/* $NetBSD: flash_vrip.c,v 1.15 2023/09/12 19:32:00 andvar Exp $ */

/*
 * Copyright (c) 2002 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Naoto Shimazaki of YOKOGAWA Electric Corporation.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Flash Memory Driver
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: flash_vrip.c,v 1.15 2023/09/12 19:32:00 andvar Exp $");

#include <sys/param.h>
#include <sys/conf.h>
#include <sys/device.h>
#include <sys/kernel.h>
#include <sys/kmem.h>
#include <sys/proc.h>
#include <sys/systm.h>

#include <machine/bus.h>

#include <hpcmips/vr/vripif.h>
#include <hpcmips/vr/cfireg.h>
#include <hpcmips/vr/flashreg.h>
#include <hpcmips/vr/flashvar.h>

#ifdef FLASH_DEBUG
int     flash_debug = 0;
#define DPRINTF(x)      if (flash_debug) printf x
#else
#define DPRINTF(x)
#endif

static int flash_probe(device_t, cfdata_t, void *);
static void flash_attach(device_t, device_t, void *);

const static struct flashops * find_command_set(u_int8_t cmdset0,
                                                u_int8_t cmdset1);
static int i28f128_probe(bus_space_tag_t, bus_space_handle_t);
static int mbm29160_probe(bus_space_tag_t, bus_space_handle_t);
static int is_block_same(struct flash_softc *, bus_size_t, const void *);
static int probe_cfi(bus_space_tag_t iot, bus_space_handle_t ioh);

static int intel_erase(struct flash_softc *, bus_size_t);
static int intel_write(struct flash_softc *, bus_size_t);
static int amd_erase(struct flash_softc *, bus_size_t);
static int amd_write(struct flash_softc *, bus_size_t);

extern struct cfdriver vrflash_cd;

CFATTACH_DECL_NEW(flash_vrip, sizeof(struct flash_softc),
              flash_probe, flash_attach, NULL, NULL);

dev_type_open(flashopen);
dev_type_close(flashclose);
dev_type_read(flashread);
dev_type_write(flashwrite);

const struct cdevsw vrflash_cdevsw = {
        .d_open = flashopen,
        .d_close = flashclose,
        .d_read = flashread,
        .d_write = flashwrite,
        .d_ioctl = noioctl,
        .d_stop = nostop,
        .d_tty = notty,
        .d_poll = nopoll,
        .d_mmap = nommap,
        .d_kqfilter = nokqfilter,
        .d_discard = nodiscard,
        .d_flag = 0
};

static const struct flash_command_set {
        u_int8_t        fc_set0;
        u_int8_t        fc_set1;
        struct flashops fc_ops;
} flash_cmd[] = {
        {
                .fc_set0        = CFI_COMMSET_INTEL0,
                .fc_set1        = CFI_COMMSET_INTEL1,
                .fc_ops         = {
                        .fo_name        = "Intel",
                        .fo_erase       = intel_erase,
                        .fo_write       = intel_write,
                }
        },
        {
                .fc_set0        = CFI_COMMSET_AMDFJITU0,
                .fc_set1        = CFI_COMMSET_AMDFJITU1,
                .fc_ops         = {
                        .fo_name        = "AMD/Fujitsu",
                        .fo_erase       = amd_erase,
                        .fo_write       = amd_write,
                }
        },
        {
                .fc_set0        = 0,
                .fc_set1        = 0,
                .fc_ops         = {
                        .fo_name        = NULL,
                        .fo_erase       = NULL,
                        .fo_write       = NULL,
                }
        }
};


const static struct flashops *
find_command_set(u_int8_t cmdset0, u_int8_t cmdset1)
{
        const struct flash_command_set  *fc;

        for (fc = flash_cmd; fc->fc_ops.fo_name; fc++) {
                if (cmdset0 == fc->fc_set0 && cmdset1 == fc->fc_set1)
                        return &fc->fc_ops;
        }
        return NULL;
}

static int
probe_cfi(bus_space_tag_t iot, bus_space_handle_t ioh)
{
        const u_int8_t  *idstr = CFI_QUERY_ID_STR;
        int             i;
        u_int8_t        cmdset0;
        u_int8_t        cmdset1;

        /* start Common Flash Interface Query */
        bus_space_write_2(iot, ioh, CFI_QUERY_OFFSET, CFI_READ_CFI_QUERY);

        /* read CFI Query ID string */
        i = CFI_QUERY_ID_STR_REG << 1;
        do {
                if (bus_space_read_2(iot, ioh, i) != *idstr) {
                        bus_space_write_2(iot, ioh, 0, FLASH_RESET);
                        return 1;
                }
                i += 2;
                idstr++;
        } while (*idstr);

        cmdset0 = bus_space_read_2(iot, ioh, CFI_PRIM_COMM_REG0 << 1);
        cmdset1 = bus_space_read_2(iot, ioh, CFI_PRIM_COMM_REG1 << 1);

        /* switch flash to read mode */
        bus_space_write_2(iot, ioh, 0, FLASH_RESET);

        if (!find_command_set(cmdset0, cmdset1))
                return 1;

        return 0;
}

static int
flash_probe(device_t parent, cfdata_t match, void *aux)
{
        struct vrip_attach_args *va = aux;
        bus_space_handle_t      ioh;

        if (bus_space_map(va->va_iot, va->va_addr, va->va_size, 0, &ioh))
                return 0;
        if (!probe_cfi(va->va_iot, ioh)) {
                DPRINTF(("CFI ID str and command set recognized\n"));
                goto detect;
        }
        if (!i28f128_probe(va->va_iot, ioh)) {
                DPRINTF(("28F128 detected\n"));
                goto detect;
        }
        if (!mbm29160_probe(va->va_iot, ioh)) {
                DPRINTF(("29LV160 detected\n"));
                goto detect;
        }
        return 0;

detect:
        bus_space_unmap(va->va_iot, ioh, va->va_size);
        return 1;
}

static void
flash_attach(device_t parent, device_t self, void *aux)
{
        struct flash_softc      *sc = device_private(self);
        struct vrip_attach_args *va = aux;
        int                     i;
        int                     fence;
        bus_space_tag_t         iot = va->va_iot;
        bus_space_handle_t      ioh;
        size_t                  block_size;

        if (bus_space_map(iot, va->va_addr, va->va_size, 0, &ioh)) {
                printf(": can't map i/o space\n");
                return;
        }
        
        sc->sc_iot = iot;
        sc->sc_ioh = ioh;
        sc->sc_size = va->va_size;
        sc->sc_status = 0;

        /*
         * Read entire CFI structure
         */
        bus_space_write_2(iot, ioh, CFI_QUERY_OFFSET, CFI_READ_CFI_QUERY);
        for (i = 0; i < CFI_TOTAL_SIZE; i++) {
                sc->sc_cfi_raw[i] = bus_space_read_2(iot, ioh, i << 1);
        }
        bus_space_write_2(iot, ioh, 0, FLASH_RESET);

        sc->sc_ops = find_command_set(sc->sc_cfi_raw[CFI_PRIM_COMM_REG0],
                                      sc->sc_cfi_raw[CFI_PRIM_COMM_REG1]);
        if (sc->sc_ops) {
                printf(": using %s command set", sc->sc_ops->fo_name);
        } else {
                printf("opps sc->sc_ops is NULL\n");
        }

        /*
         * determine size of the largest block
         */
        sc->sc_block_size = 0;
        i = CFI_EBLK1_INFO_REG;
        fence = sc->sc_cfi_raw[CFI_NUM_ERASE_BLK_REG] * CFI_EBLK_INFO_SIZE
                + i;
        for (; i < fence; i += CFI_EBLK_INFO_SIZE) {
                if (sc->sc_cfi_raw[i + CFI_EBLK_INFO_NSECT0] == 0
                    && sc->sc_cfi_raw[i + CFI_EBLK_INFO_NSECT1] == 0)
                        continue;
                block_size
                        = (sc->sc_cfi_raw[i + CFI_EBLK_INFO_SECSIZE0] << 8)
                        + (sc->sc_cfi_raw[i + CFI_EBLK_INFO_SECSIZE1] << 16);
                if (sc->sc_block_size < block_size)
                        sc->sc_block_size = block_size;
        }
        
        sc->sc_buf = kmem_alloc(sc->sc_block_size, KM_SLEEP);

        sc->sc_write_buffer_size
                = 1 << (sc->sc_cfi_raw[CFI_MAX_WBUF_SIZE_REG0]
                        + (sc->sc_cfi_raw[CFI_MAX_WBUF_SIZE_REG1] << 8));
        sc->sc_typ_word_prog_timo
                = 1 << sc->sc_cfi_raw[CFI_TYP_WORD_PROG_REG];
        sc->sc_max_word_prog_timo
                = 1 << sc->sc_cfi_raw[CFI_MAX_WORD_PROG_REG];
        sc->sc_typ_buffer_write_timo
                = 1 << sc->sc_cfi_raw[CFI_TYP_BUF_WRITE_REG];
        sc->sc_max_buffer_write_timo
                = 1 << sc->sc_cfi_raw[CFI_MAX_BUF_WRITE_REG];
        sc->sc_typ_block_erase_timo
                = 1 << sc->sc_cfi_raw[CFI_TYP_BLOCK_ERASE_REG];
        sc->sc_max_block_erase_timo
                = 1 << sc->sc_cfi_raw[CFI_MAX_BLOCK_ERASE_REG];

        printf("\n");

#ifdef FLASH_DEBUG
        printf("read_cfi: extract cfi\n");
        printf("max block size: %dbyte\n", sc->sc_block_size);
        printf("write buffer size: %dbyte\n", sc->sc_write_buffer_size);
        printf("typical word program timeout: %dusec\n",
               sc->sc_typ_word_prog_timo);
        printf("maximam word program timeout: %dusec (%d time of typ)\n",
               sc->sc_typ_word_prog_timo * sc->sc_max_word_prog_timo,
               sc->sc_max_word_prog_timo);
        printf("typical buffer write timeout: %dusec\n",
               sc->sc_typ_buffer_write_timo);
        printf("maximam buffer write timeout: %dusec (%d time of typ)\n",
               sc->sc_typ_buffer_write_timo * sc->sc_max_buffer_write_timo,
               sc->sc_max_buffer_write_timo);
        printf("typical block erase timeout: %dmsec\n",
               sc->sc_typ_block_erase_timo);
        printf("maximam block erase timeout: %dmsec (%d time of typ)\n",
               sc->sc_typ_block_erase_timo * sc->sc_max_block_erase_timo,
               sc->sc_max_block_erase_timo);

        printf("read_cfi: dump cfi\n");
        for (i = 0; i < CFI_TOTAL_SIZE;) {
                int     j;
                for (j = 0; j < 16; j++) {
                        printf("%02x ", sc->sc_cfi_raw[i++]);
                }
                printf("\n");
        }
#endif
}

int
flashopen(dev_t dev, int flag, int mode, struct lwp *l)
{
        struct flash_softc      *sc;

        sc = device_lookup_private(&vrflash_cd, minor(dev));
        if (sc == NULL)
                return ENXIO;
        if (sc->sc_status & FLASH_ST_BUSY)
                return EBUSY;
        sc->sc_status |= FLASH_ST_BUSY;
        return 0;
}

int
flashclose(dev_t dev, int flag, int mode, struct lwp *l)
{
        struct flash_softc      *sc;

        sc = device_lookup_private(&vrflash_cd, minor(dev));
        sc->sc_status &= ~FLASH_ST_BUSY;
        return 0;
}

int
flashread(dev_t dev, struct uio *uio, int flag)
{
        struct flash_softc      *sc;
        bus_space_tag_t         iot;
        bus_space_handle_t      ioh;
        bus_size_t              off;
        int                     total;
        int                     count;
        int                     error;

        sc = device_lookup_private(&vrflash_cd, minor(dev));
        iot = sc->sc_iot;
        ioh = sc->sc_ioh;

        off = uio->uio_offset;
        total = uimin(sc->sc_size - off, uio->uio_resid);

        while (total > 0) {
                count = uimin(sc->sc_block_size, uio->uio_resid);
                bus_space_read_region_1(iot, ioh, off, sc->sc_buf, count);
                if ((error = uiomove(sc->sc_buf, count, uio)) != 0)
                        return error;
                off += count;
                total -= count;
        }
        return 0;
}


int
flashwrite(dev_t dev, struct uio *uio, int flag)
{
        struct flash_softc      *sc;
        bus_size_t              off;
        int                     stat;
        int                     error;

        sc = device_lookup_private(&vrflash_cd, minor(dev));

        if (sc->sc_size < uio->uio_offset + uio->uio_resid)
                return ENOSPC;
        if (uio->uio_offset % sc->sc_block_size)
                return EINVAL;
        if (uio->uio_resid % sc->sc_block_size)
                return EINVAL;

        for (off = uio->uio_offset;
             uio->uio_resid > 0;
             off += sc->sc_block_size) {
                if ((error = uiomove(sc->sc_buf, sc->sc_block_size, uio)) != 0)
                        return error;
                if (is_block_same(sc, off, sc->sc_buf))
                        continue;
                if ((stat = flash_block_erase(sc, off)) != 0) {
                        printf("block erase failed status = 0x%x\n", stat);
                        return EIO;
                }
                if ((stat = flash_block_write(sc, off)) != 0) {
                        printf("block write failed status = 0x%x\n", stat);
                        return EIO;
                }
        }
        return 0;
}

/*
 * XXX
 * this function is too much specific for the device.
 */
static int
i28f128_probe(bus_space_tag_t iot, bus_space_handle_t ioh)
{
        static const u_int8_t   vendor_code[] = {
                0x89,   /* manufacturer code:   intel */
                0x18,   /* device code:         28F128 */
        };

        static const u_int8_t   idstr[] = {
                'Q', 'R', 'Y',
                0x01, 0x00,
                0x31, 0x00,
                0xff
        };

        int     i;

        /* start Common Flash Interface Query */
        bus_space_write_2(iot, ioh, 0, CFI_READ_CFI_QUERY);
        /* read CFI Query ID string */
        for (i = 0; idstr[i] != 0xff; i++) {
                if (bus_space_read_2(iot, ioh, (0x10 + i) << 1) != idstr[i])
                        return 1;
        }

        /* read manufacturer code and device code */
        if (bus_space_read_2(iot, ioh, 0x00) != vendor_code[0])
                return 1;
        if (bus_space_read_2(iot, ioh, 0x02) != vendor_code[1])
                return 1;
        
        bus_space_write_2(iot, ioh, 0, I28F128_RESET);
        return 0;
}

/*
 * XXX
 * this function is too much specific for the device.
 */
static int
mbm29160_probe(bus_space_tag_t iot, bus_space_handle_t ioh)
{
        static const u_int16_t  vendor_code[] = {
                0x0004, /* manufacturer code:   intel */
                0x2249, /* device code:         29LV160BE */
        };

        static const u_int8_t   idstr[] = {
                'Q', 'R', 'Y',
                0x02, 0x00,
                0x40, 0x00,
                0xff
        };

        int     i;

        /* start Common Flash Interface Query */
        bus_space_write_2(iot, ioh, 0xaa, CFI_READ_CFI_QUERY);
        /* read CFI Query ID string */
        for (i = 0; idstr[i] != 0xff; i++) {
                if (bus_space_read_2(iot, ioh, (0x10 + i) << 1) != idstr[i])
                        return 1;
        }

        bus_space_write_2(iot, ioh, 0, 0xff);

        /* read manufacturer code and device code */
        bus_space_write_2(iot, ioh, 0x555 << 1, 0xaa);
        bus_space_write_2(iot, ioh, 0x2aa << 1, 0x55);
        bus_space_write_2(iot, ioh, 0x555 << 1, 0x90);
        if (bus_space_read_2(iot, ioh, 0x00) != vendor_code[0])
                return 1;
        if (bus_space_read_2(iot, ioh, 0x02) != vendor_code[1])
                return 1;
        
        bus_space_write_2(iot, ioh, 0, 0xff);
        return 0;
}

static int
is_block_same(struct flash_softc *sc, bus_size_t offset, const void *bufp)
{
        bus_space_tag_t         iot = sc->sc_iot;
        bus_space_handle_t      ioh = sc->sc_ioh;
        const u_int8_t          *p = bufp;
        int                     count = sc->sc_block_size;

        while (count-- > 0) {
                if (bus_space_read_1(iot, ioh, offset++) != *p++)
                        return 0;
        }
        return 1;
}

static int
intel_erase(struct flash_softc *sc, bus_size_t offset)
{
        bus_space_tag_t         iot = sc->sc_iot;
        bus_space_handle_t      ioh = sc->sc_ioh;
        int                     status;
        int                     i;

        bus_space_write_2(iot, ioh, offset, I28F128_BLK_ERASE_1ST);
        bus_space_write_2(iot, ioh, offset, I28F128_BLK_ERASE_2ND);

        status = 0;
        for (i = sc->sc_max_block_erase_timo; i > 0; i--) {
                tsleep(sc, PRIBIO, "blockerase",
                       1 + (sc->sc_typ_block_erase_timo * hz) / 1000);
                if ((status = bus_space_read_2(iot, ioh, offset))
                    & I28F128_S_READY)
                        break;
        }
        if (i == 0) 
                status |= FLASH_TIMEOUT; 

        bus_space_write_2(iot, ioh, offset, I28F128_CLEAR_STATUS);
        bus_space_write_2(iot, ioh, offset, I28F128_RESET);

        return status & (FLASH_TIMEOUT
                         | I28F128_S_ERASE_SUSPEND
                         | I28F128_S_COMSEQ_ERROR
                         | I28F128_S_ERASE_ERROR
                         | I28F128_S_BLOCK_LOCKED);
}

static int
intel_write(struct flash_softc *sc, bus_size_t offset)
{
        bus_space_tag_t         iot = sc->sc_iot;
        bus_space_handle_t      ioh = sc->sc_ioh;
        int                     wbuf_size;
        int                     timo;
        int                     status;
        bus_size_t              fence;
        int                     i;
        const u_int16_t         *p;

        /* wbuf_size = size in u_int16_t */
        wbuf_size = sc->sc_write_buffer_size >> 1;

        p = (u_int16_t *) sc->sc_buf;
        fence = offset + sc->sc_block_size;
        do {
                status = 0;
                for (timo = sc->sc_max_buffer_write_timo; timo > 0; timo--) {
                        bus_space_write_2(iot, ioh, offset,
                                          I28F128_WRITE_BUFFER);
                        status = bus_space_read_2(iot, ioh, offset);
                        if (status & I28F128_XS_BUF_AVAIL)
                                break;
                        DELAY(sc->sc_typ_buffer_write_timo);
                }
                if (timo == 0) {
                        status |= FLASH_TIMEOUT;
                        goto errout;
                }

                bus_space_write_2(iot, ioh, offset, wbuf_size - 1);

                for (i = wbuf_size; i > 0; i--, p++, offset += 2)
                        bus_space_write_2(iot, ioh, offset, *p);

                bus_space_write_2(iot, ioh, offset, I28F128_WBUF_CONFIRM);

                do {
                        bus_space_write_2(iot, ioh, offset,
                                          I28F128_READ_STATUS);
                        status = bus_space_read_2(iot, ioh, offset);
                } while (!(status & I28F128_S_READY));

        } while (offset < fence);

        bus_space_write_2(iot, ioh, offset, I28F128_CLEAR_STATUS);
        bus_space_write_2(iot, ioh, offset, I28F128_RESET);

        return 0;

errout:
        bus_space_write_2(iot, ioh, offset, I28F128_CLEAR_STATUS);
        bus_space_write_2(iot, ioh, offset, I28F128_RESET);

        status &= (FLASH_TIMEOUT
                   | I28F128_S_PROG_ERROR
                   | I28F128_S_COMSEQ_ERROR
                   | I28F128_S_LOW_VOLTAGE
                   | I28F128_S_PROG_SUSPEND
                   | I28F128_S_BLOCK_LOCKED);
        return status;
}

static int
amd_erase_sector(struct flash_softc *sc, bus_size_t offset)
{
        bus_space_tag_t         iot = sc->sc_iot;
        bus_space_handle_t      ioh = sc->sc_ioh;
        int                     i;

        DPRINTF(("amd_erase_sector offset = %08lx\n", offset));

        bus_space_write_2(iot, ioh,
                          MBM29LV160_COMM_ADDR0, MBM29LV160_COMM_CMD0);
        bus_space_write_2(iot, ioh,
                          MBM29LV160_COMM_ADDR1, MBM29LV160_COMM_CMD1);
        bus_space_write_2(iot, ioh,
                          MBM29LV160_COMM_ADDR2, MBM29LV160_ESECT_CMD2);
        bus_space_write_2(iot, ioh,
                          MBM29LV160_COMM_ADDR3, MBM29LV160_ESECT_CMD3);
        bus_space_write_2(iot, ioh,
                          MBM29LV160_COMM_ADDR4, MBM29LV160_ESECT_CMD4);
        bus_space_write_2(iot, ioh, offset, MBM29LV160_ESECT_CMD5);

        for (i = sc->sc_max_block_erase_timo; i > 0; i--) {
                tsleep(sc, PRIBIO, "blockerase",
                       1 + (sc->sc_typ_block_erase_timo * hz) / 1000);
                if (bus_space_read_2(iot, ioh, offset) == 0xffff)
                        return 0;
        }

        return FLASH_TIMEOUT;
}

static int
amd_erase(struct flash_softc *sc, bus_size_t offset)
{
        static const struct mbm29lv_subsect {
                u_int16_t       devcode;
                u_int32_t       subsect_mask;
                u_int32_t       subsect_addr;
        } subsect[] = {
                {
                        MBM29LV160TE_DEVCODE,
                        MBM29LV160_SUBSECT_MASK,
                        MBM29LV160TE_SUBSECT_ADDR
                },
                {
                        MBM29LV160BE_DEVCODE,
                        MBM29LV160_SUBSECT_MASK,
                        MBM29LV160BE_SUBSECT_ADDR
                },
                { 0, 0, 0 }
        };

        bus_space_tag_t                 iot = sc->sc_iot;
        bus_space_handle_t              ioh = sc->sc_ioh;
        u_int16_t                       devcode;
        const struct mbm29lv_subsect    *ss;
        bus_size_t                      fence;
        int                             step;
        int                             status;

        bus_space_write_2(iot, ioh,
                          MBM29LV160_COMM_ADDR0, MBM29LV160_COMM_CMD0);
        bus_space_write_2(iot, ioh,
                          MBM29LV160_COMM_ADDR1, MBM29LV160_COMM_CMD1);
        bus_space_write_2(iot, ioh,
                          MBM29LV160_COMM_ADDR2, MBM29LV160_SIGN_CMD2);
        devcode = bus_space_read_2(iot, ioh, MBM29LV160_DEVCODE_REG);

        for (ss = subsect; ss->devcode; ss++) {
                if (ss->devcode == devcode)
                        break;
        }
        if (ss->devcode == 0) {
                printf("flash: amd_erase(): unknown device code %04x\n",
                       devcode);
                return -1;
        }

        DPRINTF(("flash: amd_erase(): devcode = %04x subsect = %08x\n",
                 devcode, ss->subsect_addr));

        fence = offset + sc->sc_block_size;
        step = (offset & ss->subsect_mask) == ss->subsect_addr
                ? MBM29LV160_SUBSECT_SIZE : MBM29LV160_SECT_SIZE;
        do {
                if ((status = amd_erase_sector(sc, offset)) != 0)
                        return status;
                offset += step;
        } while (offset < fence);

        return 0;
}

static int
amd_write(struct flash_softc *sc, bus_size_t offset)
{
        bus_space_tag_t         iot = sc->sc_iot;
        bus_space_handle_t      ioh = sc->sc_ioh;
        int                     timo;
        bus_size_t              fence;
        const u_int16_t         *p;

        p = (u_int16_t *) sc->sc_buf;
        fence = offset + sc->sc_block_size;
        do {
                bus_space_write_2(iot, ioh,
                                  MBM29LV160_COMM_ADDR0,
                                  MBM29LV160_COMM_CMD0);
                bus_space_write_2(iot, ioh,
                                  MBM29LV160_COMM_ADDR1,
                                  MBM29LV160_COMM_CMD1);
                bus_space_write_2(iot, ioh,
                                  MBM29LV160_COMM_ADDR2,
                                  MBM29LV160_PROG_CMD2);
                bus_space_write_2(iot, ioh, offset, *p);

                for (timo = sc->sc_max_word_prog_timo; timo > 0; timo--) {
                        if (bus_space_read_2(iot, ioh, offset) == *p)
                                break;
                        DELAY(sc->sc_typ_word_prog_timo);
                }
                if (timo == 0)
                        return FLASH_TIMEOUT;

                p++;
                offset += 2;
        } while (offset < fence);

        return 0;
}