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
Signed-off-by: Moritz Fischer <[email protected]>
Acked-by: Michal Simek <[email protected]>
---
.../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
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 <[email protected]>
Acked-by: Michal Simek <[email protected]>
---
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 <[email protected]>
S: Maintained
F: drivers/net/ethernet/xilinx/xilinx_axienet*
+XILINX MAILBOX DRIVER
+M: Moritz Fischer <[email protected]>
+L: [email protected]
+S: Maintained
+F: drivers/mailbox/mailbox-xilinx.c
+F: Documentation/devicetree/bindings/mailbox/xilinx-mailbox.txt
+
XILINX UARTLITE SERIAL DRIVER
M: Peter Korsgaard <[email protected]>
L: [email protected]
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 <[email protected]>");
--
2.4.3
On Mon, 2015-07-06 at 10:16AM -0700, Moritz Fischer wrote:
> Signed-off-by: Moritz Fischer <[email protected]>
> Acked-by: Michal Simek <[email protected]>
> ---
> .../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
On Mon, Jul 6, 2015 at 10:57 PM, Sören Brinkmann
<[email protected]> wrote:
> On Mon, 2015-07-06 at 10:16AM -0700, Moritz Fischer wrote:
>> Signed-off-by: Moritz Fischer <[email protected]>
>> Acked-by: Michal Simek <[email protected]>
>> ---
>> .../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.