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

From: Mathieu Poirier
Date: Fri Apr 09 2021 - 13:36:51 EST

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On Tue, Mar 23, 2021 at 01:27:32PM +0100, 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@xxxxxxxxxxx>
> ---
> update from [1]:
> - keep rpmsg_ctrldev prefix (no more functions and structures renaming),
>

That is much better

> [1]: https://patchwork.kernel.org/project/linux-remoteproc/patch/20210219111501.14261-7-arnaud.pouliquen@xxxxxxxxxxx/
> ---
> drivers/rpmsg/Kconfig | 9 ++
> drivers/rpmsg/Makefile | 1 +
> drivers/rpmsg/rpmsg_char.c | 177 +---------------------------
> drivers/rpmsg/rpmsg_ctrl.c | 233 +++++++++++++++++++++++++++++++++++++
> 4 files changed, 244 insertions(+), 176 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..5d4a768002ce 100644
> --- a/drivers/rpmsg/rpmsg_char.c
> +++ b/drivers/rpmsg/rpmsg_char.c
> @@ -29,30 +29,13 @@
> #define RPMSG_DEV_MAX (MINORMASK + 1)
>

That define is also present in rpmsg_ctrl.c. As such I would move it to
rpmsg_char.h.

> 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 +392,13 @@ 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");

To avoid any confusion I would put "rpmsg_char"... And I don't think it changes
anything for users.

> - if (ret < 0) {
> + 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 +406,6 @@ 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_ctrl.c b/drivers/rpmsg/rpmsg_ctrl.c
> new file mode 100644
> index 000000000000..e203ecc18120
> --- /dev/null
> +++ b/drivers/rpmsg/rpmsg_ctrl.c
> @@ -0,0 +1,233 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2021, STMicroelectronics
> + * Copyright (c) 2016, Linaro Ltd.
> + * Copyright (c) 2012, Michal Simek <monstr@xxxxxxxxx>
> + * 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"
> +
> +#define RPMSG_DEV_MAX (MINORMASK + 1)
> +
> +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_ctrl",

With this change rpmsg_chrdev_register_device() will fail to find a driver to
work with, something that will break the Glink/SMD code if someone tries a
bisect. Things will work out just fine if you move this to patch 3.

> + },
> +};
> +
> +static int rpmsg_ctrldev_init(void)
> +{
> + int ret;
> +
> + ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg");

And here I'd go with "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
>

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