linux-kernel - [PATCH v7 10/12] rpmsg: char: Introduce the "rpmsg-raw" channel

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Message-ID: <20211108141937.13016-11-arnaud.pouliquen@foss.st.com>
Date:   Mon, 8 Nov 2021 15:19:35 +0100
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>,
        <julien.massot@....bzh>, <arnaud.pouliquen@...s.st.com>
Subject: [PATCH v7 10/12] rpmsg: char: Introduce the "rpmsg-raw" channel

Allows to probe the endpoint device on a remote name service announcement,
by registering a rpmsg_driverfor the "rpmsg-raw" channel.

With this patch the /dev/rpmsgX interface can be instantiated by the remote
firmware.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@...s.st.com>
---
 drivers/rpmsg/rpmsg_char.c | 64 ++++++++++++++++++++++++++++++++++++++
 drivers/rpmsg/rpmsg_ctrl.c |  7 +++--
 2 files changed, 69 insertions(+), 2 deletions(-)

diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
index 6a01e8e1c111..dd754c870ba1 100644
--- a/drivers/rpmsg/rpmsg_char.c
+++ b/drivers/rpmsg/rpmsg_char.c
@@ -432,6 +432,58 @@ int rpmsg_chrdev_eptdev_create(struct rpmsg_device *rpdev, struct device *parent
 }
 EXPORT_SYMBOL(rpmsg_chrdev_eptdev_create);
 
+static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev)
+{
+	struct rpmsg_channel_info chinfo;
+	struct rpmsg_eptdev *eptdev;
+	struct device *dev = &rpdev->dev;
+
+	memcpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE);
+	chinfo.src = rpdev->src;
+	chinfo.dst = rpdev->dst;
+
+	eptdev = rpmsg_chrdev_eptdev_alloc(rpdev, dev);
+	if (IS_ERR(eptdev))
+		return PTR_ERR(eptdev);
+
+	/*
+	 * Create the default endpoint associated to the rpmsg device and provide rpmsg_eptdev
+	 * structure as callback private data.
+	 * Do not allow the creation and release of an endpoint on /dev/rpmsgX open and close,
+	 * reuse the default endpoint instead
+	 */
+	eptdev->default_ept = rpmsg_create_default_ept(rpdev, rpmsg_ept_cb, eptdev, chinfo);
+	if (!eptdev->default_ept) {
+		dev_err(&rpdev->dev, "failed to create %s\n", chinfo.name);
+		put_device(dev);
+		kfree(eptdev);
+		return -EINVAL;
+	}
+
+	return rpmsg_chrdev_eptdev_add(eptdev, chinfo);
+}
+
+static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
+{
+	int ret;
+
+	ret = device_for_each_child(&rpdev->dev, NULL, rpmsg_chrdev_eptdev_destroy);
+	if (ret)
+		dev_warn(&rpdev->dev, "failed to destroy endpoints: %d\n", ret);
+}
+
+static struct rpmsg_device_id rpmsg_chrdev_id_table[] = {
+	{ .name	= "rpmsg-raw" },
+	{ },
+};
+
+static struct rpmsg_driver rpmsg_chrdev_driver = {
+	.probe = rpmsg_chrdev_probe,
+	.remove = rpmsg_chrdev_remove,
+	.id_table = rpmsg_chrdev_id_table,
+	.drv.name = "rpmsg_chrdev",
+};
+
 static int rpmsg_chrdev_init(void)
 {
 	int ret;
@@ -442,12 +494,24 @@ static int rpmsg_chrdev_init(void)
 		return ret;
 	}
 
+	ret = register_rpmsg_driver(&rpmsg_chrdev_driver);
+	if (ret < 0) {
+		pr_err("rpmsg: failed to register rpmsg raw driver\n");
+		goto free_region;
+	}
+
 	return 0;
+
+free_region:
+	unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
+
+	return ret;
 }
 postcore_initcall(rpmsg_chrdev_init);
 
 static void rpmsg_chrdev_exit(void)
 {
+	unregister_rpmsg_driver(&rpmsg_chrdev_driver);
 	unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
 }
 module_exit(rpmsg_chrdev_exit);
diff --git a/drivers/rpmsg/rpmsg_ctrl.c b/drivers/rpmsg/rpmsg_ctrl.c
index 59d2bd264fdb..298e75dc7774 100644
--- a/drivers/rpmsg/rpmsg_ctrl.c
+++ b/drivers/rpmsg/rpmsg_ctrl.c
@@ -10,6 +10,9 @@
  * Based on rpmsg performance statistics driver by Michal Simek, which in turn
  * was based on TI & Google OMX rpmsg driver.
  */
+
+#define pr_fmt(fmt)		KBUILD_MODNAME ": " fmt
+
 #include <linux/cdev.h>
 #include <linux/device.h>
 #include <linux/fs.h>
@@ -193,13 +196,13 @@ static int rpmsg_ctrldev_init(void)
 
 	ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg_ctrl");
 	if (ret < 0) {
-		pr_err("rpmsg: failed to allocate char dev region\n");
+		pr_err("failed to allocate char dev region\n");
 		return ret;
 	}
 
 	ret = register_rpmsg_driver(&rpmsg_ctrldev_driver);
 	if (ret < 0) {
-		pr_err("rpmsg ctrl: failed to register rpmsg driver\n");
+		pr_err("failed to register rpmsg driver\n");
 		unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
 	}
 
-- 
2.17.1