rpmsg: Support drivers without primary endpoint

Some types of rpmsg drivers does not have a primary endpoint to tie
their existence upon, but wishes to create and destroy endpoints
dynamically, e.g. based on user interactions.

Allow rpmsg drivers to omit a driver callback to signal this case and
make the probe path not create a primary endpoint in this case.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

1 files changed, 18 insertions, 14 deletions

diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c
index 087d4db896c8..7561941ba413 100644
--- a/drivers/rpmsg/rpmsg_core.c
+++ b/drivers/rpmsg/rpmsg_core.c
@@ -347,27 +347,30 @@ static int rpmsg_dev_probe(struct device *dev)
         struct rpmsg_device *rpdev = to_rpmsg_device(dev);
         struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver);
         struct rpmsg_channel_info chinfo = {};
-        struct rpmsg_endpoint *ept;
+        struct rpmsg_endpoint *ept = NULL;
         int err;
 
-        strncpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE);
-        chinfo.src = rpdev->src;
-        chinfo.dst = RPMSG_ADDR_ANY;
+        if (rpdrv->callback) {
+                strncpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE);
+                chinfo.src = rpdev->src;
+                chinfo.dst = RPMSG_ADDR_ANY;
 
-        ept = rpmsg_create_ept(rpdev, rpdrv->callback, NULL, chinfo);
-        if (!ept) {
-                dev_err(dev, "failed to create endpoint\n");
-                err = -ENOMEM;
-                goto out;
-        }
+                ept = rpmsg_create_ept(rpdev, rpdrv->callback, NULL, chinfo);
+                if (!ept) {
+                        dev_err(dev, "failed to create endpoint\n");
+                        err = -ENOMEM;
+                        goto out;
+                }
 
-        rpdev->ept = ept;
-        rpdev->src = ept->addr;
+                rpdev->ept = ept;
+                rpdev->src = ept->addr;
+        }
 
         err = rpdrv->probe(rpdev);
         if (err) {
                 dev_err(dev, "%s: failed: %d\n", __func__, err);
-                rpmsg_destroy_ept(ept);
+                if (ept)
+                        rpmsg_destroy_ept(ept);
                 goto out;
         }
 
@@ -388,7 +391,8 @@ static int rpmsg_dev_remove(struct device *dev)
 
         rpdrv->remove(rpdev);
 
-        rpmsg_destroy_ept(rpdev->ept);
+        if (rpdev->ept)
+                rpmsg_destroy_ept(rpdev->ept);
 
         return err;
 }