[PATCH v5 0/4] add mailbox support for i.MX7D

[PATCH v5 0/4] add mailbox support for i.MX7D

[Oleksij Rempel]

20180621 changes v5:
- DT: revert most of the changes from previous version
- imx-mailbox: remove struct imx_mu_cfg
- imx-mailbox: remove !! from imx_mu_last_tx_done()

20180618 changes v4:
- DT: change fsl,mu-side-a to fsl,mu-side-b
- DT: split the patches.
- DT: add all currently known SoCs.
- imx-mailbox: free allocated irq name on channel shutdown
- imx-mailbox: rename *_imx7 functions to *_generic

20180615 changes v3:
- DT: remove prosaic part of documentation. It describes software
  or firmware specific usage and not relevant for HW description.
- DT: use <soc>-mu instead of <soc>-mu-<mu side> and add fsl,mu-side-a
  parameter.
- DT: add most of know i.MX variants with MU
- imx-mailbox: use macros instead of precalculated bit index.
- imx-mailbox: remove warning message for clk.
- imx-mailbox: use imx_mu_chan[%idx] for devm_request_irq.
- imx-mailbox: depend on ARCH_MXC instead of SOX_IMX7

20180615 changes v2:
- DT: use mailbox@ instead of mu@
- DT: change interrupts description
- clk: use imx_clk_gate4 instead of imx_clk_gate2
- imx-mailbox: remove last_tx_done support
- imx-mailbox: fix module description 

This patches are providing support for mailbox (Messaging Unit)
for i.MX7D.
Functionality was tested on PHYTEC phyBOARD-Zeta i.MX7D with
Linux running on all cores: ARM Cortex-A7 and ARM Cortex-M4.

Both parts of i.MX messaging Unit are visible for all CPUs available
on i.MX7D. Communication worked independent of MU side in combination
with CPU. For example MU-A used on ARM Cortex-A7 and MU-B used on ARM Cortex-M4
or other ways around.

Dong Aisheng (1):
  dt-bindings: arm: fsl: add mu binding doc

Oleksij Rempel (3):
  dt-bindings: mailbox: imx-mu: add generic MU channel support
  ARM: dts: imx7s: add i.MX7 messaging unit support
  mailbox: Add support for i.MX7D messaging unit

 .../devicetree/bindings/mailbox/fsl,mu.txt    |  41 +++
 arch/arm/boot/dts/imx7s.dtsi                  |  19 ++
 drivers/mailbox/Kconfig                       |   6 +
 drivers/mailbox/Makefile                      |   2 +
 drivers/mailbox/imx-mailbox.c                 | 274 ++++++++++++++++++
 5 files changed, 342 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mailbox/fsl,mu.txt
 create mode 100644 drivers/mailbox/imx-mailbox.c

-- 
2.18.0

[PATCH v5 1/4] dt-bindings: arm: fsl: add mu binding doc

[Oleksij Rempel]

From: Dong Aisheng <aisheng.dong@nxp.com>

The Messaging Unit module enables two processors within
the SoC to communicate and coordinate by passing messages
(e.g. data, status and control) through the MU interface.

Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: devicetree@vger.kernel.org
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
---
 .../devicetree/bindings/mailbox/fsl,mu.txt    | 34 +++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mailbox/fsl,mu.txt

diff --git a/Documentation/devicetree/bindings/mailbox/fsl,mu.txt b/Documentation/devicetree/bindings/mailbox/fsl,mu.txt
new file mode 100644
index 000000000000..90e4905dfc69
--- /dev/null
+++ b/Documentation/devicetree/bindings/mailbox/fsl,mu.txt
@@ -0,0 +1,34 @@
+NXP i.MX Messaging Unit (MU)
+--------------------------------------------------------------------
+
+The Messaging Unit module enables two processors within the SoC to
+communicate and coordinate by passing messages (e.g. data, status
+and control) through the MU interface. The MU also provides the ability
+for one processor to signal the other processor using interrupts.
+
+Because the MU manages the messaging between processors, the MU uses
+different clocks (from each side of the different peripheral buses).
+Therefore, the MU must synchronize the accesses from one side to the
+other. The MU accomplishes synchronization using two sets of matching
+registers (Processor A-facing, Processor B-facing).
+
+Messaging Unit Device Node:
+=============================
+
+Required properties:
+-------------------
+- compatible :	should be "fsl,<chip>-mu", the supported chips include
+		imx8qxp, imx8qm.
+- reg :		Should contain the registers location and length
+- interrupts :	Interrupt number. The interrupt specifier format depends
+		on the interrupt controller parent.
+- #mbox-cells:  Must be 0. Number of cells in a mailbox
+
+Examples:
+--------
+lsio_mu0: mailbox@5d1b0000 {
+	compatible = "fsl,imx8qxp-mu";
+	reg = <0x0 0x5d1b0000 0x0 0x10000>;
+	interrupts = <GIC_SPI 176 IRQ_TYPE_LEVEL_HIGH>;
+	#mbox-cells = <0>;
+};
-- 
2.18.0

RE: [PATCH v5 1/4] dt-bindings: arm: fsl: add mu binding doc

[A.s. Dong]

Hi Oleksij,

> -----Original Message-----
> From: Oleksij Rempel [mailto:o.rempel@pengutronix.de]
> Sent: Saturday, July 21, 2018 9:08 PM
> To: Shawn Guo <shawnguo@kernel.org>; Fabio Estevam
> <fabio.estevam@nxp.com>; Rob Herring <robh+dt@kernel.org>; Mark
> Rutland <mark.rutland@arm.com>; A.s. Dong <aisheng.dong@nxp.com>;
> Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
> Cc: Sascha Hauer <kernel@pengutronix.de>; devicetree@vger.kernel.org;
> linux-arm-kernel@lists.infradead.org; dl-linux-imx <linux-imx@nxp.com>
> Subject: [PATCH v5 1/4] dt-bindings: arm: fsl: add mu binding doc
> 
> From: Dong Aisheng <aisheng.dong@nxp.com>
> 
> The Messaging Unit module enables two processors within the SoC to
> communicate and coordinate by passing messages (e.g. data, status and
> control) through the MU interface.
> 
> Cc: Shawn Guo <shawnguo@kernel.org>
> Cc: Sascha Hauer <kernel@pengutronix.de>
> Cc: Fabio Estevam <fabio.estevam@nxp.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: devicetree@vger.kernel.org
> Reviewed-by: Rob Herring <robh@kernel.org>
> Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>

Just let you know this patch also depends on another one which is already
Acked by Rob.
If you resend, would you please help pick that one in this series as well?

 [V4,1/5] dt-bindings: mailbox: allow mbox-cells to be equal to 0
https://patchwork.kernel.org/patch/10513197/

Regards
Dong Aisheng

> ---
>  .../devicetree/bindings/mailbox/fsl,mu.txt    | 34 +++++++++++++++++++
>  1 file changed, 34 insertions(+)
>  create mode 100644
> Documentation/devicetree/bindings/mailbox/fsl,mu.txt
> 
> diff --git a/Documentation/devicetree/bindings/mailbox/fsl,mu.txt
> b/Documentation/devicetree/bindings/mailbox/fsl,mu.txt
> new file mode 100644
> index 000000000000..90e4905dfc69
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mailbox/fsl,mu.txt
> @@ -0,0 +1,34 @@
> +NXP i.MX Messaging Unit (MU)
> +--------------------------------------------------------------------
> +
> +The Messaging Unit module enables two processors within the SoC to
> +communicate and coordinate by passing messages (e.g. data, status and
> +control) through the MU interface. The MU also provides the ability for
> +one processor to signal the other processor using interrupts.
> +
> +Because the MU manages the messaging between processors, the MU
> uses
> +different clocks (from each side of the different peripheral buses).
> +Therefore, the MU must synchronize the accesses from one side to the
> +other. The MU accomplishes synchronization using two sets of matching
> +registers (Processor A-facing, Processor B-facing).
> +
> +Messaging Unit Device Node:
> +=============================
> +
> +Required properties:
> +-------------------
> +- compatible :	should be "fsl,<chip>-mu", the supported chips include
> +		imx8qxp, imx8qm.
> +- reg :		Should contain the registers location and length
> +- interrupts :	Interrupt number. The interrupt specifier format depends
> +		on the interrupt controller parent.
> +- #mbox-cells:  Must be 0. Number of cells in a mailbox
> +
> +Examples:
> +--------
> +lsio_mu0: mailbox@5d1b0000 {
> +	compatible = "fsl,imx8qxp-mu";
> +	reg = <0x0 0x5d1b0000 0x0 0x10000>;
> +	interrupts = <GIC_SPI 176 IRQ_TYPE_LEVEL_HIGH>;
> +	#mbox-cells = <0>;
> +};
> --
> 2.18.0

[PATCH v5 2/4] dt-bindings: mailbox: imx-mu: add generic MU channel support

[Oleksij Rempel]

Each MU has four pairs of rx/tx data register with four rx/tx interrupts
which can also be used as a separate channel.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
 Documentation/devicetree/bindings/mailbox/fsl,mu.txt | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/mailbox/fsl,mu.txt b/Documentation/devicetree/bindings/mailbox/fsl,mu.txt
index 90e4905dfc69..113d6ab931ef 100644
--- a/Documentation/devicetree/bindings/mailbox/fsl,mu.txt
+++ b/Documentation/devicetree/bindings/mailbox/fsl,mu.txt
@@ -22,7 +22,14 @@ Required properties:
 - reg :		Should contain the registers location and length
 - interrupts :	Interrupt number. The interrupt specifier format depends
 		on the interrupt controller parent.
-- #mbox-cells:  Must be 0. Number of cells in a mailbox
+- #mbox-cells:  Must be:
+		0 - for single channel mode. i.MX8* SCU protocol specific.
+		1 - for multichannel (generic) mode.
+
+Optional properties:
+-------------------
+- clocks :	phandle to the input clock.
+- fsl,mu-side-b : Should be set for side B MU.
 
 Examples:
 --------
-- 
2.18.0

RE: [PATCH v5 2/4] dt-bindings: mailbox: imx-mu: add generic MU channel support

[A.s. Dong]

> -----Original Message-----
> From: Oleksij Rempel [mailto:o.rempel@pengutronix.de]
> Sent: Saturday, July 21, 2018 9:08 PM
> To: Shawn Guo <shawnguo@kernel.org>; Fabio Estevam
> <fabio.estevam@nxp.com>; Rob Herring <robh+dt@kernel.org>; Mark
> Rutland <mark.rutland@arm.com>; A.s. Dong <aisheng.dong@nxp.com>;
> Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
> Cc: Oleksij Rempel <o.rempel@pengutronix.de>; kernel@pengutronix.de;
> linux-arm-kernel@lists.infradead.org; devicetree@vger.kernel.org; dl-linux-
> imx <linux-imx@nxp.com>
> Subject: [PATCH v5 2/4] dt-bindings: mailbox: imx-mu: add generic MU
> channel support
> 
> Each MU has four pairs of rx/tx data register with four rx/tx interrupts which
> can also be used as a separate channel.
> 
> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>

Reviewed-by: Dong Aisheng <aisheng.dong@nxp.com>

Regards
Dong Aisheng

> ---
>  Documentation/devicetree/bindings/mailbox/fsl,mu.txt | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/mailbox/fsl,mu.txt
> b/Documentation/devicetree/bindings/mailbox/fsl,mu.txt
> index 90e4905dfc69..113d6ab931ef 100644
> --- a/Documentation/devicetree/bindings/mailbox/fsl,mu.txt
> +++ b/Documentation/devicetree/bindings/mailbox/fsl,mu.txt
> @@ -22,7 +22,14 @@ Required properties:
>  - reg :		Should contain the registers location and length
>  - interrupts :	Interrupt number. The interrupt specifier format depends
>  		on the interrupt controller parent.
> -- #mbox-cells:  Must be 0. Number of cells in a mailbox
> +- #mbox-cells:  Must be:
> +		0 - for single channel mode. i.MX8* SCU protocol specific.
> +		1 - for multichannel (generic) mode.
> +
> +Optional properties:
> +-------------------
> +- clocks :	phandle to the input clock.
> +- fsl,mu-side-b : Should be set for side B MU.
> 
>  Examples:
>  --------
> --
> 2.18.0

[PATCH v5 3/4] ARM: dts: imx7s: add i.MX7 messaging unit support

[Oleksij Rempel]

Define the Messaging Unit (MU) for i.MX7 in the processor's dtsi.
The respective driver is added in the next commit.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
 arch/arm/boot/dts/imx7s.dtsi | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/arch/arm/boot/dts/imx7s.dtsi b/arch/arm/boot/dts/imx7s.dtsi
index ce85b3ca1a55..038e0eafc549 100644
--- a/arch/arm/boot/dts/imx7s.dtsi
+++ b/arch/arm/boot/dts/imx7s.dtsi
@@ -1001,6 +1001,25 @@
 				status = "disabled";
 			};
 
+			mu0a: mailbox@30aa0000 {
+				compatible = "fsl,imx7s-mu";
+				reg = <0x30aa0000 0x10000>;
+				interrupts = <GIC_SPI 88 IRQ_TYPE_LEVEL_HIGH>;
+				clocks = <&clks IMX7D_MU_ROOT_CLK>;
+				#mbox-cells = <1>;
+				status = "disabled";
+			};
+
+			mu0b: mailbox@30ab0000 {
+				compatible = "fsl,imx7s-mu";
+				reg = <0x30ab0000 0x10000>;
+				interrupts = <GIC_SPI 97 IRQ_TYPE_LEVEL_HIGH>;
+				clocks = <&clks IMX7D_MU_ROOT_CLK>;
+				#mbox-cells = <1>;
+				fsl,mu-side-b;
+				status = "disabled";
+			};
+
 			usbotg1: usb@30b10000 {
 				compatible = "fsl,imx7d-usb", "fsl,imx27-usb";
 				reg = <0x30b10000 0x200>;
-- 
2.18.0

RE: [PATCH v5 3/4] ARM: dts: imx7s: add i.MX7 messaging unit support

[A.s. Dong]

> -----Original Message-----
> From: Oleksij Rempel [mailto:o.rempel@pengutronix.de]
> Sent: Saturday, July 21, 2018 9:08 PM
> To: Shawn Guo <shawnguo@kernel.org>; Fabio Estevam
> <fabio.estevam@nxp.com>; Rob Herring <robh+dt@kernel.org>; Mark
> Rutland <mark.rutland@arm.com>; A.s. Dong <aisheng.dong@nxp.com>;
> Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
> Cc: Oleksij Rempel <o.rempel@pengutronix.de>; kernel@pengutronix.de;
> linux-arm-kernel@lists.infradead.org; devicetree@vger.kernel.org; dl-linux-
> imx <linux-imx@nxp.com>
> Subject: [PATCH v5 3/4] ARM: dts: imx7s: add i.MX7 messaging unit support
> 
> Define the Messaging Unit (MU) for i.MX7 in the processor's dtsi.
> The respective driver is added in the next commit.
> 
> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
> ---
>  arch/arm/boot/dts/imx7s.dtsi | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
> 
> diff --git a/arch/arm/boot/dts/imx7s.dtsi b/arch/arm/boot/dts/imx7s.dtsi
> index ce85b3ca1a55..038e0eafc549 100644
> --- a/arch/arm/boot/dts/imx7s.dtsi
> +++ b/arch/arm/boot/dts/imx7s.dtsi
> @@ -1001,6 +1001,25 @@
>  				status = "disabled";
>  			};
> 
> +			mu0a: mailbox@30aa0000 {
> +				compatible = "fsl,imx7s-mu";

You probably needs a fallback compatible as well as they're the same one.
e.g..
compatible = "fsl,imx7s-mu", "fsl,imx6sx-mu";

Otherwise, you can added my tag.

Reviewed-by: Dong Aisheng <aisheng.dong@nxp.com>

Regards
Dong Aisheng

> +				reg = <0x30aa0000 0x10000>;
> +				interrupts = <GIC_SPI 88
> IRQ_TYPE_LEVEL_HIGH>;
> +				clocks = <&clks IMX7D_MU_ROOT_CLK>;
> +				#mbox-cells = <1>;
> +				status = "disabled";
> +			};
> +
> +			mu0b: mailbox@30ab0000 {
> +				compatible = "fsl,imx7s-mu";
> +				reg = <0x30ab0000 0x10000>;
> +				interrupts = <GIC_SPI 97
> IRQ_TYPE_LEVEL_HIGH>;
> +				clocks = <&clks IMX7D_MU_ROOT_CLK>;
> +				#mbox-cells = <1>;
> +				fsl,mu-side-b;
> +				status = "disabled";
> +			};
> +
>  			usbotg1: usb@30b10000 {
>  				compatible = "fsl,imx7d-usb", "fsl,imx27-usb";
>  				reg = <0x30b10000 0x200>;
> --
> 2.18.0

[PATCH v5 4/4] mailbox: Add support for i.MX7D messaging unit

[Oleksij Rempel]

The Mailbox controller is able to send messages (up to 4 32 bit words)
between the endpoints.

This driver was tested using the mailbox-test driver sending messages
between the Cortex-A7 and the Cortex-M4.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
 drivers/mailbox/Kconfig       |   6 +
 drivers/mailbox/Makefile      |   2 +
 drivers/mailbox/imx-mailbox.c | 274 ++++++++++++++++++++++++++++++++++
 3 files changed, 282 insertions(+)
 create mode 100644 drivers/mailbox/imx-mailbox.c

diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index a2bb27446dce..79060ddc380d 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig
@@ -15,6 +15,12 @@ config ARM_MHU
 	  The controller has 3 mailbox channels, the last of which can be
 	  used in Secure mode only.
 
+config IMX_MBOX
+	tristate "i.MX Mailbox"
+	depends on ARCH_MXC || COMPILE_TEST
+	help
+	  Mailbox implementation for i.MX Messaging Unit (MU).
+
 config PLATFORM_MHU
 	tristate "Platform MHU Mailbox"
 	depends on OF
diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
index cc23c3a43fcd..ba2fe1b6dd62 100644
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile
@@ -7,6 +7,8 @@ obj-$(CONFIG_MAILBOX_TEST)	+= mailbox-test.o
 
 obj-$(CONFIG_ARM_MHU)	+= arm_mhu.o
 
+obj-$(CONFIG_IMX_MBOX)	+= imx-mailbox.o
+
 obj-$(CONFIG_PLATFORM_MHU)	+= platform_mhu.o
 
 obj-$(CONFIG_PL320_MBOX)	+= pl320-ipc.o
diff --git a/drivers/mailbox/imx-mailbox.c b/drivers/mailbox/imx-mailbox.c
new file mode 100644
index 000000000000..46f2453b144a
--- /dev/null
+++ b/drivers/mailbox/imx-mailbox.c
@@ -0,0 +1,274 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2018 Pengutronix, Oleksij Rempel <o.rempel@pengutronix.de>
+ */
+
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/mailbox_controller.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+
+/* Transmit Register */
+#define IMX_MU_xTRn(x)		(0x00 + 4 * (x))
+/* Receive Register */
+#define IMX_MU_xRRn(x)		(0x10 + 4 * (x))
+/* Status Register */
+#define IMX_MU_xSR		0x20
+#define IMX_MU_xSR_TEn(x)	BIT(20 + (3 - (x)))
+#define IMX_MU_xSR_RFn(x)	BIT(24 + (3 - (x)))
+#define IMX_MU_xSR_BRDIP	BIT(9)
+
+/* Control Register */
+#define IMX_MU_xCR		0x24
+/* Transmit Interrupt Enable */
+#define IMX_MU_xCR_TIEn(x)	BIT(20 + (3 - (x)))
+/* Receive Interrupt Enable */
+#define IMX_MU_xCR_RIEn(x)	BIT(24 + (3 - (x)))
+
+#define IMX_MU_CHANS	4u
+
+struct imx_mu_con_priv {
+	int			irq;
+	unsigned int		idx;
+	char			*irq_desc;
+};
+
+struct imx_mu_priv {
+	struct device		*dev;
+	void __iomem		*base;
+
+	struct mbox_controller	mbox;
+	struct mbox_chan	mbox_chans[IMX_MU_CHANS];
+
+	struct imx_mu_con_priv  con_priv[IMX_MU_CHANS];
+	struct clk		*clk;
+
+	bool			side_b;
+};
+
+static struct imx_mu_priv *to_imx_mu_priv(struct mbox_controller *mbox)
+{
+	return container_of(mbox, struct imx_mu_priv, mbox);
+}
+
+static void imx_mu_write(struct imx_mu_priv *priv, u32 val, u32 offs)
+{
+	iowrite32(val, priv->base + offs);
+}
+
+static u32 imx_mu_read(struct imx_mu_priv *priv, u32 offs)
+{
+	return ioread32(priv->base + offs);
+}
+
+static u32 imx_mu_rmw(struct imx_mu_priv *priv, u32 offs, u32 set, u32 clr)
+{
+	u32 val;
+
+	val = imx_mu_read(priv, offs);
+	val &= ~clr;
+	val |= set;
+	imx_mu_write(priv, val, offs);
+
+	return val;
+}
+
+static irqreturn_t imx_mu_isr(int irq, void *p)
+{
+	struct mbox_chan *chan = p;
+	struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
+	struct imx_mu_con_priv *cp = chan->con_priv;
+	u32 val, ctrl, dat;
+
+	ctrl = imx_mu_read(priv, IMX_MU_xCR);
+	val = imx_mu_read(priv, IMX_MU_xSR);
+	val &= IMX_MU_xSR_TEn(cp->idx) | IMX_MU_xSR_RFn(cp->idx);
+	val &= ctrl & (IMX_MU_xCR_TIEn(cp->idx) | IMX_MU_xCR_RIEn(cp->idx));
+	if (!val)
+		return IRQ_NONE;
+
+	if (val & IMX_MU_xSR_TEn(cp->idx)) {
+		imx_mu_rmw(priv, IMX_MU_xCR, 0, IMX_MU_xCR_TIEn(cp->idx));
+		mbox_chan_txdone(chan, 0);
+	}
+
+	if (val & IMX_MU_xSR_RFn(cp->idx)) {
+		dat = imx_mu_read(priv, IMX_MU_xRRn(cp->idx));
+		mbox_chan_received_data(chan, (void *)&dat);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static bool imx_mu_last_tx_done(struct mbox_chan *chan)
+{
+	struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
+	struct imx_mu_con_priv *cp = chan->con_priv;
+	u32 val;
+
+	val = imx_mu_read(priv, IMX_MU_xSR);
+	/* test if transmit register is empty */
+	return val & IMX_MU_xSR_TEn(cp->idx);
+}
+
+static int imx_mu_send_data(struct mbox_chan *chan, void *data)
+{
+	struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
+	struct imx_mu_con_priv *cp = chan->con_priv;
+	u32 *arg = data;
+
+	if (!imx_mu_last_tx_done(chan))
+		return -EBUSY;
+
+	imx_mu_write(priv, *arg, IMX_MU_xTRn(cp->idx));
+	imx_mu_rmw(priv, IMX_MU_xCR, IMX_MU_xSR_TEn(cp->idx), 0);
+
+	return 0;
+}
+
+static int imx_mu_startup(struct mbox_chan *chan)
+{
+	struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
+	struct imx_mu_con_priv *cp = chan->con_priv;
+	int ret;
+
+	cp->irq_desc = devm_kasprintf(priv->dev, GFP_KERNEL, "imx_mu_chan[%i]",
+				      cp->idx);
+	if (!cp->irq_desc)
+		return -ENOMEM;
+
+	ret = devm_request_irq(priv->dev, cp->irq, imx_mu_isr,
+			       IRQF_SHARED, cp->irq_desc, chan);
+	if (ret) {
+		dev_err(priv->dev,
+			"Unable to acquire IRQ %d\n", cp->irq);
+		return ret;
+	}
+
+	imx_mu_rmw(priv, IMX_MU_xCR, IMX_MU_xCR_RIEn(cp->idx), 0);
+
+	return 0;
+}
+
+static void imx_mu_shutdown(struct mbox_chan *chan)
+{
+	struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
+	struct imx_mu_con_priv *cp = chan->con_priv;
+
+	imx_mu_rmw(priv, IMX_MU_xCR, 0,
+		   IMX_MU_xCR_TIEn(cp->idx) | IMX_MU_xCR_RIEn(cp->idx));
+
+	devm_free_irq(priv->dev, cp->irq, chan);
+	devm_kfree(priv->dev, cp->irq_desc);
+}
+
+static const struct mbox_chan_ops imx_mu_ops = {
+	.send_data = imx_mu_send_data,
+	.startup = imx_mu_startup,
+	.shutdown = imx_mu_shutdown,
+};
+
+static void imx_mu_init_generic(struct imx_mu_priv *priv)
+{
+	if (priv->side_b)
+		return;
+
+	/* Set default MU configuration */
+	imx_mu_write(priv, 0, IMX_MU_xCR);
+}
+
+static int imx_mu_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct resource *iomem;
+	struct imx_mu_priv *priv;
+	unsigned int i;
+	int irq, ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->dev = dev;
+
+	iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	priv->base = devm_ioremap_resource(&pdev->dev, iomem);
+	if (IS_ERR(priv->base))
+		return PTR_ERR(priv->base);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	priv->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(priv->clk)) {
+		if (PTR_ERR(priv->clk) != -ENOENT)
+			return PTR_ERR(priv->clk);
+
+		priv->clk = NULL;
+	}
+
+	ret = clk_prepare_enable(priv->clk);
+	if (ret) {
+		dev_err(dev, "Failed to enable clock\n");
+		return ret;
+	}
+
+	for (i = 0; i < IMX_MU_CHANS; i++) {
+		struct imx_mu_con_priv *cp = &priv->con_priv[i];
+
+		cp->idx = i;
+		cp->irq = irq;
+		priv->mbox_chans[i].con_priv = cp;
+	}
+
+	if (of_property_read_bool(np, "fsl,mu-side-b"))
+		priv->side_b = true;
+
+	priv->mbox.dev = dev;
+	priv->mbox.ops = &imx_mu_ops;
+	priv->mbox.chans = priv->mbox_chans;
+	priv->mbox.num_chans = IMX_MU_CHANS;
+	priv->mbox.txdone_irq = true;
+
+	platform_set_drvdata(pdev, priv);
+
+	imx_mu_init_generic(priv);
+
+	return mbox_controller_register(&priv->mbox);
+}
+
+static int imx_mu_remove(struct platform_device *pdev)
+{
+	struct imx_mu_priv *priv = platform_get_drvdata(pdev);
+
+	mbox_controller_unregister(&priv->mbox);
+	clk_disable_unprepare(priv->clk);
+
+	return 0;
+}
+
+static const struct of_device_id imx_mu_dt_ids[] = {
+	{ .compatible = "fsl,imx6sx-mu" },
+	{ .compatible = "fsl,imx7s-mu" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, imx_mu_dt_ids);
+
+static struct platform_driver imx_mu_driver = {
+	.probe		= imx_mu_probe,
+	.remove		= imx_mu_remove,
+	.driver = {
+		.name	= "imx_mu",
+		.of_match_table = imx_mu_dt_ids,
+	},
+};
+module_platform_driver(imx_mu_driver);
+
+MODULE_AUTHOR("Oleksij Rempel <o.rempel@pengutronix.de>");
+MODULE_DESCRIPTION("Message Unit driver for i.MX");
+MODULE_LICENSE("GPL v2");
-- 
2.18.0

RE: [PATCH v5 4/4] mailbox: Add support for i.MX7D messaging unit

[A.s. Dong]

> -----Original Message-----
> From: Oleksij Rempel [mailto:o.rempel@pengutronix.de]
> Sent: Saturday, July 21, 2018 9:08 PM
> To: Shawn Guo <shawnguo@kernel.org>; Fabio Estevam
> <fabio.estevam@nxp.com>; Rob Herring <robh+dt@kernel.org>; Mark
> Rutland <mark.rutland@arm.com>; A.s. Dong <aisheng.dong@nxp.com>;
> Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
> Cc: Oleksij Rempel <o.rempel@pengutronix.de>; kernel@pengutronix.de;
> linux-arm-kernel@lists.infradead.org; devicetree@vger.kernel.org; dl-linux-
> imx <linux-imx@nxp.com>
> Subject: [PATCH v5 4/4] mailbox: Add support for i.MX7D messaging unit
> 
> The Mailbox controller is able to send messages (up to 4 32 bit words)
> between the endpoints.
> 
> This driver was tested using the mailbox-test driver sending messages
> between the Cortex-A7 and the Cortex-M4.
> 
> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
> ---
>  drivers/mailbox/Kconfig       |   6 +
>  drivers/mailbox/Makefile      |   2 +
>  drivers/mailbox/imx-mailbox.c | 274
> ++++++++++++++++++++++++++++++++++
>  3 files changed, 282 insertions(+)
>  create mode 100644 drivers/mailbox/imx-mailbox.c
> 
> diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig index
> a2bb27446dce..79060ddc380d 100644
> --- a/drivers/mailbox/Kconfig
> +++ b/drivers/mailbox/Kconfig
> @@ -15,6 +15,12 @@ config ARM_MHU
>  	  The controller has 3 mailbox channels, the last of which can be
>  	  used in Secure mode only.
> 
> +config IMX_MBOX
> +	tristate "i.MX Mailbox"
> +	depends on ARCH_MXC || COMPILE_TEST
> +	help
> +	  Mailbox implementation for i.MX Messaging Unit (MU).
> +
>  config PLATFORM_MHU
>  	tristate "Platform MHU Mailbox"
>  	depends on OF
> diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile index
> cc23c3a43fcd..ba2fe1b6dd62 100644
> --- a/drivers/mailbox/Makefile
> +++ b/drivers/mailbox/Makefile
> @@ -7,6 +7,8 @@ obj-$(CONFIG_MAILBOX_TEST)	+= mailbox-test.o
> 
>  obj-$(CONFIG_ARM_MHU)	+= arm_mhu.o
> 
> +obj-$(CONFIG_IMX_MBOX)	+= imx-mailbox.o
> +
>  obj-$(CONFIG_PLATFORM_MHU)	+= platform_mhu.o
> 
>  obj-$(CONFIG_PL320_MBOX)	+= pl320-ipc.o
> diff --git a/drivers/mailbox/imx-mailbox.c b/drivers/mailbox/imx-mailbox.c
> new file mode 100644 index 000000000000..46f2453b144a
> --- /dev/null
> +++ b/drivers/mailbox/imx-mailbox.c
> @@ -0,0 +1,274 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2018 Pengutronix, Oleksij Rempel
> +<o.rempel@pengutronix.de>  */
> +
> +#include <linux/clk.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/mailbox_controller.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +
> +/* Transmit Register */
> +#define IMX_MU_xTRn(x)		(0x00 + 4 * (x))
> +/* Receive Register */
> +#define IMX_MU_xRRn(x)		(0x10 + 4 * (x))
> +/* Status Register */
> +#define IMX_MU_xSR		0x20
> +#define IMX_MU_xSR_TEn(x)	BIT(20 + (3 - (x)))
> +#define IMX_MU_xSR_RFn(x)	BIT(24 + (3 - (x)))
> +#define IMX_MU_xSR_BRDIP	BIT(9)
> +
> +/* Control Register */
> +#define IMX_MU_xCR		0x24
> +/* Transmit Interrupt Enable */
> +#define IMX_MU_xCR_TIEn(x)	BIT(20 + (3 - (x)))
> +/* Receive Interrupt Enable */
> +#define IMX_MU_xCR_RIEn(x)	BIT(24 + (3 - (x)))
> +
> +#define IMX_MU_CHANS	4u
> +
> +struct imx_mu_con_priv {
> +	int			irq;
> +	unsigned int		idx;
> +	char			*irq_desc;
> +};
> +
> +struct imx_mu_priv {
> +	struct device		*dev;
> +	void __iomem		*base;
> +
> +	struct mbox_controller	mbox;
> +	struct mbox_chan	mbox_chans[IMX_MU_CHANS];
> +
> +	struct imx_mu_con_priv  con_priv[IMX_MU_CHANS];
> +	struct clk		*clk;
> +
> +	bool			side_b;
> +};
> +
> +static struct imx_mu_priv *to_imx_mu_priv(struct mbox_controller *mbox)
> +{
> +	return container_of(mbox, struct imx_mu_priv, mbox); }
> +
> +static void imx_mu_write(struct imx_mu_priv *priv, u32 val, u32 offs) {
> +	iowrite32(val, priv->base + offs);
> +}
> +
> +static u32 imx_mu_read(struct imx_mu_priv *priv, u32 offs) {
> +	return ioread32(priv->base + offs);
> +}
> +
> +static u32 imx_mu_rmw(struct imx_mu_priv *priv, u32 offs, u32 set, u32
> +clr) {
> +	u32 val;
> +
> +	val = imx_mu_read(priv, offs);
> +	val &= ~clr;
> +	val |= set;
> +	imx_mu_write(priv, val, offs);
> +
> +	return val;
> +}
> +
> +static irqreturn_t imx_mu_isr(int irq, void *p) {
> +	struct mbox_chan *chan = p;
> +	struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
> +	struct imx_mu_con_priv *cp = chan->con_priv;
> +	u32 val, ctrl, dat;
> +
> +	ctrl = imx_mu_read(priv, IMX_MU_xCR);
> +	val = imx_mu_read(priv, IMX_MU_xSR);
> +	val &= IMX_MU_xSR_TEn(cp->idx) | IMX_MU_xSR_RFn(cp->idx);
> +	val &= ctrl & (IMX_MU_xCR_TIEn(cp->idx) | IMX_MU_xCR_RIEn(cp-
> >idx));
> +	if (!val)
> +		return IRQ_NONE;
> +
> +	if (val & IMX_MU_xSR_TEn(cp->idx)) {
> +		imx_mu_rmw(priv, IMX_MU_xCR, 0, IMX_MU_xCR_TIEn(cp-
> >idx));
> +		mbox_chan_txdone(chan, 0);
> +	}
> +
> +	if (val & IMX_MU_xSR_RFn(cp->idx)) {
> +		dat = imx_mu_read(priv, IMX_MU_xRRn(cp->idx));
> +		mbox_chan_received_data(chan, (void *)&dat);
> +	}
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static bool imx_mu_last_tx_done(struct mbox_chan *chan) {
> +	struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
> +	struct imx_mu_con_priv *cp = chan->con_priv;
> +	u32 val;
> +
> +	val = imx_mu_read(priv, IMX_MU_xSR);
> +	/* test if transmit register is empty */
> +	return val & IMX_MU_xSR_TEn(cp->idx);
> +}
> +
> +static int imx_mu_send_data(struct mbox_chan *chan, void *data) {
> +	struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
> +	struct imx_mu_con_priv *cp = chan->con_priv;
> +	u32 *arg = data;
> +
> +	if (!imx_mu_last_tx_done(chan))
> +		return -EBUSY;
> +
> +	imx_mu_write(priv, *arg, IMX_MU_xTRn(cp->idx));
> +	imx_mu_rmw(priv, IMX_MU_xCR, IMX_MU_xSR_TEn(cp->idx), 0);
> +
> +	return 0;
> +}
> +
> +static int imx_mu_startup(struct mbox_chan *chan) {
> +	struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
> +	struct imx_mu_con_priv *cp = chan->con_priv;
> +	int ret;
> +
> +	cp->irq_desc = devm_kasprintf(priv->dev, GFP_KERNEL,
> "imx_mu_chan[%i]",
> +				      cp->idx);
> +	if (!cp->irq_desc)
> +		return -ENOMEM;
> +
> +	ret = devm_request_irq(priv->dev, cp->irq, imx_mu_isr,
> +			       IRQF_SHARED, cp->irq_desc, chan);
> +	if (ret) {
> +		dev_err(priv->dev,
> +			"Unable to acquire IRQ %d\n", cp->irq);
> +		return ret;
> +	}
> +
> +	imx_mu_rmw(priv, IMX_MU_xCR, IMX_MU_xCR_RIEn(cp->idx), 0);
> +
> +	return 0;
> +}
> +
> +static void imx_mu_shutdown(struct mbox_chan *chan) {
> +	struct imx_mu_priv *priv = to_imx_mu_priv(chan->mbox);
> +	struct imx_mu_con_priv *cp = chan->con_priv;
> +
> +	imx_mu_rmw(priv, IMX_MU_xCR, 0,
> +		   IMX_MU_xCR_TIEn(cp->idx) | IMX_MU_xCR_RIEn(cp-
> >idx));
> +
> +	devm_free_irq(priv->dev, cp->irq, chan);
> +	devm_kfree(priv->dev, cp->irq_desc);
> +}
> +
> +static const struct mbox_chan_ops imx_mu_ops = {
> +	.send_data = imx_mu_send_data,
> +	.startup = imx_mu_startup,
> +	.shutdown = imx_mu_shutdown,
> +};
> +
> +static void imx_mu_init_generic(struct imx_mu_priv *priv) {
> +	if (priv->side_b)
> +		return;
> +
> +	/* Set default MU configuration */
> +	imx_mu_write(priv, 0, IMX_MU_xCR);
> +}
> +
> +static int imx_mu_probe(struct platform_device *pdev) {
> +	struct device *dev = &pdev->dev;
> +	struct device_node *np = dev->of_node;
> +	struct resource *iomem;
> +	struct imx_mu_priv *priv;
> +	unsigned int i;
> +	int irq, ret;
> +
> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	priv->dev = dev;
> +
> +	iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	priv->base = devm_ioremap_resource(&pdev->dev, iomem);
> +	if (IS_ERR(priv->base))
> +		return PTR_ERR(priv->base);
> +
> +	irq = platform_get_irq(pdev, 0);
> +	if (irq < 0)
> +		return irq;
> +
> +	priv->clk = devm_clk_get(dev, NULL);
> +	if (IS_ERR(priv->clk)) {
> +		if (PTR_ERR(priv->clk) != -ENOENT)
> +			return PTR_ERR(priv->clk);
> +
> +		priv->clk = NULL;
> +	}
> +
> +	ret = clk_prepare_enable(priv->clk);
> +	if (ret) {
> +		dev_err(dev, "Failed to enable clock\n");
> +		return ret;
> +	}
> +
> +	for (i = 0; i < IMX_MU_CHANS; i++) {
> +		struct imx_mu_con_priv *cp = &priv->con_priv[i];
> +
> +		cp->idx = i;
> +		cp->irq = irq;
> +		priv->mbox_chans[i].con_priv = cp;
> +	}
> +
> +	if (of_property_read_bool(np, "fsl,mu-side-b"))
> +		priv->side_b = true;
> +
> +	priv->mbox.dev = dev;
> +	priv->mbox.ops = &imx_mu_ops;
> +	priv->mbox.chans = priv->mbox_chans;
> +	priv->mbox.num_chans = IMX_MU_CHANS;
> +	priv->mbox.txdone_irq = true;
> +
> +	platform_set_drvdata(pdev, priv);
> +
> +	imx_mu_init_generic(priv);
> +
> +	return mbox_controller_register(&priv->mbox);
> +}
> +
> +static int imx_mu_remove(struct platform_device *pdev) {
> +	struct imx_mu_priv *priv = platform_get_drvdata(pdev);
> +
> +	mbox_controller_unregister(&priv->mbox);
> +	clk_disable_unprepare(priv->clk);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id imx_mu_dt_ids[] = {
> +	{ .compatible = "fsl,imx6sx-mu" },
> +	{ .compatible = "fsl,imx7s-mu" },

Probably only keep "fsl,imx6sx-mu" is enough.

Otherwise,
Reviewed-by: Dong Aisheng <aisheng.dong@nxp.com>

Regards
Dong Aisheng

> +	{ },
> +};
> +MODULE_DEVICE_TABLE(of, imx_mu_dt_ids);
> +
> +static struct platform_driver imx_mu_driver = {
> +	.probe		= imx_mu_probe,
> +	.remove		= imx_mu_remove,
> +	.driver = {
> +		.name	= "imx_mu",
> +		.of_match_table = imx_mu_dt_ids,
> +	},
> +};
> +module_platform_driver(imx_mu_driver);
> +
> +MODULE_AUTHOR("Oleksij Rempel <o.rempel@pengutronix.de>");
> +MODULE_DESCRIPTION("Message Unit driver for i.MX");
> MODULE_LICENSE("GPL
> +v2");
> --
> 2.18.0