/*
 * MTD driver for Alauda chips
 *
 * Copyright (C) 2007 Joern Engel <joern@logfs.org>
 *
 * Based on drivers/usb/usb-skeleton.c which is:
 * Copyright (C) 2001-2004 Greg Kroah-Hartman (greg@kroah.com)
 * and on drivers/usb/storage/alauda.c, which is:
 *   (c) 2005 Daniel Drake <dsd@gentoo.org>
 *
 * Idea and initial work by Arnd Bergmann <arnd@arndb.de>
 */
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/kref.h>
#include <linux/usb.h>
#include <linux/mutex.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/nand_ecc.h>

/* Control commands */
#define ALAUDA_GET_XD_MEDIA_STATUS	0x08
#define ALAUDA_ACK_XD_MEDIA_CHANGE	0x0a
#define ALAUDA_GET_XD_MEDIA_SIG		0x86

/* Common prefix */
#define ALAUDA_BULK_CMD			0x40

/* The two ports */
#define ALAUDA_PORT_XD			0x00
#define ALAUDA_PORT_SM			0x01

/* Bulk commands */
#define ALAUDA_BULK_READ_PAGE		0x84
#define ALAUDA_BULK_READ_OOB		0x85 /* don't use, there's a chip bug */
#define ALAUDA_BULK_READ_BLOCK		0x94
#define ALAUDA_BULK_ERASE_BLOCK		0xa3
#define ALAUDA_BULK_WRITE_PAGE		0xa4
#define ALAUDA_BULK_WRITE_BLOCK		0xb4
#define ALAUDA_BULK_RESET_MEDIA		0xe0

/* Address shifting */
#define PBA_LO(pba) ((pba & 0xF) << 5)
#define PBA_HI(pba) (pba >> 3)
#define PBA_ZONE(pba) (pba >> 11)

#define TIMEOUT HZ

static struct usb_device_id alauda_table [] = {
	{ USB_DEVICE(0x0584, 0x0008) },	/* Fujifilm DPC-R1 */
	{ USB_DEVICE(0x07b4, 0x010a) },	/* Olympus MAUSB-10 */
	{ }
};
MODULE_DEVICE_TABLE(usb, alauda_table);

struct alauda_card {
	u8	id;		/* id byte */
	u8	chipshift;	/* 1<<chipshift total size */
	u8	pageshift;	/* 1<<pageshift page size */
	u8	blockshift;	/* 1<<blockshift block size */
};

struct alauda {
	struct usb_device	*dev;
	struct usb_interface	*interface;
	struct mtd_info		*mtd;
	struct alauda_card	*card;
	struct mutex		card_mutex;
	u32			pagemask;
	u32			bytemask;
	u32			blockmask;
	unsigned int		write_out;
	unsigned int		bulk_in;
	unsigned int		bulk_out;
	u8			port;
	struct kref		kref;
};

static struct alauda_card alauda_card_ids[] = {
	/* NAND flash */
	{ 0x6e, 20, 8, 12},	/* 1 MB */
	{ 0xe8, 20, 8, 12},	/* 1 MB */
	{ 0xec, 20, 8, 12},	/* 1 MB */
	{ 0x64, 21, 8, 12},	/* 2 MB */
	{ 0xea, 21, 8, 12},	/* 2 MB */
	{ 0x6b, 22, 9, 13},	/* 4 MB */
	{ 0xe3, 22, 9, 13},	/* 4 MB */
	{ 0xe5, 22, 9, 13},	/* 4 MB */
	{ 0xe6, 23, 9, 13},	/* 8 MB */
	{ 0x73, 24, 9, 14},	/* 16 MB */
	{ 0x75, 25, 9, 14},	/* 32 MB */
	{ 0x76, 26, 9, 14},	/* 64 MB */
	{ 0x79, 27, 9, 14},	/* 128 MB */
	{ 0x71, 28, 9, 14},	/* 256 MB */

	/* MASK ROM */
	{ 0x5d, 21, 9, 13},	/* 2 MB */
	{ 0xd5, 22, 9, 13},	/* 4 MB */
	{ 0xd6, 23, 9, 13},	/* 8 MB */
	{ 0x57, 24, 9, 13},	/* 16 MB */
	{ 0x58, 25, 9, 13},	/* 32 MB */
	{ }
};

static struct alauda_card *get_card(u8 id)
{
	struct alauda_card *card;

	for (card = alauda_card_ids; card->id; card++)
		if (card->id == id)
			return card;
	return NULL;
}

static void alauda_delete(struct kref *kref)
{
	struct alauda *al = container_of(kref, struct alauda, kref);

	if (al->mtd) {
		del_mtd_device(al->mtd);
		kfree(al->mtd);
	}
	usb_put_dev(al->dev);
	kfree(al);
}

static int alauda_get_media_status(struct alauda *al, void *buf)
{
	int ret;

	mutex_lock(&al->card_mutex);
	ret = usb_control_msg(al->dev, usb_rcvctrlpipe(al->dev, 0),
			ALAUDA_GET_XD_MEDIA_STATUS, 0xc0, 0, 1, buf, 2, HZ);
	mutex_unlock(&al->card_mutex);
	return ret;
}

static int alauda_ack_media(struct alauda *al)
{
	int ret;

	mutex_lock(&al->card_mutex);
	ret = usb_control_msg(al->dev, usb_sndctrlpipe(al->dev, 0),
			ALAUDA_ACK_XD_MEDIA_CHANGE, 0x40, 0, 1, NULL, 0, HZ);
	mutex_unlock(&al->card_mutex);
	return ret;
}

static int alauda_get_media_signatures(struct alauda *al, void *buf)
{
	int ret;

	mutex_lock(&al->card_mutex);
	ret = usb_control_msg(al->dev, usb_rcvctrlpipe(al->dev, 0),
			ALAUDA_GET_XD_MEDIA_SIG, 0xc0, 0, 0, buf, 4, HZ);
	mutex_unlock(&al->card_mutex);
	return ret;
}

static void alauda_reset(struct alauda *al)
{
	u8 command[] = {
		ALAUDA_BULK_CMD, ALAUDA_BULK_RESET_MEDIA, 0, 0,
		0, 0, 0, 0, al->port
	};
	mutex_lock(&al->card_mutex);
	usb_bulk_msg(al->dev, al->bulk_out, command, 9, NULL, HZ);
	mutex_unlock(&al->card_mutex);
}

static void correct_data(void *buf, void *read_ecc,
		int *corrected, int *uncorrected)
{
	u8 calc_ecc[3];
	int err;

	nand_calculate_ecc(NULL, buf, calc_ecc);
	err = nand_correct_data(NULL, buf, read_ecc, calc_ecc);
	if (err) {
		if (err > 0)
			(*corrected)++;
		else
			(*uncorrected)++;
	}
}

struct alauda_sg_request {
	struct urb *urb[3];
	struct completion comp;
};

static void alauda_complete(struct urb *urb)
{
	struct completion *comp = urb->context;

	if (comp)
		complete(comp);
}

static int __alauda_read_page(struct mtd_info *mtd, loff_t from, void *buf,
		void *oob)
{
	struct alauda_sg_request sg;
	struct alauda *al = mtd->priv;
	u32 pba = from >> al->card->blockshift;
	u32 page = (from >> al->card->pageshift) & al->pagemask;
	u8 command[] = {
		ALAUDA_BULK_CMD, ALAUDA_BULK_READ_PAGE, PBA_HI(pba),
		PBA_ZONE(pba), 0, PBA_LO(pba) + page, 1, 0, al->port
	};
	int i, err;

	for (i=0; i<3; i++)
		sg.urb[i] = NULL;

	err = -ENOMEM;
	for (i=0; i<3; i++) {
		sg.urb[i] = usb_alloc_urb(0, GFP_NOIO);
		if (!sg.urb[i])
			goto out;
	}
	init_completion(&sg.comp);
	usb_fill_bulk_urb(sg.urb[0], al->dev, al->bulk_out, command, 9,
			alauda_complete, NULL);
	usb_fill_bulk_urb(sg.urb[1], al->dev, al->bulk_in, buf, mtd->writesize,
			alauda_complete, NULL);
	usb_fill_bulk_urb(sg.urb[2], al->dev, al->bulk_in, oob, 16,
			alauda_complete, &sg.comp);

	mutex_lock(&al->card_mutex);
	for (i=0; i<3; i++) {
		err = usb_submit_urb(sg.urb[i], GFP_NOIO);
		if (err)
			goto cancel;
	}
	if (!wait_for_completion_timeout(&sg.comp, TIMEOUT)) {
		err = -ETIMEDOUT;
cancel:
		for (i=0; i<3; i++) {
			usb_kill_urb(sg.urb[i]);
		}
	}
	mutex_unlock(&al->card_mutex);

out:
	usb_free_urb(sg.urb[0]);
	usb_free_urb(sg.urb[1]);
	usb_free_urb(sg.urb[2]);
	return err;
}

static int alauda_read_page(struct mtd_info *mtd, loff_t from,
		void *buf, u8 *oob, int *corrected, int *uncorrected)
{
	int err;

	err = __alauda_read_page(mtd, from, buf, oob);
	if (err)
		return err;
	correct_data(buf, oob+13, corrected, uncorrected);
	correct_data(buf+256, oob+8, corrected, uncorrected);
	return 0;
}

static int alauda_write_page(struct mtd_info *mtd, loff_t to, void *buf,
		void *oob)
{
	struct alauda_sg_request sg;
	struct alauda *al = mtd->priv;
	u32 pba = to >> al->card->blockshift;
	u32 page = (to >> al->card->pageshift) & al->pagemask;
	u8 command[] = {
		ALAUDA_BULK_CMD, ALAUDA_BULK_WRITE_PAGE, PBA_HI(pba),
		PBA_ZONE(pba), 0, PBA_LO(pba) + page, 32, 0, al->port
	};
	int i, err;

	for (i=0; i<3; i++)
		sg.urb[i] = NULL;

	err = -ENOMEM;
	for (i=0; i<3; i++) {
		sg.urb[i] = usb_alloc_urb(0, GFP_NOIO);
		if (!sg.urb[i])
			goto out;
	}
	init_completion(&sg.comp);
	usb_fill_bulk_urb(sg.urb[0], al->dev, al->bulk_out, command, 9,
			alauda_complete, NULL);
	usb_fill_bulk_urb(sg.urb[1], al->dev, al->write_out, buf,mtd->writesize,
			alauda_complete, NULL);
	usb_fill_bulk_urb(sg.urb[2], al->dev, al->write_out, oob, 16,
			alauda_complete, &sg.comp);

	mutex_lock(&al->card_mutex);
	for (i=0; i<3; i++) {
		err = usb_submit_urb(sg.urb[i], GFP_NOIO);
		if (err)
			goto cancel;
	}
	if (!wait_for_completion_timeout(&sg.comp, TIMEOUT)) {
		err = -ETIMEDOUT;
cancel:
		for (i=0; i<3; i++) {
			usb_kill_urb(sg.urb[i]);
		}
	}
	mutex_unlock(&al->card_mutex);

out:
	usb_free_urb(sg.urb[0]);
	usb_free_urb(sg.urb[1]);
	usb_free_urb(sg.urb[2]);
	return err;
}

static int alauda_erase_block(struct mtd_info *mtd, loff_t ofs)
{
	struct alauda_sg_request sg;
	struct alauda *al = mtd->priv;
	u32 pba = ofs >> al->card->blockshift;
	u8 command[] = {
		ALAUDA_BULK_CMD, ALAUDA_BULK_ERASE_BLOCK, PBA_HI(pba),
		PBA_ZONE(pba), 0, PBA_LO(pba), 0x02, 0, al->port
	};
	u8 buf[2];
	int i, err;

	for (i=0; i<2; i++)
		sg.urb[i] = NULL;

	err = -ENOMEM;
	for (i=0; i<2; i++) {
		sg.urb[i] = usb_alloc_urb(0, GFP_NOIO);
		if (!sg.urb[i])
			goto out;
	}
	init_completion(&sg.comp);
	usb_fill_bulk_urb(sg.urb[0], al->dev, al->bulk_out, command, 9,
			alauda_complete, NULL);
	usb_fill_bulk_urb(sg.urb[1], al->dev, al->bulk_in, buf, 2,
			alauda_complete, &sg.comp);

	mutex_lock(&al->card_mutex);
	for (i=0; i<2; i++) {
		err = usb_submit_urb(sg.urb[i], GFP_NOIO);
		if (err)
			goto cancel;
	}
	if (!wait_for_completion_timeout(&sg.comp, TIMEOUT)) {
		err = -ETIMEDOUT;
cancel:
		for (i=0; i<2; i++) {
			usb_kill_urb(sg.urb[i]);
		}
	}
	mutex_unlock(&al->card_mutex);

out:
	usb_free_urb(sg.urb[0]);
	usb_free_urb(sg.urb[1]);
	return err;
}

static int alauda_read_oob(struct mtd_info *mtd, loff_t from, void *oob)
{
	static u8 ignore_buf[512]; /* write only */

	return __alauda_read_page(mtd, from, ignore_buf, oob);
}

static int popcount8(u8 c)
{
	int ret = 0;

	for ( ; c; c>>=1)
		ret += c & 1;
	return ret;
}

static int alauda_isbad(struct mtd_info *mtd, loff_t ofs)
{
	u8 oob[16];
	int err;

	err = alauda_read_oob(mtd, ofs, oob);
	if (err)
		return err;

	/* A block is marked bad if two or more bits are zero */
	return popcount8(oob[5]) >= 7 ? 0 : 1;
}

static int alauda_bounce_read(struct mtd_info *mtd, loff_t from, size_t len,
		size_t *retlen, u_char *buf)
{
	struct alauda *al = mtd->priv;
	void *bounce_buf;
	int err, corrected=0, uncorrected=0;

	bounce_buf = kmalloc(mtd->writesize, GFP_KERNEL);
	if (!bounce_buf)
		return -ENOMEM;

	*retlen = len;
	while (len) {
		u8 oob[16];
		size_t byte = from & al->bytemask;
		size_t cplen = min(len, mtd->writesize - byte);

		err = alauda_read_page(mtd, from, bounce_buf, oob,
				&corrected, &uncorrected);
		if (err)
			goto out;

		memcpy(buf, bounce_buf + byte, cplen);
		buf += cplen;
		from += cplen;
		len -= cplen;
	}
	err = 0;
	if (corrected)
		err = -EUCLEAN;
	if (uncorrected)
		err = -EBADMSG;
out:
	kfree(bounce_buf);
	return err;
}

static int alauda_read(struct mtd_info *mtd, loff_t from, size_t len,
		size_t *retlen, u_char *buf)
{
	struct alauda *al = mtd->priv;
	int err, corrected=0, uncorrected=0;

	if ((from & al->bytemask) || (len & al->bytemask))
		return alauda_bounce_read(mtd, from, len, retlen, buf);

	*retlen = len;
	while (len) {
		u8 oob[16];

		err = alauda_read_page(mtd, from, buf, oob,
				&corrected, &uncorrected);
		if (err)
			return err;

		buf += mtd->writesize;
		from += mtd->writesize;
		len -= mtd->writesize;
	}
	err = 0;
	if (corrected)
		err = -EUCLEAN;
	if (uncorrected)
		err = -EBADMSG;
	return err;
}

static int alauda_write(struct mtd_info *mtd, loff_t to, size_t len,
		size_t *retlen, const u_char *buf)
{
	struct alauda *al = mtd->priv;
	int err;

	if ((to & al->bytemask) || (len & al->bytemask))
		return -EINVAL;

	*retlen = len;
	while (len) {
		u32 page = (to >> al->card->pageshift) & al->pagemask;
		u8 oob[16] = {	'h', 'e', 'l', 'l', 'o', 0xff, 0xff, 0xff,
				0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};

		/* don't write to bad blocks */
		if (page == 0) {
			err = alauda_isbad(mtd, to);
			if (err) {
				return -EIO;
			}
		}
		nand_calculate_ecc(mtd, buf, &oob[13]);
		nand_calculate_ecc(mtd, buf+256, &oob[8]);

		err = alauda_write_page(mtd, to, (void*)buf, oob);
		if (err)
			return err;

		buf += mtd->writesize;
		to += mtd->writesize;
		len -= mtd->writesize;
	}
	return 0;
}

static int __alauda_erase(struct mtd_info *mtd, struct erase_info *instr)
{
	struct alauda *al = mtd->priv;
	u32 ofs = instr->addr;
	u32 len = instr->len;
	int err;

	if ((ofs & al->blockmask) || (len & al->blockmask))
		return -EINVAL;

	while (len) {
		/* don't erase bad blocks */
		err = alauda_isbad(mtd, ofs);
		if (err > 0)
			err = -EIO;
		if (err < 0)
			return err;

		err = alauda_erase_block(mtd, ofs);
		if (err < 0)
			return err;

		ofs += mtd->erasesize;
		len -= mtd->erasesize;
	}
	return 0;
}

static int alauda_erase(struct mtd_info *mtd, struct erase_info *instr)
{
	int err;

	err = __alauda_erase(mtd, instr);
	instr->state = err ? MTD_ERASE_FAILED : MTD_ERASE_DONE;
	mtd_erase_callback(instr);
	return err;
}

static int alauda_init_media(struct alauda *al)
{
	u8 buf[4], *b0=buf, *b1=buf+1;
	struct alauda_card *card;
	struct mtd_info *mtd;
	int err;

	mtd = kzalloc(sizeof(*mtd), GFP_KERNEL);
	if (!mtd)
		return -ENOMEM;

	for (;;) {
		err = alauda_get_media_status(al, buf);
		if (err < 0)
			goto error;
		if (*b0 & 0x10)
			break;
		msleep(20);
	}

	err = alauda_ack_media(al);
	if (err)
		goto error;

	msleep(10);

	err = alauda_get_media_status(al, buf);
	if (err < 0)
		goto error;

	if (*b0 != 0x14) {
		/* media not ready */
		err = -EIO;
		goto error;
	}
	err = alauda_get_media_signatures(al, buf);
	if (err < 0)
		goto error;

	card = get_card(*b1);
	if (!card) {
		printk(KERN_ERR"Alauda: unknown card id %02x\n", *b1);
		err = -EIO;
		goto error;
	}
	printk(KERN_INFO"pagesize=%x\nerasesize=%x\nsize=%xMiB\n",
			1<<card->pageshift, 1<<card->blockshift,
			1<<(card->chipshift-20));
	al->card = card;
	al->pagemask = (1 << (card->blockshift - card->pageshift)) - 1;
	al->bytemask = (1 << card->pageshift) - 1;
	al->blockmask = (1 << card->blockshift) - 1;

	mtd->name = "alauda";
	mtd->size = 1<<card->chipshift;
	mtd->erasesize = 1<<card->blockshift;
	mtd->writesize = 1<<card->pageshift;
	mtd->type = MTD_NANDFLASH;
	mtd->flags = MTD_CAP_NANDFLASH;
	mtd->read = alauda_read;
	mtd->write = alauda_write;
	mtd->erase = alauda_erase;
	mtd->block_isbad = alauda_isbad;
	mtd->priv = al;
	mtd->owner = THIS_MODULE;

	err = add_mtd_device(mtd);
	if (err) {
		err = -ENFILE;
		goto error;
	}

	al->mtd = mtd;
	alauda_reset(al); /* no clue whether this is necessary */
	return 0;
error:
	kfree(mtd);
	return err;
}

static int alauda_check_media(struct alauda *al)
{
	u8 buf[2], *b0 = buf, *b1 = buf+1;
	int err;

	err = alauda_get_media_status(al, buf);
	if (err < 0)
		return err;

	if ((*b1 & 0x01) == 0) {
		/* door open */
		return -EIO;
	}
	if ((*b0 & 0x80) || ((*b0 & 0x1F) == 0x10)) {
		/* no media ? */
		return -EIO;
	}
	if (*b0 & 0x08) {
		/* media change ? */
		return alauda_init_media(al);
	}
	return 0;
}

static int alauda_probe(struct usb_interface *interface,
		const struct usb_device_id *id)
{
	struct alauda *al;
	struct usb_host_interface *iface;
	struct usb_endpoint_descriptor *ep,
			*ep_in=NULL, *ep_out=NULL, *ep_wr=NULL;
	int i, err = -ENOMEM;

	al = kzalloc(2*sizeof(*al), GFP_KERNEL);
	if (!al)
		goto error;

	kref_init(&al->kref);
	usb_set_intfdata(interface, al);

	al->dev = usb_get_dev(interface_to_usbdev(interface));
	al->interface = interface;

	iface = interface->cur_altsetting;
	for (i = 0; i < iface->desc.bNumEndpoints; ++i) {
		ep = &iface->endpoint[i].desc;

		if (usb_endpoint_is_bulk_in(ep)) {
			ep_in = ep;
		} else if (usb_endpoint_is_bulk_out(ep)) {
			if (i==0)
				ep_wr = ep;
			else
				ep_out = ep;
		}
	}
	err = -EIO;
	if (!ep_wr || !ep_in || !ep_out)
		goto error;

	al->write_out = usb_sndbulkpipe(al->dev,
			usb_endpoint_num(ep_wr));
	al->bulk_in = usb_rcvbulkpipe(al->dev,
			usb_endpoint_num(ep_in));
	al->bulk_out = usb_sndbulkpipe(al->dev,
			usb_endpoint_num(ep_out));

	/* second device is identical up to now */
	memcpy(al+1, al, sizeof(*al));

	mutex_init(&al[0].card_mutex);
	mutex_init(&al[1].card_mutex);

	al[0].port = ALAUDA_PORT_XD;
	al[1].port = ALAUDA_PORT_SM;

	dev_info(&interface->dev, "alauda probed\n");
	alauda_check_media(al);
	alauda_check_media(al+1);

	return 0;

error:
	if (al)
		kref_put(&al->kref, alauda_delete);
	return err;
}

static void alauda_disconnect(struct usb_interface *interface)
{
	struct alauda *al;

	al = usb_get_intfdata(interface);
	usb_set_intfdata(interface, NULL);

	/* FIXME: prevent more I/O from starting */

	/* decrement our usage count */
	if (al)
		kref_put(&al->kref, alauda_delete);

	dev_info(&interface->dev, "alauda gone");
}

static struct usb_driver alauda_driver = {
	.name =		"alauda",
	.probe =	alauda_probe,
	.disconnect =	alauda_disconnect,
	.id_table =	alauda_table,
};

static int __init alauda_init(void)
{
	return usb_register(&alauda_driver);
}

static void __exit alauda_exit(void)
{
	usb_deregister(&alauda_driver);
}

module_init(alauda_init);
module_exit(alauda_exit);

MODULE_LICENSE("GPL");