/*
 * Remoteproc Virtio Framework Implementation
 *
 * Copyright(c) 2018 Xilinx Ltd.
 * Copyright(c) 2011 Texas Instruments, Inc.
 * Copyright(c) 2011 Google, Inc.
 * All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <openamp/remoteproc.h>
#include <openamp/remoteproc_virtio.h>
#include <openamp/virtqueue.h>
#include <metal/sys.h>
#include <metal/utilities.h>
#include <metal/alloc.h>

static void rproc_virtio_delete_virtqueues(struct virtio_device *vdev)
{
	struct virtio_vring_info *vring_info;
	unsigned int i;

	if (!vdev->vrings_info)
		return;

	for (i = 0; i < vdev->vrings_num; i++) {
		vring_info = &vdev->vrings_info[i];
		if (vring_info->vq)
			virtqueue_free(vring_info->vq);
	}
}

static int rproc_virtio_create_virtqueue(struct virtio_device *vdev,
					 unsigned int flags,
					 unsigned int idx,
					 const char *name,
					 vq_callback callback)
{
	struct virtio_vring_info *vring_info;
	struct vring_alloc_info *vring_alloc;
	int ret;
	(void)flags;

	/* Get the vring information */
	vring_info = &vdev->vrings_info[idx];
	vring_alloc = &vring_info->info;

	/* Fail if the virtqueue has already been created */
	if (vring_info->vq)
		return ERROR_VQUEUE_INVLD_PARAM;

	/* Alloc the virtqueue and init it */
	vring_info->vq = virtqueue_allocate(vring_alloc->num_descs);
	if (!vring_info->vq)
		return ERROR_NO_MEM;

	if (VIRTIO_ROLE_IS_DRIVER(vdev)) {
		size_t offset = metal_io_virt_to_offset(vring_info->io, vring_alloc->vaddr);
		size_t size = vring_size(vring_alloc->num_descs, vring_alloc->align);

		metal_io_block_set(vring_info->io, offset, 0, size);
	}

	ret = virtqueue_create(vdev, idx, name, vring_alloc, callback,
			       vdev->func->notify, vring_info->vq);
	if (ret)
		return ret;

	return 0;
}

static int rproc_virtio_create_virtqueues(struct virtio_device *vdev,
					  unsigned int flags,
					  unsigned int nvqs,
					  const char *names[],
					  vq_callback callbacks[],
					  void *callback_args[])
{
	unsigned int i;
	int ret;
	(void)callback_args;

	/* Check virtqueue numbers and the vrings_info */
	if (nvqs > vdev->vrings_num || !vdev || !vdev->vrings_info)
		return ERROR_VQUEUE_INVLD_PARAM;

	/* set the notification id for vrings */
	for (i = 0; i < nvqs; i++) {
		ret = rproc_virtio_create_virtqueue(vdev, flags, i, names[i], callbacks[i]);
		if (ret)
			goto err;
	}
	return 0;

err:
	rproc_virtio_delete_virtqueues(vdev);
	return ret;
}

static void rproc_virtio_virtqueue_notify(struct virtqueue *vq)
{
	struct remoteproc_virtio *rpvdev;
	struct virtio_vring_info *vring_info;
	struct virtio_device *vdev;
	unsigned int vq_id = vq->vq_queue_index;

	vdev = vq->vq_dev;
	rpvdev = metal_container_of(vdev, struct remoteproc_virtio, vdev);
	metal_assert(vq_id < vdev->vrings_num);
	vring_info = &vdev->vrings_info[vq_id];
	rpvdev->notify(rpvdev->priv, vring_info->notifyid);
}

static unsigned char rproc_virtio_get_status(struct virtio_device *vdev)
{
	struct remoteproc_virtio *rpvdev;
	struct fw_rsc_vdev *vdev_rsc;
	struct metal_io_region *io;
	char status;

	rpvdev = metal_container_of(vdev, struct remoteproc_virtio, vdev);
	vdev_rsc = rpvdev->vdev_rsc;
	io = rpvdev->vdev_rsc_io;
	RSC_TABLE_INVALIDATE(vdev_rsc, sizeof(struct fw_rsc_vdev));
	status = metal_io_read8(io,
				metal_io_virt_to_offset(io, &vdev_rsc->status));
	return status;
}

#if VIRTIO_ENABLED(VIRTIO_DRIVER_SUPPORT)
static void rproc_virtio_set_status(struct virtio_device *vdev,
				    unsigned char status)
{
	struct remoteproc_virtio *rpvdev;
	struct fw_rsc_vdev *vdev_rsc;
	struct metal_io_region *io;

	rpvdev = metal_container_of(vdev, struct remoteproc_virtio, vdev);
	vdev_rsc = rpvdev->vdev_rsc;
	io = rpvdev->vdev_rsc_io;
	metal_io_write8(io,
			metal_io_virt_to_offset(io, &vdev_rsc->status),
			status);
	RSC_TABLE_FLUSH(vdev_rsc, sizeof(struct fw_rsc_vdev));
	rpvdev->notify(rpvdev->priv, vdev->notifyid);
}
#endif

static uint32_t rproc_virtio_get_dfeatures(struct virtio_device *vdev)
{
	struct remoteproc_virtio *rpvdev;
	struct fw_rsc_vdev *vdev_rsc;
	struct metal_io_region *io;
	uint32_t features;

	rpvdev = metal_container_of(vdev, struct remoteproc_virtio, vdev);
	vdev_rsc = rpvdev->vdev_rsc;
	io = rpvdev->vdev_rsc_io;
	RSC_TABLE_INVALIDATE(vdev_rsc, sizeof(struct fw_rsc_vdev));
	features = metal_io_read32(io,
			metal_io_virt_to_offset(io, &vdev_rsc->dfeatures));

	return features;
}

static uint32_t rproc_virtio_get_features(struct virtio_device *vdev)
{
	struct remoteproc_virtio *rpvdev;
	struct fw_rsc_vdev *vdev_rsc;
	struct metal_io_region *io;
	uint32_t gfeatures;
	uint32_t dfeatures;

	rpvdev = metal_container_of(vdev, struct remoteproc_virtio, vdev);
	vdev_rsc = rpvdev->vdev_rsc;
	io = rpvdev->vdev_rsc_io;
	RSC_TABLE_INVALIDATE(vdev_rsc, sizeof(struct fw_rsc_vdev));
	gfeatures = metal_io_read32(io,
			metal_io_virt_to_offset(io, &vdev_rsc->gfeatures));
	dfeatures = rproc_virtio_get_dfeatures(vdev);

	return dfeatures & gfeatures;
}

#if VIRTIO_ENABLED(VIRTIO_DRIVER_SUPPORT)
static void rproc_virtio_set_features(struct virtio_device *vdev,
				      uint32_t features)
{
	struct remoteproc_virtio *rpvdev;
	struct fw_rsc_vdev *vdev_rsc;
	struct metal_io_region *io;

	rpvdev = metal_container_of(vdev, struct remoteproc_virtio, vdev);
	vdev_rsc = rpvdev->vdev_rsc;
	io = rpvdev->vdev_rsc_io;
	metal_io_write32(io,
			 metal_io_virt_to_offset(io, &vdev_rsc->gfeatures),
			 features);
	RSC_TABLE_FLUSH(vdev_rsc, sizeof(struct fw_rsc_vdev));
	rpvdev->notify(rpvdev->priv, vdev->notifyid);
}

static uint32_t rproc_virtio_negotiate_features(struct virtio_device *vdev,
						uint32_t features)
{
	features = features & rproc_virtio_get_dfeatures(vdev);
	rproc_virtio_set_features(vdev, features);

	/* return the mask of features successfully negotiated */
	return features;
}
#endif

static void rproc_virtio_read_config(struct virtio_device *vdev,
				     uint32_t offset, void *dst, int 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;

	if (offset + length <= vdev_rsc->config_len) {
		RSC_TABLE_INVALIDATE(config + offset, length);
		metal_io_block_read(io,
				metal_io_virt_to_offset(io, config + offset),
				dst, length);
	}
}

#if VIRTIO_ENABLED(VIRTIO_DRIVER_SUPPORT)
static void rproc_virtio_write_config(struct virtio_device *vdev,
				      uint32_t offset, void *src, int 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;

	if (offset + length <= vdev_rsc->config_len) {
		metal_io_block_write(io,
				metal_io_virt_to_offset(io, config + offset),
				src, length);
		RSC_TABLE_FLUSH(config + offset, length);
		rpvdev->notify(rpvdev->priv, vdev->notifyid);
	}
}

static void rproc_virtio_reset_device(struct virtio_device *vdev)
{
	if (vdev->role == VIRTIO_DEV_DRIVER)
		rproc_virtio_set_status(vdev,
					VIRTIO_CONFIG_STATUS_NEEDS_RESET);
}
#endif

static const struct virtio_dispatch remoteproc_virtio_dispatch_funcs = {
	.create_virtqueues = rproc_virtio_create_virtqueues,
	.delete_virtqueues = rproc_virtio_delete_virtqueues,
	.get_status = rproc_virtio_get_status,
	.get_features = rproc_virtio_get_features,
	.read_config = rproc_virtio_read_config,
	.notify = rproc_virtio_virtqueue_notify,
#if VIRTIO_ENABLED(VIRTIO_DRIVER_SUPPORT)
	/*
	 * We suppose here that the vdev is in a shared memory so that can
	 * be access only by one core: the host. In this case salve core has
	 * only read access right.
	 */
	.set_status = rproc_virtio_set_status,
	.set_features = rproc_virtio_set_features,
	.negotiate_features = rproc_virtio_negotiate_features,
	.write_config = rproc_virtio_write_config,
	.reset_device = rproc_virtio_reset_device,
#endif
};

struct virtio_device *
rproc_virtio_create_vdev(unsigned int role, unsigned int notifyid,
			 void *rsc, struct metal_io_region *rsc_io,
			 void *priv,
			 rpvdev_notify_func notify,
			 virtio_dev_reset_cb rst_cb)
{
	struct remoteproc_virtio *rpvdev;
	struct virtio_vring_info *vrings_info;
	struct fw_rsc_vdev *vdev_rsc = rsc;
	struct virtio_device *vdev;
	unsigned int num_vrings = vdev_rsc->num_of_vrings;

	rpvdev = metal_allocate_memory(sizeof(*rpvdev));
	if (!rpvdev)
		return NULL;
	vrings_info = metal_allocate_memory(sizeof(*vrings_info) * num_vrings);
	if (!vrings_info)
		goto err;
	memset(rpvdev, 0, sizeof(*rpvdev));
	memset(vrings_info, 0, sizeof(*vrings_info) * num_vrings);

	/* Initialize the remoteproc virtio */
	rpvdev->notify = notify;
	rpvdev->priv = priv;
	/* Assuming the shared memory has been mapped and registered if
	 * necessary
	 */
	rpvdev->vdev_rsc = vdev_rsc;
	rpvdev->vdev_rsc_io = rsc_io;

	/* Initialize the virtio device */
	vdev = &rpvdev->vdev;
	vdev->vrings_info = vrings_info;
	vdev->notifyid = notifyid;
	vdev->id.device = vdev_rsc->id;
	vdev->role = role;
	vdev->reset_cb = rst_cb;
	vdev->vrings_num = num_vrings;
	vdev->func = &remoteproc_virtio_dispatch_funcs;

#if VIRTIO_ENABLED(VIRTIO_DRIVER_SUPPORT)
	if (role == VIRTIO_DEV_DRIVER) {
		uint32_t dfeatures = rproc_virtio_get_dfeatures(vdev);
		/* Assume the virtio driver support all remote features */
		rproc_virtio_negotiate_features(vdev, dfeatures);
	}
#endif

	return &rpvdev->vdev;
err:
	metal_free_memory(rpvdev);
	return NULL;
}

void rproc_virtio_remove_vdev(struct virtio_device *vdev)
{
	struct remoteproc_virtio *rpvdev;

	if (!vdev)
		return;
	rpvdev = metal_container_of(vdev, struct remoteproc_virtio, vdev);
	if (vdev->vrings_info)
		metal_free_memory(vdev->vrings_info);
	metal_free_memory(rpvdev);
}

int rproc_virtio_init_vring(struct virtio_device *vdev, unsigned int index,
			    unsigned int notifyid, void *va,
			    struct metal_io_region *io,
			    unsigned int num_descs, unsigned int align)
{
	struct virtio_vring_info *vring_info;
	unsigned int num_vrings;

	num_vrings = vdev->vrings_num;
	if ((index >= num_vrings) || (num_descs > RPROC_MAX_VRING_DESC))
		return -RPROC_EINVAL;
	vring_info = &vdev->vrings_info[index];
	vring_info->io = io;
	vring_info->notifyid = notifyid;
	vring_info->info.vaddr = va;
	vring_info->info.num_descs = num_descs;
	vring_info->info.align = align;

	return 0;
}

int rproc_virtio_notified(struct virtio_device *vdev, uint32_t notifyid)
{
	unsigned int num_vrings, i;
	struct virtio_vring_info *vring_info;
	struct virtqueue *vq;

	if (!vdev)
		return -RPROC_EINVAL;
	/* We do nothing for vdev notification in this implementation */
	if (vdev->notifyid == notifyid)
		return 0;
	num_vrings = vdev->vrings_num;
	for (i = 0; i < num_vrings; i++) {
		vring_info = &vdev->vrings_info[i];
		if (vring_info->notifyid == notifyid ||
		    notifyid == RSC_NOTIFY_ID_ANY) {
			vq = vring_info->vq;
			virtqueue_notification(vq);
		}
	}
	return 0;
}

void rproc_virtio_wait_remote_ready(struct virtio_device *vdev)
{
	uint8_t status;

	/*
	 * No status available for remote. As virtio driver has not to wait
	 * remote action, we can return. Behavior should be updated
	 * in future if a remote status is added.
	 */
	if (VIRTIO_ROLE_IS_DRIVER(vdev))
		return;

	while (1) {
		status = rproc_virtio_get_status(vdev);
		if (status & VIRTIO_CONFIG_STATUS_DRIVER_OK)
			return;
		metal_yield();
	}
}