[PATCH V9 0/3] rpmsg signaling/flowcontrol patches

[PATCH V9 0/3] rpmsg signaling/flowcontrol patches

[Sarannya S]

From: Sarannya S <sarannya@qti.qualcomm.com>

Changes from V8:
* Updated the argument for RPMSG_SET_INCOMING_FLOWCONTROL to int.
* Return -EINVAL if arg > 1 in RPMSG_SET_INCOMING_FLOWCONTROL.

Key changes from earlier revisions:
* Added two new RPMSG IOCTLs for rpmsg_char- RPMSG_GET_SIGNAL_IOCTRL and RPMSG_SET_SIGNAL_IOCTRL, to set/get the flow.
* Updated the cmd name 'RPM_CMD_SIGNALS' to 'GLINK_CMD_SIGNALS'.
* Return EOPNOTSUPP error in rpmsg_set_flow_control(), if the backend does not support flow control ops.
* For rpmsg_set_flow_control, change "EXPORT_SYMBOL" to "EXPORT_SYMBOL_GPL".
* Change return type of qcom_glink_handle_signals() from int to void.
* Added destination address of the endpoint as parameter in rpmsg_set_flow_control.
* Changed 'remote_flow' to bool type, and updated it's evaluation.
* Updated evaluation of 'set' in rpmsg_char as 'set = !!arg'.

Chris Lew (2):
  rpmsg: glink: Add support to handle signals command
  rpmsg: char: Add RPMSG GET/SET FLOWCONTROL IOCTL support

Deepak Kumar Singh (1):
  rpmsg: core: Add signal API support

 drivers/rpmsg/qcom_glink_native.c | 56 +++++++++++++++++++++++++++++++++++++++
 drivers/rpmsg/rpmsg_char.c        | 54 ++++++++++++++++++++++++++++++++-----
 drivers/rpmsg/rpmsg_core.c        | 21 +++++++++++++++
 drivers/rpmsg/rpmsg_internal.h    |  2 ++
 include/linux/rpmsg.h             | 15 +++++++++++
 include/uapi/linux/rpmsg.h        | 10 +++++++
 6 files changed, 152 insertions(+), 6 deletions(-)

-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

[PATCH V9 1/3] rpmsg: core: Add signal API support

[Sarannya S]

From: Deepak Kumar Singh <quic_deesin@quicinc.com>

Some transports like Glink support the state notifications between
clients using flow control signals similar to serial protocol signals.
Local glink client drivers can send and receive flow control status
to glink clients running on remote processors.

Add APIs to support sending and receiving of flow control status by
rpmsg clients.

Signed-off-by: Deepak Kumar Singh <quic_deesin@quicinc.com>
Signed-off-by: Sarannya S <quic_sarannya@quicinc.com>
---
 drivers/rpmsg/rpmsg_core.c     | 21 +++++++++++++++++++++
 drivers/rpmsg/rpmsg_internal.h |  2 ++
 include/linux/rpmsg.h          | 15 +++++++++++++++
 3 files changed, 38 insertions(+)

diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c
index 5039df7..32b550c 100644
--- a/drivers/rpmsg/rpmsg_core.c
+++ b/drivers/rpmsg/rpmsg_core.c
@@ -331,6 +331,25 @@ int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
 EXPORT_SYMBOL(rpmsg_trysend_offchannel);
 
 /**
+ * rpmsg_set_flow_control() - request remote to pause/resume transmission
+ * @ept:	the rpmsg endpoint
+ * @pause:	pause transmission
+ * @dst:	destination address of the endpoint
+ *
+ * Return: 0 on success and an appropriate error value on failure.
+ */
+int rpmsg_set_flow_control(struct rpmsg_endpoint *ept, bool pause, u32 dst)
+{
+	if (WARN_ON(!ept))
+		return -EINVAL;
+	if (!ept->ops->set_flow_control)
+		return -EOPNOTSUPP;
+
+	return ept->ops->set_flow_control(ept, pause, dst);
+}
+EXPORT_SYMBOL_GPL(rpmsg_set_flow_control);
+
+/**
  * rpmsg_get_mtu() - get maximum transmission buffer size for sending message.
  * @ept: the rpmsg endpoint
  *
@@ -539,6 +558,8 @@ static int rpmsg_dev_probe(struct device *dev)
 
 		rpdev->ept = ept;
 		rpdev->src = ept->addr;
+
+		ept->flow_cb = rpdrv->flowcontrol;
 	}
 
 	err = rpdrv->probe(rpdev);
diff --git a/drivers/rpmsg/rpmsg_internal.h b/drivers/rpmsg/rpmsg_internal.h
index 39b646d..b950d6f 100644
--- a/drivers/rpmsg/rpmsg_internal.h
+++ b/drivers/rpmsg/rpmsg_internal.h
@@ -55,6 +55,7 @@ struct rpmsg_device_ops {
  * @trysendto:		see @rpmsg_trysendto(), optional
  * @trysend_offchannel:	see @rpmsg_trysend_offchannel(), optional
  * @poll:		see @rpmsg_poll(), optional
+ * @set_flow_control:	see @rpmsg_set_flow_control(), optional
  * @get_mtu:		see @rpmsg_get_mtu(), optional
  *
  * Indirection table for the operations that a rpmsg backend should implement.
@@ -75,6 +76,7 @@ struct rpmsg_endpoint_ops {
 			     void *data, int len);
 	__poll_t (*poll)(struct rpmsg_endpoint *ept, struct file *filp,
 			     poll_table *wait);
+	int (*set_flow_control)(struct rpmsg_endpoint *ept, bool pause, u32 dst);
 	ssize_t (*get_mtu)(struct rpmsg_endpoint *ept);
 };
 
diff --git a/include/linux/rpmsg.h b/include/linux/rpmsg.h
index 523c98b..90d8e44 100644
--- a/include/linux/rpmsg.h
+++ b/include/linux/rpmsg.h
@@ -64,12 +64,14 @@ struct rpmsg_device {
 };
 
 typedef int (*rpmsg_rx_cb_t)(struct rpmsg_device *, void *, int, void *, u32);
+typedef int (*rpmsg_flowcontrol_cb_t)(struct rpmsg_device *, void *, bool);
 
 /**
  * struct rpmsg_endpoint - binds a local rpmsg address to its user
  * @rpdev: rpmsg channel device
  * @refcount: when this drops to zero, the ept is deallocated
  * @cb: rx callback handler
+ * @flow_cb: remote flow control callback handler
  * @cb_lock: must be taken before accessing/changing @cb
  * @addr: local rpmsg address
  * @priv: private data for the driver's use
@@ -92,6 +94,7 @@ struct rpmsg_endpoint {
 	struct rpmsg_device *rpdev;
 	struct kref refcount;
 	rpmsg_rx_cb_t cb;
+	rpmsg_flowcontrol_cb_t flow_cb;
 	struct mutex cb_lock;
 	u32 addr;
 	void *priv;
@@ -106,6 +109,7 @@ struct rpmsg_endpoint {
  * @probe: invoked when a matching rpmsg channel (i.e. device) is found
  * @remove: invoked when the rpmsg channel is removed
  * @callback: invoked when an inbound message is received on the channel
+ * @flowcontrol: invoked when remote side flow control request is received
  */
 struct rpmsg_driver {
 	struct device_driver drv;
@@ -113,6 +117,7 @@ struct rpmsg_driver {
 	int (*probe)(struct rpmsg_device *dev);
 	void (*remove)(struct rpmsg_device *dev);
 	int (*callback)(struct rpmsg_device *, void *, int, void *, u32);
+	int (*flowcontrol)(struct rpmsg_device *, void *, bool);
 };
 
 static inline u16 rpmsg16_to_cpu(struct rpmsg_device *rpdev, __rpmsg16 val)
@@ -192,6 +197,8 @@ __poll_t rpmsg_poll(struct rpmsg_endpoint *ept, struct file *filp,
 
 ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept);
 
+int rpmsg_set_flow_control(struct rpmsg_endpoint *ept, bool pause, u32 dst);
+
 #else
 
 static inline int rpmsg_register_device_override(struct rpmsg_device *rpdev,
@@ -316,6 +323,14 @@ static inline ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept)
 	return -ENXIO;
 }
 
+static inline int rpmsg_set_flow_control(struct rpmsg_endpoint *ept, bool pause, u32 dst)
+{
+	/* This shouldn't be possible */
+	WARN_ON(1);
+
+	return -ENXIO;
+}
+
 #endif /* IS_ENABLED(CONFIG_RPMSG) */
 
 /* use a macro to avoid include chaining to get THIS_MODULE */
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

[PATCH V9 2/3] rpmsg: glink: Add support to handle signals command

[Sarannya S]

From: Chris Lew <quic_clew@quicinc.com>

Remote peripherals send signal notifications over glink with commandID 15.

Add support to send and receive the signal command and based signals
enable or disable flow control with remote host.

Signed-off-by: Chris Lew <quic_clew@quicinc.com>
Signed-off-by: Deepak Kumar Singh <quic_deesin@quicinc.com>
Signed-off-by: Sarannya S <quic_sarannya@quicinc.com>
---
 drivers/rpmsg/qcom_glink_native.c | 56 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)

diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
index 1beb40a..bc87e6d 100644
--- a/drivers/rpmsg/qcom_glink_native.c
+++ b/drivers/rpmsg/qcom_glink_native.c
@@ -200,9 +200,15 @@ static const struct rpmsg_endpoint_ops glink_endpoint_ops;
 #define GLINK_CMD_TX_DATA_CONT		12
 #define GLINK_CMD_READ_NOTIF		13
 #define GLINK_CMD_RX_DONE_W_REUSE	14
+#define GLINK_CMD_SIGNALS		15
 
 #define GLINK_FEATURE_INTENTLESS	BIT(1)
 
+#define NATIVE_DTR_SIG			NATIVE_DSR_SIG
+#define NATIVE_DSR_SIG			BIT(31)
+#define NATIVE_RTS_SIG			NATIVE_CTS_SIG
+#define NATIVE_CTS_SIG			BIT(30)
+
 static void qcom_glink_rx_done_work(struct work_struct *work);
 
 static struct glink_channel *qcom_glink_alloc_channel(struct qcom_glink *glink,
@@ -1025,6 +1031,51 @@ static int qcom_glink_rx_open_ack(struct qcom_glink *glink, unsigned int lcid)
 	return 0;
 }
 
+/**
+ * qcom_glink_set_flow_control() - convert a signal cmd to wire format and
+ * 				   transmit
+ * @ept:	Rpmsg endpoint for channel.
+ * @pause:	Pause transmission
+ * @dst:	destination address of the endpoint
+ *
+ * Return: 0 on success or standard Linux error code.
+ */
+static int qcom_glink_set_flow_control(struct rpmsg_endpoint *ept, bool pause, u32 dst)
+{
+	struct glink_channel *channel = to_glink_channel(ept);
+	struct qcom_glink *glink = channel->glink;
+	struct glink_msg msg;
+	u32 sigs = 0;
+
+	if (pause)
+		sigs |= NATIVE_DTR_SIG | NATIVE_RTS_SIG;
+
+	msg.cmd = cpu_to_le16(GLINK_CMD_SIGNALS);
+	msg.param1 = cpu_to_le16(channel->lcid);
+	msg.param2 = cpu_to_le32(sigs);
+
+	return qcom_glink_tx(glink, &msg, sizeof(msg), NULL, 0, true);
+}
+
+static void qcom_glink_handle_signals(struct qcom_glink *glink,
+				     unsigned int rcid, unsigned int sigs)
+{
+	struct glink_channel *channel;
+	unsigned long flags;
+	bool enable;
+
+	spin_lock_irqsave(&glink->idr_lock, flags);
+	channel = idr_find(&glink->rcids, rcid);
+	spin_unlock_irqrestore(&glink->idr_lock, flags);
+	if (!channel)
+		dev_err(glink->dev, "signal for non-existing channel\n");
+
+	enable = sigs & NATIVE_DSR_SIG || sigs & NATIVE_CTS_SIG;
+
+	if (channel->ept.flow_cb)
+		channel->ept.flow_cb(channel->ept.rpdev, channel->ept.priv, enable);
+}
+
 void qcom_glink_native_rx(struct qcom_glink *glink)
 {
 	struct glink_msg msg;
@@ -1086,6 +1137,10 @@ void qcom_glink_native_rx(struct qcom_glink *glink)
 			qcom_glink_handle_intent_req_ack(glink, param1, param2);
 			qcom_glink_rx_advance(glink, ALIGN(sizeof(msg), 8));
 			break;
+		case GLINK_CMD_SIGNALS:
+			qcom_glink_handle_signals(glink, param1, param2);
+			qcom_glink_rx_advance(glink, ALIGN(sizeof(msg), 8));
+			break;
 		default:
 			dev_err(glink->dev, "unhandled rx cmd: %d\n", cmd);
 			ret = -EINVAL;
@@ -1446,6 +1501,7 @@ static const struct rpmsg_endpoint_ops glink_endpoint_ops = {
 	.sendto = qcom_glink_sendto,
 	.trysend = qcom_glink_trysend,
 	.trysendto = qcom_glink_trysendto,
+	.set_flow_control = qcom_glink_set_flow_control,
 };
 
 static void qcom_glink_rpdev_release(struct device *dev)
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

[PATCH V9 3/3] rpmsg: char: Add RPMSG GET/SET FLOWCONTROL IOCTL support

[Sarannya S]

From: Chris Lew <quic_clew@quicinc.com>

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@quicinc.com>
Signed-off-by: Deepak Kumar Singh <quic_deesin@quicinc.com>
Signed-off-by: Sarannya S <quic_sarannya@quicinc.com>
---
 drivers/rpmsg/rpmsg_char.c | 54 ++++++++++++++++++++++++++++++++++++++++------
 include/uapi/linux/rpmsg.h | 10 +++++++++
 2 files changed, 58 insertions(+), 6 deletions(-)

diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
index a271fce..09833ad 100644
--- a/drivers/rpmsg/rpmsg_char.c
+++ b/drivers/rpmsg/rpmsg_char.c
@@ -52,6 +52,8 @@ static DEFINE_IDA(rpmsg_minor_ida);
  * @readq:	wait object for incoming queue
  * @default_ept: set to channel default endpoint if the default endpoint should be re-used
  *              on device open to prevent endpoint address update.
+ * remote_flow_restricted: to indicate if the remote has requested for flow to be limited
+ * remote_flow_updated: to indicate if the flow control has been requested
  */
 struct rpmsg_eptdev {
 	struct device dev;
@@ -68,6 +70,8 @@ struct rpmsg_eptdev {
 	struct sk_buff_head queue;
 	wait_queue_head_t readq;
 
+	bool remote_flow_restricted;
+	bool remote_flow_updated;
 };
 
 int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data)
@@ -116,6 +120,18 @@ 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_restricted = 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 +168,7 @@ 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 +189,7 @@ 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 +303,9 @@ 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 +318,35 @@ 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_restricted, (int __user *)arg);
+		break;
+	case RPMSG_SET_INCOMING_FLOWCONTROL:
+		if (arg > 1) {
+			ret = -EINVAL;
+			break;
+		}
+		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..f0c8da2 100644
--- a/include/uapi/linux/rpmsg.h
+++ b/include/uapi/linux/rpmsg.h
@@ -43,4 +43,14 @@ struct rpmsg_endpoint_info {
  */
 #define RPMSG_RELEASE_DEV_IOCTL	_IOW(0xb5, 0x4, struct rpmsg_endpoint_info)
 
+/**
+ * Get the flow control state of the remote rpmsg char device.
+ */
+#define RPMSG_GET_OUTGOING_FLOWCONTROL _IOR(0xb5, 0x5, int)
+
+/**
+ * Set the flow control state of the local rpmsg char device.
+ */
+#define RPMSG_SET_INCOMING_FLOWCONTROL _IOR(0xb5, 0x6, int)
+
 #endif
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH V9 3/3] rpmsg: char: Add RPMSG GET/SET FLOWCONTROL IOCTL support

[Arnaud POULIQUEN]

On 7/6/23 23:41, Sarannya S wrote:
> From: Chris Lew <quic_clew@quicinc.com>
> 
> 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@quicinc.com>
> Signed-off-by: Deepak Kumar Singh <quic_deesin@quicinc.com>
> Signed-off-by: Sarannya S <quic_sarannya@quicinc.com>
> ---
>  drivers/rpmsg/rpmsg_char.c | 54 ++++++++++++++++++++++++++++++++++++++++------
>  include/uapi/linux/rpmsg.h | 10 +++++++++
>  2 files changed, 58 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
> index a271fce..09833ad 100644
> --- a/drivers/rpmsg/rpmsg_char.c
> +++ b/drivers/rpmsg/rpmsg_char.c
> @@ -52,6 +52,8 @@ static DEFINE_IDA(rpmsg_minor_ida);
>   * @readq:	wait object for incoming queue
>   * @default_ept: set to channel default endpoint if the default endpoint should be re-used
>   *              on device open to prevent endpoint address update.
> + * remote_flow_restricted: to indicate if the remote has requested for flow to be limited
> + * remote_flow_updated: to indicate if the flow control has been requested
>   */
>  struct rpmsg_eptdev {
>  	struct device dev;
> @@ -68,6 +70,8 @@ struct rpmsg_eptdev {
>  	struct sk_buff_head queue;
>  	wait_queue_head_t readq;
>  
> +	bool remote_flow_restricted;
> +	bool remote_flow_updated;
>  };
>  
>  int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data)
> @@ -116,6 +120,18 @@ 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_restricted = 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 +168,7 @@ 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 +189,7 @@ 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 +303,9 @@ 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 +318,35 @@ 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_restricted, (int __user *)arg);
> +		break;
> +	case RPMSG_SET_INCOMING_FLOWCONTROL:
> +		if (arg > 1) {
> +			ret = -EINVAL;
> +			break;
> +		}
> +		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..f0c8da2 100644
> --- a/include/uapi/linux/rpmsg.h
> +++ b/include/uapi/linux/rpmsg.h
> @@ -43,4 +43,14 @@ struct rpmsg_endpoint_info {
>   */
>  #define RPMSG_RELEASE_DEV_IOCTL	_IOW(0xb5, 0x4, struct rpmsg_endpoint_info)
>  
> +/**
> + * Get the flow control state of the remote rpmsg char device.
> + */
> +#define RPMSG_GET_OUTGOING_FLOWCONTROL _IOR(0xb5, 0x5, int)
> +
> +/**
> + * Set the flow control state of the local rpmsg char device.
> + */
> +#define RPMSG_SET_INCOMING_FLOWCONTROL _IOR(0xb5, 0x6, int)
> +

Seems that it is not the use to document the parameters for IOCTL
but I wonder if documenting the use of the RPMSG_GET_OUTGOING_FLOWCONTROL
and RPMSG_SET_INCOMING_FLOWCONTROL parameter could help users to implement
the IOCTL...

For the series
Acked-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>

Thanks,
Arnaud

>  #endif

Re: [PATCH V9 0/3] rpmsg signaling/flowcontrol patches

[Bjorn Andersson]

On Fri, 07 Jul 2023 03:11:35 +0530, Sarannya S wrote:
> From: Sarannya S <sarannya@qti.qualcomm.com>
> 
> Changes from V8:
> * Updated the argument for RPMSG_SET_INCOMING_FLOWCONTROL to int.
> * Return -EINVAL if arg > 1 in RPMSG_SET_INCOMING_FLOWCONTROL.
> 
> Key changes from earlier revisions:
> * Added two new RPMSG IOCTLs for rpmsg_char- RPMSG_GET_SIGNAL_IOCTRL and RPMSG_SET_SIGNAL_IOCTRL, to set/get the flow.
> * Updated the cmd name 'RPM_CMD_SIGNALS' to 'GLINK_CMD_SIGNALS'.
> * Return EOPNOTSUPP error in rpmsg_set_flow_control(), if the backend does not support flow control ops.
> * For rpmsg_set_flow_control, change "EXPORT_SYMBOL" to "EXPORT_SYMBOL_GPL".
> * Change return type of qcom_glink_handle_signals() from int to void.
> * Added destination address of the endpoint as parameter in rpmsg_set_flow_control.
> * Changed 'remote_flow' to bool type, and updated it's evaluation.
> * Updated evaluation of 'set' in rpmsg_char as 'set = !!arg'.
> 
> [...]

Applied, thanks!

[1/3] rpmsg: core: Add signal API support
      commit: 8ce49c2a2aa53afde9a20a8ce02b069d3b262af0
[2/3] rpmsg: glink: Add support to handle signals command
      commit: a2b73aa512a4a90dda7dd5bb38b26b4f1381adbb
[3/3] rpmsg: char: Add RPMSG GET/SET FLOWCONTROL IOCTL support
      commit: 5550201c0fe26a76c53983bd36a58d4c4395ec22

Best regards,
-- 
Bjorn Andersson <andersson@kernel.org>