/*-
 * Copyright (c) 2009 Oleksandr Tymoshenko.  All rights reserved.
 * Copyright (c) 2017 Ruslan Bukin <br@bsdpad.com>
 * Copyright (c) 2018 Ian Lepore.  All rights reserved.
 * Copyright (c) 2006 M. Warner Losh <imp@FreeBSD.org>
 *
 * This software was developed by SRI International and the University of
 * Cambridge Computer Laboratory under DARPA/AFRL contract FA8750-10-C-0237
 * ("CTSRD"), as part of the DARPA CRASH research programme.
 *
 * 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 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 AUTHOR 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.
 */

/* n25q Quad SPI Flash driver. */

#include <sys/cdefs.h>
#include "opt_platform.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bio.h>
#include <sys/bus.h>
#include <sys/conf.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 <machine/bus.h>

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

#include <dev/flash/mx25lreg.h>

#include "qspi_if.h"

#define N25Q_DEBUG
#undef N25Q_DEBUG

#ifdef N25Q_DEBUG
#define dprintf(fmt, ...)  printf(fmt, ##__VA_ARGS__)
#else
#define dprintf(fmt, ...)
#endif

#define FL_NONE                 0x00
#define FL_ERASE_4K             0x01
#define FL_ERASE_32K            0x02
#define FL_ENABLE_4B_ADDR       0x04
#define FL_DISABLE_4B_ADDR      0x08

/*
 * Define the sectorsize to be a smaller size rather than the flash
 * sector size. Trying to run FFS off of a 64k flash sector size
 * results in a completely un-usable system.
 */
#define FLASH_SECTORSIZE        512

struct n25q_flash_ident {
        const char      *name;
        uint8_t         manufacturer_id;
        uint16_t        device_id;
        unsigned int    sectorsize;
        unsigned int    sectorcount;
        unsigned int    flags;
};

struct n25q_softc {
        device_t                dev;
        bus_space_tag_t         bst;
        bus_space_handle_t      bsh;
        void                    *ih;
        struct resource         *res[3];

        uint8_t                 sc_manufacturer_id;
        uint16_t                device_id;
        unsigned int            sc_sectorsize;
        struct mtx              sc_mtx;
        struct disk             *sc_disk;
        struct proc             *sc_p;
        struct bio_queue_head   sc_bio_queue;
        unsigned int            sc_flags;
        unsigned int            sc_taskstate;
};

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

#define N25Q_LOCK(_sc)          mtx_lock(&(_sc)->sc_mtx)
#define N25Q_UNLOCK(_sc)        mtx_unlock(&(_sc)->sc_mtx)
#define N25Q_LOCK_INIT(_sc)                                     \
        mtx_init(&_sc->sc_mtx, device_get_nameunit(_sc->dev),   \
            "n25q", MTX_DEF)
#define N25Q_LOCK_DESTROY(_sc)  mtx_destroy(&_sc->sc_mtx);
#define N25Q_ASSERT_LOCKED(_sc)                         \
        mtx_assert(&_sc->sc_mtx, MA_OWNED);
#define N25Q_ASSERT_UNLOCKED(_sc)                               \
        mtx_assert(&_sc->sc_mtx, MA_NOTOWNED);

static struct ofw_compat_data compat_data[] = {
        { "n25q00aa",           1 },
        { NULL,                 0 },
};

/* disk routines */
static int n25q_open(struct disk *dp);
static int n25q_close(struct disk *dp);
static int n25q_ioctl(struct disk *, u_long, void *, int, struct thread *);
static void n25q_strategy(struct bio *bp);
static int n25q_getattr(struct bio *bp);
static void n25q_task(void *arg);

static struct n25q_flash_ident flash_devices[] = {
        { "n25q00", 0x20, 0xbb21, (64 * 1024), 2048, FL_ENABLE_4B_ADDR},
};

static int
n25q_wait_for_device_ready(device_t dev)
{
        device_t pdev;
        uint8_t status;
        int err;

        pdev = device_get_parent(dev);

        do {
                err = QSPI_READ_REG(pdev, dev, CMD_READ_STATUS, &status, 1);
        } while (err == 0 && (status & STATUS_WIP));

        return (err);
}

static struct n25q_flash_ident*
n25q_get_device_ident(struct n25q_softc *sc)
{
        uint8_t manufacturer_id;
        uint16_t dev_id;
        device_t pdev;
        uint8_t data[4];
        int i;

        pdev = device_get_parent(sc->dev);

        QSPI_READ_REG(pdev, sc->dev, CMD_READ_IDENT, (uint8_t *)&data[0], 4);

        manufacturer_id = data[0];
        dev_id = (data[1] << 8) | (data[2]);

        for (i = 0; i < nitems(flash_devices); i++) {
                if ((flash_devices[i].manufacturer_id == manufacturer_id) &&
                    (flash_devices[i].device_id == dev_id))
                        return &flash_devices[i];
        }

        printf("Unknown SPI flash device. Vendor: %02x, device id: %04x\n",
            manufacturer_id, dev_id);

        return (NULL);
}

static int
n25q_write(device_t dev, struct bio *bp, off_t offset, caddr_t data, off_t count)
{
        device_t pdev;
        int err;

        pdev = device_get_parent(dev);

        dprintf("%s: offset 0x%llx count %lld bytes\n", __func__, offset, count);

        err = QSPI_ERASE(pdev, dev, offset);
        if (err != 0) {
                return (err);
        }

        err = QSPI_WRITE(pdev, dev, bp, offset, data, count);

        return (err);
}

static int
n25q_read(device_t dev, struct bio *bp, off_t offset, caddr_t data, off_t count)
{
        struct n25q_softc *sc;
        device_t pdev;
        int err;

        pdev = device_get_parent(dev);
        sc = device_get_softc(dev);

        dprintf("%s: offset 0x%llx count %lld bytes\n", __func__, offset, count);

        /*
         * Enforce the disk read sectorsize not the erase sectorsize.
         * In this way, smaller read IO is possible,dramatically
         * speeding up filesystem/geom_compress access.
         */
        if (count % sc->sc_disk->d_sectorsize != 0
            || offset % sc->sc_disk->d_sectorsize != 0) {
                printf("EIO\n");
                return (EIO);
        }

        err = QSPI_READ(pdev, dev, bp, offset, data, count);

        return (err);
}

static int
n25q_set_4b_mode(device_t dev, uint8_t command)
{
        device_t pdev;
        int err;

        pdev = device_get_parent(dev);

        err = QSPI_WRITE_REG(pdev, dev, command, 0, 0);

        return (err);
}

static int
n25q_probe(device_t dev)
{
        int i;

        if (!ofw_bus_status_okay(dev))
                return (ENXIO);

        /* First try to match the compatible property to the compat_data */
        if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 1)
                goto found;

        /*
         * Next, try to find a compatible device using the names in the
         * flash_devices structure
         */
        for (i = 0; i < nitems(flash_devices); i++)
                if (ofw_bus_is_compatible(dev, flash_devices[i].name))
                        goto found;

        return (ENXIO);
found:
        device_set_desc(dev, "Micron n25q");

        return (0);
}

static int
n25q_attach(device_t dev)
{
        struct n25q_flash_ident *ident;
        struct n25q_softc *sc;

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

        N25Q_LOCK_INIT(sc);

        ident = n25q_get_device_ident(sc);
        if (ident == NULL) {
                return (ENXIO);
        }

        n25q_wait_for_device_ready(sc->dev);

        sc->sc_disk = disk_alloc();
        sc->sc_disk->d_open = n25q_open;
        sc->sc_disk->d_close = n25q_close;
        sc->sc_disk->d_strategy = n25q_strategy;
        sc->sc_disk->d_getattr = n25q_getattr;
        sc->sc_disk->d_ioctl = n25q_ioctl;
        sc->sc_disk->d_name = "flash/qspi";
        sc->sc_disk->d_drv1 = sc;
        sc->sc_disk->d_maxsize = DFLTPHYS;
        sc->sc_disk->d_sectorsize = FLASH_SECTORSIZE;
        sc->sc_disk->d_mediasize = (ident->sectorsize * ident->sectorcount);
        sc->sc_disk->d_unit = device_get_unit(sc->dev);
        sc->sc_disk->d_dump = NULL;
        /* Sectorsize for erase operations */
        sc->sc_sectorsize =  ident->sectorsize;
        sc->sc_flags = ident->flags;

        if (sc->sc_flags & FL_ENABLE_4B_ADDR)
                n25q_set_4b_mode(dev, CMD_ENTER_4B_MODE);

        if (sc->sc_flags & FL_DISABLE_4B_ADDR)
                n25q_set_4b_mode(dev, CMD_EXIT_4B_MODE);

        /* NB: use stripesize to hold the erase/region size for RedBoot */
        sc->sc_disk->d_stripesize = ident->sectorsize;

        disk_create(sc->sc_disk, DISK_VERSION);
        bioq_init(&sc->sc_bio_queue);

        kproc_create(&n25q_task, sc, &sc->sc_p, 0, 0, "task: n25q flash");
        sc->sc_taskstate = TSTATE_RUNNING;

        device_printf(sc->dev, "%s, sector %d bytes, %d sectors\n", 
            ident->name, ident->sectorsize, ident->sectorcount);

        return (0);
}

static int
n25q_detach(device_t dev)
{
        struct n25q_softc *sc;
        int err;

        sc = device_get_softc(dev);
        err = 0;

        N25Q_LOCK(sc);
        if (sc->sc_taskstate == TSTATE_RUNNING) {
                sc->sc_taskstate = TSTATE_STOPPING;
                wakeup(sc);
                while (err == 0 && sc->sc_taskstate != TSTATE_STOPPED) {
                        err = msleep(sc, &sc->sc_mtx, 0, "n25q", hz * 3);
                        if (err != 0) {
                                sc->sc_taskstate = TSTATE_RUNNING;
                                device_printf(sc->dev,
                                    "Failed to stop queue task\n");
                        }
                }
        }
        N25Q_UNLOCK(sc);

        if (err == 0 && sc->sc_taskstate == TSTATE_STOPPED) {
                disk_destroy(sc->sc_disk);
                bioq_flush(&sc->sc_bio_queue, NULL, ENXIO);
                N25Q_LOCK_DESTROY(sc);
        }
        return (err);
}

static int
n25q_open(struct disk *dp)
{

        return (0);
}

static int
n25q_close(struct disk *dp)
{

        return (0);
}

static int
n25q_ioctl(struct disk *dp, u_long cmd, void *data,
    int fflag, struct thread *td)
{

        return (EINVAL);
}

static void
n25q_strategy(struct bio *bp)
{
        struct n25q_softc *sc;

        sc = (struct n25q_softc *)bp->bio_disk->d_drv1;

        N25Q_LOCK(sc);
        bioq_disksort(&sc->sc_bio_queue, bp);
        wakeup(sc);
        N25Q_UNLOCK(sc);
}

static int
n25q_getattr(struct bio *bp)
{
        struct n25q_softc *sc;
        device_t dev;

        if (bp->bio_disk == NULL || bp->bio_disk->d_drv1 == NULL) {
                return (ENXIO);
        }

        sc = bp->bio_disk->d_drv1;
        dev = sc->dev;

        if (strcmp(bp->bio_attribute, "SPI::device") == 0) {
                if (bp->bio_length != sizeof(dev)) {
                        return (EFAULT);
                }
                bcopy(&dev, bp->bio_data, sizeof(dev));
                return (0);
        }

        return (-1);
}

static void
n25q_task(void *arg)
{
        struct n25q_softc *sc;
        struct bio *bp;
        device_t dev;

        sc = (struct n25q_softc *)arg;

        dev = sc->dev;

        for (;;) {
                N25Q_LOCK(sc);
                do {
                        if (sc->sc_taskstate == TSTATE_STOPPING) {
                                sc->sc_taskstate = TSTATE_STOPPED;
                                N25Q_UNLOCK(sc);
                                wakeup(sc);
                                kproc_exit(0);
                        }
                        bp = bioq_first(&sc->sc_bio_queue);
                        if (bp == NULL)
                                msleep(sc, &sc->sc_mtx, PRIBIO, "jobqueue", hz);
                } while (bp == NULL);
                bioq_remove(&sc->sc_bio_queue, bp);
                N25Q_UNLOCK(sc);

                switch (bp->bio_cmd) {
                case BIO_READ:
                        bp->bio_error = n25q_read(dev, bp, bp->bio_offset, 
                            bp->bio_data, bp->bio_bcount);
                        break;
                case BIO_WRITE:
                        bp->bio_error = n25q_write(dev, bp, bp->bio_offset, 
                            bp->bio_data, bp->bio_bcount);
                        break;
                default:
                        bp->bio_error = EOPNOTSUPP;
                }

                biodone(bp);
        }
}

static device_method_t n25q_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,         n25q_probe),
        DEVMETHOD(device_attach,        n25q_attach),
        DEVMETHOD(device_detach,        n25q_detach),

        DEVMETHOD_END
};

static driver_t n25q_driver = {
        "n25q",
        n25q_methods,
        sizeof(struct n25q_softc),
};

DRIVER_MODULE(n25q, simplebus, n25q_driver, 0, 0);