc = tdc->dma_desc;
+	struct tegra_dma_sg_req *sg_req = dma_desc->sg_req;
+
+	wcount = tdc_read(tdc, TEGRA_GPCDMA_CHAN_XFER_COUNT);
+
+	/*
+	 * Set wcount = 0 if EOC bit is set. The transfer would have
+	 * already completed and the CHAN_XFER_COUNT could have updated
+	 * for the next transfer, specifically in case of cyclic transfers.
+	 */
+	status = tdc_read(tdc, TEGRA_GPCDMA_CHAN_STATUS);
+	if (status & TEGRA_GPCDMA_STATUS_ISE_EOC)
+		wcount = 0;
+
+	bytes_xfer = dma_desc->bytes_xfer +
+		     sg_req[dma_desc->sg_idx - 1].len - (wcount * 4);
+
+	residual = dma_desc->bytes_req - (bytes_xfer % dma_desc->bytes_req);
+
+	return residual;
+}
+
+static enum dma_status tegra_dma_tx_status(struct dma_chan *dc,
+					   dma_cookie_t cookie,
+					   struct dma_tx_state *txstate)
+{
+	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
+	struct tegra_dma_desc *dma_desc;
+	struct virt_dma_desc *vd;
+	unsigned int residual;
+	unsigned long flags;
+	enum dma_status ret;
+
+	ret = dma_cookie_status(dc, cookie, txstate);
+	if (ret == DMA_COMPLETE)
+		return ret;
+
+	spin_lock_irqsave(&tdc->vc.lock, flags);
+	vd = vchan_find_desc(&tdc->vc, cookie);
+	if (vd) {
+		dma_desc = vd_to_tegra_dma_desc(vd);
+		residual = dma_desc->bytes_req;
+		dma_set_residue(txstate, residual);
+	} else if (tdc->dma_desc && tdc->dma_desc->vd.tx.cookie == cookie) {
+		residual =  tegra_dma_get_residual(tdc);
+		dma_set_residue(txstate, residual);
+	} else {
+		dev_err(tdc2dev(tdc), "cookie %d is not found\n", cookie);
+	}
+	spin_unlock_irqrestore(&tdc->vc.lock, flags);
+
+	return ret;
+}
+
+static inline int get_bus_width(struct tegra_dma_channel *tdc,
+				enum dma_slave_buswidth slave_bw)
+{
+	switch (slave_bw) {
+	case DMA_SLAVE_BUSWIDTH_1_BYTE:
+		return TEGRA_GPCDMA_MMIOSEQ_BUS_WIDTH_8;
+	case DMA_SLAVE_BUSWIDTH_2_BYTES:
+		return TEGRA_GPCDMA_MMIOSEQ_BUS_WIDTH_16;
+	case DMA_SLAVE_BUSWIDTH_4_BYTES:
+		return TEGRA_GPCDMA_MMIOSEQ_BUS_WIDTH_32;
+	default:
+		dev_err(tdc2dev(tdc), "given slave bus width is not supported\n");
+		return -EINVAL;
+	}
+}
+
+static unsigned int get_burst_size(struct tegra_dma_channel *tdc,
+				   u32 burst_size, enum dma_slave_buswidth slave_bw,
+				   int len)
+{
+	unsigned int burst_mmio_width, burst_byte;
+
+	/*
+	 * burst_size from client is in terms of the bus_width.
+	 * convert that into words.
+	 * If burst_size is not specified from client, then use
+	 * len to calculate the optimum burst size
+	 */
+	burst_byte = burst_size ? burst_size * slave_bw : len;
+	burst_mmio_width = burst_byte / 4;
+
+	if (burst_mmio_width < TEGRA_GPCDMA_MMIOSEQ_BURST_MIN)
+		return 0;
+
+	burst_mmio_width = min(burst_mmio_width, TEGRA_GPCDMA_MMIOSEQ_BURST_MAX);
+
+	return TEGRA_GPCDMA_MMIOSEQ_BURST(burst_mmio_width);
+}
+
+static int get_transfer_param(struct tegra_dma_channel *tdc,
+			      enum dma_transfer_direction direction,
+			      unsigned long *apb_addr,
+			      unsigned long *mmio_seq,
+			      unsigned long *csr,
+			      unsigned int *burst_size,
+			      enum dma_slave_buswidth *slave_bw)
+{
+	switch (direction) {
+	case DMA_MEM_TO_DEV:
+		*apb_addr = tdc->dma_sconfig.dst_addr;
+		*mmio_seq = get_bus_width(tdc, tdc->dma_sconfig.dst_addr_width);
+		*burst_size = tdc->dma_sconfig.dst_maxburst;
+		*slave_bw = tdc->dma_sconfig.dst_addr_width;
+		*csr = TEGRA_GPCDMA_CSR_DMA_MEM2IO_FC;
+		return 0;
+	case DMA_DEV_TO_MEM:
+		*apb_addr = tdc->dma_sconfig.src_addr;
+		*mmio_seq = get_bus_width(tdc, tdc->dma_sconfig.src_addr_width);
+		*burst_size = tdc->dma_sconfig.src_maxburst;
+		*slave_bw = tdc->dma_sconfig.src_addr_width;
+		*csr = TEGRA_GPCDMA_CSR_DMA_IO2MEM_FC;
+		return 0;
+	case DMA_MEM_TO_MEM:
+		*burst_size = tdc->dma_sconfig.src_addr_width;
+		*csr = TEGRA_GPCDMA_CSR_DMA_MEM2MEM;
+		return 0;
+	default:
+		dev_err(tdc2dev(tdc), "DMA direction is not supported\n");
+	}
+
+	return -EINVAL;
+}
+
+static struct dma_async_tx_descriptor *
+tegra_dma_prep_dma_memset(struct dma_chan *dc, dma_addr_t dest, int value,
+			  size_t len, unsigned long flags)
+{
+	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
+	unsigned int max_dma_count = tdc->tdma->chip_data->max_dma_count;
+	struct tegra_dma_sg_req *sg_req;
+	struct tegra_dma_desc *dma_desc;
+	unsigned long csr, mc_seq;
+
+	if ((len & 3) || (dest & 3) || len > max_dma_count) {
+		dev_err(tdc2dev(tdc),
+			"DMA length/memory address is not supported\n");
+		return NULL;
+	}
+
+	/* Set dma mode to fixed pattern */
+	csr = TEGRA_GPCDMA_CSR_DMA_FIXED_PAT;
+	/* Enable once or continuous mode */
+	csr |= TEGRA_GPCDMA_CSR_ONCE;
+	/* Enable IRQ mask */
+	csr |= TEGRA_GPCDMA_CSR_IRQ_MASK;
+	/* Enable the dma interrupt */
+	if (flags & DMA_PREP_INTERRUPT)
+		csr |= TEGRA_GPCDMA_CSR_IE_EOC;
+	/* Configure default priority weight for the channel */
+	csr |= FIELD_PREP(TEGRA_GPCDMA_CSR_WEIGHT, 1);
+
+	mc_seq =  tdc_read(tdc, TEGRA_GPCDMA_CHAN_MCSEQ);
+	/* retain stream-id and clean rest */
+	mc_seq &= TEGRA_GPCDMA_MCSEQ_STREAM_ID0_MASK;
+
+	/* Set the address wrapping */
+	mc_seq |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_WRAP0,
+						TEGRA_GPCDMA_MCSEQ_WRAP_NONE);
+	mc_seq |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_WRAP1,
+						TEGRA_GPCDMA_MCSEQ_WRAP_NONE);
+
+	/* Program outstanding MC requests */
+	mc_seq |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_REQ_COUNT, 1);
+	/* Set burst size */
+	mc_seq |= TEGRA_GPCDMA_MCSEQ_BURST_16;
+
+	dma_desc = kzalloc(struct_size(dma_desc, sg_req, 1), GFP_NOWAIT);
+	if (!dma_desc)
+		return NULL;
+
+	dma_desc->bytes_req = len;
+	dma_desc->sg_count = 1;
+	sg_req = dma_desc->sg_req;
+
+	sg_req[0].ch_regs.src_ptr = 0;
+	sg_req[0].ch_regs.dst_ptr = dest;
+	sg_req[0].ch_regs.high_addr_ptr =
+			FIELD_PREP(TEGRA_GPCDMA_HIGH_ADDR_DST_PTR, (dest >> 32));
+	sg_req[0].ch_regs.fixed_pattern = value;
+	/* Word count reg takes value as (N +1) words */
+	sg_req[0].ch_regs.wcount = ((len - 4) >> 2);
+	sg_req[0].ch_regs.csr = csr;
+	sg_req[0].ch_regs.mmio_seq = 0;
+	sg_req[0].ch_regs.mc_seq = mc_seq;
+	sg_req[0].len = len;
+
+	dma_desc->cyclic = false;
+	return vchan_tx_prep(&tdc->vc, &dma_desc->vd, flags);
+}
+
+static struct dma_async_tx_descriptor *
+tegra_dma_prep_dma_memcpy(struct dma_chan *dc, dma_addr_t dest,
+			  dma_addr_t src, size_t len, unsigned long flags)
+{
+	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
+	unsigned int max_dma_count = tdc->tdma->chip_data->max_dma_count;
+	struct tegra_dma_sg_req *sg_req;
+	struct tegra_dma_desc *dma_desc;
+	unsigned long csr, mc_seq;
+
+	if ((len & 3) || (src & 3) || (dest & 3) || len > max_dma_count) {
+		dev_err(tdc2dev(tdc),
+			"DMA length/memory address is not supported\n");
+		return NULL;
+	}
+
+	/* Set dma mode to memory to memory transfer */
+	csr = TEGRA_GPCDMA_CSR_DMA_MEM2MEM;
+	/* Enable once or continuous mode */
+	csr |= TEGRA_GPCDMA_CSR_ONCE;
+	/* Enable IRQ mask */
+	csr |= TEGRA_GPCDMA_CSR_IRQ_MASK;
+	/* Enable the dma interrupt */
+	if (flags & DMA_PREP_INTERRUPT)
+		csr |= TEGRA_GPCDMA_CSR_IE_EOC;
+	/* Configure default priority weight for the channel */
+	csr |= FIELD_PREP(TEGRA_GPCDMA_CSR_WEIGHT, 1);
+
+	mc_seq =  tdc_read(tdc, TEGRA_GPCDMA_CHAN_MCSEQ);
+	/* retain stream-id and clean rest */
+	mc_seq &= (TEGRA_GPCDMA_MCSEQ_STREAM_ID0_MASK) |
+		  (TEGRA_GPCDMA_MCSEQ_STREAM_ID1_MASK);
+
+	/* Set the address wrapping */
+	mc_seq |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_WRAP0,
+			     TEGRA_GPCDMA_MCSEQ_WRAP_NONE);
+	mc_seq |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_WRAP1,
+			     TEGRA_GPCDMA_MCSEQ_WRAP_NONE);
+
+	/* Program outstanding MC requests */
+	mc_seq |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_REQ_COUNT, 1);
+	/* Set burst size */
+	mc_seq |= TEGRA_GPCDMA_MCSEQ_BURST_16;
+
+	dma_desc = kzalloc(struct_size(dma_desc, sg_req, 1), GFP_NOWAIT);
+	if (!dma_desc)
+		return NULL;
+
+	dma_desc->bytes_req = len;
+	dma_desc->sg_count = 1;
+	sg_req = dma_desc->sg_req;
+
+	sg_req[0].ch_regs.src_ptr = src;
+	sg_req[0].ch_regs.dst_ptr = dest;
+	sg_req[0].ch_regs.high_addr_ptr =
+		FIELD_PREP(TEGRA_GPCDMA_HIGH_ADDR_SRC_PTR, (src >> 32));
+	sg_req[0].ch_regs.high_addr_ptr |=
+		FIELD_PREP(TEGRA_GPCDMA_HIGH_ADDR_DST_PTR, (dest >> 32));
+	/* Word count reg takes value as (N +1) words */
+	sg_req[0].ch_regs.wcount = ((len - 4) >> 2);
+	sg_req[0].ch_regs.csr = csr;
+	sg_req[0].ch_regs.mmio_seq = 0;
+	sg_req[0].ch_regs.mc_seq = mc_seq;
+	sg_req[0].len = len;
+
+	dma_desc->cyclic = false;
+	return vchan_tx_prep(&tdc->vc, &dma_desc->vd, flags);
+}
+
+static struct dma_async_tx_descriptor *
+tegra_dma_prep_slave_sg(struct dma_chan *dc, struct scatterlist *sgl,
+			unsigned int sg_len, enum dma_transfer_direction direction,
+			unsigned long flags, void *context)
+{
+	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
+	unsigned int max_dma_count = tdc->tdma->chip_data->max_dma_count;
+	unsigned long csr, mc_seq, apb_ptr = 0, mmio_seq = 0;
+	enum dma_slave_buswidth slave_bw;
+	struct tegra_dma_sg_req *sg_req;
+	struct tegra_dma_desc *dma_desc;
+	struct scatterlist *sg;
+	u32 burst_size;
+	unsigned int i;
+	int ret;
+
+	if (!tdc->config_init) {
+		dev_err(tdc2dev(tdc), "DMA channel is not configured\n");
+		return NULL;
+	}
+	if (sg_len < 1) {
+		dev_err(tdc2dev(tdc), "Invalid segment length %d\n", sg_len);
+		return NULL;
+	}
+
+	ret = tegra_dma_sid_reserve(tdc, direction);
+	if (ret)
+		return NULL;
+
+	ret = get_transfer_param(tdc, direction, &apb_ptr, &mmio_seq, &csr,
+				 &burst_size, &slave_bw);
+	if (ret < 0)
+		return NULL;
+
+	/* Enable once or continuous mode */
+	csr |= TEGRA_GPCDMA_CSR_ONCE;
+	/* Program the slave id in requestor select */
+	csr |= FIELD_PREP(TEGRA_GPCDMA_CSR_REQ_SEL_MASK, tdc->slave_id);
+	/* Enable IRQ mask */
+	csr |= TEGRA_GPCDMA_CSR_IRQ_MASK;
+	/* Configure default priority weight for the channel*/
+	csr |= FIELD_PREP(TEGRA_GPCDMA_CSR_WEIGHT, 1);
+
+	/* Enable the dma interrupt */
+	if (flags & DMA_PREP_INTERRUPT)
+		csr |= TEGRA_GPCDMA_CSR_IE_EOC;
+
+	mc_seq =  tdc_read(tdc, TEGRA_GPCDMA_CHAN_MCSEQ);
+	/* retain stream-id and clean rest */
+	mc_seq &= TEGRA_GPCDMA_MCSEQ_STREAM_ID0_MASK;
+
+	/* Set the address wrapping on both MC and MMIO side */
+
+	mc_seq |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_WRAP0,
+			     TEGRA_GPCDMA_MCSEQ_WRAP_NONE);
+	mc_seq |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_WRAP1,
+			     TEGRA_GPCDMA_MCSEQ_WRAP_NONE);
+	mmio_seq |= FIELD_PREP(TEGRA_GPCDMA_MMIOSEQ_WRAP_WORD, 1);
+
+	/* Program 2 MC outstanding requests by default. */
+	mc_seq |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_REQ_COUNT, 1);
+
+	/* Setting MC burst size depending on MMIO burst size */
+	if (burst_size == 64)
+		mc_seq |= TEGRA_GPCDMA_MCSEQ_BURST_16;
+	else
+		mc_seq |= TEGRA_GPCDMA_MCSEQ_BURST_2;
+
+	dma_desc = kzalloc(struct_size(dma_desc, sg_req, 1), GFP_NOWAIT);
+	if (!dma_desc)
+		return NULL;
+
+	dma_desc->sg_count = sg_len;
+	sg_req = dma_desc->sg_req;
+
+	/* Make transfer requests */
+	for_each_sg(sgl, sg, sg_len, i) {
+		u32 len;
+		dma_addr_t mem;
+
+		mem = sg_dma_address(sg);
+		len = sg_dma_len(sg);
+
+		if ((len & 3) || (mem & 3) || len > max_dma_count) {
+			dev_err(tdc2dev(tdc),
+				"DMA length/memory address is not supported\n");
+			kfree(dma_desc);
+			return NULL;
+		}
+
+		mmio_seq |= get_burst_size(tdc, burst_size, slave_bw, len);
+		dma_desc->bytes_req += len;
+
+		if (direction == DMA_MEM_TO_DEV) {
+			sg_req[i].ch_regs.src_ptr = mem;
+			sg_req[i].ch_regs.dst_ptr = apb_ptr;
+			sg_req[i].ch_regs.high_addr_ptr =
+				FIELD_PREP(TEGRA_GPCDMA_HIGH_ADDR_SRC_PTR, (mem >> 32));
+		} else if (direction == DMA_DEV_TO_MEM) {
+			sg_req[i].ch_regs.src_ptr = apb_ptr;
+			sg_req[i].ch_regs.dst_ptr = mem;
+			sg_req[i].ch_regs.high_addr_ptr =
+				FIELD_PREP(TEGRA_GPCDMA_HIGH_ADDR_DST_PTR, (mem >> 32));
+		}
+
+		/*
+		 * Word count register takes input in words. Writing a value
+		 * of N into word count register means a req of (N+1) words.
+		 */
+		sg_req[i].ch_regs.wcount = ((len - 4) >> 2);
+		sg_req[i].ch_regs.csr = csr;
+		sg_req[i].ch_regs.mmio_seq = mmio_seq;
+		sg_req[i].ch_regs.mc_seq = mc_seq;
+		sg_req[i].len = len;
+	}
+
+	dma_desc->cyclic = false;
+	return vchan_tx_prep(&tdc->vc, &dma_desc->vd, flags);
+}
+
+static struct dma_async_tx_descriptor *
+tegra_dma_prep_dma_cyclic(struct dma_chan *dc, dma_addr_t buf_addr, size_t buf_len,
+			  size_t period_len, enum dma_transfer_direction direction,
+			  unsigned long flags)
+{
+	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
+	unsigned int max_dma_count = tdc->tdma->chip_data->max_dma_count;
+	struct tegra_dma_desc *dma_desc;
+	struct tegra_dma_sg_req *sg_req;
+	unsigned long csr, mc_seq, apb_ptr = 0, mmio_seq = 0;
+	unsigned int len, period_count, i;
+	dma_addr_t mem = buf_addr;
+	u32 burst_size;
+	enum dma_slave_buswidth slave_bw;
+	int ret;
+
+	if (!buf_len || !period_len) {
+		dev_err(tdc2dev(tdc), "Invalid buffer/period len\n");
+		return NULL;
+	}
+
+	if (!tdc->config_init) {
+		dev_err(tdc2dev(tdc), "DMA slave is not configured\n");
+		return NULL;
+	}
+
+	ret = tegra_dma_sid_reserve(tdc, direction);
+	if (ret)
+		return NULL;
+
+	/*
+	 * We only support cycle transfer when buf_len is multiple of
+	 * period_len.
+	 */
+	if (buf_len % period_len) {
+		dev_err(tdc2dev(tdc), "buf_len is not multiple of period_len\n");
+		return NULL;
+	}
+
+	len = period_len;
+	if ((len & 3) || (buf_addr & 3) || len > max_dma_count) {
+		dev_err(tdc2dev(tdc), "Req len/mem address is not correct\n");
+		return NULL;
+	}
+
+	ret = get_transfer_param(tdc, direction, &apb_ptr, &mmio_seq, &csr,
+				 &burst_size, &slave_bw);
+	if (ret < 0)
+		return NULL;
+
+	/* Enable once or continuous mode */
+	csr &= ~TEGRA_GPCDMA_CSR_ONCE;
+	/* Program the slave id in requestor select */
+	csr |= FIELD_PREP(TEGRA_GPCDMA_CSR_REQ_SEL_MASK, tdc->slave_id);
+	/* Enable IRQ mask */
+	csr |= TEGRA_GPCDMA_CSR_IRQ_MASK;
+	/* Configure default priority weight for the channel*/
+	csr |= FIELD_PREP(TEGRA_GPCDMA_CSR_WEIGHT, 1);
+
+	/* Enable the dma interrupt */
+	if (flags & DMA_PREP_INTERRUPT)
+		csr |= TEGRA_GPCDMA_CSR_IE_EOC;
+
+	mmio_seq |= FIELD_PREP(TEGRA_GPCDMA_MMIOSEQ_WRAP_WORD, 1);
+
+	mc_seq =  tdc_read(tdc, TEGRA_GPCDMA_CHAN_MCSEQ);
+	/* retain stream-id and clean rest */
+	mc_seq &= TEGRA_GPCDMA_MCSEQ_STREAM_ID0_MASK;
+
+	/* Set the address wrapping on both MC and MMIO side */
+	mc_seq |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_WRAP0,
+			     TEGRA_GPCDMA_MCSEQ_WRAP_NONE);
+	mc_seq |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_WRAP1,
+			     TEGRA_GPCDMA_MCSEQ_WRAP_NONE);
+
+	/* Program 2 MC outstanding requests by default. */
+	mc_seq |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_REQ_COUNT, 1);
+	/* Setting MC burst size depending on MMIO burst size */
+	if (burst_size == 64)
+		mc_seq |= TEGRA_GPCDMA_MCSEQ_BURST_16;
+	else
+		mc_seq |= TEGRA_GPCDMA_MCSEQ_BURST_2;
+
+	period_count = buf_len / period_len;
+	dma_desc = kzalloc(struct_size(dma_desc, sg_req, period_count),
+			   GFP_NOWAIT);
+	if (!dma_desc)
+		return NULL;
+
+	dma_desc->bytes_req = buf_len;
+	dma_desc->sg_count = period_count;
+
+	/* Split transfer equal to period size */
+	for (i = 0; i < period_count; i++) {
+		mmio_seq |= get_burst_size(tdc, burst_size, slave_bw, len);
+		if (direction == DMA_MEM_TO_DEV) {
+			sg_req[i].ch_regs.src_ptr = mem;
+			sg_req[i].ch_regs.dst_ptr = apb_ptr;
+			sg_req[i].ch_regs.high_addr_ptr =
+				FIELD_PREP(TEGRA_GPCDMA_HIGH_ADDR_SRC_PTR, (mem >> 32));
+		} else if (direction == DMA_DEV_TO_MEM) {
+			sg_req[i].ch_regs.src_ptr = apb_ptr;
+			sg_req[i].ch_regs.dst_ptr = mem;
+			sg_req[i].ch_regs.high_addr_ptr =
+				FIELD_PREP(TEGRA_GPCDMA_HIGH_ADDR_DST_PTR, (mem >> 32));
+		}
+		/*
+		 * Word count register takes input in words. Writing a value
+		 * of N into word count register means a req of (N+1) words.
+		 */
+		sg_req[i].ch_regs.wcount = ((len - 4) >> 2);
+		sg_req[i].ch_regs.csr = csr;
+		sg_req[i].ch_regs.mmio_seq = mmio_seq;
+		sg_req[i].ch_regs.mc_seq = mc_seq;
+		sg_req[i].len = len;
+
+		mem += len;
+	}
+
+	dma_desc->cyclic = true;
+
+	return vchan_tx_prep(&tdc->vc, &dma_desc->vd, flags);
+}
+
+static int tegra_dma_alloc_chan_resources(struct dma_chan *dc)
+{
+	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
+	int ret;
+
+	ret = request_irq(tdc->irq, tegra_dma_isr, 0, tdc->name, tdc);
+	if (ret) {
+		dev_err(tdc2dev(tdc), "request_irq failed for %s\n", tdc->name);
+		return ret;
+	}
+
+	dma_cookie_init(&tdc->vc.chan);
+	tdc->config_init = false;
+	return 0;
+}
+
+static void tegra_dma_chan_synchronize(struct dma_chan *dc)
+{
+	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
+
+	synchronize_irq(tdc->irq);
+	vchan_synchronize(&tdc->vc);
+}
+
+static void tegra_dma_free_chan_resources(struct dma_chan *dc)
+{
+	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
+
+	dev_dbg(tdc2dev(tdc), "Freeing channel %d\n", tdc->id);
+
+	tegra_dma_terminate_all(dc);
+	synchronize_irq(tdc->irq);
+
+	tasklet_kill(&tdc->vc.task);
+	tdc->config_init = false;
+	tdc->slave_id = -1;
+	tdc->sid_dir = DMA_TRANS_NONE;
+	free_irq(tdc->irq, tdc);
+
+	vchan_free_chan_resources(&tdc->vc);
+}
+
+static struct dma_chan *tegra_dma_of_xlate(struct of_phandle_args *dma_spec,
+					   struct of_dma *ofdma)
+{
+	struct tegra_dma *tdma = ofdma->of_dma_data;
+	struct tegra_dma_channel *tdc;
+	struct dma_chan *chan;
+
+	chan = dma_get_any_slave_channel(&tdma->dma_dev);
+	if (!chan)
+		return NULL;
+
+	tdc = to_tegra_dma_chan(chan);
+	tdc->slave_id = dma_spec->args[0];
+
+	return chan;
+}
+
+static const struct tegra_dma_chip_data tegra186_dma_chip_data = {
+	.nr_channels = 31,
+	.channel_reg_size = SZ_64K,
+	.max_dma_count = SZ_1G,
+	.hw_support_pause = false,
+};
+
+static const struct tegra_dma_chip_data tegra194_dma_chip_data = {
+	.nr_channels = 31,
+	.channel_reg_size = SZ_64K,
+	.max_dma_count = SZ_1G,
+	.hw_support_pause = true,
+};
+
+static const struct of_device_id tegra_dma_of_match[] = {
+	{
+		.compatible = "nvidia,tegra186-gpcdma",
+		.data = &tegra186_dma_chip_data,
+	}, {
+		.compatible = "nvidia,tegra194-gpcdma",
+		.data = &tegra194_dma_chip_data,
+	}, {
+	},
+};
+MODULE_DEVICE_TABLE(of, tegra_dma_of_match);
+
+static int tegra_dma_program_sid(struct tegra_dma_channel *tdc,
+				 int chan, int stream_id)
+{
+	unsigned int reg_val =  tdc_read(tdc, TEGRA_GPCDMA_CHAN_MCSEQ);
+
+	reg_val &= ~(TEGRA_GPCDMA_MCSEQ_STREAM_ID0_MASK);
+	reg_val &= ~(TEGRA_GPCDMA_MCSEQ_STREAM_ID1_MASK);
+
+	reg_val |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_STREAM_ID0_MASK, stream_id);
+	reg_val |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_STREAM_ID1_MASK, stream_id);
+
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_MCSEQ, reg_val);
+	return 0;
+}
+
+static int tegra_dma_probe(struct platform_device *pdev)
+{
+	const struct tegra_dma_chip_data *cdata = NULL;
+	struct iommu_fwspec *iommu_spec;
+	unsigned int stream_id, i;
+	struct tegra_dma *tdma;
+	struct resource	*res;
+	int ret;
+
+	cdata = of_device_get_match_data(&pdev->dev);
+
+	tdma = devm_kzalloc(&pdev->dev, sizeof(*tdma) + cdata->nr_channels *
+			sizeof(struct tegra_dma_channel), GFP_KERNEL);
+	if (!tdma)
+		return -ENOMEM;
+
+	tdma->dev = &pdev->dev;
+	tdma->chip_data = cdata;
+	platform_set_drvdata(pdev, tdma);
+
+	tdma->base_addr = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(tdma->base_addr))
+		return PTR_ERR(tdma->base_addr);
+
+	tdma->rst = devm_reset_control_get_exclusive(&pdev->dev, "gpcdma");
+	if (IS_ERR(tdma->rst)) {
+		return dev_err_probe(&pdev->dev, PTR_ERR(tdma->rst),
+			      "Missing controller reset\n");
+	}
+	reset_control_reset(tdma->rst);
+
+	tdma->dma_dev.dev = &pdev->dev;
+
+	iommu_spec = dev_iommu_fwspec_get(&pdev->dev);
+	if (!iommu_spec) {
+		dev_err(&pdev->dev, "Missing iommu stream-id\n");
+		return -EINVAL;
+	}
+	stream_id = iommu_spec->ids[0] & 0xffff;
+
+	INIT_LIST_HEAD(&tdma->dma_dev.channels);
+	for (i = 0; i < cdata->nr_channels; i++) {
+		struct tegra_dma_channel *tdc = &tdma->channels[i];
+
+		tdc->chan_base_offset = TEGRA_GPCDMA_CHANNEL_BASE_ADD_OFFSET +
+					i * cdata->channel_reg_size;
+		res = platform_get_resource(pdev, IORESOURCE_IRQ, i);
+		if (!res) {
+			dev_err(&pdev->dev, "No irq resource for chan %d\n", i);
+			return -EINVAL;
+		}
+		tdc->irq = res->start;
+		snprintf(tdc->name, sizeof(tdc->name), "gpcdma.%d", i);
+
+		tdc->tdma = tdma;
+		tdc->id = i;
+		tdc->slave_id = -1;
+
+		vchan_init(&tdc->vc, &tdma->dma_dev);
+		tdc->vc.desc_free = tegra_dma_desc_free;
+
+		/* program stream-id for this channel */
+		tegra_dma_program_sid(tdc, i, stream_id);
+		tdc->stream_id = stream_id;
+	}
+
+	dma_cap_set(DMA_SLAVE, tdma->dma_dev.cap_mask);
+	dma_cap_set(DMA_PRIVATE, tdma->dma_dev.cap_mask);
+	dma_cap_set(DMA_MEMCPY, tdma->dma_dev.cap_mask);
+	dma_cap_set(DMA_MEMSET, tdma->dma_dev.cap_mask);
+	dma_cap_set(DMA_CYCLIC, tdma->dma_dev.cap_mask);
+
+	/*
+	 * Only word aligned transfers are supported. Set the copy
+	 * alignment shift.
+	 */
+	tdma->dma_dev.copy_align = 2;
+	tdma->dma_dev.fill_align = 2;
+	tdma->dma_dev.device_alloc_chan_resources =
+					tegra_dma_alloc_chan_resources;
+	tdma->dma_dev.device_free_chan_resources =
+					tegra_dma_free_chan_resources;
+	tdma->dma_dev.device_prep_slave_sg = tegra_dma_prep_slave_sg;
+	tdma->dma_dev.device_prep_dma_memcpy = tegra_dma_prep_dma_memcpy;
+	tdma->dma_dev.device_prep_dma_memset = tegra_dma_prep_dma_memset;
+	tdma->dma_dev.device_prep_dma_cyclic = tegra_dma_prep_dma_cyclic;
+	tdma->dma_dev.device_config = tegra_dma_slave_config;
+	tdma->dma_dev.device_terminate_all = tegra_dma_terminate_all;
+	tdma->dma_dev.device_tx_status = tegra_dma_tx_status;
+	tdma->dma_dev.device_issue_pending = tegra_dma_issue_pending;
+	tdma->dma_dev.device_pause = tegra_dma_device_pause;
+	tdma->dma_dev.device_resume = tegra_dma_device_resume;
+	tdma->dma_dev.device_synchronize = tegra_dma_chan_synchronize;
+	tdma->dma_dev.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
+
+	ret = dma_async_device_register(&tdma->dma_dev);
+	if (ret < 0) {
+		dev_err_probe(&pdev->dev, ret,
+			      "GPC DMA driver registration failed\n");
+		return ret;
+	}
+
+	ret = of_dma_controller_register(pdev->dev.of_node,
+					 tegra_dma_of_xlate, tdma);
+	if (ret < 0) {
+		dev_err_probe(&pdev->dev, ret,
+			      "GPC DMA OF registration failed\n");
+
+		dma_async_device_unregister(&tdma->dma_dev);
+		return ret;
+	}
+
+	dev_info(&pdev->dev, "GPC DMA driver register %d channels\n",
+		 cdata->nr_channels);
+
+	return 0;
+}
+
+static int tegra_dma_remove(struct platform_device *pdev)
+{
+	struct tegra_dma *tdma = platform_get_drvdata(pdev);
+
+	of_dma_controller_free(pdev->dev.of_node);
+	dma_async_device_unregister(&tdma->dma_dev);
+
+	return 0;
+}
+
+static int __maybe_unused tegra_dma_pm_suspend(struct device *dev)
+{
+	struct tegra_dma *tdma = dev_get_drvdata(dev);
+	unsigned int i;
+
+	for (i = 0; i < tdma->chip_data->nr_channels; i++) {
+		struct tegra_dma_channel *tdc = &tdma->channels[i];
+
+		if (tdc->dma_desc) {
+			dev_err(tdma->dev, "channel %u busy\n", i);
+			return -EBUSY;
+		}
+	}
+
+	return 0;
+}
+
+static int __maybe_unused tegra_dma_pm_resume(struct device *dev)
+{
+	struct tegra_dma *tdma = dev_get_drvdata(dev);
+	unsigned int i;
+
+	reset_control_reset(tdma->rst);
+
+	for (i = 0; i < tdma->chip_data->nr_channels; i++) {
+		struct tegra_dma_channel *tdc = &tdma->channels[i];
+
+		tegra_dma_program_sid(tdc, i, tdc->stream_id);
+	}
+
+	return 0;
+}
+
+static const struct __maybe_unused dev_pm_ops tegra_dma_dev_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(tegra_dma_pm_suspend, tegra_dma_pm_resume)
+};
+
+static struct platform_driver tegra_dmac_driver = {
+	.driver = {
+		.name	= "tegra-gpcdma",
+		.pm	= &tegra_dma_dev_pm_ops,
+		.of_match_table = tegra_dma_of_match,
+	},
+	.probe		= tegra_dma_probe,
+	.remove		= tegra_dma_remove,
+};
+
+module_platform_driver(tegra_dmac_driver);
+
+MODULE_DESCRIPTION("NVIDIA Tegra GPC DMA Controller driver");
+MODULE_AUTHOR("Pavan Kunapuli <pkunapuli@nvidia.com>");
+MODULE_AUTHOR("Rajesh Gumasta <rgumasta@nvidia.com>");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4


^ permalink raw reply related	[flat|nested] 12+ messages in thread

* [PATCH v18 3/4] arm64: defconfig: tegra: Enable GPCDMA
  2022-02-01 15:26 [PATCH v18 0/4] Add NVIDIA Tegra GPC-DMA driver Akhil R
  2022-02-01 15:26 ` [PATCH v18 1/4] dt-bindings: dmaengine: Add doc for tegra gpcdma Akhil R
  2022-02-01 15:26 ` [PATCH v18 2/4] dmaengine: tegra: Add tegra gpcdma driver Akhil R
@ 2022-02-01 15:26 ` Akhil R
  2022-02-01 15:26 ` [PATCH v18 4/4] arm64: tegra: Add GPCDMA node for tegra186 and tegra194 Akhil R
  3 siblings, 0 replies; 12+ messages in thread
From: Akhil R @ 2022-02-01 15:26 UTC (permalink / raw)
  To: devicetree, dmaengine, jonathanh, kyarlagadda, ldewangan,
	linux-kernel, linux-tegra, p.zabel, rgumasta, robh+dt,
	thierry.reding, vkoul
  Cc: akhilrajeev

Enable TEGRA_GPC_DMA in defconfig for Tegra186 and Tegra196 gpc
dma controller driver

Signed-off-by: Rajesh Gumasta <rgumasta@nvidia.com>
Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
---
 arch/arm64/configs/defconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig
index ee4bd77..96a796d 100644
--- a/arch/arm64/configs/defconfig
+++ b/arch/arm64/configs/defconfig
@@ -956,6 +956,7 @@ CONFIG_MV_XOR=y
 CONFIG_MV_XOR_V2=y
 CONFIG_OWL_DMA=y
 CONFIG_PL330_DMA=y
+CONFIG_TEGRA186_GPC_DMA=m
 CONFIG_TEGRA20_APB_DMA=y
 CONFIG_TEGRA210_ADMA=m
 CONFIG_QCOM_BAM_DMA=y
-- 
2.7.4


^ permalink raw reply related	[flat|nested] 12+ messages in thread

* [PATCH v18 4/4] arm64: tegra: Add GPCDMA node for tegra186 and tegra194
  2022-02-01 15:26 [PATCH v18 0/4] Add NVIDIA Tegra GPC-DMA driver Akhil R
                   ` (2 preceding siblings ...)
  2022-02-01 15:26 ` [PATCH v18 3/4] arm64: defconfig: tegra: Enable GPCDMA Akhil R
@ 2022-02-01 15:26 ` Akhil R
  3 siblings, 0 replies; 12+ messages in thread
From: Akhil R @ 2022-02-01 15:26 UTC (permalink / raw)
  To: devicetree, dmaengine, jonathanh, kyarlagadda, ldewangan,
	linux-kernel, linux-tegra, p.zabel, rgumasta, robh+dt,
	thierry.reding, vkoul
  Cc: akhilrajeev

Add device tree node for GPCDMA controller on Tegra186 target
and Tegra194 target.

Signed-off-by: Rajesh Gumasta <rgumasta@nvidia.com>
Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
---
 arch/arm64/boot/dts/nvidia/tegra186.dtsi | 42 +++++++++++++++++++++++++++++++
 arch/arm64/boot/dts/nvidia/tegra194.dtsi | 43 ++++++++++++++++++++++++++++++++
 2 files changed, 85 insertions(+)

diff --git a/arch/arm64/boot/dts/nvidia/tegra186.dtsi b/arch/arm64/boot/dts/nvidia/tegra186.dtsi
index c91afff..899d7b1 100644
--- a/arch/arm64/boot/dts/nvidia/tegra186.dtsi
+++ b/arch/arm64/boot/dts/nvidia/tegra186.dtsi
@@ -73,6 +73,48 @@
 		snps,rxpbl = <8>;
 	};
 
+	gpcdma: dma-controller@2600000 {
+		compatible = "nvidia,tegra186-gpcdma";
+		reg = <0x0 0x2600000 0x0 0x210000>;
+		resets = <&bpmp TEGRA186_RESET_GPCDMA>;
+		reset-names = "gpcdma";
+		interrupts = <GIC_SPI 76 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 77 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 78 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 79 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 80 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 81 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 82 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 83 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 84 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 85 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 86 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 87 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 88 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 89 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 90 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 91 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 92 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 93 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 94 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 95 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 96 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 97 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 98 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 99 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 100 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 101 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 102 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 103 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 104 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 105 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 106 IRQ_TYPE_LEVEL_HIGH>;
+		#dma-cells = <1>;
+		iommus = <&smmu TEGRA186_SID_GPCDMA_0>;
+		dma-coherent;
+		status = "okay";
+	};
+
 	aconnect@2900000 {
 		compatible = "nvidia,tegra186-aconnect",
 			     "nvidia,tegra210-aconnect";
diff --git a/arch/arm64/boot/dts/nvidia/tegra194.dtsi b/arch/arm64/boot/dts/nvidia/tegra194.dtsi
index 2d48c37..8b58f5cb 100644
--- a/arch/arm64/boot/dts/nvidia/tegra194.dtsi
+++ b/arch/arm64/boot/dts/nvidia/tegra194.dtsi
@@ -115,6 +115,49 @@
 			snps,rxpbl = <8>;
 		};
 
+		gpcdma: dma-controller@2600000 {
+			compatible = "nvidia,tegra194-gpcdma",
+				     "nvidia,tegra186-gpcdma";
+			reg = <0x2600000 0x210000>;
+			resets = <&bpmp TEGRA194_RESET_GPCDMA>;
+			reset-names = "gpcdma";
+			interrupts = <GIC_SPI 76 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 77 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 78 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 79 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 80 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 81 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 82 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 83 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 84 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 85 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 86 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 87 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 88 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 89 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 90 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 91 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 92 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 93 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 94 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 95 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 96 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 97 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 98 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 99 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 100 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 101 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 102 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 103 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 104 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 105 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 106 IRQ_TYPE_LEVEL_HIGH>;
+			#dma-cells = <1>;
+			iommus = <&smmu TEGRA194_SID_GPCDMA_0>;
+			dma-coherent;
+			status = "okay";
+		};
+
 		aconnect@2900000 {
 			compatible = "nvidia,tegra194-aconnect",
 				     "nvidia,tegra210-aconnect";
-- 
2.7.4


^ permalink raw reply related	[flat|nested] 12+ messages in thread

* Re: [PATCH v18 2/4] dmaengine: tegra: Add tegra gpcdma driver
  2022-02-01 15:26 ` [PATCH v18 2/4] dmaengine: tegra: Add tegra gpcdma driver Akhil R
@ 2022-02-02 15:45   ` Dmitry Osipenko
  2022-02-03  3:44     ` Akhil R
  2022-02-03  0:18   ` kernel test robot
  1 sibling, 1 reply; 12+ messages in thread
From: Dmitry Osipenko @ 2022-02-02 15:45 UTC (permalink / raw)
  To: Akhil R, devicetree, dmaengine, jonathanh, kyarlagadda,
	ldewangan, linux-kernel, linux-tegra, p.zabel, rgumasta, robh+dt,
	thierry.reding, vkoul
  Cc: Pavan Kunapuli

....
> +static int tegra_dma_pause(struct tegra_dma_channel *tdc)
> +{
> +	int ret;
> +	u32 val;
> +
> +	val = tdc_read(tdc, TEGRA_GPCDMA_CHAN_CSRE);
> +	val |= TEGRA_GPCDMA_CHAN_CSRE_PAUSE;
> +	tdc_write(tdc, TEGRA_GPCDMA_CHAN_CSRE, val);
> +
> +	/* Wait until busy bit is de-asserted */
> +	ret = readl_relaxed_poll_timeout_atomic(tdc->tdma->base_addr +
> +			tdc->chan_base_offset + TEGRA_GPCDMA_CHAN_STATUS,
> +			val,
> +			!(val & TEGRA_GPCDMA_STATUS_BUSY),
> +			TEGRA_GPCDMA_BURST_COMPLETE_TIME,
> +			TEGRA_GPCDMA_BURST_COMPLETION_TIMEOUT);
> +
> +	return ret;
> +}
> +
> +static int tegra_dma_device_pause(struct dma_chan *dc)
> +{
> +	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
> +	unsigned long flags;
> +	int ret = 0;
> +
> +	if (!tdc->tdma->chip_data->hw_support_pause)
> +		return -ENOSYS;
> +
> +	spin_lock_irqsave(&tdc->vc.lock, flags);
> +	ret = tegra_dma_pause(tdc);
> +	if (ret)
> +		dev_err(tdc2dev(tdc), "DMA pause timed out\n");

Why error message shouldn't be printed by tegra_dma_terminate_all()?

The error message should be placed inside of tegra_dma_pause().

...
> +static int tegra_dma_stop_client(struct tegra_dma_channel *tdc)
> +{
> +	int ret;
> +	unsigned long status;
> +	u32 csr = tdc_read(tdc, TEGRA_GPCDMA_CHAN_CSR);
> +
> +	/*
> +	 * Change the client associated with the DMA channel
> +	 * to stop DMA engine from starting any more bursts for
> +	 * the given client and wait for in flight bursts to complete
> +	 */
> +	csr &= ~(TEGRA_GPCDMA_CSR_REQ_SEL_MASK);
> +	csr |= TEGRA_GPCDMA_CSR_REQ_SEL_UNUSED;
> +	tdc_write(tdc, TEGRA_GPCDMA_CHAN_CSR, csr);
> +
> +	/* Wait for in flight data transfer to finish */
> +	udelay(TEGRA_GPCDMA_BURST_COMPLETE_TIME);
> +
> +	/* If TX/RX path is still active wait till it becomes
> +	 * inactive
> +	 */
> +
> +	ret = readl_relaxed_poll_timeout_atomic(tdc->tdma->base_addr +
> +				tdc->chan_base_offset +
> +				TEGRA_GPCDMA_CHAN_STATUS,
> +				status,
> +				!(status & (TEGRA_GPCDMA_STATUS_CHANNEL_TX |
> +				TEGRA_GPCDMA_STATUS_CHANNEL_RX)),
> +				5,
> +				TEGRA_GPCDMA_BURST_COMPLETION_TIMEOUT);
> +	if (ret) {
> +		dev_err(tdc2dev(tdc), "Timeout waiting for DMA burst completion!\n");
> +		tegra_dma_dump_chan_regs(tdc);
> +	}
> +
> +	return ret;
> +}
> +
> +static int tegra_dma_terminate_all(struct dma_chan *dc)
> +{
> +	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
> +	unsigned long flags;
> +	LIST_HEAD(head);
> +	int err;
> +
> +	spin_lock_irqsave(&tdc->vc.lock, flags);
> +
> +	if (tdc->dma_desc) {
> +		err = tdc->tdma->chip_data->hw_support_pause ?
> +		      tegra_dma_pause(tdc) :
> +		      tegra_dma_stop_client(tdc);

The canonical coding style is:

if (tdc->tdma->chip_data->hw_support_pause)
	err = tegra_dma_pause(tdc);
else
	err = tegra_dma_stop_client(tdc);


But why do you need to pause at all here and can't use
tegra_dma_stop_client() even if pause is supported?

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH v18 2/4] dmaengine: tegra: Add tegra gpcdma driver
  2022-02-01 15:26 ` [PATCH v18 2/4] dmaengine: tegra: Add tegra gpcdma driver Akhil R
  2022-02-02 15:45   ` Dmitry Osipenko
@ 2022-02-03  0:18   ` kernel test robot
  1 sibling, 0 replies; 12+ messages in thread
From: kernel test robot @ 2022-02-03  0:18 UTC (permalink / raw)
  To: kbuild-all

[-- Attachment #1: Type: text/plain, Size: 15577 bytes --]

Hi Akhil,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on vkoul-dmaengine/next]
[also build test WARNING on robh/for-next arm64/for-next/core v5.17-rc2 next-20220202]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Akhil-R/Add-NVIDIA-Tegra-GPC-DMA-driver/20220201-232959
base:   https://git.kernel.org/pub/scm/linux/kernel/git/vkoul/dmaengine.git next
config: nds32-allyesconfig (https://download.01.org/0day-ci/archive/20220203/202202030717.azJOwFpH-lkp(a)intel.com/config)
compiler: nds32le-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/fb896830918f8dc1c138094bb4c5cc5e19d149c9
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Akhil-R/Add-NVIDIA-Tegra-GPC-DMA-driver/20220201-232959
        git checkout fb896830918f8dc1c138094bb4c5cc5e19d149c9
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=nds32 SHELL=/bin/bash drivers/dma/ drivers/iommu/ drivers/mfd/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   In file included from <command-line>:
   drivers/dma/tegra186-gpc-dma.c: In function 'tegra_dma_prep_dma_memset':
>> drivers/dma/tegra186-gpc-dma.c:896:74: warning: right shift count >= width of type [-Wshift-count-overflow]
     896 |                         FIELD_PREP(TEGRA_GPCDMA_HIGH_ADDR_DST_PTR, (dest >> 32));
         |                                                                          ^~
   include/linux/compiler_types.h:315:23: note: in definition of macro '__compiletime_assert'
     315 |                 if (!(condition))                                       \
         |                       ^~~~~~~~~
   include/linux/compiler_types.h:335:9: note: in expansion of macro '_compiletime_assert'
     335 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
         |         ^~~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
      39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
         |                                     ^~~~~~~~~~~~~~~~~~
   include/linux/bitfield.h:49:17: note: in expansion of macro 'BUILD_BUG_ON_MSG'
      49 |                 BUILD_BUG_ON_MSG(__builtin_constant_p(_val) ?           \
         |                 ^~~~~~~~~~~~~~~~
   include/linux/bitfield.h:94:17: note: in expansion of macro '__BF_FIELD_CHECK'
      94 |                 __BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_PREP: ");    \
         |                 ^~~~~~~~~~~~~~~~
   drivers/dma/tegra186-gpc-dma.c:896:25: note: in expansion of macro 'FIELD_PREP'
     896 |                         FIELD_PREP(TEGRA_GPCDMA_HIGH_ADDR_DST_PTR, (dest >> 32));
         |                         ^~~~~~~~~~
>> drivers/dma/tegra186-gpc-dma.c:896:74: warning: right shift count >= width of type [-Wshift-count-overflow]
     896 |                         FIELD_PREP(TEGRA_GPCDMA_HIGH_ADDR_DST_PTR, (dest >> 32));
         |                                                                          ^~
   include/linux/compiler_types.h:315:23: note: in definition of macro '__compiletime_assert'
     315 |                 if (!(condition))                                       \
         |                       ^~~~~~~~~
   include/linux/compiler_types.h:335:9: note: in expansion of macro '_compiletime_assert'
     335 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
         |         ^~~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
      39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
         |                                     ^~~~~~~~~~~~~~~~~~
   include/linux/bitfield.h:49:17: note: in expansion of macro 'BUILD_BUG_ON_MSG'
      49 |                 BUILD_BUG_ON_MSG(__builtin_constant_p(_val) ?           \
         |                 ^~~~~~~~~~~~~~~~
   include/linux/bitfield.h:94:17: note: in expansion of macro '__BF_FIELD_CHECK'
      94 |                 __BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_PREP: ");    \
         |                 ^~~~~~~~~~~~~~~~
   drivers/dma/tegra186-gpc-dma.c:896:25: note: in expansion of macro 'FIELD_PREP'
     896 |                         FIELD_PREP(TEGRA_GPCDMA_HIGH_ADDR_DST_PTR, (dest >> 32));
         |                         ^~~~~~~~~~
   In file included from drivers/dma/tegra186-gpc-dma.c:8:
>> drivers/dma/tegra186-gpc-dma.c:896:74: warning: right shift count >= width of type [-Wshift-count-overflow]
     896 |                         FIELD_PREP(TEGRA_GPCDMA_HIGH_ADDR_DST_PTR, (dest >> 32));
         |                                                                          ^~
   include/linux/bitfield.h:95:34: note: in definition of macro 'FIELD_PREP'
      95 |                 ((typeof(_mask))(_val) << __bf_shf(_mask)) & (_mask);   \
         |                                  ^~~~
   In file included from <command-line>:
   drivers/dma/tegra186-gpc-dma.c: In function 'tegra_dma_prep_dma_memcpy':
   drivers/dma/tegra186-gpc-dma.c:964:65: warning: right shift count >= width of type [-Wshift-count-overflow]
     964 |                 FIELD_PREP(TEGRA_GPCDMA_HIGH_ADDR_SRC_PTR, (src >> 32));
         |                                                                 ^~
   include/linux/compiler_types.h:315:23: note: in definition of macro '__compiletime_assert'
     315 |                 if (!(condition))                                       \
         |                       ^~~~~~~~~
   include/linux/compiler_types.h:335:9: note: in expansion of macro '_compiletime_assert'
     335 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
         |         ^~~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
      39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
         |                                     ^~~~~~~~~~~~~~~~~~
   include/linux/bitfield.h:49:17: note: in expansion of macro 'BUILD_BUG_ON_MSG'
      49 |                 BUILD_BUG_ON_MSG(__builtin_constant_p(_val) ?           \
         |                 ^~~~~~~~~~~~~~~~
   include/linux/bitfield.h:94:17: note: in expansion of macro '__BF_FIELD_CHECK'
      94 |                 __BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_PREP: ");    \
         |                 ^~~~~~~~~~~~~~~~
   drivers/dma/tegra186-gpc-dma.c:964:17: note: in expansion of macro 'FIELD_PREP'
     964 |                 FIELD_PREP(TEGRA_GPCDMA_HIGH_ADDR_SRC_PTR, (src >> 32));
         |                 ^~~~~~~~~~
   drivers/dma/tegra186-gpc-dma.c:964:65: warning: right shift count >= width of type [-Wshift-count-overflow]
     964 |                 FIELD_PREP(TEGRA_GPCDMA_HIGH_ADDR_SRC_PTR, (src >> 32));
         |                                                                 ^~
   include/linux/compiler_types.h:315:23: note: in definition of macro '__compiletime_assert'
     315 |                 if (!(condition))                                       \
         |                       ^~~~~~~~~
   include/linux/compiler_types.h:335:9: note: in expansion of macro '_compiletime_assert'
     335 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
         |         ^~~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
      39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
         |                                     ^~~~~~~~~~~~~~~~~~
   include/linux/bitfield.h:49:17: note: in expansion of macro 'BUILD_BUG_ON_MSG'
      49 |                 BUILD_BUG_ON_MSG(__builtin_constant_p(_val) ?           \
         |                 ^~~~~~~~~~~~~~~~
   include/linux/bitfield.h:94:17: note: in expansion of macro '__BF_FIELD_CHECK'
      94 |                 __BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_PREP: ");    \
         |                 ^~~~~~~~~~~~~~~~
   drivers/dma/tegra186-gpc-dma.c:964:17: note: in expansion of macro 'FIELD_PREP'
     964 |                 FIELD_PREP(TEGRA_GPCDMA_HIGH_ADDR_SRC_PTR, (src >> 32));
         |                 ^~~~~~~~~~
   In file included from drivers/dma/tegra186-gpc-dma.c:8:
   drivers/dma/tegra186-gpc-dma.c:964:65: warning: right shift count >= width of type [-Wshift-count-overflow]
     964 |                 FIELD_PREP(TEGRA_GPCDMA_HIGH_ADDR_SRC_PTR, (src >> 32));
         |                                                                 ^~
   include/linux/bitfield.h:95:34: note: in definition of macro 'FIELD_PREP'
      95 |                 ((typeof(_mask))(_val) << __bf_shf(_mask)) & (_mask);   \
         |                                  ^~~~
   In file included from <command-line>:
   drivers/dma/tegra186-gpc-dma.c:966:66: warning: right shift count >= width of type [-Wshift-count-overflow]
     966 |                 FIELD_PREP(TEGRA_GPCDMA_HIGH_ADDR_DST_PTR, (dest >> 32));
         |                                                                  ^~
   include/linux/compiler_types.h:315:23: note: in definition of macro '__compiletime_assert'
     315 |                 if (!(condition))                                       \
         |                       ^~~~~~~~~
   include/linux/compiler_types.h:335:9: note: in expansion of macro '_compiletime_assert'
     335 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
         |         ^~~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
      39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
         |                                     ^~~~~~~~~~~~~~~~~~
   include/linux/bitfield.h:49:17: note: in expansion of macro 'BUILD_BUG_ON_MSG'
      49 |                 BUILD_BUG_ON_MSG(__builtin_constant_p(_val) ?           \
         |                 ^~~~~~~~~~~~~~~~
   include/linux/bitfield.h:94:17: note: in expansion of macro '__BF_FIELD_CHECK'
      94 |                 __BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_PREP: ");    \
         |                 ^~~~~~~~~~~~~~~~
   drivers/dma/tegra186-gpc-dma.c:966:17: note: in expansion of macro 'FIELD_PREP'
     966 |                 FIELD_PREP(TEGRA_GPCDMA_HIGH_ADDR_DST_PTR, (dest >> 32));
         |                 ^~~~~~~~~~
   drivers/dma/tegra186-gpc-dma.c:966:66: warning: right shift count >= width of type [-Wshift-count-overflow]
     966 |                 FIELD_PREP(TEGRA_GPCDMA_HIGH_ADDR_DST_PTR, (dest >> 32));
         |                                                                  ^~
   include/linux/compiler_types.h:315:23: note: in definition of macro '__compiletime_assert'
     315 |                 if (!(condition))                                       \
         |                       ^~~~~~~~~
   include/linux/compiler_types.h:335:9: note: in expansion of macro '_compiletime_assert'
     335 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
         |         ^~~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
      39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
         |                                     ^~~~~~~~~~~~~~~~~~
   include/linux/bitfield.h:49:17: note: in expansion of macro 'BUILD_BUG_ON_MSG'
      49 |                 BUILD_BUG_ON_MSG(__builtin_constant_p(_val) ?           \
         |                 ^~~~~~~~~~~~~~~~
   include/linux/bitfield.h:94:17: note: in expansion of macro '__BF_FIELD_CHECK'
      94 |                 __BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_PREP: ");    \
         |                 ^~~~~~~~~~~~~~~~
   drivers/dma/tegra186-gpc-dma.c:966:17: note: in expansion of macro 'FIELD_PREP'
     966 |                 FIELD_PREP(TEGRA_GPCDMA_HIGH_ADDR_DST_PTR, (dest >> 32));
         |                 ^~~~~~~~~~
   In file included from drivers/dma/tegra186-gpc-dma.c:8:


vim +896 drivers/dma/tegra186-gpc-dma.c

   841	
   842	static struct dma_async_tx_descriptor *
   843	tegra_dma_prep_dma_memset(struct dma_chan *dc, dma_addr_t dest, int value,
   844				  size_t len, unsigned long flags)
   845	{
   846		struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
   847		unsigned int max_dma_count = tdc->tdma->chip_data->max_dma_count;
   848		struct tegra_dma_sg_req *sg_req;
   849		struct tegra_dma_desc *dma_desc;
   850		unsigned long csr, mc_seq;
   851	
   852		if ((len & 3) || (dest & 3) || len > max_dma_count) {
   853			dev_err(tdc2dev(tdc),
   854				"DMA length/memory address is not supported\n");
   855			return NULL;
   856		}
   857	
   858		/* Set dma mode to fixed pattern */
   859		csr = TEGRA_GPCDMA_CSR_DMA_FIXED_PAT;
   860		/* Enable once or continuous mode */
   861		csr |= TEGRA_GPCDMA_CSR_ONCE;
   862		/* Enable IRQ mask */
   863		csr |= TEGRA_GPCDMA_CSR_IRQ_MASK;
   864		/* Enable the dma interrupt */
   865		if (flags & DMA_PREP_INTERRUPT)
   866			csr |= TEGRA_GPCDMA_CSR_IE_EOC;
   867		/* Configure default priority weight for the channel */
   868		csr |= FIELD_PREP(TEGRA_GPCDMA_CSR_WEIGHT, 1);
   869	
   870		mc_seq =  tdc_read(tdc, TEGRA_GPCDMA_CHAN_MCSEQ);
   871		/* retain stream-id and clean rest */
   872		mc_seq &= TEGRA_GPCDMA_MCSEQ_STREAM_ID0_MASK;
   873	
   874		/* Set the address wrapping */
   875		mc_seq |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_WRAP0,
   876							TEGRA_GPCDMA_MCSEQ_WRAP_NONE);
   877		mc_seq |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_WRAP1,
   878							TEGRA_GPCDMA_MCSEQ_WRAP_NONE);
   879	
   880		/* Program outstanding MC requests */
   881		mc_seq |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_REQ_COUNT, 1);
   882		/* Set burst size */
   883		mc_seq |= TEGRA_GPCDMA_MCSEQ_BURST_16;
   884	
   885		dma_desc = kzalloc(struct_size(dma_desc, sg_req, 1), GFP_NOWAIT);
   886		if (!dma_desc)
   887			return NULL;
   888	
   889		dma_desc->bytes_req = len;
   890		dma_desc->sg_count = 1;
   891		sg_req = dma_desc->sg_req;
   892	
   893		sg_req[0].ch_regs.src_ptr = 0;
   894		sg_req[0].ch_regs.dst_ptr = dest;
   895		sg_req[0].ch_regs.high_addr_ptr =
 > 896				FIELD_PREP(TEGRA_GPCDMA_HIGH_ADDR_DST_PTR, (dest >> 32));
   897		sg_req[0].ch_regs.fixed_pattern = value;
   898		/* Word count reg takes value as (N +1) words */
   899		sg_req[0].ch_regs.wcount = ((len - 4) >> 2);
   900		sg_req[0].ch_regs.csr = csr;
   901		sg_req[0].ch_regs.mmio_seq = 0;
   902		sg_req[0].ch_regs.mc_seq = mc_seq;
   903		sg_req[0].len = len;
   904	
   905		dma_desc->cyclic = false;
   906		return vchan_tx_prep(&tdc->vc, &dma_desc->vd, flags);
   907	}
   908	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

^ permalink raw reply	[flat|nested] 12+ messages in thread

* RE: [PATCH v18 2/4] dmaengine: tegra: Add tegra gpcdma driver
  2022-02-02 15:45   ` Dmitry Osipenko
@ 2022-02-03  3:44     ` Akhil R
  2022-02-03 18:22       ` Dmitry Osipenko
  0 siblings, 1 reply; 12+ messages in thread
From: Akhil R @ 2022-02-03  3:44 UTC (permalink / raw)
  To: Dmitry Osipenko, devicetree, dmaengine, Jonathan Hunter,
	Krishna Yarlagadda, Laxman Dewangan, linux-kernel, linux-tegra,
	p.zabel, Rajesh Gumasta, robh+dt, thierry.reding, vkoul
  Cc: Pavan Kunapuli

> ....
> > +static int tegra_dma_pause(struct tegra_dma_channel *tdc)
> > +{
> > +     int ret;
> > +     u32 val;
> > +
> > +     val = tdc_read(tdc, TEGRA_GPCDMA_CHAN_CSRE);
> > +     val |= TEGRA_GPCDMA_CHAN_CSRE_PAUSE;
> > +     tdc_write(tdc, TEGRA_GPCDMA_CHAN_CSRE, val);
> > +
> > +     /* Wait until busy bit is de-asserted */
> > +     ret = readl_relaxed_poll_timeout_atomic(tdc->tdma->base_addr +
> > +                     tdc->chan_base_offset + TEGRA_GPCDMA_CHAN_STATUS,
> > +                     val,
> > +                     !(val & TEGRA_GPCDMA_STATUS_BUSY),
> > +                     TEGRA_GPCDMA_BURST_COMPLETE_TIME,
> > +                     TEGRA_GPCDMA_BURST_COMPLETION_TIMEOUT);
> > +
> > +     return ret;
> > +}
> > +
> > +static int tegra_dma_device_pause(struct dma_chan *dc)
> > +{
> > +     struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
> > +     unsigned long flags;
> > +     int ret = 0;
> > +
> > +     if (!tdc->tdma->chip_data->hw_support_pause)
> > +             return -ENOSYS;
> > +
> > +     spin_lock_irqsave(&tdc->vc.lock, flags);
> > +     ret = tegra_dma_pause(tdc);
> > +     if (ret)
> > +             dev_err(tdc2dev(tdc), "DMA pause timed out\n");
> 
> Why error message shouldn't be printed by tegra_dma_terminate_all()?
> 
> The error message should be placed inside of tegra_dma_pause().
Okay. Agreed.
> 
> ...
> > +static int tegra_dma_stop_client(struct tegra_dma_channel *tdc)
> > +{
> > +     int ret;
> > +     unsigned long status;
> > +     u32 csr = tdc_read(tdc, TEGRA_GPCDMA_CHAN_CSR);
> > +
> > +     /*
> > +      * Change the client associated with the DMA channel
> > +      * to stop DMA engine from starting any more bursts for
> > +      * the given client and wait for in flight bursts to complete
> > +      */
> > +     csr &= ~(TEGRA_GPCDMA_CSR_REQ_SEL_MASK);
> > +     csr |= TEGRA_GPCDMA_CSR_REQ_SEL_UNUSED;
> > +     tdc_write(tdc, TEGRA_GPCDMA_CHAN_CSR, csr);
> > +
> > +     /* Wait for in flight data transfer to finish */
> > +     udelay(TEGRA_GPCDMA_BURST_COMPLETE_TIME);
> > +
> > +     /* If TX/RX path is still active wait till it becomes
> > +      * inactive
> > +      */
> > +
> > +     ret = readl_relaxed_poll_timeout_atomic(tdc->tdma->base_addr +
> > +                             tdc->chan_base_offset +
> > +                             TEGRA_GPCDMA_CHAN_STATUS,
> > +                             status,
> > +                             !(status & (TEGRA_GPCDMA_STATUS_CHANNEL_TX |
> > +                             TEGRA_GPCDMA_STATUS_CHANNEL_RX)),
> > +                             5,
> > +                             TEGRA_GPCDMA_BURST_COMPLETION_TIMEOUT);
> > +     if (ret) {
> > +             dev_err(tdc2dev(tdc), "Timeout waiting for DMA burst
> completion!\n");
> > +             tegra_dma_dump_chan_regs(tdc);
> > +     }
> > +
> > +     return ret;
> > +}
> > +
> > +static int tegra_dma_terminate_all(struct dma_chan *dc)
> > +{
> > +     struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
> > +     unsigned long flags;
> > +     LIST_HEAD(head);
> > +     int err;
> > +
> > +     spin_lock_irqsave(&tdc->vc.lock, flags);
> > +
> > +     if (tdc->dma_desc) {
> > +             err = tdc->tdma->chip_data->hw_support_pause ?
> > +                   tegra_dma_pause(tdc) :
> > +                   tegra_dma_stop_client(tdc);
> 
> The canonical coding style is:
> 
> if (tdc->tdma->chip_data->hw_support_pause)
>         err = tegra_dma_pause(tdc);
> else
>         err = tegra_dma_stop_client(tdc);
> 
Okay.
> 
> But why do you need to pause at all here and can't use
> tegra_dma_stop_client() even if pause is supported?

The recommended method to terminate a transfer in
between is to pause the channel first and then disable it.
This is more graceful and stable for the hardware.
stop_client() is more abrupt, though it does the job.

Thanks,
Akhil

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH v18 2/4] dmaengine: tegra: Add tegra gpcdma driver
  2022-02-03  3:44     ` Akhil R
@ 2022-02-03 18:22       ` Dmitry Osipenko
  2022-02-04  6:47         ` Akhil R
  0 siblings, 1 reply; 12+ messages in thread
From: Dmitry Osipenko @ 2022-02-03 18:22 UTC (permalink / raw)
  To: Akhil R, devicetree, dmaengine, Jonathan Hunter,
	Krishna Yarlagadda, Laxman Dewangan, linux-kernel, linux-tegra,
	p.zabel, Rajesh Gumasta, robh+dt, thierry.reding, vkoul
  Cc: Pavan Kunapuli

03.02.2022 06:44, Akhil R пишет:
>> But why do you need to pause at all here and can't use
>> tegra_dma_stop_client() even if pause is supported?
> The recommended method to terminate a transfer in
> between is to pause the channel first and then disable it.
> This is more graceful and stable for the hardware.
> stop_client() is more abrupt, though it does the job.

If there is no real practical difference, then I'd use the common method
only. This will make code cleaner and simpler a tad.

^ permalink raw reply	[flat|nested] 12+ messages in thread

* RE: [PATCH v18 2/4] dmaengine: tegra: Add tegra gpcdma driver
  2022-02-03 18:22       ` Dmitry Osipenko
@ 2022-02-04  6:47         ` Akhil R
  2022-02-04 12:15           ` Dmitry Osipenko
  0 siblings, 1 reply; 12+ messages in thread
From: Akhil R @ 2022-02-04  6:47 UTC (permalink / raw)
  To: Dmitry Osipenko, devicetree, dmaengine, Jonathan Hunter,
	Krishna Yarlagadda, Laxman Dewangan, linux-kernel, linux-tegra,
	p.zabel, Rajesh Gumasta, robh+dt, thierry.reding, vkoul
  Cc: Pavan Kunapuli

> 03.02.2022 06:44, Akhil R пишет:
> >> But why do you need to pause at all here and can't use
> >> tegra_dma_stop_client() even if pause is supported?
> > The recommended method to terminate a transfer in
> > between is to pause the channel first and then disable it.
> > This is more graceful and stable for the hardware.
> > stop_client() is more abrupt, though it does the job.
> 
> If there is no real practical difference, then I'd use the common method
> only. This will make code cleaner and simpler a tad.
This is the documented way of clean exit from a transfer, especially for
cyclic transfers where the DMA is configured in continuous mode.
I guess it might not be a good idea to deviate from that unless there is
something demanding it compulsorily.

I agree that the code will be cleaner. I would try to see if I can find a cleaner
way to do this. Please do let me know if you have any suggestion.

Thanks,
Akhil


^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH v18 2/4] dmaengine: tegra: Add tegra gpcdma driver
  2022-02-04  6:47         ` Akhil R
@ 2022-02-04 12:15           ` Dmitry Osipenko
  2022-02-04 12:28             ` Dmitry Osipenko
  0 siblings, 1 reply; 12+ messages in thread
From: Dmitry Osipenko @ 2022-02-04 12:15 UTC (permalink / raw)
  To: Akhil R, devicetree, dmaengine, Jonathan Hunter,
	Krishna Yarlagadda, Laxman Dewangan, linux-kernel, linux-tegra,
	p.zabel, Rajesh Gumasta, robh+dt, thierry.reding, vkoul
  Cc: Pavan Kunapuli

04.02.2022 09:47, Akhil R пишет:
>> 03.02.2022 06:44, Akhil R пишет:
>>>> But why do you need to pause at all here and can't use
>>>> tegra_dma_stop_client() even if pause is supported?
>>> The recommended method to terminate a transfer in
>>> between is to pause the channel first and then disable it.
>>> This is more graceful and stable for the hardware.
>>> stop_client() is more abrupt, though it does the job.
>>
>> If there is no real practical difference, then I'd use the common method
>> only. This will make code cleaner and simpler a tad.
> This is the documented way of clean exit from a transfer, especially for
> cyclic transfers where the DMA is configured in continuous mode.
> I guess it might not be a good idea to deviate from that unless there is
> something demanding it compulsorily.
> 
> I agree that the code will be cleaner. I would try to see if I can find a cleaner
> way to do this. Please do let me know if you have any suggestion.

Will be great if you could find out and provide a detailed explanation
about the exact differences of the methods from software perspective.
Try to ask the hardware people.

If you won't be able to find out, then use both methods. Then you could
specify the "pause" callback within the tegra_dma_chip_data
[tdma->chip_data->pause(tdma)], instead of using condition in the code.

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH v18 2/4] dmaengine: tegra: Add tegra gpcdma driver
  2022-02-04 12:15           ` Dmitry Osipenko
@ 2022-02-04 12:28             ` Dmitry Osipenko
  0 siblings, 0 replies; 12+ messages in thread
From: Dmitry Osipenko @ 2022-02-04 12:28 UTC (permalink / raw)
  To: Akhil R, devicetree, dmaengine, Jonathan Hunter,
	Krishna Yarlagadda, Laxman Dewangan, linux-kernel, linux-tegra,
	p.zabel, Rajesh Gumasta, robh+dt, thierry.reding, vkoul
  Cc: Pavan Kunapuli

04.02.2022 15:15, Dmitry Osipenko пишет:
> 04.02.2022 09:47, Akhil R пишет:
>>> 03.02.2022 06:44, Akhil R пишет:
>>>>> But why do you need to pause at all here and can't use
>>>>> tegra_dma_stop_client() even if pause is supported?
>>>> The recommended method to terminate a transfer in
>>>> between is to pause the channel first and then disable it.
>>>> This is more graceful and stable for the hardware.
>>>> stop_client() is more abrupt, though it does the job.
>>>
>>> If there is no real practical difference, then I'd use the common method
>>> only. This will make code cleaner and simpler a tad.
>> This is the documented way of clean exit from a transfer, especially for
>> cyclic transfers where the DMA is configured in continuous mode.
>> I guess it might not be a good idea to deviate from that unless there is
>> something demanding it compulsorily.
>>
>> I agree that the code will be cleaner. I would try to see if I can find a cleaner
>> way to do this. Please do let me know if you have any suggestion.
> 
> Will be great if you could find out and provide a detailed explanation
> about the exact differences of the methods from software perspective.
> Try to ask the hardware people.
> 
> If you won't be able to find out, then use both methods. Then you could
> specify the "pause" callback within the tegra_dma_chip_data
> [tdma->chip_data->pause(tdma)], instead of using condition in the code.

s/pause/terminate/

^ permalink raw reply	[flat|nested] 12+ messages in thread

end of thread, other threads:[~2022-02-04 12:28 UTC | newest]

Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-02-01 15:26 [PATCH v18 0/4] Add NVIDIA Tegra GPC-DMA driver Akhil R
2022-02-01 15:26 ` [PATCH v18 1/4] dt-bindings: dmaengine: Add doc for tegra gpcdma Akhil R
2022-02-01 15:26 ` [PATCH v18 2/4] dmaengine: tegra: Add tegra gpcdma driver Akhil R
2022-02-02 15:45   ` Dmitry Osipenko
2022-02-03  3:44     ` Akhil R
2022-02-03 18:22       ` Dmitry Osipenko
2022-02-04  6:47         ` Akhil R
2022-02-04 12:15           ` Dmitry Osipenko
2022-02-04 12:28             ` Dmitry Osipenko
2022-02-03  0:18   ` kernel test robot
2022-02-01 15:26 ` [PATCH v18 3/4] arm64: defconfig: tegra: Enable GPCDMA Akhil R
2022-02-01 15:26 ` [PATCH v18 4/4] arm64: tegra: Add GPCDMA node for tegra186 and tegra194 Akhil R

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