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

Deepak Kumar Singh
2021-09-30T15:33:02Z

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>
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 */
+ 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);
@@ -139,6 +155,7 @@ 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;

@@ -157,6 +174,7 @@ 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);
@@ -267,6 +285,9 @@ 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 |= EPOLLPRI;
+
mask |= rpmsg_poll(eptdev->ept, filp, wait);

return mask;
@@ -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;

+ 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);
}

--
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