linux-kernel - [PATCH v2 6/7] rpmsg: char: No dynamic endpoint management for the default one

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Message-ID: <20210413134458.17912-7-arnaud.pouliquen@foss.st.com>
Date:   Tue, 13 Apr 2021 15:44:57 +0200
From:   Arnaud Pouliquen <arnaud.pouliquen@...s.st.com>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>,
        Ohad Ben-Cohen <ohad@...ery.com>,
        Mathieu Poirier <mathieu.poirier@...aro.org>
CC:     <linux-remoteproc@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <arnaud.pouliquen@...s.st.com>
Subject: [PATCH v2 6/7] rpmsg: char: No dynamic endpoint management for the default one

Do not dynamically manage the default endpoint associated to the rpmsg
device. The ept address must not change.

This update is needed to manage the rpmsg-raw channel. In this
case a default endpoint is used and its address must not change or
been reused by another service.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@...s.st.com>
---
 drivers/rpmsg/rpmsg_char.c | 28 +++++++++++++++++++++-------
 1 file changed, 21 insertions(+), 7 deletions(-)

diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
index 4606787b7011..fa59abfa8878 100644
--- a/drivers/rpmsg/rpmsg_char.c
+++ b/drivers/rpmsg/rpmsg_char.c
@@ -112,17 +112,26 @@ static int rpmsg_eptdev_open(struct inode *inode, struct file *filp)
 	struct rpmsg_endpoint *ept;
 	struct rpmsg_device *rpdev = eptdev->rpdev;
 	struct device *dev = &eptdev->dev;
+	u32 addr = eptdev->chinfo.src;
 
 	if (eptdev->ept)
 		return -EBUSY;
 
 	get_device(dev);
 
-	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);
-		return -EINVAL;
+	/*
+	 * The RPMsg device can has been created by a ns announcement. In this
+	 * case a default endpoint has been created. Reuse it to avoid to manage
+	 * a new address on each open/close.
+	 */
+	ept = rpdev->ept;
+	if (!ept || addr != ept->addr) {
+		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);
+			return -EINVAL;
+		}
 	}
 
 	eptdev->ept = ept;
@@ -134,12 +143,17 @@ static int rpmsg_eptdev_open(struct inode *inode, struct file *filp)
 static int rpmsg_eptdev_release(struct inode *inode, struct file *filp)
 {
 	struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev);
+	struct rpmsg_device *rpdev = eptdev->rpdev;
 	struct device *dev = &eptdev->dev;
 
-	/* Close the endpoint, if it's not already destroyed by the parent */
+	/*
+	 * Close the endpoint, if it's not already destroyed by the parent and it is not the
+	 * default one.
+	 */
 	mutex_lock(&eptdev->ept_lock);
 	if (eptdev->ept) {
-		rpmsg_destroy_ept(eptdev->ept);
+		if (eptdev->ept != rpdev->ept)
+			rpmsg_destroy_ept(eptdev->ept);
 		eptdev->ept = NULL;
 	}
 	mutex_unlock(&eptdev->ept_lock);
-- 
2.17.1