Re: [PATCH V1 3/3] rpmsg: char: Add TIOCMGET/TIOCMSET ioctl support

Stephen Boyd
2021-09-30T16:36:41Z

Quoting Deepak Kumar Singh (2021-09-30 08:32:04)
> Add TICOMGET and TIOCMSET ioctl support for rpmsg char device nodes
> to get/set the low level transport signals.
>
> Signed-off-by: Chris Lew <clew@codeaurora.org>

Is Chris the author? Because if so then there should be a From: Chris
line before the commit text starts.

> Signed-off-by: Deepak Kumar Singh <deesin@codeaurora.org>
> ---
> drivers/rpmsg/rpmsg_char.c | 43 +++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 43 insertions(+)
>
> diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
> index 2bebc9b..60a889b 100644
> --- a/drivers/rpmsg/rpmsg_char.c
> +++ b/drivers/rpmsg/rpmsg_char.c
> @@ -19,6 +19,7 @@
> #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>
>
> @@ -76,6 +77,9 @@ struct rpmsg_eptdev {
> spinlock_t queue_lock;
> struct sk_buff_head queue;
> wait_queue_head_t readq;
> +
> + u32 rsigs;
> + bool sig_pending;
> };
>
> static int rpmsg_eptdev_destroy(struct device *dev, void *data)
> @@ -120,6 +124,18 @@ static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len,
> return 0;
> }
>
> +static int rpmsg_sigs_cb(struct rpmsg_device *rpdev, void *priv, u32 sigs)
> +{
> + struct rpmsg_eptdev *eptdev = priv;
> +
> + eptdev->rsigs = sigs;
> + eptdev->sig_pending = true;
> +
> + /* wake up any blocking processes, waiting for signal notification */

Comment would be better if it indicated what function these waiters are
in instead of saying what wake_up_interruptible() does. Also, what is
interruptible for?

> + wake_up_interruptible(&eptdev->readq);

Nitpick: Add newline here.

> + return 0;
> +}
> +
> static int rpmsg_eptdev_open(struct inode *inode, struct file *filp)
> {
> struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev);
> @@ -276,10 +297,32 @@ static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
> unsigned long arg)
> {
> struct rpmsg_eptdev *eptdev = fp->private_data;
> + bool set;
> + u32 val;
> + int ret;
>
> if (cmd != RPMSG_DESTROY_EPT_IOCTL)
> return -EINVAL;

This should be deleted?

>
> + switch (cmd) {
> + case TIOCMGET:
> + eptdev->sig_pending = false;
> + ret = put_user(eptdev->rsigs, (int __user *)arg);
> + break;
> + case TIOCMSET:
> + ret = get_user(val, (int __user *)arg);
> + if (ret)
> + break;
> + set = (val & TIOCM_DTR) ? true : false;
> + ret = rpmsg_set_flow_control(eptdev->ept, set);
> + break;
> + case RPMSG_DESTROY_EPT_IOCTL:
> + ret = rpmsg_eptdev_destroy(&eptdev->dev, NULL);
> + break;
> + default:
> + ret = -EINVAL;
> + }
> +
> return rpmsg_eptdev_destroy(&eptdev->dev, NULL);

This should be replaced with return ret?