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@xxxxxxxxxxx>
>
> ---
> 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
>
