On 4/22/23 12:42, Sarannya S wrote:
> From: Chris Lew <quic_clew@xxxxxxxxxxx>
>
> Add RPMSG_GET_OUTGOING_FLOWCONTROL and RPMSG_SET_INCOMING_FLOWCONTROL
> 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 | 49 ++++++++++++++++++++++++++++++++++++++++------
> include/uapi/linux/rpmsg.h | 11 ++++++++++-
> 2 files changed, 53 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
> index a271fce..d50908f 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>
Seems useless now
> #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;
>
> + bool remote_flow;
> + bool remote_flow_updated;
> };
>
> int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data)
> @@ -116,6 +119,18 @@ static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len,
> return 0;
> }
>
> +static int rpmsg_ept_flow_cb(struct rpmsg_device *rpdev, void *priv, bool enable)
> +{
> + struct rpmsg_eptdev *eptdev = priv;
> +
> + eptdev->remote_flow = enable;
> + eptdev->remote_flow_updated = true;
> +
> + wake_up_interruptible(&eptdev->readq);
> +
> + return 0;
> +}
> +
> static int rpmsg_eptdev_open(struct inode *inode, struct file *filp)
> {
> struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev);
> @@ -152,6 +167,7 @@ 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);
> @@ -172,6 +188,7 @@ static int rpmsg_eptdev_release(struct inode *inode, struct file *filp)
> eptdev->ept = NULL;
> }
> mutex_unlock(&eptdev->ept_lock);
> + eptdev->remote_flow_updated = false;
>
> /* Discard all SKBs */
> skb_queue_purge(&eptdev->queue);
> @@ -285,6 +302,9 @@ static __poll_t rpmsg_eptdev_poll(struct file *filp, poll_table *wait)
> if (!skb_queue_empty(&eptdev->queue))
> mask |= EPOLLIN | EPOLLRDNORM;
>
> + if (eptdev->remote_flow_updated)
> + mask |= EPOLLPRI;
> +
> mutex_lock(&eptdev->ept_lock);
> mask |= rpmsg_poll(eptdev->ept, filp, wait);
> mutex_unlock(&eptdev->ept_lock);
> @@ -297,14 +317,31 @@ 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;
> + bool set;
> + int ret;
>
> - /* Don't allow to destroy a default endpoint. */
> - if (eptdev->default_ept)
> - return -EINVAL;
> + switch (cmd) {
> + case RPMSG_GET_OUTGOING_FLOWCONTROL:
> + eptdev->remote_flow_updated = false;
> + ret = put_user(eptdev->remote_flow, (int __user *)arg);
If the rpmsg_set_flow_control is not implemented on remote side or in the
backend then we should return true by default.
Else the communication should not be possible if eptdev->remote_flow is not
initialized.
Perhaps adding a "flow_ctrl" boolean in the rpmsg_device (similar to the
"announce") would give the information if the flow control is supported or not.
This "flow_ctrl" boolean would be initialized by the backend.
Regards
Arnaud
> + break;
> + case RPMSG_SET_INCOMING_FLOWCONTROL:
> + set = !!arg;
> + ret = rpmsg_set_flow_control(eptdev->ept, set, eptdev->chinfo.dst);
> + break;
> + 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 = {
> diff --git a/include/uapi/linux/rpmsg.h b/include/uapi/linux/rpmsg.h
> index 1637e68..c955e27 100644
> --- a/include/uapi/linux/rpmsg.h
> +++ b/include/uapi/linux/rpmsg.h
> @@ -10,7 +10,6 @@
> #include <linux/types.h>
>
> #define RPMSG_ADDR_ANY 0xFFFFFFFF
> -
> /**
> * struct rpmsg_endpoint_info - endpoint info representation
> * @name: name of service
> @@ -43,4 +42,14 @@ struct rpmsg_endpoint_info {
> */
> #define RPMSG_RELEASE_DEV_IOCTL _IOW(0xb5, 0x4, struct rpmsg_endpoint_info)
>
> +/**
> + * Set the flow control for the remote rpmsg char device.
> + */
> +#define RPMSG_GET_OUTGOING_FLOWCONTROL _IOW(0xb5, 0x5, struct rpmsg_endpoint_info)
> +
> +/**
> + * Set the flow control for the local rpmsg char device.
> + */
> +#define RPMSG_SET_INCOMING_FLOWCONTROL _IOW(0xb5, 0x6, struct rpmsg_endpoint_info)
> +
> #endif
