[PATCH v2 08/17] rpmsg: Indirection table for rpmsg_endpoint operations

[Bjorn Andersson]

Add indirection table for rpmsg_endpoint related operations and move
virtio implementation behind this, this finishes of the decoupling of
the virtio implementation from the public API.

Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
---

Per Loic's comment I did consider adding parameter validation to the exposed
functions in this patch, but as the previous implementation did not gracefully
handle bad input parameters I decided to defer this until after this series has
been merged.

Changes since v1:
- Split indirection table into device and endpoint ops
- Moved ops pointer to the public structs to reduce code clutter
- Kerneldoc for rpmsg_endpoint_ops

 drivers/rpmsg/virtio_rpmsg_bus.c | 85 ++++++++++++++++++++++++++++++++++++++--
 include/linux/rpmsg.h            | 62 +++++++++++++++++------------
 2 files changed, 120 insertions(+), 27 deletions(-)

diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c
index 605e09c96d65..e5f256791fd3 100644
--- a/drivers/rpmsg/virtio_rpmsg_bus.c
+++ b/drivers/rpmsg/virtio_rpmsg_bus.c
@@ -107,6 +107,18 @@ struct virtproc_info {
 /* Address 53 is reserved for advertising remote services */
 #define RPMSG_NS_ADDR			(53)
 
+static void virtio_rpmsg_destroy_ept(struct rpmsg_endpoint *ept);
+static int virtio_rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len);
+static int virtio_rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len,
+			       u32 dst);
+static int virtio_rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src,
+					u32 dst, void *data, int len);
+static int virtio_rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len);
+static int virtio_rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data,
+				  int len, u32 dst);
+static int virtio_rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src,
+					   u32 dst, void *data, int len);
+
 /* sysfs show configuration fields */
 #define rpmsg_show_attr(field, path, format_string)			\
 static ssize_t								\
@@ -172,6 +184,16 @@ static int rpmsg_uevent(struct device *dev, struct kobj_uevent_env *env)
 					rpdev->id.name);
 }
 
+static const struct rpmsg_endpoint_ops virtio_endpoint_ops = {
+	.destroy_ept = virtio_rpmsg_destroy_ept,
+	.send = virtio_rpmsg_send,
+	.sendto = virtio_rpmsg_sendto,
+	.send_offchannel = virtio_rpmsg_send_offchannel,
+	.trysend = virtio_rpmsg_trysend,
+	.trysendto = virtio_rpmsg_trysendto,
+	.trysend_offchannel = virtio_rpmsg_trysend_offchannel,
+};
+
 /**
  * __ept_release() - deallocate an rpmsg endpoint
  * @kref: the ept's reference count
@@ -212,6 +234,7 @@ static struct rpmsg_endpoint *__rpmsg_create_ept(struct virtproc_info *vrp,
 	ept->rpdev = rpdev;
 	ept->cb = cb;
 	ept->priv = priv;
+	ept->ops = &virtio_endpoint_ops;
 
 	/* do we need to allocate a local address ? */
 	if (addr == RPMSG_ADDR_ANY) {
@@ -285,10 +308,15 @@ __rpmsg_destroy_ept(struct virtproc_info *vrp, struct rpmsg_endpoint *ept)
  */
 void rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
 {
-	__rpmsg_destroy_ept(ept->rpdev->vrp, ept);
+	ept->ops->destroy_ept(ept);
 }
 EXPORT_SYMBOL(rpmsg_destroy_ept);
 
+static void virtio_rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
+{
+	__rpmsg_destroy_ept(ept->rpdev->vrp, ept);
+}
+
 /*
  * when an rpmsg driver is probed with a channel, we seamlessly create
  * it an endpoint, binding its rx callback to a unique local rpmsg
@@ -657,8 +685,9 @@ static void rpmsg_downref_sleepers(struct virtproc_info *vrp)
  *
  * Returns 0 on success and an appropriate error value on failure.
  */
-int rpmsg_send_offchannel_raw(struct rpmsg_device *rpdev, u32 src, u32 dst,
-			      void *data, int len, bool wait)
+static int rpmsg_send_offchannel_raw(struct rpmsg_device *rpdev,
+				     u32 src, u32 dst,
+				     void *data, int len, bool wait)
 {
 	struct virtproc_info *vrp = rpdev->vrp;
 	struct device *dev = &rpdev->dev;
@@ -754,6 +783,56 @@ out:
 }
 EXPORT_SYMBOL(rpmsg_send_offchannel_raw);
 
+static int virtio_rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len)
+{
+	struct rpmsg_device *rpdev = ept->rpdev;
+	u32 src = ept->addr, dst = rpdev->dst;
+
+	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
+}
+
+static int virtio_rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len,
+			       u32 dst)
+{
+	struct rpmsg_device *rpdev = ept->rpdev;
+	u32 src = ept->addr;
+
+	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
+}
+
+static int virtio_rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src,
+					u32 dst, void *data, int len)
+{
+	struct rpmsg_device *rpdev = ept->rpdev;
+
+	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
+}
+
+static int virtio_rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len)
+{
+	struct rpmsg_device *rpdev = ept->rpdev;
+	u32 src = ept->addr, dst = rpdev->dst;
+
+	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
+}
+
+static int virtio_rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data,
+				  int len, u32 dst)
+{
+	struct rpmsg_device *rpdev = ept->rpdev;
+	u32 src = ept->addr;
+
+	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
+}
+
+static int virtio_rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src,
+					   u32 dst, void *data, int len)
+{
+	struct rpmsg_device *rpdev = ept->rpdev;
+
+	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
+}
+
 static int rpmsg_recv_single(struct virtproc_info *vrp, struct device *dev,
 			     struct rpmsg_hdr *msg, unsigned int len)
 {
diff --git a/include/linux/rpmsg.h b/include/linux/rpmsg.h
index 9fdcfc7c7837..d54458effd54 100644
--- a/include/linux/rpmsg.h
+++ b/include/linux/rpmsg.h
@@ -96,8 +96,10 @@ enum rpmsg_ns_flags {
 #define RPMSG_ADDR_ANY		0xFFFFFFFF
 
 struct virtproc_info;
+struct rpmsg_device;
 struct rpmsg_endpoint;
 struct rpmsg_device_ops;
+struct rpmsg_endpoint_ops;
 
 /**
  * struct rpmsg_channel_info - channel info representation
@@ -184,6 +186,36 @@ struct rpmsg_endpoint {
 	struct mutex cb_lock;
 	u32 addr;
 	void *priv;
+
+	const struct rpmsg_endpoint_ops *ops;
+};
+
+/**
+ * struct rpmsg_endpoint_ops - indirection table for rpmsg_endpoint operations
+ * @destroy_ept:	destroy the given endpoint, required
+ * @send:		see @rpmsg_send(), required
+ * @sendto:		see @rpmsg_sendto(), optional
+ * @send_offchannel:	see @rpmsg_send_offchannel(), optional
+ * @trysend:		see @rpmsg_trysend(), required
+ * @trysendto:		see @rpmsg_trysendto(), optional
+ * @trysend_offchannel:	see @rpmsg_trysend_offchannel(), optional
+ *
+ * Indirection table for the operations that a rpmsg backend should implement.
+ * In addition to @destroy_ept, the backend must at least implement @send and
+ * @trysend, while the variants sending data off-channel are optional.
+ */
+struct rpmsg_endpoint_ops {
+	void (*destroy_ept)(struct rpmsg_endpoint *ept);
+
+	int (*send)(struct rpmsg_endpoint *ept, void *data, int len);
+	int (*sendto)(struct rpmsg_endpoint *ept, void *data, int len, u32 dst);
+	int (*send_offchannel)(struct rpmsg_endpoint *ept, u32 src, u32 dst,
+				  void *data, int len);
+
+	int (*trysend)(struct rpmsg_endpoint *ept, void *data, int len);
+	int (*trysendto)(struct rpmsg_endpoint *ept, void *data, int len, u32 dst);
+	int (*trysend_offchannel)(struct rpmsg_endpoint *ept, u32 src, u32 dst,
+			     void *data, int len);
 };
 
 /**
@@ -210,8 +242,6 @@ void rpmsg_destroy_ept(struct rpmsg_endpoint *);
 struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_device *,
 					rpmsg_rx_cb_t cb, void *priv,
 					struct rpmsg_channel_info chinfo);
-int
-rpmsg_send_offchannel_raw(struct rpmsg_device *, u32, u32, void *, int, bool);
 
 /* use a macro to avoid include chaining to get THIS_MODULE */
 #define register_rpmsg_driver(drv) \
@@ -249,10 +279,7 @@ rpmsg_send_offchannel_raw(struct rpmsg_device *, u32, u32, void *, int, bool);
  */
 static inline int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len)
 {
-	struct rpmsg_device *rpdev = ept->rpdev;
-	u32 src = ept->addr, dst = rpdev->dst;
-
-	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
+	return ept->ops->send(ept, data, len);
 }
 
 /**
@@ -276,10 +303,7 @@ static inline int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len)
 static inline
 int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
 {
-	struct rpmsg_device *rpdev = ept->rpdev;
-	u32 src = ept->addr;
-
-	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
+	return ept->ops->sendto(ept, data, len, dst);
 }
 
 /**
@@ -306,9 +330,7 @@ static inline
 int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
 			  void *data, int len)
 {
-	struct rpmsg_device *rpdev = ept->rpdev;
-
-	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
+	return ept->ops->send_offchannel(ept, src, dst, data, len);
 }
 
 /**
@@ -331,10 +353,7 @@ int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
 static inline
 int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len)
 {
-	struct rpmsg_device *rpdev = ept->rpdev;
-	u32 src = ept->addr, dst = rpdev->dst;
-
-	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
+	return ept->ops->trysend(ept, data, len);
 }
 
 /**
@@ -357,10 +376,7 @@ int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len)
 static inline
 int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
 {
-	struct rpmsg_device *rpdev = ept->rpdev;
-	u32 src = ept->addr;
-
-	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
+	return ept->ops->trysendto(ept, data, len, dst);
 }
 
 /**
@@ -386,9 +402,7 @@ static inline
 int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
 			     void *data, int len)
 {
-	struct rpmsg_device *rpdev = ept->rpdev;
-
-	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
+	return ept->ops->trysend_offchannel(ept, src, dst, data, len);
 }
 
 #endif /* _LINUX_RPMSG_H */
-- 
2.5.0