/*

 *  CFI parallel flash with Intel command set emulation

 *

 *  Copyright (c) 2006 Thorsten Zitterell

 *  Copyright (c) 2005 Jocelyn Mayer

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library 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

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

/*

 * For now, this code can emulate flashes of 1, 2 or 4 bytes width.

 * Supported commands/modes are:

 * - flash read

 * - flash write

 * - flash ID read

 * - sector erase

 * - CFI queries

 *

 * It does not support timings

 * It does not support flash interleaving

 * It does not implement software data protection as found in many real chips

 * It does not implement erase suspend/resume commands

 * It does not implement multiple sectors erase

 *

 * It does not implement much more ...

 */

#include "hw.h"

#include "flash.h"

#include "block.h"

#include "qemu-timer.h"

#define PFLASH_BUG(fmt, args...) \

do { \

    printf("PFLASH: Possible BUG - " fmt, ##args); \

    exit(1); \

} while(0)

/* #define PFLASH_DEBUG */

#ifdef PFLASH_DEBUG

#define DPRINTF(fmt, args...)                      \

do {                                               \

        printf("PFLASH: " fmt , ##args);           \

} while (0)

#else

#define DPRINTF(fmt, args...) do { } while (0)

#endif

struct pflash_t {

    BlockDriverState *bs;

    target_ulong base;

    target_ulong sector_len;

    target_ulong total_len;

    int width;

    int wcycle; /* if 0, the flash is read normally */

    int bypass;

    int ro;

    uint8_t cmd;

    uint8_t status;

    uint16_t ident[4];

    uint8_t cfi_len;

    uint8_t cfi_table[0x52];

    target_ulong counter;

    QEMUTimer *timer;

    ram_addr_t off;

    int fl_mem;

    void *storage;

};

static void pflash_timer (void *opaque)

{

    pflash_t *pfl = opaque;

    DPRINTF("%s: command %02x done\n", __func__, pfl->cmd);

    /* Reset flash */

    pfl->status ^= 0x80;

    if (pfl->bypass) {

        pfl->wcycle = 2;

    } else {

        cpu_register_physical_memory(pfl->base, pfl->total_len,

                        pfl->off | IO_MEM_ROMD | pfl->fl_mem);

        pfl->wcycle = 0;

    }

    pfl->cmd = 0;

}

static uint32_t pflash_read (pflash_t *pfl, target_ulong offset, int width)

{

    target_ulong boff;

    uint32_t ret;

    uint8_t *p;

    ret = -1;

    boff = offset & 0xFF; /* why this here ?? */

    if (pfl->width == 2)

        boff = boff >> 1;

    else if (pfl->width == 4)

        boff = boff >> 2;

    DPRINTF("%s: reading offset " TARGET_FMT_lx " under cmd %02x width %d\n",

            __func__, offset, pfl->cmd, width);

    switch (pfl->cmd) {

    case 0x00:

        /* Flash area read */

        p = pfl->storage;

        switch (width) {

        case 1:

            ret = p[offset];

            DPRINTF("%s: data offset " TARGET_FMT_lx " %02x\n",

                    __func__, offset, ret);

            break;

        case 2:

#if defined(TARGET_WORDS_BIGENDIAN)

            ret = p[offset] << 8;

            ret |= p[offset + 1];

#else

            ret = p[offset];

            ret |= p[offset + 1] << 8;

#endif

            DPRINTF("%s: data offset " TARGET_FMT_lx " %04x\n",

                    __func__, offset, ret);

            break;

        case 4:

#if defined(TARGET_WORDS_BIGENDIAN)

            ret = p[offset] << 24;

            ret |= p[offset + 1] << 16;

            ret |= p[offset + 2] << 8;

            ret |= p[offset + 3];

#else

            ret = p[offset];

            ret |= p[offset + 1] << 8;

            ret |= p[offset + 1] << 8;

            ret |= p[offset + 2] << 16;

            ret |= p[offset + 3] << 24;

#endif

            DPRINTF("%s: data offset " TARGET_FMT_lx " %08x\n",

                    __func__, offset, ret);

            break;

        default:

            DPRINTF("BUG in %s\n", __func__);

        }

        break;

    case 0x20: /* Block erase */

    case 0x50: /* Clear status register */

    case 0x60: /* Block /un)lock */

    case 0x70: /* Status Register */

    case 0xe8: /* Write block */

        /* Status register read */

        ret = pfl->status;

        DPRINTF("%s: status %x\n", __func__, ret);

        break;

    case 0x98: /* Query mode */

        if (boff > pfl->cfi_len)

            ret = 0;

        else

            ret = pfl->cfi_table[boff];

        break;

    default:

        /* This should never happen : reset state & treat it as a read */

        DPRINTF("%s: unknown command state: %x\n", __func__, pfl->cmd);

        pfl->wcycle = 0;

        pfl->cmd = 0;

    }

    return ret;

}

/* update flash content on disk */

static void pflash_update(pflash_t *pfl, int offset,

                          int size)

{

    int offset_end;

    if (pfl->bs) {

        offset_end = offset + size;

        /* round to sectors */

        offset = offset >> 9;

        offset_end = (offset_end + 511) >> 9;

        bdrv_write(pfl->bs, offset, pfl->storage + (offset << 9),

                   offset_end - offset);

    }

}

static void inline pflash_data_write(pflash_t *pfl, target_ulong offset,

                          uint32_t value, int width)

{

    uint8_t *p = pfl->storage;

    DPRINTF("%s: block write offset " TARGET_FMT_lx

            " value %x counter " TARGET_FMT_lx "\n",

            __func__, offset, value, pfl->counter);

    switch (width) {

    case 1:

        p[offset] = value;

        pflash_update(pfl, offset, 1);

        break;

    case 2:

#if defined(TARGET_WORDS_BIGENDIAN)

        p[offset] = value >> 8;

        p[offset + 1] = value;

#else

        p[offset] = value;

        p[offset + 1] = value >> 8;

#endif

        pflash_update(pfl, offset, 2);

        break;

    case 4:

#if defined(TARGET_WORDS_BIGENDIAN)

        p[offset] = value >> 24;

        p[offset + 1] = value >> 16;

        p[offset + 2] = value >> 8;

        p[offset + 3] = value;

#else

        p[offset] = value;

        p[offset + 1] = value >> 8;

        p[offset + 2] = value >> 16;

        p[offset + 3] = value >> 24;

#endif

        pflash_update(pfl, offset, 4);

        break;

    }

}

static void pflash_write (pflash_t *pfl, target_ulong offset, uint32_t value,

                          int width)

{

    target_ulong boff;

    uint8_t *p;

    uint8_t cmd;

    cmd = value;

    DPRINTF("%s: writing offset " TARGET_FMT_lx " value %08x width %d wcycle 0x%x\n",

            __func__, offset, value, width, pfl->wcycle);

    /* Set the device in I/O access mode */

    cpu_register_physical_memory(pfl->base, pfl->total_len, pfl->fl_mem);

    boff = offset & (pfl->sector_len - 1);

    if (pfl->width == 2)

        boff = boff >> 1;

    else if (pfl->width == 4)

        boff = boff >> 2;

    switch (pfl->wcycle) {

    case 0:

        /* read mode */

        switch (cmd) {

        case 0x00: /* ??? */

            goto reset_flash;

        case 0x10: /* Single Byte Program */

        case 0x40: /* Single Byte Program */

            DPRINTF(stderr, "%s: Single Byte Program\n", __func__);

            break;

        case 0x20: /* Block erase */

            p = pfl->storage;

            offset &= ~(pfl->sector_len - 1);

            DPRINTF("%s: block erase at " TARGET_FMT_lx " bytes "

                    TARGET_FMT_lx "\n",

                    __func__, offset, pfl->sector_len);

            memset(p + offset, 0xff, pfl->sector_len);

            pflash_update(pfl, offset, pfl->sector_len);

            pfl->status |= 0x80; /* Ready! */

            break;

        case 0x50: /* Clear status bits */

            DPRINTF("%s: Clear status bits\n", __func__);

            pfl->status = 0x0;

            goto reset_flash;

        case 0x60: /* Block (un)lock */

            DPRINTF("%s: Block unlock\n", __func__);

            break;

        case 0x70: /* Status Register */

            DPRINTF("%s: Read status register\n", __func__);

            pfl->cmd = cmd;

            return;

        case 0x98: /* CFI query */

            DPRINTF("%s: CFI query\n", __func__);

            break;

        case 0xe8: /* Write to buffer */

            DPRINTF("%s: Write to buffer\n", __func__);

            pfl->status |= 0x80; /* Ready! */

            break;

        case 0xff: /* Read array mode */

            DPRINTF("%s: Read array mode\n", __func__);

            goto reset_flash;

        default:

            goto error_flash;

        }

        pfl->wcycle++;

        pfl->cmd = cmd;

        return;

    case 1:

        switch (pfl->cmd) {

        case 0x10: /* Single Byte Program */

        case 0x40: /* Single Byte Program */

            DPRINTF("%s: Single Byte Program\n", __func__);

            pflash_data_write(pfl, offset, value, width);

            pfl->status |= 0x80; /* Ready! */

            pfl->wcycle = 0;

        break;

        case 0x20: /* Block erase */

        case 0x28:

            if (cmd == 0xd0) { /* confirm */

                pfl->wcycle = 0;

                pfl->status |= 0x80;

            } else if (cmd == 0xff) { /* read array mode */

                goto reset_flash;

            } else

                goto error_flash;

            break;

        case 0xe8:

            DPRINTF("%s: block write of %x bytes\n", __func__, value);

            pfl->counter = value;

            pfl->wcycle++;

            break;

        case 0x60:

            if (cmd == 0xd0) {

                pfl->wcycle = 0;

                pfl->status |= 0x80;

            } else if (cmd == 0x01) {

                pfl->wcycle = 0;

                pfl->status |= 0x80;

            } else if (cmd == 0xff) {

                goto reset_flash;

            } else {

                DPRINTF("%s: Unknown (un)locking command\n", __func__);

                goto reset_flash;

            }

            break;

        case 0x98:

            if (cmd == 0xff) {

                goto reset_flash;

            } else {

                DPRINTF("%s: leaving query mode\n", __func__);

            }

            break;

        default:

            goto error_flash;

        }

        return;

    case 2:

        switch (pfl->cmd) {

        case 0xe8: /* Block write */

            pflash_data_write(pfl, offset, value, width);

            pfl->status |= 0x80;

            if (!pfl->counter) {

                DPRINTF("%s: block write finished\n", __func__);

                pfl->wcycle++;

            }

            pfl->counter--;

            break;

        default:

            goto error_flash;

        }

        return;

    case 3: /* Confirm mode */

        switch (pfl->cmd) {

        case 0xe8: /* Block write */

            if (cmd == 0xd0) {

                pfl->wcycle = 0;

                pfl->status |= 0x80;

            } else {

                DPRINTF("%s: unknown command for \"write block\"\n", __func__);

                PFLASH_BUG("Write block confirm");

                goto reset_flash;

            }

            break;

        default:

            goto error_flash;

        }

        return;

    default:

        /* Should never happen */

        DPRINTF("%s: invalid write state\n",  __func__);

        goto reset_flash;

    }

    return;

 error_flash:

    printf("%s: Unimplemented flash cmd sequence "

           "(offset " TARGET_FMT_lx ", wcycle 0x%x cmd 0x%x value 0x%x)\n",

           __func__, offset, pfl->wcycle, pfl->cmd, value);

 reset_flash:

    cpu_register_physical_memory(pfl->base, pfl->total_len,

                    pfl->off | IO_MEM_ROMD | pfl->fl_mem);

    pfl->bypass = 0;

    pfl->wcycle = 0;

    pfl->cmd = 0;

    return;

}

static uint32_t pflash_readb (void *opaque, target_phys_addr_t addr)

{

    return pflash_read(opaque, addr, 1);

}

static uint32_t pflash_readw (void *opaque, target_phys_addr_t addr)

{

    pflash_t *pfl = opaque;

    return pflash_read(pfl, addr, 2);

}

static uint32_t pflash_readl (void *opaque, target_phys_addr_t addr)

{

    pflash_t *pfl = opaque;

    return pflash_read(pfl, addr, 4);

}

static void pflash_writeb (void *opaque, target_phys_addr_t addr,

                           uint32_t value)

{

    pflash_write(opaque, addr, value, 1);

}

static void pflash_writew (void *opaque, target_phys_addr_t addr,

                           uint32_t value)

{

    pflash_t *pfl = opaque;

    pflash_write(pfl, addr, value, 2);

}

static void pflash_writel (void *opaque, target_phys_addr_t addr,

                           uint32_t value)

{

    pflash_t *pfl = opaque;

    pflash_write(pfl, addr, value, 4);

}

static CPUWriteMemoryFunc *pflash_write_ops[] = {

    &pflash_writeb,

    &pflash_writew,

    &pflash_writel,

};

static CPUReadMemoryFunc *pflash_read_ops[] = {

    &pflash_readb,

    &pflash_readw,

    &pflash_readl,

};

/* Count trailing zeroes of a 32 bits quantity */

static int ctz32 (uint32_t n)

{

    int ret;

    ret = 0;

    if (!(n & 0xFFFF)) {

        ret += 16;

        n = n >> 16;

    }

    if (!(n & 0xFF)) {

        ret += 8;

        n = n >> 8;

    }

    if (!(n & 0xF)) {

        ret += 4;

        n = n >> 4;

    }

    if (!(n & 0x3)) {

        ret += 2;

        n = n >> 2;

    }

    if (!(n & 0x1)) {

        ret++;

        n = n >> 1;

    }

#if 0 /* This is not necessary as n is never 0 */

    if (!n)

        ret++;

#endif

    return ret;

}

pflash_t *pflash_cfi01_register(target_phys_addr_t base, ram_addr_t off,

                                BlockDriverState *bs, uint32_t sector_len,

                                int nb_blocs, int width,

                                uint16_t id0, uint16_t id1,

                                uint16_t id2, uint16_t id3)

{

    pflash_t *pfl;

    target_long total_len;

    total_len = sector_len * nb_blocs;

    /* XXX: to be fixed */

#if 0

    if (total_len != (8 * 1024 * 1024) && total_len != (16 * 1024 * 1024) &&

        total_len != (32 * 1024 * 1024) && total_len != (64 * 1024 * 1024))

        return NULL;

#endif

    pfl = qemu_mallocz(sizeof(pflash_t));

    if (pfl == NULL)

        return NULL;

    /* FIXME: This is broken if it spans multiple RAM regions.  */

    pfl->storage = host_ram_addr(off);

    pfl->fl_mem = cpu_register_io_memory(0,

                    pflash_read_ops, pflash_write_ops, pfl);

    pfl->off = off;