From: Wendy Liang <wendy.liang@xilinx.com>
To: <jassisinghbrar@gmail.com>, <michal.simek@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>, Wendy Liang <jliang@xilinx.com>
Subject: [RFC v2 1/2] mailbox: ZynqMP IPI mailbox controller
Date: Sun, 3 Dec 2017 22:25:34 -0800
Message-ID: <1512368735-27147-2-git-send-email-jliang@xilinx.com>
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This patch is to introduce ZynqMP IPI mailbox controller driver
to use the ZynqMP IPI block as mailboxes.

Signed-off-by: Wendy Liang <jliang@xilinx.com>
---
 drivers/mailbox/Kconfig                    |   8 +
 drivers/mailbox/Makefile                   |   2 +
 drivers/mailbox/zynqmp-ipi-mailbox.c       | 633 +++++++++++++++++++++++++++++
 include/linux/mailbox/zynqmp-ipi-message.h |  24 ++
 4 files changed, 667 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 ba2f152..876614a 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig
@@ -171,4 +171,12 @@ config BCM_FLEXRM_MBOX
 	  Mailbox implementation of the Broadcom FlexRM ring manager,
 	  which provides access to various offload engines on Broadcom
 	  SoCs. Say Y here if you want to use the Broadcom FlexRM.
+
+config ZYNQMP_IPI_MBOX
+	tristate "Xilinx ZynqMP IPI Mailbox"
+	depends on ARCH_ZYNQMP && OF
+	help
+	  Mailbox implementation for Xilinx ZynqMP IPI. It is used to send
+	  notification or short message between processors with Xilinx
+	  ZynqMP IPI.
 endif
diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
index 4896f8d..155f72f 100644
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile
@@ -36,3 +36,5 @@ obj-$(CONFIG_BCM_FLEXRM_MBOX)	+= bcm-flexrm-mailbox.o
 obj-$(CONFIG_QCOM_APCS_IPC)	+= qcom-apcs-ipc-mailbox.o
 
 obj-$(CONFIG_TEGRA_HSP_MBOX)	+= tegra-hsp.o
+
+obj-$(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..334f5e1
--- /dev/null
+++ b/drivers/mailbox/zynqmp-ipi-mailbox.c
@@ -0,0 +1,633 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Xilinx Inter Processor Interrupt(IPI) Mailbox Driver
+ *
+ * Copyright (C) 2017 Xilinx Inc.
+ *
+ */
+
+#define pr_fmt(fmt) "%s: " fmt, __func__
+
+#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_device.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/arm-smccc.h>
+#include <linux/delay.h>
+#include <linux/mailbox/zynqmp-ipi-message.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
+ * @chan_type: channel type
+ */
+struct zynqmp_ipi_mchan {
+	int is_opened;
+	void __iomem *req_buf;
+	void __iomem *resp_buf;
+	size_t req_buf_size;
+	size_t resp_buf_size;
+	unsigned int chan_type;
+};
+
+/**
+ * struct zynqmp_ipi_mbox_pdata - Description of a ZynqMP IPI mailbox
+ *                                platform data.
+ * @dev:                  device pointer corresponding to the Xilinx ZynqMP
+ *                        IPI mailbox
+ * @local_id:             local IPI agent ID
+ * @remote_id:            remote IPI agent ID
+ * @method:               IPI SMC or HVC is going to be used
+ * @mbox:                 mailbox Controller
+ * @mchans:               array for channels, tx channel and rx channel.
+ * @irq:                  IPI agent interrupt ID
+ * @lock:                 IPI mailbox platform data lock
+ */
+struct zynqmp_ipi_mbox_pdata {
+	struct device *dev;
+	u32 local_id;
+	u32 remote_id;
+	unsigned int method;
+	struct mbox_controller mbox;
+	struct zynqmp_ipi_mchan mchans[2];
+	int irq;
+	spinlock_t lock; /* spin lock for local data */
+};
+
+static void zynqmp_ipi_fw_call(struct zynqmp_ipi_mbox_pdata *pdata,
+			       unsigned long a0, unsigned long a3,
+			       unsigned long a4, unsigned long a5,
+			       unsigned long a6, unsigned long a7,
+			       struct arm_smccc_res *res)
+{
+	unsigned long a1, a2;
+
+	a1 = pdata->local_id;
+	a2 = pdata->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_mbox_pdata *pdata = data;
+	struct mbox_chan *chan;
+	struct zynqmp_ipi_mchan *mchan;
+	struct zynqmp_ipi_message msg;
+	u64 arg0, arg3;
+	struct arm_smccc_res res;
+	int ret;
+
+	arg0 = SMC_IPI_MAILBOX_STATUS_ENQUIRY;
+	arg3 = IPI_SMC_ENQUIRY_DIRQ_MASK;
+	zynqmp_ipi_fw_call(pdata, arg0, arg3, 0, 0, 0, 0, &res);
+	ret = (int)(res.a0 & 0xFFFFFFFF);
+	if (ret > 0 && ret & IPI_MB_STATUS_RECV_PENDING) {
+		chan = &pdata->mbox.chans[IPI_MB_CHNL_RX];
+		mchan = chan->con_priv;
+		if (mchan->is_opened) {
+			msg.len = mchan->req_buf_size;
+			msg.data = mchan->req_buf;
+			/* Client will direclty copy data from
+			 * IPI buffer to client data memory
+			 */
+			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_pdata *pdata = dev_get_drvdata(dev);
+	struct zynqmp_ipi_mchan *mchan = chan->con_priv;
+	int ret;
+	u64 arg0;
+	struct arm_smccc_res res;
+
+	if (WARN_ON(!pdata)) {
+		dev_err(dev, "no platform drv data??\n");
+		return false;
+	}
+
+	arg0 = SMC_IPI_MAILBOX_STATUS_ENQUIRY;
+	zynqmp_ipi_fw_call(pdata, 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_pdata *pdata = 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(!pdata)) {
+		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(pdata, 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.len = mchan->resp_buf_size;
+		msg.data = mchan->resp_buf;
+		/* Client will direclty copy data from
+		 * IPI buffer to client data memory
+		 */
+		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_pdata *pdata = 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(!pdata)) {
+		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->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;
+		}
+		/* Enquire if the mailbox is free to send message */
+		arg0 = SMC_IPI_MAILBOX_STATUS_ENQUIRY;
+		timeout = 10;
+		do {
+			zynqmp_ipi_fw_call(pdata, 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, "channel %d sending msg timesout.\n",
+				 pdata->remote_id);
+			return -ETIME;
+		}
+		/* Copy message to the request buffer */
+		if (msg && msg->len)
+			memcpy_toio(mchan->req_buf, msg->data, msg->len);
+		/* Kick IPI mailbox to send message */
+		arg0 = SMC_IPI_MAILBOX_NOTIFY;
+		zynqmp_ipi_fw_call(pdata, 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(pdata, 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_pdata *pdata = dev_get_drvdata(dev);
+	struct zynqmp_ipi_mchan *mchan = chan->con_priv;
+	u64 arg0;
+	struct arm_smccc_res res;
+	int ret = 0;
+	unsigned long flags;
+	unsigned int nchan_type;
+
+	spin_lock_irqsave(&pdata->lock, flags);
+	if (mchan->is_opened) {
+		spin_unlock_irqrestore(&pdata->lock, flags);
+		return 0;
+	}
+
+	/* If no channel has been opened, open the IPI mailbox */
+	nchan_type = (mchan->chan_type + 1) % 2;
+	if (!pdata->mchans[nchan_type].is_opened) {
+		arg0 = SMC_IPI_MAILBOX_OPEN;
+		zynqmp_ipi_fw_call(pdata, 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;
+			spin_unlock_irqrestore(&pdata->lock, flags);
+			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(pdata, arg0, 0, 0, 0, 0, 0, &res);
+	}
+	mchan->is_opened = 1;
+	spin_unlock_irqrestore(&pdata->lock, flags);
+
+	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_pdata *pdata = dev_get_drvdata(dev);
+	struct zynqmp_ipi_mchan *mchan = chan->con_priv;
+	u64 arg0;
+	struct arm_smccc_res res;
+	unsigned long flags;
+	unsigned int chan_type;
+
+	spin_lock_irqsave(&pdata->lock, flags);
+	if (!mchan->is_opened) {
+		spin_unlock_irqrestore(&pdata->lock, flags);
+		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(pdata, arg0, 0, 0, 0, 0, 0, &res);
+	}
+	/* Release IPI mailbox if no other channel is opened */
+	chan_type = (chan_type + 1) % 2;
+	if (!pdata->mchans[chan_type].is_opened) {
+		arg0 = SMC_IPI_MAILBOX_RELEASE;
+		zynqmp_ipi_fw_call(pdata, arg0, 0, 0, 0, 0, 0, &res);
+	}
+
+	mchan->is_opened = 0;
+	spin_unlock_irqrestore(&pdata->lock, flags);
+}
+
+/* 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 zynqmp_ipi_mbox_pdata *pdata;
+	struct mbox_chan *chan;
+	struct device *dev = mbox->dev;
+	unsigned int chan_type;
+
+	pdata = container_of(mbox, struct zynqmp_ipi_mbox_pdata, mbox);
+
+	/* 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);
+
+static int zynqmp_ipi_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = pdev->dev.of_node;
+	struct zynqmp_ipi_mbox_pdata *pdata;
+	struct zynqmp_ipi_mchan *mchan;
+	struct mbox_chan *chans;
+	struct mbox_controller *mbox;
+	const unsigned char *prop;
+	struct resource *res;
+	int ret = -EINVAL;
+
+	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
+	if (!pdata)
+		return -ENOMEM;
+
+	pdata->dev = dev;
+
+	mchan = &pdata->mchans[IPI_MB_CHNL_TX];
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
+					   "local_request_region");
+	if (res) {
+		mchan->req_buf_size = resource_size(res);
+		mchan->req_buf = devm_ioremap(&pdev->dev, res->start,
+					      mchan->req_buf_size);
+		if (IS_ERR(mchan->req_buf)) {
+			dev_err(dev, "Unable to map IPI buffer I/O memory\n");
+			ret = PTR_ERR(mchan->req_buf);
+			return ret;
+		}
+	}
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
+					   "remote_response_region");
+	if (res) {
+		mchan->resp_buf_size = resource_size(res);
+		mchan->resp_buf = devm_ioremap(&pdev->dev, res->start,
+					       mchan->resp_buf_size);
+		if (IS_ERR(mchan->resp_buf)) {
+			dev_err(dev, "Unable to map IPI buffer I/O memory\n");
+			ret = PTR_ERR(mchan->resp_buf);
+			return ret;
+		}
+	}
+
+	mchan = &pdata->mchans[IPI_MB_CHNL_RX];
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
+					   "remote_request_region");
+	if (res) {
+		mchan->req_buf_size = resource_size(res);
+		mchan->req_buf = devm_ioremap(&pdev->dev, res->start,
+					      mchan->req_buf_size);
+		if (IS_ERR(mchan->req_buf)) {
+			dev_err(dev, "Unable to map IPI buffer I/O memory\n");
+			ret = PTR_ERR(mchan->req_buf);
+			return ret;
+		}
+	}
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
+					   "local_response_region");
+	if (res) {
+		mchan->resp_buf_size = resource_size(res);
+		mchan->resp_buf = devm_ioremap(&pdev->dev, res->start,
+					       mchan->resp_buf_size);
+		if (IS_ERR(mchan->resp_buf)) {
+			dev_err(dev, "Unable to map IPI buffer I/O memory\n");
+			ret = PTR_ERR(mchan->resp_buf);
+			return ret;
+		}
+	}
+
+	/* Get the IPI local and remote agents IDs */
+	ret = of_property_read_u32_index(np, "xlnx,ipi-ids", 0,
+					 &pdata->local_id);
+	if (ret < 0) {
+		dev_err(dev, "No IPI local ID is specified.\n");
+		return ret;
+	}
+	ret = of_property_read_u32_index(np, "xlnx,ipi-ids", 1,
+					 &pdata->remote_id);
+	if (ret < 0) {
+		dev_err(dev, "No IPI remote ID is specified.\n");
+		return ret;
+	}
+
+	/* Get how to access IPI agent method */
+	prop = of_get_property(np, "method", NULL);
+	if (!prop) {
+		pdata->method = USE_SMC;
+	} else if (!strcmp(prop, "smc")) {
+		pdata->method = USE_SMC;
+	} else if (!strcmp(prop, "hvc")) {
+		pdata->method = USE_HVC;
+	} else {
+		dev_err(dev, "Invalid \"method\" %s.\n", prop);
+		return ret;
+	}
+
+	/* IPI IRQ */
+	ret = platform_get_irq(pdev, 0);
+	if (ret < 0) {
+		dev_err(dev, "unable to find IPI IRQ.\n");
+		return ret;
+	}
+	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);
+		return ret;
+	}
+
+	mbox = &pdata->mbox;
+	mbox->dev = dev;
+	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(dev, 2 * sizeof(*chans), GFP_KERNEL);
+	if (!chans)
+		return -ENOMEM;
+	mbox->chans = chans;
+	mbox->chans[IPI_MB_CHNL_TX].con_priv = &pdata->mchans[IPI_MB_CHNL_TX];
+	mbox->chans[IPI_MB_CHNL_RX].con_priv = &pdata->mchans[IPI_MB_CHNL_RX];
+	pdata->mchans[IPI_MB_CHNL_TX].chan_type = IPI_MB_CHNL_TX;
+	pdata->mchans[IPI_MB_CHNL_RX].chan_type = IPI_MB_CHNL_RX;
+	spin_lock_init(&pdata->lock);
+	platform_set_drvdata(pdev, pdata);
+	ret = mbox_controller_register(mbox);
+	if (ret)
+		dev_err(dev, "Failed to register mbox_controller(%d)\n", ret);
+	else
+		dev_info(dev, "Probed ZynqMP IPI Mailbox driver.\n");
+	return ret;
+}
+
+static int zynqmp_ipi_remove(struct platform_device *pdev)
+{
+	struct zynqmp_ipi_mbox_pdata *pdata;
+
+	pdata = platform_get_drvdata(pdev);
+	mbox_controller_unregister(&pdata->mbox);
+
+	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 struct class zynqmp_ipi_class = { .name = "zynqmp_ipi_mbox", };
+
+static int __init zynqmp_ipi_init(void)
+{
+	int err;
+
+	err = class_register(&zynqmp_ipi_class);
+	if (err)
+		return err;
+
+	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);
+	class_unregister(&zynqmp_ipi_class);
+}
+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..173c41d
--- /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 pointer
+ *
+ * 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;
+};
+
+#endif /* _LINUX_ZYNQMP_IPI_MESSAGE_H_ */
-- 
2.7.4