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rpmsg: char: Add possibility to use default endpoint of the rpmsg device

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Current implementation create/destroy a new endpoint on each
rpmsg_eptdev_open/rpmsg_eptdev_release calls.

For a rpmsg device created by the NS announcement a default endpoint is created.
In this case we have to reuse the default rpmsg device endpoint associated to
the channel instead of creating a new one.

This patch prepares the introduction of a rpmsg channel device for the
char device. The rpmsg channel device will require a default endpoint to
communicate to the remote processor.

Add the default_ept field in rpmsg_eptdev structure.This pointer
determines the behavior on rpmsg_eptdev_open and rpmsg_eptdev_release call.

- If default_ept == NULL:
  Use the legacy behavior by creating a new endpoint each time
  rpmsg_eptdev_open is called and release it when rpmsg_eptdev_release
  is called on /dev/rpmsgX device open/close.

- If default_ept is set:
  use the rpmsg device default endpoint for the communication.

Add protection in rpmsg_eptdev_ioctl to prevent to destroy a default endpoint.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220124102524.295783-10-arnaud.pouliquen@foss.st.com
This commit is contained in:
Arnaud Pouliquen 2022-01-24 11:25:22 +01:00 committed by Bjorn Andersson
parent cc9da7de4a
commit bea9b79c2d
1 changed files with 19 additions and 2 deletions
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17
drivers/rpmsg/rpmsg_char.c
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@ -50,6 +50,8 @@ static DEFINE_IDA(rpmsg_minor_ida);
* @queue_lock: synchronization of @queue operations
* @queue: incoming message queue
* @readq: wait object for incoming queue
* @default_ept: set to channel default endpoint if the default endpoint should be re-used
* on device open to prevent endpoint address update.
*/
struct rpmsg_eptdev {
struct device dev;
@ -60,10 +62,12 @@ struct rpmsg_eptdev {
struct mutex ept_lock;
struct rpmsg_endpoint *ept;
struct rpmsg_endpoint *default_ept;
spinlock_t queue_lock;
struct sk_buff_head queue;
wait_queue_head_t readq;
};
int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data)
@ -121,7 +125,15 @@ static int rpmsg_eptdev_open(struct inode *inode, struct file *filp)
get_device(dev);
/*
* If the default_ept is set, the rpmsg device default endpoint is used.
* Else a new endpoint is created on open that will be destroyed on release.
*/
if (eptdev->default_ept)
ept = eptdev->default_ept;
else
ept = rpmsg_create_ept(rpdev, rpmsg_ept_cb, eptdev, eptdev->chinfo);
if (!ept) {
dev_err(dev, "failed to open %s\n", eptdev->chinfo.name);
put_device(dev);
@ -142,6 +154,7 @@ static int rpmsg_eptdev_release(struct inode *inode, struct file *filp)
/* Close the endpoint, if it's not already destroyed by the parent */
mutex_lock(&eptdev->ept_lock);
if (eptdev->ept) {
if (!eptdev->default_ept)
rpmsg_destroy_ept(eptdev->ept);
eptdev->ept = NULL;
}
@ -272,6 +285,10 @@ static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
if (cmd != RPMSG_DESTROY_EPT_IOCTL)
return -EINVAL;
/* Don't allow to destroy a default endpoint. */
if (eptdev->default_ept)
return -EINVAL;
return rpmsg_chrdev_eptdev_destroy(&eptdev->dev, NULL);
}