Re: [PATCH v2 4/4] rpmsg: char: Introduce the "rpmsg-raw" channel

Mathieu Poirier
2021-06-30T20:53:10Z

On Wed, Jun 23, 2021 at 05:05:04PM +0200, Arnaud Pouliquen wrote:
> Allows to probe the endpoint device on a remote name service announcement,
> by registering a rpmsg_driverfor the "rpmsg-raw" channel.
>
> With this patch the /dev/rpmsgX interface can be instantiated by the remote
> firmware.
>
> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
> ---
> update vs V1:
> - management of the default endpoint creation in the driver probe.
>
> ---
> drivers/rpmsg/rpmsg_char.c | 75 +++++++++++++++++++++++++++++++++++++-
> 1 file changed, 73 insertions(+), 2 deletions(-)
>

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

> diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
> index a75dce1e29d8..3748de00c97b 100644
> --- a/drivers/rpmsg/rpmsg_char.c
> +++ b/drivers/rpmsg/rpmsg_char.c
> @@ -25,6 +25,8 @@
>
> #include "rpmsg_char.h"
>
> +#define RPMSG_CHAR_DEVNAME "rpmsg-raw"
> +
> static dev_t rpmsg_major;
> static struct class *rpmsg_class;
>
> @@ -421,6 +423,61 @@ int rpmsg_chrdev_eptdev_create(struct rpmsg_device *rpdev, struct device *parent
> }
> EXPORT_SYMBOL(rpmsg_chrdev_eptdev_create);
>
> +static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev)
> +{
> + struct rpmsg_channel_info chinfo;
> + struct rpmsg_eptdev *eptdev;
> + struct rpmsg_endpoint *ept;
> +
> + memcpy(chinfo.name, RPMSG_CHAR_DEVNAME, sizeof(RPMSG_CHAR_DEVNAME));
> + chinfo.src = rpdev->src;
> + chinfo.dst = rpdev->dst;
> +
> + eptdev = __rpmsg_chrdev_eptdev_create(rpdev, &rpdev->dev, chinfo);
> + if (IS_ERR(eptdev))
> + return PTR_ERR(eptdev);
> +
> + /*
> + * Create the default endpoint associated to the rpmsg device and provide rpmsg_eptdev
> + * structure as callback private data.
> + */
> + ept = rpmsg_create_default_ept(rpdev, rpmsg_ept_cb, eptdev, eptdev->chinfo);
> + if (!ept) {
> + dev_err(&rpdev->dev, "failed to create %s\n", eptdev->chinfo.name);
> + put_device(&eptdev->dev);
> + return -EINVAL;
> + }
> +
> + /*
> + * Do not allow the creation and release of an endpoint on /dev/rpmsgX open and close,
> + * reuse the default endpoint instead
> + */
> + eptdev->static_ept = true;
> +
> + return 0;
> +}
> +
> +static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
> +{
> + int ret;
> +
> + ret = device_for_each_child(&rpdev->dev, NULL, rpmsg_chrdev_eptdev_destroy);
> + if (ret)
> + dev_warn(&rpdev->dev, "failed to destroy endpoints: %d\n", ret);
> +}
> +
> +static struct rpmsg_device_id rpmsg_chrdev_id_table[] = {
> + { .name = RPMSG_CHAR_DEVNAME },
> + { },
> +};
> +
> +static struct rpmsg_driver rpmsg_chrdev_driver = {
> + .probe = rpmsg_chrdev_probe,
> + .remove = rpmsg_chrdev_remove,
> + .id_table = rpmsg_chrdev_id_table,
> + .drv.name = "rpmsg_chrdev",
> +};
> +
> static int rpmsg_chrdev_init(void)
> {
> int ret;
> @@ -434,16 +491,30 @@ static int rpmsg_chrdev_init(void)
> 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 = PTR_ERR(rpmsg_class);
> + goto free_region;
> + }
> +
> + ret = register_rpmsg_driver(&rpmsg_chrdev_driver);
> + if (ret < 0) {
> + pr_err("rpmsg: failed to register rpmsg raw 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_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);
> }
> --
> 2.17.1
>