[PATCH v2 0/7] Restructure the rpmsg char and introduce the rpmsg-raw channel

[PATCH v2 0/7] Restructure the rpmsg char and introduce the rpmsg-raw channel

[Arnaud Pouliquen]

update from V1 [1]
 - fix issues reported by Mathieu Poirier

This series is the second step in the division of the series [2]: 
"Introducing a Generic IOCTL Interface for RPMsg Channel Management".

The purpose of this patchset is to:
- split the control code related to the control
  and the endpoint. 
- define the rpmsg-raw channel, associated with the rpmsg char device to
  allow it to be instantiated using a name service announcement.
    
An important point to keep in mind for this patchset is that the concept of
channel is associated with a default endpoint. To facilitate communication
with the remote side, this default endpoint must have a fixed address.

Consequently, for this series, I made a design choice to fix the endpoint
on the "rpmsg-raw" channel probe, and not allow to create/destroy an endpoint
on FS open/close.

This is only applicable for channels probed by the rpmsg bus. The behavior,
using the RPMSG_CREATE_EPT_IOCTL and RPMSG_DESTROY_EPT_IOCTL controls, is
preserved.
  
The next steps should be to correct this:
Introduce the IOCTLs RPMSG_CREATE_DEV_IOCTL and RPMSG_DESTROY_DEV_IOCTL
to instantiate the rpmsg devices

[1]: https://patchwork.kernel.org/project/linux-remoteproc/list/?series=453805
[2]: https://patchwork.kernel.org/project/linux-remoteproc/list/?series=435523

Arnaud Pouliquen (7):
  rpmsg: char: Export eptdev create an destroy functions
  rpmsg: Move the rpmsg control device from rpmsg_char to rpmsg_ctrl
  rpmsg: Update rpmsg_chrdev_register_device function
  rpmsg: char: Introduce __rpmsg_chrdev_create_eptdev function
  rpmsg: char: Introduce a rpmsg driver for the rpmsg char device
  rpmsg: char: No dynamic endpoint management for the default one
  rpmsg: char: Return error if user tries to destroy a default endpoint.

 drivers/rpmsg/Kconfig             |   9 ++
 drivers/rpmsg/Makefile            |   1 +
 drivers/rpmsg/qcom_glink_native.c |   2 +-
 drivers/rpmsg/qcom_smd.c          |   2 +-
 drivers/rpmsg/rpmsg_char.c        | 222 +++++++++-------------------
 drivers/rpmsg/rpmsg_char.h        |  52 +++++++
 drivers/rpmsg/rpmsg_ctrl.c        | 231 ++++++++++++++++++++++++++++++
 drivers/rpmsg/rpmsg_internal.h    |   8 +-
 drivers/rpmsg/virtio_rpmsg_bus.c  |   2 +-
 9 files changed, 368 insertions(+), 161 deletions(-)
 create mode 100644 drivers/rpmsg/rpmsg_char.h
 create mode 100644 drivers/rpmsg/rpmsg_ctrl.c

-- 
2.17.1

[PATCH v2 1/7] rpmsg: char: Export eptdev create an destroy functions

[Arnaud Pouliquen]

To prepare the split of the code related to the control (ctrldev)
and the endpoint (eptdev) devices in 2 separate files:

- Rename and export the functions in rpmsg_char.h.

- Suppress the dependency with the rpmsg_ctrldev struct in the
  rpmsg_chrdev_create_eptdev function.

- The rpmsg class is provided as parameter in rpmsg_chrdev_create_eptdev,
  because the class is associated to the control part.

Suggested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
---
 drivers/rpmsg/rpmsg_char.c | 19 +++++++++------
 drivers/rpmsg/rpmsg_char.h | 50 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+), 8 deletions(-)
 create mode 100644 drivers/rpmsg/rpmsg_char.h

diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
index 2bebc9b2d163..b9df8dc4365f 100644
--- a/drivers/rpmsg/rpmsg_char.c
+++ b/drivers/rpmsg/rpmsg_char.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
+ * Copyright (C) 2021, STMicroelectronics
  * Copyright (c) 2016, Linaro Ltd.
  * Copyright (c) 2012, Michal Simek <monstr@monstr.eu>
  * Copyright (c) 2012, PetaLogix
@@ -22,6 +23,7 @@
 #include <linux/uaccess.h>
 #include <uapi/linux/rpmsg.h>
 
+#include "rpmsg_char.h"
 #include "rpmsg_internal.h"
 
 #define RPMSG_DEV_MAX	(MINORMASK + 1)
@@ -78,7 +80,7 @@ struct rpmsg_eptdev {
 	wait_queue_head_t readq;
 };
 
-static int rpmsg_eptdev_destroy(struct device *dev, void *data)
+int rpmsg_chrdev_destroy_eptdev(struct device *dev, void *data)
 {
 	struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);
 
@@ -97,6 +99,7 @@ static int rpmsg_eptdev_destroy(struct device *dev, void *data)
 
 	return 0;
 }
+EXPORT_SYMBOL(rpmsg_chrdev_destroy_eptdev);
 
 static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len,
 			void *priv, u32 addr)
@@ -280,7 +283,7 @@ static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
 	if (cmd != RPMSG_DESTROY_EPT_IOCTL)
 		return -EINVAL;
 
-	return rpmsg_eptdev_destroy(&eptdev->dev, NULL);
+	return rpmsg_chrdev_destroy_eptdev(&eptdev->dev, NULL);
 }
 
 static const struct file_operations rpmsg_eptdev_fops = {
@@ -339,10 +342,9 @@ static void rpmsg_eptdev_release_device(struct device *dev)
 	kfree(eptdev);
 }
 
-static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev,
-			       struct rpmsg_channel_info chinfo)
+int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent,
+			       struct rpmsg_channel_info chinfo, struct class *rpmsg_class)
 {
-	struct rpmsg_device *rpdev = ctrldev->rpdev;
 	struct rpmsg_eptdev *eptdev;
 	struct device *dev;
 	int ret;
@@ -362,7 +364,7 @@ static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev,
 
 	device_initialize(dev);
 	dev->class = rpmsg_class;
-	dev->parent = &ctrldev->dev;
+	dev->parent = parent;
 	dev->groups = rpmsg_eptdev_groups;
 	dev_set_drvdata(dev, eptdev);
 
@@ -405,6 +407,7 @@ static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev,
 
 	return ret;
 }
+EXPORT_SYMBOL(rpmsg_chrdev_create_eptdev);
 
 static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp)
 {
@@ -444,7 +447,7 @@ static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
 	chinfo.src = eptinfo.src;
 	chinfo.dst = eptinfo.dst;
 
-	return rpmsg_eptdev_create(ctrldev, chinfo);
+	return rpmsg_chrdev_create_eptdev(ctrldev->rpdev, &ctrldev->dev, chinfo, rpmsg_class);
 };
 
 static const struct file_operations rpmsg_ctrldev_fops = {
@@ -530,7 +533,7 @@ static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
 	int ret;
 
 	/* Destroy all endpoints */
-	ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_eptdev_destroy);
+	ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_chrdev_destroy_eptdev);
 	if (ret)
 		dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret);
 
diff --git a/drivers/rpmsg/rpmsg_char.h b/drivers/rpmsg/rpmsg_char.h
new file mode 100644
index 000000000000..379d2ae2bee8
--- /dev/null
+++ b/drivers/rpmsg/rpmsg_char.h
@@ -0,0 +1,50 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * Copyright (C) STMicroelectronics 2021.
+ */
+
+#ifndef __RPMSG_CHRDEV_H__
+#define __RPMSG_CHRDEV_H__
+
+#if IS_REACHABLE(CONFIG_RPMSG_CHAR)
+/**
+ * rpmsg_chrdev_create_eptdev() - register char device based on an endpoint
+ * @rpdev:  prepared rpdev to be used for creating endpoints
+ * @parent: parent device
+ * @chinfo: assiated endpoint channel information.
+ *
+ * This function create a new rpmsg char endpoint device to instantiate a new
+ * endpoint based on chinfo information.
+ */
+int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent,
+			       struct rpmsg_channel_info chinfo, struct class *rpmsg_class);
+
+/**
+ * rpmsg_chrdev_destroy_eptdev() - destroy created char device endpoint.
+ * @data: private data associated to the endpoint device
+ *
+ * This function destroys a rpmsg char endpoint device created by the RPMSG_DESTROY_EPT_IOCTL
+ * control.
+ */
+int rpmsg_chrdev_destroy_eptdev(struct device *dev, void *data);
+
+#else  /*IS_REACHABLE(CONFIG_RPMSG_CHAR) */
+
+static inline int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent,
+					     struct rpmsg_channel_info chinfo,
+					     struct class *rpmsg_class)
+{
+	return -EINVAL;
+}
+
+static inline int rpmsg_chrdev_destroy_eptdev(struct device *dev, void *data)
+{
+	/* This shouldn't be possible */
+	WARN_ON(1);
+
+	return 0;
+}
+
+#endif /*IS_REACHABLE(CONFIG_RPMSG_CHAR) */
+
+#endif /*__RPMSG_CHRDEV_H__ */
-- 
2.17.1

[PATCH v2 2/7] rpmsg: Move the rpmsg control device from rpmsg_char to rpmsg_ctrl

[Arnaud Pouliquen]

Create the rpmsg_ctrl.c module and move the code related to the
rpmsg_ctrldev device in this new module.

Add the dependency between rpmsg_char and rpmsg_ctrl in the
kconfig file.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
---
update from v1:
- keep "rpmsg_chrdev" driver name in rpmsg_ctrl, driver will be renamed
  in next path that renames the rpmsg_chrdev_create_eptdev.
- rename the chardev regions
- move RPMSG_DEV_MAX to rpmsg_char.h
---
 drivers/rpmsg/Kconfig      |   9 ++
 drivers/rpmsg/Makefile     |   1 +
 drivers/rpmsg/rpmsg_char.c | 181 +----------------------------
 drivers/rpmsg/rpmsg_char.h |   2 +
 drivers/rpmsg/rpmsg_ctrl.c | 231 +++++++++++++++++++++++++++++++++++++
 5 files changed, 245 insertions(+), 179 deletions(-)
 create mode 100644 drivers/rpmsg/rpmsg_ctrl.c

diff --git a/drivers/rpmsg/Kconfig b/drivers/rpmsg/Kconfig
index 0b4407abdf13..d822ec9ec692 100644
--- a/drivers/rpmsg/Kconfig
+++ b/drivers/rpmsg/Kconfig
@@ -10,11 +10,20 @@ config RPMSG_CHAR
 	tristate "RPMSG device interface"
 	depends on RPMSG
 	depends on NET
+	select RPMSG_CTRL
 	help
 	  Say Y here to export rpmsg endpoints as device files, usually found
 	  in /dev. They make it possible for user-space programs to send and
 	  receive rpmsg packets.
 
+config RPMSG_CTRL
+	tristate "RPMSG control interface"
+	depends on RPMSG
+	help
+	  Say Y here to enable the support of the /dev/rpmsg_ctrlX API. This API
+	  allows user-space programs to create endpoints with specific service name,
+	  source and destination addresses.
+
 config RPMSG_NS
 	tristate "RPMSG name service announcement"
 	depends on RPMSG
diff --git a/drivers/rpmsg/Makefile b/drivers/rpmsg/Makefile
index 8d452656f0ee..58e3b382e316 100644
--- a/drivers/rpmsg/Makefile
+++ b/drivers/rpmsg/Makefile
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_RPMSG)		+= rpmsg_core.o
 obj-$(CONFIG_RPMSG_CHAR)	+= rpmsg_char.o
+obj-$(CONFIG_RPMSG_CTRL)	+= rpmsg_ctrl.o
 obj-$(CONFIG_RPMSG_NS)		+= rpmsg_ns.o
 obj-$(CONFIG_RPMSG_MTK_SCP)	+= mtk_rpmsg.o
 qcom_glink-objs			:= qcom_glink_native.o qcom_glink_ssr.o
diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
index b9df8dc4365f..21ef9d9eccd7 100644
--- a/drivers/rpmsg/rpmsg_char.c
+++ b/drivers/rpmsg/rpmsg_char.c
@@ -26,33 +26,14 @@
 #include "rpmsg_char.h"
 #include "rpmsg_internal.h"
 
-#define RPMSG_DEV_MAX	(MINORMASK + 1)
-
 static dev_t rpmsg_major;
-static struct class *rpmsg_class;
 
-static DEFINE_IDA(rpmsg_ctrl_ida);
 static DEFINE_IDA(rpmsg_ept_ida);
 static DEFINE_IDA(rpmsg_minor_ida);
 
 #define dev_to_eptdev(dev) container_of(dev, struct rpmsg_eptdev, dev)
 #define cdev_to_eptdev(i_cdev) container_of(i_cdev, struct rpmsg_eptdev, cdev)
 
-#define dev_to_ctrldev(dev) container_of(dev, struct rpmsg_ctrldev, dev)
-#define cdev_to_ctrldev(i_cdev) container_of(i_cdev, struct rpmsg_ctrldev, cdev)
-
-/**
- * struct rpmsg_ctrldev - control device for instantiating endpoint devices
- * @rpdev:	underlaying rpmsg device
- * @cdev:	cdev for the ctrl device
- * @dev:	device for the ctrl device
- */
-struct rpmsg_ctrldev {
-	struct rpmsg_device *rpdev;
-	struct cdev cdev;
-	struct device dev;
-};
-
 /**
  * struct rpmsg_eptdev - endpoint device context
  * @dev:	endpoint device
@@ -409,169 +390,13 @@ int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent
 }
 EXPORT_SYMBOL(rpmsg_chrdev_create_eptdev);
 
-static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp)
-{
-	struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);
-
-	get_device(&ctrldev->dev);
-	filp->private_data = ctrldev;
-
-	return 0;
-}
-
-static int rpmsg_ctrldev_release(struct inode *inode, struct file *filp)
-{
-	struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);
-
-	put_device(&ctrldev->dev);
-
-	return 0;
-}
-
-static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
-				unsigned long arg)
-{
-	struct rpmsg_ctrldev *ctrldev = fp->private_data;
-	void __user *argp = (void __user *)arg;
-	struct rpmsg_endpoint_info eptinfo;
-	struct rpmsg_channel_info chinfo;
-
-	if (cmd != RPMSG_CREATE_EPT_IOCTL)
-		return -EINVAL;
-
-	if (copy_from_user(&eptinfo, argp, sizeof(eptinfo)))
-		return -EFAULT;
-
-	memcpy(chinfo.name, eptinfo.name, RPMSG_NAME_SIZE);
-	chinfo.name[RPMSG_NAME_SIZE-1] = '\0';
-	chinfo.src = eptinfo.src;
-	chinfo.dst = eptinfo.dst;
-
-	return rpmsg_chrdev_create_eptdev(ctrldev->rpdev, &ctrldev->dev, chinfo, rpmsg_class);
-};
-
-static const struct file_operations rpmsg_ctrldev_fops = {
-	.owner = THIS_MODULE,
-	.open = rpmsg_ctrldev_open,
-	.release = rpmsg_ctrldev_release,
-	.unlocked_ioctl = rpmsg_ctrldev_ioctl,
-	.compat_ioctl = compat_ptr_ioctl,
-};
-
-static void rpmsg_ctrldev_release_device(struct device *dev)
-{
-	struct rpmsg_ctrldev *ctrldev = dev_to_ctrldev(dev);
-
-	ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
-	ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
-	cdev_del(&ctrldev->cdev);
-	kfree(ctrldev);
-}
-
-static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev)
-{
-	struct rpmsg_ctrldev *ctrldev;
-	struct device *dev;
-	int ret;
-
-	ctrldev = kzalloc(sizeof(*ctrldev), GFP_KERNEL);
-	if (!ctrldev)
-		return -ENOMEM;
-
-	ctrldev->rpdev = rpdev;
-
-	dev = &ctrldev->dev;
-	device_initialize(dev);
-	dev->parent = &rpdev->dev;
-	dev->class = rpmsg_class;
-
-	cdev_init(&ctrldev->cdev, &rpmsg_ctrldev_fops);
-	ctrldev->cdev.owner = THIS_MODULE;
-
-	ret = ida_simple_get(&rpmsg_minor_ida, 0, RPMSG_DEV_MAX, GFP_KERNEL);
-	if (ret < 0)
-		goto free_ctrldev;
-	dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
-
-	ret = ida_simple_get(&rpmsg_ctrl_ida, 0, 0, GFP_KERNEL);
-	if (ret < 0)
-		goto free_minor_ida;
-	dev->id = ret;
-	dev_set_name(&ctrldev->dev, "rpmsg_ctrl%d", ret);
-
-	ret = cdev_add(&ctrldev->cdev, dev->devt, 1);
-	if (ret)
-		goto free_ctrl_ida;
-
-	/* We can now rely on the release function for cleanup */
-	dev->release = rpmsg_ctrldev_release_device;
-
-	ret = device_add(dev);
-	if (ret) {
-		dev_err(&rpdev->dev, "device_add failed: %d\n", ret);
-		put_device(dev);
-	}
-
-	dev_set_drvdata(&rpdev->dev, ctrldev);
-
-	return ret;
-
-free_ctrl_ida:
-	ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
-free_minor_ida:
-	ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
-free_ctrldev:
-	put_device(dev);
-	kfree(ctrldev);
-
-	return ret;
-}
-
-static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
-{
-	struct rpmsg_ctrldev *ctrldev = dev_get_drvdata(&rpdev->dev);
-	int ret;
-
-	/* Destroy all endpoints */
-	ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_chrdev_destroy_eptdev);
-	if (ret)
-		dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret);
-
-	device_del(&ctrldev->dev);
-	put_device(&ctrldev->dev);
-}
-
-static struct rpmsg_driver rpmsg_chrdev_driver = {
-	.probe = rpmsg_chrdev_probe,
-	.remove = rpmsg_chrdev_remove,
-	.drv = {
-		.name = "rpmsg_chrdev",
-	},
-};
-
 static int rpmsg_chrdev_init(void)
 {
 	int ret;
 
-	ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg");
-	if (ret < 0) {
+	ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg_char");
+	if (ret < 0)
 		pr_err("rpmsg: failed to allocate char dev region\n");
-		return ret;
-	}
-
-	rpmsg_class = class_create(THIS_MODULE, "rpmsg");
-	if (IS_ERR(rpmsg_class)) {
-		pr_err("failed to create rpmsg class\n");
-		unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
-		return PTR_ERR(rpmsg_class);
-	}
-
-	ret = register_rpmsg_driver(&rpmsg_chrdev_driver);
-	if (ret < 0) {
-		pr_err("rpmsgchr: failed to register rpmsg driver\n");
-		class_destroy(rpmsg_class);
-		unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
-	}
 
 	return ret;
 }
@@ -579,8 +404,6 @@ postcore_initcall(rpmsg_chrdev_init);
 
 static void rpmsg_chrdev_exit(void)
 {
-	unregister_rpmsg_driver(&rpmsg_chrdev_driver);
-	class_destroy(rpmsg_class);
 	unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
 }
 module_exit(rpmsg_chrdev_exit);
diff --git a/drivers/rpmsg/rpmsg_char.h b/drivers/rpmsg/rpmsg_char.h
index 379d2ae2bee8..f20a215073c3 100644
--- a/drivers/rpmsg/rpmsg_char.h
+++ b/drivers/rpmsg/rpmsg_char.h
@@ -6,6 +6,8 @@
 #ifndef __RPMSG_CHRDEV_H__
 #define __RPMSG_CHRDEV_H__
 
+#define RPMSG_DEV_MAX	(MINORMASK + 1)
+
 #if IS_REACHABLE(CONFIG_RPMSG_CHAR)
 /**
  * rpmsg_chrdev_create_eptdev() - register char device based on an endpoint
diff --git a/drivers/rpmsg/rpmsg_ctrl.c b/drivers/rpmsg/rpmsg_ctrl.c
new file mode 100644
index 000000000000..a5bb9ed97f32
--- /dev/null
+++ b/drivers/rpmsg/rpmsg_ctrl.c
@@ -0,0 +1,231 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2021, STMicroelectronics
+ * Copyright (c) 2016, Linaro Ltd.
+ * Copyright (c) 2012, Michal Simek <monstr@monstr.eu>
+ * Copyright (c) 2012, PetaLogix
+ * Copyright (c) 2011, Texas Instruments, Inc.
+ * Copyright (c) 2011, Google, Inc.
+ *
+ * Based on rpmsg performance statistics driver by Michal Simek, which in turn
+ * was based on TI & Google OMX rpmsg driver.
+ */
+#include <linux/cdev.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/idr.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/rpmsg.h>
+#include <linux/slab.h>
+#include <uapi/linux/rpmsg.h>
+
+#include "rpmsg_char.h"
+#include "rpmsg_internal.h"
+
+static dev_t rpmsg_major;
+struct class *rpmsg_class;
+
+static DEFINE_IDA(rpmsg_ctrl_ida);
+static DEFINE_IDA(rpmsg_minor_ida);
+
+#define dev_to_ctrldev(dev) container_of(dev, struct rpmsg_ctrldev, dev)
+#define cdev_to_ctrldev(i_cdev) container_of(i_cdev, struct rpmsg_ctrldev, cdev)
+
+/**
+ * struct rpmsg_ctrldev - control device for instantiating endpoint devices
+ * @rpdev:	underlaying rpmsg device
+ * @cdev:	cdev for the ctrl device
+ * @dev:	device for the ctrl device
+ */
+struct rpmsg_ctrldev {
+	struct rpmsg_device *rpdev;
+	struct cdev cdev;
+	struct device dev;
+};
+
+static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp)
+{
+	struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);
+
+	get_device(&ctrldev->dev);
+	filp->private_data = ctrldev;
+
+	return 0;
+}
+
+static int rpmsg_ctrldev_release(struct inode *inode, struct file *filp)
+{
+	struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);
+
+	put_device(&ctrldev->dev);
+
+	return 0;
+}
+
+static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
+				unsigned long arg)
+{
+	struct rpmsg_ctrldev *ctrldev = fp->private_data;
+	void __user *argp = (void __user *)arg;
+	struct rpmsg_endpoint_info eptinfo;
+	struct rpmsg_channel_info chinfo;
+
+	if (cmd != RPMSG_CREATE_EPT_IOCTL)
+		return -EINVAL;
+
+	if (copy_from_user(&eptinfo, argp, sizeof(eptinfo)))
+		return -EFAULT;
+
+	memcpy(chinfo.name, eptinfo.name, RPMSG_NAME_SIZE);
+	chinfo.name[RPMSG_NAME_SIZE - 1] = '\0';
+	chinfo.src = eptinfo.src;
+	chinfo.dst = eptinfo.dst;
+
+	return rpmsg_chrdev_create_eptdev(ctrldev->rpdev, &ctrldev->dev, chinfo, rpmsg_class);
+};
+
+static const struct file_operations rpmsg_ctrldev_fops = {
+	.owner = THIS_MODULE,
+	.open = rpmsg_ctrldev_open,
+	.release = rpmsg_ctrldev_release,
+	.unlocked_ioctl = rpmsg_ctrldev_ioctl,
+	.compat_ioctl = compat_ptr_ioctl,
+};
+
+static void rpmsg_ctrldev_release_device(struct device *dev)
+{
+	struct rpmsg_ctrldev *ctrldev = dev_to_ctrldev(dev);
+
+	ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
+	ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
+	cdev_del(&ctrldev->cdev);
+	kfree(ctrldev);
+}
+
+static int rpmsg_ctrldev_probe(struct rpmsg_device *rpdev)
+{
+	struct rpmsg_ctrldev *ctrldev;
+	struct device *dev;
+	int ret;
+
+	ctrldev = kzalloc(sizeof(*ctrldev), GFP_KERNEL);
+	if (!ctrldev)
+		return -ENOMEM;
+
+	ctrldev->rpdev = rpdev;
+
+	dev = &ctrldev->dev;
+	device_initialize(dev);
+	dev->parent = &rpdev->dev;
+	dev->class = rpmsg_class;
+
+	cdev_init(&ctrldev->cdev, &rpmsg_ctrldev_fops);
+	ctrldev->cdev.owner = THIS_MODULE;
+
+	ret = ida_simple_get(&rpmsg_minor_ida, 0, RPMSG_DEV_MAX, GFP_KERNEL);
+	if (ret < 0)
+		goto free_ctrldev;
+	dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
+
+	ret = ida_simple_get(&rpmsg_ctrl_ida, 0, 0, GFP_KERNEL);
+	if (ret < 0)
+		goto free_minor_ida;
+	dev->id = ret;
+	dev_set_name(&ctrldev->dev, "rpmsg_ctrl%d", ret);
+
+	ret = cdev_add(&ctrldev->cdev, dev->devt, 1);
+	if (ret)
+		goto free_ctrl_ida;
+
+	/* We can now rely on the release function for cleanup */
+	dev->release = rpmsg_ctrldev_release_device;
+
+	ret = device_add(dev);
+	if (ret) {
+		dev_err(&rpdev->dev, "device_add failed: %d\n", ret);
+		put_device(dev);
+	}
+
+	dev_set_drvdata(&rpdev->dev, ctrldev);
+
+	return ret;
+
+free_ctrl_ida:
+	ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
+free_minor_ida:
+	ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
+free_ctrldev:
+	put_device(dev);
+	kfree(ctrldev);
+
+	return ret;
+}
+
+static void rpmsg_ctrldev_remove(struct rpmsg_device *rpdev)
+{
+	struct rpmsg_ctrldev *ctrldev = dev_get_drvdata(&rpdev->dev);
+	int ret;
+
+	/* Destroy all endpoints */
+	ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_chrdev_destroy_eptdev);
+	if (ret)
+		dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret);
+
+	device_del(&ctrldev->dev);
+	put_device(&ctrldev->dev);
+}
+
+static struct rpmsg_driver rpmsg_ctrldev_driver = {
+	.probe = rpmsg_ctrldev_probe,
+	.remove = rpmsg_ctrldev_remove,
+	.drv = {
+		.name = "rpmsg_chrdev",
+	},
+};
+
+static int rpmsg_ctrldev_init(void)
+{
+	int ret;
+
+	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");
+		return ret;
+	}
+
+	rpmsg_class = class_create(THIS_MODULE, "rpmsg");
+	if (IS_ERR(rpmsg_class)) {
+		pr_err("failed to create rpmsg class\n");
+		ret = PTR_ERR(rpmsg_class);
+		goto free_region;
+	}
+
+	ret = register_rpmsg_driver(&rpmsg_ctrldev_driver);
+	if (ret < 0) {
+		pr_err("rpmsg ctrl: failed to register rpmsg driver\n");
+		goto free_class;
+	}
+
+	return 0;
+
+free_class:
+	class_destroy(rpmsg_class);
+free_region:
+	unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
+
+	return ret;
+}
+postcore_initcall(rpmsg_ctrldev_init);
+
+static void rpmsg_ctrldev_exit(void)
+{
+	unregister_rpmsg_driver(&rpmsg_ctrldev_driver);
+	class_destroy(rpmsg_class);
+	unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
+}
+module_exit(rpmsg_ctrldev_exit);
+
+MODULE_DESCRIPTION("rpmsg control interface");
+MODULE_ALIAS("rpmsg:" KBUILD_MODNAME);
+MODULE_LICENSE("GPL v2");
-- 
2.17.1

[PATCH v2 3/7] rpmsg: Update rpmsg_chrdev_register_device function

[Arnaud Pouliquen]

The rpmsg_chrdev driver has been replaced by the rpmsg_ctrl driver
for the /dev/rpmsg_ctrlX devices management. The reference for the
driver override is now the rpmsg_ctrl.

Update the rpmsg_chrdev_register_device function to reflect the update,
and rename the function to use the rpmsg_ctrldev prefix.

The platform drivers are updated accordingly.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>

---
update from v1
- move the rename of the rpmsg_ctrl driver from previous patch to
  this one.
---
 drivers/rpmsg/qcom_glink_native.c | 2 +-
 drivers/rpmsg/qcom_smd.c          | 2 +-
 drivers/rpmsg/rpmsg_ctrl.c        | 2 +-
 drivers/rpmsg/rpmsg_internal.h    | 8 ++++----
 drivers/rpmsg/virtio_rpmsg_bus.c  | 2 +-
 5 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
index 05533c71b10e..7d7e809800ec 100644
--- a/drivers/rpmsg/qcom_glink_native.c
+++ b/drivers/rpmsg/qcom_glink_native.c
@@ -1642,7 +1642,7 @@ static int qcom_glink_create_chrdev(struct qcom_glink *glink)
 	rpdev->dev.parent = glink->dev;
 	rpdev->dev.release = qcom_glink_device_release;
 
-	return rpmsg_chrdev_register_device(rpdev);
+	return rpmsg_ctrldev_register_device(rpdev);
 }
 
 struct qcom_glink *qcom_glink_native_probe(struct device *dev,
diff --git a/drivers/rpmsg/qcom_smd.c b/drivers/rpmsg/qcom_smd.c
index 8da1b5cb31b3..d223e438d17c 100644
--- a/drivers/rpmsg/qcom_smd.c
+++ b/drivers/rpmsg/qcom_smd.c
@@ -1113,7 +1113,7 @@ static int qcom_smd_create_chrdev(struct qcom_smd_edge *edge)
 	qsdev->rpdev.dev.parent = &edge->dev;
 	qsdev->rpdev.dev.release = qcom_smd_release_device;
 
-	return rpmsg_chrdev_register_device(&qsdev->rpdev);
+	return rpmsg_ctrldev_register_device(&qsdev->rpdev);
 }
 
 /*
diff --git a/drivers/rpmsg/rpmsg_ctrl.c b/drivers/rpmsg/rpmsg_ctrl.c
index a5bb9ed97f32..059c228d0045 100644
--- a/drivers/rpmsg/rpmsg_ctrl.c
+++ b/drivers/rpmsg/rpmsg_ctrl.c
@@ -180,7 +180,7 @@ static struct rpmsg_driver rpmsg_ctrldev_driver = {
 	.probe = rpmsg_ctrldev_probe,
 	.remove = rpmsg_ctrldev_remove,
 	.drv = {
-		.name = "rpmsg_chrdev",
+		.name = "rpmsg_ctrl",
 	},
 };
 
diff --git a/drivers/rpmsg/rpmsg_internal.h b/drivers/rpmsg/rpmsg_internal.h
index a76c344253bf..8c500a8f29aa 100644
--- a/drivers/rpmsg/rpmsg_internal.h
+++ b/drivers/rpmsg/rpmsg_internal.h
@@ -82,16 +82,16 @@ struct rpmsg_device *rpmsg_create_channel(struct rpmsg_device *rpdev,
 int rpmsg_release_channel(struct rpmsg_device *rpdev,
 			  struct rpmsg_channel_info *chinfo);
 /**
- * rpmsg_chrdev_register_device() - register chrdev device based on rpdev
+ * rpmsg_ctrl_register_device() - register a char device for control based on rpdev
  * @rpdev:	prepared rpdev to be used for creating endpoints
  *
  * This function wraps rpmsg_register_device() preparing the rpdev for use as
  * basis for the rpmsg chrdev.
  */
-static inline int rpmsg_chrdev_register_device(struct rpmsg_device *rpdev)
+static inline int rpmsg_ctrldev_register_device(struct rpmsg_device *rpdev)
 {
-	strcpy(rpdev->id.name, "rpmsg_chrdev");
-	rpdev->driver_override = "rpmsg_chrdev";
+	strcpy(rpdev->id.name, "rpmsg_ctrl");
+	rpdev->driver_override = "rpmsg_ctrl";
 
 	return rpmsg_register_device(rpdev);
 }
diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c
index 8e49a3bacfc7..e42234a3e2ab 100644
--- a/drivers/rpmsg/virtio_rpmsg_bus.c
+++ b/drivers/rpmsg/virtio_rpmsg_bus.c
@@ -840,7 +840,7 @@ static struct rpmsg_device *rpmsg_virtio_add_ctrl_dev(struct virtio_device *vdev
 	rpdev_ctrl->dev.release = virtio_rpmsg_release_device;
 	rpdev_ctrl->little_endian = virtio_is_little_endian(vrp->vdev);
 
-	err = rpmsg_chrdev_register_device(rpdev_ctrl);
+	err = rpmsg_ctrldev_register_device(rpdev_ctrl);
 	if (err) {
 		kfree(vch);
 		return ERR_PTR(err);
-- 
2.17.1

[PATCH v2 4/7] rpmsg: char: Introduce __rpmsg_chrdev_create_eptdev function

[Arnaud Pouliquen]

Introduce the __rpmsg_chrdev_create_eptdev internal function that returns
the rpmsg_eptdev context structure.

This patch prepares the introduction of a rpmsg channel device for the
char device. The rpmsg device will need a reference to the context.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>

---
update from V1
- fix __rpmsg_chrdev_create_eptdev function header indentation.

---
 drivers/rpmsg/rpmsg_char.c | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
index 21ef9d9eccd7..a64249d83172 100644
--- a/drivers/rpmsg/rpmsg_char.c
+++ b/drivers/rpmsg/rpmsg_char.c
@@ -323,8 +323,9 @@ static void rpmsg_eptdev_release_device(struct device *dev)
 	kfree(eptdev);
 }
 
-int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent,
-			       struct rpmsg_channel_info chinfo, struct class *rpmsg_class)
+static struct rpmsg_eptdev *
+__rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent,
+			     struct rpmsg_channel_info chinfo, struct class *rpmsg_class)
 {
 	struct rpmsg_eptdev *eptdev;
 	struct device *dev;
@@ -332,7 +333,7 @@ int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent
 
 	eptdev = kzalloc(sizeof(*eptdev), GFP_KERNEL);
 	if (!eptdev)
-		return -ENOMEM;
+		return ERR_PTR(-ENOMEM);
 
 	dev = &eptdev->dev;
 	eptdev->rpdev = rpdev;
@@ -376,7 +377,7 @@ int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent
 		put_device(dev);
 	}
 
-	return ret;
+	return eptdev;
 
 free_ept_ida:
 	ida_simple_remove(&rpmsg_ept_ida, dev->id);
@@ -386,7 +387,19 @@ int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent
 	put_device(dev);
 	kfree(eptdev);
 
-	return ret;
+	return ERR_PTR(ret);
+}
+
+int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent,
+			       struct rpmsg_channel_info chinfo,  struct class *rpmsg_class)
+{
+	struct rpmsg_eptdev *eptdev;
+
+	eptdev = __rpmsg_chrdev_create_eptdev(rpdev, parent, chinfo, rpmsg_class);
+	if (IS_ERR(eptdev))
+		return PTR_ERR(eptdev);
+
+	return 0;
 }
 EXPORT_SYMBOL(rpmsg_chrdev_create_eptdev);
 
-- 
2.17.1

[PATCH v2 5/7] rpmsg: char: Introduce a rpmsg driver for the rpmsg char device

[Arnaud Pouliquen]

A rpmsg char device allows to probe the endpoint device on a remote name
service announcement.

With this patch the /dev/rpmsgX interface is created either by a user
application or by the remote firmware.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>

---
update from V1:
 - add missing unregister_rpmsg_driver call on module exit.

---
 drivers/rpmsg/rpmsg_char.c | 59 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 58 insertions(+), 1 deletion(-)

diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
index a64249d83172..4606787b7011 100644
--- a/drivers/rpmsg/rpmsg_char.c
+++ b/drivers/rpmsg/rpmsg_char.c
@@ -26,6 +26,8 @@
 #include "rpmsg_char.h"
 #include "rpmsg_internal.h"
 
+#define RPMSG_CHAR_DEVNAME "rpmsg-raw"
+
 static dev_t rpmsg_major;
 
 static DEFINE_IDA(rpmsg_ept_ida);
@@ -403,13 +405,67 @@ int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent
 }
 EXPORT_SYMBOL(rpmsg_chrdev_create_eptdev);
 
+static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev)
+{
+	struct rpmsg_channel_info chinfo;
+	struct rpmsg_eptdev *eptdev;
+
+	if (!rpdev->ept)
+		return -EINVAL;
+
+	memcpy(chinfo.name, RPMSG_CHAR_DEVNAME, sizeof(RPMSG_CHAR_DEVNAME));
+	chinfo.src = rpdev->src;
+	chinfo.dst = rpdev->dst;
+
+	eptdev = __rpmsg_chrdev_create_eptdev(rpdev, &rpdev->dev, chinfo, NULL);
+	if (IS_ERR(eptdev))
+		return PTR_ERR(eptdev);
+
+	/* Set the private field of the default endpoint to retrieve context on callback. */
+	rpdev->ept->priv = eptdev;
+
+	return 0;
+}
+
+static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
+{
+	int ret;
+
+	ret = device_for_each_child(&rpdev->dev, NULL, rpmsg_chrdev_destroy_eptdev);
+	if (ret)
+		dev_warn(&rpdev->dev, "failed to destroy endpoints: %d\n", ret);
+}
+
+static struct rpmsg_device_id rpmsg_chrdev_id_table[] = {
+	{ .name	= RPMSG_CHAR_DEVNAME },
+	{ },
+};
+
+static struct rpmsg_driver rpmsg_chrdev_driver = {
+	.probe = rpmsg_chrdev_probe,
+	.remove = rpmsg_chrdev_remove,
+	.id_table = rpmsg_chrdev_id_table,
+	.callback = rpmsg_ept_cb,
+	.drv = {
+		.name = "rpmsg_chrdev",
+	},
+};
+
 static int rpmsg_chrdev_init(void)
 {
 	int ret;
 
 	ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg_char");
-	if (ret < 0)
+	if (ret < 0) {
 		pr_err("rpmsg: failed to allocate char dev region\n");
+		return ret;
+	}
+
+	ret = register_rpmsg_driver(&rpmsg_chrdev_driver);
+	if (ret < 0) {
+		pr_err("rpmsg: failed to register rpmsg raw driver\n");
+		unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
+	}
 
 	return ret;
 }
@@ -417,6 +473,7 @@ 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);
-- 
2.17.1

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

[Arnaud Pouliquen]

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@foss.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

[PATCH v2 7/7] rpmsg: char: Return error if user tries to destroy a default endpoint.

[Arnaud Pouliquen]

Using the RPMSG_DESTROY_EPT_IOCTL control, user application can
destroy an endpoint. This patch prevents to destroy a default endpoint
associated to a channel.

This update is needed to manage the "rpmsg-raw" channel. In this
case a default endpoint is used and destroying it without the
channel does not make sense.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
---
 drivers/rpmsg/rpmsg_char.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
index fa59abfa8878..d4316bb904f2 100644
--- a/drivers/rpmsg/rpmsg_char.c
+++ b/drivers/rpmsg/rpmsg_char.c
@@ -280,6 +280,10 @@ 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->rpdev || eptdev->ept == eptdev->rpdev->ept)
+		return -EPERM;
+
 	return rpmsg_chrdev_destroy_eptdev(&eptdev->dev, NULL);
 }
 
-- 
2.17.1

Re: [PATCH v2 5/7] rpmsg: char: Introduce a rpmsg driver for the rpmsg char device

[Mathieu Poirier]

Good day Arnaud,

On Tue, Apr 13, 2021 at 03:44:56PM +0200, Arnaud Pouliquen wrote:
> A rpmsg char device allows to probe the endpoint device on a remote name
> service announcement.
> 
> With this patch the /dev/rpmsgX interface is created either by a user
> application or by the remote firmware.
> 
> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
> 
> ---
> update from V1:
>  - add missing unregister_rpmsg_driver call on module exit.
> 
> ---
>  drivers/rpmsg/rpmsg_char.c | 59 +++++++++++++++++++++++++++++++++++++-
>  1 file changed, 58 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
> index a64249d83172..4606787b7011 100644
> --- a/drivers/rpmsg/rpmsg_char.c
> +++ b/drivers/rpmsg/rpmsg_char.c
> @@ -26,6 +26,8 @@
>  #include "rpmsg_char.h"
>  #include "rpmsg_internal.h"
>  
> +#define RPMSG_CHAR_DEVNAME "rpmsg-raw"
> +

Why not simply call it rpmsg-char?

>  static dev_t rpmsg_major;
>  
>  static DEFINE_IDA(rpmsg_ept_ida);
> @@ -403,13 +405,67 @@ int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent
>  }
>  EXPORT_SYMBOL(rpmsg_chrdev_create_eptdev);
>  
> +static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev)
> +{
> +	struct rpmsg_channel_info chinfo;
> +	struct rpmsg_eptdev *eptdev;
> +
> +	if (!rpdev->ept)
> +		return -EINVAL;
> +
> +	memcpy(chinfo.name, RPMSG_CHAR_DEVNAME, sizeof(RPMSG_CHAR_DEVNAME));
> +	chinfo.src = rpdev->src;
> +	chinfo.dst = rpdev->dst;
> +
> +	eptdev = __rpmsg_chrdev_create_eptdev(rpdev, &rpdev->dev, chinfo, NULL);
> +	if (IS_ERR(eptdev))
> +		return PTR_ERR(eptdev);
> +
> +	/* Set the private field of the default endpoint to retrieve context on callback. */
> +	rpdev->ept->priv = eptdev;

This is already done in rpmsg_create_ept() when rpmsg_eptdev_open() is called.

> +
> +	return 0;
> +}
> +
> +static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
> +{
> +	int ret;
> +
> +	ret = device_for_each_child(&rpdev->dev, NULL, rpmsg_chrdev_destroy_eptdev);
> +	if (ret)
> +		dev_warn(&rpdev->dev, "failed to destroy endpoints: %d\n", ret);
> +}
> +
> +static struct rpmsg_device_id rpmsg_chrdev_id_table[] = {
> +	{ .name	= RPMSG_CHAR_DEVNAME },
> +	{ },
> +};
> +
> +static struct rpmsg_driver rpmsg_chrdev_driver = {
> +	.probe = rpmsg_chrdev_probe,
> +	.remove = rpmsg_chrdev_remove,
> +	.id_table = rpmsg_chrdev_id_table,
> +	.callback = rpmsg_ept_cb,

Not sure why we need a callback associated to this driver when
rpmsg_eptdev_open() already creates and rpmsg_endpoint.  To me the only thing
having a callback provides is the association between the rpmsg_device and the
rpmsg_endpoint[1] that happens in rpmsg_dev_probe().  The QC folks already do
this association in their platform code[2].  Since this is not done in
__rpmsg_create_ept() a check for rpdev->ept == NULL could be done in
rpmsg_eptdev_open() and do the assignment there. 

[1]. https://elixir.bootlin.com/linux/v5.12-rc6/source/drivers/rpmsg/rpmsg_core.c#L513  
[2]. https://elixir.bootlin.com/linux/v5.12-rc6/source/drivers/rpmsg/qcom_glink_native.c#L1623

> +	.drv = {
> +		.name = "rpmsg_chrdev",
> +	},
> +};
> +
>  static int rpmsg_chrdev_init(void)
>  {
>  	int ret;
>  
>  	ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg_char");
> -	if (ret < 0)
> +	if (ret < 0) {
>  		pr_err("rpmsg: failed to allocate char dev region\n");
> +		return ret;
> +	}
> +
> +	ret = register_rpmsg_driver(&rpmsg_chrdev_driver);
> +	if (ret < 0) {
> +		pr_err("rpmsg: failed to register rpmsg raw driver\n");
> +		unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
> +	}
>  
>  	return ret;
>  }
> @@ -417,6 +473,7 @@ 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);
> -- 
> 2.17.1
> 

Re: [PATCH v2 4/7] rpmsg: char: Introduce __rpmsg_chrdev_create_eptdev function

[Mathieu Poirier]

On Tue, Apr 13, 2021 at 03:44:55PM +0200, Arnaud Pouliquen wrote:
> Introduce the __rpmsg_chrdev_create_eptdev internal function that returns
> the rpmsg_eptdev context structure.
> 
> This patch prepares the introduction of a rpmsg channel device for the
> char device. The rpmsg device will need a reference to the context.
> 
> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
> 
> ---
> update from V1
> - fix __rpmsg_chrdev_create_eptdev function header indentation.
> 
> ---
>  drivers/rpmsg/rpmsg_char.c | 23 ++++++++++++++++++-----
>  1 file changed, 18 insertions(+), 5 deletions(-)

Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>

> 
> diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
> index 21ef9d9eccd7..a64249d83172 100644
> --- a/drivers/rpmsg/rpmsg_char.c
> +++ b/drivers/rpmsg/rpmsg_char.c
> @@ -323,8 +323,9 @@ static void rpmsg_eptdev_release_device(struct device *dev)
>  	kfree(eptdev);
>  }
>  
> -int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent,
> -			       struct rpmsg_channel_info chinfo, struct class *rpmsg_class)
> +static struct rpmsg_eptdev *
> +__rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent,
> +			     struct rpmsg_channel_info chinfo, struct class *rpmsg_class)
>  {
>  	struct rpmsg_eptdev *eptdev;
>  	struct device *dev;
> @@ -332,7 +333,7 @@ int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent
>  
>  	eptdev = kzalloc(sizeof(*eptdev), GFP_KERNEL);
>  	if (!eptdev)
> -		return -ENOMEM;
> +		return ERR_PTR(-ENOMEM);
>  
>  	dev = &eptdev->dev;
>  	eptdev->rpdev = rpdev;
> @@ -376,7 +377,7 @@ int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent
>  		put_device(dev);
>  	}
>  
> -	return ret;
> +	return eptdev;
>  
>  free_ept_ida:
>  	ida_simple_remove(&rpmsg_ept_ida, dev->id);
> @@ -386,7 +387,19 @@ int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent
>  	put_device(dev);
>  	kfree(eptdev);
>  
> -	return ret;
> +	return ERR_PTR(ret);
> +}
> +
> +int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent,
> +			       struct rpmsg_channel_info chinfo,  struct class *rpmsg_class)
> +{
> +	struct rpmsg_eptdev *eptdev;
> +
> +	eptdev = __rpmsg_chrdev_create_eptdev(rpdev, parent, chinfo, rpmsg_class);
> +	if (IS_ERR(eptdev))
> +		return PTR_ERR(eptdev);
> +
> +	return 0;
>  }
>  EXPORT_SYMBOL(rpmsg_chrdev_create_eptdev);
>  
> -- 
> 2.17.1
> 

Re: [PATCH v2 4/7] rpmsg: char: Introduce __rpmsg_chrdev_create_eptdev function

[Mathieu Poirier]

On Wed, Apr 21, 2021 at 11:43:29AM -0600, Mathieu Poirier wrote:
> On Tue, Apr 13, 2021 at 03:44:55PM +0200, Arnaud Pouliquen wrote:
> > Introduce the __rpmsg_chrdev_create_eptdev internal function that returns
> > the rpmsg_eptdev context structure.
> > 
> > This patch prepares the introduction of a rpmsg channel device for the
> > char device. The rpmsg device will need a reference to the context.
> > 
> > Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
> > 
> > ---
> > update from V1
> > - fix __rpmsg_chrdev_create_eptdev function header indentation.
> > 
> > ---
> >  drivers/rpmsg/rpmsg_char.c | 23 ++++++++++++++++++-----
> >  1 file changed, 18 insertions(+), 5 deletions(-)
> 
> Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
>

Please excuse the brain-bug here - this RB was destined to patch 3/7.  I am not sure
about this patch yet (see comment in 5/7).
 
> > 
> > diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
> > index 21ef9d9eccd7..a64249d83172 100644
> > --- a/drivers/rpmsg/rpmsg_char.c
> > +++ b/drivers/rpmsg/rpmsg_char.c
> > @@ -323,8 +323,9 @@ static void rpmsg_eptdev_release_device(struct device *dev)
> >  	kfree(eptdev);
> >  }
> >  
> > -int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent,
> > -			       struct rpmsg_channel_info chinfo, struct class *rpmsg_class)
> > +static struct rpmsg_eptdev *
> > +__rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent,
> > +			     struct rpmsg_channel_info chinfo, struct class *rpmsg_class)
> >  {
> >  	struct rpmsg_eptdev *eptdev;
> >  	struct device *dev;
> > @@ -332,7 +333,7 @@ int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent
> >  
> >  	eptdev = kzalloc(sizeof(*eptdev), GFP_KERNEL);
> >  	if (!eptdev)
> > -		return -ENOMEM;
> > +		return ERR_PTR(-ENOMEM);
> >  
> >  	dev = &eptdev->dev;
> >  	eptdev->rpdev = rpdev;
> > @@ -376,7 +377,7 @@ int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent
> >  		put_device(dev);
> >  	}
> >  
> > -	return ret;
> > +	return eptdev;
> >  
> >  free_ept_ida:
> >  	ida_simple_remove(&rpmsg_ept_ida, dev->id);
> > @@ -386,7 +387,19 @@ int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent
> >  	put_device(dev);
> >  	kfree(eptdev);
> >  
> > -	return ret;
> > +	return ERR_PTR(ret);
> > +}
> > +
> > +int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent,
> > +			       struct rpmsg_channel_info chinfo,  struct class *rpmsg_class)
> > +{
> > +	struct rpmsg_eptdev *eptdev;
> > +
> > +	eptdev = __rpmsg_chrdev_create_eptdev(rpdev, parent, chinfo, rpmsg_class);
> > +	if (IS_ERR(eptdev))
> > +		return PTR_ERR(eptdev);
> > +
> > +	return 0;
> >  }
> >  EXPORT_SYMBOL(rpmsg_chrdev_create_eptdev);
> >  
> > -- 
> > 2.17.1
> > 

Re: [PATCH v2 1/7] rpmsg: char: Export eptdev create an destroy functions

[Mathieu Poirier]

On Tue, Apr 13, 2021 at 03:44:52PM +0200, Arnaud Pouliquen wrote:
> To prepare the split of the code related to the control (ctrldev)
> and the endpoint (eptdev) devices in 2 separate files:
> 
> - Rename and export the functions in rpmsg_char.h.
> 
> - Suppress the dependency with the rpmsg_ctrldev struct in the
>   rpmsg_chrdev_create_eptdev function.
> 
> - The rpmsg class is provided as parameter in rpmsg_chrdev_create_eptdev,
>   because the class is associated to the control part.
> 
> Suggested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
> ---
>  drivers/rpmsg/rpmsg_char.c | 19 +++++++++------
>  drivers/rpmsg/rpmsg_char.h | 50 ++++++++++++++++++++++++++++++++++++++
>  2 files changed, 61 insertions(+), 8 deletions(-)
>  create mode 100644 drivers/rpmsg/rpmsg_char.h
> 
> diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
> index 2bebc9b2d163..b9df8dc4365f 100644
> --- a/drivers/rpmsg/rpmsg_char.c
> +++ b/drivers/rpmsg/rpmsg_char.c
> @@ -1,5 +1,6 @@
>  // SPDX-License-Identifier: GPL-2.0
>  /*
> + * Copyright (C) 2021, STMicroelectronics
>   * Copyright (c) 2016, Linaro Ltd.
>   * Copyright (c) 2012, Michal Simek <monstr@monstr.eu>
>   * Copyright (c) 2012, PetaLogix
> @@ -22,6 +23,7 @@
>  #include <linux/uaccess.h>
>  #include <uapi/linux/rpmsg.h>
>  
> +#include "rpmsg_char.h"
>  #include "rpmsg_internal.h"
>  
>  #define RPMSG_DEV_MAX	(MINORMASK + 1)
> @@ -78,7 +80,7 @@ struct rpmsg_eptdev {
>  	wait_queue_head_t readq;
>  };
>  
> -static int rpmsg_eptdev_destroy(struct device *dev, void *data)
> +int rpmsg_chrdev_destroy_eptdev(struct device *dev, void *data)

Shouldn't this be rpmsg_chrdev_eptdev_destroy()?  I've been wondering about the
flipping of destroy and eptdev...  The same for rpmsg_chrdev_create_eptdev().

With that:

Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>

>  {
>  	struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);
>  
> @@ -97,6 +99,7 @@ static int rpmsg_eptdev_destroy(struct device *dev, void *data)
>  
>  	return 0;
>  }
> +EXPORT_SYMBOL(rpmsg_chrdev_destroy_eptdev);
>  
>  static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len,
>  			void *priv, u32 addr)
> @@ -280,7 +283,7 @@ static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
>  	if (cmd != RPMSG_DESTROY_EPT_IOCTL)
>  		return -EINVAL;
>  
> -	return rpmsg_eptdev_destroy(&eptdev->dev, NULL);
> +	return rpmsg_chrdev_destroy_eptdev(&eptdev->dev, NULL);
>  }
>  
>  static const struct file_operations rpmsg_eptdev_fops = {
> @@ -339,10 +342,9 @@ static void rpmsg_eptdev_release_device(struct device *dev)
>  	kfree(eptdev);
>  }
>  
> -static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev,
> -			       struct rpmsg_channel_info chinfo)
> +int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent,
> +			       struct rpmsg_channel_info chinfo, struct class *rpmsg_class)
>  {
> -	struct rpmsg_device *rpdev = ctrldev->rpdev;
>  	struct rpmsg_eptdev *eptdev;
>  	struct device *dev;
>  	int ret;
> @@ -362,7 +364,7 @@ static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev,
>  
>  	device_initialize(dev);
>  	dev->class = rpmsg_class;
> -	dev->parent = &ctrldev->dev;
> +	dev->parent = parent;
>  	dev->groups = rpmsg_eptdev_groups;
>  	dev_set_drvdata(dev, eptdev);
>  
> @@ -405,6 +407,7 @@ static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev,
>  
>  	return ret;
>  }
> +EXPORT_SYMBOL(rpmsg_chrdev_create_eptdev);
>  
>  static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp)
>  {
> @@ -444,7 +447,7 @@ static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
>  	chinfo.src = eptinfo.src;
>  	chinfo.dst = eptinfo.dst;
>  
> -	return rpmsg_eptdev_create(ctrldev, chinfo);
> +	return rpmsg_chrdev_create_eptdev(ctrldev->rpdev, &ctrldev->dev, chinfo, rpmsg_class);
>  };
>  
>  static const struct file_operations rpmsg_ctrldev_fops = {
> @@ -530,7 +533,7 @@ static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
>  	int ret;
>  
>  	/* Destroy all endpoints */
> -	ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_eptdev_destroy);
> +	ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_chrdev_destroy_eptdev);
>  	if (ret)
>  		dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret);
>  
> diff --git a/drivers/rpmsg/rpmsg_char.h b/drivers/rpmsg/rpmsg_char.h
> new file mode 100644
> index 000000000000..379d2ae2bee8
> --- /dev/null
> +++ b/drivers/rpmsg/rpmsg_char.h
> @@ -0,0 +1,50 @@
> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> +/*
> + * Copyright (C) STMicroelectronics 2021.
> + */
> +
> +#ifndef __RPMSG_CHRDEV_H__
> +#define __RPMSG_CHRDEV_H__
> +
> +#if IS_REACHABLE(CONFIG_RPMSG_CHAR)
> +/**
> + * rpmsg_chrdev_create_eptdev() - register char device based on an endpoint
> + * @rpdev:  prepared rpdev to be used for creating endpoints
> + * @parent: parent device
> + * @chinfo: assiated endpoint channel information.
> + *
> + * This function create a new rpmsg char endpoint device to instantiate a new
> + * endpoint based on chinfo information.
> + */
> +int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent,
> +			       struct rpmsg_channel_info chinfo, struct class *rpmsg_class);
> +
> +/**
> + * rpmsg_chrdev_destroy_eptdev() - destroy created char device endpoint.
> + * @data: private data associated to the endpoint device
> + *
> + * This function destroys a rpmsg char endpoint device created by the RPMSG_DESTROY_EPT_IOCTL
> + * control.
> + */
> +int rpmsg_chrdev_destroy_eptdev(struct device *dev, void *data);
> +
> +#else  /*IS_REACHABLE(CONFIG_RPMSG_CHAR) */
> +
> +static inline int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent,
> +					     struct rpmsg_channel_info chinfo,
> +					     struct class *rpmsg_class)
> +{
> +	return -EINVAL;
> +}
> +
> +static inline int rpmsg_chrdev_destroy_eptdev(struct device *dev, void *data)
> +{
> +	/* This shouldn't be possible */
> +	WARN_ON(1);
> +
> +	return 0;
> +}
> +
> +#endif /*IS_REACHABLE(CONFIG_RPMSG_CHAR) */
> +
> +#endif /*__RPMSG_CHRDEV_H__ */
> -- 
> 2.17.1
> 

Re: [PATCH v2 2/7] rpmsg: Move the rpmsg control device from rpmsg_char to rpmsg_ctrl

[Mathieu Poirier]

On Tue, Apr 13, 2021 at 03:44:53PM +0200, Arnaud Pouliquen wrote:
> Create the rpmsg_ctrl.c module and move the code related to the
> rpmsg_ctrldev device in this new module.
> 
> Add the dependency between rpmsg_char and rpmsg_ctrl in the
> kconfig file.
> 
> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
> ---
> update from v1:
> - keep "rpmsg_chrdev" driver name in rpmsg_ctrl, driver will be renamed
>   in next path that renames the rpmsg_chrdev_create_eptdev.
> - rename the chardev regions
> - move RPMSG_DEV_MAX to rpmsg_char.h
> ---
>  drivers/rpmsg/Kconfig      |   9 ++
>  drivers/rpmsg/Makefile     |   1 +
>  drivers/rpmsg/rpmsg_char.c | 181 +----------------------------
>  drivers/rpmsg/rpmsg_char.h |   2 +
>  drivers/rpmsg/rpmsg_ctrl.c | 231 +++++++++++++++++++++++++++++++++++++
>  5 files changed, 245 insertions(+), 179 deletions(-)
>  create mode 100644 drivers/rpmsg/rpmsg_ctrl.c
> 
> diff --git a/drivers/rpmsg/Kconfig b/drivers/rpmsg/Kconfig
> index 0b4407abdf13..d822ec9ec692 100644
> --- a/drivers/rpmsg/Kconfig
> +++ b/drivers/rpmsg/Kconfig
> @@ -10,11 +10,20 @@ config RPMSG_CHAR
>  	tristate "RPMSG device interface"
>  	depends on RPMSG
>  	depends on NET
> +	select RPMSG_CTRL
>  	help
>  	  Say Y here to export rpmsg endpoints as device files, usually found
>  	  in /dev. They make it possible for user-space programs to send and
>  	  receive rpmsg packets.
>  
> +config RPMSG_CTRL
> +	tristate "RPMSG control interface"
> +	depends on RPMSG
> +	help
> +	  Say Y here to enable the support of the /dev/rpmsg_ctrlX API. This API
> +	  allows user-space programs to create endpoints with specific service name,
> +	  source and destination addresses.
> +
>  config RPMSG_NS
>  	tristate "RPMSG name service announcement"
>  	depends on RPMSG
> diff --git a/drivers/rpmsg/Makefile b/drivers/rpmsg/Makefile
> index 8d452656f0ee..58e3b382e316 100644
> --- a/drivers/rpmsg/Makefile
> +++ b/drivers/rpmsg/Makefile
> @@ -1,6 +1,7 @@
>  # SPDX-License-Identifier: GPL-2.0
>  obj-$(CONFIG_RPMSG)		+= rpmsg_core.o
>  obj-$(CONFIG_RPMSG_CHAR)	+= rpmsg_char.o
> +obj-$(CONFIG_RPMSG_CTRL)	+= rpmsg_ctrl.o
>  obj-$(CONFIG_RPMSG_NS)		+= rpmsg_ns.o
>  obj-$(CONFIG_RPMSG_MTK_SCP)	+= mtk_rpmsg.o
>  qcom_glink-objs			:= qcom_glink_native.o qcom_glink_ssr.o
> diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
> index b9df8dc4365f..21ef9d9eccd7 100644
> --- a/drivers/rpmsg/rpmsg_char.c
> +++ b/drivers/rpmsg/rpmsg_char.c
> @@ -26,33 +26,14 @@
>  #include "rpmsg_char.h"
>  #include "rpmsg_internal.h"
>  
> -#define RPMSG_DEV_MAX	(MINORMASK + 1)
> -
>  static dev_t rpmsg_major;
> -static struct class *rpmsg_class;
>  
> -static DEFINE_IDA(rpmsg_ctrl_ida);
>  static DEFINE_IDA(rpmsg_ept_ida);
>  static DEFINE_IDA(rpmsg_minor_ida);
>  
>  #define dev_to_eptdev(dev) container_of(dev, struct rpmsg_eptdev, dev)
>  #define cdev_to_eptdev(i_cdev) container_of(i_cdev, struct rpmsg_eptdev, cdev)
>  
> -#define dev_to_ctrldev(dev) container_of(dev, struct rpmsg_ctrldev, dev)
> -#define cdev_to_ctrldev(i_cdev) container_of(i_cdev, struct rpmsg_ctrldev, cdev)
> -
> -/**
> - * struct rpmsg_ctrldev - control device for instantiating endpoint devices
> - * @rpdev:	underlaying rpmsg device
> - * @cdev:	cdev for the ctrl device
> - * @dev:	device for the ctrl device
> - */
> -struct rpmsg_ctrldev {
> -	struct rpmsg_device *rpdev;
> -	struct cdev cdev;
> -	struct device dev;
> -};
> -
>  /**
>   * struct rpmsg_eptdev - endpoint device context
>   * @dev:	endpoint device
> @@ -409,169 +390,13 @@ int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent
>  }
>  EXPORT_SYMBOL(rpmsg_chrdev_create_eptdev);
>  
> -static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp)
> -{
> -	struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);
> -
> -	get_device(&ctrldev->dev);
> -	filp->private_data = ctrldev;
> -
> -	return 0;
> -}
> -
> -static int rpmsg_ctrldev_release(struct inode *inode, struct file *filp)
> -{
> -	struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);
> -
> -	put_device(&ctrldev->dev);
> -
> -	return 0;
> -}
> -
> -static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
> -				unsigned long arg)
> -{
> -	struct rpmsg_ctrldev *ctrldev = fp->private_data;
> -	void __user *argp = (void __user *)arg;
> -	struct rpmsg_endpoint_info eptinfo;
> -	struct rpmsg_channel_info chinfo;
> -
> -	if (cmd != RPMSG_CREATE_EPT_IOCTL)
> -		return -EINVAL;
> -
> -	if (copy_from_user(&eptinfo, argp, sizeof(eptinfo)))
> -		return -EFAULT;
> -
> -	memcpy(chinfo.name, eptinfo.name, RPMSG_NAME_SIZE);
> -	chinfo.name[RPMSG_NAME_SIZE-1] = '\0';
> -	chinfo.src = eptinfo.src;
> -	chinfo.dst = eptinfo.dst;
> -
> -	return rpmsg_chrdev_create_eptdev(ctrldev->rpdev, &ctrldev->dev, chinfo, rpmsg_class);
> -};
> -
> -static const struct file_operations rpmsg_ctrldev_fops = {
> -	.owner = THIS_MODULE,
> -	.open = rpmsg_ctrldev_open,
> -	.release = rpmsg_ctrldev_release,
> -	.unlocked_ioctl = rpmsg_ctrldev_ioctl,
> -	.compat_ioctl = compat_ptr_ioctl,
> -};
> -
> -static void rpmsg_ctrldev_release_device(struct device *dev)
> -{
> -	struct rpmsg_ctrldev *ctrldev = dev_to_ctrldev(dev);
> -
> -	ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
> -	ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
> -	cdev_del(&ctrldev->cdev);
> -	kfree(ctrldev);
> -}
> -
> -static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev)
> -{
> -	struct rpmsg_ctrldev *ctrldev;
> -	struct device *dev;
> -	int ret;
> -
> -	ctrldev = kzalloc(sizeof(*ctrldev), GFP_KERNEL);
> -	if (!ctrldev)
> -		return -ENOMEM;
> -
> -	ctrldev->rpdev = rpdev;
> -
> -	dev = &ctrldev->dev;
> -	device_initialize(dev);
> -	dev->parent = &rpdev->dev;
> -	dev->class = rpmsg_class;
> -
> -	cdev_init(&ctrldev->cdev, &rpmsg_ctrldev_fops);
> -	ctrldev->cdev.owner = THIS_MODULE;
> -
> -	ret = ida_simple_get(&rpmsg_minor_ida, 0, RPMSG_DEV_MAX, GFP_KERNEL);
> -	if (ret < 0)
> -		goto free_ctrldev;
> -	dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
> -
> -	ret = ida_simple_get(&rpmsg_ctrl_ida, 0, 0, GFP_KERNEL);
> -	if (ret < 0)
> -		goto free_minor_ida;
> -	dev->id = ret;
> -	dev_set_name(&ctrldev->dev, "rpmsg_ctrl%d", ret);
> -
> -	ret = cdev_add(&ctrldev->cdev, dev->devt, 1);
> -	if (ret)
> -		goto free_ctrl_ida;
> -
> -	/* We can now rely on the release function for cleanup */
> -	dev->release = rpmsg_ctrldev_release_device;
> -
> -	ret = device_add(dev);
> -	if (ret) {
> -		dev_err(&rpdev->dev, "device_add failed: %d\n", ret);
> -		put_device(dev);
> -	}
> -
> -	dev_set_drvdata(&rpdev->dev, ctrldev);
> -
> -	return ret;
> -
> -free_ctrl_ida:
> -	ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
> -free_minor_ida:
> -	ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
> -free_ctrldev:
> -	put_device(dev);
> -	kfree(ctrldev);
> -
> -	return ret;
> -}
> -
> -static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
> -{
> -	struct rpmsg_ctrldev *ctrldev = dev_get_drvdata(&rpdev->dev);
> -	int ret;
> -
> -	/* Destroy all endpoints */
> -	ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_chrdev_destroy_eptdev);
> -	if (ret)
> -		dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret);
> -
> -	device_del(&ctrldev->dev);
> -	put_device(&ctrldev->dev);
> -}
> -
> -static struct rpmsg_driver rpmsg_chrdev_driver = {
> -	.probe = rpmsg_chrdev_probe,
> -	.remove = rpmsg_chrdev_remove,
> -	.drv = {
> -		.name = "rpmsg_chrdev",
> -	},
> -};
> -
>  static int rpmsg_chrdev_init(void)
>  {
>  	int ret;
>  
> -	ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg");
> -	if (ret < 0) {
> +	ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg_char");
> +	if (ret < 0)
>  		pr_err("rpmsg: failed to allocate char dev region\n");
> -		return ret;
> -	}
> -
> -	rpmsg_class = class_create(THIS_MODULE, "rpmsg");
> -	if (IS_ERR(rpmsg_class)) {
> -		pr_err("failed to create rpmsg class\n");
> -		unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
> -		return PTR_ERR(rpmsg_class);
> -	}
> -
> -	ret = register_rpmsg_driver(&rpmsg_chrdev_driver);
> -	if (ret < 0) {
> -		pr_err("rpmsgchr: failed to register rpmsg driver\n");
> -		class_destroy(rpmsg_class);
> -		unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
> -	}
>  
>  	return ret;
>  }
> @@ -579,8 +404,6 @@ postcore_initcall(rpmsg_chrdev_init);
>  
>  static void rpmsg_chrdev_exit(void)
>  {
> -	unregister_rpmsg_driver(&rpmsg_chrdev_driver);
> -	class_destroy(rpmsg_class);
>  	unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
>  }
>  module_exit(rpmsg_chrdev_exit);
> diff --git a/drivers/rpmsg/rpmsg_char.h b/drivers/rpmsg/rpmsg_char.h
> index 379d2ae2bee8..f20a215073c3 100644
> --- a/drivers/rpmsg/rpmsg_char.h
> +++ b/drivers/rpmsg/rpmsg_char.h
> @@ -6,6 +6,8 @@
>  #ifndef __RPMSG_CHRDEV_H__
>  #define __RPMSG_CHRDEV_H__
>  
> +#define RPMSG_DEV_MAX	(MINORMASK + 1)
> +
>  #if IS_REACHABLE(CONFIG_RPMSG_CHAR)
>  /**
>   * rpmsg_chrdev_create_eptdev() - register char device based on an endpoint
> diff --git a/drivers/rpmsg/rpmsg_ctrl.c b/drivers/rpmsg/rpmsg_ctrl.c
> new file mode 100644
> index 000000000000..a5bb9ed97f32
> --- /dev/null
> +++ b/drivers/rpmsg/rpmsg_ctrl.c
> @@ -0,0 +1,231 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2021, STMicroelectronics
> + * Copyright (c) 2016, Linaro Ltd.
> + * Copyright (c) 2012, Michal Simek <monstr@monstr.eu>
> + * Copyright (c) 2012, PetaLogix
> + * Copyright (c) 2011, Texas Instruments, Inc.
> + * Copyright (c) 2011, Google, Inc.
> + *
> + * Based on rpmsg performance statistics driver by Michal Simek, which in turn
> + * was based on TI & Google OMX rpmsg driver.
> + */
> +#include <linux/cdev.h>
> +#include <linux/device.h>
> +#include <linux/fs.h>
> +#include <linux/idr.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/rpmsg.h>
> +#include <linux/slab.h>
> +#include <uapi/linux/rpmsg.h>
> +
> +#include "rpmsg_char.h"
> +#include "rpmsg_internal.h"
> +
> +static dev_t rpmsg_major;
> +struct class *rpmsg_class;
> +
> +static DEFINE_IDA(rpmsg_ctrl_ida);
> +static DEFINE_IDA(rpmsg_minor_ida);
> +
> +#define dev_to_ctrldev(dev) container_of(dev, struct rpmsg_ctrldev, dev)
> +#define cdev_to_ctrldev(i_cdev) container_of(i_cdev, struct rpmsg_ctrldev, cdev)
> +
> +/**
> + * struct rpmsg_ctrldev - control device for instantiating endpoint devices
> + * @rpdev:	underlaying rpmsg device
> + * @cdev:	cdev for the ctrl device
> + * @dev:	device for the ctrl device
> + */
> +struct rpmsg_ctrldev {
> +	struct rpmsg_device *rpdev;
> +	struct cdev cdev;
> +	struct device dev;
> +};
> +
> +static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp)
> +{
> +	struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);
> +
> +	get_device(&ctrldev->dev);
> +	filp->private_data = ctrldev;
> +
> +	return 0;
> +}
> +
> +static int rpmsg_ctrldev_release(struct inode *inode, struct file *filp)
> +{
> +	struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);
> +
> +	put_device(&ctrldev->dev);
> +
> +	return 0;
> +}
> +
> +static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
> +				unsigned long arg)
> +{
> +	struct rpmsg_ctrldev *ctrldev = fp->private_data;
> +	void __user *argp = (void __user *)arg;
> +	struct rpmsg_endpoint_info eptinfo;
> +	struct rpmsg_channel_info chinfo;
> +
> +	if (cmd != RPMSG_CREATE_EPT_IOCTL)
> +		return -EINVAL;
> +
> +	if (copy_from_user(&eptinfo, argp, sizeof(eptinfo)))
> +		return -EFAULT;
> +
> +	memcpy(chinfo.name, eptinfo.name, RPMSG_NAME_SIZE);
> +	chinfo.name[RPMSG_NAME_SIZE - 1] = '\0';
> +	chinfo.src = eptinfo.src;
> +	chinfo.dst = eptinfo.dst;
> +
> +	return rpmsg_chrdev_create_eptdev(ctrldev->rpdev, &ctrldev->dev, chinfo, rpmsg_class);
> +};
> +
> +static const struct file_operations rpmsg_ctrldev_fops = {
> +	.owner = THIS_MODULE,
> +	.open = rpmsg_ctrldev_open,
> +	.release = rpmsg_ctrldev_release,
> +	.unlocked_ioctl = rpmsg_ctrldev_ioctl,
> +	.compat_ioctl = compat_ptr_ioctl,
> +};
> +
> +static void rpmsg_ctrldev_release_device(struct device *dev)
> +{
> +	struct rpmsg_ctrldev *ctrldev = dev_to_ctrldev(dev);
> +
> +	ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
> +	ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
> +	cdev_del(&ctrldev->cdev);
> +	kfree(ctrldev);
> +}
> +
> +static int rpmsg_ctrldev_probe(struct rpmsg_device *rpdev)
> +{
> +	struct rpmsg_ctrldev *ctrldev;
> +	struct device *dev;
> +	int ret;
> +
> +	ctrldev = kzalloc(sizeof(*ctrldev), GFP_KERNEL);
> +	if (!ctrldev)
> +		return -ENOMEM;
> +
> +	ctrldev->rpdev = rpdev;
> +
> +	dev = &ctrldev->dev;
> +	device_initialize(dev);
> +	dev->parent = &rpdev->dev;
> +	dev->class = rpmsg_class;
> +
> +	cdev_init(&ctrldev->cdev, &rpmsg_ctrldev_fops);
> +	ctrldev->cdev.owner = THIS_MODULE;
> +
> +	ret = ida_simple_get(&rpmsg_minor_ida, 0, RPMSG_DEV_MAX, GFP_KERNEL);
> +	if (ret < 0)
> +		goto free_ctrldev;
> +	dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
> +
> +	ret = ida_simple_get(&rpmsg_ctrl_ida, 0, 0, GFP_KERNEL);
> +	if (ret < 0)
> +		goto free_minor_ida;
> +	dev->id = ret;
> +	dev_set_name(&ctrldev->dev, "rpmsg_ctrl%d", ret);
> +
> +	ret = cdev_add(&ctrldev->cdev, dev->devt, 1);
> +	if (ret)
> +		goto free_ctrl_ida;
> +
> +	/* We can now rely on the release function for cleanup */
> +	dev->release = rpmsg_ctrldev_release_device;
> +
> +	ret = device_add(dev);
> +	if (ret) {
> +		dev_err(&rpdev->dev, "device_add failed: %d\n", ret);
> +		put_device(dev);
> +	}
> +
> +	dev_set_drvdata(&rpdev->dev, ctrldev);
> +
> +	return ret;
> +
> +free_ctrl_ida:
> +	ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
> +free_minor_ida:
> +	ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
> +free_ctrldev:
> +	put_device(dev);
> +	kfree(ctrldev);
> +
> +	return ret;
> +}
> +
> +static void rpmsg_ctrldev_remove(struct rpmsg_device *rpdev)
> +{
> +	struct rpmsg_ctrldev *ctrldev = dev_get_drvdata(&rpdev->dev);
> +	int ret;
> +
> +	/* Destroy all endpoints */
> +	ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_chrdev_destroy_eptdev);
> +	if (ret)
> +		dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret);
> +
> +	device_del(&ctrldev->dev);
> +	put_device(&ctrldev->dev);
> +}
> +
> +static struct rpmsg_driver rpmsg_ctrldev_driver = {
> +	.probe = rpmsg_ctrldev_probe,
> +	.remove = rpmsg_ctrldev_remove,
> +	.drv = {
> +		.name = "rpmsg_chrdev",
> +	},
> +};
> +
> +static int rpmsg_ctrldev_init(void)
> +{
> +	int ret;
> +
> +	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");
> +		return ret;
> +	}
> +
> +	rpmsg_class = class_create(THIS_MODULE, "rpmsg");

This class thing really bothers me.  Keeping this here means that rpmsg_eptdevs
created from user space will be associated to this rpmsg_class but those created
from the name service won't.  As such I propose to move this to rpmsg_char and
simply not associate the control device to the class.

Otherwise we'd have to introduce some mechanic only to deal with the creation of
the class and I don't think it is worth.  We can revise that approach if someone
complains we broke their user space. 


> +	if (IS_ERR(rpmsg_class)) {
> +		pr_err("failed to create rpmsg class\n");
> +		ret = PTR_ERR(rpmsg_class);
> +		goto free_region;
> +	}
> +
> +	ret = register_rpmsg_driver(&rpmsg_ctrldev_driver);
> +	if (ret < 0) {
> +		pr_err("rpmsg ctrl: failed to register rpmsg driver\n");
> +		goto free_class;
> +	}
> +
> +	return 0;
> +
> +free_class:
> +	class_destroy(rpmsg_class);
> +free_region:
> +	unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
> +
> +	return ret;
> +}
> +postcore_initcall(rpmsg_ctrldev_init);
> +
> +static void rpmsg_ctrldev_exit(void)
> +{
> +	unregister_rpmsg_driver(&rpmsg_ctrldev_driver);
> +	class_destroy(rpmsg_class);
> +	unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
> +}
> +module_exit(rpmsg_ctrldev_exit);
> +
> +MODULE_DESCRIPTION("rpmsg control interface");
> +MODULE_ALIAS("rpmsg:" KBUILD_MODNAME);
> +MODULE_LICENSE("GPL v2");
> -- 
> 2.17.1
> 

Re: [PATCH v2 3/7] rpmsg: Update rpmsg_chrdev_register_device function

[Mathieu Poirier]

On Tue, Apr 13, 2021 at 03:44:54PM +0200, Arnaud Pouliquen wrote:
> The rpmsg_chrdev driver has been replaced by the rpmsg_ctrl driver
> for the /dev/rpmsg_ctrlX devices management. The reference for the
> driver override is now the rpmsg_ctrl.
> 
> Update the rpmsg_chrdev_register_device function to reflect the update,
> and rename the function to use the rpmsg_ctrldev prefix.
> 
> The platform drivers are updated accordingly.
> 
> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
> 
> ---
> update from v1
> - move the rename of the rpmsg_ctrl driver from previous patch to
>   this one.
> ---
>  drivers/rpmsg/qcom_glink_native.c | 2 +-
>  drivers/rpmsg/qcom_smd.c          | 2 +-
>  drivers/rpmsg/rpmsg_ctrl.c        | 2 +-
>  drivers/rpmsg/rpmsg_internal.h    | 8 ++++----
>  drivers/rpmsg/virtio_rpmsg_bus.c  | 2 +-
>  5 files changed, 8 insertions(+), 8 deletions(-)
>

Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
 
> diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
> index 05533c71b10e..7d7e809800ec 100644
> --- a/drivers/rpmsg/qcom_glink_native.c
> +++ b/drivers/rpmsg/qcom_glink_native.c
> @@ -1642,7 +1642,7 @@ static int qcom_glink_create_chrdev(struct qcom_glink *glink)
>  	rpdev->dev.parent = glink->dev;
>  	rpdev->dev.release = qcom_glink_device_release;
>  
> -	return rpmsg_chrdev_register_device(rpdev);
> +	return rpmsg_ctrldev_register_device(rpdev);
>  }
>  
>  struct qcom_glink *qcom_glink_native_probe(struct device *dev,
> diff --git a/drivers/rpmsg/qcom_smd.c b/drivers/rpmsg/qcom_smd.c
> index 8da1b5cb31b3..d223e438d17c 100644
> --- a/drivers/rpmsg/qcom_smd.c
> +++ b/drivers/rpmsg/qcom_smd.c
> @@ -1113,7 +1113,7 @@ static int qcom_smd_create_chrdev(struct qcom_smd_edge *edge)
>  	qsdev->rpdev.dev.parent = &edge->dev;
>  	qsdev->rpdev.dev.release = qcom_smd_release_device;
>  
> -	return rpmsg_chrdev_register_device(&qsdev->rpdev);
> +	return rpmsg_ctrldev_register_device(&qsdev->rpdev);
>  }
>  
>  /*
> diff --git a/drivers/rpmsg/rpmsg_ctrl.c b/drivers/rpmsg/rpmsg_ctrl.c
> index a5bb9ed97f32..059c228d0045 100644
> --- a/drivers/rpmsg/rpmsg_ctrl.c
> +++ b/drivers/rpmsg/rpmsg_ctrl.c
> @@ -180,7 +180,7 @@ static struct rpmsg_driver rpmsg_ctrldev_driver = {
>  	.probe = rpmsg_ctrldev_probe,
>  	.remove = rpmsg_ctrldev_remove,
>  	.drv = {
> -		.name = "rpmsg_chrdev",
> +		.name = "rpmsg_ctrl",
>  	},
>  };
>  
> diff --git a/drivers/rpmsg/rpmsg_internal.h b/drivers/rpmsg/rpmsg_internal.h
> index a76c344253bf..8c500a8f29aa 100644
> --- a/drivers/rpmsg/rpmsg_internal.h
> +++ b/drivers/rpmsg/rpmsg_internal.h
> @@ -82,16 +82,16 @@ struct rpmsg_device *rpmsg_create_channel(struct rpmsg_device *rpdev,
>  int rpmsg_release_channel(struct rpmsg_device *rpdev,
>  			  struct rpmsg_channel_info *chinfo);
>  /**
> - * rpmsg_chrdev_register_device() - register chrdev device based on rpdev
> + * rpmsg_ctrl_register_device() - register a char device for control based on rpdev
>   * @rpdev:	prepared rpdev to be used for creating endpoints
>   *
>   * This function wraps rpmsg_register_device() preparing the rpdev for use as
>   * basis for the rpmsg chrdev.
>   */
> -static inline int rpmsg_chrdev_register_device(struct rpmsg_device *rpdev)
> +static inline int rpmsg_ctrldev_register_device(struct rpmsg_device *rpdev)
>  {
> -	strcpy(rpdev->id.name, "rpmsg_chrdev");
> -	rpdev->driver_override = "rpmsg_chrdev";
> +	strcpy(rpdev->id.name, "rpmsg_ctrl");
> +	rpdev->driver_override = "rpmsg_ctrl";
>  
>  	return rpmsg_register_device(rpdev);
>  }
> diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c
> index 8e49a3bacfc7..e42234a3e2ab 100644
> --- a/drivers/rpmsg/virtio_rpmsg_bus.c
> +++ b/drivers/rpmsg/virtio_rpmsg_bus.c
> @@ -840,7 +840,7 @@ static struct rpmsg_device *rpmsg_virtio_add_ctrl_dev(struct virtio_device *vdev
>  	rpdev_ctrl->dev.release = virtio_rpmsg_release_device;
>  	rpdev_ctrl->little_endian = virtio_is_little_endian(vrp->vdev);
>  
> -	err = rpmsg_chrdev_register_device(rpdev_ctrl);
> +	err = rpmsg_ctrldev_register_device(rpdev_ctrl);
>  	if (err) {
>  		kfree(vch);
>  		return ERR_PTR(err);
> -- 
> 2.17.1
> 

Re: [PATCH v2 1/7] rpmsg: char: Export eptdev create an destroy functions

[Arnaud POULIQUEN]

hello Mathieu

On 4/21/21 7:52 PM, Mathieu Poirier wrote:
> On Tue, Apr 13, 2021 at 03:44:52PM +0200, Arnaud Pouliquen wrote:
>> To prepare the split of the code related to the control (ctrldev)
>> and the endpoint (eptdev) devices in 2 separate files:
>>
>> - Rename and export the functions in rpmsg_char.h.
>>
>> - Suppress the dependency with the rpmsg_ctrldev struct in the
>>   rpmsg_chrdev_create_eptdev function.
>>
>> - The rpmsg class is provided as parameter in rpmsg_chrdev_create_eptdev,
>>   because the class is associated to the control part.
>>
>> Suggested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
>> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
>> ---
>>  drivers/rpmsg/rpmsg_char.c | 19 +++++++++------
>>  drivers/rpmsg/rpmsg_char.h | 50 ++++++++++++++++++++++++++++++++++++++
>>  2 files changed, 61 insertions(+), 8 deletions(-)
>>  create mode 100644 drivers/rpmsg/rpmsg_char.h
>>
>> diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
>> index 2bebc9b2d163..b9df8dc4365f 100644
>> --- a/drivers/rpmsg/rpmsg_char.c
>> +++ b/drivers/rpmsg/rpmsg_char.c
>> @@ -1,5 +1,6 @@
>>  // SPDX-License-Identifier: GPL-2.0
>>  /*
>> + * Copyright (C) 2021, STMicroelectronics
>>   * Copyright (c) 2016, Linaro Ltd.
>>   * Copyright (c) 2012, Michal Simek <monstr@monstr.eu>
>>   * Copyright (c) 2012, PetaLogix
>> @@ -22,6 +23,7 @@
>>  #include <linux/uaccess.h>
>>  #include <uapi/linux/rpmsg.h>
>>  
>> +#include "rpmsg_char.h"
>>  #include "rpmsg_internal.h"
>>  
>>  #define RPMSG_DEV_MAX	(MINORMASK + 1)
>> @@ -78,7 +80,7 @@ struct rpmsg_eptdev {
>>  	wait_queue_head_t readq;
>>  };
>>  
>> -static int rpmsg_eptdev_destroy(struct device *dev, void *data)
>> +int rpmsg_chrdev_destroy_eptdev(struct device *dev, void *data)
> 
> Shouldn't this be rpmsg_chrdev_eptdev_destroy()?  I've been wondering about the
> flipping of destroy and eptdev...  The same for rpmsg_chrdev_create_eptdev().

As the function is exported i prefered to follow name srtructure that is
commonly used: <module>_<action>_<object>

But it is not a rule, so please just tell me if you prefer that i rename the
functions  rpmsg_chrdev_eptdev_xxxx?

Thanks,
Arnaud

> 
> With that:
> 
> Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> 
>>  {
>>  	struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);
>>  
>> @@ -97,6 +99,7 @@ static int rpmsg_eptdev_destroy(struct device *dev, void *data)
>>  
>>  	return 0;
>>  }
>> +EXPORT_SYMBOL(rpmsg_chrdev_destroy_eptdev);
>>  
>>  static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len,
>>  			void *priv, u32 addr)
>> @@ -280,7 +283,7 @@ static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
>>  	if (cmd != RPMSG_DESTROY_EPT_IOCTL)
>>  		return -EINVAL;
>>  
>> -	return rpmsg_eptdev_destroy(&eptdev->dev, NULL);
>> +	return rpmsg_chrdev_destroy_eptdev(&eptdev->dev, NULL);
>>  }
>>  
>>  static const struct file_operations rpmsg_eptdev_fops = {
>> @@ -339,10 +342,9 @@ static void rpmsg_eptdev_release_device(struct device *dev)
>>  	kfree(eptdev);
>>  }
>>  
>> -static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev,
>> -			       struct rpmsg_channel_info chinfo)
>> +int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent,
>> +			       struct rpmsg_channel_info chinfo, struct class *rpmsg_class)
>>  {
>> -	struct rpmsg_device *rpdev = ctrldev->rpdev;
>>  	struct rpmsg_eptdev *eptdev;
>>  	struct device *dev;
>>  	int ret;
>> @@ -362,7 +364,7 @@ static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev,
>>  
>>  	device_initialize(dev);
>>  	dev->class = rpmsg_class;
>> -	dev->parent = &ctrldev->dev;
>> +	dev->parent = parent;
>>  	dev->groups = rpmsg_eptdev_groups;
>>  	dev_set_drvdata(dev, eptdev);
>>  
>> @@ -405,6 +407,7 @@ static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev,
>>  
>>  	return ret;
>>  }
>> +EXPORT_SYMBOL(rpmsg_chrdev_create_eptdev);
>>  
>>  static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp)
>>  {
>> @@ -444,7 +447,7 @@ static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
>>  	chinfo.src = eptinfo.src;
>>  	chinfo.dst = eptinfo.dst;
>>  
>> -	return rpmsg_eptdev_create(ctrldev, chinfo);
>> +	return rpmsg_chrdev_create_eptdev(ctrldev->rpdev, &ctrldev->dev, chinfo, rpmsg_class);
>>  };
>>  
>>  static const struct file_operations rpmsg_ctrldev_fops = {
>> @@ -530,7 +533,7 @@ static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
>>  	int ret;
>>  
>>  	/* Destroy all endpoints */
>> -	ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_eptdev_destroy);
>> +	ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_chrdev_destroy_eptdev);
>>  	if (ret)
>>  		dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret);
>>  
>> diff --git a/drivers/rpmsg/rpmsg_char.h b/drivers/rpmsg/rpmsg_char.h
>> new file mode 100644
>> index 000000000000..379d2ae2bee8
>> --- /dev/null
>> +++ b/drivers/rpmsg/rpmsg_char.h
>> @@ -0,0 +1,50 @@
>> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
>> +/*
>> + * Copyright (C) STMicroelectronics 2021.
>> + */
>> +
>> +#ifndef __RPMSG_CHRDEV_H__
>> +#define __RPMSG_CHRDEV_H__
>> +
>> +#if IS_REACHABLE(CONFIG_RPMSG_CHAR)
>> +/**
>> + * rpmsg_chrdev_create_eptdev() - register char device based on an endpoint
>> + * @rpdev:  prepared rpdev to be used for creating endpoints
>> + * @parent: parent device
>> + * @chinfo: assiated endpoint channel information.
>> + *
>> + * This function create a new rpmsg char endpoint device to instantiate a new
>> + * endpoint based on chinfo information.
>> + */
>> +int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent,
>> +			       struct rpmsg_channel_info chinfo, struct class *rpmsg_class);
>> +
>> +/**
>> + * rpmsg_chrdev_destroy_eptdev() - destroy created char device endpoint.
>> + * @data: private data associated to the endpoint device
>> + *
>> + * This function destroys a rpmsg char endpoint device created by the RPMSG_DESTROY_EPT_IOCTL
>> + * control.
>> + */
>> +int rpmsg_chrdev_destroy_eptdev(struct device *dev, void *data);
>> +
>> +#else  /*IS_REACHABLE(CONFIG_RPMSG_CHAR) */
>> +
>> +static inline int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent,
>> +					     struct rpmsg_channel_info chinfo,
>> +					     struct class *rpmsg_class)
>> +{
>> +	return -EINVAL;
>> +}
>> +
>> +static inline int rpmsg_chrdev_destroy_eptdev(struct device *dev, void *data)
>> +{
>> +	/* This shouldn't be possible */
>> +	WARN_ON(1);
>> +
>> +	return 0;
>> +}
>> +
>> +#endif /*IS_REACHABLE(CONFIG_RPMSG_CHAR) */
>> +
>> +#endif /*__RPMSG_CHRDEV_H__ */
>> -- 
>> 2.17.1
>>

Re: [PATCH v2 2/7] rpmsg: Move the rpmsg control device from rpmsg_char to rpmsg_ctrl

[Arnaud POULIQUEN]

On 4/21/21 8:04 PM, Mathieu Poirier wrote:
> On Tue, Apr 13, 2021 at 03:44:53PM +0200, Arnaud Pouliquen wrote:
>> Create the rpmsg_ctrl.c module and move the code related to the
>> rpmsg_ctrldev device in this new module.
>>
>> Add the dependency between rpmsg_char and rpmsg_ctrl in the
>> kconfig file.
>>
>> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
>> ---
>> update from v1:
>> - keep "rpmsg_chrdev" driver name in rpmsg_ctrl, driver will be renamed
>>   in next path that renames the rpmsg_chrdev_create_eptdev.
>> - rename the chardev regions
>> - move RPMSG_DEV_MAX to rpmsg_char.h
>> ---
>>  drivers/rpmsg/Kconfig      |   9 ++
>>  drivers/rpmsg/Makefile     |   1 +
>>  drivers/rpmsg/rpmsg_char.c | 181 +----------------------------
>>  drivers/rpmsg/rpmsg_char.h |   2 +
>>  drivers/rpmsg/rpmsg_ctrl.c | 231 +++++++++++++++++++++++++++++++++++++
>>  5 files changed, 245 insertions(+), 179 deletions(-)
>>  create mode 100644 drivers/rpmsg/rpmsg_ctrl.c
>>
>> diff --git a/drivers/rpmsg/Kconfig b/drivers/rpmsg/Kconfig
>> index 0b4407abdf13..d822ec9ec692 100644
>> --- a/drivers/rpmsg/Kconfig

snip[...]

>> +static int rpmsg_ctrldev_init(void)
>> +{
>> +	int ret;
>> +
>> +	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");
>> +		return ret;
>> +	}
>> +
>> +	rpmsg_class = class_create(THIS_MODULE, "rpmsg");
> 
> This class thing really bothers me.  Keeping this here means that rpmsg_eptdevs
> created from user space will be associated to this rpmsg_class but those created
> from the name service won't.  As such I propose to move this to rpmsg_char and
> simply not associate the control device to the class.
> 
> Otherwise we'd have to introduce some mechanic only to deal with the creation of
> the class and I don't think it is worth.  We can revise that approach if someone
> complains we broke their user space. 

I agree with that as it was my first proposed approach here [1]

[1] https://www.spinics.net/lists/linux-arm-msm/msg81194.html

Thanks,
Arnaud

> 
> 
>> +	if (IS_ERR(rpmsg_class)) {
>> +		pr_err("failed to create rpmsg class\n");
>> +		ret = PTR_ERR(rpmsg_class);
>> +		goto free_region;
>> +	}
>> +
>> +	ret = register_rpmsg_driver(&rpmsg_ctrldev_driver);
>> +	if (ret < 0) {
>> +		pr_err("rpmsg ctrl: failed to register rpmsg driver\n");
>> +		goto free_class;
>> +	}
>> +
>> +	return 0;
>> +
>> +free_class:
>> +	class_destroy(rpmsg_class);
>> +free_region:
>> +	unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
>> +
>> +	return ret;
>> +}
>> +postcore_initcall(rpmsg_ctrldev_init);
>> +
>> +static void rpmsg_ctrldev_exit(void)
>> +{
>> +	unregister_rpmsg_driver(&rpmsg_ctrldev_driver);
>> +	class_destroy(rpmsg_class);
>> +	unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
>> +}
>> +module_exit(rpmsg_ctrldev_exit);
>> +
>> +MODULE_DESCRIPTION("rpmsg control interface");
>> +MODULE_ALIAS("rpmsg:" KBUILD_MODNAME);
>> +MODULE_LICENSE("GPL v2");
>> -- 
>> 2.17.1
>>

Re: [PATCH v2 5/7] rpmsg: char: Introduce a rpmsg driver for the rpmsg char device

[Arnaud POULIQUEN]

On 4/21/21 7:40 PM, Mathieu Poirier wrote:
> Good day Arnaud,
> 
> On Tue, Apr 13, 2021 at 03:44:56PM +0200, Arnaud Pouliquen wrote:
>> A rpmsg char device allows to probe the endpoint device on a remote name
>> service announcement.
>>
>> With this patch the /dev/rpmsgX interface is created either by a user
>> application or by the remote firmware.
>>
>> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
>>
>> ---
>> update from V1:
>>  - add missing unregister_rpmsg_driver call on module exit.
>>
>> ---
>>  drivers/rpmsg/rpmsg_char.c | 59 +++++++++++++++++++++++++++++++++++++-
>>  1 file changed, 58 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
>> index a64249d83172..4606787b7011 100644
>> --- a/drivers/rpmsg/rpmsg_char.c
>> +++ b/drivers/rpmsg/rpmsg_char.c
>> @@ -26,6 +26,8 @@
>>  #include "rpmsg_char.h"
>>  #include "rpmsg_internal.h"
>>  
>> +#define RPMSG_CHAR_DEVNAME "rpmsg-raw"
>> +
> 
> Why not simply call it rpmsg-char?

I would avoid to link the rpmsg name service to the Linux Kernel device.

> 
>>  static dev_t rpmsg_major;
>>  
>>  static DEFINE_IDA(rpmsg_ept_ida);
>> @@ -403,13 +405,67 @@ int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent
>>  }
>>  EXPORT_SYMBOL(rpmsg_chrdev_create_eptdev);
>>  
>> +static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev)
>> +{
>> +	struct rpmsg_channel_info chinfo;
>> +	struct rpmsg_eptdev *eptdev;
>> +
>> +	if (!rpdev->ept)
>> +		return -EINVAL;
>> +
>> +	memcpy(chinfo.name, RPMSG_CHAR_DEVNAME, sizeof(RPMSG_CHAR_DEVNAME));
>> +	chinfo.src = rpdev->src;
>> +	chinfo.dst = rpdev->dst;
>> +
>> +	eptdev = __rpmsg_chrdev_create_eptdev(rpdev, &rpdev->dev, chinfo, NULL);
>> +	if (IS_ERR(eptdev))
>> +		return PTR_ERR(eptdev);
>> +
>> +	/* Set the private field of the default endpoint to retrieve context on callback. */
>> +	rpdev->ept->priv = eptdev;
> 
> This is already done in rpmsg_create_ept() when rpmsg_eptdev_open() is called.
> 
>> +
>> +	return 0;
>> +}
>> +
>> +static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
>> +{
>> +	int ret;
>> +
>> +	ret = device_for_each_child(&rpdev->dev, NULL, rpmsg_chrdev_destroy_eptdev);
>> +	if (ret)
>> +		dev_warn(&rpdev->dev, "failed to destroy endpoints: %d\n", ret);
>> +}
>> +
>> +static struct rpmsg_device_id rpmsg_chrdev_id_table[] = {
>> +	{ .name	= RPMSG_CHAR_DEVNAME },
>> +	{ },
>> +};
>> +
>> +static struct rpmsg_driver rpmsg_chrdev_driver = {
>> +	.probe = rpmsg_chrdev_probe,
>> +	.remove = rpmsg_chrdev_remove,
>> +	.id_table = rpmsg_chrdev_id_table,
>> +	.callback = rpmsg_ept_cb,
> 
> Not sure why we need a callback associated to this driver when
> rpmsg_eptdev_open() already creates and rpmsg_endpoint.  To me the only thing
> having a callback provides is the association between the rpmsg_device and the
> rpmsg_endpoint[1] that happens in rpmsg_dev_probe().  The QC folks already do
> this association in their platform code[2].  Since this is not done in
> __rpmsg_create_ept() a check for rpdev->ept == NULL could be done in
> rpmsg_eptdev_open() and do the assignment there. 
> 
> [1]. https://elixir.bootlin.com/linux/v5.12-rc6/source/drivers/rpmsg/rpmsg_core.c#L513  
> [2]. https://elixir.bootlin.com/linux/v5.12-rc6/source/drivers/rpmsg/qcom_glink_native.c#L1623
> 

That's a good point! When I started the redesign, I faced some issues with the
approach you propose. But as I can not remember the reason and because the code
has evolved, i need to re-think about this.

Thanks,
Arnaud


>> +	.drv = {
>> +		.name = "rpmsg_chrdev",
>> +	},
>> +};
>> +
>>  static int rpmsg_chrdev_init(void)
>>  {
>>  	int ret;
>>  
>>  	ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg_char");
>> -	if (ret < 0)
>> +	if (ret < 0) {
>>  		pr_err("rpmsg: failed to allocate char dev region\n");
>> +		return ret;
>> +	}
>> +
>> +	ret = register_rpmsg_driver(&rpmsg_chrdev_driver);
>> +	if (ret < 0) {
>> +		pr_err("rpmsg: failed to register rpmsg raw driver\n");
>> +		unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
>> +	}
>>  
>>  	return ret;
>>  }
>> @@ -417,6 +473,7 @@ 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);
>> -- 
>> 2.17.1
>>

Re: [PATCH v2 1/7] rpmsg: char: Export eptdev create an destroy functions

[Mathieu Poirier]

On Thu, Apr 22, 2021 at 09:55:47AM +0200, Arnaud POULIQUEN wrote:
> hello Mathieu
> 
> On 4/21/21 7:52 PM, Mathieu Poirier wrote:
> > On Tue, Apr 13, 2021 at 03:44:52PM +0200, Arnaud Pouliquen wrote:
> >> To prepare the split of the code related to the control (ctrldev)
> >> and the endpoint (eptdev) devices in 2 separate files:
> >>
> >> - Rename and export the functions in rpmsg_char.h.
> >>
> >> - Suppress the dependency with the rpmsg_ctrldev struct in the
> >>   rpmsg_chrdev_create_eptdev function.
> >>
> >> - The rpmsg class is provided as parameter in rpmsg_chrdev_create_eptdev,
> >>   because the class is associated to the control part.
> >>
> >> Suggested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> >> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
> >> ---
> >>  drivers/rpmsg/rpmsg_char.c | 19 +++++++++------
> >>  drivers/rpmsg/rpmsg_char.h | 50 ++++++++++++++++++++++++++++++++++++++
> >>  2 files changed, 61 insertions(+), 8 deletions(-)
> >>  create mode 100644 drivers/rpmsg/rpmsg_char.h
> >>
> >> diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
> >> index 2bebc9b2d163..b9df8dc4365f 100644
> >> --- a/drivers/rpmsg/rpmsg_char.c
> >> +++ b/drivers/rpmsg/rpmsg_char.c
> >> @@ -1,5 +1,6 @@
> >>  // SPDX-License-Identifier: GPL-2.0
> >>  /*
> >> + * Copyright (C) 2021, STMicroelectronics
> >>   * Copyright (c) 2016, Linaro Ltd.
> >>   * Copyright (c) 2012, Michal Simek <monstr@monstr.eu>
> >>   * Copyright (c) 2012, PetaLogix
> >> @@ -22,6 +23,7 @@
> >>  #include <linux/uaccess.h>
> >>  #include <uapi/linux/rpmsg.h>
> >>  
> >> +#include "rpmsg_char.h"
> >>  #include "rpmsg_internal.h"
> >>  
> >>  #define RPMSG_DEV_MAX	(MINORMASK + 1)
> >> @@ -78,7 +80,7 @@ struct rpmsg_eptdev {
> >>  	wait_queue_head_t readq;
> >>  };
> >>  
> >> -static int rpmsg_eptdev_destroy(struct device *dev, void *data)
> >> +int rpmsg_chrdev_destroy_eptdev(struct device *dev, void *data)
> > 
> > Shouldn't this be rpmsg_chrdev_eptdev_destroy()?  I've been wondering about the
> > flipping of destroy and eptdev...  The same for rpmsg_chrdev_create_eptdev().
> 
> As the function is exported i prefered to follow name srtructure that is
> commonly used: <module>_<action>_<object>
> 
> But it is not a rule, so please just tell me if you prefer that i rename the
> functions  rpmsg_chrdev_eptdev_xxxx?

I'd prefer rpmsg_chrdev_eptdev_create/destroy() since we are already familiar
with that terminology.

> 
> Thanks,
> Arnaud
> 
> > 
> > With that:
> > 
> > Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> > 
> >>  {
> >>  	struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);
> >>  
> >> @@ -97,6 +99,7 @@ static int rpmsg_eptdev_destroy(struct device *dev, void *data)
> >>  
> >>  	return 0;
> >>  }
> >> +EXPORT_SYMBOL(rpmsg_chrdev_destroy_eptdev);
> >>  
> >>  static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len,
> >>  			void *priv, u32 addr)
> >> @@ -280,7 +283,7 @@ static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
> >>  	if (cmd != RPMSG_DESTROY_EPT_IOCTL)
> >>  		return -EINVAL;
> >>  
> >> -	return rpmsg_eptdev_destroy(&eptdev->dev, NULL);
> >> +	return rpmsg_chrdev_destroy_eptdev(&eptdev->dev, NULL);
> >>  }
> >>  
> >>  static const struct file_operations rpmsg_eptdev_fops = {
> >> @@ -339,10 +342,9 @@ static void rpmsg_eptdev_release_device(struct device *dev)
> >>  	kfree(eptdev);
> >>  }
> >>  
> >> -static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev,
> >> -			       struct rpmsg_channel_info chinfo)
> >> +int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent,
> >> +			       struct rpmsg_channel_info chinfo, struct class *rpmsg_class)
> >>  {
> >> -	struct rpmsg_device *rpdev = ctrldev->rpdev;
> >>  	struct rpmsg_eptdev *eptdev;
> >>  	struct device *dev;
> >>  	int ret;
> >> @@ -362,7 +364,7 @@ static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev,
> >>  
> >>  	device_initialize(dev);
> >>  	dev->class = rpmsg_class;
> >> -	dev->parent = &ctrldev->dev;
> >> +	dev->parent = parent;
> >>  	dev->groups = rpmsg_eptdev_groups;
> >>  	dev_set_drvdata(dev, eptdev);
> >>  
> >> @@ -405,6 +407,7 @@ static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev,
> >>  
> >>  	return ret;
> >>  }
> >> +EXPORT_SYMBOL(rpmsg_chrdev_create_eptdev);
> >>  
> >>  static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp)
> >>  {
> >> @@ -444,7 +447,7 @@ static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
> >>  	chinfo.src = eptinfo.src;
> >>  	chinfo.dst = eptinfo.dst;
> >>  
> >> -	return rpmsg_eptdev_create(ctrldev, chinfo);
> >> +	return rpmsg_chrdev_create_eptdev(ctrldev->rpdev, &ctrldev->dev, chinfo, rpmsg_class);
> >>  };
> >>  
> >>  static const struct file_operations rpmsg_ctrldev_fops = {
> >> @@ -530,7 +533,7 @@ static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
> >>  	int ret;
> >>  
> >>  	/* Destroy all endpoints */
> >> -	ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_eptdev_destroy);
> >> +	ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_chrdev_destroy_eptdev);
> >>  	if (ret)
> >>  		dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret);
> >>  
> >> diff --git a/drivers/rpmsg/rpmsg_char.h b/drivers/rpmsg/rpmsg_char.h
> >> new file mode 100644
> >> index 000000000000..379d2ae2bee8
> >> --- /dev/null
> >> +++ b/drivers/rpmsg/rpmsg_char.h
> >> @@ -0,0 +1,50 @@
> >> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> >> +/*
> >> + * Copyright (C) STMicroelectronics 2021.
> >> + */
> >> +
> >> +#ifndef __RPMSG_CHRDEV_H__
> >> +#define __RPMSG_CHRDEV_H__
> >> +
> >> +#if IS_REACHABLE(CONFIG_RPMSG_CHAR)
> >> +/**
> >> + * rpmsg_chrdev_create_eptdev() - register char device based on an endpoint
> >> + * @rpdev:  prepared rpdev to be used for creating endpoints
> >> + * @parent: parent device
> >> + * @chinfo: assiated endpoint channel information.
> >> + *
> >> + * This function create a new rpmsg char endpoint device to instantiate a new
> >> + * endpoint based on chinfo information.
> >> + */
> >> +int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent,
> >> +			       struct rpmsg_channel_info chinfo, struct class *rpmsg_class);
> >> +
> >> +/**
> >> + * rpmsg_chrdev_destroy_eptdev() - destroy created char device endpoint.
> >> + * @data: private data associated to the endpoint device
> >> + *
> >> + * This function destroys a rpmsg char endpoint device created by the RPMSG_DESTROY_EPT_IOCTL
> >> + * control.
> >> + */
> >> +int rpmsg_chrdev_destroy_eptdev(struct device *dev, void *data);
> >> +
> >> +#else  /*IS_REACHABLE(CONFIG_RPMSG_CHAR) */
> >> +
> >> +static inline int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent,
> >> +					     struct rpmsg_channel_info chinfo,
> >> +					     struct class *rpmsg_class)
> >> +{
> >> +	return -EINVAL;
> >> +}
> >> +
> >> +static inline int rpmsg_chrdev_destroy_eptdev(struct device *dev, void *data)
> >> +{
> >> +	/* This shouldn't be possible */
> >> +	WARN_ON(1);
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +#endif /*IS_REACHABLE(CONFIG_RPMSG_CHAR) */
> >> +
> >> +#endif /*__RPMSG_CHRDEV_H__ */
> >> -- 
> >> 2.17.1
> >>

Re: [PATCH v2 2/7] rpmsg: Move the rpmsg control device from rpmsg_char to rpmsg_ctrl

[Mathieu Poirier]

On Thu, Apr 22, 2021 at 09:56:41AM +0200, Arnaud POULIQUEN wrote:
> 
> 
> On 4/21/21 8:04 PM, Mathieu Poirier wrote:
> > On Tue, Apr 13, 2021 at 03:44:53PM +0200, Arnaud Pouliquen wrote:
> >> Create the rpmsg_ctrl.c module and move the code related to the
> >> rpmsg_ctrldev device in this new module.
> >>
> >> Add the dependency between rpmsg_char and rpmsg_ctrl in the
> >> kconfig file.
> >>
> >> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
> >> ---
> >> update from v1:
> >> - keep "rpmsg_chrdev" driver name in rpmsg_ctrl, driver will be renamed
> >>   in next path that renames the rpmsg_chrdev_create_eptdev.
> >> - rename the chardev regions
> >> - move RPMSG_DEV_MAX to rpmsg_char.h
> >> ---
> >>  drivers/rpmsg/Kconfig      |   9 ++
> >>  drivers/rpmsg/Makefile     |   1 +
> >>  drivers/rpmsg/rpmsg_char.c | 181 +----------------------------
> >>  drivers/rpmsg/rpmsg_char.h |   2 +
> >>  drivers/rpmsg/rpmsg_ctrl.c | 231 +++++++++++++++++++++++++++++++++++++
> >>  5 files changed, 245 insertions(+), 179 deletions(-)
> >>  create mode 100644 drivers/rpmsg/rpmsg_ctrl.c
> >>
> >> diff --git a/drivers/rpmsg/Kconfig b/drivers/rpmsg/Kconfig
> >> index 0b4407abdf13..d822ec9ec692 100644
> >> --- a/drivers/rpmsg/Kconfig
> 
> snip[...]
> 
> >> +static int rpmsg_ctrldev_init(void)
> >> +{
> >> +	int ret;
> >> +
> >> +	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");
> >> +		return ret;
> >> +	}
> >> +
> >> +	rpmsg_class = class_create(THIS_MODULE, "rpmsg");
> > 
> > This class thing really bothers me.  Keeping this here means that rpmsg_eptdevs
> > created from user space will be associated to this rpmsg_class but those created
> > from the name service won't.  As such I propose to move this to rpmsg_char and
> > simply not associate the control device to the class.
> > 
> > Otherwise we'd have to introduce some mechanic only to deal with the creation of
> > the class and I don't think it is worth.  We can revise that approach if someone
> > complains we broke their user space. 
> 
> I agree with that as it was my first proposed approach here [1]

Yeah, sorry about that.  This patch review process is not an exact science...

> 
> [1] https://www.spinics.net/lists/linux-arm-msm/msg81194.html
> 
> Thanks,
> Arnaud
> 
> > 
> > 
> >> +	if (IS_ERR(rpmsg_class)) {
> >> +		pr_err("failed to create rpmsg class\n");
> >> +		ret = PTR_ERR(rpmsg_class);
> >> +		goto free_region;
> >> +	}
> >> +
> >> +	ret = register_rpmsg_driver(&rpmsg_ctrldev_driver);
> >> +	if (ret < 0) {
> >> +		pr_err("rpmsg ctrl: failed to register rpmsg driver\n");
> >> +		goto free_class;
> >> +	}
> >> +
> >> +	return 0;
> >> +
> >> +free_class:
> >> +	class_destroy(rpmsg_class);
> >> +free_region:
> >> +	unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
> >> +
> >> +	return ret;
> >> +}
> >> +postcore_initcall(rpmsg_ctrldev_init);
> >> +
> >> +static void rpmsg_ctrldev_exit(void)
> >> +{
> >> +	unregister_rpmsg_driver(&rpmsg_ctrldev_driver);
> >> +	class_destroy(rpmsg_class);
> >> +	unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
> >> +}
> >> +module_exit(rpmsg_ctrldev_exit);
> >> +
> >> +MODULE_DESCRIPTION("rpmsg control interface");
> >> +MODULE_ALIAS("rpmsg:" KBUILD_MODNAME);
> >> +MODULE_LICENSE("GPL v2");
> >> -- 
> >> 2.17.1
> >>

Re: [PATCH v2 5/7] rpmsg: char: Introduce a rpmsg driver for the rpmsg char device

[Mathieu Poirier]

On Thu, Apr 22, 2021 at 09:58:27AM +0200, Arnaud POULIQUEN wrote:
> On 4/21/21 7:40 PM, Mathieu Poirier wrote:
> > Good day Arnaud,
> > 
> > On Tue, Apr 13, 2021 at 03:44:56PM +0200, Arnaud Pouliquen wrote:
> >> A rpmsg char device allows to probe the endpoint device on a remote name
> >> service announcement.
> >>
> >> With this patch the /dev/rpmsgX interface is created either by a user
> >> application or by the remote firmware.
> >>
> >> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
> >>
> >> ---
> >> update from V1:
> >>  - add missing unregister_rpmsg_driver call on module exit.
> >>
> >> ---
> >>  drivers/rpmsg/rpmsg_char.c | 59 +++++++++++++++++++++++++++++++++++++-
> >>  1 file changed, 58 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
> >> index a64249d83172..4606787b7011 100644
> >> --- a/drivers/rpmsg/rpmsg_char.c
> >> +++ b/drivers/rpmsg/rpmsg_char.c
> >> @@ -26,6 +26,8 @@
> >>  #include "rpmsg_char.h"
> >>  #include "rpmsg_internal.h"
> >>  
> >> +#define RPMSG_CHAR_DEVNAME "rpmsg-raw"
> >> +
> > 
> > Why not simply call it rpmsg-char?
> 
> I would avoid to link the rpmsg name service to the Linux Kernel device.

To me that's exactly what we want to do...  Am I missing something?

> 
> > 
> >>  static dev_t rpmsg_major;
> >>  
> >>  static DEFINE_IDA(rpmsg_ept_ida);
> >> @@ -403,13 +405,67 @@ int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent
> >>  }
> >>  EXPORT_SYMBOL(rpmsg_chrdev_create_eptdev);
> >>  
> >> +static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev)
> >> +{
> >> +	struct rpmsg_channel_info chinfo;
> >> +	struct rpmsg_eptdev *eptdev;
> >> +
> >> +	if (!rpdev->ept)
> >> +		return -EINVAL;
> >> +
> >> +	memcpy(chinfo.name, RPMSG_CHAR_DEVNAME, sizeof(RPMSG_CHAR_DEVNAME));
> >> +	chinfo.src = rpdev->src;
> >> +	chinfo.dst = rpdev->dst;
> >> +
> >> +	eptdev = __rpmsg_chrdev_create_eptdev(rpdev, &rpdev->dev, chinfo, NULL);
> >> +	if (IS_ERR(eptdev))
> >> +		return PTR_ERR(eptdev);
> >> +
> >> +	/* Set the private field of the default endpoint to retrieve context on callback. */
> >> +	rpdev->ept->priv = eptdev;
> > 
> > This is already done in rpmsg_create_ept() when rpmsg_eptdev_open() is called.
> > 
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
> >> +{
> >> +	int ret;
> >> +
> >> +	ret = device_for_each_child(&rpdev->dev, NULL, rpmsg_chrdev_destroy_eptdev);
> >> +	if (ret)
> >> +		dev_warn(&rpdev->dev, "failed to destroy endpoints: %d\n", ret);
> >> +}
> >> +
> >> +static struct rpmsg_device_id rpmsg_chrdev_id_table[] = {
> >> +	{ .name	= RPMSG_CHAR_DEVNAME },
> >> +	{ },
> >> +};
> >> +
> >> +static struct rpmsg_driver rpmsg_chrdev_driver = {
> >> +	.probe = rpmsg_chrdev_probe,
> >> +	.remove = rpmsg_chrdev_remove,
> >> +	.id_table = rpmsg_chrdev_id_table,
> >> +	.callback = rpmsg_ept_cb,
> > 
> > Not sure why we need a callback associated to this driver when
> > rpmsg_eptdev_open() already creates and rpmsg_endpoint.  To me the only thing
> > having a callback provides is the association between the rpmsg_device and the
> > rpmsg_endpoint[1] that happens in rpmsg_dev_probe().  The QC folks already do
> > this association in their platform code[2].  Since this is not done in
> > __rpmsg_create_ept() a check for rpdev->ept == NULL could be done in
> > rpmsg_eptdev_open() and do the assignment there. 
> > 
> > [1]. https://elixir.bootlin.com/linux/v5.12-rc6/source/drivers/rpmsg/rpmsg_core.c#L513  
> > [2]. https://elixir.bootlin.com/linux/v5.12-rc6/source/drivers/rpmsg/qcom_glink_native.c#L1623
> > 
> 
> That's a good point! When I started the redesign, I faced some issues with the
> approach you propose. But as I can not remember the reason and because the code
> has evolved, i need to re-think about this.
> 

Glad to see we're on the same page.  I stared at this code for a very long time,
thinking there was some kind of bigger picture I wasn't getting.


> Thanks,
> Arnaud
> 
> 
> >> +	.drv = {
> >> +		.name = "rpmsg_chrdev",
> >> +	},
> >> +};
> >> +
> >>  static int rpmsg_chrdev_init(void)
> >>  {
> >>  	int ret;
> >>  
> >>  	ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg_char");
> >> -	if (ret < 0)
> >> +	if (ret < 0) {
> >>  		pr_err("rpmsg: failed to allocate char dev region\n");
> >> +		return ret;
> >> +	}
> >> +
> >> +	ret = register_rpmsg_driver(&rpmsg_chrdev_driver);
> >> +	if (ret < 0) {
> >> +		pr_err("rpmsg: failed to register rpmsg raw driver\n");
> >> +		unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
> >> +	}
> >>  
> >>  	return ret;
> >>  }
> >> @@ -417,6 +473,7 @@ 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);
> >> -- 
> >> 2.17.1
> >>

Re: [PATCH v2 2/7] rpmsg: Move the rpmsg control device from rpmsg_char to rpmsg_ctrl

[Arnaud POULIQUEN]

On 4/22/21 6:32 PM, Mathieu Poirier wrote:
> On Thu, Apr 22, 2021 at 09:56:41AM +0200, Arnaud POULIQUEN wrote:
>>
>>
>> On 4/21/21 8:04 PM, Mathieu Poirier wrote:
>>> On Tue, Apr 13, 2021 at 03:44:53PM +0200, Arnaud Pouliquen wrote:
>>>> Create the rpmsg_ctrl.c module and move the code related to the
>>>> rpmsg_ctrldev device in this new module.
>>>>
>>>> Add the dependency between rpmsg_char and rpmsg_ctrl in the
>>>> kconfig file.
>>>>
>>>> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
>>>> ---
>>>> update from v1:
>>>> - keep "rpmsg_chrdev" driver name in rpmsg_ctrl, driver will be renamed
>>>>   in next path that renames the rpmsg_chrdev_create_eptdev.
>>>> - rename the chardev regions
>>>> - move RPMSG_DEV_MAX to rpmsg_char.h
>>>> ---
>>>>  drivers/rpmsg/Kconfig      |   9 ++
>>>>  drivers/rpmsg/Makefile     |   1 +
>>>>  drivers/rpmsg/rpmsg_char.c | 181 +----------------------------
>>>>  drivers/rpmsg/rpmsg_char.h |   2 +
>>>>  drivers/rpmsg/rpmsg_ctrl.c | 231 +++++++++++++++++++++++++++++++++++++
>>>>  5 files changed, 245 insertions(+), 179 deletions(-)
>>>>  create mode 100644 drivers/rpmsg/rpmsg_ctrl.c
>>>>
>>>> diff --git a/drivers/rpmsg/Kconfig b/drivers/rpmsg/Kconfig
>>>> index 0b4407abdf13..d822ec9ec692 100644
>>>> --- a/drivers/rpmsg/Kconfig
>>
>> snip[...]
>>
>>>> +static int rpmsg_ctrldev_init(void)
>>>> +{
>>>> +	int ret;
>>>> +
>>>> +	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");
>>>> +		return ret;
>>>> +	}
>>>> +
>>>> +	rpmsg_class = class_create(THIS_MODULE, "rpmsg");
>>>
>>> This class thing really bothers me.  Keeping this here means that rpmsg_eptdevs
>>> created from user space will be associated to this rpmsg_class but those created
>>> from the name service won't.  As such I propose to move this to rpmsg_char and
>>> simply not associate the control device to the class.
>>>
>>> Otherwise we'd have to introduce some mechanic only to deal with the creation of
>>> the class and I don't think it is worth.  We can revise that approach if someone
>>> complains we broke their user space. 
>>
>> I agree with that as it was my first proposed approach here [1]
> 
> Yeah, sorry about that.  This patch review process is not an exact science...

No worries, exploring alternatives is part of the upstream process  :)

> 
>>
>> [1] https://www.spinics.net/lists/linux-arm-msm/msg81194.html
>>
>> Thanks,
>> Arnaud
>>
>>>
>>>
>>>> +	if (IS_ERR(rpmsg_class)) {
>>>> +		pr_err("failed to create rpmsg class\n");
>>>> +		ret = PTR_ERR(rpmsg_class);
>>>> +		goto free_region;
>>>> +	}
>>>> +
>>>> +	ret = register_rpmsg_driver(&rpmsg_ctrldev_driver);
>>>> +	if (ret < 0) {
>>>> +		pr_err("rpmsg ctrl: failed to register rpmsg driver\n");
>>>> +		goto free_class;
>>>> +	}
>>>> +
>>>> +	return 0;
>>>> +
>>>> +free_class:
>>>> +	class_destroy(rpmsg_class);
>>>> +free_region:
>>>> +	unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
>>>> +
>>>> +	return ret;
>>>> +}
>>>> +postcore_initcall(rpmsg_ctrldev_init);
>>>> +
>>>> +static void rpmsg_ctrldev_exit(void)
>>>> +{
>>>> +	unregister_rpmsg_driver(&rpmsg_ctrldev_driver);
>>>> +	class_destroy(rpmsg_class);
>>>> +	unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
>>>> +}
>>>> +module_exit(rpmsg_ctrldev_exit);
>>>> +
>>>> +MODULE_DESCRIPTION("rpmsg control interface");
>>>> +MODULE_ALIAS("rpmsg:" KBUILD_MODNAME);
>>>> +MODULE_LICENSE("GPL v2");
>>>> -- 
>>>> 2.17.1
>>>>

Re: [PATCH v2 5/7] rpmsg: char: Introduce a rpmsg driver for the rpmsg char device

[Arnaud POULIQUEN]

On 4/22/21 6:36 PM, Mathieu Poirier wrote:
> On Thu, Apr 22, 2021 at 09:58:27AM +0200, Arnaud POULIQUEN wrote:
>> On 4/21/21 7:40 PM, Mathieu Poirier wrote:
>>> Good day Arnaud,
>>>
>>> On Tue, Apr 13, 2021 at 03:44:56PM +0200, Arnaud Pouliquen wrote:
>>>> A rpmsg char device allows to probe the endpoint device on a remote name
>>>> service announcement.
>>>>
>>>> With this patch the /dev/rpmsgX interface is created either by a user
>>>> application or by the remote firmware.
>>>>
>>>> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
>>>>
>>>> ---
>>>> update from V1:
>>>>  - add missing unregister_rpmsg_driver call on module exit.
>>>>
>>>> ---
>>>>  drivers/rpmsg/rpmsg_char.c | 59 +++++++++++++++++++++++++++++++++++++-
>>>>  1 file changed, 58 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
>>>> index a64249d83172..4606787b7011 100644
>>>> --- a/drivers/rpmsg/rpmsg_char.c
>>>> +++ b/drivers/rpmsg/rpmsg_char.c
>>>> @@ -26,6 +26,8 @@
>>>>  #include "rpmsg_char.h"
>>>>  #include "rpmsg_internal.h"
>>>>  
>>>> +#define RPMSG_CHAR_DEVNAME "rpmsg-raw"
>>>> +
>>>
>>> Why not simply call it rpmsg-char?
>>
>> I would avoid to link the rpmsg name service to the Linux Kernel device.
> 
> To me that's exactly what we want to do...  Am I missing something?

A discussion started about a service layer in the OpenAMP library.
"rpmsg-char" doesn't really make sense in OpenAMP, especially for
OpenAMP<->openAMP communication.

That's why I think a generic name would be more suitable.

Regards,
Arnaud

> 
>>
>>>
>>>>  static dev_t rpmsg_major;
>>>>  
>>>>  static DEFINE_IDA(rpmsg_ept_ida);
>>>> @@ -403,13 +405,67 @@ int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent
>>>>  }
>>>>  EXPORT_SYMBOL(rpmsg_chrdev_create_eptdev);
>>>>  
>>>> +static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev)
>>>> +{
>>>> +	struct rpmsg_channel_info chinfo;
>>>> +	struct rpmsg_eptdev *eptdev;
>>>> +
>>>> +	if (!rpdev->ept)
>>>> +		return -EINVAL;
>>>> +
>>>> +	memcpy(chinfo.name, RPMSG_CHAR_DEVNAME, sizeof(RPMSG_CHAR_DEVNAME));
>>>> +	chinfo.src = rpdev->src;
>>>> +	chinfo.dst = rpdev->dst;
>>>> +
>>>> +	eptdev = __rpmsg_chrdev_create_eptdev(rpdev, &rpdev->dev, chinfo, NULL);
>>>> +	if (IS_ERR(eptdev))
>>>> +		return PTR_ERR(eptdev);
>>>> +
>>>> +	/* Set the private field of the default endpoint to retrieve context on callback. */
>>>> +	rpdev->ept->priv = eptdev;
>>>
>>> This is already done in rpmsg_create_ept() when rpmsg_eptdev_open() is called.
>>>
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
>>>> +{
>>>> +	int ret;
>>>> +
>>>> +	ret = device_for_each_child(&rpdev->dev, NULL, rpmsg_chrdev_destroy_eptdev);
>>>> +	if (ret)
>>>> +		dev_warn(&rpdev->dev, "failed to destroy endpoints: %d\n", ret);
>>>> +}
>>>> +
>>>> +static struct rpmsg_device_id rpmsg_chrdev_id_table[] = {
>>>> +	{ .name	= RPMSG_CHAR_DEVNAME },
>>>> +	{ },
>>>> +};
>>>> +
>>>> +static struct rpmsg_driver rpmsg_chrdev_driver = {
>>>> +	.probe = rpmsg_chrdev_probe,
>>>> +	.remove = rpmsg_chrdev_remove,
>>>> +	.id_table = rpmsg_chrdev_id_table,
>>>> +	.callback = rpmsg_ept_cb,
>>>
>>> Not sure why we need a callback associated to this driver when
>>> rpmsg_eptdev_open() already creates and rpmsg_endpoint.  To me the only thing
>>> having a callback provides is the association between the rpmsg_device and the
>>> rpmsg_endpoint[1] that happens in rpmsg_dev_probe().  The QC folks already do
>>> this association in their platform code[2].  Since this is not done in
>>> __rpmsg_create_ept() a check for rpdev->ept == NULL could be done in
>>> rpmsg_eptdev_open() and do the assignment there. 
>>>
>>> [1]. https://elixir.bootlin.com/linux/v5.12-rc6/source/drivers/rpmsg/rpmsg_core.c#L513  
>>> [2]. https://elixir.bootlin.com/linux/v5.12-rc6/source/drivers/rpmsg/qcom_glink_native.c#L1623
>>>
>>
>> That's a good point! When I started the redesign, I faced some issues with the
>> approach you propose. But as I can not remember the reason and because the code
>> has evolved, i need to re-think about this.
>>
> 
> Glad to see we're on the same page.  I stared at this code for a very long time,
> thinking there was some kind of bigger picture I wasn't getting.
> 
> 
>> Thanks,
>> Arnaud
>>
>>
>>>> +	.drv = {
>>>> +		.name = "rpmsg_chrdev",
>>>> +	},
>>>> +};
>>>> +
>>>>  static int rpmsg_chrdev_init(void)
>>>>  {
>>>>  	int ret;
>>>>  
>>>>  	ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg_char");
>>>> -	if (ret < 0)
>>>> +	if (ret < 0) {
>>>>  		pr_err("rpmsg: failed to allocate char dev region\n");
>>>> +		return ret;
>>>> +	}
>>>> +
>>>> +	ret = register_rpmsg_driver(&rpmsg_chrdev_driver);
>>>> +	if (ret < 0) {
>>>> +		pr_err("rpmsg: failed to register rpmsg raw driver\n");
>>>> +		unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
>>>> +	}
>>>>  
>>>>  	return ret;
>>>>  }
>>>> @@ -417,6 +473,7 @@ 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);
>>>> -- 
>>>> 2.17.1
>>>>

Re: [PATCH v2 5/7] rpmsg: char: Introduce a rpmsg driver for the rpmsg char device

[Arnaud POULIQUEN]

Hi,

On 4/22/21 6:36 PM, Mathieu Poirier wrote:
> On Thu, Apr 22, 2021 at 09:58:27AM +0200, Arnaud POULIQUEN wrote:
>> On 4/21/21 7:40 PM, Mathieu Poirier wrote:
>>> Good day Arnaud,
>>>
>>> On Tue, Apr 13, 2021 at 03:44:56PM +0200, Arnaud Pouliquen wrote:
>>>> A rpmsg char device allows to probe the endpoint device on a remote name
>>>> service announcement.
>>>>
>>>> With this patch the /dev/rpmsgX interface is created either by a user
>>>> application or by the remote firmware.
>>>>
>>>> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
>>>>
>>>> ---
>>>> update from V1:
>>>>  - add missing unregister_rpmsg_driver call on module exit.
>>>>
>>>> ---
>>>>  drivers/rpmsg/rpmsg_char.c | 59 +++++++++++++++++++++++++++++++++++++-
>>>>  1 file changed, 58 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
>>>> index a64249d83172..4606787b7011 100644
>>>> --- a/drivers/rpmsg/rpmsg_char.c
>>>> +++ b/drivers/rpmsg/rpmsg_char.c
>>>> @@ -26,6 +26,8 @@
>>>>  #include "rpmsg_char.h"
>>>>  #include "rpmsg_internal.h"
>>>>  
>>>> +#define RPMSG_CHAR_DEVNAME "rpmsg-raw"
>>>> +
>>>
>>> Why not simply call it rpmsg-char?
>>
>> I would avoid to link the rpmsg name service to the Linux Kernel device.
> 
> To me that's exactly what we want to do...  Am I missing something?
> 
>>
>>>
>>>>  static dev_t rpmsg_major;
>>>>  
>>>>  static DEFINE_IDA(rpmsg_ept_ida);
>>>> @@ -403,13 +405,67 @@ int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent
>>>>  }
>>>>  EXPORT_SYMBOL(rpmsg_chrdev_create_eptdev);
>>>>  
>>>> +static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev)
>>>> +{
>>>> +	struct rpmsg_channel_info chinfo;
>>>> +	struct rpmsg_eptdev *eptdev;
>>>> +
>>>> +	if (!rpdev->ept)
>>>> +		return -EINVAL;
>>>> +
>>>> +	memcpy(chinfo.name, RPMSG_CHAR_DEVNAME, sizeof(RPMSG_CHAR_DEVNAME));
>>>> +	chinfo.src = rpdev->src;
>>>> +	chinfo.dst = rpdev->dst;
>>>> +
>>>> +	eptdev = __rpmsg_chrdev_create_eptdev(rpdev, &rpdev->dev, chinfo, NULL);
>>>> +	if (IS_ERR(eptdev))
>>>> +		return PTR_ERR(eptdev);
>>>> +
>>>> +	/* Set the private field of the default endpoint to retrieve context on callback. */
>>>> +	rpdev->ept->priv = eptdev;
>>>
>>> This is already done in rpmsg_create_ept() when rpmsg_eptdev_open() is called.
>>>
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
>>>> +{
>>>> +	int ret;
>>>> +
>>>> +	ret = device_for_each_child(&rpdev->dev, NULL, rpmsg_chrdev_destroy_eptdev);
>>>> +	if (ret)
>>>> +		dev_warn(&rpdev->dev, "failed to destroy endpoints: %d\n", ret);
>>>> +}
>>>> +
>>>> +static struct rpmsg_device_id rpmsg_chrdev_id_table[] = {
>>>> +	{ .name	= RPMSG_CHAR_DEVNAME },
>>>> +	{ },
>>>> +};
>>>> +
>>>> +static struct rpmsg_driver rpmsg_chrdev_driver = {
>>>> +	.probe = rpmsg_chrdev_probe,
>>>> +	.remove = rpmsg_chrdev_remove,
>>>> +	.id_table = rpmsg_chrdev_id_table,
>>>> +	.callback = rpmsg_ept_cb,
>>>
>>> Not sure why we need a callback associated to this driver when
>>> rpmsg_eptdev_open() already creates and rpmsg_endpoint.  To me the only thing
>>> having a callback provides is the association between the rpmsg_device and the
>>> rpmsg_endpoint[1] that happens in rpmsg_dev_probe().  The QC folks already do
>>> this association in their platform code[2].  Since this is not done in
>>> __rpmsg_create_ept() a check for rpdev->ept == NULL could be done in
>>> rpmsg_eptdev_open() and do the assignment there. 
>>>
>>> [1]. https://elixir.bootlin.com/linux/v5.12-rc6/source/drivers/rpmsg/rpmsg_core.c#L513  
>>> [2]. https://elixir.bootlin.com/linux/v5.12-rc6/source/drivers/rpmsg/qcom_glink_native.c#L1623
>>>
>>
>> That's a good point! When I started the redesign, I faced some issues with the
>> approach you propose. But as I can not remember the reason and because the code
>> has evolved, i need to re-think about this.
>>
> 
> Glad to see we're on the same page.  I stared at this code for a very long time,
> thinking there was some kind of bigger picture I wasn't getting.

I finally found the time to investigate this. If I remember now why I used this
approach, I also saw that my patchset does not work with the QCOM platform driver.

As a first step of explanation, let's ignore the QC platform.
rpdev->ept is null for the rpmsg ctrldev device created by the virtio rpmsg bus.
If no default endpoint is created on rpmsg_chrdev_probe, it is not possible to
differentiate the two in rpmsg_eptdev_open based on rpdev->ept == NULL.

Now let's add the QC implementation
As you mentioned, QC sets the rpdev->ept to a default endpoint before
registering the rpmsg ctrldev. This shows that it is not reasonable to expect to
handle all use cases based on the rpdev->ept value.

So, to summarize, I need to rework this, probably by adding a new field in the
rpmsg_eptdev structure, to properly handle the endpoint creation in the
rpmsg_eptdev_open function.

Regards,
Arnaud

> 
> 
>> Thanks,
>> Arnaud
>>
>>
>>>> +	.drv = {
>>>> +		.name = "rpmsg_chrdev",
>>>> +	},
>>>> +};
>>>> +
>>>>  static int rpmsg_chrdev_init(void)
>>>>  {
>>>>  	int ret;
>>>>  
>>>>  	ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg_char");
>>>> -	if (ret < 0)
>>>> +	if (ret < 0) {
>>>>  		pr_err("rpmsg: failed to allocate char dev region\n");
>>>> +		return ret;
>>>> +	}
>>>> +
>>>> +	ret = register_rpmsg_driver(&rpmsg_chrdev_driver);
>>>> +	if (ret < 0) {
>>>> +		pr_err("rpmsg: failed to register rpmsg raw driver\n");
>>>> +		unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
>>>> +	}
>>>>  
>>>>  	return ret;
>>>>  }
>>>> @@ -417,6 +473,7 @@ 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);
>>>> -- 
>>>> 2.17.1
>>>>