/*   SPDX-License-Identifier: BSD-3-Clause
 *   Copyright (c) Intel Corporation.
 *   All rights reserved.
 */

#include "spdk/likely.h"
#include "spdk/stdinc.h"
#include "spdk/nvme.h"
#include "spdk/thread.h"
#include "spdk/bdev_module.h"
#include "spdk/string.h"
#include "spdk/ftl.h"
#include "spdk/crc32.h"

#include "ftl_core.h"
#include "ftl_band.h"
#include "ftl_io.h"
#include "ftl_debug.h"
#include "ftl_internal.h"
#include "mngt/ftl_mngt.h"


size_t
spdk_ftl_io_size(void)
{
	return sizeof(struct ftl_io);
}

static void
ftl_io_cmpl_cb(struct spdk_bdev_io *bdev_io, bool success, void *cb_arg)
{
	struct ftl_io *io = cb_arg;

	if (spdk_unlikely(!success)) {
		io->status = -EIO;
	}

	ftl_io_dec_req(io);
	if (ftl_io_done(io)) {
		ftl_io_complete(io);
	}

	spdk_bdev_free_io(bdev_io);
}

static void
ftl_band_erase(struct ftl_band *band)
{
	assert(band->md->state == FTL_BAND_STATE_CLOSED ||
	       band->md->state == FTL_BAND_STATE_FREE);

	ftl_band_set_state(band, FTL_BAND_STATE_PREP);
}

static size_t
ftl_get_limit(const struct spdk_ftl_dev *dev, int type)
{
	assert(type < SPDK_FTL_LIMIT_MAX);
	return dev->conf.limits[type];
}

static bool
ftl_shutdown_complete(struct spdk_ftl_dev *dev)
{
	uint64_t i;

	if (dev->num_inflight) {
		return false;
	}

	if (!ftl_nv_cache_is_halted(&dev->nv_cache)) {
		ftl_nv_cache_halt(&dev->nv_cache);
		return false;
	}

	if (!ftl_writer_is_halted(&dev->writer_user)) {
		ftl_writer_halt(&dev->writer_user);
		return false;
	}

	if (!ftl_writer_is_halted(&dev->writer_gc)) {
		ftl_writer_halt(&dev->writer_gc);
		return false;
	}

	if (!ftl_nv_cache_chunks_busy(&dev->nv_cache)) {
		return false;
	}

	for (i = 0; i < ftl_get_num_bands(dev); ++i) {
		if (dev->bands[i].queue_depth ||
		    dev->bands[i].md->state == FTL_BAND_STATE_CLOSING) {
			return false;
		}
	}

	if (!ftl_l2p_is_halted(dev)) {
		ftl_l2p_halt(dev);
		return false;
	}

	return true;
}

void
ftl_apply_limits(struct spdk_ftl_dev *dev)
{
	size_t limit;
	int i;

	/*  Clear existing limit */
	dev->limit = SPDK_FTL_LIMIT_MAX;

	for (i = SPDK_FTL_LIMIT_CRIT; i < SPDK_FTL_LIMIT_MAX; ++i) {
		limit = ftl_get_limit(dev, i);

		if (dev->num_free <= limit) {
			dev->limit = i;
			break;
		}
	}
}

void
ftl_invalidate_addr(struct spdk_ftl_dev *dev, ftl_addr addr)
{
	struct ftl_band *band;
	struct ftl_p2l_map *p2l_map;

	if (ftl_addr_in_nvc(dev, addr)) {
		return;
	}

	band = ftl_band_from_addr(dev, addr);
	p2l_map = &band->p2l_map;

	/* TODO: fix case when the same address is invalidated from multiple sources */
	assert(p2l_map->num_valid > 0);
	p2l_map->num_valid--;

	/* Invalidate open/full band p2l_map entry to keep p2l and l2p
	 * consistency when band is going to close state */
	if (FTL_BAND_STATE_OPEN == band->md->state || FTL_BAND_STATE_FULL == band->md->state) {
		p2l_map->band_map[ftl_band_block_offset_from_addr(band, addr)] = FTL_LBA_INVALID;
	}
}

static int
ftl_read_canceled(int rc)
{
	return rc == -EFAULT;
}

static int
ftl_get_next_read_addr(struct ftl_io *io, ftl_addr *addr)
{
	struct spdk_ftl_dev *dev = io->dev;
	ftl_addr next_addr;
	size_t i;
	bool addr_cached = false;

	*addr = ftl_l2p_get(dev, ftl_io_current_lba(io));
	io->map[io->pos] = *addr;

	/* If the address is invalid, skip it */
	if (*addr == FTL_ADDR_INVALID) {
		return -EFAULT;
	}

	addr_cached = ftl_addr_in_nvc(dev, *addr);

	for (i = 1; i < ftl_io_iovec_len_left(io); ++i) {
		next_addr = ftl_l2p_get(dev, ftl_io_get_lba(io, io->pos + i));

		if (next_addr == FTL_ADDR_INVALID) {
			break;
		}

		/* It's not enough to check for contiguity, if user data is on the last block
		 * of base device and first nvc, then they're 'contiguous', but can't be handled
		 * with one read request.
		 */
		if (addr_cached != ftl_addr_in_nvc(dev, next_addr)) {
			break;
		}

		if (*addr + i != next_addr) {
			break;
		}

		io->map[io->pos + i] = next_addr;
	}

	return i;
}

static void ftl_submit_read(struct ftl_io *io);

static void
_ftl_submit_read(void *_io)
{
	struct ftl_io *io = _io;

	ftl_submit_read(io);
}

static void
ftl_submit_read(struct ftl_io *io)
{
	struct spdk_ftl_dev *dev = io->dev;
	ftl_addr addr;
	int rc = 0, num_blocks;

	while (io->pos < io->num_blocks) {
		num_blocks = ftl_get_next_read_addr(io, &addr);
		rc = num_blocks;

		/* User LBA doesn't hold valid data (trimmed or never written to), fill with 0 and skip this block */
		if (ftl_read_canceled(rc)) {
			memset(ftl_io_iovec_addr(io), 0, FTL_BLOCK_SIZE);
			ftl_io_advance(io, 1);
			continue;
		}

		assert(num_blocks > 0);

		if (ftl_addr_in_nvc(dev, addr)) {
			rc = ftl_nv_cache_read(io, addr, num_blocks, ftl_io_cmpl_cb, io);
		} else {
			rc = spdk_bdev_read_blocks(dev->base_bdev_desc, dev->base_ioch,
						   ftl_io_iovec_addr(io),
						   addr, num_blocks, ftl_io_cmpl_cb, io);
		}

		if (spdk_unlikely(rc)) {
			if (rc == -ENOMEM) {
				struct spdk_bdev *bdev;
				struct spdk_io_channel *ch;

				if (ftl_addr_in_nvc(dev, addr)) {
					bdev = spdk_bdev_desc_get_bdev(dev->nv_cache.bdev_desc);
					ch = dev->nv_cache.cache_ioch;
				} else {
					bdev = spdk_bdev_desc_get_bdev(dev->base_bdev_desc);
					ch = dev->base_ioch;
				}
				io->bdev_io_wait.bdev = bdev;
				io->bdev_io_wait.cb_fn = _ftl_submit_read;
				io->bdev_io_wait.cb_arg = io;
				spdk_bdev_queue_io_wait(bdev, ch, &io->bdev_io_wait);
				return;
			} else {
				ftl_abort();
			}
		}

		ftl_io_inc_req(io);
		ftl_io_advance(io, num_blocks);
	}

	/* If we didn't have to read anything from the device, */
	/* complete the request right away */
	if (ftl_io_done(io)) {
		ftl_io_complete(io);
	}
}

void
spdk_ftl_dev_get_attrs(const struct spdk_ftl_dev *dev, struct spdk_ftl_attrs *attrs)
{
	attrs->num_blocks = dev->num_lbas;
	attrs->block_size = FTL_BLOCK_SIZE;
	attrs->optimum_io_size = dev->xfer_size;
}

static void
ftl_io_pin_cb(struct spdk_ftl_dev *dev, int status, struct ftl_l2p_pin_ctx *pin_ctx)
{
	struct ftl_io *io = pin_ctx->cb_ctx;

	if (spdk_unlikely(status != 0)) {
		/* Retry on the internal L2P fault */
		io->status = -EAGAIN;
		ftl_io_complete(io);
		return;
	}

	io->flags |= FTL_IO_PINNED;
	ftl_submit_read(io);
}

static void
ftl_io_pin(struct ftl_io *io)
{
	if (spdk_unlikely(io->flags & FTL_IO_PINNED)) {
		/*
		 * The IO is in a retry path and it had been pinned already.
		 * Continue with further processing.
		 */
		ftl_l2p_pin_skip(io->dev, ftl_io_pin_cb, io, &io->l2p_pin_ctx);
	} else {
		/* First time when pinning the IO */
		ftl_l2p_pin(io->dev, io->lba, io->num_blocks,
			    ftl_io_pin_cb, io, &io->l2p_pin_ctx);
	}
}

static void
start_io(struct ftl_io *io)
{
	struct ftl_io_channel *ioch = ftl_io_channel_get_ctx(io->ioch);
	struct spdk_ftl_dev *dev = io->dev;

	io->map = ftl_mempool_get(ioch->map_pool);
	if (spdk_unlikely(!io->map)) {
		io->status = -ENOMEM;
		ftl_io_complete(io);
		return;
	}

	switch (io->type) {
	case FTL_IO_READ:
		TAILQ_INSERT_TAIL(&dev->rd_sq, io, queue_entry);
		break;
	case FTL_IO_WRITE:
		TAILQ_INSERT_TAIL(&dev->wr_sq, io, queue_entry);
		break;
	case FTL_IO_UNMAP:
	default:
		io->status = -EOPNOTSUPP;
		ftl_io_complete(io);
	}
}

static int
queue_io(struct spdk_ftl_dev *dev, struct ftl_io *io)
{
	size_t result;
	struct ftl_io_channel *ioch = ftl_io_channel_get_ctx(io->ioch);

	result = spdk_ring_enqueue(ioch->sq, (void **)&io, 1, NULL);
	if (spdk_unlikely(0 == result)) {
		return -EAGAIN;
	}

	return 0;
}

int
spdk_ftl_writev(struct spdk_ftl_dev *dev, struct ftl_io *io, struct spdk_io_channel *ch,
		uint64_t lba, uint64_t lba_cnt, struct iovec *iov, size_t iov_cnt, spdk_ftl_fn cb_fn,
		void *cb_arg)
{
	int rc;

	if (iov_cnt == 0) {
		return -EINVAL;
	}

	if (lba_cnt == 0) {
		return -EINVAL;
	}

	if (lba_cnt != ftl_iovec_num_blocks(iov, iov_cnt)) {
		FTL_ERRLOG(dev, "Invalid IO vector to handle, device %s, LBA %"PRIu64"\n",
			   dev->conf.name, lba);
		return -EINVAL;
	}

	if (!dev->initialized) {
		return -EBUSY;
	}

	rc = ftl_io_init(ch, io, lba, lba_cnt, iov, iov_cnt, cb_fn, cb_arg, FTL_IO_WRITE);
	if (rc) {
		return rc;
	}

	return queue_io(dev, io);
}

int
spdk_ftl_readv(struct spdk_ftl_dev *dev, struct ftl_io *io, struct spdk_io_channel *ch,
	       uint64_t lba, uint64_t lba_cnt, struct iovec *iov, size_t iov_cnt, spdk_ftl_fn cb_fn, void *cb_arg)
{
	int rc;

	if (iov_cnt == 0) {
		return -EINVAL;
	}

	if (lba_cnt == 0) {
		return -EINVAL;
	}

	if (lba_cnt != ftl_iovec_num_blocks(iov, iov_cnt)) {
		FTL_ERRLOG(dev, "Invalid IO vector to handle, device %s, LBA %"PRIu64"\n",
			   dev->conf.name, lba);
		return -EINVAL;
	}

	if (!dev->initialized) {
		return -EBUSY;
	}

	rc = ftl_io_init(ch, io, lba, lba_cnt, iov, iov_cnt, cb_fn, cb_arg, FTL_IO_READ);
	if (rc) {
		return rc;
	}

	return queue_io(dev, io);
}

#define FTL_IO_QUEUE_BATCH 16
int
ftl_io_channel_poll(void *arg)
{
	struct ftl_io_channel *ch = arg;
	void *ios[FTL_IO_QUEUE_BATCH];
	uint64_t i, count;

	count = spdk_ring_dequeue(ch->cq, ios, FTL_IO_QUEUE_BATCH);
	if (count == 0) {
		return SPDK_POLLER_IDLE;
	}

	for (i = 0; i < count; i++) {
		struct ftl_io *io = ios[i];
		io->user_fn(io->cb_ctx, io->status);
	}

	return SPDK_POLLER_BUSY;
}

static void
ftl_process_io_channel(struct spdk_ftl_dev *dev, struct ftl_io_channel *ioch)
{
	void *ios[FTL_IO_QUEUE_BATCH];
	size_t count, i;

	count = spdk_ring_dequeue(ioch->sq, ios, FTL_IO_QUEUE_BATCH);
	if (count == 0) {
		return;
	}

	for (i = 0; i < count; i++) {
		struct ftl_io *io = ios[i];
		start_io(io);
	}
}

static void
ftl_process_io_queue(struct spdk_ftl_dev *dev)
{
	struct ftl_io_channel *ioch;
	struct ftl_io *io;

	/* TODO: Try to figure out a mechanism to batch more requests at the same time,
	 * with keeping enough resources (pinned pages), between reads, writes and gc/compaction
	 */
	if (!TAILQ_EMPTY(&dev->rd_sq)) {
		io = TAILQ_FIRST(&dev->rd_sq);
		TAILQ_REMOVE(&dev->rd_sq, io, queue_entry);
		assert(io->type == FTL_IO_READ);
		ftl_io_pin(io);
	}

	if (!ftl_nv_cache_full(&dev->nv_cache) && !TAILQ_EMPTY(&dev->wr_sq)) {
		io = TAILQ_FIRST(&dev->wr_sq);
		TAILQ_REMOVE(&dev->wr_sq, io, queue_entry);
		assert(io->type == FTL_IO_WRITE);
		if (!ftl_nv_cache_write(io)) {
			TAILQ_INSERT_HEAD(&dev->wr_sq, io, queue_entry);
		}
	}

	TAILQ_FOREACH(ioch, &dev->ioch_queue, entry) {
		ftl_process_io_channel(dev, ioch);
	}
}

int
ftl_core_poller(void *ctx)
{
	struct spdk_ftl_dev *dev = ctx;
	uint64_t io_activity_total_old = dev->io_activity_total;

	if (dev->halt && ftl_shutdown_complete(dev)) {
		spdk_poller_unregister(&dev->core_poller);
		return SPDK_POLLER_IDLE;
	}

	ftl_process_io_queue(dev);
	ftl_writer_run(&dev->writer_user);
	ftl_writer_run(&dev->writer_gc);
	ftl_nv_cache_process(dev);
	ftl_l2p_process(dev);

	if (io_activity_total_old != dev->io_activity_total) {
		return SPDK_POLLER_BUSY;
	}

	return SPDK_POLLER_IDLE;
}

struct ftl_band *
ftl_band_get_next_free(struct spdk_ftl_dev *dev)
{
	struct ftl_band *band = NULL;

	if (!TAILQ_EMPTY(&dev->free_bands)) {
		band = TAILQ_FIRST(&dev->free_bands);
		TAILQ_REMOVE(&dev->free_bands, band, queue_entry);
		ftl_band_erase(band);
	}

	return band;
}

void *g_ftl_write_buf;
void *g_ftl_read_buf;

int
spdk_ftl_init(void)
{
	g_ftl_write_buf = spdk_zmalloc(FTL_ZERO_BUFFER_SIZE, FTL_ZERO_BUFFER_SIZE, NULL,
				       SPDK_ENV_LCORE_ID_ANY, SPDK_MALLOC_DMA);
	if (!g_ftl_write_buf) {
		return -ENOMEM;
	}

	g_ftl_read_buf = spdk_zmalloc(FTL_ZERO_BUFFER_SIZE, FTL_ZERO_BUFFER_SIZE, NULL,
				      SPDK_ENV_LCORE_ID_ANY, SPDK_MALLOC_DMA);
	if (!g_ftl_read_buf) {
		spdk_free(g_ftl_write_buf);
		g_ftl_write_buf = NULL;
		return -ENOMEM;
	}
	return 0;
}

void
spdk_ftl_fini(void)
{
	spdk_free(g_ftl_write_buf);
	spdk_free(g_ftl_read_buf);
}

struct spdk_io_channel *
spdk_ftl_get_io_channel(struct spdk_ftl_dev *dev)
{
	return spdk_get_io_channel(dev);
}

SPDK_LOG_REGISTER_COMPONENT(ftl_core)