remoteproc: xilinx: Add mailbox channels for rpmsg

This patch makes each r5 core mailbox client and uses
tx and rx channels to send and receive data to/from
remote processor respectively. This is needed for rpmsg
communication to remote processor.

Signed-off-by: Tanmay Shah <tanmay.shah@amd.com>
Link: https://lore.kernel.org/r/20230311012407.1292118-6-tanmay.shah@amd.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

diff --git a/drivers/remoteproc/xlnx_r5_remoteproc.c b/drivers/remoteproc/xlnx_r5_remoteproc.c
index 5dd0076..53e3e4b 100644 (file)
--- a/drivers/remoteproc/xlnx_r5_remoteproc.c
+++ b/drivers/remoteproc/xlnx_r5_remoteproc.c
@@ -8,16 +8,23 @@
 #include <linux/dma-mapping.h>
 #include <linux/firmware/xlnx-zynqmp.h>
 #include <linux/kernel.h>
+#include <linux/mailbox_client.h>
+#include <linux/mailbox/zynqmp-ipi-message.h>
 #include <linux/module.h>
 #include <linux/of_address.h>
 #include <linux/of_platform.h>
 #include <linux/of_reserved_mem.h>
 #include <linux/platform_device.h>
 #include <linux/remoteproc.h>
-#include <linux/slab.h>
 
 #include "remoteproc_internal.h"
 
+/* IPI buffer MAX length */
+#define IPI_BUF_LEN_MAX        32U
+
+/* RX mailbox client buffer max length */
+#define MBOX_CLIENT_BUF_MAX    (IPI_BUF_LEN_MAX + \
+                                sizeof(struct zynqmp_ipi_message))
 /*
  * settings for RPU cluster mode which
  * reflects possible values of xlnx,cluster-mode dt-property
@@ -43,6 +50,27 @@ struct mem_bank_data {
        char *bank_name;
 };
 
+/**
+ * struct mbox_info
+ *
+ * @rx_mc_buf: to copy data from mailbox rx channel
+ * @tx_mc_buf: to copy data to mailbox tx channel
+ * @r5_core: this mailbox's corresponding r5_core pointer
+ * @mbox_work: schedule work after receiving data from mailbox
+ * @mbox_cl: mailbox client
+ * @tx_chan: mailbox tx channel
+ * @rx_chan: mailbox rx channel
+ */
+struct mbox_info {
+       unsigned char rx_mc_buf[MBOX_CLIENT_BUF_MAX];
+       unsigned char tx_mc_buf[MBOX_CLIENT_BUF_MAX];
+       struct zynqmp_r5_core *r5_core;
+       struct work_struct mbox_work;
+       struct mbox_client mbox_cl;
+       struct mbox_chan *tx_chan;
+       struct mbox_chan *rx_chan;
+};
+
 /*
  * Hardcoded TCM bank values. This will be removed once TCM bindings are
  * accepted for system-dt specifications and upstreamed in linux kernel
@@ -63,6 +91,7 @@ static const struct mem_bank_data zynqmp_tcm_banks[] = {
  * @tcm_banks: array of each TCM bank data
  * @rproc: rproc handle
  * @pm_domain_id: RPU CPU power domain id
+ * @ipi: pointer to mailbox information
  */
 struct zynqmp_r5_core {
        struct device *dev;
@@ -71,6 +100,7 @@ struct zynqmp_r5_core {
        struct mem_bank_data **tcm_banks;
        struct rproc *rproc;
        u32 pm_domain_id;
+       struct mbox_info *ipi;
 };
 
 /**
@@ -88,6 +118,178 @@ struct zynqmp_r5_cluster {
        struct zynqmp_r5_core **r5_cores;
 };
 
+/**
+ * event_notified_idr_cb() - callback for vq_interrupt per notifyid
+ * @id: rproc->notify id
+ * @ptr: pointer to idr private data
+ * @data: data passed to idr_for_each callback
+ *
+ * Pass notification to remoteproc virtio
+ *
+ * Return: 0. having return is to satisfy the idr_for_each() function
+ *          pointer input argument requirement.
+ **/
+static int event_notified_idr_cb(int id, void *ptr, void *data)
+{
+       struct rproc *rproc = data;
+
+       if (rproc_vq_interrupt(rproc, id) == IRQ_NONE)
+               dev_dbg(&rproc->dev, "data not found for vqid=%d\n", id);
+
+       return 0;
+}
+
+/**
+ * handle_event_notified() - remoteproc notification work function
+ * @work: pointer to the work structure
+ *
+ * It checks each registered remoteproc notify IDs.
+ */
+static void handle_event_notified(struct work_struct *work)
+{
+       struct mbox_info *ipi;
+       struct rproc *rproc;
+
+       ipi = container_of(work, struct mbox_info, mbox_work);
+       rproc = ipi->r5_core->rproc;
+
+       /*
+        * We only use IPI for interrupt. The RPU firmware side may or may
+        * not write the notifyid when it trigger IPI.
+        * And thus, we scan through all the registered notifyids and
+        * find which one is valid to get the message.
+        * Even if message from firmware is NULL, we attempt to get vqid
+        */
+       idr_for_each(&rproc->notifyids, event_notified_idr_cb, rproc);
+}
+
+/**
+ * zynqmp_r5_mb_rx_cb() - receive channel mailbox callback
+ * @cl: mailbox client
+ * @msg: message pointer
+ *
+ * Receive data from ipi buffer, ack interrupt and then
+ * it will schedule the R5 notification work.
+ */
+static void zynqmp_r5_mb_rx_cb(struct mbox_client *cl, void *msg)
+{
+       struct zynqmp_ipi_message *ipi_msg, *buf_msg;
+       struct mbox_info *ipi;
+       size_t len;
+
+       ipi = container_of(cl, struct mbox_info, mbox_cl);
+
+       /* copy data from ipi buffer to r5_core */
+       ipi_msg = (struct zynqmp_ipi_message *)msg;
+       buf_msg = (struct zynqmp_ipi_message *)ipi->rx_mc_buf;
+       len = ipi_msg->len;
+       if (len > IPI_BUF_LEN_MAX) {
+               dev_warn(cl->dev, "msg size exceeded than %d\n",
+                        IPI_BUF_LEN_MAX);
+               len = IPI_BUF_LEN_MAX;
+       }
+       buf_msg->len = len;
+       memcpy(buf_msg->data, ipi_msg->data, len);
+
+       /* received and processed interrupt ack */
+       if (mbox_send_message(ipi->rx_chan, NULL) < 0)
+               dev_err(cl->dev, "ack failed to mbox rx_chan\n");
+
+       schedule_work(&ipi->mbox_work);
+}
+
+/**
+ * zynqmp_r5_setup_mbox() - Setup mailboxes related properties
+ *                         this is used for each individual R5 core
+ *
+ * @cdev: child node device
+ *
+ * Function to setup mailboxes related properties
+ * return : NULL if failed else pointer to mbox_info
+ */
+static struct mbox_info *zynqmp_r5_setup_mbox(struct device *cdev)
+{
+       struct mbox_client *mbox_cl;
+       struct mbox_info *ipi;
+
+       ipi = kzalloc(sizeof(*ipi), GFP_KERNEL);
+       if (!ipi)
+               return NULL;
+
+       mbox_cl = &ipi->mbox_cl;
+       mbox_cl->rx_callback = zynqmp_r5_mb_rx_cb;
+       mbox_cl->tx_block = false;
+       mbox_cl->knows_txdone = false;
+       mbox_cl->tx_done = NULL;
+       mbox_cl->dev = cdev;
+
+       /* Request TX and RX channels */
+       ipi->tx_chan = mbox_request_channel_byname(mbox_cl, "tx");
+       if (IS_ERR(ipi->tx_chan)) {
+               ipi->tx_chan = NULL;
+               kfree(ipi);
+               dev_warn(cdev, "mbox tx channel request failed\n");
+               return NULL;
+       }
+
+       ipi->rx_chan = mbox_request_channel_byname(mbox_cl, "rx");
+       if (IS_ERR(ipi->rx_chan)) {
+               mbox_free_channel(ipi->tx_chan);
+               ipi->rx_chan = NULL;
+               ipi->tx_chan = NULL;
+               kfree(ipi);
+               dev_warn(cdev, "mbox rx channel request failed\n");
+               return NULL;
+       }
+
+       INIT_WORK(&ipi->mbox_work, handle_event_notified);
+
+       return ipi;
+}
+
+static void zynqmp_r5_free_mbox(struct mbox_info *ipi)
+{
+       if (!ipi)
+               return;
+
+       if (ipi->tx_chan) {
+               mbox_free_channel(ipi->tx_chan);
+               ipi->tx_chan = NULL;
+       }
+
+       if (ipi->rx_chan) {
+               mbox_free_channel(ipi->rx_chan);
+               ipi->rx_chan = NULL;
+       }
+
+       kfree(ipi);
+}
+
+/*
+ * zynqmp_r5_core_kick() - kick a firmware if mbox is provided
+ * @rproc: r5 core's corresponding rproc structure
+ * @vqid: virtqueue ID
+ */
+static void zynqmp_r5_rproc_kick(struct rproc *rproc, int vqid)
+{
+       struct zynqmp_r5_core *r5_core = rproc->priv;
+       struct device *dev = r5_core->dev;
+       struct zynqmp_ipi_message *mb_msg;
+       struct mbox_info *ipi;
+       int ret;
+
+       ipi = r5_core->ipi;
+       if (!ipi)
+               return;
+
+       mb_msg = (struct zynqmp_ipi_message *)ipi->tx_mc_buf;
+       memcpy(mb_msg->data, &vqid, sizeof(vqid));
+       mb_msg->len = sizeof(vqid);
+       ret = mbox_send_message(ipi->tx_chan, mb_msg);
+       if (ret < 0)
+               dev_warn(dev, "failed to send message\n");
+}
+
 /*
  * zynqmp_r5_set_mode()
  *
@@ -624,6 +826,7 @@ static const struct rproc_ops zynqmp_r5_rproc_ops = {
        .find_loaded_rsc_table = rproc_elf_find_loaded_rsc_table,
        .sanity_check   = rproc_elf_sanity_check,
        .get_boot_addr  = rproc_elf_get_boot_addr,
+       .kick           = zynqmp_r5_rproc_kick,
 };
 
 /**
@@ -799,6 +1002,7 @@ static int zynqmp_r5_cluster_init(struct zynqmp_r5_cluster *cluster)
        struct device_node *child;
        enum rpu_tcm_comb tcm_mode;
        int core_count, ret, i;
+       struct mbox_info *ipi;
 
        ret = of_property_read_u32(dev_node, "xlnx,cluster-mode", &cluster_mode);
 
@@ -879,6 +1083,16 @@ static int zynqmp_r5_cluster_init(struct zynqmp_r5_cluster *cluster)
                }
 
                /*
+                * If mailbox nodes are disabled using "status" property then
+                * setting up mailbox channels will fail.
+                */
+               ipi = zynqmp_r5_setup_mbox(&child_pdev->dev);
+               if (ipi) {
+                       r5_cores[i]->ipi = ipi;
+                       ipi->r5_core = r5_cores[i];
+               }
+
+               /*
                 * If two child nodes are available in dts in lockstep mode,
                 * then ignore second child node.
                 */
@@ -915,6 +1129,7 @@ release_r5_cores:
        while (i >= 0) {
                put_device(child_devs[i]);
                if (r5_cores[i]) {
+                       zynqmp_r5_free_mbox(r5_cores[i]->ipi);
                        of_reserved_mem_device_release(r5_cores[i]->dev);
                        rproc_del(r5_cores[i]->rproc);
                        rproc_free(r5_cores[i]->rproc);
@@ -939,6 +1154,7 @@ static void zynqmp_r5_cluster_exit(void *data)
 
        for (i = 0; i < cluster->core_count; i++) {
                r5_core = cluster->r5_cores[i];
+               zynqmp_r5_free_mbox(r5_core->ipi);
                of_reserved_mem_device_release(r5_core->dev);
                put_device(r5_core->dev);
                rproc_del(r5_core->rproc);