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

Signed-off-by: Wendy Liang <jli...@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

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