/*
 * ST M25P80 emulator. Emulate all SPI flash devices based on the m25p80 command
 * set. Known devices table current as of Jun/2012 and taken from linux.
 * See drivers/mtd/devices/m25p80.c.
 *
 * Copyright (C) 2011 Edgar E. Iglesias <edgar.iglesias@gmail.com>
 * Copyright (C) 2012 Peter A. G. Crosthwaite <peter.crosthwaite@petalogix.com>
 * Copyright (C) 2012 PetaLogix
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 or
 * (at your option) a later version of the License.
 *
 * 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; if not, see <http://www.gnu.org/licenses/>.
 */

#include "hw/hw.h"
#include "sysemu/blockdev.h"
#include "hw/ssi.h"
#include "hw/devices.h"

#ifdef M25P80_ERR_DEBUG
#define DB_PRINT(...) do { \
    fprintf(stderr,  ": %s: ", __func__); \
    fprintf(stderr, ## __VA_ARGS__); \
    } while (0);
#else
    #define DB_PRINT(...)
#endif

/* Fields for FlashPartInfo->flags */

/* erase capabilities */
#define ER_4K 1
#define ER_32K 2
/* set to allow the page program command to write 0s back to 1. Useful for
 * modelling EEPROM with SPI flash command set
 */
#define WR_1 0x100

typedef struct FlashPartInfo {
    const char *part_name;
    /* jedec code. (jedec >> 16) & 0xff is the 1st byte, >> 8 the 2nd etc */
    uint32_t jedec;
    /* extended jedec code */
    uint16_t ext_jedec;
    /* there is confusion between manufacturers as to what a sector is. In this
     * device model, a "sector" is the size that is erased by the ERASE_SECTOR
     * command (opcode 0xd8).
     */
    uint32_t sector_size;
    uint32_t n_sectors;
    uint32_t page_size;
    uint8_t flags;
} FlashPartInfo;

/* adapted from linux */

#define INFO(_part_name, _jedec, _ext_jedec, _sector_size, _n_sectors, _flags)\
    .part_name = (_part_name),\
    .jedec = (_jedec),\
    .ext_jedec = (_ext_jedec),\
    .sector_size = (_sector_size),\
    .n_sectors = (_n_sectors),\
    .page_size = 256,\
    .flags = (_flags),\

#define JEDEC_NUMONYX 0x20
#define JEDEC_WINBOND 0xEF
#define JEDEC_SPANSION 0x01

static const FlashPartInfo known_devices[] = {
    /* Atmel -- some are (confusingly) marketed as "DataFlash" */
    { INFO("at25fs010",   0x1f6601,      0,  32 << 10,   4, ER_4K) },
    { INFO("at25fs040",   0x1f6604,      0,  64 << 10,   8, ER_4K) },

    { INFO("at25df041a",  0x1f4401,      0,  64 << 10,   8, ER_4K) },
    { INFO("at25df321a",  0x1f4701,      0,  64 << 10,  64, ER_4K) },
    { INFO("at25df641",   0x1f4800,      0,  64 << 10, 128, ER_4K) },

    { INFO("at26f004",    0x1f0400,      0,  64 << 10,   8, ER_4K) },
    { INFO("at26df081a",  0x1f4501,      0,  64 << 10,  16, ER_4K) },
    { INFO("at26df161a",  0x1f4601,      0,  64 << 10,  32, ER_4K) },
    { INFO("at26df321",   0x1f4700,      0,  64 << 10,  64, ER_4K) },

    /* EON -- en25xxx */
    { INFO("en25f32",     0x1c3116,      0,  64 << 10,  64, ER_4K) },
    { INFO("en25p32",     0x1c2016,      0,  64 << 10,  64, 0) },
    { INFO("en25q32b",    0x1c3016,      0,  64 << 10,  64, 0) },
    { INFO("en25p64",     0x1c2017,      0,  64 << 10, 128, 0) },

    /* Intel/Numonyx -- xxxs33b */
    { INFO("160s33b",     0x898911,      0,  64 << 10,  32, 0) },
    { INFO("320s33b",     0x898912,      0,  64 << 10,  64, 0) },
    { INFO("640s33b",     0x898913,      0,  64 << 10, 128, 0) },

    /* Macronix */
    { INFO("mx25l4005a",  0xc22013,      0,  64 << 10,   8, ER_4K) },
    { INFO("mx25l8005",   0xc22014,      0,  64 << 10,  16, 0) },
    { INFO("mx25l1606e",  0xc22015,      0,  64 << 10,  32, ER_4K) },
    { INFO("mx25l3205d",  0xc22016,      0,  64 << 10,  64, 0) },
    { INFO("mx25l6405d",  0xc22017,      0,  64 << 10, 128, 0) },
    { INFO("mx25l12805d", 0xc22018,      0,  64 << 10, 256, 0) },
    { INFO("mx25l12855e", 0xc22618,      0,  64 << 10, 256, 0) },
    { INFO("mx25l25635e", 0xc22019,      0,  64 << 10, 512, 0) },
    { INFO("mx25l25655e", 0xc22619,      0,  64 << 10, 512, 0) },

    /* Spansion -- single (large) sector size only, at least
     * for the chips listed here (without boot sectors).
     */
    { INFO("s25sl004a",   0x010212,      0,  64 << 10,   8, 0) },
    { INFO("s25sl008a",   0x010213,      0,  64 << 10,  16, 0) },
    { INFO("s25sl016a",   0x010214,      0,  64 << 10,  32, 0) },
    { INFO("s25sl032a",   0x010215,      0,  64 << 10,  64, 0) },
    { INFO("s25sl032p",   0x010215, 0x4d00,  64 << 10,  64, ER_4K) },
    { INFO("s25sl064a",   0x010216,      0,  64 << 10, 128, 0) },
    { INFO("s25fl256s0",  0x010219, 0x4d00, 256 << 10, 128, 0) },
    { INFO("s25fl256s1",  0x010219, 0x4d01,  64 << 10, 512, 0) },
    { INFO("s25fl512s",   0x010220, 0x4d00, 256 << 10, 256, 0) },
    { INFO("s70fl01gs",   0x010221, 0x4d00, 256 << 10, 256, 0) },
    { INFO("s25sl12800",  0x012018, 0x0300, 256 << 10,  64, 0) },
    { INFO("s25sl12801",  0x012018, 0x0301,  64 << 10, 256, 0) },
    { INFO("s25fl129p0",  0x012018, 0x4d00, 256 << 10,  64, 0) },
    { INFO("s25fl129p1",  0x012018, 0x4d01,  64 << 10, 256, 0) },
    { INFO("s25fl016k",   0xef4015,      0,  64 << 10,  32, ER_4K | ER_32K) },
    { INFO("s25fl064k",   0xef4017,      0,  64 << 10, 128, ER_4K | ER_32K) },

    /* SST -- large erase sizes are "overlays", "sectors" are 4<< 10 */
    { INFO("sst25vf040b", 0xbf258d,      0,  64 << 10,   8, ER_4K) },
    { INFO("sst25vf080b", 0xbf258e,      0,  64 << 10,  16, ER_4K) },
    { INFO("sst25vf016b", 0xbf2541,      0,  64 << 10,  32, ER_4K) },
    { INFO("sst25vf032b", 0xbf254a,      0,  64 << 10,  64, ER_4K) },
    { INFO("sst25wf512",  0xbf2501,      0,  64 << 10,   1, ER_4K) },
    { INFO("sst25wf010",  0xbf2502,      0,  64 << 10,   2, ER_4K) },
    { INFO("sst25wf020",  0xbf2503,      0,  64 << 10,   4, ER_4K) },
    { INFO("sst25wf040",  0xbf2504,      0,  64 << 10,   8, ER_4K) },

    /* ST Microelectronics -- newer production may have feature updates */
    { INFO("m25p05",      0x202010,      0,  32 << 10,   2, 0) },
    { INFO("m25p10",      0x202011,      0,  32 << 10,   4, 0) },
    { INFO("m25p20",      0x202012,      0,  64 << 10,   4, 0) },
    { INFO("m25p40",      0x202013,      0,  64 << 10,   8, 0) },
    { INFO("m25p80",      0x202014,      0,  64 << 10,  16, 0) },
    { INFO("m25p16",      0x202015,      0,  64 << 10,  32, 0) },
    { INFO("m25p32",      0x202016,      0,  64 << 10,  64, 0) },
    { INFO("m25p64",      0x202017,      0,  64 << 10, 128, 0) },
    { INFO("m25p128",     0x202018,      0, 256 << 10,  64, 0) },

    { INFO("m45pe10",     0x204011,      0,  64 << 10,   2, 0) },
    { INFO("m45pe80",     0x204014,      0,  64 << 10,  16, 0) },
    { INFO("m45pe16",     0x204015,      0,  64 << 10,  32, 0) },

    { INFO("m25pe80",     0x208014,      0,  64 << 10,  16, 0) },
    { INFO("m25pe16",     0x208015,      0,  64 << 10,  32, ER_4K) },

    { INFO("m25px32",     0x207116,      0,  64 << 10,  64, ER_4K) },
    { INFO("m25px32-s0",  0x207316,      0,  64 << 10,  64, ER_4K) },
    { INFO("m25px32-s1",  0x206316,      0,  64 << 10,  64, ER_4K) },
    { INFO("m25px64",     0x207117,      0,  64 << 10, 128, 0) },

    /* Winbond -- w25x "blocks" are 64k, "sectors" are 4KiB */
    { INFO("w25x10",      0xef3011,      0,  64 << 10,   2, ER_4K) },
    { INFO("w25x20",      0xef3012,      0,  64 << 10,   4, ER_4K) },
    { INFO("w25x40",      0xef3013,      0,  64 << 10,   8, ER_4K) },
    { INFO("w25x80",      0xef3014,      0,  64 << 10,  16, ER_4K) },
    { INFO("w25x16",      0xef3015,      0,  64 << 10,  32, ER_4K) },
    { INFO("w25x32",      0xef3016,      0,  64 << 10,  64, ER_4K) },
    { INFO("w25q32",      0xef4016,      0,  64 << 10,  64, ER_4K) },
    { INFO("w25x64",      0xef3017,      0,  64 << 10, 128, ER_4K) },
    { INFO("w25q64",      0xef4017,      0,  64 << 10, 128, ER_4K) },

    /* Numonyx -- n25q128 */
    { INFO("n25q128",      0x20ba18,      0,  64 << 10, 256, 0) },
};

typedef enum {
    NOP = 0,
    WRSR = 0x1,
    WRDI = 0x4,
    RDSR = 0x5,
    WREN = 0x6,
    JEDEC_READ = 0x9f,
    BULK_ERASE = 0xc7,

    READ = 0x3,
    FAST_READ = 0xb,
    DOR = 0x3b,
    QOR = 0x6b,
    DIOR = 0xbb,
    QIOR = 0xeb,

    PP = 0x2,
    DPP = 0xa2,
    QPP = 0x32,

    ERASE_4K = 0x20,
    ERASE_32K = 0x52,
    ERASE_SECTOR = 0xd8,
} FlashCMD;

typedef enum {
    STATE_IDLE,
    STATE_PAGE_PROGRAM,
    STATE_READ,
    STATE_COLLECTING_DATA,
    STATE_READING_DATA,
} CMDState;

typedef struct Flash {
    SSISlave ssidev;
    uint32_t r;

    BlockDriverState *bdrv;

    uint8_t *storage;
    uint32_t size;
    int page_size;

    uint8_t state;
    uint8_t data[16];
    uint32_t len;
    uint32_t pos;
    uint8_t needed_bytes;
    uint8_t cmd_in_progress;
    uint64_t cur_addr;
    bool write_enable;

    int64_t dirty_page;

    const FlashPartInfo *pi;

} Flash;

typedef struct M25P80Class {
    SSISlaveClass parent_class;
    FlashPartInfo *pi;
} M25P80Class;

#define TYPE_M25P80 "m25p80-generic"
#define M25P80(obj) \
     OBJECT_CHECK(Flash, (obj), TYPE_M25P80)
#define M25P80_CLASS(klass) \
     OBJECT_CLASS_CHECK(M25P80Class, (klass), TYPE_M25P80)
#define M25P80_GET_CLASS(obj) \
     OBJECT_GET_CLASS(M25P80Class, (obj), TYPE_M25P80)

static void bdrv_sync_complete(void *opaque, int ret)
{
    /* do nothing. Masters do not directly interact with the backing store,
     * only the working copy so no mutexing required.
     */
}

static void flash_sync_page(Flash *s, int page)
{
    if (s->bdrv) {
        int bdrv_sector, nb_sectors;
        QEMUIOVector iov;

        bdrv_sector = (page * s->pi->page_size) / BDRV_SECTOR_SIZE;
        nb_sectors = DIV_ROUND_UP(s->pi->page_size, BDRV_SECTOR_SIZE);
        qemu_iovec_init(&iov, 1);
        qemu_iovec_add(&iov, s->storage + bdrv_sector * BDRV_SECTOR_SIZE,
                                                nb_sectors * BDRV_SECTOR_SIZE);
        bdrv_aio_writev(s->bdrv, bdrv_sector, &iov, nb_sectors,
                                                bdrv_sync_complete, NULL);
    }
}

static inline void flash_sync_area(Flash *s, int64_t off, int64_t len)
{
    int64_t start, end, nb_sectors;
    QEMUIOVector iov;

    if (!s->bdrv) {
        return;
    }

    assert(!(len % BDRV_SECTOR_SIZE));
    start = off / BDRV_SECTOR_SIZE;
    end = (off + len) / BDRV_SECTOR_SIZE;
    nb_sectors = end - start;
    qemu_iovec_init(&iov, 1);
    qemu_iovec_add(&iov, s->storage + (start * BDRV_SECTOR_SIZE),
                                        nb_sectors * BDRV_SECTOR_SIZE);
    bdrv_aio_writev(s->bdrv, start, &iov, nb_sectors, bdrv_sync_complete, NULL);
}

static void flash_erase(Flash *s, int offset, FlashCMD cmd)
{
    uint32_t len;
    uint8_t capa_to_assert = 0;

    switch (cmd) {
    case ERASE_4K:
        len = 4 << 10;
        capa_to_assert = ER_4K;
        break;
    case ERASE_32K:
        len = 32 << 10;
        capa_to_assert = ER_32K;
        break;
    case ERASE_SECTOR:
        len = s->pi->sector_size;
        break;
    case BULK_ERASE:
        len = s->size;
        break;
    default:
        abort();
    }

    DB_PRINT("offset = %#x, len = %d\n", offset, len);
    if ((s->pi->flags & capa_to_assert) != capa_to_assert) {
        hw_error("m25p80: %dk erase size not supported by device\n", len);
    }

    if (!s->write_enable) {
        DB_PRINT("erase with write protect!\n");
        return;
    }
    memset(s->storage + offset, 0xff, len);
    flash_sync_area(s, offset, len);
}

static inline void flash_sync_dirty(Flash *s, int64_t newpage)
{
    if (s->dirty_page >= 0 && s->dirty_page != newpage) {
        flash_sync_page(s, s->dirty_page);
        s->dirty_page = newpage;
    }
}

static inline
void flash_write8(Flash *s, uint64_t addr, uint8_t data)
{
    int64_t page = addr / s->pi->page_size;
    uint8_t prev = s->storage[s->cur_addr];

    if (!s->write_enable) {
        DB_PRINT("write with write protect!\n");
    }

    if ((prev ^ data) & data) {
        DB_PRINT("programming zero to one! addr=%lx  %x -> %x\n",
                  addr, prev, data);
    }

    if (s->pi->flags & WR_1) {
        s->storage[s->cur_addr] = data;
    } else {
        s->storage[s->cur_addr] &= data;
    }

    flash_sync_dirty(s, page);
    s->dirty_page = page;
}

static void complete_collecting_data(Flash *s)
{
    s->cur_addr = s->data[0] << 16;
    s->cur_addr |= s->data[1] << 8;
    s->cur_addr |= s->data[2];

    s->state = STATE_IDLE;

    switch (s->cmd_in_progress) {
    case DPP:
    case QPP:
    case PP:
        s->state = STATE_PAGE_PROGRAM;
        break;
    case READ:
    case FAST_READ:
    case DOR:
    case QOR:
    case DIOR:
    case QIOR:
        s->state = STATE_READ;
        break;
    case ERASE_4K:
    case ERASE_32K:
    case ERASE_SECTOR:
        flash_erase(s, s->cur_addr, s->cmd_in_progress);
        break;
    case WRSR:
        if (s->write_enable) {
            s->write_enable = false;
        }
        break;
    default:
        break;
    }
}

static void decode_new_cmd(Flash *s, uint32_t value)
{
    s->cmd_in_progress = value;
    DB_PRINT("decoded new command:%x\n", value);

    switch (value) {

    case ERASE_4K:
    case ERASE_32K:
    case ERASE_SECTOR:
    case READ:
    case DPP:
    case QPP:
    case PP:
        s->needed_bytes = 3;
        s->pos = 0;
        s->len = 0;
        s->state = STATE_COLLECTING_DATA;
        break;

    case FAST_READ:
    case DOR:
    case QOR:
        s->needed_bytes = 4;
        s->pos = 0;
        s->len = 0;
        s->state = STATE_COLLECTING_DATA;
        break;

    case DIOR:
        switch ((s->pi->jedec >> 16) & 0xFF) {
        case JEDEC_WINBOND:
        case JEDEC_SPANSION:
            s->needed_bytes = 4;
            break;
        case JEDEC_NUMONYX:
        default:
            s->needed_bytes = 5;
        }
        s->pos = 0;
        s->len = 0;
        s->state = STATE_COLLECTING_DATA;
        break;

    case QIOR:
        switch ((s->pi->jedec >> 16) & 0xFF) {
        case JEDEC_WINBOND:
        case JEDEC_SPANSION:
            s->needed_bytes = 6;
            break;
        case JEDEC_NUMONYX:
        default:
            s->needed_bytes = 8;
        }
        s->pos = 0;
        s->len = 0;
        s->state = STATE_COLLECTING_DATA;
        break;

    case WRSR:
        if (s->write_enable) {
            s->needed_bytes = 1;
            s->pos = 0;
            s->len = 0;
            s->state = STATE_COLLECTING_DATA;
        }
        break;

    case WRDI:
        s->write_enable = false;
        break;
    case WREN:
        s->write_enable = true;
        break;

    case RDSR:
        s->data[0] = (!!s->write_enable) << 1;
        s->pos = 0;
        s->len = 1;
        s->state = STATE_READING_DATA;
        break;

    case JEDEC_READ:
        DB_PRINT("populated jedec code\n");
        s->data[0] = (s->pi->jedec >> 16) & 0xff;
        s->data[1] = (s->pi->jedec >> 8) & 0xff;
        s->data[2] = s->pi->jedec & 0xff;
        if (s->pi->ext_jedec) {
            s->data[3] = (s->pi->ext_jedec >> 8) & 0xff;
            s->data[4] = s->pi->ext_jedec & 0xff;
            s->len = 5;
        } else {
            s->len = 3;
        }
        s->pos = 0;
        s->state = STATE_READING_DATA;
        break;

    case BULK_ERASE:
        if (s->write_enable) {
            DB_PRINT("chip erase\n");
            flash_erase(s, 0, BULK_ERASE);
        } else {
            DB_PRINT("chip erase with write protect!\n");
        }
        break;
    case NOP:
        break;
    default:
        DB_PRINT("Unknown cmd %x\n", value);
        break;
    }
}

static int m25p80_cs(SSISlave *ss, bool select)
{
    Flash *s = FROM_SSI_SLAVE(Flash, ss);

    if (select) {
        s->len = 0;
        s->pos = 0;
        s->state = STATE_IDLE;
        flash_sync_dirty(s, -1);
    }

    DB_PRINT("%sselect\n", select ? "de" : "");

    return 0;
}

static uint32_t m25p80_transfer8(SSISlave *ss, uint32_t tx)
{
    Flash *s = FROM_SSI_SLAVE(Flash, ss);
    uint32_t r = 0;

    switch (s->state) {

    case STATE_PAGE_PROGRAM:
        DB_PRINT("page program cur_addr=%lx data=%x\n", s->cur_addr,
                 (uint8_t)tx);
        flash_write8(s, s->cur_addr, (uint8_t)tx);
        s->cur_addr++;
        break;

    case STATE_READ:
        r = s->storage[s->cur_addr];
        DB_PRINT("READ 0x%lx=%x\n", s->cur_addr, r);
        s->cur_addr = (s->cur_addr + 1) % s->size;
        break;

    case STATE_COLLECTING_DATA:
        s->data[s->len] = (uint8_t)tx;
        s->len++;

        if (s->len == s->needed_bytes) {
            complete_collecting_data(s);
        }
        break;

    case STATE_READING_DATA:
        r = s->data[s->pos];
        s->pos++;
        if (s->pos == s->len) {
            s->pos = 0;
            s->state = STATE_IDLE;
        }
        break;

    default:
    case STATE_IDLE:
        decode_new_cmd(s, (uint8_t)tx);
        break;
    }

    return r;
}

static int m25p80_init(SSISlave *ss)
{
    DriveInfo *dinfo;
    Flash *s = FROM_SSI_SLAVE(Flash, ss);
    M25P80Class *mc = M25P80_GET_CLASS(s);

    s->pi = mc->pi;

    s->size = s->pi->sector_size * s->pi->n_sectors;
    s->dirty_page = -1;
    s->storage = qemu_blockalign(s->bdrv, s->size);

    dinfo = drive_get_next(IF_MTD);

    if (dinfo && dinfo->bdrv) {
        DB_PRINT("Binding to IF_MTD drive\n");
        s->bdrv = dinfo->bdrv;
        /* FIXME: Move to late init */
        if (bdrv_read(s->bdrv, 0, s->storage, DIV_ROUND_UP(s->size,
                                                    BDRV_SECTOR_SIZE))) {
            fprintf(stderr, "Failed to initialize SPI flash!\n");
            return 1;
        }
    } else {
        memset(s->storage, 0xFF, s->size);
    }

    return 0;
}

static void m25p80_pre_save(void *opaque)
{
    flash_sync_dirty((Flash *)opaque, -1);
}

static const VMStateDescription vmstate_m25p80 = {
    .name = "xilinx_spi",
    .version_id = 1,
    .minimum_version_id = 1,
    .minimum_version_id_old = 1,
    .pre_save = m25p80_pre_save,
    .fields = (VMStateField[]) {
        VMSTATE_UINT8(state, Flash),
        VMSTATE_UINT8_ARRAY(data, Flash, 16),
        VMSTATE_UINT32(len, Flash),
        VMSTATE_UINT32(pos, Flash),
        VMSTATE_UINT8(needed_bytes, Flash),
        VMSTATE_UINT8(cmd_in_progress, Flash),
        VMSTATE_UINT64(cur_addr, Flash),
        VMSTATE_BOOL(write_enable, Flash),
        VMSTATE_END_OF_LIST()
    }
};

static void m25p80_class_init(ObjectClass *klass, void *data)
{
    DeviceClass *dc = DEVICE_CLASS(klass);
    SSISlaveClass *k = SSI_SLAVE_CLASS(klass);
    M25P80Class *mc = M25P80_CLASS(klass);

    k->init = m25p80_init;
    k->transfer = m25p80_transfer8;
    k->set_cs = m25p80_cs;
    k->cs_polarity = SSI_CS_LOW;
    dc->vmsd = &vmstate_m25p80;
    mc->pi = data;
}

static const TypeInfo m25p80_info = {
    .name           = TYPE_M25P80,
    .parent         = TYPE_SSI_SLAVE,
    .instance_size  = sizeof(Flash),
    .class_size     = sizeof(M25P80Class),
    .abstract       = true,
};

static void m25p80_register_types(void)
{
    int i;

    type_register_static(&m25p80_info);
    for (i = 0; i < ARRAY_SIZE(known_devices); ++i) {
        TypeInfo ti = {
            .name       = known_devices[i].part_name,
            .parent     = TYPE_M25P80,
            .class_init = m25p80_class_init,
            .class_data = (void *)&known_devices[i],
        };
        type_register(&ti);
    }
}

type_init(m25p80_register_types)