rpmsg updates for v5.13

In addition to some bug fixes and cleanups this adds support for
 exposing the virtio based transport to user space using the rpmsg_char
 driver.
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Merge tag 'rpmsg-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/andersson/remoteproc

Pull rpmsg updates from Bjorn Andersson:
 "In addition to some bug fixes and cleanups this adds support for
  exposing the virtio based transport to user space using the rpmsg_char
  driver"

* tag 'rpmsg-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/andersson/remoteproc:
  rpmsg: qcom_glink_native: fix error return code of qcom_glink_rx_data()
  rpmsg: char: Return an error if device already open
  rpmsg: virtio: Register the rpmsg_char device
  rpmsg: char: Use rpmsg_sendto to specify the message destination address
  rpmsg: Add short description of the IOCTL defined in UAPI.
  rpmsg: Move RPMSG_ADDR_ANY in user API
  rpmsg: char: Rename rpmsg_char_init to rpmsg_chrdev_init

drivers/rpmsg/qcom_glink_native.c

@@ -857,6 +857,7 @@ static int qcom_glink_rx_data(struct qcom_glink *glink, size_t avail)
 			dev_err(glink->dev,
 				"no intent found for channel %s intent %d",
 				channel->name, liid);
+			ret = -ENOENT;
 			goto advance_rx;
 		}
 	}
@@ -1332,6 +1333,20 @@ static int qcom_glink_trysend(struct rpmsg_endpoint *ept, void *data, int len)
 	return __qcom_glink_send(channel, data, len, false);
 }
 
+static int qcom_glink_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
+{
+	struct glink_channel *channel = to_glink_channel(ept);
+
+	return __qcom_glink_send(channel, data, len, true);
+}
+
+static int qcom_glink_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
+{
+	struct glink_channel *channel = to_glink_channel(ept);
+
+	return __qcom_glink_send(channel, data, len, false);
+}
+
 /*
  * Finds the device_node for the glink child interested in this channel.
  */
@@ -1364,7 +1379,9 @@ static const struct rpmsg_device_ops glink_device_ops = {
 static const struct rpmsg_endpoint_ops glink_endpoint_ops = {
 	.destroy_ept = qcom_glink_destroy_ept,
 	.send = qcom_glink_send,
+	.sendto = qcom_glink_sendto,
 	.trysend = qcom_glink_trysend,
+	.trysendto = qcom_glink_trysendto,
 };
 
 static void qcom_glink_rpdev_release(struct device *dev)

drivers/rpmsg/qcom_smd.c

@@ -974,6 +974,20 @@ static int qcom_smd_trysend(struct rpmsg_endpoint *ept, void *data, int len)
 	return __qcom_smd_send(qsept->qsch, data, len, false);
 }
 
+static int qcom_smd_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
+{
+	struct qcom_smd_endpoint *qsept = to_smd_endpoint(ept);
+
+	return __qcom_smd_send(qsept->qsch, data, len, true);
+}
+
+static int qcom_smd_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
+{
+	struct qcom_smd_endpoint *qsept = to_smd_endpoint(ept);
+
+	return __qcom_smd_send(qsept->qsch, data, len, false);
+}
+
 static __poll_t qcom_smd_poll(struct rpmsg_endpoint *ept,
 				  struct file *filp, poll_table *wait)
 {
@@ -1038,7 +1052,9 @@ static const struct rpmsg_device_ops qcom_smd_device_ops = {
 static const struct rpmsg_endpoint_ops qcom_smd_endpoint_ops = {
 	.destroy_ept = qcom_smd_destroy_ept,
 	.send = qcom_smd_send,
+	.sendto = qcom_smd_sendto,
 	.trysend = qcom_smd_trysend,
+	.trysendto = qcom_smd_trysendto,
 	.poll = qcom_smd_poll,
 };
 

drivers/rpmsg/rpmsg_char.c

@@ -127,6 +127,9 @@ static int rpmsg_eptdev_open(struct inode *inode, struct file *filp)
 	struct rpmsg_device *rpdev = eptdev->rpdev;
 	struct device *dev = &eptdev->dev;
 
+	if (eptdev->ept)
+		return -EBUSY;
+
 	get_device(dev);
 
 	ept = rpmsg_create_ept(rpdev, rpmsg_ept_cb, eptdev, eptdev->chinfo);
@@ -239,9 +242,9 @@ static ssize_t rpmsg_eptdev_write_iter(struct kiocb *iocb,
 	}
 
 	if (filp->f_flags & O_NONBLOCK)
-		ret = rpmsg_trysend(eptdev->ept, kbuf, len);
+		ret = rpmsg_trysendto(eptdev->ept, kbuf, len, eptdev->chinfo.dst);
 	else
-		ret = rpmsg_send(eptdev->ept, kbuf, len);
+		ret = rpmsg_sendto(eptdev->ept, kbuf, len, eptdev->chinfo.dst);
 
 unlock_eptdev:
 	mutex_unlock(&eptdev->ept_lock);
@@ -543,7 +546,7 @@ static struct rpmsg_driver rpmsg_chrdev_driver = {
 	},
 };
 
-static int rpmsg_char_init(void)
+static int rpmsg_chrdev_init(void)
 {
 	int ret;
 
@@ -569,7 +572,7 @@ static int rpmsg_char_init(void)
 
 	return ret;
 }
-postcore_initcall(rpmsg_char_init);
+postcore_initcall(rpmsg_chrdev_init);
 
 static void rpmsg_chrdev_exit(void)
 {

drivers/rpmsg/virtio_rpmsg_bus.c

@@ -813,14 +813,57 @@ static void rpmsg_xmit_done(struct virtqueue *svq)
 	wake_up_interruptible(&vrp->sendq);
 }
 
+/*
+ * Called to expose to user a /dev/rpmsg_ctrlX interface allowing to
+ * create endpoint-to-endpoint communication without associated RPMsg channel.
+ * The endpoints are rattached to the ctrldev RPMsg device.
+ */
+static struct rpmsg_device *rpmsg_virtio_add_ctrl_dev(struct virtio_device *vdev)
+{
+	struct virtproc_info *vrp = vdev->priv;
+	struct virtio_rpmsg_channel *vch;
+	struct rpmsg_device *rpdev_ctrl;
+	int err = 0;
+
+	vch = kzalloc(sizeof(*vch), GFP_KERNEL);
+	if (!vch)
+		return ERR_PTR(-ENOMEM);
+
+	/* Link the channel to the vrp */
+	vch->vrp = vrp;
+
+	/* Assign public information to the rpmsg_device */
+	rpdev_ctrl = &vch->rpdev;
+	rpdev_ctrl->ops = &virtio_rpmsg_ops;
+
+	rpdev_ctrl->dev.parent = &vrp->vdev->dev;
+	rpdev_ctrl->dev.release = virtio_rpmsg_release_device;
+	rpdev_ctrl->little_endian = virtio_is_little_endian(vrp->vdev);
+
+	err = rpmsg_chrdev_register_device(rpdev_ctrl);
+	if (err) {
+		kfree(vch);
+		return ERR_PTR(err);
+	}
+
+	return rpdev_ctrl;
+}
+
+static void rpmsg_virtio_del_ctrl_dev(struct rpmsg_device *rpdev_ctrl)
+{
+	if (!rpdev_ctrl)
+		return;
+	kfree(to_virtio_rpmsg_channel(rpdev_ctrl));
+}
+
 static int rpmsg_probe(struct virtio_device *vdev)
 {
 	vq_callback_t *vq_cbs[] = { rpmsg_recv_done, rpmsg_xmit_done };
 	static const char * const names[] = { "input", "output" };
 	struct virtqueue *vqs[2];
 	struct virtproc_info *vrp;
-	struct virtio_rpmsg_channel *vch;
-	struct rpmsg_device *rpdev_ns;
+	struct virtio_rpmsg_channel *vch = NULL;
+	struct rpmsg_device *rpdev_ns, *rpdev_ctrl;
 	void *bufs_va;
 	int err = 0, i;
 	size_t total_buf_space;
@@ -894,12 +937,18 @@ static int rpmsg_probe(struct virtio_device *vdev)
 
 	vdev->priv = vrp;
 
+	rpdev_ctrl = rpmsg_virtio_add_ctrl_dev(vdev);
+	if (IS_ERR(rpdev_ctrl)) {
+		err = PTR_ERR(rpdev_ctrl);
+		goto free_coherent;
+	}
+
 	/* if supported by the remote processor, enable the name service */
 	if (virtio_has_feature(vdev, VIRTIO_RPMSG_F_NS)) {
 		vch = kzalloc(sizeof(*vch), GFP_KERNEL);
 		if (!vch) {
 			err = -ENOMEM;
-			goto free_coherent;
+			goto free_ctrldev;
 		}
 
 		/* Link the channel to our vrp */
@@ -915,7 +964,7 @@ static int rpmsg_probe(struct virtio_device *vdev)
 
 		err = rpmsg_ns_register_device(rpdev_ns);
 		if (err)
-			goto free_coherent;
+			goto free_vch;
 	}
 
 	/*
@@ -939,8 +988,11 @@ static int rpmsg_probe(struct virtio_device *vdev)
 
 	return 0;
 
-free_coherent:
+free_vch:
 	kfree(vch);
+free_ctrldev:
+	rpmsg_virtio_del_ctrl_dev(rpdev_ctrl);
+free_coherent:
 	dma_free_coherent(vdev->dev.parent, total_buf_space,
 			  bufs_va, vrp->bufs_dma);
 vqs_del:

include/linux/rpmsg.h

@@ -18,8 +18,7 @@
 #include <linux/mutex.h>
 #include <linux/poll.h>
 #include <linux/rpmsg/byteorder.h>
-
-#define RPMSG_ADDR_ANY		0xFFFFFFFF
+#include <uapi/linux/rpmsg.h>
 
 struct rpmsg_device;
 struct rpmsg_endpoint;

include/uapi/linux/rpmsg.h

@@ -9,11 +9,13 @@
 #include <linux/ioctl.h>
 #include <linux/types.h>
 
+#define RPMSG_ADDR_ANY		0xFFFFFFFF
+
 /**
  * struct rpmsg_endpoint_info - endpoint info representation
  * @name: name of service
- * @src: local address
- * @dst: destination address
+ * @src: local address. To set to RPMSG_ADDR_ANY if not used.
+ * @dst: destination address. To set to RPMSG_ADDR_ANY if not used.
  */
 struct rpmsg_endpoint_info {
 	char name[32];
@@ -21,7 +23,14 @@ struct rpmsg_endpoint_info {
 	__u32 dst;
 };
 
+/**
+ * Instantiate a new rmpsg char device endpoint.
+ */
 #define RPMSG_CREATE_EPT_IOCTL	_IOW(0xb5, 0x1, struct rpmsg_endpoint_info)
+
+/**
+ * Destroy a rpmsg char device endpoint created by the RPMSG_CREATE_EPT_IOCTL.
+ */
 #define RPMSG_DESTROY_EPT_IOCTL	_IO(0xb5, 0x2)
 
 #endif