From bea9b79c2d10fecf7bfa26e212ecefe61d232e39 Mon Sep 17 00:00:00 2001 From: Arnaud Pouliquen Date: Mon, 24 Jan 2022 11:25:22 +0100 Subject: [PATCH] rpmsg: char: Add possibility to use default endpoint of the rpmsg device 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 Signed-off-by: Bjorn Andersson Link: https://lore.kernel.org/r/20220124102524.295783-10-arnaud.pouliquen@foss.st.com --- drivers/rpmsg/rpmsg_char.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c index bf7311d64e42..8430d568fdd0 100644 --- a/drivers/rpmsg/rpmsg_char.c +++ b/drivers/rpmsg/rpmsg_char.c @@ -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); - ept = rpmsg_create_ept(rpdev, rpmsg_ept_cb, eptdev, eptdev->chinfo); + /* + * 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); @@ -142,7 +154,8 @@ 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) { - rpmsg_destroy_ept(eptdev->ept); + if (!eptdev->default_ept) + rpmsg_destroy_ept(eptdev->ept); eptdev->ept = NULL; } mutex_unlock(&eptdev->ept_lock); @@ -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); }