pflash_cfi01.c.svn-base

我们自己开发的一个OSEK操作系统！不知道可不可以？

/*
 *  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;
    offset -= pfl->base;
    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\n",
            __func__, boff, pfl->cmd);

    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 pflash_write (pflash_t *pfl, target_ulong offset, uint32_t value,
                          int width)
{
    target_ulong boff;
    uint8_t *p;
    uint8_t cmd;

    /* WARNING: when the memory area is in ROMD mode, the offset is a
       ram offset, not a physical address */
    cmd = value;

    if (pfl->wcycle == 0)
        offset -= (target_ulong)(long)pfl->storage;
    else
        offset -= pfl->base;

    DPRINTF("%s: offset " TARGET_FMT_lx " %08x %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 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 0x20: /* Block erase */
        case 0x28:
            if (cmd == 0xd0) { /* confirm */
                pfl->wcycle = 1;
                pfl->status |= 0x80;
            } 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__, cmd);
            pfl->counter = cmd;
            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;