/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright (c) 2018, Microsoft Corporation.
 * All Rights Reserved.
 */

#include <fcntl.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/mman.h>

#include <rte_eal.h>
#include <rte_tailq.h>
#include <rte_log.h>
#include <rte_malloc.h>
#include <rte_bus.h>
#include <rte_bus_vmbus.h>

#include "private.h"

static struct rte_tailq_elem vmbus_tailq = {
	.name = "VMBUS_RESOURCE_LIST",
};
EAL_REGISTER_TAILQ(vmbus_tailq)

static int
vmbus_uio_map_secondary(struct rte_vmbus_device *dev)
{
	int fd, i;
	struct vmbus_channel *chan;
	struct mapped_vmbus_resource *uio_res;
	struct mapped_vmbus_res_list *uio_res_list
		= RTE_TAILQ_CAST(vmbus_tailq.head, mapped_vmbus_res_list);

	TAILQ_FOREACH(uio_res, uio_res_list, next) {

		/* skip this element if it doesn't match our UUID */
		if (rte_uuid_compare(uio_res->id, dev->device_id) != 0)
			continue;

		/* open /dev/uioX */
		fd = open(uio_res->path, O_RDWR);
		if (fd < 0) {
			VMBUS_LOG(ERR, "Cannot open %s: %s",
				  uio_res->path, strerror(errno));
			return -1;
		}

		for (i = 0; i != uio_res->nb_maps; i++) {
			void *mapaddr;
			off_t offset = i * PAGE_SIZE;

			mapaddr = vmbus_map_resource(uio_res->maps[i].addr,
						     fd, offset,
						     uio_res->maps[i].size, 0);

			if (mapaddr == uio_res->maps[i].addr)
				continue;

			VMBUS_LOG(ERR,
				  "Cannot mmap device resource file %s to address: %p",
				  uio_res->path, uio_res->maps[i].addr);

			if (mapaddr != MAP_FAILED)
				/* unmap addr wrongly mapped */
				vmbus_unmap_resource(mapaddr,
						     (size_t)uio_res->maps[i].size);

			/* unmap addrs correctly mapped */
			while (--i >= 0)
				vmbus_unmap_resource(uio_res->maps[i].addr,
						     (size_t)uio_res->maps[i].size);

			close(fd);
			return -1;
		}

		/* fd is not needed in slave process, close it */
		close(fd);

		dev->primary = uio_res->primary;
		if (!dev->primary) {
			VMBUS_LOG(ERR, "missing primary channel");
			return -1;
		}

		STAILQ_FOREACH(chan, &dev->primary->subchannel_list, next) {
			if (vmbus_uio_map_secondary_subchan(dev, chan) != 0) {
				VMBUS_LOG(ERR, "cannot map secondary subchan");
				return -1;
			}
		}

		return 0;
	}

	VMBUS_LOG(ERR,  "Cannot find resource for device");
	return 1;
}

static int
vmbus_uio_map_primary(struct rte_vmbus_device *dev)
{
	int i, ret;
	struct mapped_vmbus_resource *uio_res = NULL;
	struct mapped_vmbus_res_list *uio_res_list =
		RTE_TAILQ_CAST(vmbus_tailq.head, mapped_vmbus_res_list);

	/* allocate uio resource */
	ret = vmbus_uio_alloc_resource(dev, &uio_res);
	if (ret)
		return ret;

	/* Map the resources */
	for (i = 0; i < VMBUS_MAX_RESOURCE; i++) {
		/* stop at empty BAR */
		if (dev->resource[i].len == 0)
			break;

		ret = vmbus_uio_map_resource_by_index(dev, i, uio_res, 0);
		if (ret)
			goto error;
	}

	uio_res->nb_maps = i;

	TAILQ_INSERT_TAIL(uio_res_list, uio_res, next);

	return 0;
error:
	while (--i >= 0) {
		vmbus_unmap_resource(uio_res->maps[i].addr,
				(size_t)uio_res->maps[i].size);
	}
	vmbus_uio_free_resource(dev, uio_res);
	return -1;
}


struct mapped_vmbus_resource *
vmbus_uio_find_resource(const struct rte_vmbus_device *dev)
{
	struct mapped_vmbus_resource *uio_res;
	struct mapped_vmbus_res_list *uio_res_list =
			RTE_TAILQ_CAST(vmbus_tailq.head, mapped_vmbus_res_list);

	if (dev == NULL)
		return NULL;

	TAILQ_FOREACH(uio_res, uio_res_list, next) {
		/* skip this element if it doesn't match our VMBUS address */
		if (rte_uuid_compare(uio_res->id, dev->device_id) == 0)
			return uio_res;
	}
	return NULL;
}

/* map the VMBUS resource of a VMBUS device in virtual memory */
int
vmbus_uio_map_resource(struct rte_vmbus_device *dev)
{
	struct mapped_vmbus_resource *uio_res;
	int ret;

	/* TODO: handle rescind */
	dev->intr_handle.fd = -1;
	dev->intr_handle.uio_cfg_fd = -1;
	dev->intr_handle.type = RTE_INTR_HANDLE_UNKNOWN;

	/* secondary processes - use already recorded details */
	if (rte_eal_process_type() != RTE_PROC_PRIMARY)
		ret = vmbus_uio_map_secondary(dev);
	else
		ret = vmbus_uio_map_primary(dev);

	if (ret != 0)
		return ret;

	uio_res = vmbus_uio_find_resource(dev);
	if (!uio_res) {
		VMBUS_LOG(ERR, "can not find resources!");
		return -EIO;
	}

	if (uio_res->nb_maps <= HV_MON_PAGE_MAP) {
		VMBUS_LOG(ERR, "VMBUS: only %u resources found!",
			uio_res->nb_maps);
		return -EINVAL;
	}

	dev->int_page = (uint32_t *)((char *)uio_res->maps[HV_INT_PAGE_MAP].addr
				     + (PAGE_SIZE >> 1));
	dev->monitor_page = uio_res->maps[HV_MON_PAGE_MAP].addr;
	return 0;
}

static void
vmbus_uio_unmap(struct mapped_vmbus_resource *uio_res)
{
	int i;

	if (uio_res == NULL)
		return;

	for (i = 0; i != uio_res->nb_maps; i++) {
		vmbus_unmap_resource(uio_res->maps[i].addr,
				     (size_t)uio_res->maps[i].size);
	}
}

/* unmap the VMBUS resource of a VMBUS device in virtual memory */
void
vmbus_uio_unmap_resource(struct rte_vmbus_device *dev)
{
	struct mapped_vmbus_resource *uio_res;
	struct mapped_vmbus_res_list *uio_res_list =
			RTE_TAILQ_CAST(vmbus_tailq.head, mapped_vmbus_res_list);

	if (dev == NULL)
		return;

	/* find an entry for the device */
	uio_res = vmbus_uio_find_resource(dev);
	if (uio_res == NULL)
		return;

	/* secondary processes - just free maps */
	if (rte_eal_process_type() != RTE_PROC_PRIMARY)
		return vmbus_uio_unmap(uio_res);

	TAILQ_REMOVE(uio_res_list, uio_res, next);

	/* unmap all resources */
	vmbus_uio_unmap(uio_res);

	/* free uio resource */
	rte_free(uio_res);

	/* close fd if in primary process */
	close(dev->intr_handle.fd);
	if (dev->intr_handle.uio_cfg_fd >= 0) {
		close(dev->intr_handle.uio_cfg_fd);
		dev->intr_handle.uio_cfg_fd = -1;
	}

	dev->intr_handle.fd = -1;
	dev->intr_handle.type = RTE_INTR_HANDLE_UNKNOWN;
}