/* $NetBSD: athflash.c,v 1.12 2021/01/04 17:42:29 thorpej Exp $ */

/*
 * Copyright (c) 2006 Urbana-Champaign Independent Media Center.
 * Copyright (c) 2006 Garrett D'Amore.
 * All rights reserved.
 *
 * Portions of this code were written by Garrett D'Amore for the
 * Champaign-Urbana Community Wireless Network Project.
 *
 * 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.
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgements:
 *      This product includes software developed by the Urbana-Champaign
 *      Independent Media Center.
 *      This product includes software developed by Garrett D'Amore.
 * 4. Urbana-Champaign Independent Media Center's name and Garrett
 *    D'Amore's name may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE URBANA-CHAMPAIGN INDEPENDENT
 * MEDIA CENTER AND GARRETT D'AMORE ``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 URBANA-CHAMPAIGN INDEPENDENT
 * MEDIA CENTER OR GARRETT D'AMORE 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.
 */
/*
 * 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
 *
 * XXX This primitive flash driver does *not* support boot sectored devices,
 * XXX and only supports a fairly limited set of devices, that we are likely to
 * XXX to find in an AP30.
 * XXX
 * XXX We also are only supporting flash widths of 16 _for the moment_, and
 * XXX we are only supporting flash devices that use the AMD command sets.
 * XXX All this should be reviewed and improved to be much more generic.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: athflash.c,v 1.12 2021/01/04 17:42:29 thorpej 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 <sys/bus.h>

#include <mips/atheros/include/arbusvar.h>

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

struct flash_softc {
        bus_space_tag_t         sc_iot;
        bus_space_handle_t      sc_ioh;
        size_t                  sc_size;
        size_t                  sc_sector_size;
        int                     sc_status;
        u_int8_t                *sc_buf;
};

#define FLASH_ST_BUSY   0x1

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

static int is_block_same(struct flash_softc *, bus_size_t, const void *);
static int toggle_bit_wait(struct flash_softc *, bus_size_t, int, int, int);

static int flash_sector_erase(struct flash_softc *, bus_size_t);
static int flash_sector_write(struct flash_softc *, bus_size_t);

extern struct cfdriver athflash_cd;

CFATTACH_DECL_NEW(athflash, 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 athflash_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 struct {
        uint16_t                vendor_id;
        uint16_t                device_id;
        const char              *name;
        int                     sector_size;
        int                     flash_size;
} flash_ids[] = {
        { 0x00bf, 0x2780, "SST 39VF400", 0x01000, 0x080000 },   /* 512KB */
        { 0x00bf, 0x2782, "SST 39VF160", 0x01000, 0x200000 },   /* 2MB */
        { 0xffff, 0xffff, NULL, 0, 0 }                          /* end list */
};

static int
flash_probe(device_t parent, cfdata_t cf, void *aux)
{
        struct arbus_attach_args        *aa = aux;
        bus_space_handle_t              ioh;
        int                             rv = 0, i;
        uint16_t                        venid, devid;

        if (strcmp(aa->aa_name, cf->cf_name) != 0)
                return 0;

        DPRINTF(("trying to map address %x\n", (unsigned)aa->aa_addr));
        if (bus_space_map(aa->aa_bst, aa->aa_addr, aa->aa_size, 0, &ioh))
                return 0;

        /* issue JEDEC query */
        DPRINTF(("issuing JEDEC query\n"));
        bus_space_write_2(aa->aa_bst, ioh, (0x5555 << 1), 0xAAAA);
        bus_space_write_2(aa->aa_bst, ioh, (0x2AAA << 1), 0x5555);
        bus_space_write_2(aa->aa_bst, ioh, (0x5555 << 1), 0x9090);

        delay(100);
        venid = bus_space_read_2(aa->aa_bst, ioh, 0);
        devid = bus_space_read_2(aa->aa_bst, ioh, 2);

        /* issue software exit */
        bus_space_write_2(aa->aa_bst, ioh, 0x0, 0xF0F0);

        for (i = 0; flash_ids[i].name != NULL; i++) {
                if ((venid == flash_ids[i].vendor_id) &&
                    (devid == flash_ids[i].device_id)) {
                        rv = 1;
                        break;
                }
        }

        bus_space_unmap(aa->aa_bst, ioh, aa->aa_size);
        return rv;
}

static void
flash_attach(device_t parent, device_t self, void *aux)
{
        char nbuf[32];
        struct flash_softc              *sc = device_private(self);
        struct arbus_attach_args        *aa = aux;
        int                             i;
        bus_space_tag_t                 iot = aa->aa_bst;
        bus_space_handle_t              ioh;
        uint16_t                        venid, devid;

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

        /* issue JEDEC query */
        bus_space_write_2(aa->aa_bst, ioh, (0x5555 << 1), 0xAAAA);
        bus_space_write_2(aa->aa_bst, ioh, (0x2AAA << 1), 0x5555);
        bus_space_write_2(aa->aa_bst, ioh, (0x5555 << 1), 0x9090);

        delay(100);
        venid = bus_space_read_2(aa->aa_bst, ioh, 0);
        devid = bus_space_read_2(aa->aa_bst, ioh, 2);

        /* issue software exit */
        bus_space_write_2(aa->aa_bst, ioh, 0x0, 0xF0F0);

        for (i = 0; flash_ids[i].name != NULL; i++) {
                if ((venid == flash_ids[i].vendor_id) &&
                    (devid == flash_ids[i].device_id)) {
                        break;
                }
        }

        KASSERT(flash_ids[i].name != NULL);
        printf(": %s", flash_ids[i].name);
        if (humanize_number(nbuf, sizeof(nbuf), flash_ids[i].flash_size, "B",
            1024) > 0)
                printf(" (%s)", nbuf);

        /*
         * determine size of the largest block
         */
        sc->sc_size = flash_ids[i].flash_size;
        sc->sc_sector_size = flash_ids[i].sector_size;

        sc->sc_buf = kmem_alloc(sc->sc_sector_size, KM_SLEEP);

        printf("\n");
}

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

        sc = device_lookup_private(&athflash_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(&athflash_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(&athflash_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_sector_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(&athflash_cd, minor(dev));

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

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

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

static int
toggle_bit_wait(struct flash_softc *sc, bus_size_t offset,
    int typtmo, int maxtmo, int spin)
{
        bus_space_tag_t         iot = sc->sc_iot;
        bus_space_handle_t      ioh = sc->sc_ioh;
        uint8_t                 d1, d2;

        while (maxtmo > 0) {

                if (spin) {
                        DELAY(typtmo);
                } else {
                        tsleep(sc, PRIBIO, "blockerase",
                            (typtmo / hz) + 1);
                }

                d1 = bus_space_read_1(iot, ioh, offset);
                d2 = bus_space_read_2(iot, ioh, offset);

                /* watch for the toggle bit to stop toggling */
                if ((d1 & 0x40) == (d2 & 0x40)) {
                        return 0;
                }

                maxtmo -= typtmo;
        }
        return (ETIMEDOUT);
}

static int
flash_sector_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;

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

        bus_space_write_2(iot, ioh, (0x5555 << 1), 0xAAAA);
        bus_space_write_2(iot, ioh, (0x2AAA << 1), 0x5555);
        bus_space_write_2(iot, ioh, (0x5555 << 1), 0x8080);
        bus_space_write_2(iot, ioh, (0x5555 << 1), 0xAAAA);
        bus_space_write_2(iot, ioh, (0x2AAA << 1), 0x5555);

        bus_space_write_2(iot, ioh, offset, 0x3030);

        /*
         * NB: with CFI, we could get more meaningful timeout data for
         * now we just assign reasonable values - 10 msec typical, and
         * up to 60 secs to erase the whole sector.
         */

        return toggle_bit_wait(sc, offset, 10000, 60000000, 0);
}

static int
flash_sector_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;
        bus_size_t              fence;
        const u_int16_t         *p;

        p = (u_int16_t *) sc->sc_buf;
        fence = offset + sc->sc_sector_size;
        do {
                bus_space_write_2(iot, ioh, (0x5555 << 1), 0xAAAA);
                bus_space_write_2(iot, ioh, (0x2AAA << 1), 0x5555);
                bus_space_write_2(iot, ioh, (0xAAAA << 1), 0xA0A0);

                bus_space_write_2(iot, ioh, offset, *p);

                /* wait up to 1 msec, in 10 usec increments, no sleeping */
                if (toggle_bit_wait(sc, offset, 10, 1000, 1) != 0)
                        return ETIMEDOUT;
                p++;
                offset += 2;
        } while (offset < fence);

        return 0;
}