[PATCH V4 4/4] rpmsg: char: Add signal callback and POLLPRI support

Arun Kumar Neelakantam
2020-05-13T05:11:41Z

Register a callback to get the signal notifications from rpmsg and
send POLLPRI mask to indicate the signal change in POLL system call.

Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
---
drivers/rpmsg/rpmsg_char.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)

diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
index e2f92f3..ae15d4f 100644
--- a/drivers/rpmsg/rpmsg_char.c
+++ b/drivers/rpmsg/rpmsg_char.c
@@ -64,6 +64,7 @@ struct rpmsg_ctrldev {
* @queue_lock: synchronization of @queue operations
* @queue: incoming message queue
* @readq: wait object for incoming queue
+ * @sig_pending:state of signal notification
*/
struct rpmsg_eptdev {
struct device dev;
@@ -78,6 +79,8 @@ struct rpmsg_eptdev {
spinlock_t queue_lock;
struct sk_buff_head queue;
wait_queue_head_t readq;
+
+ bool sig_pending;
};

static int rpmsg_eptdev_destroy(struct device *dev, void *data)
@@ -122,6 +125,19 @@ 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 old, u32 new)
+{
+ struct rpmsg_eptdev *eptdev = priv;
+
+ eptdev->sig_pending = true;
+
+ /* wake up any blocking processes, waiting for signal notification */
+ 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);
@@ -138,6 +154,7 @@ static int rpmsg_eptdev_open(struct inode *inode, struct file *filp)
return -EINVAL;
}

+ ept->sig_cb = rpmsg_sigs_cb;
eptdev->ept = ept;
filp->private_data = eptdev;

@@ -156,6 +173,7 @@ static int rpmsg_eptdev_release(struct inode *inode, struct file *filp)
eptdev->ept = NULL;
}
mutex_unlock(&eptdev->ept_lock);
+ eptdev->sig_pending = false;

/* Discard all SKBs */
skb_queue_purge(&eptdev->queue);
@@ -266,6 +284,9 @@ static __poll_t rpmsg_eptdev_poll(struct file *filp, poll_table *wait)
if (!skb_queue_empty(&eptdev->queue))
mask |= EPOLLIN | EPOLLRDNORM;

+ if (eptdev->sig_pending)
+ mask |= POLLPRI;
+
mask |= rpmsg_poll(eptdev->ept, filp, wait);

return mask;
@@ -309,6 +330,7 @@ static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,

switch (cmd) {
case TIOCMGET:
+ eptdev->sig_pending = false;
ret = rpmsg_get_signals(eptdev->ept);
if (ret >= 0)
ret = put_user(ret, (int __user *)arg);
--
2.7.4