Merge tag 'rpmsg-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/remoteproc/linux

Pull rpmsg updates from Bjorn Andersson:
 "Add support for the GLINK flow control signals, and expose this to the
  user through the rpmsg_char interface. Add missing kstrdup() failure
  handling during allocation of GLINK channel objects"

* tag 'rpmsg-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/remoteproc/linux:
  rpmsg: glink: Avoid dereferencing NULL channel
  rpmsg: glink: Add check for kstrdup
  rpmsg: char: Add RPMSG GET/SET FLOWCONTROL IOCTL support
  rpmsg: glink: Add support to handle signals command
  rpmsg: core: Add signal API support

2 files changed, 25 insertions, 0 deletions

diff --git a/include/linux/rpmsg.h b/include/linux/rpmsg.h
index 523c98b96cb4..90d8e4475f80 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 */
diff --git a/include/uapi/linux/rpmsg.h b/include/uapi/linux/rpmsg.h
index 1637e68177d9..f0c8da2b185b 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