tsunami_flash.c

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/*
 * tsunami_flash.c
 *
 * flash chip on alpha ds10...
 */
#include <asm/io.h>
#include <asm/core_tsunami.h>
#include <linux/init.h>
#include <linux/mtd/map.h>
#include <linux/mtd/mtd.h>

#define FLASH_ENABLE_PORT 0x00C00001
#define FLASH_ENABLE_BYTE 0x01
#define FLASH_DISABLE_BYTE 0x00

#define MAX_TIG_FLASH_SIZE (12*1024*1024)
static inline map_word tsunami_flash_read8(struct map_info *map, unsigned long offset)
{
    map_word val;
    val.x[0] = tsunami_tig_readb(offset);
    return val;
}

static void tsunami_flash_write8(struct map_info *map, map_word value, unsigned long offset)
{
    tsunami_tig_writeb(value.x[0], offset);
}

static void tsunami_flash_copy_from(
    struct map_info *map, void *addr, unsigned long offset, ssize_t len)
{
    unsigned char *dest;
    dest = addr;
    while(len && (offset < MAX_TIG_FLASH_SIZE)) {
        *dest = tsunami_tig_readb(offset);
        offset++;
        dest++;
        len--;
    }
}

static void tsunami_flash_copy_to(
    struct map_info *map, unsigned long offset,
    const void *addr, ssize_t len)
{
    const unsigned char *src;
    src = addr;
    while(len && (offset < MAX_TIG_FLASH_SIZE)) {
        tsunami_tig_writeb(*src, offset);
        offset++;
        src++;
        len--;
    }
}

/*
 * Deliberately don't provide operations wider than 8 bits.  I don't
 * have then and it scares me to think how you could mess up if
 * you tried to use them.   Buswidth is correctly so I'm safe.
 */
static struct map_info tsunami_flash_map = {
    .name = "flash chip on the Tsunami TIG bus",
    .size = MAX_TIG_FLASH_SIZE,
    .phys = NO_XIP,
    .bankwidth = 1,
    .read = tsunami_flash_read8,
    .copy_from = tsunami_flash_copy_from,
    .write = tsunami_flash_write8,
    .copy_to = tsunami_flash_copy_to,
};

static struct mtd_info *tsunami_flash_mtd;

static void __exit  cleanup_tsunami_flash(void)
{
    struct mtd_info *mtd;
    mtd = tsunami_flash_mtd;
    if (mtd) {
        mtd_device_unregister(mtd);
        map_destroy(mtd);
    }
    tsunami_flash_mtd = 0;
}


static int __init init_tsunami_flash(void)
{
    static const char *rom_probe_types[] = { "cfi_probe", "jedec_probe", "map_rom", NULL };
    char **type;

    tsunami_tig_writeb(FLASH_ENABLE_BYTE, FLASH_ENABLE_PORT);

    tsunami_flash_mtd = 0;
    type = rom_probe_types;
    for(; !tsunami_flash_mtd && *type; type++) {
        tsunami_flash_mtd = do_map_probe(*type, &tsunami_flash_map);
    }
    if (tsunami_flash_mtd) {
        tsunami_flash_mtd->owner = THIS_MODULE;
        mtd_device_register(tsunami_flash_mtd, NULL, 0);
        return 0;
    }
    return -ENXIO;
}

module_init(init_tsunami_flash);
module_exit(cleanup_tsunami_flash);