Re: [PATCH v2 04/16] rpmsg: ctrl: implement the ioctl function to create device

Mathieu Poirier
2021-01-21T23:54:19Z

On Tue, Dec 22, 2020 at 11:57:14AM +0100, Arnaud Pouliquen wrote:
> Implement the ioctl function that parses the list of
> rpmsg drivers registered to create an associated device.
> To be ISO user API, in a first step, the driver_override
> is only allowed for the RPMsg raw service, supported by the
> rpmsg_char driver.
>
> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
> ---
> drivers/rpmsg/rpmsg_ctrl.c | 43 ++++++++++++++++++++++++++++++++++++--
> 1 file changed, 41 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/rpmsg/rpmsg_ctrl.c b/drivers/rpmsg/rpmsg_ctrl.c
> index 065e2e304019..8381b5b2b794 100644
> --- a/drivers/rpmsg/rpmsg_ctrl.c
> +++ b/drivers/rpmsg/rpmsg_ctrl.c
> @@ -56,12 +56,51 @@ static int rpmsg_ctrl_dev_open(struct inode *inode, struct file *filp)
> return 0;
> }
>
> +static const char *rpmsg_ctrl_get_drv_name(u32 service)
> +{
> + struct rpmsg_ctl_info *drv_info;
> +
> + list_for_each_entry(drv_info, &rpmsg_drv_list, node) {
> + if (drv_info->ctrl->service == service)
> + return drv_info->ctrl->drv_name;
> + }
> +

I'm unsure about the above... To me this looks like what the .match() function
of a bus would do. And when I read Bjorn's comment he brought up the
auxiliary_bus. I don't know about the auxiliary_bus but it is worth looking
into. Registering with a bus would streamline a lot of the code in this
patchset.

I'm out of time for today - I will continue tomorrow.

Thanks,
Mathieu

> + return NULL;
> +}
> +
> static long rpmsg_ctrl_dev_ioctl(struct file *fp, unsigned int cmd,
> unsigned long arg)
> {
> struct rpmsg_ctrl_dev *ctrldev = fp->private_data;
> -
> - dev_info(&ctrldev->dev, "Control not yet implemented\n");
> + void __user *argp = (void __user *)arg;
> + struct rpmsg_channel_info chinfo;
> + struct rpmsg_endpoint_info eptinfo;
> + struct rpmsg_device *newch;
> +
> + if (cmd != RPMSG_CREATE_EPT_IOCTL)
> + return -EINVAL;
> +
> + if (copy_from_user(&eptinfo, argp, sizeof(eptinfo)))
> + return -EFAULT;
> +
> + /*
> + * In a frst step only the rpmsg_raw service is supported.
> + * The override is foorced to RPMSG_RAW_SERVICE
> + */
> + chinfo.driver_override = rpmsg_ctrl_get_drv_name(RPMSG_RAW_SERVICE);
> + if (!chinfo.driver_override)
> + return -ENODEV;
> +
> + memcpy(chinfo.name, eptinfo.name, RPMSG_NAME_SIZE);
> + chinfo.name[RPMSG_NAME_SIZE - 1] = '\0';
> + chinfo.src = eptinfo.src;
> + chinfo.dst = eptinfo.dst;
> +
> + newch = rpmsg_create_channel(ctrldev->rpdev, &chinfo);
> + if (!newch) {
> + dev_err(&ctrldev->dev, "rpmsg_create_channel failed\n");
> + return -ENXIO;
> + }
>
> return 0;
> };
> --
> 2.17.1
>