rpmsg: ctrl: Introduce new RPMSG_CREATE/RELEASE_DEV_IOCTL controls

Allow the user space application to create and release an rpmsg device
by adding RPMSG_CREATE_DEV_IOCTL and RPMSG_RELEASE_DEV_IOCTL ioctrls to
the /dev/rpmsg_ctrl interface

The RPMSG_CREATE_DEV_IOCTL Ioctl can be used to instantiate a local rpmsg
device.
Depending on the back-end implementation, the associated rpmsg driver is
probed and a NS announcement can be sent to the remote processor.

The RPMSG_RELEASE_DEV_IOCTL allows the user application to release a
rpmsg device created either by the remote processor or with the
RPMSG_CREATE_DEV_IOCTL call.
Depending on the back-end implementation, the associated rpmsg driver is
removed and a NS destroy rpmsg can be sent to the remote processor.

Suggested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220124102524.295783-12-arnaud.pouliquen@foss.st.com

diff --git a/drivers/rpmsg/rpmsg_ctrl.c b/drivers/rpmsg/rpmsg_ctrl.c
index f43b5e4..107da70 100644 (file)
--- a/drivers/rpmsg/rpmsg_ctrl.c
+++ b/drivers/rpmsg/rpmsg_ctrl.c
@@ -43,11 +43,13 @@ static DEFINE_IDA(rpmsg_minor_ida);
  * @rpdev:     underlaying rpmsg device
  * @cdev:      cdev for the ctrl device
  * @dev:       device for the ctrl device
+ * @ctrl_lock: serialize the ioctrls.
  */
 struct rpmsg_ctrldev {
        struct rpmsg_device *rpdev;
        struct cdev cdev;
        struct device dev;
+       struct mutex ctrl_lock;
 };
 
 static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp)
@@ -76,9 +78,8 @@ static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
        void __user *argp = (void __user *)arg;
        struct rpmsg_endpoint_info eptinfo;
        struct rpmsg_channel_info chinfo;
-
-       if (cmd != RPMSG_CREATE_EPT_IOCTL)
-               return -EINVAL;
+       struct rpmsg_device *rpdev;
+       int ret = 0;
 
        if (copy_from_user(&eptinfo, argp, sizeof(eptinfo)))
                return -EFAULT;
@@ -88,7 +89,33 @@ static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
        chinfo.src = eptinfo.src;
        chinfo.dst = eptinfo.dst;
 
-       return rpmsg_chrdev_eptdev_create(ctrldev->rpdev, &ctrldev->dev, chinfo);
+       mutex_lock(&ctrldev->ctrl_lock);
+       switch (cmd) {
+       case RPMSG_CREATE_EPT_IOCTL:
+               ret = rpmsg_chrdev_eptdev_create(ctrldev->rpdev, &ctrldev->dev, chinfo);
+               break;
+
+       case RPMSG_CREATE_DEV_IOCTL:
+               rpdev = rpmsg_create_channel(ctrldev->rpdev, &chinfo);
+               if (!rpdev) {
+                       dev_err(&ctrldev->dev, "failed to create %s channel\n", chinfo.name);
+                       ret = -ENXIO;
+               }
+               break;
+
+       case RPMSG_RELEASE_DEV_IOCTL:
+               ret = rpmsg_release_channel(ctrldev->rpdev, &chinfo);
+               if (ret)
+                       dev_err(&ctrldev->dev, "failed to release %s channel (%d)\n",
+                               chinfo.name, ret);
+               break;
+
+       default:
+               ret = -EINVAL;
+       }
+       mutex_unlock(&ctrldev->ctrl_lock);
+
+       return ret;
 };
 
 static const struct file_operations rpmsg_ctrldev_fops = {
@@ -125,6 +152,7 @@ static int rpmsg_ctrldev_probe(struct rpmsg_device *rpdev)
        dev->parent = &rpdev->dev;
        dev->class = rpmsg_class;
 
+       mutex_init(&ctrldev->ctrl_lock);
        cdev_init(&ctrldev->cdev, &rpmsg_ctrldev_fops);
        ctrldev->cdev.owner = THIS_MODULE;
 

diff --git a/include/uapi/linux/rpmsg.h b/include/uapi/linux/rpmsg.h
index f5ca874..1637e68 100644 (file)
--- a/include/uapi/linux/rpmsg.h
+++ b/include/uapi/linux/rpmsg.h
@@ -33,4 +33,14 @@ struct rpmsg_endpoint_info {
  */
 #define RPMSG_DESTROY_EPT_IOCTL        _IO(0xb5, 0x2)
 
+/**
+ * Instantiate a new local rpmsg service device.
+ */
+#define RPMSG_CREATE_DEV_IOCTL _IOW(0xb5, 0x3, struct rpmsg_endpoint_info)
+
+/**
+ * Release a local rpmsg device.
+ */
+#define RPMSG_RELEASE_DEV_IOCTL        _IOW(0xb5, 0x4, struct rpmsg_endpoint_info)
+
 #endif