On 12/7/22 14:04, Sarannya S wrote:
> Add TICOMGET and TIOCMSET ioctl support for rpmsg char device nodes
> to get/set the low level transport signals.
>
> Signed-off-by: Chris Lew <quic_clew@xxxxxxxxxxx>
> Signed-off-by: Deepak Kumar Singh <quic_deesin@xxxxxxxxxxx>
> Signed-off-by: Sarannya S <quic_sarannya@xxxxxxxxxxx>
> ---
> drivers/rpmsg/rpmsg_char.c | 60 +++++++++++++++++++++++++++++++++++++++-------
> 1 file changed, 52 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
> index 3e0b8f3..8109d18 100644
> --- a/drivers/rpmsg/rpmsg_char.c
> +++ b/drivers/rpmsg/rpmsg_char.c
> @@ -23,6 +23,7 @@
> #include <linux/rpmsg.h>
> #include <linux/skbuff.h>
> #include <linux/slab.h>
> +#include <linux/termios.h>
> #include <linux/uaccess.h>
> #include <uapi/linux/rpmsg.h>
>
> @@ -68,6 +69,8 @@ struct rpmsg_eptdev {
> struct sk_buff_head queue;
> wait_queue_head_t readq;
>
> + u32 remote_signals;
> + bool signals_pending;
Could you detail the need/use of signals_pending, in your implementation?
This is not obvious (at least for me)...
> };
>
> int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data)
> @@ -109,7 +112,22 @@ static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len,
> skb_queue_tail(&eptdev->queue, skb);
> spin_unlock(&eptdev->queue_lock);
>
> - /* wake up any blocking processes, waiting for new data */
> + wake_up_interruptible(&eptdev->readq);
> +
> + return 0;
> +}
> +
> +static int rpmsg_ept_flow_cb(struct rpmsg_device *rpdev, void *priv, bool enable)
> +{
> + struct rpmsg_eptdev *eptdev = priv;
> +
> + if (enable)
> + eptdev->remote_signals = TIOCM_DSR | TIOCM_CTS;
> + else
> + eptdev->remote_signals = 0;
> +
> + eptdev->signals_pending = true;
> +
> wake_up_interruptible(&eptdev->readq);
>
> return 0;
> @@ -146,6 +164,7 @@ static int rpmsg_eptdev_open(struct inode *inode, struct file *filp)
> return -EINVAL;
> }
>
> + ept->flow_cb = rpmsg_ept_flow_cb;
> eptdev->ept = ept;
> filp->private_data = eptdev;
> mutex_unlock(&eptdev->ept_lock);
> @@ -166,6 +185,7 @@ static int rpmsg_eptdev_release(struct inode *inode, struct file *filp)
> eptdev->ept = NULL;
> }
> mutex_unlock(&eptdev->ept_lock);
> + eptdev->signals_pending = false;
>
> /* Discard all SKBs */
> skb_queue_purge(&eptdev->queue);
> @@ -279,6 +299,9 @@ static __poll_t rpmsg_eptdev_poll(struct file *filp, poll_table *wait)
> if (!skb_queue_empty(&eptdev->queue))
> mask |= EPOLLIN | EPOLLRDNORM;
>
> + if (eptdev->signals_pending)
> + mask |= EPOLLPRI;
> +
> mask |= rpmsg_poll(eptdev->ept, filp, wait);
>
> return mask;
> @@ -289,14 +312,35 @@ static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
> {
> struct rpmsg_eptdev *eptdev = fp->private_data;
>
> - if (cmd != RPMSG_DESTROY_EPT_IOCTL)
> - return -EINVAL;
> -
> - /* Don't allow to destroy a default endpoint. */
> - if (eptdev->default_ept)
> - return -EINVAL;
> + bool set;
> + u32 val;
> + int ret;
> +
> + switch (cmd) {
> + case TIOCMGET:
> + eptdev->signals_pending = false;
> + ret = put_user(eptdev->remote_signals, (int __user *)arg);
> + break;
> + case TIOCMSET:
> + ret = get_user(val, (int __user *)arg);
> + if (ret)
> + break;
> + set = (val & (TIOCM_DTR | TIOCM_RTS)) ? true : false;
> + ret = rpmsg_set_flow_control(eptdev->ept, set, 0);
> + break;
I still wonder if it makes sense to implement serial IOCTRL in rpmsg_char.
I think it is quite dangerous to have such kind of mixed interface.
User application would want to use the serial interface should use the tty
interface.
For the rpmsg char, I would be in favor of creating a specific RPMSG IOCTRLs
to avoid confusion.
For instance:
- RPMSG_GET_SIGN_IOCTRL
- RPMSG_SET_SIGN_IOCTRL
With associated parameter corresponding to the bitmap proposed in my comment of
your patch 1/4.
Of course, this is only a suggestion, I let Bjorn and Mathieu comment.
Regards,
Arnaud
> + case RPMSG_DESTROY_EPT_IOCTL:
> + /* Don't allow to destroy a default endpoint. */
> + if (eptdev->default_ept) {
> + ret = -EINVAL;
> + break;
> + }
> + ret = rpmsg_chrdev_eptdev_destroy(&eptdev->dev, NULL);
> + break;
> + default:
> + ret = -EINVAL;
> + }
>
> - return rpmsg_chrdev_eptdev_destroy(&eptdev->dev, NULL);
> + return ret;
> }
>
> static const struct file_operations rpmsg_eptdev_fops = {
