/*-
 * 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),

	{ 0, 0 }
};

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

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