rpmsg updates for v4.10

Argument validation in public functions, function stubs for COMPILE_TEST-ing
 clients, preparation for exposing rpmsg endponts to user space and minor
 Qualcomm SMD fixes.
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Merge tag 'rpmsg-v4.10' of git://github.com/andersson/remoteproc

Pull rpmsg updates from Bjorn Andersson:
 "Argument validation in public functions, function stubs for
  COMPILE_TEST-ing clients, preparation for exposing rpmsg endponts
  to user space and minor Qualcomm SMD fixes"

* tag 'rpmsg-v4.10' of git://github.com/andersson/remoteproc:
  dt-binding: soc: qcom: smd: Add label property
  rpmsg: qcom_smd: Correct return value for O_NONBLOCK
  rpmsg: Provide function stubs for API
  rpmsg: Handle invalid parameters in public API
  rpmsg: Support drivers without primary endpoint
  rpmsg: Introduce a driver override mechanism
  rpmsg: smd: Reduce restrictions when finding channel

drivers/rpmsg/qcom_smd.c

@@ -740,7 +740,7 @@ static int __qcom_smd_send(struct qcom_smd_channel *channel, const void *data,
 
 	while (qcom_smd_get_tx_avail(channel) < tlen) {
 		if (!wait) {
-			ret = -ENOMEM;
+			ret = -EAGAIN;
 			goto out;
 		}
 
@@ -821,20 +821,13 @@ qcom_smd_find_channel(struct qcom_smd_edge *edge, const char *name)
 	struct qcom_smd_channel *channel;
 	struct qcom_smd_channel *ret = NULL;
 	unsigned long flags;
-	unsigned state;
 
 	spin_lock_irqsave(&edge->channels_lock, flags);
 	list_for_each_entry(channel, &edge->channels, list) {
-		if (strcmp(channel->name, name))
-			continue;
-
-		state = GET_RX_CHANNEL_INFO(channel, state);
-		if (state != SMD_CHANNEL_OPENING &&
-		    state != SMD_CHANNEL_OPENED)
-			continue;
-
-		ret = channel;
-		break;
+		if (!strcmp(channel->name, name)) {
+			ret = channel;
+			break;
+		}
 	}
 	spin_unlock_irqrestore(&edge->channels_lock, flags);
 

drivers/rpmsg/rpmsg_core.c

@@ -71,6 +71,9 @@ struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_device *rpdev,
 					rpmsg_rx_cb_t cb, void *priv,
 					struct rpmsg_channel_info chinfo)
 {
+	if (WARN_ON(!rpdev))
+		return ERR_PTR(-EINVAL);
+
 	return rpdev->ops->create_ept(rpdev, cb, priv, chinfo);
 }
 EXPORT_SYMBOL(rpmsg_create_ept);
@@ -80,11 +83,13 @@ EXPORT_SYMBOL(rpmsg_create_ept);
  * @ept: endpoing to destroy
  *
  * Should be used by drivers to destroy an rpmsg endpoint previously
- * created with rpmsg_create_ept().
+ * created with rpmsg_create_ept(). As with other types of "free" NULL
+ * is a valid parameter.
  */
 void rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
 {
-	ept->ops->destroy_ept(ept);
+	if (ept)
+		ept->ops->destroy_ept(ept);
 }
 EXPORT_SYMBOL(rpmsg_destroy_ept);
 
@@ -108,6 +113,11 @@ EXPORT_SYMBOL(rpmsg_destroy_ept);
  */
 int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len)
 {
+	if (WARN_ON(!ept))
+		return -EINVAL;
+	if (!ept->ops->send)
+		return -ENXIO;
+
 	return ept->ops->send(ept, data, len);
 }
 EXPORT_SYMBOL(rpmsg_send);
@@ -132,6 +142,11 @@ EXPORT_SYMBOL(rpmsg_send);
  */
 int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
 {
+	if (WARN_ON(!ept))
+		return -EINVAL;
+	if (!ept->ops->sendto)
+		return -ENXIO;
+
 	return ept->ops->sendto(ept, data, len, dst);
 }
 EXPORT_SYMBOL(rpmsg_sendto);
@@ -159,6 +174,11 @@ EXPORT_SYMBOL(rpmsg_sendto);
 int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
 			  void *data, int len)
 {
+	if (WARN_ON(!ept))
+		return -EINVAL;
+	if (!ept->ops->send_offchannel)
+		return -ENXIO;
+
 	return ept->ops->send_offchannel(ept, src, dst, data, len);
 }
 EXPORT_SYMBOL(rpmsg_send_offchannel);
@@ -182,6 +202,11 @@ EXPORT_SYMBOL(rpmsg_send_offchannel);
  */
 int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len)
 {
+	if (WARN_ON(!ept))
+		return -EINVAL;
+	if (!ept->ops->trysend)
+		return -ENXIO;
+
 	return ept->ops->trysend(ept, data, len);
 }
 EXPORT_SYMBOL(rpmsg_trysend);
@@ -205,6 +230,11 @@ EXPORT_SYMBOL(rpmsg_trysend);
  */
 int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
 {
+	if (WARN_ON(!ept))
+		return -EINVAL;
+	if (!ept->ops->trysendto)
+		return -ENXIO;
+
 	return ept->ops->trysendto(ept, data, len, dst);
 }
 EXPORT_SYMBOL(rpmsg_trysendto);
@@ -231,6 +261,11 @@ EXPORT_SYMBOL(rpmsg_trysendto);
 int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
 			     void *data, int len)
 {
+	if (WARN_ON(!ept))
+		return -EINVAL;
+	if (!ept->ops->trysend_offchannel)
+		return -ENXIO;
+
 	return ept->ops->trysend_offchannel(ept, src, dst, data, len);
 }
 EXPORT_SYMBOL(rpmsg_trysend_offchannel);
@@ -315,6 +350,9 @@ static int rpmsg_dev_match(struct device *dev, struct device_driver *drv)
 	const struct rpmsg_device_id *ids = rpdrv->id_table;
 	unsigned int i;
 
+	if (rpdev->driver_override)
+		return !strcmp(rpdev->driver_override, drv->name);
+
 	if (ids)
 		for (i = 0; ids[i].name[0]; i++)
 			if (rpmsg_id_match(rpdev, &ids[i]))
@@ -344,27 +382,30 @@ static int rpmsg_dev_probe(struct device *dev)
 	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
 	struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver);
 	struct rpmsg_channel_info chinfo = {};
-	struct rpmsg_endpoint *ept;
+	struct rpmsg_endpoint *ept = NULL;
 	int err;
 
-	strncpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE);
-	chinfo.src = rpdev->src;
-	chinfo.dst = RPMSG_ADDR_ANY;
+	if (rpdrv->callback) {
+		strncpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE);
+		chinfo.src = rpdev->src;
+		chinfo.dst = RPMSG_ADDR_ANY;
 
-	ept = rpmsg_create_ept(rpdev, rpdrv->callback, NULL, chinfo);
-	if (!ept) {
-		dev_err(dev, "failed to create endpoint\n");
-		err = -ENOMEM;
-		goto out;
+		ept = rpmsg_create_ept(rpdev, rpdrv->callback, NULL, chinfo);
+		if (!ept) {
+			dev_err(dev, "failed to create endpoint\n");
+			err = -ENOMEM;
+			goto out;
+		}
+
+		rpdev->ept = ept;
+		rpdev->src = ept->addr;
 	}
 
-	rpdev->ept = ept;
-	rpdev->src = ept->addr;
-
 	err = rpdrv->probe(rpdev);
 	if (err) {
 		dev_err(dev, "%s: failed: %d\n", __func__, err);
-		rpmsg_destroy_ept(ept);
+		if (ept)
+			rpmsg_destroy_ept(ept);
 		goto out;
 	}
 
@@ -385,7 +426,8 @@ static int rpmsg_dev_remove(struct device *dev)
 
 	rpdrv->remove(rpdev);
 
-	rpmsg_destroy_ept(rpdev->ept);
+	if (rpdev->ept)
+		rpmsg_destroy_ept(rpdev->ept);
 
 	return err;
 }

include/linux/rpmsg.h

@@ -37,6 +37,7 @@
 
 #include <linux/types.h>
 #include <linux/device.h>
+#include <linux/err.h>
 #include <linux/mod_devicetable.h>
 #include <linux/kref.h>
 #include <linux/mutex.h>
@@ -64,6 +65,7 @@ struct rpmsg_channel_info {
  * rpmsg_device - device that belong to the rpmsg bus
  * @dev: the device struct
  * @id: device id (used to match between rpmsg drivers and devices)
+ * @driver_override: driver name to force a match
  * @src: local address
  * @dst: destination address
  * @ept: the rpmsg endpoint of this channel
@@ -72,6 +74,7 @@ struct rpmsg_channel_info {
 struct rpmsg_device {
 	struct device dev;
 	struct rpmsg_device_id id;
+	char *driver_override;
 	u32 src;
 	u32 dst;
 	struct rpmsg_endpoint *ept;
@@ -132,6 +135,8 @@ struct rpmsg_driver {
 	int (*callback)(struct rpmsg_device *, void *, int, void *, u32);
 };
 
+#if IS_ENABLED(CONFIG_RPMSG)
+
 int register_rpmsg_device(struct rpmsg_device *dev);
 void unregister_rpmsg_device(struct rpmsg_device *dev);
 int __register_rpmsg_driver(struct rpmsg_driver *drv, struct module *owner);
@@ -141,6 +146,116 @@ struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_device *,
 					rpmsg_rx_cb_t cb, void *priv,
 					struct rpmsg_channel_info chinfo);
 
+int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len);
+int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst);
+int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
+			  void *data, int len);
+
+int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len);
+int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst);
+int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
+			     void *data, int len);
+
+#else
+
+static inline int register_rpmsg_device(struct rpmsg_device *dev)
+{
+	return -ENXIO;
+}
+
+static inline void unregister_rpmsg_device(struct rpmsg_device *dev)
+{
+	/* This shouldn't be possible */
+	WARN_ON(1);
+}
+
+static inline int __register_rpmsg_driver(struct rpmsg_driver *drv,
+					  struct module *owner)
+{
+	/* This shouldn't be possible */
+	WARN_ON(1);
+
+	return -ENXIO;
+}
+
+static inline void unregister_rpmsg_driver(struct rpmsg_driver *drv)
+{
+	/* This shouldn't be possible */
+	WARN_ON(1);
+}
+
+static inline void rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
+{
+	/* This shouldn't be possible */
+	WARN_ON(1);
+}
+
+static inline struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_device *rpdev,
+						      rpmsg_rx_cb_t cb,
+						      void *priv,
+						      struct rpmsg_channel_info chinfo)
+{
+	/* This shouldn't be possible */
+	WARN_ON(1);
+
+	return ERR_PTR(-ENXIO);
+}
+
+static inline int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len)
+{
+	/* This shouldn't be possible */
+	WARN_ON(1);
+
+	return -ENXIO;
+}
+
+static inline int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len,
+			       u32 dst)
+{
+	/* This shouldn't be possible */
+	WARN_ON(1);
+
+	return -ENXIO;
+
+}
+
+static inline int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src,
+					u32 dst, void *data, int len)
+{
+	/* This shouldn't be possible */
+	WARN_ON(1);
+
+	return -ENXIO;
+}
+
+static inline int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len)
+{
+	/* This shouldn't be possible */
+	WARN_ON(1);
+
+	return -ENXIO;
+}
+
+static inline int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data,
+				  int len, u32 dst)
+{
+	/* This shouldn't be possible */
+	WARN_ON(1);
+
+	return -ENXIO;
+}
+
+static inline int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src,
+					   u32 dst, void *data, int len)
+{
+	/* 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 */
 #define register_rpmsg_driver(drv) \
 	__register_rpmsg_driver(drv, THIS_MODULE)
@@ -157,14 +272,4 @@ struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_device *,
 	module_driver(__rpmsg_driver, register_rpmsg_driver, \
 			unregister_rpmsg_driver)
 
-int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len);
-int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst);
-int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
-			  void *data, int len);
-
-int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len);
-int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst);
-int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
-			     void *data, int len);
-
 #endif /* _LINUX_RPMSG_H */