[PATCH v6 0/2] Xilinx ZynqMP IPI Mailbox Controller Driver

[PATCH v6 0/2] Xilinx ZynqMP IPI Mailbox Controller Driver

[Wendy Liang]

Introduce mailbox controller driver for ZynqMP IPI(Inter-processor
interrupt) IP core.

As the device tree bindings have been updated. Do not have "Reviewed-by"
nor "Acked-by" in the dt-bindings commit.

v6:
 - dts-binding, remove compatible property from IPI subnode

v5:
 - fix check patch warning on write a paragraph to describe the kconfig
   symbol.

v4:
 - make IPI mailboxes as subnodes to the IPI agent device node to properly
   describe the hardware.

v3:
 - add NULL entry to of_device_id of IPI controller

v2:
 - change SPDX-License-Identifier license text style in .c file
 - replace xlnx-ipi-ids with xlnx,ipi-ids


Wendy Liang (2):
  mailbox: ZynqMP IPI mailbox controller
  dt-bindings: mailbox: Add Xilinx IPI Mailbox

 .../bindings/mailbox/xlnx,zynqmp-ipi-mailbox.txt   | 127 ++++
 drivers/mailbox/Kconfig                            |   9 +
 drivers/mailbox/Makefile                           |   2 +
 drivers/mailbox/zynqmp-ipi-mailbox.c               | 762 +++++++++++++++++++++
 include/linux/mailbox/zynqmp-ipi-message.h         |  24 +
 5 files changed, 924 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mailbox/xlnx,zynqmp-ipi-mailbox.txt
 create mode 100644 drivers/mailbox/zynqmp-ipi-mailbox.c
 create mode 100644 include/linux/mailbox/zynqmp-ipi-message.h

-- 
2.7.4

[PATCH v6 1/2] mailbox: ZynqMP IPI mailbox controller

[Wendy Liang]

This patch is to introduce ZynqMP IPI mailbox controller driver
to use the ZynqMP IPI block as mailboxes.

Signed-off-by: Wendy Liang <wendy.liang@xilinx.com>
---
 drivers/mailbox/Kconfig                    |   9 +
 drivers/mailbox/Makefile                   |   2 +
 drivers/mailbox/zynqmp-ipi-mailbox.c       | 762 +++++++++++++++++++++++++++++
 include/linux/mailbox/zynqmp-ipi-message.h |  24 +
 4 files changed, 797 insertions(+)
 create mode 100644 drivers/mailbox/zynqmp-ipi-mailbox.c
 create mode 100644 include/linux/mailbox/zynqmp-ipi-message.h

diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index 3eeb12e9..10bfe3f 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig
@@ -205,4 +205,13 @@ config MTK_CMDQ_MBOX
 	  mailbox driver. The CMDQ is used to help read/write registers with
 	  critical time limitation, such as updating display configuration
 	  during the vblank.
+
+config ZYNQMP_IPI_MBOX
+	tristate "Xilinx ZynqMP IPI Mailbox"
+	depends on ARCH_ZYNQMP && OF
+	help
+	  Mailbox implementation for Xilinx ZynqMP IPI controller. It is used
+	  to send notification or short message between processors on Xilinx
+	  UltraScale+ MPSoC platforms. Say Y here if you want to have this
+	  support.
 endif
diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
index c818b5d..bb3d604 100644
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile
@@ -44,3 +44,5 @@ obj-$(CONFIG_TEGRA_HSP_MBOX)	+= tegra-hsp.o
 obj-$(CONFIG_STM32_IPCC) 	+= stm32-ipcc.o
 
 obj-$(CONFIG_MTK_CMDQ_MBOX)	+= mtk-cmdq-mailbox.o
+
+obj-$(CONFIG_ZYNQMP_IPI_MBOX)  += zynqmp-ipi-mailbox.o
diff --git a/drivers/mailbox/zynqmp-ipi-mailbox.c b/drivers/mailbox/zynqmp-ipi-mailbox.c
new file mode 100644
index 0000000..bc02864
--- /dev/null
+++ b/drivers/mailbox/zynqmp-ipi-mailbox.c
@@ -0,0 +1,762 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Xilinx Inter Processor Interrupt(IPI) Mailbox Driver
+ *
+ * Copyright (C) 2018 Xilinx Inc.
+ *
+ */
+
+#include <linux/arm-smccc.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/mailbox_controller.h>
+#include <linux/mailbox/zynqmp-ipi-message.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+
+/* IPI agent ID any */
+#define IPI_ID_ANY 0xFFUL
+
+/* indicate if ZynqMP IPI mailbox driver uses SMC calls or HVC calls */
+#define USE_SMC 0
+#define USE_HVC 1
+
+/* Default IPI SMC function IDs */
+#define SMC_IPI_MAILBOX_OPEN            0x82001000U
+#define SMC_IPI_MAILBOX_RELEASE         0x82001001U
+#define SMC_IPI_MAILBOX_STATUS_ENQUIRY  0x82001002U
+#define SMC_IPI_MAILBOX_NOTIFY          0x82001003U
+#define SMC_IPI_MAILBOX_ACK             0x82001004U
+#define SMC_IPI_MAILBOX_ENABLE_IRQ      0x82001005U
+#define SMC_IPI_MAILBOX_DISABLE_IRQ     0x82001006U
+
+/* IPI SMC Macros */
+#define IPI_SMC_OPEN_IRQ_MASK		0x00000001UL /* IRQ enable bit in IPI
+						      * open SMC call
+						      */
+#define IPI_SMC_NOTIFY_BLOCK_MASK	0x00000001UL /* Flag to indicate if
+						      * IPI notification needs
+						      * to be blocking.
+						      */
+#define IPI_SMC_ENQUIRY_DIRQ_MASK       0x00000001UL /* Flag to indicate if
+						      * notification interrupt
+						      * to be disabled.
+						      */
+#define IPI_SMC_ACK_EIRQ_MASK           0x00000001UL /* Flag to indicate if
+						      * notification interrupt
+						      * to be enabled.
+						      */
+
+/* IPI mailbox status */
+#define IPI_MB_STATUS_IDLE              0
+#define IPI_MB_STATUS_SEND_PENDING      1
+#define IPI_MB_STATUS_RECV_PENDING      2
+
+#define IPI_MB_CHNL_TX 0 /* IPI mailbox TX channel */
+#define IPI_MB_CHNL_RX 1 /* IPI mailbox RX channel */
+
+/**
+ * struct zynqmp_ipi_mchan - Description of a Xilinx ZynqMP IPI mailbox channel
+ * @is_opened: indicate if the IPI channel is opened
+ * @req_buf: local to remote request buffer start address
+ * @resp_buf: local to remote response buffer start address
+ * @req_buf_size: request buffer size
+ * @resp_buf_size: response buffer size
+ * @rx_buf: receive buffer to pass received message to client
+ * @chan_type: channel type
+ */
+struct zynqmp_ipi_mchan {
+	int is_opened;
+	void __iomem *req_buf;
+	void __iomem *resp_buf;
+	void *rx_buf;
+	size_t req_buf_size;
+	size_t resp_buf_size;
+	unsigned int chan_type;
+};
+
+/**
+ * struct zynqmp_ipi_mbox - Description of a ZynqMP IPI mailbox
+ *                          platform data.
+ * @pdata:		  pointer to the IPI private data
+ * @dev:                  device pointer corresponding to the Xilinx ZynqMP
+ *                        IPI mailbox
+ * @remote_id:            remote IPI agent ID
+ * @mbox:                 mailbox Controller
+ * @mchans:               array for channels, tx channel and rx channel.
+ * @irq:                  IPI agent interrupt ID
+ */
+struct zynqmp_ipi_mbox {
+	struct zynqmp_ipi_pdata *pdata;
+	struct device dev;
+	u32 remote_id;
+	struct mbox_controller mbox;
+	struct zynqmp_ipi_mchan mchans[2];
+};
+
+/**
+ * struct zynqmp_ipi_pdata - Description of z ZynqMP IPI agent platform data.
+ *
+ * @dev:                  device pointer corresponding to the Xilinx ZynqMP
+ *                        IPI agent
+ * @irq:                  IPI agent interrupt ID
+ * @method:               IPI SMC or HVC is going to be used
+ * @local_id:             local IPI agent ID
+ * @ipi_mboxes:           IPI mailboxes of this IPI agent
+ */
+struct zynqmp_ipi_pdata {
+	struct device *dev;
+	int irq;
+	unsigned int method;
+	u32 local_id;
+	int num_mboxes;
+	struct zynqmp_ipi_mbox *ipi_mboxes;
+};
+
+static struct device_driver zynqmp_ipi_mbox_driver = {
+	.owner = THIS_MODULE,
+	.name = "zynqmp-ipi-mbox",
+};
+
+static void zynqmp_ipi_fw_call(struct zynqmp_ipi_mbox *ipi_mbox,
+			       unsigned long a0, unsigned long a3,
+			       unsigned long a4, unsigned long a5,
+			       unsigned long a6, unsigned long a7,
+			       struct arm_smccc_res *res)
+{
+	struct zynqmp_ipi_pdata *pdata = ipi_mbox->pdata;
+	unsigned long a1, a2;
+
+	a1 = pdata->local_id;
+	a2 = ipi_mbox->remote_id;
+	if (pdata->method == USE_SMC)
+		arm_smccc_smc(a0, a1, a2, a3, a4, a5, a6, a7, res);
+	else
+		arm_smccc_hvc(a0, a1, a2, a3, a4, a5, a6, a7, res);
+}
+
+/**
+ * zynqmp_ipi_interrupt - Interrupt handler for IPI notification
+ *
+ * @irq:  Interrupt number
+ * @data: ZynqMP IPI mailbox platform data.
+ *
+ * Return: -EINVAL if there is no instance
+ * IRQ_NONE if the interrupt is not ours.
+ * IRQ_HANDLED if the rx interrupt was successfully handled.
+ */
+static irqreturn_t zynqmp_ipi_interrupt(int irq, void *data)
+{
+	struct zynqmp_ipi_pdata *pdata = data;
+	struct mbox_chan *chan;
+	struct zynqmp_ipi_mbox *ipi_mbox;
+	struct zynqmp_ipi_mchan *mchan;
+	struct zynqmp_ipi_message *msg;
+	u64 arg0, arg3;
+	struct arm_smccc_res res;
+	int ret, i;
+
+	arg0 = SMC_IPI_MAILBOX_STATUS_ENQUIRY;
+	arg3 = IPI_SMC_ENQUIRY_DIRQ_MASK;
+	for (i = 0; i < pdata->num_mboxes; i++) {
+		ipi_mbox = &pdata->ipi_mboxes[i];
+		mchan = &ipi_mbox->mchans[IPI_MB_CHNL_RX];
+		chan = &ipi_mbox->mbox.chans[IPI_MB_CHNL_RX];
+		zynqmp_ipi_fw_call(ipi_mbox, arg0, arg3, 0, 0, 0, 0, &res);
+		ret = (int)(res.a0 & 0xFFFFFFFF);
+		if (ret > 0 && ret & IPI_MB_STATUS_RECV_PENDING) {
+			if (mchan->is_opened) {
+				msg = mchan->rx_buf;
+				msg->len = mchan->req_buf_size;
+				memcpy_fromio(msg->data, mchan->req_buf,
+					      msg->len);
+				mbox_chan_received_data(chan, (void *)msg);
+				return IRQ_HANDLED;
+			}
+		}
+	}
+	return IRQ_NONE;
+}
+
+/**
+ * zynqmp_ipi_peek_data - Peek to see if there are any rx messages.
+ *
+ * @chan: Channel Pointer
+ *
+ * Return: 'true' if there is pending rx data, 'false' if there is none.
+ */
+static bool zynqmp_ipi_peek_data(struct mbox_chan *chan)
+{
+	struct device *dev = chan->mbox->dev;
+	struct zynqmp_ipi_mbox *ipi_mbox = dev_get_drvdata(dev);
+	struct zynqmp_ipi_mchan *mchan = chan->con_priv;
+	int ret;
+	u64 arg0;
+	struct arm_smccc_res res;
+
+	if (WARN_ON(!ipi_mbox)) {
+		dev_err(dev, "no platform drv data??\n");
+		return false;
+	}
+
+	arg0 = SMC_IPI_MAILBOX_STATUS_ENQUIRY;
+	zynqmp_ipi_fw_call(ipi_mbox, arg0, 0, 0, 0, 0, 0, &res);
+	ret = (int)(res.a0 & 0xFFFFFFFF);
+
+	if (mchan->chan_type == IPI_MB_CHNL_TX) {
+		/* TX channel, check if the message has been acked
+		 * by the remote, if yes, response is available.
+		 */
+		if (ret < 0 || ret & IPI_MB_STATUS_SEND_PENDING)
+			return false;
+		else
+			return true;
+	} else if (ret > 0 && ret & IPI_MB_STATUS_RECV_PENDING) {
+		/* RX channel, check if there is message arrived. */
+		return true;
+	}
+	return false;
+}
+
+/**
+ * zynqmp_ipi_last_tx_done - See if the last tx message is sent
+ *
+ * @chan: Channel pointer
+ *
+ * Return: 'true' is no pending tx data, 'false' if there are any.
+ */
+static bool zynqmp_ipi_last_tx_done(struct mbox_chan *chan)
+{
+	struct device *dev = chan->mbox->dev;
+	struct zynqmp_ipi_mbox *ipi_mbox = dev_get_drvdata(dev);
+	struct zynqmp_ipi_mchan *mchan = chan->con_priv;
+	int ret;
+	u64 arg0;
+	struct arm_smccc_res res;
+	struct zynqmp_ipi_message *msg;
+
+	if (WARN_ON(!ipi_mbox)) {
+		dev_err(dev, "no platform drv data??\n");
+		return false;
+	}
+
+	if (mchan->chan_type == IPI_MB_CHNL_TX) {
+		/* We only need to check if the message been taken
+		 * by the remote in the TX channel
+		 */
+		arg0 = SMC_IPI_MAILBOX_STATUS_ENQUIRY;
+		zynqmp_ipi_fw_call(ipi_mbox, arg0, 0, 0, 0, 0, 0, &res);
+		/* Check the SMC call status, a0 of the result */
+		ret = (int)(res.a0 & 0xFFFFFFFF);
+		if (ret < 0 || ret & IPI_MB_STATUS_SEND_PENDING)
+			return false;
+
+		msg = mchan->rx_buf;
+		msg->len = mchan->resp_buf_size;
+		memcpy_fromio(msg->data, mchan->resp_buf, msg->len);
+		mbox_chan_received_data(chan, (void *)msg);
+		return true;
+	}
+	/* Always true for the response message in RX channel */
+	return true;
+}
+
+/**
+ * zynqmp_ipi_send_data - Send data
+ *
+ * @chan: Channel Pointer
+ * @data: Message Pointer
+ *
+ * Return: 0 if all goes good, else appropriate error messages.
+ */
+static int zynqmp_ipi_send_data(struct mbox_chan *chan, void *data)
+{
+	struct device *dev = chan->mbox->dev;
+	struct zynqmp_ipi_mbox *ipi_mbox = dev_get_drvdata(dev);
+	struct zynqmp_ipi_mchan *mchan = chan->con_priv;
+	struct zynqmp_ipi_message *msg = data;
+	u64 arg0;
+	struct arm_smccc_res res;
+	u32 timeout;
+	int ret;
+
+	if (WARN_ON(!ipi_mbox)) {
+		dev_err(dev, "no platform drv data??\n");
+		return -EINVAL;
+	}
+
+	if (mchan->chan_type == IPI_MB_CHNL_TX) {
+		/* Send request message */
+		if (msg && msg->len > mchan->req_buf_size) {
+			dev_err(dev, "channel %d message length %u > max %lu\n",
+				mchan->chan_type, (unsigned int)msg->len,
+				mchan->req_buf_size);
+			return -EINVAL;
+		}
+		/* Enquire if the mailbox is free to send message */
+		arg0 = SMC_IPI_MAILBOX_STATUS_ENQUIRY;
+		timeout = 10;
+		if (msg && msg->len) {
+			timeout = 10;
+			do {
+				zynqmp_ipi_fw_call(ipi_mbox, arg0,
+						   0, 0, 0, 0, 0, &res);
+				ret = res.a0 & 0xFFFFFFFF;
+				if (ret >= 0 &&
+				    !(ret & IPI_MB_STATUS_SEND_PENDING))
+					break;
+				usleep_range(1, 2);
+				timeout--;
+			} while (timeout);
+			if (!timeout) {
+				dev_warn(dev, "chan %d sending msg timeout.\n",
+					 ipi_mbox->remote_id);
+				return -ETIME;
+			}
+			memcpy_toio(mchan->req_buf, msg->data, msg->len);
+		}
+		/* Kick IPI mailbox to send message */
+		arg0 = SMC_IPI_MAILBOX_NOTIFY;
+		zynqmp_ipi_fw_call(ipi_mbox, arg0, 0, 0, 0, 0, 0, &res);
+	} else {
+		/* Send response message */
+		if (msg && msg->len > mchan->resp_buf_size) {
+			dev_err(dev, "channel %d message length %u > max %lu\n",
+				mchan->chan_type, (unsigned int)msg->len,
+				mchan->resp_buf_size);
+			return -EINVAL;
+		}
+		if (msg && msg->len)
+			memcpy(mchan->resp_buf, msg->data, msg->len);
+		arg0 = SMC_IPI_MAILBOX_NOTIFY;
+		arg0 = SMC_IPI_MAILBOX_ACK;
+		zynqmp_ipi_fw_call(ipi_mbox, arg0, IPI_SMC_ACK_EIRQ_MASK,
+				   0, 0, 0, 0, &res);
+	}
+	return 0;
+}
+
+/**
+ * zynqmp_ipi_startup - Startup the IPI channel
+ *
+ * @chan: Channel pointer
+ *
+ * Return: 0 if all goes good, else return corresponding error message
+ */
+static int zynqmp_ipi_startup(struct mbox_chan *chan)
+{
+	struct device *dev = chan->mbox->dev;
+	struct zynqmp_ipi_mbox *ipi_mbox = dev_get_drvdata(dev);
+	struct zynqmp_ipi_mchan *mchan = chan->con_priv;
+	u64 arg0;
+	struct arm_smccc_res res;
+	int ret = 0;
+	unsigned int nchan_type;
+
+	if (mchan->is_opened)
+		return 0;
+
+	/* If no channel has been opened, open the IPI mailbox */
+	nchan_type = (mchan->chan_type + 1) % 2;
+	if (!ipi_mbox->mchans[nchan_type].is_opened) {
+		arg0 = SMC_IPI_MAILBOX_OPEN;
+		zynqmp_ipi_fw_call(ipi_mbox, arg0, 0, 0, 0, 0, 0, &res);
+		/* Check the SMC call status, a0 of the result */
+		ret = (int)(res.a0 | 0xFFFFFFFF);
+		if (res.a0 < 0) {
+			dev_err(dev, "SMC to open the IPI channel failed.\n");
+			ret = res.a0;
+			return ret;
+		}
+		ret = 0;
+	}
+
+	/* If it is RX channel, enable the IPI notification interrupt */
+	if (mchan->chan_type == IPI_MB_CHNL_RX) {
+		arg0 = SMC_IPI_MAILBOX_ENABLE_IRQ;
+		zynqmp_ipi_fw_call(ipi_mbox, arg0, 0, 0, 0, 0, 0, &res);
+	}
+	mchan->is_opened = 1;
+
+	return ret;
+}
+
+/**
+ * zynqmp_ipi_shutdown - Shutdown the IPI channel
+ *
+ * @chan: Channel pointer
+ */
+static void zynqmp_ipi_shutdown(struct mbox_chan *chan)
+{
+	struct device *dev = chan->mbox->dev;
+	struct zynqmp_ipi_mbox *ipi_mbox = dev_get_drvdata(dev);
+	struct zynqmp_ipi_mchan *mchan = chan->con_priv;
+	u64 arg0;
+	struct arm_smccc_res res;
+	unsigned int chan_type;
+
+	if (!mchan->is_opened)
+		return;
+
+	/* If it is RX channel, disable notification interrupt */
+	chan_type = mchan->chan_type;
+	if (chan_type == IPI_MB_CHNL_RX) {
+		arg0 = SMC_IPI_MAILBOX_DISABLE_IRQ;
+		zynqmp_ipi_fw_call(ipi_mbox, arg0, 0, 0, 0, 0, 0, &res);
+	}
+	/* Release IPI mailbox if no other channel is opened */
+	chan_type = (chan_type + 1) % 2;
+	if (!ipi_mbox->mchans[chan_type].is_opened) {
+		arg0 = SMC_IPI_MAILBOX_RELEASE;
+		zynqmp_ipi_fw_call(ipi_mbox, arg0, 0, 0, 0, 0, 0, &res);
+	}
+
+	mchan->is_opened = 0;
+}
+
+/* ZynqMP IPI mailbox operations */
+static const struct mbox_chan_ops zynqmp_ipi_chan_ops = {
+	.startup = zynqmp_ipi_startup,
+	.shutdown = zynqmp_ipi_shutdown,
+	.peek_data = zynqmp_ipi_peek_data,
+	.last_tx_done = zynqmp_ipi_last_tx_done,
+	.send_data = zynqmp_ipi_send_data,
+};
+
+/**
+ * zynqmp_ipi_of_xlate - Translate of phandle to IPI mailbox channel
+ *
+ * @mbox: mailbox controller pointer
+ * @p:    phandle pointer
+ *
+ * Return: Mailbox channel, else return error pointer.
+ */
+static struct mbox_chan *zynqmp_ipi_of_xlate(struct mbox_controller *mbox,
+					     const struct of_phandle_args *p)
+{
+	struct mbox_chan *chan;
+	struct device *dev = mbox->dev;
+	unsigned int chan_type;
+
+	/* Only supports TX and RX channels */
+	chan_type = p->args[0];
+	if (chan_type != IPI_MB_CHNL_TX && chan_type != IPI_MB_CHNL_RX) {
+		dev_err(dev, "req chnl failure: invalid chnl type %u.\n",
+			chan_type);
+		return ERR_PTR(-EINVAL);
+	}
+	chan = &mbox->chans[chan_type];
+	return chan;
+}
+
+static const struct of_device_id zynqmp_ipi_of_match[] = {
+	{.compatible = "xlnx,zynqmp-ipi-mailbox"},
+};
+MODULE_DEVICE_TABLE(of, zynqmp_ipi_of_match);
+
+/**
+ * zynqmp_ipi_mbox_get_buf_res - Get buffer resource from the IPI dev node
+ *
+ * @node: IPI mbox device child node
+ * @name: name of the IPI buffer
+ * @res: pointer to where the resource information will be stored.
+ *
+ * Return: 0 for success, negative value for failure
+ */
+static int zynqmp_ipi_mbox_get_buf_res(struct device_node *node,
+				       const char *name,
+				       struct resource *res)
+{
+	int ret, index;
+
+	index = of_property_match_string(node, "reg-names", name);
+	if (index >= 0) {
+		ret = of_address_to_resource(node, index, res);
+		if (ret < 0)
+			return -EINVAL;
+		return 0;
+	}
+	return -ENODEV;
+}
+
+/**
+ * zynqmp_ipi_mbox_dev_release() - release the existence of a ipi mbox dev
+ *
+ * This is to avoid the no device release() function kernel warning.
+ *
+ * @dev: the ipi mailbox device
+ */
+static void zynqmp_ipi_mbox_dev_release(struct device *dev)
+{
+	(void)dev;
+}
+
+/**
+ * zynqmp_ipi_mbox_probe - probe IPI mailbox resource from device node
+ *
+ * @ipi_mbox: pointer to IPI mailbox private data structure
+ * @node: IPI mailbox device node
+ *
+ * Return: 0 for success, negative value for failure
+ */
+static int zynqmp_ipi_mbox_probe(struct zynqmp_ipi_mbox *ipi_mbox,
+				 struct device_node *node)
+{
+	struct zynqmp_ipi_mchan *mchan;
+	struct mbox_chan *chans;
+	struct mbox_controller *mbox;
+	struct resource res;
+	struct device *dev, *mdev;
+	const char *name;
+	int ret;
+
+	dev = ipi_mbox->pdata->dev;
+	/* Initialize dev for IPI mailbox */
+	ipi_mbox->dev.parent = dev;
+	ipi_mbox->dev.release = NULL;
+	ipi_mbox->dev.of_node = node;
+	dev_set_name(&ipi_mbox->dev, "%s", of_node_full_name(node));
+	dev_set_drvdata(&ipi_mbox->dev, ipi_mbox);
+	ipi_mbox->dev.release = zynqmp_ipi_mbox_dev_release;
+	ipi_mbox->dev.driver = &zynqmp_ipi_mbox_driver;
+	ret = device_register(&ipi_mbox->dev);
+	if (ret) {
+		dev_err(dev, "Failed to register ipi mbox dev.\n");
+		return ret;
+	}
+	mdev = &ipi_mbox->dev;
+
+	mchan = &ipi_mbox->mchans[IPI_MB_CHNL_TX];
+	name = "local_request_region";
+	ret = zynqmp_ipi_mbox_get_buf_res(node, name, &res);
+	if (!ret) {
+		mchan->req_buf_size = resource_size(&res);
+		mchan->req_buf = devm_ioremap(mdev, res.start,
+					      mchan->req_buf_size);
+		if (IS_ERR(mchan->req_buf)) {
+			dev_err(mdev, "Unable to map IPI buffer I/O memory\n");
+			ret = PTR_ERR(mchan->req_buf);
+			return ret;
+		}
+	} else if (ret != -ENODEV) {
+		dev_err(mdev, "Unmatched resource %s, %d.\n", name, ret);
+		return ret;
+	}
+
+	name = "remote_response_region";
+	ret = zynqmp_ipi_mbox_get_buf_res(node, name, &res);
+	if (!ret) {
+		mchan->resp_buf_size = resource_size(&res);
+		mchan->resp_buf = devm_ioremap(mdev, res.start,
+					       mchan->resp_buf_size);
+		if (IS_ERR(mchan->resp_buf)) {
+			dev_err(mdev, "Unable to map IPI buffer I/O memory\n");
+			ret = PTR_ERR(mchan->resp_buf);
+			return ret;
+		}
+	} else if (ret != -ENODEV) {
+		dev_err(mdev, "Unmatched resource %s.\n", name);
+		return ret;
+	}
+	mchan->rx_buf = devm_kzalloc(mdev,
+				     mchan->resp_buf_size +
+				     sizeof(struct zynqmp_ipi_message),
+				     GFP_KERNEL);
+	if (!mchan->rx_buf)
+		return -ENOMEM;
+
+	mchan = &ipi_mbox->mchans[IPI_MB_CHNL_RX];
+	name = "remote_request_region";
+	ret = zynqmp_ipi_mbox_get_buf_res(node, name, &res);
+	if (!ret) {
+		mchan->req_buf_size = resource_size(&res);
+		mchan->req_buf = devm_ioremap(mdev, res.start,
+					      mchan->req_buf_size);
+		if (IS_ERR(mchan->req_buf)) {
+			dev_err(mdev, "Unable to map IPI buffer I/O memory\n");
+			ret = PTR_ERR(mchan->req_buf);
+			return ret;
+		}
+	} else if (ret != -ENODEV) {
+		dev_err(mdev, "Unmatched resource %s.\n", name);
+		return ret;
+	}
+
+	name = "local_response_region";
+	ret = zynqmp_ipi_mbox_get_buf_res(node, name, &res);
+	if (!ret) {
+		mchan->resp_buf_size = resource_size(&res);
+		mchan->resp_buf = devm_ioremap(mdev, res.start,
+					       mchan->resp_buf_size);
+		if (IS_ERR(mchan->resp_buf)) {
+			dev_err(mdev, "Unable to map IPI buffer I/O memory\n");
+			ret = PTR_ERR(mchan->resp_buf);
+			return ret;
+		}
+	} else if (ret != -ENODEV) {
+		dev_err(mdev, "Unmatched resource %s.\n", name);
+		return ret;
+	}
+	mchan->rx_buf = devm_kzalloc(mdev,
+				     mchan->resp_buf_size +
+				     sizeof(struct zynqmp_ipi_message),
+				     GFP_KERNEL);
+	if (!mchan->rx_buf)
+		return -ENOMEM;
+
+	/* Get the IPI remote agent ID */
+	ret = of_property_read_u32(node, "xlnx,ipi-id", &ipi_mbox->remote_id);
+	if (ret < 0) {
+		dev_err(dev, "No IPI remote ID is specified.\n");
+		return ret;
+	}
+
+	mbox = &ipi_mbox->mbox;
+	mbox->dev = mdev;
+	mbox->ops = &zynqmp_ipi_chan_ops;
+	mbox->num_chans = 2;
+	mbox->txdone_irq = false;
+	mbox->txdone_poll = true;
+	mbox->txpoll_period = 5;
+	mbox->of_xlate = zynqmp_ipi_of_xlate;
+	chans = devm_kzalloc(mdev, 2 * sizeof(*chans), GFP_KERNEL);
+	if (!chans)
+		return -ENOMEM;
+	mbox->chans = chans;
+	chans[IPI_MB_CHNL_TX].con_priv = &ipi_mbox->mchans[IPI_MB_CHNL_TX];
+	chans[IPI_MB_CHNL_RX].con_priv = &ipi_mbox->mchans[IPI_MB_CHNL_RX];
+	ipi_mbox->mchans[IPI_MB_CHNL_TX].chan_type = IPI_MB_CHNL_TX;
+	ipi_mbox->mchans[IPI_MB_CHNL_RX].chan_type = IPI_MB_CHNL_RX;
+	ret = mbox_controller_register(mbox);
+	if (ret)
+		dev_err(mdev,
+			"Failed to register mbox_controller(%d)\n", ret);
+	else
+		dev_info(mdev, "Probed ZynqMP IPI Mailbox driver.\n");
+	return ret;
+}
+
+/**
+ * zynqmp_ipi_free_mboxes - Free IPI mailboxes devices
+ *
+ * @pdata: IPI private data
+ */
+static void zynqmp_ipi_free_mboxes(struct zynqmp_ipi_pdata *pdata)
+{
+	struct zynqmp_ipi_mbox *ipi_mbox;
+	int i;
+
+	i = pdata->num_mboxes;
+	for (; i >= 0; i--) {
+		ipi_mbox = &pdata->ipi_mboxes[i];
+		if (ipi_mbox->dev.parent) {
+			mbox_controller_unregister(&ipi_mbox->mbox);
+			device_unregister(&ipi_mbox->dev);
+		}
+	}
+}
+
+static int zynqmp_ipi_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *nc, *np = pdev->dev.of_node;
+	struct zynqmp_ipi_pdata *pdata;
+	struct zynqmp_ipi_mbox *mbox;
+	int i, ret = -EINVAL;
+
+	i = 0;
+	for_each_available_child_of_node(np, nc)
+		i++;
+	pdata = devm_kzalloc(dev, sizeof(*pdata) + (i * sizeof(*mbox)),
+			     GFP_KERNEL);
+	if (!pdata)
+		return -ENOMEM;
+	pdata->dev = dev;
+
+	/* Get the IPI local agents ID */
+	ret = of_property_read_u32(np, "xlnx,ipi-id", &pdata->local_id);
+	if (ret < 0) {
+		dev_err(dev, "No IPI local ID is specified.\n");
+		return ret;
+	}
+
+	pdata->num_mboxes = i;
+	pdata->ipi_mboxes = (struct zynqmp_ipi_mbox *)
+			    ((char *)pdata + sizeof(*pdata));
+
+	mbox = pdata->ipi_mboxes;
+	for_each_available_child_of_node(np, nc) {
+		mbox->pdata = pdata;
+		ret = zynqmp_ipi_mbox_probe(mbox, nc);
+		if (ret) {
+			dev_err(dev, "failed to probe subdev.\n");
+			ret = -EINVAL;
+			goto free_mbox_dev;
+		}
+		mbox++;
+	}
+
+	/* IPI IRQ */
+	ret = platform_get_irq(pdev, 0);
+	if (ret < 0) {
+		dev_err(dev, "unable to find IPI IRQ.\n");
+		goto free_mbox_dev;
+	}
+	pdata->irq = ret;
+	ret = devm_request_irq(dev, pdata->irq, zynqmp_ipi_interrupt,
+			       IRQF_SHARED, dev_name(dev), pdata);
+	if (ret) {
+		dev_err(dev, "IRQ %d is not requested successfully.\n",
+			pdata->irq);
+		goto free_mbox_dev;
+	}
+
+	platform_set_drvdata(pdev, pdata);
+	return ret;
+
+free_mbox_dev:
+	zynqmp_ipi_free_mboxes(pdata);
+	return ret;
+}
+
+static int zynqmp_ipi_remove(struct platform_device *pdev)
+{
+	struct zynqmp_ipi_pdata *pdata;
+
+	pdata = platform_get_drvdata(pdev);
+	zynqmp_ipi_free_mboxes(pdata);
+
+	return 0;
+}
+
+static struct platform_driver zynqmp_ipi_driver = {
+	.probe = zynqmp_ipi_probe,
+	.remove = zynqmp_ipi_remove,
+	.driver = {
+		   .name = "zynqmp-ipi",
+		   .of_match_table = of_match_ptr(zynqmp_ipi_of_match),
+	},
+};
+
+static int __init zynqmp_ipi_init(void)
+{
+	return platform_driver_register(&zynqmp_ipi_driver);
+}
+subsys_initcall(zynqmp_ipi_init);
+
+static void __exit zynqmp_ipi_exit(void)
+{
+	platform_driver_unregister(&zynqmp_ipi_driver);
+}
+module_exit(zynqmp_ipi_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Xilinx ZynqMP IPI Mailbox driver");
+MODULE_AUTHOR("Xilinx Inc.");
diff --git a/include/linux/mailbox/zynqmp-ipi-message.h b/include/linux/mailbox/zynqmp-ipi-message.h
new file mode 100644
index 0000000..72a9d9d
--- /dev/null
+++ b/include/linux/mailbox/zynqmp-ipi-message.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ *  Copyright (C) 2017 Xilinx Inc.
+ *
+ */
+
+#ifndef _LINUX_ZYNQMP_IPI_MESSAGE_H_
+#define _LINUX_ZYNQMP_IPI_MESSAGE_H_
+
+/**
+ * struct zynqmp_ipi_message - ZynqMP IPI message structure
+ * @len:  Length of the request message
+ * @data: Request message
+ *
+ * This is the structure for data used in mbox_send_message
+ * the maximum length of data buffer is fixed to 12 bytes.
+ * Client is supposed to be aware of this.
+ */
+struct zynqmp_ipi_message {
+	size_t len;
+	u8 data[0];
+};
+
+#endif /* _LINUX_ZYNQMP_IPI_MESSAGE_H_ */
-- 
2.7.4

[PATCH v6 2/2] dt-bindings: mailbox: Add Xilinx IPI Mailbox

[Wendy Liang]

Xilinx ZynqMP IPI(Inter Processor Interrupt) is a hardware block
in ZynqMP SoC used for the communication between various processor
systems.

Signed-off-by: Wendy Liang <wendy.liang@xilinx.com>
---
 .../bindings/mailbox/xlnx,zynqmp-ipi-mailbox.txt   | 127 +++++++++++++++++++++
 1 file changed, 127 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mailbox/xlnx,zynqmp-ipi-mailbox.txt

diff --git a/Documentation/devicetree/bindings/mailbox/xlnx,zynqmp-ipi-mailbox.txt b/Documentation/devicetree/bindings/mailbox/xlnx,zynqmp-ipi-mailbox.txt
new file mode 100644
index 0000000..4438432
--- /dev/null
+++ b/Documentation/devicetree/bindings/mailbox/xlnx,zynqmp-ipi-mailbox.txt
@@ -0,0 +1,127 @@
+Xilinx IPI Mailbox Controller
+========================================
+
+The Xilinx IPI(Inter Processor Interrupt) mailbox controller is to manage
+messaging between two Xilinx Zynq UltraScale+ MPSoC IPI agents. Each IPI
+agent owns registers used for notification and buffers for message.
+
+               +-------------------------------------+
+               | Xilinx ZynqMP IPI Controller        |
+               +-------------------------------------+
+    +--------------------------------------------------+
+ATF                    |                     |
+                       |                     |
+                       |                     |
+    +--------------------------+             |
+                       |                     |
+                       |                     |
+    +--------------------------------------------------+
+            +------------------------------------------+
+            |  +----------------+   +----------------+ |
+Hardware    |  |  IPI Agent     |   |  IPI Buffers   | |
+            |  |  Registers     |   |                | |
+            |  |                |   |                | |
+            |  +----------------+   +----------------+ |
+            |                                          |
+            | Xilinx IPI Agent Block                   |
+            +------------------------------------------+
+
+
+Controller Device Node:
+===========================
+Required properties:
+--------------------
+IPI agent node:
+- compatible:		Shall be: "xlnx,zynqmp-ipi-mailbox"
+- interrupt-parent:	Phandle for the interrupt controller
+- interrupts:		Interrupt information corresponding to the
+			interrupt-names property.
+- xlnx,ipi-id:		local Xilinx IPI agent ID
+- #address-cells:	number of address cells of internal IPI mailbox nodes
+- #size-cells:		number of size cells of internal IPI mailbox nodes
+
+Internal IPI mailbox node:
+- reg:			IPI buffers address ranges
+- reg-names:		Names of the reg resources. It should have:
+			* local_request_region
+			  - IPI request msg buffer written by local and read
+			    by remote
+			* local_response_region
+			  - IPI response msg buffer written by local and read
+			    by remote
+			* remote_request_region
+			  - IPI request msg buffer written by remote and read
+			    by local
+			* remote_response_region
+			  - IPI response msg buffer written by remote and read
+			    by local
+- #mbox-cells:		Shall be 1. It contains:
+			* tx(0) or rx(1) channel
+- xlnx,ipi-id:		remote Xilinx IPI agent ID of which the mailbox is
+			connected to.
+
+Optional properties:
+--------------------
+- method:              The method of accessing the IPI agent registers.
+                       Permitted values are: "smc" and "hvc". Default is
+                       "smc".
+
+Client Device Node:
+===========================
+Required properties:
+--------------------
+- mboxes:		Standard property to specify a mailbox
+			(See ./mailbox.txt)
+- mbox-names:		List of identifier  strings for each mailbox
+			channel.
+
+Example:
+===========================
+	zynqmp_ipi {
+		compatible = "xlnx,zynqmp-ipi-mailbox";
+		interrupt-parent = <&gic>;
+		interrupts = <0 29 4>;
+		xlnx,ipi-id = <0>;
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ranges;
+
+		/* APU<->RPU0 IPI mailbox controller */
+		ipi_mailbox_rpu0: mailbox@ff90400 {
+			reg = <0xff990400 0x20>,
+			      <0xff990420 0x20>,
+			      <0xff990080 0x20>,
+			      <0xff9900a0 0x20>;
+			reg-names = "local_request_region",
+				    "local_response_region",
+				    "remote_request_region",
+				    "remote_response_region";
+			#mbox-cells = <1>;
+			xlnx,ipi-id = <1>;
+		};
+		/* APU<->RPU1 IPI mailbox controller */
+		ipi_mailbox_rpu1: mailbox@ff990440 {
+			reg = <0xff990440 0x20>,
+			      <0xff990460 0x20>,
+			      <0xff990280 0x20>,
+			      <0xff9902a0 0x20>;
+			reg-names = "local_request_region",
+				    "local_response_region",
+				    "remote_request_region",
+				    "remote_response_region";
+			#mbox-cells = <1>;
+			xlnx,ipi-id = <2>;
+		};
+	};
+	rpu0 {
+		...
+		mboxes = <&ipi_mailbox_rpu0 0>,
+			 <&ipi_mailbox_rpu0 1>;
+		mbox-names = "tx", "rx";
+	};
+	rpu1 {
+		...
+		mboxes = <&ipi_mailbox_rpu1 0>,
+			 <&ipi_mailbox_rpu1 1>;
+		mbox-names = "tx", "rx";
+	};
-- 
2.7.4

Re: [PATCH v6 2/2] dt-bindings: mailbox: Add Xilinx IPI Mailbox

[Rob Herring]

On Mon, 19 Nov 2018 13:26:01 -0800, Wendy Liang wrote:
> Xilinx ZynqMP IPI(Inter Processor Interrupt) is a hardware block
> in ZynqMP SoC used for the communication between various processor
> systems.
> 
> Signed-off-by: Wendy Liang <wendy.liang@xilinx.com>
> ---
>  .../bindings/mailbox/xlnx,zynqmp-ipi-mailbox.txt   | 127 +++++++++++++++++++++
>  1 file changed, 127 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mailbox/xlnx,zynqmp-ipi-mailbox.txt
> 

Reviewed-by: Rob Herring <robh@kernel.org>

RE: [PATCH v6 1/2] mailbox: ZynqMP IPI mailbox controller

[Jiaying Liang]

> -----Original Message-----
> From: Wendy Liang [mailto:wendy.liang@xilinx.com]
> Sent: Monday, November 19, 2018 1:26 PM
> To: jassisinghbrar@gmail.com; Michal Simek <michals@xilinx.com>;
> robh+dt@kernel.org; mark.rutland@arm.com
> Cc: linux-kernel@vger.kernel.org; linux-arm-kernel@lists.infradead.org;
> devicetree@vger.kernel.org; Jiaying Liang <jliang@xilinx.com>
> Subject: [PATCH v6 1/2] mailbox: ZynqMP IPI mailbox controller
> 
> This patch is to introduce ZynqMP IPI mailbox controller driver to use the
> ZynqMP IPI block as mailboxes.
> 
> Signed-off-by: Wendy Liang <wendy.liang@xilinx.com>
> ---
>  drivers/mailbox/Kconfig                    |   9 +
>  drivers/mailbox/Makefile                   |   2 +
>  drivers/mailbox/zynqmp-ipi-mailbox.c       | 762
> +++++++++++++++++++++++++++++
>  include/linux/mailbox/zynqmp-ipi-message.h |  24 +
>  4 files changed, 797 insertions(+)
>  create mode 100644 drivers/mailbox/zynqmp-ipi-mailbox.c
>  create mode 100644 include/linux/mailbox/zynqmp-ipi-message.h
> 
> diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig index
> 3eeb12e9..10bfe3f 100644
> --- a/drivers/mailbox/Kconfig
> +++ b/drivers/mailbox/Kconfig
> @@ -205,4 +205,13 @@ config MTK_CMDQ_MBOX
>  	  mailbox driver. The CMDQ is used to help read/write registers with
>  	  critical time limitation, such as updating display configuration
>  	  during the vblank.
> +
> +config ZYNQMP_IPI_MBOX
> +	tristate "Xilinx ZynqMP IPI Mailbox"
> +	depends on ARCH_ZYNQMP && OF
> +	help
> +	  Mailbox implementation for Xilinx ZynqMP IPI controller. It is used
> +	  to send notification or short message between processors on Xilinx
> +	  UltraScale+ MPSoC platforms. Say Y here if you want to have this
> +	  support.
>  endif
> diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile index
> c818b5d..bb3d604 100644
> --- a/drivers/mailbox/Makefile
> +++ b/drivers/mailbox/Makefile
> @@ -44,3 +44,5 @@ obj-$(CONFIG_TEGRA_HSP_MBOX)	+= tegra-
> hsp.o
>  obj-$(CONFIG_STM32_IPCC) 	+= stm32-ipcc.o
> 
>  obj-$(CONFIG_MTK_CMDQ_MBOX)	+= mtk-cmdq-mailbox.o
> +
> +obj-$(CONFIG_ZYNQMP_IPI_MBOX)  += zynqmp-ipi-mailbox.o
> diff --git a/drivers/mailbox/zynqmp-ipi-mailbox.c b/drivers/mailbox/zynqmp-
> ipi-mailbox.c
> new file mode 100644
> index 0000000..bc02864
> --- /dev/null
> +++ b/drivers/mailbox/zynqmp-ipi-mailbox.c
> @@ -0,0 +1,762 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Xilinx Inter Processor Interrupt(IPI) Mailbox Driver
> + *
> + * Copyright (C) 2018 Xilinx Inc.
> + *
> + */
> +
> +#include <linux/arm-smccc.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/mailbox_controller.h>
> +#include <linux/mailbox/zynqmp-ipi-message.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/of_device.h>
> +#include <linux/of_irq.h>
> +#include <linux/platform_device.h>
> +
> +/* IPI agent ID any */
> +#define IPI_ID_ANY 0xFFUL
> +
> +/* indicate if ZynqMP IPI mailbox driver uses SMC calls or HVC calls */
> +#define USE_SMC 0 #define USE_HVC 1
> +
> +/* Default IPI SMC function IDs */
> +#define SMC_IPI_MAILBOX_OPEN            0x82001000U
> +#define SMC_IPI_MAILBOX_RELEASE         0x82001001U
> +#define SMC_IPI_MAILBOX_STATUS_ENQUIRY  0x82001002U
> +#define SMC_IPI_MAILBOX_NOTIFY          0x82001003U
> +#define SMC_IPI_MAILBOX_ACK             0x82001004U
> +#define SMC_IPI_MAILBOX_ENABLE_IRQ      0x82001005U
> +#define SMC_IPI_MAILBOX_DISABLE_IRQ     0x82001006U
> +
> +/* IPI SMC Macros */
> +#define IPI_SMC_OPEN_IRQ_MASK		0x00000001UL /* IRQ enable
> bit in IPI
> +						      * open SMC call
> +						      */
> +#define IPI_SMC_NOTIFY_BLOCK_MASK	0x00000001UL /* Flag to
> indicate if
> +						      * IPI notification needs
> +						      * to be blocking.
> +						      */
> +#define IPI_SMC_ENQUIRY_DIRQ_MASK       0x00000001UL /* Flag to
> indicate if
> +						      * notification interrupt
> +						      * to be disabled.
> +						      */
> +#define IPI_SMC_ACK_EIRQ_MASK           0x00000001UL /* Flag to indicate if
> +						      * notification interrupt
> +						      * to be enabled.
> +						      */
> +
> +/* IPI mailbox status */
> +#define IPI_MB_STATUS_IDLE              0
> +#define IPI_MB_STATUS_SEND_PENDING      1
> +#define IPI_MB_STATUS_RECV_PENDING      2
> +
> +#define IPI_MB_CHNL_TX 0 /* IPI mailbox TX channel */ #define
> +IPI_MB_CHNL_RX 1 /* IPI mailbox RX channel */
> +
> +/**
> + * struct zynqmp_ipi_mchan - Description of a Xilinx ZynqMP IPI mailbox
> +channel
> + * @is_opened: indicate if the IPI channel is opened
> + * @req_buf: local to remote request buffer start address
> + * @resp_buf: local to remote response buffer start address
> + * @req_buf_size: request buffer size
> + * @resp_buf_size: response buffer size
> + * @rx_buf: receive buffer to pass received message to client
> + * @chan_type: channel type
> + */
> +struct zynqmp_ipi_mchan {
> +	int is_opened;
> +	void __iomem *req_buf;
> +	void __iomem *resp_buf;
> +	void *rx_buf;
> +	size_t req_buf_size;
> +	size_t resp_buf_size;
> +	unsigned int chan_type;
> +};
> +
> +/**
> + * struct zynqmp_ipi_mbox - Description of a ZynqMP IPI mailbox
> + *                          platform data.
> + * @pdata:		  pointer to the IPI private data
> + * @dev:                  device pointer corresponding to the Xilinx ZynqMP
> + *                        IPI mailbox
> + * @remote_id:            remote IPI agent ID
> + * @mbox:                 mailbox Controller
> + * @mchans:               array for channels, tx channel and rx channel.
> + * @irq:                  IPI agent interrupt ID
> + */
> +struct zynqmp_ipi_mbox {
> +	struct zynqmp_ipi_pdata *pdata;
> +	struct device dev;
> +	u32 remote_id;
> +	struct mbox_controller mbox;
> +	struct zynqmp_ipi_mchan mchans[2];
> +};
> +
> +/**
> + * struct zynqmp_ipi_pdata - Description of z ZynqMP IPI agent platform
> data.
> + *
> + * @dev:                  device pointer corresponding to the Xilinx ZynqMP
> + *                        IPI agent
> + * @irq:                  IPI agent interrupt ID
> + * @method:               IPI SMC or HVC is going to be used
> + * @local_id:             local IPI agent ID
> + * @ipi_mboxes:           IPI mailboxes of this IPI agent
> + */
> +struct zynqmp_ipi_pdata {
> +	struct device *dev;
> +	int irq;
> +	unsigned int method;
> +	u32 local_id;
> +	int num_mboxes;
> +	struct zynqmp_ipi_mbox *ipi_mboxes;
> +};
> +
> +static struct device_driver zynqmp_ipi_mbox_driver = {
> +	.owner = THIS_MODULE,
> +	.name = "zynqmp-ipi-mbox",
> +};
> +
> +static void zynqmp_ipi_fw_call(struct zynqmp_ipi_mbox *ipi_mbox,
> +			       unsigned long a0, unsigned long a3,
> +			       unsigned long a4, unsigned long a5,
> +			       unsigned long a6, unsigned long a7,
> +			       struct arm_smccc_res *res)
> +{
> +	struct zynqmp_ipi_pdata *pdata = ipi_mbox->pdata;
> +	unsigned long a1, a2;
> +
> +	a1 = pdata->local_id;
> +	a2 = ipi_mbox->remote_id;
> +	if (pdata->method == USE_SMC)
> +		arm_smccc_smc(a0, a1, a2, a3, a4, a5, a6, a7, res);
> +	else
> +		arm_smccc_hvc(a0, a1, a2, a3, a4, a5, a6, a7, res); }
> +
> +/**
> + * zynqmp_ipi_interrupt - Interrupt handler for IPI notification
> + *
> + * @irq:  Interrupt number
> + * @data: ZynqMP IPI mailbox platform data.
> + *
> + * Return: -EINVAL if there is no instance
> + * IRQ_NONE if the interrupt is not ours.
> + * IRQ_HANDLED if the rx interrupt was successfully handled.
> + */
> +static irqreturn_t zynqmp_ipi_interrupt(int irq, void *data) {
> +	struct zynqmp_ipi_pdata *pdata = data;
> +	struct mbox_chan *chan;
> +	struct zynqmp_ipi_mbox *ipi_mbox;
> +	struct zynqmp_ipi_mchan *mchan;
> +	struct zynqmp_ipi_message *msg;
> +	u64 arg0, arg3;
> +	struct arm_smccc_res res;
> +	int ret, i;
> +
> +	arg0 = SMC_IPI_MAILBOX_STATUS_ENQUIRY;
> +	arg3 = IPI_SMC_ENQUIRY_DIRQ_MASK;
> +	for (i = 0; i < pdata->num_mboxes; i++) {
> +		ipi_mbox = &pdata->ipi_mboxes[i];
> +		mchan = &ipi_mbox->mchans[IPI_MB_CHNL_RX];
> +		chan = &ipi_mbox->mbox.chans[IPI_MB_CHNL_RX];
> +		zynqmp_ipi_fw_call(ipi_mbox, arg0, arg3, 0, 0, 0, 0, &res);
> +		ret = (int)(res.a0 & 0xFFFFFFFF);
> +		if (ret > 0 && ret & IPI_MB_STATUS_RECV_PENDING) {
> +			if (mchan->is_opened) {
> +				msg = mchan->rx_buf;
> +				msg->len = mchan->req_buf_size;
> +				memcpy_fromio(msg->data, mchan->req_buf,
> +					      msg->len);
> +				mbox_chan_received_data(chan, (void
> *)msg);
> +				return IRQ_HANDLED;
> +			}
> +		}
> +	}
> +	return IRQ_NONE;
> +}
> +
> +/**
> + * zynqmp_ipi_peek_data - Peek to see if there are any rx messages.
> + *
> + * @chan: Channel Pointer
> + *
> + * Return: 'true' if there is pending rx data, 'false' if there is none.
> + */
> +static bool zynqmp_ipi_peek_data(struct mbox_chan *chan) {
> +	struct device *dev = chan->mbox->dev;
> +	struct zynqmp_ipi_mbox *ipi_mbox = dev_get_drvdata(dev);
> +	struct zynqmp_ipi_mchan *mchan = chan->con_priv;
> +	int ret;
> +	u64 arg0;
> +	struct arm_smccc_res res;
> +
> +	if (WARN_ON(!ipi_mbox)) {
> +		dev_err(dev, "no platform drv data??\n");
> +		return false;
> +	}
> +
> +	arg0 = SMC_IPI_MAILBOX_STATUS_ENQUIRY;
> +	zynqmp_ipi_fw_call(ipi_mbox, arg0, 0, 0, 0, 0, 0, &res);
> +	ret = (int)(res.a0 & 0xFFFFFFFF);
> +
> +	if (mchan->chan_type == IPI_MB_CHNL_TX) {
> +		/* TX channel, check if the message has been acked
> +		 * by the remote, if yes, response is available.
> +		 */
> +		if (ret < 0 || ret & IPI_MB_STATUS_SEND_PENDING)
> +			return false;
> +		else
> +			return true;
> +	} else if (ret > 0 && ret & IPI_MB_STATUS_RECV_PENDING) {
> +		/* RX channel, check if there is message arrived. */
> +		return true;
> +	}
> +	return false;
> +}
> +
> +/**
> + * zynqmp_ipi_last_tx_done - See if the last tx message is sent
> + *
> + * @chan: Channel pointer
> + *
> + * Return: 'true' is no pending tx data, 'false' if there are any.
> + */
> +static bool zynqmp_ipi_last_tx_done(struct mbox_chan *chan) {
> +	struct device *dev = chan->mbox->dev;
> +	struct zynqmp_ipi_mbox *ipi_mbox = dev_get_drvdata(dev);
> +	struct zynqmp_ipi_mchan *mchan = chan->con_priv;
> +	int ret;
> +	u64 arg0;
> +	struct arm_smccc_res res;
> +	struct zynqmp_ipi_message *msg;
> +
> +	if (WARN_ON(!ipi_mbox)) {
> +		dev_err(dev, "no platform drv data??\n");
> +		return false;
> +	}
> +
> +	if (mchan->chan_type == IPI_MB_CHNL_TX) {
> +		/* We only need to check if the message been taken
> +		 * by the remote in the TX channel
> +		 */
> +		arg0 = SMC_IPI_MAILBOX_STATUS_ENQUIRY;
> +		zynqmp_ipi_fw_call(ipi_mbox, arg0, 0, 0, 0, 0, 0, &res);
> +		/* Check the SMC call status, a0 of the result */
> +		ret = (int)(res.a0 & 0xFFFFFFFF);
> +		if (ret < 0 || ret & IPI_MB_STATUS_SEND_PENDING)
> +			return false;
> +
> +		msg = mchan->rx_buf;
> +		msg->len = mchan->resp_buf_size;
> +		memcpy_fromio(msg->data, mchan->resp_buf, msg->len);
> +		mbox_chan_received_data(chan, (void *)msg);
> +		return true;
> +	}
> +	/* Always true for the response message in RX channel */
> +	return true;
> +}
> +
> +/**
> + * zynqmp_ipi_send_data - Send data
> + *
> + * @chan: Channel Pointer
> + * @data: Message Pointer
> + *
> + * Return: 0 if all goes good, else appropriate error messages.
> + */
> +static int zynqmp_ipi_send_data(struct mbox_chan *chan, void *data) {
> +	struct device *dev = chan->mbox->dev;
> +	struct zynqmp_ipi_mbox *ipi_mbox = dev_get_drvdata(dev);
> +	struct zynqmp_ipi_mchan *mchan = chan->con_priv;
> +	struct zynqmp_ipi_message *msg = data;
> +	u64 arg0;
> +	struct arm_smccc_res res;
> +	u32 timeout;
> +	int ret;
> +
> +	if (WARN_ON(!ipi_mbox)) {
> +		dev_err(dev, "no platform drv data??\n");
> +		return -EINVAL;
> +	}
> +
> +	if (mchan->chan_type == IPI_MB_CHNL_TX) {
> +		/* Send request message */
> +		if (msg && msg->len > mchan->req_buf_size) {
> +			dev_err(dev, "channel %d message length %u >
> max %lu\n",
> +				mchan->chan_type, (unsigned int)msg->len,
> +				mchan->req_buf_size);
> +			return -EINVAL;
> +		}
> +		/* Enquire if the mailbox is free to send message */
> +		arg0 = SMC_IPI_MAILBOX_STATUS_ENQUIRY;
> +		timeout = 10;
> +		if (msg && msg->len) {
> +			timeout = 10;
> +			do {
> +				zynqmp_ipi_fw_call(ipi_mbox, arg0,
> +						   0, 0, 0, 0, 0, &res);
> +				ret = res.a0 & 0xFFFFFFFF;
> +				if (ret >= 0 &&
> +				    !(ret & IPI_MB_STATUS_SEND_PENDING))
> +					break;
> +				usleep_range(1, 2);
> +				timeout--;
> +			} while (timeout);
> +			if (!timeout) {
> +				dev_warn(dev, "chan %d sending msg
> timeout.\n",
> +					 ipi_mbox->remote_id);
> +				return -ETIME;
> +			}
> +			memcpy_toio(mchan->req_buf, msg->data, msg->len);
> +		}
> +		/* Kick IPI mailbox to send message */
> +		arg0 = SMC_IPI_MAILBOX_NOTIFY;
> +		zynqmp_ipi_fw_call(ipi_mbox, arg0, 0, 0, 0, 0, 0, &res);
> +	} else {
> +		/* Send response message */
> +		if (msg && msg->len > mchan->resp_buf_size) {
> +			dev_err(dev, "channel %d message length %u >
> max %lu\n",
> +				mchan->chan_type, (unsigned int)msg->len,
> +				mchan->resp_buf_size);
> +			return -EINVAL;
> +		}
> +		if (msg && msg->len)
> +			memcpy(mchan->resp_buf, msg->data, msg->len);
> +		arg0 = SMC_IPI_MAILBOX_NOTIFY;
> +		arg0 = SMC_IPI_MAILBOX_ACK;
> +		zynqmp_ipi_fw_call(ipi_mbox, arg0,
> IPI_SMC_ACK_EIRQ_MASK,
> +				   0, 0, 0, 0, &res);
> +	}
> +	return 0;
> +}
> +
> +/**
> + * zynqmp_ipi_startup - Startup the IPI channel
> + *
> + * @chan: Channel pointer
> + *
> + * Return: 0 if all goes good, else return corresponding error message
> +*/ static int zynqmp_ipi_startup(struct mbox_chan *chan) {
> +	struct device *dev = chan->mbox->dev;
> +	struct zynqmp_ipi_mbox *ipi_mbox = dev_get_drvdata(dev);
> +	struct zynqmp_ipi_mchan *mchan = chan->con_priv;
> +	u64 arg0;
> +	struct arm_smccc_res res;
> +	int ret = 0;
> +	unsigned int nchan_type;
> +
> +	if (mchan->is_opened)
> +		return 0;
> +
> +	/* If no channel has been opened, open the IPI mailbox */
> +	nchan_type = (mchan->chan_type + 1) % 2;
> +	if (!ipi_mbox->mchans[nchan_type].is_opened) {
> +		arg0 = SMC_IPI_MAILBOX_OPEN;
> +		zynqmp_ipi_fw_call(ipi_mbox, arg0, 0, 0, 0, 0, 0, &res);
> +		/* Check the SMC call status, a0 of the result */
> +		ret = (int)(res.a0 | 0xFFFFFFFF);
> +		if (res.a0 < 0) {
> +			dev_err(dev, "SMC to open the IPI channel failed.\n");
> +			ret = res.a0;
> +			return ret;
> +		}
> +		ret = 0;
> +	}
> +
> +	/* If it is RX channel, enable the IPI notification interrupt */
> +	if (mchan->chan_type == IPI_MB_CHNL_RX) {
> +		arg0 = SMC_IPI_MAILBOX_ENABLE_IRQ;
> +		zynqmp_ipi_fw_call(ipi_mbox, arg0, 0, 0, 0, 0, 0, &res);
> +	}
> +	mchan->is_opened = 1;
> +
> +	return ret;
> +}
> +
> +/**
> + * zynqmp_ipi_shutdown - Shutdown the IPI channel
> + *
> + * @chan: Channel pointer
> + */
> +static void zynqmp_ipi_shutdown(struct mbox_chan *chan) {
> +	struct device *dev = chan->mbox->dev;
> +	struct zynqmp_ipi_mbox *ipi_mbox = dev_get_drvdata(dev);
> +	struct zynqmp_ipi_mchan *mchan = chan->con_priv;
> +	u64 arg0;
> +	struct arm_smccc_res res;
> +	unsigned int chan_type;
> +
> +	if (!mchan->is_opened)
> +		return;
> +
> +	/* If it is RX channel, disable notification interrupt */
> +	chan_type = mchan->chan_type;
> +	if (chan_type == IPI_MB_CHNL_RX) {
> +		arg0 = SMC_IPI_MAILBOX_DISABLE_IRQ;
> +		zynqmp_ipi_fw_call(ipi_mbox, arg0, 0, 0, 0, 0, 0, &res);
> +	}
> +	/* Release IPI mailbox if no other channel is opened */
> +	chan_type = (chan_type + 1) % 2;
> +	if (!ipi_mbox->mchans[chan_type].is_opened) {
> +		arg0 = SMC_IPI_MAILBOX_RELEASE;
> +		zynqmp_ipi_fw_call(ipi_mbox, arg0, 0, 0, 0, 0, 0, &res);
> +	}
> +
> +	mchan->is_opened = 0;
> +}
> +
> +/* ZynqMP IPI mailbox operations */
> +static const struct mbox_chan_ops zynqmp_ipi_chan_ops = {
> +	.startup = zynqmp_ipi_startup,
> +	.shutdown = zynqmp_ipi_shutdown,
> +	.peek_data = zynqmp_ipi_peek_data,
> +	.last_tx_done = zynqmp_ipi_last_tx_done,
> +	.send_data = zynqmp_ipi_send_data,
> +};
> +
> +/**
> + * zynqmp_ipi_of_xlate - Translate of phandle to IPI mailbox channel
> + *
> + * @mbox: mailbox controller pointer
> + * @p:    phandle pointer
> + *
> + * Return: Mailbox channel, else return error pointer.
> + */
> +static struct mbox_chan *zynqmp_ipi_of_xlate(struct mbox_controller
> *mbox,
> +					     const struct of_phandle_args *p) {
> +	struct mbox_chan *chan;
> +	struct device *dev = mbox->dev;
> +	unsigned int chan_type;
> +
> +	/* Only supports TX and RX channels */
> +	chan_type = p->args[0];
> +	if (chan_type != IPI_MB_CHNL_TX && chan_type != IPI_MB_CHNL_RX)
> {
> +		dev_err(dev, "req chnl failure: invalid chnl type %u.\n",
> +			chan_type);
> +		return ERR_PTR(-EINVAL);
> +	}
> +	chan = &mbox->chans[chan_type];
> +	return chan;
> +}
> +
> +static const struct of_device_id zynqmp_ipi_of_match[] = {
> +	{.compatible = "xlnx,zynqmp-ipi-mailbox"}, };
[Wendy] should add missing sentinel to the end of of_device_id table

> MODULE_DEVICE_TABLE(of,
> +zynqmp_ipi_of_match);
> +
> +/**
> + * zynqmp_ipi_mbox_get_buf_res - Get buffer resource from the IPI dev
> +node
> + *
> + * @node: IPI mbox device child node
> + * @name: name of the IPI buffer
> + * @res: pointer to where the resource information will be stored.
> + *
> + * Return: 0 for success, negative value for failure  */ static int
> +zynqmp_ipi_mbox_get_buf_res(struct device_node *node,
> +				       const char *name,
> +				       struct resource *res)
> +{
> +	int ret, index;
> +
> +	index = of_property_match_string(node, "reg-names", name);
> +	if (index >= 0) {
> +		ret = of_address_to_resource(node, index, res);
> +		if (ret < 0)
> +			return -EINVAL;
> +		return 0;
> +	}
> +	return -ENODEV;
> +}
> +
> +/**
> + * zynqmp_ipi_mbox_dev_release() - release the existence of a ipi mbox
> +dev
> + *
> + * This is to avoid the no device release() function kernel warning.
> + *
> + * @dev: the ipi mailbox device
> + */
> +static void zynqmp_ipi_mbox_dev_release(struct device *dev) {
> +	(void)dev;
> +}
> +
> +/**
> + * zynqmp_ipi_mbox_probe - probe IPI mailbox resource from device node
> + *
> + * @ipi_mbox: pointer to IPI mailbox private data structure
> + * @node: IPI mailbox device node
> + *
> + * Return: 0 for success, negative value for failure  */ static int
> +zynqmp_ipi_mbox_probe(struct zynqmp_ipi_mbox *ipi_mbox,
> +				 struct device_node *node)
> +{
> +	struct zynqmp_ipi_mchan *mchan;
> +	struct mbox_chan *chans;
> +	struct mbox_controller *mbox;
> +	struct resource res;
> +	struct device *dev, *mdev;
> +	const char *name;
> +	int ret;
> +
> +	dev = ipi_mbox->pdata->dev;
> +	/* Initialize dev for IPI mailbox */
> +	ipi_mbox->dev.parent = dev;
> +	ipi_mbox->dev.release = NULL;
> +	ipi_mbox->dev.of_node = node;
> +	dev_set_name(&ipi_mbox->dev, "%s", of_node_full_name(node));
> +	dev_set_drvdata(&ipi_mbox->dev, ipi_mbox);
> +	ipi_mbox->dev.release = zynqmp_ipi_mbox_dev_release;
> +	ipi_mbox->dev.driver = &zynqmp_ipi_mbox_driver;
> +	ret = device_register(&ipi_mbox->dev);
> +	if (ret) {
> +		dev_err(dev, "Failed to register ipi mbox dev.\n");
> +		return ret;
> +	}
> +	mdev = &ipi_mbox->dev;
> +
> +	mchan = &ipi_mbox->mchans[IPI_MB_CHNL_TX];
> +	name = "local_request_region";
> +	ret = zynqmp_ipi_mbox_get_buf_res(node, name, &res);
> +	if (!ret) {
> +		mchan->req_buf_size = resource_size(&res);
> +		mchan->req_buf = devm_ioremap(mdev, res.start,
> +					      mchan->req_buf_size);
> +		if (IS_ERR(mchan->req_buf)) {
> +			dev_err(mdev, "Unable to map IPI buffer I/O
> memory\n");
> +			ret = PTR_ERR(mchan->req_buf);
> +			return ret;
> +		}
> +	} else if (ret != -ENODEV) {
> +		dev_err(mdev, "Unmatched resource %s, %d.\n", name, ret);
> +		return ret;
> +	}
> +
> +	name = "remote_response_region";
> +	ret = zynqmp_ipi_mbox_get_buf_res(node, name, &res);
> +	if (!ret) {
> +		mchan->resp_buf_size = resource_size(&res);
> +		mchan->resp_buf = devm_ioremap(mdev, res.start,
> +					       mchan->resp_buf_size);
> +		if (IS_ERR(mchan->resp_buf)) {
> +			dev_err(mdev, "Unable to map IPI buffer I/O
> memory\n");
> +			ret = PTR_ERR(mchan->resp_buf);
> +			return ret;
> +		}
> +	} else if (ret != -ENODEV) {
> +		dev_err(mdev, "Unmatched resource %s.\n", name);
> +		return ret;
> +	}
> +	mchan->rx_buf = devm_kzalloc(mdev,
> +				     mchan->resp_buf_size +
> +				     sizeof(struct zynqmp_ipi_message),
> +				     GFP_KERNEL);
> +	if (!mchan->rx_buf)
> +		return -ENOMEM;
> +
> +	mchan = &ipi_mbox->mchans[IPI_MB_CHNL_RX];
> +	name = "remote_request_region";
> +	ret = zynqmp_ipi_mbox_get_buf_res(node, name, &res);
> +	if (!ret) {
> +		mchan->req_buf_size = resource_size(&res);
> +		mchan->req_buf = devm_ioremap(mdev, res.start,
> +					      mchan->req_buf_size);
> +		if (IS_ERR(mchan->req_buf)) {
> +			dev_err(mdev, "Unable to map IPI buffer I/O
> memory\n");
> +			ret = PTR_ERR(mchan->req_buf);
> +			return ret;
> +		}
> +	} else if (ret != -ENODEV) {
> +		dev_err(mdev, "Unmatched resource %s.\n", name);
> +		return ret;
> +	}
> +
> +	name = "local_response_region";
> +	ret = zynqmp_ipi_mbox_get_buf_res(node, name, &res);
> +	if (!ret) {
> +		mchan->resp_buf_size = resource_size(&res);
> +		mchan->resp_buf = devm_ioremap(mdev, res.start,
> +					       mchan->resp_buf_size);
> +		if (IS_ERR(mchan->resp_buf)) {
> +			dev_err(mdev, "Unable to map IPI buffer I/O
> memory\n");
> +			ret = PTR_ERR(mchan->resp_buf);
> +			return ret;
> +		}
> +	} else if (ret != -ENODEV) {
> +		dev_err(mdev, "Unmatched resource %s.\n", name);
> +		return ret;
> +	}
> +	mchan->rx_buf = devm_kzalloc(mdev,
> +				     mchan->resp_buf_size +
> +				     sizeof(struct zynqmp_ipi_message),
> +				     GFP_KERNEL);
> +	if (!mchan->rx_buf)
> +		return -ENOMEM;
> +
> +	/* Get the IPI remote agent ID */
> +	ret = of_property_read_u32(node, "xlnx,ipi-id", &ipi_mbox-
> >remote_id);
> +	if (ret < 0) {
> +		dev_err(dev, "No IPI remote ID is specified.\n");
> +		return ret;
> +	}
> +
> +	mbox = &ipi_mbox->mbox;
> +	mbox->dev = mdev;
> +	mbox->ops = &zynqmp_ipi_chan_ops;
> +	mbox->num_chans = 2;
> +	mbox->txdone_irq = false;
> +	mbox->txdone_poll = true;
> +	mbox->txpoll_period = 5;
> +	mbox->of_xlate = zynqmp_ipi_of_xlate;
> +	chans = devm_kzalloc(mdev, 2 * sizeof(*chans), GFP_KERNEL);
> +	if (!chans)
> +		return -ENOMEM;
> +	mbox->chans = chans;
> +	chans[IPI_MB_CHNL_TX].con_priv = &ipi_mbox-
> >mchans[IPI_MB_CHNL_TX];
> +	chans[IPI_MB_CHNL_RX].con_priv = &ipi_mbox-
> >mchans[IPI_MB_CHNL_RX];
> +	ipi_mbox->mchans[IPI_MB_CHNL_TX].chan_type = IPI_MB_CHNL_TX;
> +	ipi_mbox->mchans[IPI_MB_CHNL_RX].chan_type = IPI_MB_CHNL_RX;
> +	ret = mbox_controller_register(mbox);
> +	if (ret)
> +		dev_err(mdev,
> +			"Failed to register mbox_controller(%d)\n", ret);
> +	else
> +		dev_info(mdev, "Probed ZynqMP IPI Mailbox driver.\n");
> +	return ret;
> +}
> +
> +/**
> + * zynqmp_ipi_free_mboxes - Free IPI mailboxes devices
> + *
> + * @pdata: IPI private data
> + */
> +static void zynqmp_ipi_free_mboxes(struct zynqmp_ipi_pdata *pdata) {
> +	struct zynqmp_ipi_mbox *ipi_mbox;
> +	int i;
> +
> +	i = pdata->num_mboxes;
> +	for (; i >= 0; i--) {
> +		ipi_mbox = &pdata->ipi_mboxes[i];
> +		if (ipi_mbox->dev.parent) {
> +			mbox_controller_unregister(&ipi_mbox->mbox);
> +			device_unregister(&ipi_mbox->dev);
> +		}
> +	}
> +}
> +
> +static int zynqmp_ipi_probe(struct platform_device *pdev) {
> +	struct device *dev = &pdev->dev;
> +	struct device_node *nc, *np = pdev->dev.of_node;
> +	struct zynqmp_ipi_pdata *pdata;
> +	struct zynqmp_ipi_mbox *mbox;
> +	int i, ret = -EINVAL;
> +
> +	i = 0;
> +	for_each_available_child_of_node(np, nc)
> +		i++;
> +	pdata = devm_kzalloc(dev, sizeof(*pdata) + (i * sizeof(*mbox)),
> +			     GFP_KERNEL);
> +	if (!pdata)
> +		return -ENOMEM;
> +	pdata->dev = dev;
> +
> +	/* Get the IPI local agents ID */
> +	ret = of_property_read_u32(np, "xlnx,ipi-id", &pdata->local_id);
> +	if (ret < 0) {
> +		dev_err(dev, "No IPI local ID is specified.\n");
> +		return ret;
> +	}
> +
> +	pdata->num_mboxes = i;
> +	pdata->ipi_mboxes = (struct zynqmp_ipi_mbox *)
> +			    ((char *)pdata + sizeof(*pdata));
> +
> +	mbox = pdata->ipi_mboxes;
> +	for_each_available_child_of_node(np, nc) {
> +		mbox->pdata = pdata;
> +		ret = zynqmp_ipi_mbox_probe(mbox, nc);
> +		if (ret) {
> +			dev_err(dev, "failed to probe subdev.\n");
> +			ret = -EINVAL;
> +			goto free_mbox_dev;
> +		}
> +		mbox++;
> +	}
> +
> +	/* IPI IRQ */
> +	ret = platform_get_irq(pdev, 0);
> +	if (ret < 0) {
> +		dev_err(dev, "unable to find IPI IRQ.\n");
> +		goto free_mbox_dev;
> +	}
> +	pdata->irq = ret;
> +	ret = devm_request_irq(dev, pdata->irq, zynqmp_ipi_interrupt,
> +			       IRQF_SHARED, dev_name(dev), pdata);
> +	if (ret) {
> +		dev_err(dev, "IRQ %d is not requested successfully.\n",
> +			pdata->irq);
> +		goto free_mbox_dev;
> +	}
> +
> +	platform_set_drvdata(pdev, pdata);
> +	return ret;
> +
> +free_mbox_dev:
> +	zynqmp_ipi_free_mboxes(pdata);
> +	return ret;
> +}
> +
> +static int zynqmp_ipi_remove(struct platform_device *pdev) {
> +	struct zynqmp_ipi_pdata *pdata;
> +
> +	pdata = platform_get_drvdata(pdev);
> +	zynqmp_ipi_free_mboxes(pdata);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver zynqmp_ipi_driver = {
> +	.probe = zynqmp_ipi_probe,
> +	.remove = zynqmp_ipi_remove,
> +	.driver = {
> +		   .name = "zynqmp-ipi",
> +		   .of_match_table = of_match_ptr(zynqmp_ipi_of_match),
> +	},
> +};
> +
> +static int __init zynqmp_ipi_init(void) {
> +	return platform_driver_register(&zynqmp_ipi_driver);
> +}
> +subsys_initcall(zynqmp_ipi_init);
> +
> +static void __exit zynqmp_ipi_exit(void) {
> +	platform_driver_unregister(&zynqmp_ipi_driver);
> +}
> +module_exit(zynqmp_ipi_exit);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("Xilinx ZynqMP IPI Mailbox driver");
> +MODULE_AUTHOR("Xilinx Inc.");
> diff --git a/include/linux/mailbox/zynqmp-ipi-message.h
> b/include/linux/mailbox/zynqmp-ipi-message.h
> new file mode 100644
> index 0000000..72a9d9d
> --- /dev/null
> +++ b/include/linux/mailbox/zynqmp-ipi-message.h
> @@ -0,0 +1,24 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + *  Copyright (C) 2017 Xilinx Inc.
> + *
> + */
> +
> +#ifndef _LINUX_ZYNQMP_IPI_MESSAGE_H_
> +#define _LINUX_ZYNQMP_IPI_MESSAGE_H_
> +
> +/**
> + * struct zynqmp_ipi_message - ZynqMP IPI message structure
> + * @len:  Length of the request message
> + * @data: Request message
> + *
> + * This is the structure for data used in mbox_send_message
> + * the maximum length of data buffer is fixed to 12 bytes.
> + * Client is supposed to be aware of this.
> + */
> +struct zynqmp_ipi_message {
> +	size_t len;
> +	u8 data[0];
> +};
> +
> +#endif /* _LINUX_ZYNQMP_IPI_MESSAGE_H_ */
> --
> 2.7.4