mailbox: ZynqMP IPI mailbox controller
authorWendy Liang <wendy.liang@xilinx.com>
Fri, 22 Feb 2019 00:36:33 +0000 (16:36 -0800)
committerJassi Brar <jaswinder.singh@linaro.org>
Thu, 7 Mar 2019 02:34:20 +0000 (20:34 -0600)
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>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
drivers/mailbox/Kconfig
drivers/mailbox/Makefile
drivers/mailbox/zynqmp-ipi-mailbox.c [new file with mode: 0644]
include/linux/mailbox/zynqmp-ipi-message.h [new file with mode: 0644]

index 3eeb12e93e986fd009818182a6a813645c14b5d9..d86e7a4ac04d1a79950a0ab20ef247a5ececc79a 100644 (file)
@@ -205,4 +205,15 @@ 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
+       bool "Xilinx ZynqMP IPI Mailbox"
+       depends on ARCH_ZYNQMP && OF
+       help
+         Say yes here to add support for Xilinx IPI mailbox driver.
+         This mailbox driver is used to send notification or short message
+         between processors with Xilinx ZynqMP IPI. It will place the
+         message to the IPI buffer and will access the IPI control
+         registers to kick the other processor or enquire status.
+
 endif
index c818b5d011aef28ae2e4632c3e93ff05f446590d..8be3bcbcf882bd0d0957406236ce58f007f1f5f6 100644 (file)
@@ -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 (file)
index 0000000..86887c9
--- /dev/null
@@ -0,0 +1,725 @@
+// 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_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
+ * @num_mboxes:           number of mailboxes of this IPI agent
+ * @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,
+                              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, 0, 0, 0, 0, res);
+       else
+               arm_smccc_hvc(a0, a1, a2, a3, 0, 0, 0, 0, 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;
+
+       (void)irq;
+       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, &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, &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;
+
+       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, &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;
+               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;
+
+       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;
+               }
+               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(ipi_mbox, arg0, 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_toio(mchan->resp_buf, msg->data, msg->len);
+               arg0 = SMC_IPI_MAILBOX_ACK;
+               zynqmp_ipi_fw_call(ipi_mbox, arg0, IPI_SMC_ACK_EIRQ_MASK,
+                                  &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, &res);
+               /* Check the SMC call status, a0 of the result */
+               ret = (int)(res.a0 & 0xFFFFFFFF);
+               if (ret < 0) {
+                       dev_err(dev, "SMC to open the IPI channel failed.\n");
+                       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, &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, &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, &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
+ *
+ * @dev: the ipi mailbox device
+ *
+ * This is to avoid the no device release() function kernel warning.
+ *
+ */
+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 = devm_mbox_controller_register(mdev, mbox);
+       if (ret)
+               dev_err(mdev,
+                       "Failed to register mbox_controller(%d)\n", ret);
+       else
+               dev_info(mdev,
+                        "Registered ZynqMP IPI mbox with TX/RX channels.\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 num_mboxes, ret = -EINVAL;
+
+       num_mboxes = of_get_child_count(np);
+       pdata = devm_kzalloc(dev, sizeof(*pdata) + (num_mboxes * 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 = num_mboxes;
+       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 (file)
index 0000000..9542b41
--- /dev/null
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _LINUX_ZYNQMP_IPI_MESSAGE_H_
+#define _LINUX_ZYNQMP_IPI_MESSAGE_H_
+
+/**
+ * struct zynqmp_ipi_message - ZynqMP IPI message structure
+ * @len:  Length of message
+ * @data: message payload
+ *
+ * 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_ */