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

[Arun Kumar Neelakantam]

Add TICOMGET and TIOCMSET ioctl support for rpmsg char device nodes
to get/set the low level transport signals.

Signed-off-by: Arun Kumar Neelakantam <aneela@xxxxxxxxxxxxxx>
---
 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@xxxxxxxxx>
  * 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