remoteproc: support virtio config space.

Support virtio configuration space and device status. The virtio
device can now access the resource table in shared memory.

Signed-off-by: Sjur Brændeland <[e-mail]>
Acked-by: Ido Yariv <[e-mail]>
[rebase and style changes]
Signed-off-by: Ohad Ben-Cohen <[e-mail]>

drivers/remoteproc/remoteproc_core.c

···
 			goto free_rvdev;
 	}
 
-	/* remember the device features */
-	rvdev->dfeatures = rsc->dfeatures;
-
 	/* remember the resource offset*/
 	rvdev->rsc_offset = offset;
 

drivers/remoteproc/remoteproc_virtio.c

···
 	return ret;
 }
 
-/*
- * We don't support yet real virtio status semantics.
- *
- * The plan is to provide this via the VDEV resource entry
- * which is part of the firmware: this way the remote processor
- * will be able to access the status values as set by us.
- */
 static u8 rproc_virtio_get_status(struct virtio_device *vdev)
 {
-	return 0;
+	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
+	struct fw_rsc_vdev *rsc;
+
+	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
+
+	return rsc->status;
 }
 
 static void rproc_virtio_set_status(struct virtio_device *vdev, u8 status)
 {
+	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
+	struct fw_rsc_vdev *rsc;
+
+	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
+
+	rsc->status = status;
 	dev_dbg(&vdev->dev, "status: %d\n", status);
 }
 
 static void rproc_virtio_reset(struct virtio_device *vdev)
 {
+	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
+	struct fw_rsc_vdev *rsc;
+
+	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
+
+	rsc->status = 0;
 	dev_dbg(&vdev->dev, "reset !\n");
 }
 
···
 static u32 rproc_virtio_get_features(struct virtio_device *vdev)
 {
 	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
+	struct fw_rsc_vdev *rsc;
 
-	return rvdev->dfeatures;
+	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
+
+	return rsc->dfeatures;
 }
 
 static void rproc_virtio_finalize_features(struct virtio_device *vdev)
 {
 	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
+	struct fw_rsc_vdev *rsc;
+
+	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
 
 	/* Give virtio_ring a chance to accept features */
 	vring_transport_features(vdev);
···
 	/*
 	 * Remember the finalized features of our vdev, and provide it
 	 * to the remote processor once it is powered on.
-	 *
-	 * Similarly to the status field, we don't expose yet the negotiated
-	 * features to the remote processors at this point. This will be
-	 * fixed as part of a small resource table overhaul and then an
-	 * extension of the virtio resource entries.
 	 */
-	rvdev->gfeatures = vdev->features[0];
+	rsc->gfeatures = vdev->features[0];
+}
+
+static void rproc_virtio_get(struct virtio_device *vdev, unsigned offset,
+							void *buf, unsigned len)
+{
+	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
+	struct fw_rsc_vdev *rsc;
+	void *cfg;
+
+	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
+	cfg = &rsc->vring[rsc->num_of_vrings];
+
+	if (offset + len > rsc->config_len || offset + len < len) {
+		dev_err(&vdev->dev, "rproc_virtio_get: access out of bounds\n");
+		return;
+	}
+
+	memcpy(buf, cfg + offset, len);
+}
+
+static void rproc_virtio_set(struct virtio_device *vdev, unsigned offset,
+		      const void *buf, unsigned len)
+{
+	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
+	struct fw_rsc_vdev *rsc;
+	void *cfg;
+
+	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
+	cfg = &rsc->vring[rsc->num_of_vrings];
+
+	if (offset + len > rsc->config_len || offset + len < len) {
+		dev_err(&vdev->dev, "rproc_virtio_set: access out of bounds\n");
+		return;
+	}
+
+	memcpy(cfg + offset, buf, len);
 }
 
 static const struct virtio_config_ops rproc_virtio_config_ops = {
···
 	.reset		= rproc_virtio_reset,
 	.set_status	= rproc_virtio_set_status,
 	.get_status	= rproc_virtio_get_status,
+	.get		= rproc_virtio_get,
+	.set		= rproc_virtio_set,
 };
 
 /*

include/linux/remoteproc.h

···
  * @rproc: the rproc handle
  * @vdev: the virio device
  * @vring: the vrings for this vdev
- * @dfeatures: virtio device features
- * @gfeatures: virtio guest features
  * @rsc_offset: offset of the vdev's resource entry
  */
 struct rproc_vdev {
···
 	struct rproc *rproc;
 	struct virtio_device vdev;
 	struct rproc_vring vring[RVDEV_NUM_VRINGS];
-	unsigned long dfeatures;
-	unsigned long gfeatures;
 	u32 rsc_offset;
 };