[PATCHv6 0/2] Adding driver for Xilinx LogiCORE IP mailbox.

[PATCHv6 0/2] Adding driver for Xilinx LogiCORE IP mailbox.

[Moritz Fischer]

This patchset adds mailbox framework integration for the Xilinx LogiCORE IP
mailbox.  The Xilinx LogiCORE IP mailbox is a fpga softcore that allows
interprocessor communication between AXI4 stream / memory mapped
processors.

Changes from v5:
- Fixed constness for ops struct
- Removed redundant checks
- Moved ops assignment
- Removed MODULE_ALIAS (since it's untested)

Changes from v4:
- Have separate mbox_ops structs for polling / irq mode
- Moved clk handling to startup / shutdown
- Embedded struct mbox_chan in struct xilinx_mbox
- Fixed mbox-cells in devicetree documentation
- Misc stylistic issues

Changes from v3:
- Stylistic changes
- Changed reg size in dts to 0x100

Changes from v2:
- Fixed error condition for IRQ from >= 0 to > 0
- Fixed clock enable
- Cleaned up docs

Changes from v1:
- Added common clock framework support
- Deal with IRQs that happend before driver load,
  since HW will not let us know about them when we enable IRQs

Changes from v0:
- Several stylistic issues
- Dropped superfluous intr_mode member
- Really masking the IRQs on mailbox_shutdown
- No longer using polling by accident in non-IRQ mode
- Swapped doc and driver commits


Moritz Fischer (2):
  dts: Adding docs for Xilinx LogiCORE IP mailbox driver.
  mailbox: Adding driver for Xilinx LogiCORE IP mailbox.

 .../devicetree/bindings/mailbox/xilinx-mailbox.txt |  44 +++
 MAINTAINERS                                        |   7 +
 drivers/mailbox/Kconfig                            |   8 +
 drivers/mailbox/Makefile                           |   2 +
 drivers/mailbox/mailbox-xilinx.c                   | 367 +++++++++++++++++++++
 5 files changed, 428 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt
 create mode 100644 drivers/mailbox/mailbox-xilinx.c

-- 
2.4.3

[PATCHv6 0/2] Adding driver for Xilinx LogiCORE IP mailbox.

[Moritz Fischer]

This patchset adds mailbox framework integration for the Xilinx LogiCORE IP
mailbox.  The Xilinx LogiCORE IP mailbox is a fpga softcore that allows
interprocessor communication between AXI4 stream / memory mapped
processors.

Changes from v5:
- Fixed constness for ops struct
- Removed redundant checks
- Moved ops assignment
- Removed MODULE_ALIAS (since it's untested)

Changes from v4:
- Have separate mbox_ops structs for polling / irq mode
- Moved clk handling to startup / shutdown
- Embedded struct mbox_chan in struct xilinx_mbox
- Fixed mbox-cells in devicetree documentation
- Misc stylistic issues

Changes from v3:
- Stylistic changes
- Changed reg size in dts to 0x100

Changes from v2:
- Fixed error condition for IRQ from >= 0 to > 0
- Fixed clock enable
- Cleaned up docs

Changes from v1:
- Added common clock framework support
- Deal with IRQs that happend before driver load,
  since HW will not let us know about them when we enable IRQs

Changes from v0:
- Several stylistic issues
- Dropped superfluous intr_mode member
- Really masking the IRQs on mailbox_shutdown
- No longer using polling by accident in non-IRQ mode
- Swapped doc and driver commits


Moritz Fischer (2):
  dts: Adding docs for Xilinx LogiCORE IP mailbox driver.
  mailbox: Adding driver for Xilinx LogiCORE IP mailbox.

 .../devicetree/bindings/mailbox/xilinx-mailbox.txt |  44 +++
 MAINTAINERS                                        |   7 +
 drivers/mailbox/Kconfig                            |   8 +
 drivers/mailbox/Makefile                           |   2 +
 drivers/mailbox/mailbox-xilinx.c                   | 367 +++++++++++++++++++++
 5 files changed, 428 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt
 create mode 100644 drivers/mailbox/mailbox-xilinx.c

-- 
2.4.3

[PATCHv6 1/2] dts: Adding docs for Xilinx LogiCORE IP mailbox driver.

[Moritz Fischer]

Signed-off-by: Moritz Fischer <moritz.fischer@ettus.com>
Acked-by: Michal Simek <michal.simek@xilinx.com>
---
 .../devicetree/bindings/mailbox/xilinx-mailbox.txt | 44 ++++++++++++++++++++++
 1 file changed, 44 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt

diff --git a/Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt b/Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt
new file mode 100644
index 0000000..97b81f8
--- /dev/null
+++ b/Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt
@@ -0,0 +1,44 @@
+Xilinx Mailbox Driver
+=====================
+
+Required properties:
+- compatible       : "xlnx,mailbox-2.1".
+- reg              :  physical base address of the mailbox and length of
+                      memory mapped region.
+- #mbox-cells      :  common mailbox binding property to identify the number
+                      of cells required for the mailbox specifier, should be 0
+- clocks           :  phandle to clock provider
+- clock-names      :  must be 'mbox'
+
+Optional properties:
+- interrupt-parent : interrupt source phandle
+- interrupts       : interrupt number, The interrupt specifier format
+                     depends on the interrupt controller parent.
+
+Example:
+	mbox: mailbox@40400000 {
+		compatible = "xlnx,mailbox-2.1";
+		reg = <0x40400000 0x100>;
+		interrupt-parent = <&intc>;
+		interrupts = <5>;
+		#mbox-cells = <0>;
+		clocks = <&clkc 15>;
+		clock-names = "mbox";
+	};
+
+Mailbox client
+===============
+"mboxes" and the optional "mbox-names" (please see
+Documentation/devicetree/bindings/mailbox/mailbox.txt for details). Each value
+of the mboxes property should contain a phandle to the mailbox controller
+device node and second argument is the channel index. It must be 0 (hardware
+support only one channel). The equivalent "mbox-names" property value can be
+used to give a name to the communication channel to be used by the client user.
+
+Example:
+	mclient0: mclient0@400 {
+		compatible = "client-1.0";
+		reg = <0x400 0x10>;
+		mbox-names = "mbox";
+		mboxes = <&mbox 0>;
+	};
-- 
2.4.3

[PATCHv6 1/2] dts: Adding docs for Xilinx LogiCORE IP mailbox driver.

[Moritz Fischer]

Signed-off-by: Moritz Fischer <moritz.fischer@ettus.com>
Acked-by: Michal Simek <michal.simek@xilinx.com>
---
 .../devicetree/bindings/mailbox/xilinx-mailbox.txt | 44 ++++++++++++++++++++++
 1 file changed, 44 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt

diff --git a/Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt b/Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt
new file mode 100644
index 0000000..97b81f8
--- /dev/null
+++ b/Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt
@@ -0,0 +1,44 @@
+Xilinx Mailbox Driver
+=====================
+
+Required properties:
+- compatible       : "xlnx,mailbox-2.1".
+- reg              :  physical base address of the mailbox and length of
+                      memory mapped region.
+- #mbox-cells      :  common mailbox binding property to identify the number
+                      of cells required for the mailbox specifier, should be 0
+- clocks           :  phandle to clock provider
+- clock-names      :  must be 'mbox'
+
+Optional properties:
+- interrupt-parent : interrupt source phandle
+- interrupts       : interrupt number, The interrupt specifier format
+                     depends on the interrupt controller parent.
+
+Example:
+	mbox: mailbox at 40400000 {
+		compatible = "xlnx,mailbox-2.1";
+		reg = <0x40400000 0x100>;
+		interrupt-parent = <&intc>;
+		interrupts = <5>;
+		#mbox-cells = <0>;
+		clocks = <&clkc 15>;
+		clock-names = "mbox";
+	};
+
+Mailbox client
+===============
+"mboxes" and the optional "mbox-names" (please see
+Documentation/devicetree/bindings/mailbox/mailbox.txt for details). Each value
+of the mboxes property should contain a phandle to the mailbox controller
+device node and second argument is the channel index. It must be 0 (hardware
+support only one channel). The equivalent "mbox-names" property value can be
+used to give a name to the communication channel to be used by the client user.
+
+Example:
+	mclient0: mclient0 at 400 {
+		compatible = "client-1.0";
+		reg = <0x400 0x10>;
+		mbox-names = "mbox";
+		mboxes = <&mbox 0>;
+	};
-- 
2.4.3

[PATCHv6 2/2] mailbox: Adding driver for Xilinx LogiCORE IP mailbox.

[Moritz Fischer]

The Xilinx LogiCORE IP mailbox is a FPGA core that allows for
interprocessor communication via AXI4 memory mapped / AXI4 stream
interfaces.

It is single channel per core and allows for transmit and receive.

Signed-off-by: Moritz Fischer <moritz.fischer@ettus.com>
Acked-by: Michal Simek <michal.simek@xilinx.com>
---
 MAINTAINERS                      |   7 +
 drivers/mailbox/Kconfig          |   8 +
 drivers/mailbox/Makefile         |   2 +
 drivers/mailbox/mailbox-xilinx.c | 367 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 384 insertions(+)
 create mode 100644 drivers/mailbox/mailbox-xilinx.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 4f1e79b..cb88b4a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10998,6 +10998,13 @@ M:	John Linn <John.Linn@xilinx.com>
 S:	Maintained
 F:	drivers/net/ethernet/xilinx/xilinx_axienet*
 
+XILINX MAILBOX DRIVER
+M:	Moritz Fischer <moritz.fischer@ettus.com>
+L:	linux-kernel@vger.kernel.org
+S:	Maintained
+F:	drivers/mailbox/mailbox-xilinx.c
+F:	Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt
+
 XILINX UARTLITE SERIAL DRIVER
 M:	Peter Korsgaard <jacmet@sunsite.dk>
 L:	linux-serial@vger.kernel.org
diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index 84b0a2d..e11e4b2 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig
@@ -60,4 +60,12 @@ config ALTERA_MBOX
 	  An implementation of the Altera Mailbox soft core. It is used
 	  to send message between processors. Say Y here if you want to use the
 	  Altera mailbox support.
+
+config XILINX_MBOX
+	tristate "Xilinx Mailbox"
+	help
+	  An implementation of the Xilinx Mailbox soft core. It is used
+	  to send message between processors. Say Y here if you want to use the
+	  Xilinx mailbox support.
+
 endif
diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
index b18201e..d28a028 100644
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile
@@ -11,3 +11,5 @@ obj-$(CONFIG_OMAP2PLUS_MBOX)	+= omap-mailbox.o
 obj-$(CONFIG_PCC)		+= pcc.o
 
 obj-$(CONFIG_ALTERA_MBOX)	+= mailbox-altera.o
+
+obj-$(CONFIG_XILINX_MBOX)	+= mailbox-xilinx.o
diff --git a/drivers/mailbox/mailbox-xilinx.c b/drivers/mailbox/mailbox-xilinx.c
new file mode 100644
index 0000000..27011e6
--- /dev/null
+++ b/drivers/mailbox/mailbox-xilinx.c
@@ -0,0 +1,367 @@
+/*
+ * Copyright (c) 2015, National Instruments Corp. All rights reserved.
+ *
+ * Driver for the Xilinx LogiCORE mailbox IP block
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/device.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.h>
+#include <linux/platform_device.h>
+
+/* register offsets */
+#define MAILBOX_REG_WRDATA	0x00
+#define MAILBOX_REG_RDDATA	0x08
+#define MAILBOX_REG_STATUS	0x10
+#define MAILBOX_REG_ERROR	0x14
+#define MAILBOX_REG_SIT	0x18
+#define MAILBOX_REG_RIT	0x1c
+#define MAILBOX_REG_IS	0x20
+#define MAILBOX_REG_IE	0x24
+#define MAILBOX_REG_IP	0x28
+
+/* status register */
+#define STS_RTA	BIT(3)
+#define STS_STA	BIT(2)
+#define STS_FULL	BIT(1)
+#define STS_EMPTY	BIT(0)
+
+/* error register */
+#define ERR_FULL	BIT(1)
+#define ERR_EMPTY	BIT(0)
+
+/* mailbox interrupt status register */
+#define INT_STATUS_ERR	BIT(2)
+#define INT_STATUS_RTI	BIT(1)
+#define INT_STATUS_STI	BIT(0)
+
+/* mailbox interrupt enable register */
+#define INT_ENABLE_ERR	BIT(2)
+#define INT_ENABLE_RTI	BIT(1)
+#define INT_ENABLE_STI	BIT(0)
+
+#define MBOX_POLLING_MS		5	/* polling interval 5ms */
+
+struct xilinx_mbox {
+	int irq;
+	void __iomem *mbox_base;
+	struct clk *clk;
+	struct device *dev;
+	struct mbox_controller controller;
+	struct mbox_chan chan;
+
+	/* if the controller supports only RX polling mode */
+	struct timer_list rxpoll_timer;
+};
+
+static struct xilinx_mbox *mbox_chan_to_xilinx_mbox(struct mbox_chan *chan)
+{
+	return container_of(chan, struct xilinx_mbox, chan);
+}
+
+static inline bool xilinx_mbox_full(struct xilinx_mbox *mbox)
+{
+	u32 status;
+
+	status = readl_relaxed(mbox->mbox_base + MAILBOX_REG_STATUS);
+
+	return status & STS_FULL;
+}
+
+static inline bool xilinx_mbox_pending(struct xilinx_mbox *mbox)
+{
+	u32 status;
+
+	status = readl_relaxed(mbox->mbox_base + MAILBOX_REG_STATUS);
+
+	return !(status & STS_EMPTY);
+}
+
+static void xilinx_mbox_intmask(struct xilinx_mbox *mbox, u32 mask, bool enable)
+{
+	u32 mask_reg;
+
+	mask_reg = readl_relaxed(mbox->mbox_base + MAILBOX_REG_IE);
+	if (enable)
+		mask_reg |= mask;
+	else
+		mask_reg &= ~mask;
+
+	writel_relaxed(mask_reg, mbox->mbox_base + MAILBOX_REG_IE);
+}
+
+static inline void xilinx_mbox_rx_intmask(struct xilinx_mbox *mbox, bool enable)
+{
+	xilinx_mbox_intmask(mbox, INT_ENABLE_RTI, enable);
+}
+
+static inline void xilinx_mbox_tx_intmask(struct xilinx_mbox *mbox, bool enable)
+{
+	xilinx_mbox_intmask(mbox, INT_ENABLE_STI, enable);
+}
+
+static void xilinx_mbox_rx_data(struct mbox_chan *chan)
+{
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+	u32 data;
+
+	if (xilinx_mbox_pending(mbox)) {
+		data = readl_relaxed(mbox->mbox_base + MAILBOX_REG_RDDATA);
+		mbox_chan_received_data(chan, (void *)data);
+	}
+}
+
+static void xilinx_mbox_poll_rx(unsigned long data)
+{
+	struct mbox_chan *chan = (struct mbox_chan *)data;
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+
+	xilinx_mbox_rx_data(chan);
+
+	mod_timer(&mbox->rxpoll_timer,
+		  jiffies + msecs_to_jiffies(MBOX_POLLING_MS));
+}
+
+static irqreturn_t xilinx_mbox_interrupt(int irq, void *p)
+{
+	u32 mask;
+	struct mbox_chan *chan = (struct mbox_chan *)p;
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+
+	mask = readl_relaxed(mbox->mbox_base + MAILBOX_REG_IS);
+	if (mask & INT_STATUS_RTI)
+		xilinx_mbox_rx_data(chan);
+
+	/* mask irqs *before* notifying done, require tx_block=true */
+	if (mask & INT_STATUS_STI) {
+		xilinx_mbox_tx_intmask(mbox, false);
+		mbox_chan_txdone(chan, 0);
+	}
+
+	writel_relaxed(mask, mbox->mbox_base + MAILBOX_REG_IS);
+
+	return IRQ_HANDLED;
+}
+
+static int xilinx_mbox_irq_startup(struct mbox_chan *chan)
+{
+	int ret;
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+
+	ret = request_irq(mbox->irq, xilinx_mbox_interrupt, 0,
+			  dev_name(mbox->dev), chan);
+	if (unlikely(ret)) {
+		dev_err(mbox->dev,
+			"failed to register mailbox interrupt:%d\n",
+			ret);
+		return ret;
+	}
+
+	/* prep and enable the clock */
+	clk_prepare_enable(mbox->clk);
+
+	xilinx_mbox_rx_intmask(mbox, true);
+
+	/* if fifo was full already, we didn't get an interrupt */
+	while (xilinx_mbox_pending(mbox))
+		xilinx_mbox_rx_data(chan);
+
+	return 0;
+}
+
+static int xilinx_mbox_poll_startup(struct mbox_chan *chan)
+{
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+
+	clk_prepare_enable(mbox->clk);
+
+	mod_timer(&mbox->rxpoll_timer,
+		  jiffies + msecs_to_jiffies(MBOX_POLLING_MS));
+
+	return 0;
+}
+
+static int xilinx_mbox_irq_send_data(struct mbox_chan *chan, void *data)
+{
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+	u32 *udata = data;
+
+	if (xilinx_mbox_full(mbox))
+		return -EBUSY;
+
+	/* enable interrupt before send */
+	xilinx_mbox_tx_intmask(mbox, true);
+
+	writel_relaxed(*udata, mbox->mbox_base + MAILBOX_REG_WRDATA);
+
+	return 0;
+}
+
+static int xilinx_mbox_poll_send_data(struct mbox_chan *chan, void *data)
+{
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+	u32 *udata = data;
+
+	if (!mbox || !data)
+		return -EINVAL;
+
+	if (xilinx_mbox_full(mbox))
+		return -EBUSY;
+
+	writel_relaxed(*udata, mbox->mbox_base + MAILBOX_REG_WRDATA);
+
+	return 0;
+}
+
+static bool xilinx_mbox_last_tx_done(struct mbox_chan *chan)
+{
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+
+	/* return false if mailbox is full */
+	return !xilinx_mbox_full(mbox);
+}
+
+static bool xilinx_mbox_peek_data(struct mbox_chan *chan)
+{
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+
+	return xilinx_mbox_pending(mbox);
+}
+
+static void xilinx_mbox_irq_shutdown(struct mbox_chan *chan)
+{
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+
+	/* mask all interrupts */
+	writel_relaxed(0, mbox->mbox_base + MAILBOX_REG_IE);
+
+	clk_disable_unprepare(mbox->clk);
+
+	free_irq(mbox->irq, chan);
+}
+
+static void xilinx_mbox_poll_shutdown(struct mbox_chan *chan)
+{
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+
+	del_timer_sync(&mbox->rxpoll_timer);
+
+	clk_disable_unprepare(mbox->clk);
+}
+
+static const struct mbox_chan_ops xilinx_mbox_irq_ops = {
+	.send_data = xilinx_mbox_irq_send_data,
+	.startup = xilinx_mbox_irq_startup,
+	.shutdown = xilinx_mbox_irq_shutdown,
+	.last_tx_done = xilinx_mbox_last_tx_done,
+	.peek_data = xilinx_mbox_peek_data,
+};
+
+static const struct mbox_chan_ops xilinx_mbox_poll_ops = {
+	.send_data = xilinx_mbox_poll_send_data,
+	.startup = xilinx_mbox_poll_startup,
+	.shutdown = xilinx_mbox_poll_shutdown,
+	.last_tx_done = xilinx_mbox_last_tx_done,
+	.peek_data = xilinx_mbox_peek_data,
+};
+
+static int xilinx_mbox_probe(struct platform_device *pdev)
+{
+	struct xilinx_mbox *mbox;
+	struct resource	*regs;
+	int ret;
+
+	mbox = devm_kzalloc(&pdev->dev, sizeof(*mbox), GFP_KERNEL);
+	if (!mbox)
+		return -ENOMEM;
+
+	/* get clk and enable */
+	mbox->clk = devm_clk_get(&pdev->dev, "mbox");
+	if (IS_ERR(mbox->clk)) {
+		dev_err(&pdev->dev, "Couldn't get clk.\n");
+		return PTR_ERR(mbox->clk);
+	}
+
+	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
+	mbox->mbox_base = devm_ioremap_resource(&pdev->dev, regs);
+	if (IS_ERR(mbox->mbox_base))
+		return PTR_ERR(mbox->mbox_base);
+
+	mbox->irq = platform_get_irq(pdev, 0);
+	/* if irq is present, we can use it, otherwise, poll */
+	if (mbox->irq > 0) {
+		mbox->controller.txdone_irq = true;
+		mbox->controller.ops = &xilinx_mbox_irq_ops;
+	} else {
+		dev_info(&pdev->dev, "IRQ not found, fallback to polling.\n");
+		mbox->controller.txdone_poll = true;
+		mbox->controller.txpoll_period = MBOX_POLLING_MS;
+		mbox->controller.ops = &xilinx_mbox_poll_ops;
+
+		setup_timer(&mbox->rxpoll_timer, xilinx_mbox_poll_rx,
+			    (unsigned long)&mbox->chan);
+	}
+
+	mbox->dev = &pdev->dev;
+
+	/* hardware supports only one channel. */
+	mbox->controller.dev = mbox->dev;
+	mbox->controller.num_chans = 1;
+	mbox->controller.chans = &mbox->chan;
+
+	ret = mbox_controller_register(&mbox->controller);
+	if (ret) {
+		dev_err(&pdev->dev, "Register mailbox failed\n");
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, mbox);
+
+	return 0;
+}
+
+static int xilinx_mbox_remove(struct platform_device *pdev)
+{
+	struct xilinx_mbox *mbox = platform_get_drvdata(pdev);
+
+	mbox_controller_unregister(&mbox->controller);
+
+	return 0;
+}
+
+static const struct of_device_id xilinx_mbox_match[] = {
+	{ .compatible = "xlnx,mailbox-2.1" },
+	{ /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, xilinx_mbox_match);
+
+static struct platform_driver xilinx_mbox_driver = {
+	.probe	= xilinx_mbox_probe,
+	.remove	= xilinx_mbox_remove,
+	.driver	= {
+		.name	= KBUILD_MODNAME,
+		.of_match_table	= xilinx_mbox_match,
+	},
+};
+
+module_platform_driver(xilinx_mbox_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Xilinx mailbox specific functions");
+MODULE_AUTHOR("Moritz Fischer <moritz.fischer@ettus.com>");
-- 
2.4.3

[PATCHv6 2/2] mailbox: Adding driver for Xilinx LogiCORE IP mailbox.

[Moritz Fischer]

The Xilinx LogiCORE IP mailbox is a FPGA core that allows for
interprocessor communication via AXI4 memory mapped / AXI4 stream
interfaces.

It is single channel per core and allows for transmit and receive.

Signed-off-by: Moritz Fischer <moritz.fischer-+aYTwkv1SeIAvxtiuMwx3w@public.gmane.org>
Acked-by: Michal Simek <michal.simek-gjFFaj9aHVfQT0dZR+AlfA@public.gmane.org>
---
 MAINTAINERS                      |   7 +
 drivers/mailbox/Kconfig          |   8 +
 drivers/mailbox/Makefile         |   2 +
 drivers/mailbox/mailbox-xilinx.c | 367 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 384 insertions(+)
 create mode 100644 drivers/mailbox/mailbox-xilinx.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 4f1e79b..cb88b4a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10998,6 +10998,13 @@ M:	John Linn <John.Linn-gjFFaj9aHVfQT0dZR+AlfA@public.gmane.org>
 S:	Maintained
 F:	drivers/net/ethernet/xilinx/xilinx_axienet*
 
+XILINX MAILBOX DRIVER
+M:	Moritz Fischer <moritz.fischer-+aYTwkv1SeIAvxtiuMwx3w@public.gmane.org>
+L:	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
+S:	Maintained
+F:	drivers/mailbox/mailbox-xilinx.c
+F:	Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt
+
 XILINX UARTLITE SERIAL DRIVER
 M:	Peter Korsgaard <jacmet-OfajU3CKLf1/SzgSGea1oA@public.gmane.org>
 L:	linux-serial-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index 84b0a2d..e11e4b2 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig
@@ -60,4 +60,12 @@ config ALTERA_MBOX
 	  An implementation of the Altera Mailbox soft core. It is used
 	  to send message between processors. Say Y here if you want to use the
 	  Altera mailbox support.
+
+config XILINX_MBOX
+	tristate "Xilinx Mailbox"
+	help
+	  An implementation of the Xilinx Mailbox soft core. It is used
+	  to send message between processors. Say Y here if you want to use the
+	  Xilinx mailbox support.
+
 endif
diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
index b18201e..d28a028 100644
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile
@@ -11,3 +11,5 @@ obj-$(CONFIG_OMAP2PLUS_MBOX)	+= omap-mailbox.o
 obj-$(CONFIG_PCC)		+= pcc.o
 
 obj-$(CONFIG_ALTERA_MBOX)	+= mailbox-altera.o
+
+obj-$(CONFIG_XILINX_MBOX)	+= mailbox-xilinx.o
diff --git a/drivers/mailbox/mailbox-xilinx.c b/drivers/mailbox/mailbox-xilinx.c
new file mode 100644
index 0000000..27011e6
--- /dev/null
+++ b/drivers/mailbox/mailbox-xilinx.c
@@ -0,0 +1,367 @@
+/*
+ * Copyright (c) 2015, National Instruments Corp. All rights reserved.
+ *
+ * Driver for the Xilinx LogiCORE mailbox IP block
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/device.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.h>
+#include <linux/platform_device.h>
+
+/* register offsets */
+#define MAILBOX_REG_WRDATA	0x00
+#define MAILBOX_REG_RDDATA	0x08
+#define MAILBOX_REG_STATUS	0x10
+#define MAILBOX_REG_ERROR	0x14
+#define MAILBOX_REG_SIT	0x18
+#define MAILBOX_REG_RIT	0x1c
+#define MAILBOX_REG_IS	0x20
+#define MAILBOX_REG_IE	0x24
+#define MAILBOX_REG_IP	0x28
+
+/* status register */
+#define STS_RTA	BIT(3)
+#define STS_STA	BIT(2)
+#define STS_FULL	BIT(1)
+#define STS_EMPTY	BIT(0)
+
+/* error register */
+#define ERR_FULL	BIT(1)
+#define ERR_EMPTY	BIT(0)
+
+/* mailbox interrupt status register */
+#define INT_STATUS_ERR	BIT(2)
+#define INT_STATUS_RTI	BIT(1)
+#define INT_STATUS_STI	BIT(0)
+
+/* mailbox interrupt enable register */
+#define INT_ENABLE_ERR	BIT(2)
+#define INT_ENABLE_RTI	BIT(1)
+#define INT_ENABLE_STI	BIT(0)
+
+#define MBOX_POLLING_MS		5	/* polling interval 5ms */
+
+struct xilinx_mbox {
+	int irq;
+	void __iomem *mbox_base;
+	struct clk *clk;
+	struct device *dev;
+	struct mbox_controller controller;
+	struct mbox_chan chan;
+
+	/* if the controller supports only RX polling mode */
+	struct timer_list rxpoll_timer;
+};
+
+static struct xilinx_mbox *mbox_chan_to_xilinx_mbox(struct mbox_chan *chan)
+{
+	return container_of(chan, struct xilinx_mbox, chan);
+}
+
+static inline bool xilinx_mbox_full(struct xilinx_mbox *mbox)
+{
+	u32 status;
+
+	status = readl_relaxed(mbox->mbox_base + MAILBOX_REG_STATUS);
+
+	return status & STS_FULL;
+}
+
+static inline bool xilinx_mbox_pending(struct xilinx_mbox *mbox)
+{
+	u32 status;
+
+	status = readl_relaxed(mbox->mbox_base + MAILBOX_REG_STATUS);
+
+	return !(status & STS_EMPTY);
+}
+
+static void xilinx_mbox_intmask(struct xilinx_mbox *mbox, u32 mask, bool enable)
+{
+	u32 mask_reg;
+
+	mask_reg = readl_relaxed(mbox->mbox_base + MAILBOX_REG_IE);
+	if (enable)
+		mask_reg |= mask;
+	else
+		mask_reg &= ~mask;
+
+	writel_relaxed(mask_reg, mbox->mbox_base + MAILBOX_REG_IE);
+}
+
+static inline void xilinx_mbox_rx_intmask(struct xilinx_mbox *mbox, bool enable)
+{
+	xilinx_mbox_intmask(mbox, INT_ENABLE_RTI, enable);
+}
+
+static inline void xilinx_mbox_tx_intmask(struct xilinx_mbox *mbox, bool enable)
+{
+	xilinx_mbox_intmask(mbox, INT_ENABLE_STI, enable);
+}
+
+static void xilinx_mbox_rx_data(struct mbox_chan *chan)
+{
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+	u32 data;
+
+	if (xilinx_mbox_pending(mbox)) {
+		data = readl_relaxed(mbox->mbox_base + MAILBOX_REG_RDDATA);
+		mbox_chan_received_data(chan, (void *)data);
+	}
+}
+
+static void xilinx_mbox_poll_rx(unsigned long data)
+{
+	struct mbox_chan *chan = (struct mbox_chan *)data;
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+
+	xilinx_mbox_rx_data(chan);
+
+	mod_timer(&mbox->rxpoll_timer,
+		  jiffies + msecs_to_jiffies(MBOX_POLLING_MS));
+}
+
+static irqreturn_t xilinx_mbox_interrupt(int irq, void *p)
+{
+	u32 mask;
+	struct mbox_chan *chan = (struct mbox_chan *)p;
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+
+	mask = readl_relaxed(mbox->mbox_base + MAILBOX_REG_IS);
+	if (mask & INT_STATUS_RTI)
+		xilinx_mbox_rx_data(chan);
+
+	/* mask irqs *before* notifying done, require tx_block=true */
+	if (mask & INT_STATUS_STI) {
+		xilinx_mbox_tx_intmask(mbox, false);
+		mbox_chan_txdone(chan, 0);
+	}
+
+	writel_relaxed(mask, mbox->mbox_base + MAILBOX_REG_IS);
+
+	return IRQ_HANDLED;
+}
+
+static int xilinx_mbox_irq_startup(struct mbox_chan *chan)
+{
+	int ret;
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+
+	ret = request_irq(mbox->irq, xilinx_mbox_interrupt, 0,
+			  dev_name(mbox->dev), chan);
+	if (unlikely(ret)) {
+		dev_err(mbox->dev,
+			"failed to register mailbox interrupt:%d\n",
+			ret);
+		return ret;
+	}
+
+	/* prep and enable the clock */
+	clk_prepare_enable(mbox->clk);
+
+	xilinx_mbox_rx_intmask(mbox, true);
+
+	/* if fifo was full already, we didn't get an interrupt */
+	while (xilinx_mbox_pending(mbox))
+		xilinx_mbox_rx_data(chan);
+
+	return 0;
+}
+
+static int xilinx_mbox_poll_startup(struct mbox_chan *chan)
+{
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+
+	clk_prepare_enable(mbox->clk);
+
+	mod_timer(&mbox->rxpoll_timer,
+		  jiffies + msecs_to_jiffies(MBOX_POLLING_MS));
+
+	return 0;
+}
+
+static int xilinx_mbox_irq_send_data(struct mbox_chan *chan, void *data)
+{
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+	u32 *udata = data;
+
+	if (xilinx_mbox_full(mbox))
+		return -EBUSY;
+
+	/* enable interrupt before send */
+	xilinx_mbox_tx_intmask(mbox, true);
+
+	writel_relaxed(*udata, mbox->mbox_base + MAILBOX_REG_WRDATA);
+
+	return 0;
+}
+
+static int xilinx_mbox_poll_send_data(struct mbox_chan *chan, void *data)
+{
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+	u32 *udata = data;
+
+	if (!mbox || !data)
+		return -EINVAL;
+
+	if (xilinx_mbox_full(mbox))
+		return -EBUSY;
+
+	writel_relaxed(*udata, mbox->mbox_base + MAILBOX_REG_WRDATA);
+
+	return 0;
+}
+
+static bool xilinx_mbox_last_tx_done(struct mbox_chan *chan)
+{
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+
+	/* return false if mailbox is full */
+	return !xilinx_mbox_full(mbox);
+}
+
+static bool xilinx_mbox_peek_data(struct mbox_chan *chan)
+{
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+
+	return xilinx_mbox_pending(mbox);
+}
+
+static void xilinx_mbox_irq_shutdown(struct mbox_chan *chan)
+{
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+
+	/* mask all interrupts */
+	writel_relaxed(0, mbox->mbox_base + MAILBOX_REG_IE);
+
+	clk_disable_unprepare(mbox->clk);
+
+	free_irq(mbox->irq, chan);
+}
+
+static void xilinx_mbox_poll_shutdown(struct mbox_chan *chan)
+{
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+
+	del_timer_sync(&mbox->rxpoll_timer);
+
+	clk_disable_unprepare(mbox->clk);
+}
+
+static const struct mbox_chan_ops xilinx_mbox_irq_ops = {
+	.send_data = xilinx_mbox_irq_send_data,
+	.startup = xilinx_mbox_irq_startup,
+	.shutdown = xilinx_mbox_irq_shutdown,
+	.last_tx_done = xilinx_mbox_last_tx_done,
+	.peek_data = xilinx_mbox_peek_data,
+};
+
+static const struct mbox_chan_ops xilinx_mbox_poll_ops = {
+	.send_data = xilinx_mbox_poll_send_data,
+	.startup = xilinx_mbox_poll_startup,
+	.shutdown = xilinx_mbox_poll_shutdown,
+	.last_tx_done = xilinx_mbox_last_tx_done,
+	.peek_data = xilinx_mbox_peek_data,
+};
+
+static int xilinx_mbox_probe(struct platform_device *pdev)
+{
+	struct xilinx_mbox *mbox;
+	struct resource	*regs;
+	int ret;
+
+	mbox = devm_kzalloc(&pdev->dev, sizeof(*mbox), GFP_KERNEL);
+	if (!mbox)
+		return -ENOMEM;
+
+	/* get clk and enable */
+	mbox->clk = devm_clk_get(&pdev->dev, "mbox");
+	if (IS_ERR(mbox->clk)) {
+		dev_err(&pdev->dev, "Couldn't get clk.\n");
+		return PTR_ERR(mbox->clk);
+	}
+
+	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
+	mbox->mbox_base = devm_ioremap_resource(&pdev->dev, regs);
+	if (IS_ERR(mbox->mbox_base))
+		return PTR_ERR(mbox->mbox_base);
+
+	mbox->irq = platform_get_irq(pdev, 0);
+	/* if irq is present, we can use it, otherwise, poll */
+	if (mbox->irq > 0) {
+		mbox->controller.txdone_irq = true;
+		mbox->controller.ops = &xilinx_mbox_irq_ops;
+	} else {
+		dev_info(&pdev->dev, "IRQ not found, fallback to polling.\n");
+		mbox->controller.txdone_poll = true;
+		mbox->controller.txpoll_period = MBOX_POLLING_MS;
+		mbox->controller.ops = &xilinx_mbox_poll_ops;
+
+		setup_timer(&mbox->rxpoll_timer, xilinx_mbox_poll_rx,
+			    (unsigned long)&mbox->chan);
+	}
+
+	mbox->dev = &pdev->dev;
+
+	/* hardware supports only one channel. */
+	mbox->controller.dev = mbox->dev;
+	mbox->controller.num_chans = 1;
+	mbox->controller.chans = &mbox->chan;
+
+	ret = mbox_controller_register(&mbox->controller);
+	if (ret) {
+		dev_err(&pdev->dev, "Register mailbox failed\n");
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, mbox);
+
+	return 0;
+}
+
+static int xilinx_mbox_remove(struct platform_device *pdev)
+{
+	struct xilinx_mbox *mbox = platform_get_drvdata(pdev);
+
+	mbox_controller_unregister(&mbox->controller);
+
+	return 0;
+}
+
+static const struct of_device_id xilinx_mbox_match[] = {
+	{ .compatible = "xlnx,mailbox-2.1" },
+	{ /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, xilinx_mbox_match);
+
+static struct platform_driver xilinx_mbox_driver = {
+	.probe	= xilinx_mbox_probe,
+	.remove	= xilinx_mbox_remove,
+	.driver	= {
+		.name	= KBUILD_MODNAME,
+		.of_match_table	= xilinx_mbox_match,
+	},
+};
+
+module_platform_driver(xilinx_mbox_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Xilinx mailbox specific functions");
+MODULE_AUTHOR("Moritz Fischer <moritz.fischer-+aYTwkv1SeIAvxtiuMwx3w@public.gmane.org>");
-- 
2.4.3

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[PATCHv6 2/2] mailbox: Adding driver for Xilinx LogiCORE IP mailbox.

[Moritz Fischer]

The Xilinx LogiCORE IP mailbox is a FPGA core that allows for
interprocessor communication via AXI4 memory mapped / AXI4 stream
interfaces.

It is single channel per core and allows for transmit and receive.

Signed-off-by: Moritz Fischer <moritz.fischer@ettus.com>
Acked-by: Michal Simek <michal.simek@xilinx.com>
---
 MAINTAINERS                      |   7 +
 drivers/mailbox/Kconfig          |   8 +
 drivers/mailbox/Makefile         |   2 +
 drivers/mailbox/mailbox-xilinx.c | 367 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 384 insertions(+)
 create mode 100644 drivers/mailbox/mailbox-xilinx.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 4f1e79b..cb88b4a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10998,6 +10998,13 @@ M:	John Linn <John.Linn@xilinx.com>
 S:	Maintained
 F:	drivers/net/ethernet/xilinx/xilinx_axienet*
 
+XILINX MAILBOX DRIVER
+M:	Moritz Fischer <moritz.fischer@ettus.com>
+L:	linux-kernel at vger.kernel.org
+S:	Maintained
+F:	drivers/mailbox/mailbox-xilinx.c
+F:	Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt
+
 XILINX UARTLITE SERIAL DRIVER
 M:	Peter Korsgaard <jacmet@sunsite.dk>
 L:	linux-serial at vger.kernel.org
diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index 84b0a2d..e11e4b2 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig
@@ -60,4 +60,12 @@ config ALTERA_MBOX
 	  An implementation of the Altera Mailbox soft core. It is used
 	  to send message between processors. Say Y here if you want to use the
 	  Altera mailbox support.
+
+config XILINX_MBOX
+	tristate "Xilinx Mailbox"
+	help
+	  An implementation of the Xilinx Mailbox soft core. It is used
+	  to send message between processors. Say Y here if you want to use the
+	  Xilinx mailbox support.
+
 endif
diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
index b18201e..d28a028 100644
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile
@@ -11,3 +11,5 @@ obj-$(CONFIG_OMAP2PLUS_MBOX)	+= omap-mailbox.o
 obj-$(CONFIG_PCC)		+= pcc.o
 
 obj-$(CONFIG_ALTERA_MBOX)	+= mailbox-altera.o
+
+obj-$(CONFIG_XILINX_MBOX)	+= mailbox-xilinx.o
diff --git a/drivers/mailbox/mailbox-xilinx.c b/drivers/mailbox/mailbox-xilinx.c
new file mode 100644
index 0000000..27011e6
--- /dev/null
+++ b/drivers/mailbox/mailbox-xilinx.c
@@ -0,0 +1,367 @@
+/*
+ * Copyright (c) 2015, National Instruments Corp. All rights reserved.
+ *
+ * Driver for the Xilinx LogiCORE mailbox IP block
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/device.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.h>
+#include <linux/platform_device.h>
+
+/* register offsets */
+#define MAILBOX_REG_WRDATA	0x00
+#define MAILBOX_REG_RDDATA	0x08
+#define MAILBOX_REG_STATUS	0x10
+#define MAILBOX_REG_ERROR	0x14
+#define MAILBOX_REG_SIT	0x18
+#define MAILBOX_REG_RIT	0x1c
+#define MAILBOX_REG_IS	0x20
+#define MAILBOX_REG_IE	0x24
+#define MAILBOX_REG_IP	0x28
+
+/* status register */
+#define STS_RTA	BIT(3)
+#define STS_STA	BIT(2)
+#define STS_FULL	BIT(1)
+#define STS_EMPTY	BIT(0)
+
+/* error register */
+#define ERR_FULL	BIT(1)
+#define ERR_EMPTY	BIT(0)
+
+/* mailbox interrupt status register */
+#define INT_STATUS_ERR	BIT(2)
+#define INT_STATUS_RTI	BIT(1)
+#define INT_STATUS_STI	BIT(0)
+
+/* mailbox interrupt enable register */
+#define INT_ENABLE_ERR	BIT(2)
+#define INT_ENABLE_RTI	BIT(1)
+#define INT_ENABLE_STI	BIT(0)
+
+#define MBOX_POLLING_MS		5	/* polling interval 5ms */
+
+struct xilinx_mbox {
+	int irq;
+	void __iomem *mbox_base;
+	struct clk *clk;
+	struct device *dev;
+	struct mbox_controller controller;
+	struct mbox_chan chan;
+
+	/* if the controller supports only RX polling mode */
+	struct timer_list rxpoll_timer;
+};
+
+static struct xilinx_mbox *mbox_chan_to_xilinx_mbox(struct mbox_chan *chan)
+{
+	return container_of(chan, struct xilinx_mbox, chan);
+}
+
+static inline bool xilinx_mbox_full(struct xilinx_mbox *mbox)
+{
+	u32 status;
+
+	status = readl_relaxed(mbox->mbox_base + MAILBOX_REG_STATUS);
+
+	return status & STS_FULL;
+}
+
+static inline bool xilinx_mbox_pending(struct xilinx_mbox *mbox)
+{
+	u32 status;
+
+	status = readl_relaxed(mbox->mbox_base + MAILBOX_REG_STATUS);
+
+	return !(status & STS_EMPTY);
+}
+
+static void xilinx_mbox_intmask(struct xilinx_mbox *mbox, u32 mask, bool enable)
+{
+	u32 mask_reg;
+
+	mask_reg = readl_relaxed(mbox->mbox_base + MAILBOX_REG_IE);
+	if (enable)
+		mask_reg |= mask;
+	else
+		mask_reg &= ~mask;
+
+	writel_relaxed(mask_reg, mbox->mbox_base + MAILBOX_REG_IE);
+}
+
+static inline void xilinx_mbox_rx_intmask(struct xilinx_mbox *mbox, bool enable)
+{
+	xilinx_mbox_intmask(mbox, INT_ENABLE_RTI, enable);
+}
+
+static inline void xilinx_mbox_tx_intmask(struct xilinx_mbox *mbox, bool enable)
+{
+	xilinx_mbox_intmask(mbox, INT_ENABLE_STI, enable);
+}
+
+static void xilinx_mbox_rx_data(struct mbox_chan *chan)
+{
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+	u32 data;
+
+	if (xilinx_mbox_pending(mbox)) {
+		data = readl_relaxed(mbox->mbox_base + MAILBOX_REG_RDDATA);
+		mbox_chan_received_data(chan, (void *)data);
+	}
+}
+
+static void xilinx_mbox_poll_rx(unsigned long data)
+{
+	struct mbox_chan *chan = (struct mbox_chan *)data;
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+
+	xilinx_mbox_rx_data(chan);
+
+	mod_timer(&mbox->rxpoll_timer,
+		  jiffies + msecs_to_jiffies(MBOX_POLLING_MS));
+}
+
+static irqreturn_t xilinx_mbox_interrupt(int irq, void *p)
+{
+	u32 mask;
+	struct mbox_chan *chan = (struct mbox_chan *)p;
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+
+	mask = readl_relaxed(mbox->mbox_base + MAILBOX_REG_IS);
+	if (mask & INT_STATUS_RTI)
+		xilinx_mbox_rx_data(chan);
+
+	/* mask irqs *before* notifying done, require tx_block=true */
+	if (mask & INT_STATUS_STI) {
+		xilinx_mbox_tx_intmask(mbox, false);
+		mbox_chan_txdone(chan, 0);
+	}
+
+	writel_relaxed(mask, mbox->mbox_base + MAILBOX_REG_IS);
+
+	return IRQ_HANDLED;
+}
+
+static int xilinx_mbox_irq_startup(struct mbox_chan *chan)
+{
+	int ret;
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+
+	ret = request_irq(mbox->irq, xilinx_mbox_interrupt, 0,
+			  dev_name(mbox->dev), chan);
+	if (unlikely(ret)) {
+		dev_err(mbox->dev,
+			"failed to register mailbox interrupt:%d\n",
+			ret);
+		return ret;
+	}
+
+	/* prep and enable the clock */
+	clk_prepare_enable(mbox->clk);
+
+	xilinx_mbox_rx_intmask(mbox, true);
+
+	/* if fifo was full already, we didn't get an interrupt */
+	while (xilinx_mbox_pending(mbox))
+		xilinx_mbox_rx_data(chan);
+
+	return 0;
+}
+
+static int xilinx_mbox_poll_startup(struct mbox_chan *chan)
+{
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+
+	clk_prepare_enable(mbox->clk);
+
+	mod_timer(&mbox->rxpoll_timer,
+		  jiffies + msecs_to_jiffies(MBOX_POLLING_MS));
+
+	return 0;
+}
+
+static int xilinx_mbox_irq_send_data(struct mbox_chan *chan, void *data)
+{
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+	u32 *udata = data;
+
+	if (xilinx_mbox_full(mbox))
+		return -EBUSY;
+
+	/* enable interrupt before send */
+	xilinx_mbox_tx_intmask(mbox, true);
+
+	writel_relaxed(*udata, mbox->mbox_base + MAILBOX_REG_WRDATA);
+
+	return 0;
+}
+
+static int xilinx_mbox_poll_send_data(struct mbox_chan *chan, void *data)
+{
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+	u32 *udata = data;
+
+	if (!mbox || !data)
+		return -EINVAL;
+
+	if (xilinx_mbox_full(mbox))
+		return -EBUSY;
+
+	writel_relaxed(*udata, mbox->mbox_base + MAILBOX_REG_WRDATA);
+
+	return 0;
+}
+
+static bool xilinx_mbox_last_tx_done(struct mbox_chan *chan)
+{
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+
+	/* return false if mailbox is full */
+	return !xilinx_mbox_full(mbox);
+}
+
+static bool xilinx_mbox_peek_data(struct mbox_chan *chan)
+{
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+
+	return xilinx_mbox_pending(mbox);
+}
+
+static void xilinx_mbox_irq_shutdown(struct mbox_chan *chan)
+{
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+
+	/* mask all interrupts */
+	writel_relaxed(0, mbox->mbox_base + MAILBOX_REG_IE);
+
+	clk_disable_unprepare(mbox->clk);
+
+	free_irq(mbox->irq, chan);
+}
+
+static void xilinx_mbox_poll_shutdown(struct mbox_chan *chan)
+{
+	struct xilinx_mbox *mbox = mbox_chan_to_xilinx_mbox(chan);
+
+	del_timer_sync(&mbox->rxpoll_timer);
+
+	clk_disable_unprepare(mbox->clk);
+}
+
+static const struct mbox_chan_ops xilinx_mbox_irq_ops = {
+	.send_data = xilinx_mbox_irq_send_data,
+	.startup = xilinx_mbox_irq_startup,
+	.shutdown = xilinx_mbox_irq_shutdown,
+	.last_tx_done = xilinx_mbox_last_tx_done,
+	.peek_data = xilinx_mbox_peek_data,
+};
+
+static const struct mbox_chan_ops xilinx_mbox_poll_ops = {
+	.send_data = xilinx_mbox_poll_send_data,
+	.startup = xilinx_mbox_poll_startup,
+	.shutdown = xilinx_mbox_poll_shutdown,
+	.last_tx_done = xilinx_mbox_last_tx_done,
+	.peek_data = xilinx_mbox_peek_data,
+};
+
+static int xilinx_mbox_probe(struct platform_device *pdev)
+{
+	struct xilinx_mbox *mbox;
+	struct resource	*regs;
+	int ret;
+
+	mbox = devm_kzalloc(&pdev->dev, sizeof(*mbox), GFP_KERNEL);
+	if (!mbox)
+		return -ENOMEM;
+
+	/* get clk and enable */
+	mbox->clk = devm_clk_get(&pdev->dev, "mbox");
+	if (IS_ERR(mbox->clk)) {
+		dev_err(&pdev->dev, "Couldn't get clk.\n");
+		return PTR_ERR(mbox->clk);
+	}
+
+	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
+	mbox->mbox_base = devm_ioremap_resource(&pdev->dev, regs);
+	if (IS_ERR(mbox->mbox_base))
+		return PTR_ERR(mbox->mbox_base);
+
+	mbox->irq = platform_get_irq(pdev, 0);
+	/* if irq is present, we can use it, otherwise, poll */
+	if (mbox->irq > 0) {
+		mbox->controller.txdone_irq = true;
+		mbox->controller.ops = &xilinx_mbox_irq_ops;
+	} else {
+		dev_info(&pdev->dev, "IRQ not found, fallback to polling.\n");
+		mbox->controller.txdone_poll = true;
+		mbox->controller.txpoll_period = MBOX_POLLING_MS;
+		mbox->controller.ops = &xilinx_mbox_poll_ops;
+
+		setup_timer(&mbox->rxpoll_timer, xilinx_mbox_poll_rx,
+			    (unsigned long)&mbox->chan);
+	}
+
+	mbox->dev = &pdev->dev;
+
+	/* hardware supports only one channel. */
+	mbox->controller.dev = mbox->dev;
+	mbox->controller.num_chans = 1;
+	mbox->controller.chans = &mbox->chan;
+
+	ret = mbox_controller_register(&mbox->controller);
+	if (ret) {
+		dev_err(&pdev->dev, "Register mailbox failed\n");
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, mbox);
+
+	return 0;
+}
+
+static int xilinx_mbox_remove(struct platform_device *pdev)
+{
+	struct xilinx_mbox *mbox = platform_get_drvdata(pdev);
+
+	mbox_controller_unregister(&mbox->controller);
+
+	return 0;
+}
+
+static const struct of_device_id xilinx_mbox_match[] = {
+	{ .compatible = "xlnx,mailbox-2.1" },
+	{ /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, xilinx_mbox_match);
+
+static struct platform_driver xilinx_mbox_driver = {
+	.probe	= xilinx_mbox_probe,
+	.remove	= xilinx_mbox_remove,
+	.driver	= {
+		.name	= KBUILD_MODNAME,
+		.of_match_table	= xilinx_mbox_match,
+	},
+};
+
+module_platform_driver(xilinx_mbox_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Xilinx mailbox specific functions");
+MODULE_AUTHOR("Moritz Fischer <moritz.fischer@ettus.com>");
-- 
2.4.3

Re: [PATCHv6 1/2] dts: Adding docs for Xilinx LogiCORE IP mailbox driver.

[Sören Brinkmann]

On Mon, 2015-07-06 at 10:16AM -0700, Moritz Fischer wrote:
> Signed-off-by: Moritz Fischer <moritz.fischer@ettus.com>
> Acked-by: Michal Simek <michal.simek@xilinx.com>
> ---
>  .../devicetree/bindings/mailbox/xilinx-mailbox.txt | 44 ++++++++++++++++++++++
>  1 file changed, 44 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt
> 
> diff --git a/Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt b/Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt
> new file mode 100644
> index 0000000..97b81f8
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt
> @@ -0,0 +1,44 @@
> +Xilinx Mailbox Driver
> +=====================
> +
> +Required properties:
> +- compatible       : "xlnx,mailbox-2.1".
> +- reg              :  physical base address of the mailbox and length of
> +                      memory mapped region.
> +- #mbox-cells      :  common mailbox binding property to identify the number
> +                      of cells required for the mailbox specifier, should be 0
> +- clocks           :  phandle to clock provider
> +- clock-names      :  must be 'mbox'
> +
> +Optional properties:
> +- interrupt-parent : interrupt source phandle
> +- interrupts       : interrupt number, The interrupt specifier format
> +                     depends on the interrupt controller parent.
> +
> +Example:
> +	mbox: mailbox@40400000 {
> +		compatible = "xlnx,mailbox-2.1";
> +		reg = <0x40400000 0x100>;
> +		interrupt-parent = <&intc>;
> +		interrupts = <5>;
> +		#mbox-cells = <0>;
> +		clocks = <&clkc 15>;
> +		clock-names = "mbox";
> +	};
> +
> +Mailbox client
> +===============
> +"mboxes" and the optional "mbox-names" (please see
> +Documentation/devicetree/bindings/mailbox/mailbox.txt for details). Each value
> +of the mboxes property should contain a phandle to the mailbox controller
> +device node and second argument is the channel index. It must be 0 (hardware
> +support only one channel). The equivalent "mbox-names" property value can be
> +used to give a name to the communication channel to be used by the client user.
> +
> +Example:
> +	mclient0: mclient0@400 {
> +		compatible = "client-1.0";
> +		reg = <0x400 0x10>;
> +		mbox-names = "mbox";
> +		mboxes = <&mbox 0>;

Sorry, to bring this up again, but I'm confused regarding the #mbox-cells
thing. Above it says #mbox-cells is 0. In that case, shouldn't the
'mboxes' property not only be '<&mbox>'?

Moreover, the generic mailbox bindings
(https://www.kernel.org/doc/Documentation/devicetree/bindings/mailbox/mailbox.txt)
mandate #mbox-cells to be at least 1.

Does something need to be aligned here?

	Sören

[PATCHv6 1/2] dts: Adding docs for Xilinx LogiCORE IP mailbox driver.

[Sören Brinkmann]

On Mon, 2015-07-06 at 10:16AM -0700, Moritz Fischer wrote:
> Signed-off-by: Moritz Fischer <moritz.fischer@ettus.com>
> Acked-by: Michal Simek <michal.simek@xilinx.com>
> ---
>  .../devicetree/bindings/mailbox/xilinx-mailbox.txt | 44 ++++++++++++++++++++++
>  1 file changed, 44 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt
> 
> diff --git a/Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt b/Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt
> new file mode 100644
> index 0000000..97b81f8
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt
> @@ -0,0 +1,44 @@
> +Xilinx Mailbox Driver
> +=====================
> +
> +Required properties:
> +- compatible       : "xlnx,mailbox-2.1".
> +- reg              :  physical base address of the mailbox and length of
> +                      memory mapped region.
> +- #mbox-cells      :  common mailbox binding property to identify the number
> +                      of cells required for the mailbox specifier, should be 0
> +- clocks           :  phandle to clock provider
> +- clock-names      :  must be 'mbox'
> +
> +Optional properties:
> +- interrupt-parent : interrupt source phandle
> +- interrupts       : interrupt number, The interrupt specifier format
> +                     depends on the interrupt controller parent.
> +
> +Example:
> +	mbox: mailbox at 40400000 {
> +		compatible = "xlnx,mailbox-2.1";
> +		reg = <0x40400000 0x100>;
> +		interrupt-parent = <&intc>;
> +		interrupts = <5>;
> +		#mbox-cells = <0>;
> +		clocks = <&clkc 15>;
> +		clock-names = "mbox";
> +	};
> +
> +Mailbox client
> +===============
> +"mboxes" and the optional "mbox-names" (please see
> +Documentation/devicetree/bindings/mailbox/mailbox.txt for details). Each value
> +of the mboxes property should contain a phandle to the mailbox controller
> +device node and second argument is the channel index. It must be 0 (hardware
> +support only one channel). The equivalent "mbox-names" property value can be
> +used to give a name to the communication channel to be used by the client user.
> +
> +Example:
> +	mclient0: mclient0 at 400 {
> +		compatible = "client-1.0";
> +		reg = <0x400 0x10>;
> +		mbox-names = "mbox";
> +		mboxes = <&mbox 0>;

Sorry, to bring this up again, but I'm confused regarding the #mbox-cells
thing. Above it says #mbox-cells is 0. In that case, shouldn't the
'mboxes' property not only be '<&mbox>'?

Moreover, the generic mailbox bindings
(https://www.kernel.org/doc/Documentation/devicetree/bindings/mailbox/mailbox.txt)
mandate #mbox-cells to be at least 1.

Does something need to be aligned here?

	S?ren

Re: [PATCHv6 1/2] dts: Adding docs for Xilinx LogiCORE IP mailbox driver.

[Jassi Brar]

On Mon, Jul 6, 2015 at 10:57 PM, Sören Brinkmann
<soren.brinkmann@xilinx.com> wrote:
> On Mon, 2015-07-06 at 10:16AM -0700, Moritz Fischer wrote:
>> Signed-off-by: Moritz Fischer <moritz.fischer@ettus.com>
>> Acked-by: Michal Simek <michal.simek@xilinx.com>
>> ---
>>  .../devicetree/bindings/mailbox/xilinx-mailbox.txt | 44 ++++++++++++++++++++++
>>  1 file changed, 44 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt
>>
>> diff --git a/Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt b/Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt
>> new file mode 100644
>> index 0000000..97b81f8
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt
>> @@ -0,0 +1,44 @@
>> +Xilinx Mailbox Driver
>> +=====================
>> +
>> +Required properties:
>> +- compatible       : "xlnx,mailbox-2.1".
>> +- reg              :  physical base address of the mailbox and length of
>> +                      memory mapped region.
>> +- #mbox-cells      :  common mailbox binding property to identify the number
>> +                      of cells required for the mailbox specifier, should be 0
>> +- clocks           :  phandle to clock provider
>> +- clock-names      :  must be 'mbox'
>> +
>> +Optional properties:
>> +- interrupt-parent : interrupt source phandle
>> +- interrupts       : interrupt number, The interrupt specifier format
>> +                     depends on the interrupt controller parent.
>> +
>> +Example:
>> +     mbox: mailbox@40400000 {
>> +             compatible = "xlnx,mailbox-2.1";
>> +             reg = <0x40400000 0x100>;
>> +             interrupt-parent = <&intc>;
>> +             interrupts = <5>;
>> +             #mbox-cells = <0>;
>> +             clocks = <&clkc 15>;
>> +             clock-names = "mbox";
>> +     };
>> +
>> +Mailbox client
>> +===============
>> +"mboxes" and the optional "mbox-names" (please see
>> +Documentation/devicetree/bindings/mailbox/mailbox.txt for details). Each value
>> +of the mboxes property should contain a phandle to the mailbox controller
>> +device node and second argument is the channel index. It must be 0 (hardware
>> +support only one channel). The equivalent "mbox-names" property value can be
>> +used to give a name to the communication channel to be used by the client user.
>> +
>> +Example:
>> +     mclient0: mclient0@400 {
>> +             compatible = "client-1.0";
>> +             reg = <0x400 0x10>;
>> +             mbox-names = "mbox";
>> +             mboxes = <&mbox 0>;
>
> Sorry, to bring this up again, but I'm confused regarding the #mbox-cells
> thing. Above it says #mbox-cells is 0. In that case, shouldn't the
> 'mboxes' property not only be '<&mbox>'?
>
Yeah, this is inconsistent. Either provide your own of_xlate() for
#cells=0  or have #cells=1 to use stock of_xlate() and specify <&mbox
0> for the channel.

Re: [PATCHv6 1/2] dts: Adding docs for Xilinx LogiCORE IP mailbox driver.

[Jassi Brar]

On Mon, Jul 6, 2015 at 10:57 PM, Sören Brinkmann
<soren.brinkmann@xilinx.com> wrote:
> On Mon, 2015-07-06 at 10:16AM -0700, Moritz Fischer wrote:
>> Signed-off-by: Moritz Fischer <moritz.fischer@ettus.com>
>> Acked-by: Michal Simek <michal.simek@xilinx.com>
>> ---
>>  .../devicetree/bindings/mailbox/xilinx-mailbox.txt | 44 ++++++++++++++++++++++
>>  1 file changed, 44 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt
>>
>> diff --git a/Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt b/Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt
>> new file mode 100644
>> index 0000000..97b81f8
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt
>> @@ -0,0 +1,44 @@
>> +Xilinx Mailbox Driver
>> +=====================
>> +
>> +Required properties:
>> +- compatible       : "xlnx,mailbox-2.1".
>> +- reg              :  physical base address of the mailbox and length of
>> +                      memory mapped region.
>> +- #mbox-cells      :  common mailbox binding property to identify the number
>> +                      of cells required for the mailbox specifier, should be 0
>> +- clocks           :  phandle to clock provider
>> +- clock-names      :  must be 'mbox'
>> +
>> +Optional properties:
>> +- interrupt-parent : interrupt source phandle
>> +- interrupts       : interrupt number, The interrupt specifier format
>> +                     depends on the interrupt controller parent.
>> +
>> +Example:
>> +     mbox: mailbox@40400000 {
>> +             compatible = "xlnx,mailbox-2.1";
>> +             reg = <0x40400000 0x100>;
>> +             interrupt-parent = <&intc>;
>> +             interrupts = <5>;
>> +             #mbox-cells = <0>;
>> +             clocks = <&clkc 15>;
>> +             clock-names = "mbox";
>> +     };
>> +
>> +Mailbox client
>> +===============
>> +"mboxes" and the optional "mbox-names" (please see
>> +Documentation/devicetree/bindings/mailbox/mailbox.txt for details). Each value
>> +of the mboxes property should contain a phandle to the mailbox controller
>> +device node and second argument is the channel index. It must be 0 (hardware
>> +support only one channel). The equivalent "mbox-names" property value can be
>> +used to give a name to the communication channel to be used by the client user.
>> +
>> +Example:
>> +     mclient0: mclient0@400 {
>> +             compatible = "client-1.0";
>> +             reg = <0x400 0x10>;
>> +             mbox-names = "mbox";
>> +             mboxes = <&mbox 0>;
>
> Sorry, to bring this up again, but I'm confused regarding the #mbox-cells
> thing. Above it says #mbox-cells is 0. In that case, shouldn't the
> 'mboxes' property not only be '<&mbox>'?
>
Yeah, this is inconsistent. Either provide your own of_xlate() for
#cells=0  or have #cells=1 to use stock of_xlate() and specify <&mbox
0> for the channel.

[PATCHv6 1/2] dts: Adding docs for Xilinx LogiCORE IP mailbox driver.

[Jassi Brar]

On Mon, Jul 6, 2015 at 10:57 PM, S?ren Brinkmann
<soren.brinkmann@xilinx.com> wrote:
> On Mon, 2015-07-06 at 10:16AM -0700, Moritz Fischer wrote:
>> Signed-off-by: Moritz Fischer <moritz.fischer@ettus.com>
>> Acked-by: Michal Simek <michal.simek@xilinx.com>
>> ---
>>  .../devicetree/bindings/mailbox/xilinx-mailbox.txt | 44 ++++++++++++++++++++++
>>  1 file changed, 44 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt
>>
>> diff --git a/Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt b/Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt
>> new file mode 100644
>> index 0000000..97b81f8
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt
>> @@ -0,0 +1,44 @@
>> +Xilinx Mailbox Driver
>> +=====================
>> +
>> +Required properties:
>> +- compatible       : "xlnx,mailbox-2.1".
>> +- reg              :  physical base address of the mailbox and length of
>> +                      memory mapped region.
>> +- #mbox-cells      :  common mailbox binding property to identify the number
>> +                      of cells required for the mailbox specifier, should be 0
>> +- clocks           :  phandle to clock provider
>> +- clock-names      :  must be 'mbox'
>> +
>> +Optional properties:
>> +- interrupt-parent : interrupt source phandle
>> +- interrupts       : interrupt number, The interrupt specifier format
>> +                     depends on the interrupt controller parent.
>> +
>> +Example:
>> +     mbox: mailbox at 40400000 {
>> +             compatible = "xlnx,mailbox-2.1";
>> +             reg = <0x40400000 0x100>;
>> +             interrupt-parent = <&intc>;
>> +             interrupts = <5>;
>> +             #mbox-cells = <0>;
>> +             clocks = <&clkc 15>;
>> +             clock-names = "mbox";
>> +     };
>> +
>> +Mailbox client
>> +===============
>> +"mboxes" and the optional "mbox-names" (please see
>> +Documentation/devicetree/bindings/mailbox/mailbox.txt for details). Each value
>> +of the mboxes property should contain a phandle to the mailbox controller
>> +device node and second argument is the channel index. It must be 0 (hardware
>> +support only one channel). The equivalent "mbox-names" property value can be
>> +used to give a name to the communication channel to be used by the client user.
>> +
>> +Example:
>> +     mclient0: mclient0 at 400 {
>> +             compatible = "client-1.0";
>> +             reg = <0x400 0x10>;
>> +             mbox-names = "mbox";
>> +             mboxes = <&mbox 0>;
>
> Sorry, to bring this up again, but I'm confused regarding the #mbox-cells
> thing. Above it says #mbox-cells is 0. In that case, shouldn't the
> 'mboxes' property not only be '<&mbox>'?
>
Yeah, this is inconsistent. Either provide your own of_xlate() for
#cells=0  or have #cells=1 to use stock of_xlate() and specify <&mbox
0> for the channel.