remoteproc: st: add virtio communication support

This patch provides virtio communication support based on mailbox
for ST co-processors.

Signed-off-by: Loic Pallardy <loic.pallardy@st.com>
Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

2 files changed, 114 insertions, 2 deletions

diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig
index 402de7089302..65f86bc24c07 100644
--- a/drivers/remoteproc/Kconfig
+++ b/drivers/remoteproc/Kconfig
@@ -118,6 +118,9 @@ config ST_REMOTEPROC
         tristate "ST remoteproc support"
         depends on ARCH_STI
         depends on REMOTEPROC
+        select MAILBOX
+        select STI_MBOX
+        select RPMSG_VIRTIO
         help
           Say y here to support ST's adjunct processors via the remote
           processor framework.
diff --git a/drivers/remoteproc/st_remoteproc.c b/drivers/remoteproc/st_remoteproc.c
index 1468ba213811..d534bf23dc56 100644
--- a/drivers/remoteproc/st_remoteproc.c
+++ b/drivers/remoteproc/st_remoteproc.c
@@ -15,6 +15,7 @@
 #include <linux/err.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
+#include <linux/mailbox_client.h>
 #include <linux/mfd/syscon.h>
 #include <linux/module.h>
 #include <linux/of.h>
@@ -25,6 +26,16 @@
 #include <linux/remoteproc.h>
 #include <linux/reset.h>
 
+#include "remoteproc_internal.h"
+
+#define ST_RPROC_VQ0            0
+#define ST_RPROC_VQ1            1
+#define ST_RPROC_MAX_VRING      2
+
+#define MBOX_RX                 0
+#define MBOX_TX                 1
+#define MBOX_MAX                2
+
 struct st_rproc_config {
         bool                    sw_reset;
         bool                    pwr_reset;
@@ -39,8 +50,47 @@ struct st_rproc {
         u32                     clk_rate;
         struct regmap           *boot_base;
         u32                     boot_offset;
+        struct mbox_chan        *mbox_chan[ST_RPROC_MAX_VRING * MBOX_MAX];
+        struct mbox_client mbox_client_vq0;
+        struct mbox_client mbox_client_vq1;
 };
 
+static void st_rproc_mbox_callback(struct device *dev, u32 msg)
+{
+        struct rproc *rproc = dev_get_drvdata(dev);
+
+        if (rproc_vq_interrupt(rproc, msg) == IRQ_NONE)
+                dev_dbg(dev, "no message was found in vqid %d\n", msg);
+}
+
+static
+void st_rproc_mbox_callback_vq0(struct mbox_client *mbox_client, void *data)
+{
+        st_rproc_mbox_callback(mbox_client->dev, 0);
+}
+
+static
+void st_rproc_mbox_callback_vq1(struct mbox_client *mbox_client, void *data)
+{
+        st_rproc_mbox_callback(mbox_client->dev, 1);
+}
+
+static void st_rproc_kick(struct rproc *rproc, int vqid)
+{
+        struct st_rproc *ddata = rproc->priv;
+        struct device *dev = rproc->dev.parent;
+        int ret;
+
+        /* send the index of the triggered virtqueue in the mailbox payload */
+        if (WARN_ON(vqid >= ST_RPROC_MAX_VRING))
+                return;
+
+        ret = mbox_send_message(ddata->mbox_chan[vqid * MBOX_MAX + MBOX_TX],
+                                (void *)&vqid);
+        if (ret < 0)
+                dev_err(dev, "failed to send message via mbox: %d\n", ret);
+}
+
 static int st_rproc_start(struct rproc *rproc)
 {
         struct st_rproc *ddata = rproc->priv;
@@ -108,6 +158,7 @@ static int st_rproc_stop(struct rproc *rproc)
 }
 
 static const struct rproc_ops st_rproc_ops = {
+        .kick           = st_rproc_kick,
         .start          = st_rproc_start,
         .stop           = st_rproc_stop,
 };
@@ -221,8 +272,9 @@ static int st_rproc_probe(struct platform_device *pdev)
         struct st_rproc *ddata;
         struct device_node *np = dev->of_node;
         struct rproc *rproc;
+        struct mbox_chan *chan;
         int enabled;
-        int ret;
+        int ret, i;
 
         match = of_match_device(st_rproc_match, dev);
         if (!match || !match->data) {
@@ -257,12 +309,65 @@ static int st_rproc_probe(struct platform_device *pdev)
                 clk_set_rate(ddata->clk, ddata->clk_rate);
         }
 
+        if (of_get_property(np, "mbox-names", NULL)) {
+                ddata->mbox_client_vq0.dev              = dev;
+                ddata->mbox_client_vq0.tx_done          = NULL;
+                ddata->mbox_client_vq0.tx_block = false;
+                ddata->mbox_client_vq0.knows_txdone     = false;
+                ddata->mbox_client_vq0.rx_callback      = st_rproc_mbox_callback_vq0;
+
+                ddata->mbox_client_vq1.dev              = dev;
+                ddata->mbox_client_vq1.tx_done          = NULL;
+                ddata->mbox_client_vq1.tx_block = false;
+                ddata->mbox_client_vq1.knows_txdone     = false;
+                ddata->mbox_client_vq1.rx_callback      = st_rproc_mbox_callback_vq1;
+
+                /*
+                 * To control a co-processor without IPC mechanism.
+                 * This driver can be used without mbox and rpmsg.
+                 */
+                chan = mbox_request_channel_byname(&ddata->mbox_client_vq0, "vq0_rx");
+                if (IS_ERR(chan)) {
+                        dev_err(&rproc->dev, "failed to request mbox chan 0\n");
+                        ret = PTR_ERR(chan);
+                        goto free_clk;
+                }
+                ddata->mbox_chan[ST_RPROC_VQ0 * MBOX_MAX + MBOX_RX] = chan;
+
+                chan = mbox_request_channel_byname(&ddata->mbox_client_vq0, "vq0_tx");
+                if (IS_ERR(chan)) {
+                        dev_err(&rproc->dev, "failed to request mbox chan 0\n");
+                        ret = PTR_ERR(chan);
+                        goto free_mbox;
+                }
+                ddata->mbox_chan[ST_RPROC_VQ0 * MBOX_MAX + MBOX_TX] = chan;
+
+                chan = mbox_request_channel_byname(&ddata->mbox_client_vq1, "vq1_rx");
+                if (IS_ERR(chan)) {
+                        dev_err(&rproc->dev, "failed to request mbox chan 1\n");
+                        ret = PTR_ERR(chan);
+                        goto free_mbox;
+                }
+                ddata->mbox_chan[ST_RPROC_VQ1 * MBOX_MAX + MBOX_RX] = chan;
+
+                chan = mbox_request_channel_byname(&ddata->mbox_client_vq1, "vq1_tx");
+                if (IS_ERR(chan)) {
+                        dev_err(&rproc->dev, "failed to request mbox chan 1\n");
+                        ret = PTR_ERR(chan);
+                        goto free_mbox;
+                }
+                ddata->mbox_chan[ST_RPROC_VQ1 * MBOX_MAX + MBOX_TX] = chan;
+        }
+
         ret = rproc_add(rproc);
         if (ret)
-                goto free_clk;
+                goto free_mbox;
 
         return 0;
 
+free_mbox:
+        for (i = 0; i < ST_RPROC_MAX_VRING * MBOX_MAX; i++)
+                mbox_free_channel(ddata->mbox_chan[i]);
 free_clk:
         clk_unprepare(ddata->clk);
 free_rproc:
@@ -274,6 +379,7 @@ static int st_rproc_remove(struct platform_device *pdev)
 {
         struct rproc *rproc = platform_get_drvdata(pdev);
         struct st_rproc *ddata = rproc->priv;
+        int i;
 
         rproc_del(rproc);
 
@@ -281,6 +387,9 @@ static int st_rproc_remove(struct platform_device *pdev)
 
         of_reserved_mem_device_release(&pdev->dev);
 
+        for (i = 0; i < ST_RPROC_MAX_VRING * MBOX_MAX; i++)
+                mbox_free_channel(ddata->mbox_chan[i]);
+
         rproc_free(rproc);
 
         return 0;