/*
 * Copyright (C) 2015 IT University of Copenhagen (rrpc.h)
 * Copyright (C) 2016 CNEX Labs
 * Initial release: Matias Bjorling <matias@cnexlabs.com>
 * Write buffering: Javier Gonzalez <javier@cnexlabs.com>
 *
 * 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.
 *
 * Implementation of a Physical Block-device target for Open-channel SSDs.
 *
 */

#ifndef PBLK_H_
#define PBLK_H_

#include <linux/blkdev.h>
#include <linux/blk-mq.h>
#include <linux/bio.h>
#include <linux/module.h>
#include <linux/kthread.h>
#include <linux/vmalloc.h>
#include <linux/crc32.h>
#include <linux/uuid.h>

#include <linux/lightnvm.h>

/* Run only GC if less than 1/X blocks are free */
#define GC_LIMIT_INVERSE 5
#define GC_TIME_MSECS 1000

#define PBLK_SECTOR (512)
#define PBLK_EXPOSED_PAGE_SIZE (4096)
#define PBLK_MAX_REQ_ADDRS (64)
#define PBLK_MAX_REQ_ADDRS_PW (6)

#define PBLK_CACHE_NAME_LEN (DISK_NAME_LEN + 16)

#define PBLK_COMMAND_TIMEOUT_MS 30000

/* Max 512 LUNs per device */
#define PBLK_MAX_LUNS_BITMAP (4)

#define NR_PHY_IN_LOG (PBLK_EXPOSED_PAGE_SIZE / PBLK_SECTOR)

#define pblk_for_each_lun(pblk, rlun, i) \
                for ((i) = 0, rlun = &(pblk)->luns[0]; \
                        (i) < (pblk)->nr_luns; (i)++, rlun = &(pblk)->luns[(i)])

#define ERASE 2 /* READ = 0, WRITE = 1 */

enum {
        /* IO Types */
        PBLK_IOTYPE_USER        = 1 << 0,
        PBLK_IOTYPE_GC          = 1 << 1,

        /* Write buffer flags */
        PBLK_FLUSH_ENTRY        = 1 << 2,
        PBLK_WRITTEN_DATA       = 1 << 3,
        PBLK_SUBMITTED_ENTRY    = 1 << 4,
        PBLK_WRITABLE_ENTRY     = 1 << 5,
};

enum {
        PBLK_BLK_ST_OPEN =      0x1,
        PBLK_BLK_ST_CLOSED =    0x2,
};

/* The number of GC lists and the rate-limiter states go together. This way the
 * rate-limiter can dictate how much GC is needed based on resource utilization.
 */
#define PBLK_NR_GC_LISTS 3
#define PBLK_MAX_GC_JOBS 32

enum {
        PBLK_RL_HIGH = 1,
        PBLK_RL_MID = 2,
        PBLK_RL_LOW = 3,
};

struct pblk_sec_meta {
        u64 reserved;
        __le64 lba;
};

#define pblk_dma_meta_size (sizeof(struct pblk_sec_meta) * PBLK_MAX_REQ_ADDRS)

/* write completion context */
struct pblk_c_ctx {
        struct list_head list;          /* Head for out-of-order completion */

        unsigned long *lun_bitmap;      /* Luns used on current request */
        unsigned int sentry;
        unsigned int nr_valid;
        unsigned int nr_padded;
};

/* Read context */
struct pblk_r_ctx {
        struct bio *orig_bio;
};

/* Recovery context */
struct pblk_rec_ctx {
        struct pblk *pblk;
        struct nvm_rq *rqd;
        struct list_head failed;
        struct work_struct ws_rec;
};

/* Write context */
struct pblk_w_ctx {
        struct bio_list bios;           /* Original bios - used for completion
                                         * in REQ_FUA, REQ_FLUSH case
                                         */
        u64 lba;                        /* Logic addr. associated with entry */
        struct ppa_addr ppa;            /* Physic addr. associated with entry */
        int flags;                      /* Write context flags */
};

struct pblk_rb_entry {
        struct ppa_addr cacheline;      /* Cacheline for this entry */
        void *data;                     /* Pointer to data on this entry */
        struct pblk_w_ctx w_ctx;        /* Context for this entry */
        struct list_head index;         /* List head to enable indexes */
};

#define EMPTY_ENTRY (~0U)

struct pblk_rb_pages {
        struct page *pages;
        int order;
        struct list_head list;
};

struct pblk_rb {
        struct pblk_rb_entry *entries;  /* Ring buffer entries */
        unsigned int mem;               /* Write offset - points to next
                                         * writable entry in memory
                                         */
        unsigned int subm;              /* Read offset - points to last entry
                                         * that has been submitted to the media
                                         * to be persisted
                                         */
        unsigned int sync;              /* Synced - backpointer that signals
                                         * the last submitted entry that has
                                         * been successfully persisted to media
                                         */
        unsigned int sync_point;        /* Sync point - last entry that must be
                                         * flushed to the media. Used with
                                         * REQ_FLUSH and REQ_FUA
                                         */
        unsigned int l2p_update;        /* l2p update point - next entry for
                                         * which l2p mapping will be updated to
                                         * contain a device ppa address (instead
                                         * of a cacheline
                                         */
        unsigned int nr_entries;        /* Number of entries in write buffer -
                                         * must be a power of two
                                         */
        unsigned int seg_size;          /* Size of the data segments being
                                         * stored on each entry. Typically this
                                         * will be 4KB
                                         */

        struct list_head pages;         /* List of data pages */

        spinlock_t w_lock;              /* Write lock */
        spinlock_t s_lock;              /* Sync lock */

#ifdef CONFIG_NVM_DEBUG
        atomic_t inflight_sync_point;   /* Not served REQ_FLUSH | REQ_FUA */
#endif
};

#define PBLK_RECOVERY_SECTORS 16

struct pblk_lun {
        struct ppa_addr bppa;

        u8 *bb_list;                    /* Bad block list for LUN. Only used on
                                         * bring up. Bad blocks are managed
                                         * within lines on run-time.
                                         */

        struct semaphore wr_sem;
};

struct pblk_gc_rq {
        struct pblk_line *line;
        void *data;
        u64 *lba_list;
        int nr_secs;
        int secs_to_gc;
        struct list_head list;
};

struct pblk_gc {
        int gc_active;
        int gc_enabled;
        int gc_forced;
        int gc_jobs_active;
        atomic_t inflight_gc;

        struct task_struct *gc_ts;
        struct task_struct *gc_writer_ts;
        struct workqueue_struct *gc_reader_wq;
        struct timer_list gc_timer;

        int w_entries;
        struct list_head w_list;

        spinlock_t lock;
        spinlock_t w_lock;
};

struct pblk_rl {
        unsigned int high;      /* Upper threshold for rate limiter (free run -
                                 * user I/O rate limiter
                                 */
        unsigned int low;       /* Lower threshold for rate limiter (user I/O
                                 * rate limiter - stall)
                                 */
        unsigned int high_pw;   /* High rounded up as a power of 2 */

#define PBLK_USER_HIGH_THRS 2   /* Begin write limit at 50 percent
                                 * available blks
                                 */
#define PBLK_USER_LOW_THRS 20   /* Aggressive GC at 5% available blocks */

        int rb_windows_pw;      /* Number of rate windows in the write buffer
                                 * given as a power-of-2. This guarantees that
                                 * when user I/O is being rate limited, there
                                 * will be reserved enough space for the GC to
                                 * place its payload. A window is of
                                 * pblk->max_write_pgs size, which in NVMe is
                                 * 64, i.e., 256kb.
                                 */
        int rb_budget;          /* Total number of entries available for I/O */
        int rb_user_max;        /* Max buffer entries available for user I/O */
        atomic_t rb_user_cnt;   /* User I/O buffer counter */
        int rb_gc_max;          /* Max buffer entries available for GC I/O */
        int rb_gc_rsv;          /* Reserved buffer entries for GC I/O */
        int rb_state;           /* Rate-limiter current state */
        atomic_t rb_gc_cnt;     /* GC I/O buffer counter */

        int rb_user_active;
        struct timer_list u_timer;

        unsigned long long nr_secs;
        unsigned long total_blocks;
        atomic_t free_blocks;
};

#define PBLK_LINE_NR_LUN_BITMAP 2
#define PBLK_LINE_NR_SEC_BITMAP 2
#define PBLK_LINE_EMPTY (~0U)

enum {
        /* Line Types */
        PBLK_LINETYPE_FREE = 0,
        PBLK_LINETYPE_LOG = 1,
        PBLK_LINETYPE_DATA = 2,

        /* Line state */
        PBLK_LINESTATE_FREE = 10,
        PBLK_LINESTATE_OPEN = 11,
        PBLK_LINESTATE_CLOSED = 12,
        PBLK_LINESTATE_GC = 13,
        PBLK_LINESTATE_BAD = 14,
        PBLK_LINESTATE_CORRUPT = 15,

        /* GC group */
        PBLK_LINEGC_NONE = 20,
        PBLK_LINEGC_EMPTY = 21,
        PBLK_LINEGC_LOW = 22,
        PBLK_LINEGC_MID = 23,
        PBLK_LINEGC_HIGH = 24,
        PBLK_LINEGC_FULL = 25,
};

#define PBLK_MAGIC 0x70626c6b /*pblk*/

struct line_header {
        __le32 crc;
        __le32 identifier;      /* pblk identifier */
        __u8 uuid[16];          /* instance uuid */
        __le16 type;            /* line type */
        __le16 version;         /* type version */
        __le32 id;              /* line id for current line */
};

struct line_smeta {
        struct line_header header;

        __le32 crc;             /* Full structure including struct crc */
        /* Previous line metadata */
        __le32 prev_id;         /* Line id for previous line */

        /* Current line metadata */
        __le64 seq_nr;          /* Sequence number for current line */

        /* Active writers */
        __le32 window_wr_lun;   /* Number of parallel LUNs to write */

        __le32 rsvd[2];
};

/*
 * Metadata Layout:
 *      1. struct pblk_emeta
 *      2. nr_lbas u64 forming lba list
 *      3. nr_lines (all) u32 valid sector count (vsc) (~0U: non-alloc line)
 *      4. nr_luns bits (u64 format) forming line bad block bitmap
 *
 *      3. and 4. will be part of FTL log
 */
struct line_emeta {
        struct line_header header;

        __le32 crc;             /* Full structure including struct crc */

        /* Previous line metadata */
        __le32 prev_id;         /* Line id for prev line */

        /* Current line metadata */
        __le64 seq_nr;          /* Sequence number for current line */

        /* Active writers */
        __le32 window_wr_lun;   /* Number of parallel LUNs to write */

        /* Bookkeeping for recovery */
        __le32 next_id;         /* Line id for next line */
        __le64 nr_lbas;         /* Number of lbas mapped in line */
        __le64 nr_valid_lbas;   /* Number of valid lbas mapped in line */
};

struct pblk_line {
        struct pblk *pblk;
        unsigned int id;                /* Line number corresponds to the
                                         * block line
                                         */
        unsigned int seq_nr;            /* Unique line sequence number */

        int state;                      /* PBLK_LINESTATE_X */
        int type;                       /* PBLK_LINETYPE_X */
        int gc_group;                   /* PBLK_LINEGC_X */
        struct list_head list;          /* Free, GC lists */

        unsigned long *lun_bitmap;      /* Bitmap for LUNs mapped in line */

        struct line_smeta *smeta;       /* Start metadata */
        struct line_emeta *emeta;       /* End metadata */
        int meta_line;                  /* Metadata line id */
        u64 smeta_ssec;                 /* Sector where smeta starts */
        u64 emeta_ssec;                 /* Sector where emeta starts */

        unsigned int sec_in_line;       /* Number of usable secs in line */

        atomic_t blk_in_line;           /* Number of good blocks in line */
        unsigned long *blk_bitmap;      /* Bitmap for valid/invalid blocks */
        unsigned long *erase_bitmap;    /* Bitmap for erased blocks */

        unsigned long *map_bitmap;      /* Bitmap for mapped sectors in line */
        unsigned long *invalid_bitmap;  /* Bitmap for invalid sectors in line */

        atomic_t left_eblks;            /* Blocks left for erasing */
        atomic_t left_seblks;           /* Blocks left for sync erasing */

        int left_msecs;                 /* Sectors left for mapping */
        int left_ssecs;                 /* Sectors left to sync */
        unsigned int cur_sec;           /* Sector map pointer */
        unsigned int vsc;               /* Valid sector count in line */

        struct kref ref;                /* Write buffer L2P references */

        spinlock_t lock;                /* Necessary for invalid_bitmap only */
};

#define PBLK_DATA_LINES 4

enum{
        PBLK_KMALLOC_META = 1,
        PBLK_VMALLOC_META = 2,
};

struct pblk_line_metadata {
        void *meta;
};

struct pblk_line_mgmt {
        int nr_lines;                   /* Total number of full lines */
        int nr_free_lines;              /* Number of full lines in free list */

        /* Free lists - use free_lock */
        struct list_head free_list;     /* Full lines ready to use */
        struct list_head corrupt_list;  /* Full lines corrupted */
        struct list_head bad_list;      /* Full lines bad */

        /* GC lists - use gc_lock */
        struct list_head *gc_lists[PBLK_NR_GC_LISTS];
        struct list_head gc_high_list;  /* Full lines ready to GC, high isc */
        struct list_head gc_mid_list;   /* Full lines ready to GC, mid isc */
        struct list_head gc_low_list;   /* Full lines ready to GC, low isc */

        struct list_head gc_full_list;  /* Full lines ready to GC, no valid */
        struct list_head gc_empty_list; /* Full lines close, all valid */

        struct pblk_line *log_line;     /* Current FTL log line */
        struct pblk_line *data_line;    /* Current data line */
        struct pblk_line *log_next;     /* Next FTL log line */
        struct pblk_line *data_next;    /* Next data line */

        /* Metadata allocation type: VMALLOC | KMALLOC */
        int smeta_alloc_type;
        int emeta_alloc_type;

        /* Pre-allocated metadata for data lines */
        struct pblk_line_metadata sline_meta[PBLK_DATA_LINES];
        struct pblk_line_metadata eline_meta[PBLK_DATA_LINES];
        unsigned long meta_bitmap;

        /* Helpers for fast bitmap calculations */
        unsigned long *bb_template;
        unsigned long *bb_aux;

        unsigned long d_seq_nr;         /* Data line unique sequence number */
        unsigned long l_seq_nr;         /* Log line unique sequence number */

        spinlock_t free_lock;
        spinlock_t gc_lock;
};

struct pblk_line_meta {
        unsigned int smeta_len;         /* Total length for smeta */
        unsigned int smeta_sec;         /* Sectors needed for smeta*/
        unsigned int emeta_len;         /* Total length for emeta */
        unsigned int emeta_sec;         /* Sectors needed for emeta*/
        unsigned int emeta_bb;          /* Boundary for bb that affects emeta */
        unsigned int sec_bitmap_len;    /* Length for sector bitmap in line */
        unsigned int blk_bitmap_len;    /* Length for block bitmap in line */
        unsigned int lun_bitmap_len;    /* Length for lun bitmap in line */

        unsigned int blk_per_line;      /* Number of blocks in a full line */
        unsigned int sec_per_line;      /* Number of sectors in a line */
        unsigned int min_blk_line;      /* Min. number of good blocks in line */

        unsigned int mid_thrs;          /* Threshold for GC mid list */
        unsigned int high_thrs;         /* Threshold for GC high list */
};

struct pblk_addr_format {
        u64     ch_mask;
        u64     lun_mask;
        u64     pln_mask;
        u64     blk_mask;
        u64     pg_mask;
        u64     sec_mask;
        u8      ch_offset;
        u8      lun_offset;
        u8      pln_offset;
        u8      blk_offset;
        u8      pg_offset;
        u8      sec_offset;
};

struct pblk {
        struct nvm_tgt_dev *dev;
        struct gendisk *disk;

        struct kobject kobj;

        struct pblk_lun *luns;

        struct pblk_line *lines;                /* Line array */
        struct pblk_line_mgmt l_mg;             /* Line management */
        struct pblk_line_meta lm;               /* Line metadata */

        int ppaf_bitsize;
        struct pblk_addr_format ppaf;

        struct pblk_rb rwb;

        int min_write_pgs; /* Minimum amount of pages required by controller */
        int max_write_pgs; /* Maximum amount of pages supported by controller */
        int pgs_in_buffer; /* Number of pages that need to be held in buffer to
                            * guarantee successful reads.
                            */

        sector_t capacity; /* Device capacity when bad blocks are subtracted */
        int over_pct;      /* Percentage of device used for over-provisioning */

        /* pblk provisioning values. Used by rate limiter */
        struct pblk_rl rl;

        struct semaphore erase_sem;

        unsigned char instance_uuid[16];
#ifdef CONFIG_NVM_DEBUG
        /* All debug counters apply to 4kb sector I/Os */
        atomic_long_t inflight_writes;  /* Inflight writes (user and gc) */
        atomic_long_t padded_writes;    /* Sectors padded due to flush/fua */
        atomic_long_t padded_wb;        /* Sectors padded in write buffer */
        atomic_long_t nr_flush;         /* Number of flush/fua I/O */
        atomic_long_t req_writes;       /* Sectors stored on write buffer */
        atomic_long_t sub_writes;       /* Sectors submitted from buffer */
        atomic_long_t sync_writes;      /* Sectors synced to media */
        atomic_long_t compl_writes;     /* Sectors completed in write bio */
        atomic_long_t inflight_reads;   /* Inflight sector read requests */
        atomic_long_t sync_reads;       /* Completed sector read requests */
        atomic_long_t recov_writes;     /* Sectors submitted from recovery */
        atomic_long_t recov_gc_writes;  /* Sectors submitted from write GC */
        atomic_long_t recov_gc_reads;   /* Sectors submitted from read GC */
#endif

        spinlock_t lock;

        atomic_long_t read_failed;
        atomic_long_t read_empty;
        atomic_long_t read_high_ecc;
        atomic_long_t read_failed_gc;
        atomic_long_t write_failed;
        atomic_long_t erase_failed;

        struct task_struct *writer_ts;

        /* Simple translation map of logical addresses to physical addresses.
         * The logical addresses is known by the host system, while the physical
         * addresses are used when writing to the disk block device.
         */
        unsigned char *trans_map;
        spinlock_t trans_lock;

        struct list_head compl_list;

        mempool_t *page_pool;
        mempool_t *line_ws_pool;
        mempool_t *rec_pool;
        mempool_t *r_rq_pool;
        mempool_t *w_rq_pool;
        mempool_t *line_meta_pool;

        struct workqueue_struct *kw_wq;
        struct timer_list wtimer;

        struct pblk_gc gc;
};

struct pblk_line_ws {
        struct pblk *pblk;
        struct pblk_line *line;
        void *priv;
        struct work_struct ws;
};

#define pblk_r_rq_size (sizeof(struct nvm_rq) + sizeof(struct pblk_r_ctx))
#define pblk_w_rq_size (sizeof(struct nvm_rq) + sizeof(struct pblk_c_ctx))

/*
 * pblk ring buffer operations
 */
int pblk_rb_init(struct pblk_rb *rb, struct pblk_rb_entry *rb_entry_base,
                 unsigned int power_size, unsigned int power_seg_sz);
unsigned int pblk_rb_calculate_size(unsigned int nr_entries);
void *pblk_rb_entries_ref(struct pblk_rb *rb);
int pblk_rb_may_write_user(struct pblk_rb *rb, struct bio *bio,
                           unsigned int nr_entries, unsigned int *pos);
int pblk_rb_may_write_gc(struct pblk_rb *rb, unsigned int nr_entries,
                         unsigned int *pos);
void pblk_rb_write_entry_user(struct pblk_rb *rb, void *data,
                              struct pblk_w_ctx w_ctx, unsigned int pos);
void pblk_rb_write_entry_gc(struct pblk_rb *rb, void *data,
                            struct pblk_w_ctx w_ctx, struct pblk_line *gc_line,
                            unsigned int pos);
struct pblk_w_ctx *pblk_rb_w_ctx(struct pblk_rb *rb, unsigned int pos);

void pblk_rb_sync_l2p(struct pblk_rb *rb);
unsigned int pblk_rb_read_to_bio(struct pblk_rb *rb, struct bio *bio,
                                 struct pblk_c_ctx *c_ctx,
                                 unsigned int pos,
                                 unsigned int nr_entries,
                                 unsigned int count);
unsigned int pblk_rb_read_to_bio_list(struct pblk_rb *rb, struct bio *bio,
                                      struct list_head *list,
                                      unsigned int max);
int pblk_rb_copy_to_bio(struct pblk_rb *rb, struct bio *bio, sector_t lba,
                        u64 pos, int bio_iter);
unsigned int pblk_rb_read_commit(struct pblk_rb *rb, unsigned int entries);

unsigned int pblk_rb_sync_init(struct pblk_rb *rb, unsigned long *flags);
unsigned int pblk_rb_sync_advance(struct pblk_rb *rb, unsigned int nr_entries);
struct pblk_rb_entry *pblk_rb_sync_scan_entry(struct pblk_rb *rb,
                                              struct ppa_addr *ppa);
void pblk_rb_sync_end(struct pblk_rb *rb, unsigned long *flags);
unsigned int pblk_rb_sync_point_count(struct pblk_rb *rb);

unsigned int pblk_rb_read_count(struct pblk_rb *rb);
unsigned int pblk_rb_wrap_pos(struct pblk_rb *rb, unsigned int pos);

int pblk_rb_tear_down_check(struct pblk_rb *rb);
int pblk_rb_pos_oob(struct pblk_rb *rb, u64 pos);
void pblk_rb_data_free(struct pblk_rb *rb);
ssize_t pblk_rb_sysfs(struct pblk_rb *rb, char *buf);

/*
 * pblk core
 */
struct nvm_rq *pblk_alloc_rqd(struct pblk *pblk, int rw);
int pblk_setup_w_rec_rq(struct pblk *pblk, struct nvm_rq *rqd,
                        struct pblk_c_ctx *c_ctx);
void pblk_free_rqd(struct pblk *pblk, struct nvm_rq *rqd, int rw);
void pblk_flush_writer(struct pblk *pblk);
struct ppa_addr pblk_get_lba_map(struct pblk *pblk, sector_t lba);
void pblk_discard(struct pblk *pblk, struct bio *bio);
void pblk_log_write_err(struct pblk *pblk, struct nvm_rq *rqd);
void pblk_log_read_err(struct pblk *pblk, struct nvm_rq *rqd);
int pblk_submit_io(struct pblk *pblk, struct nvm_rq *rqd);
struct bio *pblk_bio_map_addr(struct pblk *pblk, void *data,
                              unsigned int nr_secs, unsigned int len,
                              gfp_t gfp_mask);
struct pblk_line *pblk_line_get(struct pblk *pblk);
struct pblk_line *pblk_line_get_first_data(struct pblk *pblk);
struct pblk_line *pblk_line_replace_data(struct pblk *pblk);
int pblk_line_recov_alloc(struct pblk *pblk, struct pblk_line *line);
void pblk_line_recov_close(struct pblk *pblk, struct pblk_line *line);
struct pblk_line *pblk_line_get_data(struct pblk *pblk);
struct pblk_line *pblk_line_get_data_next(struct pblk *pblk);
int pblk_line_erase(struct pblk *pblk, struct pblk_line *line);
int pblk_line_is_full(struct pblk_line *line);
void pblk_line_free(struct pblk *pblk, struct pblk_line *line);
void pblk_line_close_ws(struct work_struct *work);
void pblk_line_close(struct pblk *pblk, struct pblk_line *line);
void pblk_line_mark_bb(struct work_struct *work);
void pblk_line_run_ws(struct pblk *pblk, struct pblk_line *line, void *priv,
                      void (*work)(struct work_struct *));
u64 pblk_line_smeta_start(struct pblk *pblk, struct pblk_line *line);
int pblk_line_read_smeta(struct pblk *pblk, struct pblk_line *line);
int pblk_line_read_emeta(struct pblk *pblk, struct pblk_line *line);
int pblk_blk_erase_async(struct pblk *pblk, struct ppa_addr erase_ppa);
void pblk_line_put(struct kref *ref);
struct list_head *pblk_line_gc_list(struct pblk *pblk, struct pblk_line *line);
u64 pblk_alloc_page(struct pblk *pblk, struct pblk_line *line, int nr_secs);
int pblk_calc_secs(struct pblk *pblk, unsigned long secs_avail,
                   unsigned long secs_to_flush);
void pblk_down_rq(struct pblk *pblk, struct ppa_addr *ppa_list, int nr_ppas,
                  unsigned long *lun_bitmap);
void pblk_up_rq(struct pblk *pblk, struct ppa_addr *ppa_list, int nr_ppas,
                unsigned long *lun_bitmap);
void pblk_end_bio_sync(struct bio *bio);
void pblk_end_io_sync(struct nvm_rq *rqd);
int pblk_bio_add_pages(struct pblk *pblk, struct bio *bio, gfp_t flags,
                       int nr_pages);
void pblk_map_pad_invalidate(struct pblk *pblk, struct pblk_line *line,
                             u64 paddr);
void pblk_bio_free_pages(struct pblk *pblk, struct bio *bio, int off,
                         int nr_pages);
void pblk_map_invalidate(struct pblk *pblk, struct ppa_addr ppa);
void pblk_update_map(struct pblk *pblk, sector_t lba, struct ppa_addr ppa);
void pblk_update_map_cache(struct pblk *pblk, sector_t lba,
                           struct ppa_addr ppa);
void pblk_update_map_dev(struct pblk *pblk, sector_t lba,
                         struct ppa_addr ppa, struct ppa_addr entry_line);
int pblk_update_map_gc(struct pblk *pblk, sector_t lba, struct ppa_addr ppa,
                       struct pblk_line *gc_line);
void pblk_lookup_l2p_rand(struct pblk *pblk, struct ppa_addr *ppas,
                          u64 *lba_list, int nr_secs);
void pblk_lookup_l2p_seq(struct pblk *pblk, struct ppa_addr *ppas,
                         sector_t blba, int nr_secs);

/*
 * pblk user I/O write path
 */
int pblk_write_to_cache(struct pblk *pblk, struct bio *bio,
                        unsigned long flags);
int pblk_write_gc_to_cache(struct pblk *pblk, void *data, u64 *lba_list,
                           unsigned int nr_entries, unsigned int nr_rec_entries,
                           struct pblk_line *gc_line, unsigned long flags);

/*
 * pblk map
 */
void pblk_map_erase_rq(struct pblk *pblk, struct nvm_rq *rqd,
                       unsigned int sentry, unsigned long *lun_bitmap,
                       unsigned int valid_secs, struct ppa_addr *erase_ppa);
void pblk_map_rq(struct pblk *pblk, struct nvm_rq *rqd, unsigned int sentry,
                 unsigned long *lun_bitmap, unsigned int valid_secs,
                 unsigned int off);

/*
 * pblk write thread
 */
int pblk_write_ts(void *data);
void pblk_write_timer_fn(unsigned long data);
void pblk_write_should_kick(struct pblk *pblk);

/*
 * pblk read path
 */
int pblk_submit_read(struct pblk *pblk, struct bio *bio);
int pblk_submit_read_gc(struct pblk *pblk, u64 *lba_list, void *data,
                        unsigned int nr_secs, unsigned int *secs_to_gc,
                        struct pblk_line *line);
/*
 * pblk recovery
 */
void pblk_submit_rec(struct work_struct *work);
struct pblk_line *pblk_recov_l2p(struct pblk *pblk);
void pblk_recov_pad(struct pblk *pblk);
__le64 *pblk_recov_get_lba_list(struct pblk *pblk, struct line_emeta *emeta);
int pblk_recov_setup_rq(struct pblk *pblk, struct pblk_c_ctx *c_ctx,
                        struct pblk_rec_ctx *recovery, u64 *comp_bits,
                        unsigned int comp);

/*
 * pblk gc
 */
#define PBLK_GC_TRIES 3

int pblk_gc_init(struct pblk *pblk);
void pblk_gc_exit(struct pblk *pblk);
void pblk_gc_should_start(struct pblk *pblk);
void pblk_gc_should_stop(struct pblk *pblk);
int pblk_gc_status(struct pblk *pblk);
void pblk_gc_sysfs_state_show(struct pblk *pblk, int *gc_enabled,
                              int *gc_active);
void pblk_gc_sysfs_force(struct pblk *pblk, int force);

/*
 * pblk rate limiter
 */
void pblk_rl_init(struct pblk_rl *rl, int budget);
void pblk_rl_free(struct pblk_rl *rl);
int pblk_rl_gc_thrs(struct pblk_rl *rl);
unsigned long pblk_rl_nr_free_blks(struct pblk_rl *rl);
int pblk_rl_user_may_insert(struct pblk_rl *rl, int nr_entries);
void pblk_rl_user_in(struct pblk_rl *rl, int nr_entries);
int pblk_rl_gc_may_insert(struct pblk_rl *rl, int nr_entries);
void pblk_rl_gc_in(struct pblk_rl *rl, int nr_entries);
void pblk_rl_out(struct pblk_rl *rl, int nr_user, int nr_gc);
void pblk_rl_set_gc_rsc(struct pblk_rl *rl, int rsv);
int pblk_rl_sysfs_rate_show(struct pblk_rl *rl);
void pblk_rl_free_lines_inc(struct pblk_rl *rl, struct pblk_line *line);
void pblk_rl_free_lines_dec(struct pblk_rl *rl, struct pblk_line *line);

/*
 * pblk sysfs
 */
int pblk_sysfs_init(struct gendisk *tdisk);
void pblk_sysfs_exit(struct gendisk *tdisk);

static inline void *pblk_malloc(size_t size, int type, gfp_t flags)
{
        if (type == PBLK_KMALLOC_META)
                return kmalloc(size, flags);
        return vmalloc(size);
}

static inline void pblk_mfree(void *ptr, int type)
{
        if (type == PBLK_KMALLOC_META)
                kfree(ptr);
        else
                vfree(ptr);
}

static inline struct nvm_rq *nvm_rq_from_c_ctx(void *c_ctx)
{
        return c_ctx - sizeof(struct nvm_rq);
}

static inline void *pblk_line_emeta_to_lbas(struct line_emeta *emeta)
{
        return (emeta) + 1;
}

#define NVM_MEM_PAGE_WRITE (8)

static inline int pblk_pad_distance(struct pblk *pblk)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;

        return NVM_MEM_PAGE_WRITE * geo->nr_luns * geo->sec_per_pl;
}

static inline int pblk_dev_ppa_to_line(struct ppa_addr p)
{
        return p.g.blk;
}

static inline int pblk_tgt_ppa_to_line(struct ppa_addr p)
{
        return p.g.blk;
}

static inline int pblk_ppa_to_pos(struct nvm_geo *geo, struct ppa_addr p)
{
        return p.g.lun * geo->nr_chnls + p.g.ch;
}

/* A block within a line corresponds to the lun */
static inline int pblk_dev_ppa_to_pos(struct nvm_geo *geo, struct ppa_addr p)
{
        return p.g.lun * geo->nr_chnls + p.g.ch;
}

static inline struct ppa_addr pblk_ppa32_to_ppa64(struct pblk *pblk, u32 ppa32)
{
        struct ppa_addr ppa64;

        ppa64.ppa = 0;

        if (ppa32 == -1) {
                ppa64.ppa = ADDR_EMPTY;
        } else if (ppa32 & (1U << 31)) {
                ppa64.c.line = ppa32 & ((~0U) >> 1);
                ppa64.c.is_cached = 1;
        } else {
                ppa64.g.blk = (ppa32 & pblk->ppaf.blk_mask) >>
                                                        pblk->ppaf.blk_offset;
                ppa64.g.pg = (ppa32 & pblk->ppaf.pg_mask) >>
                                                        pblk->ppaf.pg_offset;
                ppa64.g.lun = (ppa32 & pblk->ppaf.lun_mask) >>
                                                        pblk->ppaf.lun_offset;
                ppa64.g.ch = (ppa32 & pblk->ppaf.ch_mask) >>
                                                        pblk->ppaf.ch_offset;
                ppa64.g.pl = (ppa32 & pblk->ppaf.pln_mask) >>
                                                        pblk->ppaf.pln_offset;
                ppa64.g.sec = (ppa32 & pblk->ppaf.sec_mask) >>
                                                        pblk->ppaf.sec_offset;
        }

        return ppa64;
}

static inline struct ppa_addr pblk_trans_map_get(struct pblk *pblk,
                                                                sector_t lba)
{
        struct ppa_addr ppa;

        if (pblk->ppaf_bitsize < 32) {
                u32 *map = (u32 *)pblk->trans_map;

                ppa = pblk_ppa32_to_ppa64(pblk, map[lba]);
        } else {
                struct ppa_addr *map = (struct ppa_addr *)pblk->trans_map;

                ppa = map[lba];
        }

        return ppa;
}

static inline u32 pblk_ppa64_to_ppa32(struct pblk *pblk, struct ppa_addr ppa64)
{
        u32 ppa32 = 0;

        if (ppa64.ppa == ADDR_EMPTY) {
                ppa32 = ~0U;
        } else if (ppa64.c.is_cached) {
                ppa32 |= ppa64.c.line;
                ppa32 |= 1U << 31;
        } else {
                ppa32 |= ppa64.g.blk << pblk->ppaf.blk_offset;
                ppa32 |= ppa64.g.pg << pblk->ppaf.pg_offset;
                ppa32 |= ppa64.g.lun << pblk->ppaf.lun_offset;
                ppa32 |= ppa64.g.ch << pblk->ppaf.ch_offset;
                ppa32 |= ppa64.g.pl << pblk->ppaf.pln_offset;
                ppa32 |= ppa64.g.sec << pblk->ppaf.sec_offset;
        }

        return ppa32;
}

static inline void pblk_trans_map_set(struct pblk *pblk, sector_t lba,
                                                struct ppa_addr ppa)
{
        if (pblk->ppaf_bitsize < 32) {
                u32 *map = (u32 *)pblk->trans_map;

                map[lba] = pblk_ppa64_to_ppa32(pblk, ppa);
        } else {
                u64 *map = (u64 *)pblk->trans_map;

                map[lba] = ppa.ppa;
        }
}

static inline u64 pblk_dev_ppa_to_line_addr(struct pblk *pblk,
                                                        struct ppa_addr p)
{
        u64 paddr;

        paddr = 0;
        paddr |= (u64)p.g.pg << pblk->ppaf.pg_offset;
        paddr |= (u64)p.g.lun << pblk->ppaf.lun_offset;
        paddr |= (u64)p.g.ch << pblk->ppaf.ch_offset;
        paddr |= (u64)p.g.pl << pblk->ppaf.pln_offset;
        paddr |= (u64)p.g.sec << pblk->ppaf.sec_offset;

        return paddr;
}

static inline int pblk_ppa_empty(struct ppa_addr ppa_addr)
{
        return (ppa_addr.ppa == ADDR_EMPTY);
}

static inline void pblk_ppa_set_empty(struct ppa_addr *ppa_addr)
{
        ppa_addr->ppa = ADDR_EMPTY;
}

static inline int pblk_addr_in_cache(struct ppa_addr ppa)
{
        return (ppa.ppa != ADDR_EMPTY && ppa.c.is_cached);
}

static inline int pblk_addr_to_cacheline(struct ppa_addr ppa)
{
        return ppa.c.line;
}

static inline struct ppa_addr pblk_cacheline_to_addr(int addr)
{
        struct ppa_addr p;

        p.c.line = addr;
        p.c.is_cached = 1;

        return p;
}

static inline struct ppa_addr addr_to_gen_ppa(struct pblk *pblk, u64 paddr,
                                              u64 line_id)
{
        struct ppa_addr ppa;

        ppa.ppa = 0;
        ppa.g.blk = line_id;
        ppa.g.pg = (paddr & pblk->ppaf.pg_mask) >> pblk->ppaf.pg_offset;
        ppa.g.lun = (paddr & pblk->ppaf.lun_mask) >> pblk->ppaf.lun_offset;
        ppa.g.ch = (paddr & pblk->ppaf.ch_mask) >> pblk->ppaf.ch_offset;
        ppa.g.pl = (paddr & pblk->ppaf.pln_mask) >> pblk->ppaf.pln_offset;
        ppa.g.sec = (paddr & pblk->ppaf.sec_mask) >> pblk->ppaf.sec_offset;

        return ppa;
}

static inline struct ppa_addr addr_to_pblk_ppa(struct pblk *pblk, u64 paddr,
                                         u64 line_id)
{
        struct ppa_addr ppa;

        ppa = addr_to_gen_ppa(pblk, paddr, line_id);

        return ppa;
}

static inline u32 pblk_calc_meta_header_crc(struct pblk *pblk,
                                            struct line_smeta *smeta)
{
        u32 crc = ~(u32)0;

        crc = crc32_le(crc, (unsigned char *)smeta + sizeof(crc),
                                sizeof(struct line_header) - sizeof(crc));

        return crc;
}

static inline u32 pblk_calc_smeta_crc(struct pblk *pblk,
                                      struct line_smeta *smeta)
{
        struct pblk_line_meta *lm = &pblk->lm;
        u32 crc = ~(u32)0;

        crc = crc32_le(crc, (unsigned char *)smeta +
                                sizeof(struct line_header) + sizeof(crc),
                                lm->smeta_len -
                                sizeof(struct line_header) - sizeof(crc));

        return crc;
}

static inline u32 pblk_calc_emeta_crc(struct pblk *pblk,
                                      struct line_emeta *emeta)
{
        struct pblk_line_meta *lm = &pblk->lm;
        u32 crc = ~(u32)0;

        crc = crc32_le(crc, (unsigned char *)emeta +
                                sizeof(struct line_header) + sizeof(crc),
                                lm->emeta_len -
                                sizeof(struct line_header) - sizeof(crc));

        return crc;
}

static inline int pblk_set_progr_mode(struct pblk *pblk, int type)
{
        struct nvm_tgt_dev *dev = pblk->dev;
        struct nvm_geo *geo = &dev->geo;
        int flags;

        flags = geo->plane_mode >> 1;

        if (type == WRITE)
                flags |= NVM_IO_SCRAMBLE_ENABLE;

        return flags;
}

static inline int pblk_set_read_mode(struct pblk *pblk)
{
        return NVM_IO_SNGL_ACCESS | NVM_IO_SUSPEND | NVM_IO_SCRAMBLE_ENABLE;
}

#ifdef CONFIG_NVM_DEBUG
static inline void print_ppa(struct ppa_addr *p, char *msg, int error)
{
        if (p->c.is_cached) {
                pr_err("ppa: (%s: %x) cache line: %llu\n",
                                msg, error, (u64)p->c.line);
        } else {
                pr_err("ppa: (%s: %x):ch:%d,lun:%d,blk:%d,pg:%d,pl:%d,sec:%d\n",
                        msg, error,
                        p->g.ch, p->g.lun, p->g.blk,
                        p->g.pg, p->g.pl, p->g.sec);
        }
}

static inline void pblk_print_failed_rqd(struct pblk *pblk, struct nvm_rq *rqd,
                                         int error)
{
        int bit = -1;

        if (rqd->nr_ppas ==  1) {
                print_ppa(&rqd->ppa_addr, "rqd", error);
                return;
        }

        while ((bit = find_next_bit((void *)&rqd->ppa_status, rqd->nr_ppas,
                                                bit + 1)) < rqd->nr_ppas) {
                print_ppa(&rqd->ppa_list[bit], "rqd", error);
        }

        pr_err("error:%d, ppa_status:%llx\n", error, rqd->ppa_status);
}
#endif

static inline int pblk_boundary_ppa_checks(struct nvm_tgt_dev *tgt_dev,
                                       struct ppa_addr *ppas, int nr_ppas)
{
        struct nvm_geo *geo = &tgt_dev->geo;
        struct ppa_addr *ppa;
        int i;

        for (i = 0; i < nr_ppas; i++) {
                ppa = &ppas[i];

                if (!ppa->c.is_cached &&
                                ppa->g.ch < geo->nr_chnls &&
                                ppa->g.lun < geo->luns_per_chnl &&
                                ppa->g.pl < geo->nr_planes &&
                                ppa->g.blk < geo->blks_per_lun &&
                                ppa->g.pg < geo->pgs_per_blk &&
                                ppa->g.sec < geo->sec_per_pg)
                        continue;

#ifdef CONFIG_NVM_DEBUG
                print_ppa(ppa, "boundary", i);
#endif
                return 1;
        }
        return 0;
}

static inline int pblk_boundary_paddr_checks(struct pblk *pblk, u64 paddr)
{
        struct pblk_line_meta *lm = &pblk->lm;

        if (paddr > lm->sec_per_line)
                return 1;

        return 0;
}

static inline unsigned int pblk_get_bi_idx(struct bio *bio)
{
        return bio->bi_iter.bi_idx;
}

static inline sector_t pblk_get_lba(struct bio *bio)
{
        return bio->bi_iter.bi_sector / NR_PHY_IN_LOG;
}

static inline unsigned int pblk_get_secs(struct bio *bio)
{
        return  bio->bi_iter.bi_size / PBLK_EXPOSED_PAGE_SIZE;
}

static inline sector_t pblk_get_sector(sector_t lba)
{
        return lba * NR_PHY_IN_LOG;
}

static inline void pblk_setup_uuid(struct pblk *pblk)
{
        uuid_le uuid;

        uuid_le_gen(&uuid);
        memcpy(pblk->instance_uuid, uuid.b, 16);
}
#endif /* PBLK_H_ */