Re: [PATCH V4 3/4] rpmsg: char: Add TIOCMGET/TIOCMSET ioctl support

[Mathieu Poirier <mathieu.poirier@linaro.org>]

On Wed, May 13, 2020 at 10:41:10AM +0530, Arun Kumar Neelakantam wrote:
> Add TICOMGET and TIOCMSET ioctl support for rpmsg char device nodes

s/TICOMGET/TIOCMGET

> to get/set the low level transport signals.
> 
> Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
> ---
>  drivers/rpmsg/rpmsg_char.c | 53 +++++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 50 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
> index 4bbbacd..e2f92f3 100644
> --- a/drivers/rpmsg/rpmsg_char.c
> +++ b/drivers/rpmsg/rpmsg_char.c
> @@ -1,5 +1,6 @@
>  // SPDX-License-Identifier: GPL-2.0
>  /*
> + * Copyright (c) 2018, The Linux Foundation.
>   * Copyright (c) 2016, Linaro Ltd.
>   * Copyright (c) 2012, Michal Simek <monstr@monstr.eu>
>   * Copyright (c) 2012, PetaLogix
> @@ -19,6 +20,7 @@
>  #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>
>  
> @@ -269,15 +271,60 @@ static __poll_t rpmsg_eptdev_poll(struct file *filp, poll_table *wait)
>  	return mask;
>  }
>  
> +static int rpmsg_eptdev_tiocmset(struct file *fp, unsigned int cmd,
> +				 int __user *arg)
> +{
> +	struct rpmsg_eptdev *eptdev = fp->private_data;
> +	u32 set, clear, val;
> +	int ret;
> +
> +	ret = get_user(val, arg);
> +	if (ret)
> +		return ret;
> +	set = clear = 0;
> +	switch (cmd) {
> +	case TIOCMBIS:
> +		set = val;
> +		break;
> +	case TIOCMBIC:
> +		clear = val;
> +		break;
> +	case TIOCMSET:
> +		set = val;
> +		clear = ~val;
> +		break;
> +	}
> +
> +	set &= TIOCM_DTR | TIOCM_RTS | TIOCM_CD | TIOCM_RI;
> +	clear &= TIOCM_DTR | TIOCM_RTS | TIOCM_CD | TIOCM_RI;
> +
> +	return rpmsg_set_signals(eptdev->ept, set, clear);
> +}
> +
>  static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
>  			       unsigned long arg)
>  {
>  	struct rpmsg_eptdev *eptdev = fp->private_data;
> +	int ret;
>  
> -	if (cmd != RPMSG_DESTROY_EPT_IOCTL)
> -		return -EINVAL;
> +	switch (cmd) {
> +	case TIOCMGET:
> +		ret = rpmsg_get_signals(eptdev->ept);
> +		if (ret >= 0)
> +			ret = put_user(ret, (int __user *)arg);
> +		break;
> +	case TIOCMSET:
> +	case TIOCMBIS:
> +	case TIOCMBIC:
> +		ret = rpmsg_eptdev_tiocmset(fp, cmd, (int __user *)arg);
> +		break;
> +	case RPMSG_DESTROY_EPT_IOCTL:
> +		ret = rpmsg_eptdev_destroy(&eptdev->dev, NULL);
> +	default:
> +		ret = -EINVAL;
> +	}
>  
> -	return rpmsg_eptdev_destroy(&eptdev->dev, NULL);
> +	return ret;
>  }
>  
>  static const struct file_operations rpmsg_eptdev_fops = {
> -- 
> 2.7.4