rpmsg_virtio: configuration option to set buffer sizes per instance

lib/include/openamp/rpmsg_virtio.h

@@ -41,9 +41,31 @@ struct rpmsg_virtio_shm_pool {
 	size_t size;
 };
 
+/**
+ * struct rpmsg_virtio_config - configuration of rpmsg device based on virtio
+ *
+ * This structure is used by the rpmsg virtio host to configure the virtiio
+ * layer.
+ *
+ * @h2r_buf_size: the size of the buffer used to send data from host to remote
+ * @r2h_buf_size: the size of the buffer used to send data from remote to host
+ */
+struct rpmsg_virtio_config {
+	uint32_t h2r_buf_size;
+	uint32_t r2h_buf_size;
+};
+
+/* Default configuration */
+#define RPMSG_VIRTIO_DEFAULT_CONFIG                \
+	((const struct rpmsg_virtio_config) {       \
+		.h2r_buf_size = RPMSG_BUFFER_SIZE,  \
+		.r2h_buf_size = RPMSG_BUFFER_SIZE,  \
+	})
+
 /**
  * struct rpmsg_virtio_device - representation of a rpmsg device based on virtio
  * @rdev: rpmsg device, first property in the struct
+ * @config: structure containing virtio configuration
  * @vdev: pointer to the virtio device
  * @rvq: pointer to receive virtqueue
  * @svq: pointer to send virtqueue
@@ -52,6 +74,7 @@ struct rpmsg_virtio_shm_pool {
  */
 struct rpmsg_virtio_device {
 	struct rpmsg_device rdev;
+	struct rpmsg_virtio_config config;
 	struct virtio_device *vdev;
 	struct virtqueue *rvq;
 	struct virtqueue *svq;
@@ -120,14 +143,14 @@ int rpmsg_virtio_get_buffer_size(struct rpmsg_device *rdev);
 
 /**
  * rpmsg_init_vdev - initialize rpmsg virtio device
- * Master side:
+ * Host side:
  * Initialize RPMsg virtio queues and shared buffers, the address of shm can be
  * ANY. In this case, function will get shared memory from system shared memory
- * pools. If the vdev has RPMsg name service feature, this API will create an
+ * pools. If the vdev has the RPMsg name service feature, this API will create a
  * name service endpoint.
  *
- * Slave side:
- * This API will not return until the driver ready is set by the master side.
+ * Remote side:
+ * This API will not return until the driver ready is set by the host side.
  *
  * @param rvdev  - pointer to the rpmsg virtio device
  * @param vdev   - pointer to the virtio device
@@ -145,6 +168,39 @@ int rpmsg_init_vdev(struct rpmsg_virtio_device *rvdev,
 		    struct metal_io_region *shm_io,
 		    struct rpmsg_virtio_shm_pool *shpool);
 
+/**
+ * rpmsg_init_vdev_with_config - initialize rpmsg virtio device with config
+ * Host side:
+ * Initialize RPMsg virtio queues and shared buffers, the address of shm can be
+ * ANY. In this case, function will get shared memory from system shared memory
+ * pools. If the vdev has the RPMsg name service feature, this API will create a
+ * name service endpoint.
+ * Sizes of virtio data buffers used by the initialized RPMsg instance are set
+ * to values read from the passed configuration structure.
+ *
+ * Remote side:
+ * This API will not return until the driver ready is set by the host side.
+ * Sizes of virtio data buffers are set by the host side. Values passed in the
+ * configuration structure have no effect.
+ *
+ * @param rvdev  - pointer to the rpmsg virtio device
+ * @param vdev   - pointer to the virtio device
+ * @param ns_bind_cb  - callback handler for name service announcement without
+ *                      local endpoints waiting to bind.
+ * @param shm_io - pointer to the share memory I/O region.
+ * @param shpool - pointer to shared memory pool. rpmsg_virtio_init_shm_pool has
+ *                 to be called first to fill this structure.
+ * @param config - pointer to configuration structure
+ *
+ * @return - status of function execution
+ */
+int rpmsg_init_vdev_with_config(struct rpmsg_virtio_device *rvdev,
+				struct virtio_device *vdev,
+				rpmsg_ns_bind_cb ns_bind_cb,
+				struct metal_io_region *shm_io,
+				struct rpmsg_virtio_shm_pool *shpool,
+				const struct rpmsg_virtio_config *config);
+
 /**
  * rpmsg_deinit_vdev - deinitialize rpmsg virtio device
  *

lib/rpmsg/rpmsg_virtio.c

@@ -3,6 +3,7 @@
  * All rights reserved.
  * Copyright (c) 2016 Freescale Semiconductor, Inc. All rights reserved.
  * Copyright (c) 2018 Linaro, Inc. All rights reserved.
+ * Copyright (c) 2021 Nordic Semiconductor ASA
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -151,8 +152,8 @@ static void *rpmsg_virtio_get_tx_buffer(struct rpmsg_virtio_device *rvdev,
 		data = virtqueue_get_buffer(rvdev->svq, len, idx);
 		if (!data && rvdev->svq->vq_free_cnt) {
 			data = rpmsg_virtio_shm_pool_get_buffer(rvdev->shpool,
-							RPMSG_BUFFER_SIZE);
-			*len = RPMSG_BUFFER_SIZE;
+					rvdev->config.h2r_buf_size);
+			*len = rvdev->config.h2r_buf_size;
 			*idx = 0;
 		}
 	}
@@ -250,7 +251,7 @@ static int _rpmsg_virtio_get_buffer_size(struct rpmsg_virtio_device *rvdev)
 		 * If device role is Master then buffers are provided by us,
 		 * so just provide the macro.
 		 */
-		length = RPMSG_BUFFER_SIZE - sizeof(struct rpmsg_hdr);
+		length = rvdev->config.h2r_buf_size - sizeof(struct rpmsg_hdr);
 	}
 #endif /*!VIRTIO_SLAVE_ONLY*/
 
@@ -384,7 +385,7 @@ static int rpmsg_virtio_send_offchannel_nocopy(struct rpmsg_device *rdev,
 
 #ifndef VIRTIO_SLAVE_ONLY
 	if (rpmsg_virtio_get_role(rvdev) == RPMSG_MASTER)
-		buff_len = RPMSG_BUFFER_SIZE;
+		buff_len = rvdev->config.h2r_buf_size;
 	else
 #endif /*!VIRTIO_SLAVE_ONLY*/
 		buff_len = virtqueue_get_buffer_length(rvdev->svq, idx);
@@ -610,6 +611,17 @@ int rpmsg_init_vdev(struct rpmsg_virtio_device *rvdev,
 		    rpmsg_ns_bind_cb ns_bind_cb,
 		    struct metal_io_region *shm_io,
 		    struct rpmsg_virtio_shm_pool *shpool)
+{
+	return rpmsg_init_vdev_with_config(rvdev, vdev, ns_bind_cb, shm_io,
+			   shpool, &RPMSG_VIRTIO_DEFAULT_CONFIG);
+}
+
+int rpmsg_init_vdev_with_config(struct rpmsg_virtio_device *rvdev,
+				struct virtio_device *vdev,
+				rpmsg_ns_bind_cb ns_bind_cb,
+				struct metal_io_region *shm_io,
+				struct rpmsg_virtio_shm_pool *shpool,
+				const struct rpmsg_virtio_config *config)
 {
 	struct rpmsg_device *rdev;
 	const char *vq_names[RPMSG_NUM_VRINGS];
@@ -630,6 +642,23 @@ int rpmsg_init_vdev(struct rpmsg_virtio_device *rvdev,
 	rdev->ops.send_offchannel_nocopy = rpmsg_virtio_send_offchannel_nocopy;
 	role = rpmsg_virtio_get_role(rvdev);
 
+#ifndef VIRTIO_SLAVE_ONLY
+	if (role == RPMSG_MASTER) {
+		/*
+		 * The virtio configuration contains only options applicable to
+		 * a virtio driver, implying rpmsg host role.
+		 */
+		if (config == NULL) {
+			return RPMSG_ERR_PARAM;
+		}
+		rvdev->config = *config;
+	}
+#else /*!VIRTIO_SLAVE_ONLY*/
+	/* Ignore passed config in the virtio-device-only configuration. */
+	(void)config;
+#endif /*!VIRTIO_SLAVE_ONLY*/
+
+
 #ifndef VIRTIO_MASTER_ONLY
 	if (role == RPMSG_REMOTE) {
 		/* wait synchro with the master */
@@ -699,11 +728,11 @@ int rpmsg_init_vdev(struct rpmsg_virtio_device *rvdev,
 		unsigned int idx;
 		void *buffer;
 
-		vqbuf.len = RPMSG_BUFFER_SIZE;
+		vqbuf.len = rvdev->config.r2h_buf_size;
 		for (idx = 0; idx < rvdev->rvq->vq_nentries; idx++) {
 			/* Initialize TX virtqueue buffers for remote device */
 			buffer = rpmsg_virtio_shm_pool_get_buffer(shpool,
-							RPMSG_BUFFER_SIZE);
+					rvdev->config.r2h_buf_size);
 
 			if (!buffer) {
 				return RPMSG_ERR_NO_BUFF;
@@ -714,7 +743,7 @@ int rpmsg_init_vdev(struct rpmsg_virtio_device *rvdev,
 			metal_io_block_set(shm_io,
 					   metal_io_virt_to_offset(shm_io,
 								   buffer),
-					   0x00, RPMSG_BUFFER_SIZE);
+					   0x00, rvdev->config.r2h_buf_size);
 			status =
 				virtqueue_add_buffer(rvdev->rvq, &vqbuf, 0, 1,
 						     buffer);