/*-
 * Copyright (c) 2006 M. Warner Losh
 * Copyright (c) 2011-2012 Ian Lepore
 * Copyright (c) 2012 Marius Strobl <marius@FreeBSD.org>
 * All rights reserved.
 *
 * 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/cdefs.h>
__FBSDID("$FreeBSD$");

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

struct at45d_flash_ident
{
	const char	*name;
	uint32_t	jedec;
	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;
	struct intr_config_hook	config_intrhook;
	device_t		dev;
	uint16_t		pagecount;
	uint16_t		pageoffset;
	uint16_t		pagesize;
};

#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 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, uint8_t *resp);
static int at45d_get_status(device_t dev, uint8_t *status);
static int at45d_wait_ready(device_t dev, uint8_t *status);

#define	BUFFER_TRANSFER			0x53
#define	BUFFER_COMPARE			0x60
#define	PROGRAM_THROUGH_BUFFER		0x82
#define	MANUFACTURER_ID			0x9f
#define	STATUS_REGISTER_READ		0xd7
#define	CONTINUOUS_ARRAY_READ		0xe8

/*
 * 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[] = {
	{ "AT45DB011B", 0x1f2200, 512, 9, 264, 256 },
	{ "AT45DB021B", 0x1f2300, 1024, 9, 264, 256 },
	{ "AT45DB041x", 0x1f2400, 2028, 9, 264, 256 },
	{ "AT45DB081B", 0x1f2500, 4096, 9, 264, 256 },
	{ "AT45DB161x", 0x1f2600, 4096, 10, 528, 512 },
	{ "AT45DB321x", 0x1f2700, 8192, 10, 528, 0 },
	{ "AT45DB321x", 0x1f2701, 8192, 10, 528, 512 },
	{ "AT45DB642x", 0x1f2800, 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, uint8_t *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 = 5;
	err = SPIBUS_TRANSFER(device_get_parent(dev), dev, &cmd);
	if (err)
		return (err);
	memcpy(resp, rxBuf + 1, 4);
	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 & 0x80) == 0);
	return (err);
}

static int
at45d_probe(device_t dev)
{

	device_set_desc(dev, "AT45D Flash Family");
	return (0);
}

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

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

	/* We'll see what kind of flash we have later... */
	sc->config_intrhook.ich_func = at45d_delayed_attach;
	sc->config_intrhook.ich_arg = sc;
	if (config_intrhook_establish(&sc->config_intrhook) != 0)
		device_printf(dev, "config_intrhook_establish failed\n");
	return (0);
}

static int
at45d_detach(device_t dev)
{

	return (EBUSY) /* XXX */;
}

static void
at45d_delayed_attach(void *xsc)
{
	struct at45d_softc *sc;
	const struct at45d_flash_ident *ident;
	u_int i;
	uint32_t jedec;
	uint16_t pagesize;
	uint8_t buf[4], 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");
	else if (at45d_get_mfg_info(sc->dev, buf) != 0)
		device_printf(sc->dev, "Failed to get ID.\n");
	else {
		jedec = buf[0] << 16 | buf[1] << 8 | buf[2];
		for (i = 0; i < nitems(at45d_flash_devices); i++) {
			if (at45d_flash_devices[i].jedec == jedec) {
				ident = &at45d_flash_devices[i];
				break;
			}
		}
	}
	if (ident == NULL)
		device_printf(sc->dev, "JEDEC 0x%x not in list.\n", jedec);
	else {
		sc->pagecount = ident->pagecount;
		sc->pageoffset = ident->pageoffset;
		if (ident->pagesize2n != 0 && (status & 0x01) != 0) {
			sc->pageoffset -= 1;
			pagesize = ident->pagesize2n;
		} else
			pagesize = ident->pagesize;
		sc->pagesize = pagesize;

		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_name = "flash/spi";
		sc->disk->d_drv1 = sc;
		sc->disk->d_maxsize = DFLTPHYS;
		sc->disk->d_sectorsize = pagesize;
		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");
		device_printf(sc->dev, "%s, %d bytes per page, %d pages\n",
		    ident->name, pagesize, ident->pagecount);
	}

	config_intrhook_disestablish(&sc->config_intrhook);
}

static int
at45d_open(struct disk *dp)
{

	return (0);
}

static int
at45d_close(struct disk *dp)
{

	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 {
			bp = bioq_takefirst(&sc->bio_queue);
			if (bp == NULL)
				msleep(sc, &sc->sc_mtx, PRIBIO, "jobqueue", 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 = cmd.rx_data = buf;
			break;
		case BIO_WRITE:
			cmd.tx_cmd_sz = cmd.rx_cmd_sz = 4;
			cmd.tx_data = cmd.rx_data = buf;
			if (resid + offset > sc->pagesize)
				len = sc->pagesize - offset;
			break;
		default:
			berr = EINVAL;
			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 (len != sc->pagesize) {
					txBuf[0] = 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] = 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 & 0x40) != 0) {
					device_printf(dev, "comparing page "
					    "%d failed (status=0x%x)\n", addr,
					    status);
					berr = EIO;
					goto out;
				}
			}
			page++;
			buf += len;
			offset = 0;
			resid -= len;
			if (resid > sc->pagesize)
				len = sc->pagesize;
			else
				len = resid;
			cmd.tx_data = cmd.rx_data = buf;
		}
 out:
		if (berr != 0) {
			bp->bio_flags |= BIO_ERROR;
			bp->bio_error = berr;
		}
		bp->bio_resid = resid;
		biodone(bp);
	}
}

static devclass_t at45d_devclass;

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, at45d_devclass, NULL, NULL);