implement rproc_virtio_read_config/rproc_virtio_write_config

so the rpmsg could access the configuration space as needed

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>

Author: xiaoxiang781216

lib/include/openamp/virtio.h

@@ -100,6 +100,7 @@ struct virtio_device {
 	virtio_dev_reset_cb reset_cb; /**< user registered device callback */
 	const struct virtio_dispatch *func; /**< Virtio dispatch table */
 	void *priv; /**< TODO: remove pointer to virtio_device private data */
+	unsigned int config_len;  /**< config space length */
 	unsigned int vrings_num; /**< number of vrings */
 	struct virtio_vring_info *vrings_info;
 };

lib/remoteproc/remoteproc_virtio.c

@@ -126,20 +126,37 @@ static uint32_t rproc_virtio_negotiate_features(struct virtio_device *vdev,
 static void rproc_virtio_read_config(struct virtio_device *vdev,
 				     uint32_t offset, void *dst, int length)
 {
-	(void)vdev;
-	(void)offset;
-	(void)dst;
-	(void)length;
+	struct remoteproc_virtio *rpvdev;
+	struct fw_rsc_vdev *vdev_rsc;
+	struct metal_io_region *io;
+	char *config;
+
+	rpvdev = metal_container_of(vdev, struct remoteproc_virtio, vdev);
+	vdev_rsc = rpvdev->vdev_rsc;
+	config = (char *)(&vdev_rsc->vring[vdev->vrings_num]);
+	io = rpvdev->vdev_rsc_io;
+	metal_io_block_read(io,
+			    metal_io_virt_to_offset(io, config + offset),
+			    dst, length);
 }
 
 #ifndef VIRTIO_SLAVE_ONLY
 static void rproc_virtio_write_config(struct virtio_device *vdev,
 				      uint32_t offset, void *src, int length)
 {
-	(void)vdev;
-	(void)offset;
-	(void)src;
-	(void)length;
+	struct remoteproc_virtio *rpvdev;
+	struct fw_rsc_vdev *vdev_rsc;
+	struct metal_io_region *io;
+	char *config;
+
+	rpvdev = metal_container_of(vdev, struct remoteproc_virtio, vdev);
+	vdev_rsc = rpvdev->vdev_rsc;
+	config = (char *)(&vdev_rsc->vring[vdev->vrings_num]);
+	io = rpvdev->vdev_rsc_io;
+	metal_io_block_write(io,
+			    metal_io_virt_to_offset(io, config + offset),
+			    src, length);
+	rpvdev->notify(rpvdev->priv, vdev->notifyid);
 }
 
 static void rproc_virtio_reset_device(struct virtio_device *vdev)
@@ -220,6 +237,7 @@ rproc_virtio_create_vdev(unsigned int role, unsigned int notifyid,
 	vdev->notifyid = notifyid;
 	vdev->role = role;
 	vdev->reset_cb = rst_cb;
+	vdev->config_len = vdev_rsc->config_len;
 	vdev->vrings_num = num_vrings;
 	vdev->func = &remoteproc_virtio_dispatch_funcs;