/*
 * Copyright (C) 2015 IT University of Copenhagen. All rights reserved.
 * Initial release: Matias Bjorling <m@bjorling.me>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version
 * 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
 * USA.
 *
 */

#include <linux/list.h>
#include <linux/types.h>
#include <linux/sem.h>
#include <linux/bitmap.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/miscdevice.h>
#include <linux/lightnvm.h>
#include <linux/sched/sysctl.h>

static LIST_HEAD(nvm_tgt_types);
static DECLARE_RWSEM(nvm_tgtt_lock);
static LIST_HEAD(nvm_devices);
static DECLARE_RWSEM(nvm_lock);

/* Map between virtual and physical channel and lun */
struct nvm_ch_map {
	int ch_off;
	int num_lun;
	int *lun_offs;
};

struct nvm_dev_map {
	struct nvm_ch_map *chnls;
	int num_ch;
};

static struct nvm_target *nvm_find_target(struct nvm_dev *dev, const char *name)
{
	struct nvm_target *tgt;

	list_for_each_entry(tgt, &dev->targets, list)
		if (!strcmp(name, tgt->disk->disk_name))
			return tgt;

	return NULL;
}

static bool nvm_target_exists(const char *name)
{
	struct nvm_dev *dev;
	struct nvm_target *tgt;
	bool ret = false;

	down_write(&nvm_lock);
	list_for_each_entry(dev, &nvm_devices, devices) {
		mutex_lock(&dev->mlock);
		list_for_each_entry(tgt, &dev->targets, list) {
			if (!strcmp(name, tgt->disk->disk_name)) {
				ret = true;
				mutex_unlock(&dev->mlock);
				goto out;
			}
		}
		mutex_unlock(&dev->mlock);
	}

out:
	up_write(&nvm_lock);
	return ret;
}

static int nvm_reserve_luns(struct nvm_dev *dev, int lun_begin, int lun_end)
{
	int i;

	for (i = lun_begin; i <= lun_end; i++) {
		if (test_and_set_bit(i, dev->lun_map)) {
			pr_err("nvm: lun %d already allocated\n", i);
			goto err;
		}
	}

	return 0;
err:
	while (--i >= lun_begin)
		clear_bit(i, dev->lun_map);

	return -EBUSY;
}

static void nvm_release_luns_err(struct nvm_dev *dev, int lun_begin,
				 int lun_end)
{
	int i;

	for (i = lun_begin; i <= lun_end; i++)
		WARN_ON(!test_and_clear_bit(i, dev->lun_map));
}

static void nvm_remove_tgt_dev(struct nvm_tgt_dev *tgt_dev, int clear)
{
	struct nvm_dev *dev = tgt_dev->parent;
	struct nvm_dev_map *dev_map = tgt_dev->map;
	int i, j;

	for (i = 0; i < dev_map->num_ch; i++) {
		struct nvm_ch_map *ch_map = &dev_map->chnls[i];
		int *lun_offs = ch_map->lun_offs;
		int ch = i + ch_map->ch_off;

		if (clear) {
			for (j = 0; j < ch_map->num_lun; j++) {
				int lun = j + lun_offs[j];
				int lunid = (ch * dev->geo.num_lun) + lun;

				WARN_ON(!test_and_clear_bit(lunid,
							dev->lun_map));
			}
		}

		kfree(ch_map->lun_offs);
	}

	kfree(dev_map->chnls);
	kfree(dev_map);

	kfree(tgt_dev->luns);
	kfree(tgt_dev);
}

static struct nvm_tgt_dev *nvm_create_tgt_dev(struct nvm_dev *dev,
					      u16 lun_begin, u16 lun_end,
					      u16 op)
{
	struct nvm_tgt_dev *tgt_dev = NULL;
	struct nvm_dev_map *dev_rmap = dev->rmap;
	struct nvm_dev_map *dev_map;
	struct ppa_addr *luns;
	int num_lun = lun_end - lun_begin + 1;
	int luns_left = num_lun;
	int num_ch = num_lun / dev->geo.num_lun;
	int num_ch_mod = num_lun % dev->geo.num_lun;
	int bch = lun_begin / dev->geo.num_lun;
	int blun = lun_begin % dev->geo.num_lun;
	int lunid = 0;
	int lun_balanced = 1;
	int sec_per_lun, prev_num_lun;
	int i, j;

	num_ch = (num_ch_mod == 0) ? num_ch : num_ch + 1;

	dev_map = kmalloc(sizeof(struct nvm_dev_map), GFP_KERNEL);
	if (!dev_map)
		goto err_dev;

	dev_map->chnls = kcalloc(num_ch, sizeof(struct nvm_ch_map), GFP_KERNEL);
	if (!dev_map->chnls)
		goto err_chnls;

	luns = kcalloc(num_lun, sizeof(struct ppa_addr), GFP_KERNEL);
	if (!luns)
		goto err_luns;

	prev_num_lun = (luns_left > dev->geo.num_lun) ?
					dev->geo.num_lun : luns_left;
	for (i = 0; i < num_ch; i++) {
		struct nvm_ch_map *ch_rmap = &dev_rmap->chnls[i + bch];
		int *lun_roffs = ch_rmap->lun_offs;
		struct nvm_ch_map *ch_map = &dev_map->chnls[i];
		int *lun_offs;
		int luns_in_chnl = (luns_left > dev->geo.num_lun) ?
					dev->geo.num_lun : luns_left;

		if (lun_balanced && prev_num_lun != luns_in_chnl)
			lun_balanced = 0;

		ch_map->ch_off = ch_rmap->ch_off = bch;
		ch_map->num_lun = luns_in_chnl;

		lun_offs = kcalloc(luns_in_chnl, sizeof(int), GFP_KERNEL);
		if (!lun_offs)
			goto err_ch;

		for (j = 0; j < luns_in_chnl; j++) {
			luns[lunid].ppa = 0;
			luns[lunid].a.ch = i;
			luns[lunid++].a.lun = j;

			lun_offs[j] = blun;
			lun_roffs[j + blun] = blun;
		}

		ch_map->lun_offs = lun_offs;

		/* when starting a new channel, lun offset is reset */
		blun = 0;
		luns_left -= luns_in_chnl;
	}

	dev_map->num_ch = num_ch;

	tgt_dev = kmalloc(sizeof(struct nvm_tgt_dev), GFP_KERNEL);
	if (!tgt_dev)
		goto err_ch;

	/* Inherit device geometry from parent */
	memcpy(&tgt_dev->geo, &dev->geo, sizeof(struct nvm_geo));

	/* Target device only owns a portion of the physical device */
	tgt_dev->geo.num_ch = num_ch;
	tgt_dev->geo.num_lun = (lun_balanced) ? prev_num_lun : -1;
	tgt_dev->geo.all_luns = num_lun;
	tgt_dev->geo.all_chunks = num_lun * dev->geo.num_chk;

	tgt_dev->geo.op = op;

	sec_per_lun = dev->geo.clba * dev->geo.num_chk;
	tgt_dev->geo.total_secs = num_lun * sec_per_lun;

	tgt_dev->q = dev->q;
	tgt_dev->map = dev_map;
	tgt_dev->luns = luns;
	tgt_dev->parent = dev;

	return tgt_dev;
err_ch:
	while (--i >= 0)
		kfree(dev_map->chnls[i].lun_offs);
	kfree(luns);
err_luns:
	kfree(dev_map->chnls);
err_chnls:
	kfree(dev_map);
err_dev:
	return tgt_dev;
}

static const struct block_device_operations nvm_fops = {
	.owner		= THIS_MODULE,
};

static struct nvm_tgt_type *__nvm_find_target_type(const char *name)
{
	struct nvm_tgt_type *tt;

	list_for_each_entry(tt, &nvm_tgt_types, list)
		if (!strcmp(name, tt->name))
			return tt;

	return NULL;
}

static struct nvm_tgt_type *nvm_find_target_type(const char *name)
{
	struct nvm_tgt_type *tt;

	down_write(&nvm_tgtt_lock);
	tt = __nvm_find_target_type(name);
	up_write(&nvm_tgtt_lock);

	return tt;
}

static int nvm_config_check_luns(struct nvm_geo *geo, int lun_begin,
				 int lun_end)
{
	if (lun_begin > lun_end || lun_end >= geo->all_luns) {
		pr_err("nvm: lun out of bound (%u:%u > %u)\n",
			lun_begin, lun_end, geo->all_luns - 1);
		return -EINVAL;
	}

	return 0;
}

static int __nvm_config_simple(struct nvm_dev *dev,
			       struct nvm_ioctl_create_simple *s)
{
	struct nvm_geo *geo = &dev->geo;

	if (s->lun_begin == -1 && s->lun_end == -1) {
		s->lun_begin = 0;
		s->lun_end = geo->all_luns - 1;
	}

	return nvm_config_check_luns(geo, s->lun_begin, s->lun_end);
}

static int __nvm_config_extended(struct nvm_dev *dev,
				 struct nvm_ioctl_create_extended *e)
{
	if (e->lun_begin == 0xFFFF && e->lun_end == 0xFFFF) {
		e->lun_begin = 0;
		e->lun_end = dev->geo.all_luns - 1;
	}

	/* op not set falls into target's default */
	if (e->op == 0xFFFF) {
		e->op = NVM_TARGET_DEFAULT_OP;
	} else if (e->op < NVM_TARGET_MIN_OP || e->op > NVM_TARGET_MAX_OP) {
		pr_err("nvm: invalid over provisioning value\n");
		return -EINVAL;
	}

	return nvm_config_check_luns(&dev->geo, e->lun_begin, e->lun_end);
}

static int nvm_create_tgt(struct nvm_dev *dev, struct nvm_ioctl_create *create)
{
	struct nvm_ioctl_create_extended e;
	struct request_queue *tqueue;
	struct gendisk *tdisk;
	struct nvm_tgt_type *tt;
	struct nvm_target *t;
	struct nvm_tgt_dev *tgt_dev;
	void *targetdata;
	int ret;

	switch (create->conf.type) {
	case NVM_CONFIG_TYPE_SIMPLE:
		ret = __nvm_config_simple(dev, &create->conf.s);
		if (ret)
			return ret;

		e.lun_begin = create->conf.s.lun_begin;
		e.lun_end = create->conf.s.lun_end;
		e.op = NVM_TARGET_DEFAULT_OP;
		break;
	case NVM_CONFIG_TYPE_EXTENDED:
		ret = __nvm_config_extended(dev, &create->conf.e);
		if (ret)
			return ret;

		e = create->conf.e;
		break;
	default:
		pr_err("nvm: config type not valid\n");
		return -EINVAL;
	}

	tt = nvm_find_target_type(create->tgttype);
	if (!tt) {
		pr_err("nvm: target type %s not found\n", create->tgttype);
		return -EINVAL;
	}

	if ((tt->flags & NVM_TGT_F_HOST_L2P) != (dev->geo.dom & NVM_RSP_L2P)) {
		pr_err("nvm: device is incompatible with target L2P type.\n");
		return -EINVAL;
	}

	if (nvm_target_exists(create->tgtname)) {
		pr_err("nvm: target name already exists (%s)\n",
							create->tgtname);
		return -EINVAL;
	}

	ret = nvm_reserve_luns(dev, e.lun_begin, e.lun_end);
	if (ret)
		return ret;

	t = kmalloc(sizeof(struct nvm_target), GFP_KERNEL);
	if (!t) {
		ret = -ENOMEM;
		goto err_reserve;
	}

	tgt_dev = nvm_create_tgt_dev(dev, e.lun_begin, e.lun_end, e.op);
	if (!tgt_dev) {
		pr_err("nvm: could not create target device\n");
		ret = -ENOMEM;
		goto err_t;
	}

	tdisk = alloc_disk(0);
	if (!tdisk) {
		ret = -ENOMEM;
		goto err_dev;
	}

	tqueue = blk_alloc_queue_node(GFP_KERNEL, dev->q->node, NULL);
	if (!tqueue) {
		ret = -ENOMEM;
		goto err_disk;
	}
	blk_queue_make_request(tqueue, tt->make_rq);

	strlcpy(tdisk->disk_name, create->tgtname, sizeof(tdisk->disk_name));
	tdisk->flags = GENHD_FL_EXT_DEVT;
	tdisk->major = 0;
	tdisk->first_minor = 0;
	tdisk->fops = &nvm_fops;
	tdisk->queue = tqueue;

	targetdata = tt->init(tgt_dev, tdisk, create->flags);
	if (IS_ERR(targetdata)) {
		ret = PTR_ERR(targetdata);
		goto err_init;
	}

	tdisk->private_data = targetdata;
	tqueue->queuedata = targetdata;

	blk_queue_max_hw_sectors(tqueue,
			(dev->geo.csecs >> 9) * NVM_MAX_VLBA);

	set_capacity(tdisk, tt->capacity(targetdata));
	add_disk(tdisk);

	if (tt->sysfs_init && tt->sysfs_init(tdisk)) {
		ret = -ENOMEM;
		goto err_sysfs;
	}

	t->type = tt;
	t->disk = tdisk;
	t->dev = tgt_dev;

	mutex_lock(&dev->mlock);
	list_add_tail(&t->list, &dev->targets);
	mutex_unlock(&dev->mlock);

	__module_get(tt->owner);

	return 0;
err_sysfs:
	if (tt->exit)
		tt->exit(targetdata, true);
err_init:
	blk_cleanup_queue(tqueue);
	tdisk->queue = NULL;
err_disk:
	put_disk(tdisk);
err_dev:
	nvm_remove_tgt_dev(tgt_dev, 0);
err_t:
	kfree(t);
err_reserve:
	nvm_release_luns_err(dev, e.lun_begin, e.lun_end);
	return ret;
}

static void __nvm_remove_target(struct nvm_target *t, bool graceful)
{
	struct nvm_tgt_type *tt = t->type;
	struct gendisk *tdisk = t->disk;
	struct request_queue *q = tdisk->queue;

	del_gendisk(tdisk);
	blk_cleanup_queue(q);

	if (tt->sysfs_exit)
		tt->sysfs_exit(tdisk);

	if (tt->exit)
		tt->exit(tdisk->private_data, graceful);

	nvm_remove_tgt_dev(t->dev, 1);
	put_disk(tdisk);
	module_put(t->type->owner);

	list_del(&t->list);
	kfree(t);
}

/**
 * nvm_remove_tgt - Removes a target from the media manager
 * @dev:	device
 * @remove:	ioctl structure with target name to remove.
 *
 * Returns:
 * 0: on success
 * 1: on not found
 * <0: on error
 */
static int nvm_remove_tgt(struct nvm_dev *dev, struct nvm_ioctl_remove *remove)
{
	struct nvm_target *t;

	mutex_lock(&dev->mlock);
	t = nvm_find_target(dev, remove->tgtname);
	if (!t) {
		mutex_unlock(&dev->mlock);
		return 1;
	}
	__nvm_remove_target(t, true);
	mutex_unlock(&dev->mlock);

	return 0;
}

static int nvm_register_map(struct nvm_dev *dev)
{
	struct nvm_dev_map *rmap;
	int i, j;

	rmap = kmalloc(sizeof(struct nvm_dev_map), GFP_KERNEL);
	if (!rmap)
		goto err_rmap;

	rmap->chnls = kcalloc(dev->geo.num_ch, sizeof(struct nvm_ch_map),
								GFP_KERNEL);
	if (!rmap->chnls)
		goto err_chnls;

	for (i = 0; i < dev->geo.num_ch; i++) {
		struct nvm_ch_map *ch_rmap;
		int *lun_roffs;
		int luns_in_chnl = dev->geo.num_lun;

		ch_rmap = &rmap->chnls[i];

		ch_rmap->ch_off = -1;
		ch_rmap->num_lun = luns_in_chnl;

		lun_roffs = kcalloc(luns_in_chnl, sizeof(int), GFP_KERNEL);
		if (!lun_roffs)
			goto err_ch;

		for (j = 0; j < luns_in_chnl; j++)
			lun_roffs[j] = -1;

		ch_rmap->lun_offs = lun_roffs;
	}

	dev->rmap = rmap;

	return 0;
err_ch:
	while (--i >= 0)
		kfree(rmap->chnls[i].lun_offs);
err_chnls:
	kfree(rmap);
err_rmap:
	return -ENOMEM;
}

static void nvm_unregister_map(struct nvm_dev *dev)
{
	struct nvm_dev_map *rmap = dev->rmap;
	int i;

	for (i = 0; i < dev->geo.num_ch; i++)
		kfree(rmap->chnls[i].lun_offs);

	kfree(rmap->chnls);
	kfree(rmap);
}

static void nvm_map_to_dev(struct nvm_tgt_dev *tgt_dev, struct ppa_addr *p)
{
	struct nvm_dev_map *dev_map = tgt_dev->map;
	struct nvm_ch_map *ch_map = &dev_map->chnls[p->a.ch];
	int lun_off = ch_map->lun_offs[p->a.lun];

	p->a.ch += ch_map->ch_off;
	p->a.lun += lun_off;
}

static void nvm_map_to_tgt(struct nvm_tgt_dev *tgt_dev, struct ppa_addr *p)
{
	struct nvm_dev *dev = tgt_dev->parent;
	struct nvm_dev_map *dev_rmap = dev->rmap;
	struct nvm_ch_map *ch_rmap = &dev_rmap->chnls[p->a.ch];
	int lun_roff = ch_rmap->lun_offs[p->a.lun];

	p->a.ch -= ch_rmap->ch_off;
	p->a.lun -= lun_roff;
}

static void nvm_ppa_tgt_to_dev(struct nvm_tgt_dev *tgt_dev,
				struct ppa_addr *ppa_list, int nr_ppas)
{
	int i;

	for (i = 0; i < nr_ppas; i++) {
		nvm_map_to_dev(tgt_dev, &ppa_list[i]);
		ppa_list[i] = generic_to_dev_addr(tgt_dev->parent, ppa_list[i]);
	}
}

static void nvm_ppa_dev_to_tgt(struct nvm_tgt_dev *tgt_dev,
				struct ppa_addr *ppa_list, int nr_ppas)
{
	int i;

	for (i = 0; i < nr_ppas; i++) {
		ppa_list[i] = dev_to_generic_addr(tgt_dev->parent, ppa_list[i]);
		nvm_map_to_tgt(tgt_dev, &ppa_list[i]);
	}
}

static void nvm_rq_tgt_to_dev(struct nvm_tgt_dev *tgt_dev, struct nvm_rq *rqd)
{
	struct ppa_addr *ppa_list = nvm_rq_to_ppa_list(rqd);

	nvm_ppa_tgt_to_dev(tgt_dev, ppa_list, rqd->nr_ppas);
}

static void nvm_rq_dev_to_tgt(struct nvm_tgt_dev *tgt_dev, struct nvm_rq *rqd)
{
	struct ppa_addr *ppa_list = nvm_rq_to_ppa_list(rqd);

	nvm_ppa_dev_to_tgt(tgt_dev, ppa_list, rqd->nr_ppas);
}

int nvm_register_tgt_type(struct nvm_tgt_type *tt)
{
	int ret = 0;

	down_write(&nvm_tgtt_lock);
	if (__nvm_find_target_type(tt->name))
		ret = -EEXIST;
	else
		list_add(&tt->list, &nvm_tgt_types);
	up_write(&nvm_tgtt_lock);

	return ret;
}
EXPORT_SYMBOL(nvm_register_tgt_type);

void nvm_unregister_tgt_type(struct nvm_tgt_type *tt)
{
	if (!tt)
		return;

	down_write(&nvm_tgtt_lock);
	list_del(&tt->list);
	up_write(&nvm_tgtt_lock);
}
EXPORT_SYMBOL(nvm_unregister_tgt_type);

void *nvm_dev_dma_alloc(struct nvm_dev *dev, gfp_t mem_flags,
							dma_addr_t *dma_handler)
{
	return dev->ops->dev_dma_alloc(dev, dev->dma_pool, mem_flags,
								dma_handler);
}
EXPORT_SYMBOL(nvm_dev_dma_alloc);

void nvm_dev_dma_free(struct nvm_dev *dev, void *addr, dma_addr_t dma_handler)
{
	dev->ops->dev_dma_free(dev->dma_pool, addr, dma_handler);
}
EXPORT_SYMBOL(nvm_dev_dma_free);

static struct nvm_dev *nvm_find_nvm_dev(const char *name)
{
	struct nvm_dev *dev;

	list_for_each_entry(dev, &nvm_devices, devices)
		if (!strcmp(name, dev->name))
			return dev;

	return NULL;
}

static int nvm_set_rqd_ppalist(struct nvm_tgt_dev *tgt_dev, struct nvm_rq *rqd,
			const struct ppa_addr *ppas, int nr_ppas)
{
	struct nvm_dev *dev = tgt_dev->parent;
	struct nvm_geo *geo = &tgt_dev->geo;
	int i, plane_cnt, pl_idx;
	struct ppa_addr ppa;

	if (geo->pln_mode == NVM_PLANE_SINGLE && nr_ppas == 1) {
		rqd->nr_ppas = nr_ppas;
		rqd->ppa_addr = ppas[0];

		return 0;
	}

	rqd->nr_ppas = nr_ppas;
	rqd->ppa_list = nvm_dev_dma_alloc(dev, GFP_KERNEL, &rqd->dma_ppa_list);
	if (!rqd->ppa_list) {
		pr_err("nvm: failed to allocate dma memory\n");
		return -ENOMEM;
	}

	plane_cnt = geo->pln_mode;
	rqd->nr_ppas *= plane_cnt;

	for (i = 0; i < nr_ppas; i++) {
		for (pl_idx = 0; pl_idx < plane_cnt; pl_idx++) {
			ppa = ppas[i];
			ppa.g.pl = pl_idx;
			rqd->ppa_list[(pl_idx * nr_ppas) + i] = ppa;
		}
	}

	return 0;
}

static void nvm_free_rqd_ppalist(struct nvm_tgt_dev *tgt_dev,
			struct nvm_rq *rqd)
{
	if (!rqd->ppa_list)
		return;

	nvm_dev_dma_free(tgt_dev->parent, rqd->ppa_list, rqd->dma_ppa_list);
}

static int nvm_set_flags(struct nvm_geo *geo, struct nvm_rq *rqd)
{
	int flags = 0;

	if (geo->version == NVM_OCSSD_SPEC_20)
		return 0;

	if (rqd->is_seq)
		flags |= geo->pln_mode >> 1;

	if (rqd->opcode == NVM_OP_PREAD)
		flags |= (NVM_IO_SCRAMBLE_ENABLE | NVM_IO_SUSPEND);
	else if (rqd->opcode == NVM_OP_PWRITE)
		flags |= NVM_IO_SCRAMBLE_ENABLE;

	return flags;
}

int nvm_submit_io(struct nvm_tgt_dev *tgt_dev, struct nvm_rq *rqd)
{
	struct nvm_dev *dev = tgt_dev->parent;
	int ret;

	if (!dev->ops->submit_io)
		return -ENODEV;

	nvm_rq_tgt_to_dev(tgt_dev, rqd);

	rqd->dev = tgt_dev;
	rqd->flags = nvm_set_flags(&tgt_dev->geo, rqd);

	/* In case of error, fail with right address format */
	ret = dev->ops->submit_io(dev, rqd);
	if (ret)
		nvm_rq_dev_to_tgt(tgt_dev, rqd);
	return ret;
}
EXPORT_SYMBOL(nvm_submit_io);

int nvm_submit_io_sync(struct nvm_tgt_dev *tgt_dev, struct nvm_rq *rqd)
{
	struct nvm_dev *dev = tgt_dev->parent;
	int ret;

	if (!dev->ops->submit_io_sync)
		return -ENODEV;

	nvm_rq_tgt_to_dev(tgt_dev, rqd);

	rqd->dev = tgt_dev;
	rqd->flags = nvm_set_flags(&tgt_dev->geo, rqd);

	/* In case of error, fail with right address format */
	ret = dev->ops->submit_io_sync(dev, rqd);
	nvm_rq_dev_to_tgt(tgt_dev, rqd);

	return ret;
}
EXPORT_SYMBOL(nvm_submit_io_sync);

void nvm_end_io(struct nvm_rq *rqd)
{
	struct nvm_tgt_dev *tgt_dev = rqd->dev;

	/* Convert address space */
	if (tgt_dev)
		nvm_rq_dev_to_tgt(tgt_dev, rqd);

	if (rqd->end_io)
		rqd->end_io(rqd);
}
EXPORT_SYMBOL(nvm_end_io);

static int nvm_submit_io_sync_raw(struct nvm_dev *dev, struct nvm_rq *rqd)
{
	if (!dev->ops->submit_io_sync)
		return -ENODEV;

	rqd->flags = nvm_set_flags(&dev->geo, rqd);

	return dev->ops->submit_io_sync(dev, rqd);
}

static int nvm_bb_chunk_sense(struct nvm_dev *dev, struct ppa_addr ppa)
{
	struct nvm_rq rqd = { NULL };
	struct bio bio;
	struct bio_vec bio_vec;
	struct page *page;
	int ret;

	page = alloc_page(GFP_KERNEL);
	if (!page)
		return -ENOMEM;

	bio_init(&bio, &bio_vec, 1);
	bio_add_page(&bio, page, PAGE_SIZE, 0);
	bio_set_op_attrs(&bio, REQ_OP_READ, 0);

	rqd.bio = &bio;
	rqd.opcode = NVM_OP_PREAD;
	rqd.is_seq = 1;
	rqd.nr_ppas = 1;
	rqd.ppa_addr = generic_to_dev_addr(dev, ppa);

	ret = nvm_submit_io_sync_raw(dev, &rqd);
	if (ret)
		return ret;

	__free_page(page);

	return rqd.error;
}

/*
 * Scans a 1.2 chunk first and last page to determine if its state.
 * If the chunk is found to be open, also scan it to update the write
 * pointer.
 */
static int nvm_bb_chunk_scan(struct nvm_dev *dev, struct ppa_addr ppa,
			     struct nvm_chk_meta *meta)
{
	struct nvm_geo *geo = &dev->geo;
	int ret, pg, pl;

	/* sense first page */
	ret = nvm_bb_chunk_sense(dev, ppa);
	if (ret < 0) /* io error */
		return ret;
	else if (ret == 0) /* valid data */
		meta->state = NVM_CHK_ST_OPEN;
	else if (ret > 0) {
		/*
		 * If empty page, the chunk is free, else it is an
		 * actual io error. In that case, mark it offline.
		 */
		switch (ret) {
		case NVM_RSP_ERR_EMPTYPAGE:
			meta->state = NVM_CHK_ST_FREE;
			return 0;
		case NVM_RSP_ERR_FAILCRC:
		case NVM_RSP_ERR_FAILECC:
		case NVM_RSP_WARN_HIGHECC:
			meta->state = NVM_CHK_ST_OPEN;
			goto scan;
		default:
			return -ret; /* other io error */
		}
	}

	/* sense last page */
	ppa.g.pg = geo->num_pg - 1;
	ppa.g.pl = geo->num_pln - 1;

	ret = nvm_bb_chunk_sense(dev, ppa);
	if (ret < 0) /* io error */
		return ret;
	else if (ret == 0) { /* Chunk fully written */
		meta->state = NVM_CHK_ST_CLOSED;
		meta->wp = geo->clba;
		return 0;
	} else if (ret > 0) {
		switch (ret) {
		case NVM_RSP_ERR_EMPTYPAGE:
		case NVM_RSP_ERR_FAILCRC:
		case NVM_RSP_ERR_FAILECC:
		case NVM_RSP_WARN_HIGHECC:
			meta->state = NVM_CHK_ST_OPEN;
			break;
		default:
			return -ret; /* other io error */
		}
	}

scan:
	/*
	 * chunk is open, we scan sequentially to update the write pointer.
	 * We make the assumption that targets write data across all planes
	 * before moving to the next page.
	 */
	for (pg = 0; pg < geo->num_pg; pg++) {
		for (pl = 0; pl < geo->num_pln; pl++) {
			ppa.g.pg = pg;
			ppa.g.pl = pl;

			ret = nvm_bb_chunk_sense(dev, ppa);
			if (ret < 0) /* io error */
				return ret;
			else if (ret == 0) {
				meta->wp += geo->ws_min;
			} else if (ret > 0) {
				switch (ret) {
				case NVM_RSP_ERR_EMPTYPAGE:
					return 0;
				case NVM_RSP_ERR_FAILCRC:
				case NVM_RSP_ERR_FAILECC:
				case NVM_RSP_WARN_HIGHECC:
					meta->wp += geo->ws_min;
					break;
				default:
					return -ret; /* other io error */
				}
			}
		}
	}

	return 0;
}

/*
 * folds a bad block list from its plane representation to its
 * chunk representation.
 *
 * If any of the planes status are bad or grown bad, the chunk is marked
 * offline. If not bad, the first plane state acts as the chunk state.
 */
static int nvm_bb_to_chunk(struct nvm_dev *dev, struct ppa_addr ppa,
			   u8 *blks, int nr_blks, struct nvm_chk_meta *meta)
{
	struct nvm_geo *geo = &dev->geo;
	int ret, blk, pl, offset, blktype;

	for (blk = 0; blk < geo->num_chk; blk++) {
		offset = blk * geo->pln_mode;
		blktype = blks[offset];

		for (pl = 0; pl < geo->pln_mode; pl++) {
			if (blks[offset + pl] &
					(NVM_BLK_T_BAD|NVM_BLK_T_GRWN_BAD)) {
				blktype = blks[offset + pl];
				break;
			}
		}

		ppa.g.blk = blk;

		meta->wp = 0;
		meta->type = NVM_CHK_TP_W_SEQ;
		meta->wi = 0;
		meta->slba = generic_to_dev_addr(dev, ppa).ppa;
		meta->cnlb = dev->geo.clba;

		if (blktype == NVM_BLK_T_FREE) {
			ret = nvm_bb_chunk_scan(dev, ppa, meta);
			if (ret)
				return ret;
		} else {
			meta->state = NVM_CHK_ST_OFFLINE;
		}

		meta++;
	}

	return 0;
}

static int nvm_get_bb_meta(struct nvm_dev *dev, sector_t slba,
			   int nchks, struct nvm_chk_meta *meta)
{
	struct nvm_geo *geo = &dev->geo;
	struct ppa_addr ppa;
	u8 *blks;
	int ch, lun, nr_blks;
	int ret;

	ppa.ppa = slba;
	ppa = dev_to_generic_addr(dev, ppa);

	if (ppa.g.blk != 0)
		return -EINVAL;

	if ((nchks % geo->num_chk) != 0)
		return -EINVAL;

	nr_blks = geo->num_chk * geo->pln_mode;

	blks = kmalloc(nr_blks, GFP_KERNEL);
	if (!blks)
		return -ENOMEM;

	for (ch = ppa.g.ch; ch < geo->num_ch; ch++) {
		for (lun = ppa.g.lun; lun < geo->num_lun; lun++) {
			struct ppa_addr ppa_gen, ppa_dev;

			if (!nchks)
				goto done;

			ppa_gen.ppa = 0;
			ppa_gen.g.ch = ch;
			ppa_gen.g.lun = lun;
			ppa_dev = generic_to_dev_addr(dev, ppa_gen);

			ret = dev->ops->get_bb_tbl(dev, ppa_dev, blks);
			if (ret)
				goto done;

			ret = nvm_bb_to_chunk(dev, ppa_gen, blks, nr_blks,
									meta);
			if (ret)
				goto done;

			meta += geo->num_chk;
			nchks -= geo->num_chk;
		}
	}
done:
	kfree(blks);
	return ret;
}

int nvm_get_chunk_meta(struct nvm_tgt_dev *tgt_dev, struct ppa_addr ppa,
		       int nchks, struct nvm_chk_meta *meta)
{
	struct nvm_dev *dev = tgt_dev->parent;

	nvm_ppa_tgt_to_dev(tgt_dev, &ppa, 1);

	if (dev->geo.version == NVM_OCSSD_SPEC_12)
		return nvm_get_bb_meta(dev, (sector_t)ppa.ppa, nchks, meta);

	return dev->ops->get_chk_meta(dev, (sector_t)ppa.ppa, nchks, meta);
}
EXPORT_SYMBOL_GPL(nvm_get_chunk_meta);

int nvm_set_chunk_meta(struct nvm_tgt_dev *tgt_dev, struct ppa_addr *ppas,
		       int nr_ppas, int type)
{
	struct nvm_dev *dev = tgt_dev->parent;
	struct nvm_rq rqd;
	int ret;

	if (dev->geo.version == NVM_OCSSD_SPEC_20)
		return 0;

	if (nr_ppas > NVM_MAX_VLBA) {
		pr_err("nvm: unable to update all blocks atomically\n");
		return -EINVAL;
	}

	memset(&rqd, 0, sizeof(struct nvm_rq));

	nvm_set_rqd_ppalist(tgt_dev, &rqd, ppas, nr_ppas);
	nvm_rq_tgt_to_dev(tgt_dev, &rqd);

	ret = dev->ops->set_bb_tbl(dev, &rqd.ppa_addr, rqd.nr_ppas, type);
	nvm_free_rqd_ppalist(tgt_dev, &rqd);
	if (ret)
		return -EINVAL;

	return 0;
}
EXPORT_SYMBOL_GPL(nvm_set_chunk_meta);

static int nvm_core_init(struct nvm_dev *dev)
{
	struct nvm_geo *geo = &dev->geo;
	int ret;

	dev->lun_map = kcalloc(BITS_TO_LONGS(geo->all_luns),
					sizeof(unsigned long), GFP_KERNEL);
	if (!dev->lun_map)
		return -ENOMEM;

	INIT_LIST_HEAD(&dev->area_list);
	INIT_LIST_HEAD(&dev->targets);
	mutex_init(&dev->mlock);
	spin_lock_init(&dev->lock);

	ret = nvm_register_map(dev);
	if (ret)
		goto err_fmtype;

	return 0;
err_fmtype:
	kfree(dev->lun_map);
	return ret;
}

static void nvm_free(struct nvm_dev *dev)
{
	if (!dev)
		return;

	if (dev->dma_pool)
		dev->ops->destroy_dma_pool(dev->dma_pool);

	nvm_unregister_map(dev);
	kfree(dev->lun_map);
	kfree(dev);
}

static int nvm_init(struct nvm_dev *dev)
{
	struct nvm_geo *geo = &dev->geo;
	int ret = -EINVAL;

	if (dev->ops->identity(dev)) {
		pr_err("nvm: device could not be identified\n");
		goto err;
	}

	pr_debug("nvm: ver:%u.%u nvm_vendor:%x\n",
				geo->major_ver_id, geo->minor_ver_id,
				geo->vmnt);

	ret = nvm_core_init(dev);
	if (ret) {
		pr_err("nvm: could not initialize core structures.\n");
		goto err;
	}

	pr_info("nvm: registered %s [%u/%u/%u/%u/%u]\n",
			dev->name, dev->geo.ws_min, dev->geo.ws_opt,
			dev->geo.num_chk, dev->geo.all_luns,
			dev->geo.num_ch);
	return 0;
err:
	pr_err("nvm: failed to initialize nvm\n");
	return ret;
}

struct nvm_dev *nvm_alloc_dev(int node)
{
	return kzalloc_node(sizeof(struct nvm_dev), GFP_KERNEL, node);
}
EXPORT_SYMBOL(nvm_alloc_dev);

int nvm_register(struct nvm_dev *dev)
{
	int ret;

	if (!dev->q || !dev->ops)
		return -EINVAL;

	dev->dma_pool = dev->ops->create_dma_pool(dev, "ppalist");
	if (!dev->dma_pool) {
		pr_err("nvm: could not create dma pool\n");
		return -ENOMEM;
	}

	ret = nvm_init(dev);
	if (ret)
		goto err_init;

	/* register device with a supported media manager */
	down_write(&nvm_lock);
	list_add(&dev->devices, &nvm_devices);
	up_write(&nvm_lock);

	return 0;
err_init:
	dev->ops->destroy_dma_pool(dev->dma_pool);
	return ret;
}
EXPORT_SYMBOL(nvm_register);

void nvm_unregister(struct nvm_dev *dev)
{
	struct nvm_target *t, *tmp;

	mutex_lock(&dev->mlock);
	list_for_each_entry_safe(t, tmp, &dev->targets, list) {
		if (t->dev->parent != dev)
			continue;
		__nvm_remove_target(t, false);
	}
	mutex_unlock(&dev->mlock);

	down_write(&nvm_lock);
	list_del(&dev->devices);
	up_write(&nvm_lock);

	nvm_free(dev);
}
EXPORT_SYMBOL(nvm_unregister);

static int __nvm_configure_create(struct nvm_ioctl_create *create)
{
	struct nvm_dev *dev;

	down_write(&nvm_lock);
	dev = nvm_find_nvm_dev(create->dev);
	up_write(&nvm_lock);

	if (!dev) {
		pr_err("nvm: device not found\n");
		return -EINVAL;
	}

	return nvm_create_tgt(dev, create);
}

static long nvm_ioctl_info(struct file *file, void __user *arg)
{
	struct nvm_ioctl_info *info;
	struct nvm_tgt_type *tt;
	int tgt_iter = 0;

	info = memdup_user(arg, sizeof(struct nvm_ioctl_info));
	if (IS_ERR(info))
		return -EFAULT;

	info->version[0] = NVM_VERSION_MAJOR;
	info->version[1] = NVM_VERSION_MINOR;
	info->version[2] = NVM_VERSION_PATCH;

	down_write(&nvm_tgtt_lock);
	list_for_each_entry(tt, &nvm_tgt_types, list) {
		struct nvm_ioctl_info_tgt *tgt = &info->tgts[tgt_iter];

		tgt->version[0] = tt->version[0];
		tgt->version[1] = tt->version[1];
		tgt->version[2] = tt->version[2];
		strncpy(tgt->tgtname, tt->name, NVM_TTYPE_NAME_MAX);

		tgt_iter++;
	}

	info->tgtsize = tgt_iter;
	up_write(&nvm_tgtt_lock);

	if (copy_to_user(arg, info, sizeof(struct nvm_ioctl_info))) {
		kfree(info);
		return -EFAULT;
	}

	kfree(info);
	return 0;
}

static long nvm_ioctl_get_devices(struct file *file, void __user *arg)
{
	struct nvm_ioctl_get_devices *devices;
	struct nvm_dev *dev;
	int i = 0;

	devices = kzalloc(sizeof(struct nvm_ioctl_get_devices), GFP_KERNEL);
	if (!devices)
		return -ENOMEM;

	down_write(&nvm_lock);
	list_for_each_entry(dev, &nvm_devices, devices) {
		struct nvm_ioctl_device_info *info = &devices->info[i];

		strlcpy(info->devname, dev->name, sizeof(info->devname));

		/* kept for compatibility */
		info->bmversion[0] = 1;
		info->bmversion[1] = 0;
		info->bmversion[2] = 0;
		strlcpy(info->bmname, "gennvm", sizeof(info->bmname));
		i++;

		if (i > 31) {
			pr_err("nvm: max 31 devices can be reported.\n");
			break;
		}
	}
	up_write(&nvm_lock);

	devices->nr_devices = i;

	if (copy_to_user(arg, devices,
			 sizeof(struct nvm_ioctl_get_devices))) {
		kfree(devices);
		return -EFAULT;
	}

	kfree(devices);
	return 0;
}

static long nvm_ioctl_dev_create(struct file *file, void __user *arg)
{
	struct nvm_ioctl_create create;

	if (copy_from_user(&create, arg, sizeof(struct nvm_ioctl_create)))
		return -EFAULT;

	if (create.conf.type == NVM_CONFIG_TYPE_EXTENDED &&
	    create.conf.e.rsv != 0) {
		pr_err("nvm: reserved config field in use\n");
		return -EINVAL;
	}

	create.dev[DISK_NAME_LEN - 1] = '\0';
	create.tgttype[NVM_TTYPE_NAME_MAX - 1] = '\0';
	create.tgtname[DISK_NAME_LEN - 1] = '\0';

	if (create.flags != 0) {
		__u32 flags = create.flags;

		/* Check for valid flags */
		if (flags & NVM_TARGET_FACTORY)
			flags &= ~NVM_TARGET_FACTORY;

		if (flags) {
			pr_err("nvm: flag not supported\n");
			return -EINVAL;
		}
	}

	return __nvm_configure_create(&create);
}

static long nvm_ioctl_dev_remove(struct file *file, void __user *arg)
{
	struct nvm_ioctl_remove remove;
	struct nvm_dev *dev;
	int ret = 0;

	if (copy_from_user(&remove, arg, sizeof(struct nvm_ioctl_remove)))
		return -EFAULT;

	remove.tgtname[DISK_NAME_LEN - 1] = '\0';

	if (remove.flags != 0) {
		pr_err("nvm: no flags supported\n");
		return -EINVAL;
	}

	list_for_each_entry(dev, &nvm_devices, devices) {
		ret = nvm_remove_tgt(dev, &remove);
		if (!ret)
			break;
	}

	return ret;
}

/* kept for compatibility reasons */
static long nvm_ioctl_dev_init(struct file *file, void __user *arg)
{
	struct nvm_ioctl_dev_init init;

	if (copy_from_user(&init, arg, sizeof(struct nvm_ioctl_dev_init)))
		return -EFAULT;

	if (init.flags != 0) {
		pr_err("nvm: no flags supported\n");
		return -EINVAL;
	}

	return 0;
}

/* Kept for compatibility reasons */
static long nvm_ioctl_dev_factory(struct file *file, void __user *arg)
{
	struct nvm_ioctl_dev_factory fact;

	if (copy_from_user(&fact, arg, sizeof(struct nvm_ioctl_dev_factory)))
		return -EFAULT;

	fact.dev[DISK_NAME_LEN - 1] = '\0';

	if (fact.flags & ~(NVM_FACTORY_NR_BITS - 1))
		return -EINVAL;

	return 0;
}

static long nvm_ctl_ioctl(struct file *file, uint cmd, unsigned long arg)
{
	void __user *argp = (void __user *)arg;

	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;

	switch (cmd) {
	case NVM_INFO:
		return nvm_ioctl_info(file, argp);
	case NVM_GET_DEVICES:
		return nvm_ioctl_get_devices(file, argp);
	case NVM_DEV_CREATE:
		return nvm_ioctl_dev_create(file, argp);
	case NVM_DEV_REMOVE:
		return nvm_ioctl_dev_remove(file, argp);
	case NVM_DEV_INIT:
		return nvm_ioctl_dev_init(file, argp);
	case NVM_DEV_FACTORY:
		return nvm_ioctl_dev_factory(file, argp);
	}
	return 0;
}

static const struct file_operations _ctl_fops = {
	.open = nonseekable_open,
	.unlocked_ioctl = nvm_ctl_ioctl,
	.owner = THIS_MODULE,
	.llseek  = noop_llseek,
};

static struct miscdevice _nvm_misc = {
	.minor		= MISC_DYNAMIC_MINOR,
	.name		= "lightnvm",
	.nodename	= "lightnvm/control",
	.fops		= &_ctl_fops,
};
builtin_misc_device(_nvm_misc);