/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2011-2012 Ian Lepore All rights reserved.
 * Copyright (c) 2012 Marius Strobl <marius@FreeBSD.org> All rights reserved.
 * Copyright (c) 2006 M. Warner Losh <imp@FreeBSD.org>

 * 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 AUTHOR ``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 AUTHOR 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.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bio.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/endian.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/lock.h>
#include <sys/mbuf.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <geom/geom_disk.h>

#include <dev/spibus/spi.h>
#include "spibus_if.h"

#include "opt_platform.h"

#ifdef FDT
#include <dev/fdt/fdt_common.h>
#include <dev/ofw/ofw_bus_subr.h>
#include <dev/ofw/openfirm.h>

static struct ofw_compat_data compat_data[] = {
        { "atmel,at45",         1 },
        { "atmel,dataflash",    1 },
        { NULL,                 0 },
};
#endif

/* This is the information returned by the MANUFACTURER_ID command. */
struct at45d_mfg_info {
        uint32_t        jedec_id; /* Mfg ID, DevId1, DevId2, ExtLen */
        uint16_t        ext_id;   /* ExtId1, ExtId2 */
};

/*
 * This is an entry in our table of metadata describing the chips.  We match on
 * both jedec id and extended id info returned by the MANUFACTURER_ID command.
 */
struct at45d_flash_ident
{
        const char      *name;
        uint32_t        jedec;
        uint16_t        extid;
        uint16_t        extmask;
        uint16_t        pagecount;
        uint16_t        pageoffset;
        uint16_t        pagesize;
        uint16_t        pagesize2n;
};

struct at45d_softc
{
        struct bio_queue_head   bio_queue;
        struct mtx              sc_mtx;
        struct disk             *disk;
        struct proc             *p;
        device_t                dev;
        u_int                   taskstate;
        uint16_t                pagecount;
        uint16_t                pageoffset;
        uint16_t                pagesize;
        void                    *dummybuf;
};

#define TSTATE_STOPPED  0
#define TSTATE_STOPPING 1
#define TSTATE_RUNNING  2

#define AT45D_LOCK(_sc)                 mtx_lock(&(_sc)->sc_mtx)
#define AT45D_UNLOCK(_sc)               mtx_unlock(&(_sc)->sc_mtx)
#define AT45D_LOCK_INIT(_sc) \
        mtx_init(&_sc->sc_mtx, device_get_nameunit(_sc->dev), \
            "at45d", MTX_DEF)
#define AT45D_LOCK_DESTROY(_sc)         mtx_destroy(&_sc->sc_mtx);
#define AT45D_ASSERT_LOCKED(_sc)        mtx_assert(&_sc->sc_mtx, MA_OWNED);
#define AT45D_ASSERT_UNLOCKED(_sc)      mtx_assert(&_sc->sc_mtx, MA_NOTOWNED);

/* bus entry points */
static device_attach_t at45d_attach;
static device_detach_t at45d_detach;
static device_probe_t at45d_probe;

/* disk routines */
static int at45d_close(struct disk *dp);
static int at45d_open(struct disk *dp);
static int at45d_getattr(struct bio *bp);
static void at45d_strategy(struct bio *bp);
static void at45d_task(void *arg);

/* helper routines */
static void at45d_delayed_attach(void *xsc);
static int at45d_get_mfg_info(device_t dev, struct at45d_mfg_info *resp);
static int at45d_get_status(device_t dev, uint8_t *status);
static int at45d_wait_ready(device_t dev, uint8_t *status);

#define PAGE_TO_BUFFER_TRANSFER         0x53
#define PAGE_TO_BUFFER_COMPARE          0x60
#define PROGRAM_THROUGH_BUFFER          0x82
#define MANUFACTURER_ID                 0x9f
#define STATUS_REGISTER_READ            0xd7
#define CONTINUOUS_ARRAY_READ           0xe8

#define STATUS_READY                    (1u << 7)
#define STATUS_CMPFAIL                  (1u << 6)
#define STATUS_PAGE2N                   (1u << 0)

/*
 * Metadata for supported chips.
 *
 * The jedec id in this table includes the extended id length byte.  A match is
 * based on both jedec id and extended id matching.  The chip's extended id (not
 * present in most chips) is ANDed with ExtMask and the result is compared to
 * ExtId.  If a chip only returns 1 ext id byte it will be in the upper 8 bits
 * of ExtId in this table.
 *
 * A sectorsize2n != 0 is used to indicate that a device optionally supports
 * 2^N byte pages.  If support for the latter is enabled, the sector offset
 * has to be reduced by one.
 */
static const struct at45d_flash_ident at45d_flash_devices[] = {
        /* Part Name    Jedec ID    ExtId   ExtMask PgCnt Offs PgSz PgSz2n */
        { "AT45DB011B", 0x1f220000, 0x0000, 0x0000,   512,  9,  264,  256 },
        { "AT45DB021B", 0x1f230000, 0x0000, 0x0000,  1024,  9,  264,  256 },
        { "AT45DB041x", 0x1f240000, 0x0000, 0x0000,  2028,  9,  264,  256 },
        { "AT45DB081B", 0x1f250000, 0x0000, 0x0000,  4096,  9,  264,  256 },
        { "AT45DB161x", 0x1f260000, 0x0000, 0x0000,  4096, 10,  528,  512 },
        { "AT45DB321x", 0x1f270000, 0x0000, 0x0000,  8192, 10,  528,    0 },
        { "AT45DB321x", 0x1f270100, 0x0000, 0x0000,  8192, 10,  528,  512 },
        { "AT45DB641E", 0x1f280001, 0x0000, 0xff00, 32768,  9,  264,  256 },
        { "AT45DB642x", 0x1f280000, 0x0000, 0x0000,  8192, 11, 1056, 1024 },
};

static int
at45d_get_status(device_t dev, uint8_t *status)
{
        uint8_t rxBuf[8], txBuf[8];
        struct spi_command cmd;
        int err;

        memset(&cmd, 0, sizeof(cmd));
        memset(txBuf, 0, sizeof(txBuf));
        memset(rxBuf, 0, sizeof(rxBuf));

        txBuf[0] = STATUS_REGISTER_READ;
        cmd.tx_cmd = txBuf;
        cmd.rx_cmd = rxBuf;
        cmd.rx_cmd_sz = cmd.tx_cmd_sz = 2;
        err = SPIBUS_TRANSFER(device_get_parent(dev), dev, &cmd);
        *status = rxBuf[1];
        return (err);
}

static int
at45d_get_mfg_info(device_t dev, struct at45d_mfg_info *resp)
{
        uint8_t rxBuf[8], txBuf[8];
        struct spi_command cmd;
        int err;

        memset(&cmd, 0, sizeof(cmd));
        memset(txBuf, 0, sizeof(txBuf));
        memset(rxBuf, 0, sizeof(rxBuf));

        txBuf[0] = MANUFACTURER_ID;
        cmd.tx_cmd = &txBuf;
        cmd.rx_cmd = &rxBuf;
        cmd.tx_cmd_sz = cmd.rx_cmd_sz = 7;
        err = SPIBUS_TRANSFER(device_get_parent(dev), dev, &cmd);
        if (err)
                return (err);

        resp->jedec_id = be32dec(rxBuf + 1);
        resp->ext_id   = be16dec(rxBuf + 5);

        return (0);
}

static int
at45d_wait_ready(device_t dev, uint8_t *status)
{
        struct timeval now, tout;
        int err;

        getmicrouptime(&tout);
        tout.tv_sec += 3;
        do {
                getmicrouptime(&now);
                if (now.tv_sec > tout.tv_sec)
                        err = ETIMEDOUT;
                else
                        err = at45d_get_status(dev, status);
        } while (err == 0 && !(*status & STATUS_READY));
        return (err);
}

static int
at45d_probe(device_t dev)
{
        int rv;

#ifdef FDT
        if (!ofw_bus_status_okay(dev))
                return (ENXIO);

        if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
                return (ENXIO);

        rv = BUS_PROBE_DEFAULT;
#else
        rv = BUS_PROBE_NOWILDCARD;
#endif

        device_set_desc(dev, "AT45D Flash Family");
        return (rv);
}

static int
at45d_attach(device_t dev)
{
        struct at45d_softc *sc;

        sc = device_get_softc(dev);
        sc->dev = dev;
        AT45D_LOCK_INIT(sc);

        config_intrhook_oneshot(at45d_delayed_attach, sc);
        return (0);
}

static int
at45d_detach(device_t dev)
{
        struct at45d_softc *sc;
        int err;

        sc = device_get_softc(dev);
        err = 0;

        AT45D_LOCK(sc);
        if (sc->taskstate == TSTATE_RUNNING) {
                sc->taskstate = TSTATE_STOPPING;
                wakeup(sc);
                while (err == 0 && sc->taskstate != TSTATE_STOPPED) {
                        err = msleep(sc, &sc->sc_mtx, 0, "at45dt", hz * 3);
                        if (err != 0) {
                                sc->taskstate = TSTATE_RUNNING;
                                device_printf(sc->dev,
                                    "Failed to stop queue task\n");
                        }
                }
        }
        AT45D_UNLOCK(sc);

        if (err == 0 && sc->taskstate == TSTATE_STOPPED) {
                if (sc->disk) {
                        disk_destroy(sc->disk);
                        bioq_flush(&sc->bio_queue, NULL, ENXIO);
                        free(sc->dummybuf, M_DEVBUF);
                }
                AT45D_LOCK_DESTROY(sc);
        }
        return (err);
}

static void
at45d_delayed_attach(void *xsc)
{
        struct at45d_softc *sc;
        struct at45d_mfg_info mfginfo;
        const struct at45d_flash_ident *ident;
        u_int i;
        int sectorsize;
        uint32_t jedec;
        uint16_t pagesize;
        uint8_t status;

        sc = xsc;
        ident = NULL;
        jedec = 0;

        if (at45d_wait_ready(sc->dev, &status) != 0) {
                device_printf(sc->dev, "Error waiting for device-ready.\n");
                return;
        }
        if (at45d_get_mfg_info(sc->dev, &mfginfo) != 0) {
                device_printf(sc->dev, "Failed to get ID.\n");
                return;
        }
        for (i = 0; i < nitems(at45d_flash_devices); i++) {
                ident = &at45d_flash_devices[i];
                if (mfginfo.jedec_id == ident->jedec && 
                    (mfginfo.ext_id & ident->extmask) == ident->extid) {
                        break;
                }
        }
        if (i == nitems(at45d_flash_devices)) {
                device_printf(sc->dev, "JEDEC 0x%x not in list.\n", jedec);
                return;
        }

        sc->pagecount = ident->pagecount;
        sc->pageoffset = ident->pageoffset;
        if (ident->pagesize2n != 0 && (status & STATUS_PAGE2N)) {
                sc->pageoffset -= 1;
                pagesize = ident->pagesize2n;
        } else
                pagesize = ident->pagesize;
        sc->pagesize = pagesize;

        /*
         * By default we set up a disk with a sector size that matches the
         * device page size.  If there is a device hint or fdt property
         * requesting a different size, use that, as long as it is a multiple of
         * the device page size).
         */
        sectorsize = pagesize;
#ifdef FDT
        {
                pcell_t size;
                if (OF_getencprop(ofw_bus_get_node(sc->dev),
                    "freebsd,sectorsize", &size, sizeof(size)) > 0)
                        sectorsize = size;
        }
#endif
        resource_int_value(device_get_name(sc->dev), device_get_unit(sc->dev),
            "sectorsize", &sectorsize);

        if ((sectorsize % pagesize) != 0) {
                device_printf(sc->dev, "Invalid sectorsize %d, "
                    "must be a multiple of %d\n", sectorsize, pagesize);
                return;
        }

        sc->dummybuf = malloc(pagesize, M_DEVBUF, M_WAITOK | M_ZERO);

        sc->disk = disk_alloc();
        sc->disk->d_open = at45d_open;
        sc->disk->d_close = at45d_close;
        sc->disk->d_strategy = at45d_strategy;
        sc->disk->d_getattr = at45d_getattr;
        sc->disk->d_name = "flash/at45d";
        sc->disk->d_drv1 = sc;
        sc->disk->d_maxsize = DFLTPHYS;
        sc->disk->d_sectorsize = sectorsize;
        sc->disk->d_mediasize = pagesize * ident->pagecount;
        sc->disk->d_unit = device_get_unit(sc->dev);
        disk_create(sc->disk, DISK_VERSION);
        bioq_init(&sc->bio_queue);
        kproc_create(&at45d_task, sc, &sc->p, 0, 0, "task: at45d flash");
        sc->taskstate = TSTATE_RUNNING;
        device_printf(sc->dev,
            "%s, %d bytes per page, %d pages; %d KBytes; disk sector size %d\n",
            ident->name, pagesize, ident->pagecount,
            (pagesize * ident->pagecount) / 1024, sectorsize);
}

static int
at45d_open(struct disk *dp)
{

        return (0);
}

static int
at45d_close(struct disk *dp)
{

        return (0);
}

static int
at45d_getattr(struct bio *bp)
{
        struct at45d_softc *sc;

        /*
         * This function exists to support geom_flashmap and fdt_slicer.
         */

        if (bp->bio_disk == NULL || bp->bio_disk->d_drv1 == NULL)
                return (ENXIO);
        if (strcmp(bp->bio_attribute, "SPI::device") != 0)
                return (-1);
        sc = bp->bio_disk->d_drv1;
        if (bp->bio_length != sizeof(sc->dev))
                return (EFAULT);
        bcopy(&sc->dev, bp->bio_data, sizeof(sc->dev));
        return (0);
}

static void
at45d_strategy(struct bio *bp)
{
        struct at45d_softc *sc;

        sc = (struct at45d_softc *)bp->bio_disk->d_drv1;
        AT45D_LOCK(sc);
        bioq_disksort(&sc->bio_queue, bp);
        wakeup(sc);
        AT45D_UNLOCK(sc);
}

static void
at45d_task(void *arg)
{
        uint8_t rxBuf[8], txBuf[8];
        struct at45d_softc *sc;
        struct bio *bp;
        struct spi_command cmd;
        device_t dev, pdev;
        caddr_t buf;
        u_long len, resid;
        u_int addr, berr, err, offset, page;
        uint8_t status;

        sc = (struct at45d_softc*)arg;
        dev = sc->dev;
        pdev = device_get_parent(dev);
        memset(&cmd, 0, sizeof(cmd));
        memset(txBuf, 0, sizeof(txBuf));
        memset(rxBuf, 0, sizeof(rxBuf));
        cmd.tx_cmd = txBuf;
        cmd.rx_cmd = rxBuf;

        for (;;) {
                AT45D_LOCK(sc);
                do {
                        if (sc->taskstate == TSTATE_STOPPING) {
                                sc->taskstate = TSTATE_STOPPED;
                                AT45D_UNLOCK(sc);
                                wakeup(sc);
                                kproc_exit(0);
                        }
                        bp = bioq_takefirst(&sc->bio_queue);
                        if (bp == NULL)
                                msleep(sc, &sc->sc_mtx, PRIBIO, "at45dq", 0);
                } while (bp == NULL);
                AT45D_UNLOCK(sc);

                berr = 0;
                buf = bp->bio_data;
                len = resid = bp->bio_bcount;
                page = bp->bio_offset / sc->pagesize;
                offset = bp->bio_offset % sc->pagesize;

                switch (bp->bio_cmd) {
                case BIO_READ:
                        txBuf[0] = CONTINUOUS_ARRAY_READ;
                        cmd.tx_cmd_sz = cmd.rx_cmd_sz = 8;
                        cmd.tx_data = sc->dummybuf;
                        cmd.rx_data = buf;
                        break;
                case BIO_WRITE:
                        cmd.tx_cmd_sz = cmd.rx_cmd_sz = 4;
                        cmd.tx_data = buf;
                        cmd.rx_data = sc->dummybuf;
                        if (resid + offset > sc->pagesize)
                                len = sc->pagesize - offset;
                        break;
                default:
                        berr = EOPNOTSUPP;
                        goto out;
                }

                /*
                 * NB: for BIO_READ, this loop is only traversed once.
                 */
                while (resid > 0) {
                        if (page > sc->pagecount) {
                                berr = EINVAL;
                                goto out;
                        }
                        addr = page << sc->pageoffset;
                        if (bp->bio_cmd == BIO_WRITE) {
                                /*
                                 * If writing less than a full page, transfer
                                 * the existing page to the buffer, so that our
                                 * PROGRAM_THROUGH_BUFFER below will preserve
                                 * the parts of the page we're not writing.
                                 */
                                if (len != sc->pagesize) {
                                        txBuf[0] = PAGE_TO_BUFFER_TRANSFER;
                                        txBuf[1] = ((addr >> 16) & 0xff);
                                        txBuf[2] = ((addr >> 8) & 0xff);
                                        txBuf[3] = 0;
                                        cmd.tx_data_sz = cmd.rx_data_sz = 0;
                                        err = SPIBUS_TRANSFER(pdev, dev, &cmd);
                                        if (err == 0)
                                                err = at45d_wait_ready(dev,
                                                    &status);
                                        if (err != 0) {
                                                berr = EIO;
                                                goto out;
                                        }
                                }
                                txBuf[0] = PROGRAM_THROUGH_BUFFER;
                        }

                        addr += offset;
                        txBuf[1] = ((addr >> 16) & 0xff);
                        txBuf[2] = ((addr >> 8) & 0xff);
                        txBuf[3] = (addr & 0xff);
                        cmd.tx_data_sz = cmd.rx_data_sz = len;
                        err = SPIBUS_TRANSFER(pdev, dev, &cmd);
                        if (err == 0 && bp->bio_cmd != BIO_READ)
                                err = at45d_wait_ready(dev, &status);
                        if (err != 0) {
                                berr = EIO;
                                goto out;
                        }
                        if (bp->bio_cmd == BIO_WRITE) {
                                addr = page << sc->pageoffset;
                                txBuf[0] = PAGE_TO_BUFFER_COMPARE;
                                txBuf[1] = ((addr >> 16) & 0xff);
                                txBuf[2] = ((addr >> 8) & 0xff);
                                txBuf[3] = 0;
                                cmd.tx_data_sz = cmd.rx_data_sz = 0;
                                err = SPIBUS_TRANSFER(pdev, dev, &cmd);
                                if (err == 0)
                                        err = at45d_wait_ready(dev, &status);
                                if (err != 0 || (status & STATUS_CMPFAIL)) {
                                        device_printf(dev, "comparing page "
                                            "%d failed (status=0x%x)\n", page,
                                            status);
                                        berr = EIO;
                                        goto out;
                                }
                        }
                        page++;
                        buf += len;
                        offset = 0;
                        resid -= len;
                        if (resid > sc->pagesize)
                                len = sc->pagesize;
                        else
                                len = resid;
                        if (bp->bio_cmd == BIO_READ)
                                cmd.rx_data = buf;
                        else
                                cmd.tx_data = buf;
                }
 out:
                if (berr != 0) {
                        bp->bio_flags |= BIO_ERROR;
                        bp->bio_error = berr;
                }
                bp->bio_resid = resid;
                biodone(bp);
        }
}

static device_method_t at45d_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,         at45d_probe),
        DEVMETHOD(device_attach,        at45d_attach),
        DEVMETHOD(device_detach,        at45d_detach),

        DEVMETHOD_END
};

static driver_t at45d_driver = {
        "at45d",
        at45d_methods,
        sizeof(struct at45d_softc),
};

DRIVER_MODULE(at45d, spibus, at45d_driver, NULL, NULL);
MODULE_DEPEND(at45d, spibus, 1, 1, 1);
#ifdef FDT
MODULE_DEPEND(at45d, fdt_slicer, 1, 1, 1);
SPIBUS_FDT_PNP_INFO(compat_data);
#endif