linux_kernel/drivers/mtd/nand/cafe_nand.c

/*
 * Driver for One Laptop Per Child ‘CAFÉ’ controller, aka Marvell 88ALP01
 *
 * The data sheet for this device can be found at:
 *    http://wiki.laptop.org/go/Datasheets 
 *
 * Copyright © 2006 Red Hat, Inc.
 * Copyright © 2006 David Woodhouse <dwmw2@infradead.org>
 */

#define DEBUG

#include <linux/device.h>
#undef DEBUG
#include <linux/mtd/mtd.h>
#include <linux/mtd/nand.h>
#include <linux/mtd/partitions.h>
#include <linux/rslib.h>
#include <linux/pci.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/dma-mapping.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <asm/io.h>

#define CAFE_NAND_CTRL1		0x00
#define CAFE_NAND_CTRL2		0x04
#define CAFE_NAND_CTRL3		0x08
#define CAFE_NAND_STATUS	0x0c
#define CAFE_NAND_IRQ		0x10
#define CAFE_NAND_IRQ_MASK	0x14
#define CAFE_NAND_DATA_LEN	0x18
#define CAFE_NAND_ADDR1		0x1c
#define CAFE_NAND_ADDR2		0x20
#define CAFE_NAND_TIMING1	0x24
#define CAFE_NAND_TIMING2	0x28
#define CAFE_NAND_TIMING3	0x2c
#define CAFE_NAND_NONMEM	0x30
#define CAFE_NAND_ECC_RESULT	0x3C
#define CAFE_NAND_DMA_CTRL	0x40
#define CAFE_NAND_DMA_ADDR0	0x44
#define CAFE_NAND_DMA_ADDR1	0x48
#define CAFE_NAND_ECC_SYN01	0x50
#define CAFE_NAND_ECC_SYN23	0x54
#define CAFE_NAND_ECC_SYN45	0x58
#define CAFE_NAND_ECC_SYN67	0x5c
#define CAFE_NAND_READ_DATA	0x1000
#define CAFE_NAND_WRITE_DATA	0x2000

#define CAFE_GLOBAL_CTRL	0x3004
#define CAFE_GLOBAL_IRQ		0x3008
#define CAFE_GLOBAL_IRQ_MASK	0x300c
#define CAFE_NAND_RESET		0x3034

/* Missing from the datasheet: bit 19 of CTRL1 sets CE0 vs. CE1 */
#define CTRL1_CHIPSELECT	(1<<19)

struct cafe_priv {
	struct nand_chip nand;
	struct pci_dev *pdev;
	void __iomem *mmio;
	struct rs_control *rs;
	uint32_t ctl1;
	uint32_t ctl2;
	int datalen;
	int nr_data;
	int data_pos;
	int page_addr;
	dma_addr_t dmaaddr;
	unsigned char *dmabuf;
};

static int usedma = 1;
module_param(usedma, int, 0644);

static int skipbbt = 0;
module_param(skipbbt, int, 0644);

static int debug = 0;
module_param(debug, int, 0644);

static int regdebug = 0;
module_param(regdebug, int, 0644);

static int checkecc = 1;
module_param(checkecc, int, 0644);

static unsigned int numtimings;
static int timing[3];
module_param_array(timing, int, &numtimings, 0644);

static const char *part_probes[] = { "cmdlinepart", "RedBoot", NULL };

/* Hrm. Why isn't this already conditional on something in the struct device? */
#define cafe_dev_dbg(dev, args...) do { if (debug) dev_dbg(dev, ##args); } while(0)

/* Make it easier to switch to PIO if we need to */
#define cafe_readl(cafe, addr)			readl((cafe)->mmio + CAFE_##addr)
#define cafe_writel(cafe, datum, addr)		writel(datum, (cafe)->mmio + CAFE_##addr)

static int cafe_device_ready(struct mtd_info *mtd)
{
	struct nand_chip *chip = mtd_to_nand(mtd);
	struct cafe_priv *cafe = nand_get_controller_data(chip);
	int result = !!(cafe_readl(cafe, NAND_STATUS) & 0x40000000);
	uint32_t irqs = cafe_readl(cafe, NAND_IRQ);

	cafe_writel(cafe, irqs, NAND_IRQ);

	cafe_dev_dbg(&cafe->pdev->dev, "NAND device is%s ready, IRQ %x (%x) (%x,%x)\n",
		result?"":" not", irqs, cafe_readl(cafe, NAND_IRQ),
		cafe_readl(cafe, GLOBAL_IRQ), cafe_readl(cafe, GLOBAL_IRQ_MASK));

	return result;
}


static void cafe_write_buf(struct mtd_info *mtd, const uint8_t *buf, int len)
{
	struct nand_chip *chip = mtd_to_nand(mtd);
	struct cafe_priv *cafe = nand_get_controller_data(chip);

	if (usedma)
		memcpy(cafe->dmabuf + cafe->datalen, buf, len);
	else
		memcpy_toio(cafe->mmio + CAFE_NAND_WRITE_DATA + cafe->datalen, buf, len);

	cafe->datalen += len;

	cafe_dev_dbg(&cafe->pdev->dev, "Copy 0x%x bytes to write buffer. datalen 0x%x\n",
		len, cafe->datalen);
}

static void cafe_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
{
	struct nand_chip *chip = mtd_to_nand(mtd);
	struct cafe_priv *cafe = nand_get_controller_data(chip);

	if (usedma)
		memcpy(buf, cafe->dmabuf + cafe->datalen, len);
	else
		memcpy_fromio(buf, cafe->mmio + CAFE_NAND_READ_DATA + cafe->datalen, len);

	cafe_dev_dbg(&cafe->pdev->dev, "Copy 0x%x bytes from position 0x%x in read buffer.\n",
		  len, cafe->datalen);
	cafe->datalen += len;
}

static uint8_t cafe_read_byte(struct mtd_info *mtd)
{
	struct nand_chip *chip = mtd_to_nand(mtd);
	struct cafe_priv *cafe = nand_get_controller_data(chip);
	uint8_t d;

	cafe_read_buf(mtd, &d, 1);
	cafe_dev_dbg(&cafe->pdev->dev, "Read %02x\n", d);

	return d;
}

static void cafe_nand_cmdfunc(struct mtd_info *mtd, unsigned command,
			      int column, int page_addr)
{
	struct nand_chip *chip = mtd_to_nand(mtd);
	struct cafe_priv *cafe = nand_get_controller_data(chip);
	int adrbytes = 0;
	uint32_t ctl1;
	uint32_t doneint = 0x80000000;

	cafe_dev_dbg(&cafe->pdev->dev, "cmdfunc %02x, 0x%x, 0x%x\n",
		command, column, page_addr);

	if (command == NAND_CMD_ERASE2 || command == NAND_CMD_PAGEPROG) {
		/* Second half of a command we already calculated */
		cafe_writel(cafe, cafe->ctl2 | 0x100 | command, NAND_CTRL2);
		ctl1 = cafe->ctl1;
		cafe->ctl2 &= ~(1<<30);
		cafe_dev_dbg(&cafe->pdev->dev, "Continue command, ctl1 %08x, #data %d\n",
			  cafe->ctl1, cafe->nr_data);
		goto do_command;
	}
	/* Reset ECC engine */
	cafe_writel(cafe, 0, NAND_CTRL2);

	/* Emulate NAND_CMD_READOOB on large-page chips */
	if (mtd->writesize > 512 &&
	    command == NAND_CMD_READOOB) {
		column += mtd->writesize;
		command = NAND_CMD_READ0;
	}

	/* FIXME: Do we need to send read command before sending data
	   for small-page chips, to position the buffer correctly? */

	if (column != -1) {
		cafe_writel(cafe, column, NAND_ADDR1);
		adrbytes = 2;
		if (page_addr != -1)
			goto write_adr2;
	} else if (page_addr != -1) {
		cafe_writel(cafe, page_addr & 0xffff, NAND_ADDR1);
		page_addr >>= 16;
	write_adr2:
		cafe_writel(cafe, page_addr, NAND_ADDR2);
		adrbytes += 2;
		if (mtd->size > mtd->writesize << 16)
			adrbytes++;
	}

	cafe->data_pos = cafe->datalen = 0;

	/* Set command valid bit, mask in the chip select bit  */
	ctl1 = 0x80000000 | command | (cafe->ctl1 & CTRL1_CHIPSELECT);

	/* Set RD or WR bits as appropriate */
	if (command == NAND_CMD_READID || command == NAND_CMD_STATUS) {
		ctl1 |= (1<<26); /* rd */
		/* Always 5 bytes, for now */
		cafe->datalen = 4;
		/* And one address cycle -- even for STATUS, since the controller doesn't work without */
		adrbytes = 1;
	} else if (command == NAND_CMD_READ0 || command == NAND_CMD_READ1 ||
		   command == NAND_CMD_READOOB || command == NAND_CMD_RNDOUT) {
		ctl1 |= 1<<26; /* rd */
		/* For now, assume just read to end of page */
		cafe->datalen = mtd->writesize + mtd->oobsize - column;
	} else if (command == NAND_CMD_SEQIN)
		ctl1 |= 1<<25; /* wr */

	/* Set number of address bytes */
	if (adrbytes)
		ctl1 |= ((adrbytes-1)|8) << 27;

	if (command == NAND_CMD_SEQIN || command == NAND_CMD_ERASE1) {
		/* Ignore the first command of a pair; the hardware
		   deals with them both at once, later */
		cafe->ctl1 = ctl1;
		cafe_dev_dbg(&cafe->pdev->dev, "Setup for delayed command, ctl1 %08x, dlen %x\n",
			  cafe->ctl1, cafe->datalen);
		return;
	}
	/* RNDOUT and READ0 commands need a following byte */
	if (command == NAND_CMD_RNDOUT)
		cafe_writel(cafe, cafe->ctl2 | 0x100 | NAND_CMD_RNDOUTSTART, NAND_CTRL2);
	else if (command == NAND_CMD_READ0 && mtd->writesize > 512)
		cafe_writel(cafe, cafe->ctl2 | 0x100 | NAND_CMD_READSTART, NAND_CTRL2);

 do_command:
	cafe_dev_dbg(&cafe->pdev->dev, "dlen %x, ctl1 %x, ctl2 %x\n",
		cafe->datalen, ctl1, cafe_readl(cafe, NAND_CTRL2));

	/* NB: The datasheet lies -- we really should be subtracting 1 here */
	cafe_writel(cafe, cafe->datalen, NAND_DATA_LEN);
	cafe_writel(cafe, 0x90000000, NAND_IRQ);
	if (usedma && (ctl1 & (3<<25))) {
		uint32_t dmactl = 0xc0000000 + cafe->datalen;
		/* If WR or RD bits set, set up DMA */
		if (ctl1 & (1<<26)) {
			/* It's a read */
			dmactl |= (1<<29);
			/* ... so it's done when the DMA is done, not just
			   the command. */
			doneint = 0x10000000;
		}
		cafe_writel(cafe, dmactl, NAND_DMA_CTRL);
	}
	cafe->datalen = 0;

	if (unlikely(regdebug)) {
		int i;
		printk("About to write command %08x to register 0\n", ctl1);
		for (i=4; i< 0x5c; i+=4)
			printk("Register %x: %08x\n", i, readl(cafe->mmio + i));
	}

	cafe_writel(cafe, ctl1, NAND_CTRL1);
	/* Apply this short delay always to ensure that we do wait tWB in
	 * any case on any machine. */
	ndelay(100);

	if (1) {
		int c;
		uint32_t irqs;

		for (c = 500000; c != 0; c--) {
			irqs = cafe_readl(cafe, NAND_IRQ);
			if (irqs & doneint)
				break;
			udelay(1);
			if (!(c % 100000))
				cafe_dev_dbg(&cafe->pdev->dev, "Wait for ready, IRQ %x\n", irqs);
			cpu_relax();
		}
		cafe_writel(cafe, doneint, NAND_IRQ);
		cafe_dev_dbg(&cafe->pdev->dev, "Command %x completed after %d usec, irqs %x (%x)\n",
			     command, 500000-c, irqs, cafe_readl(cafe, NAND_IRQ));
	}

	WARN_ON(cafe->ctl2 & (1<<30));

	switch (command) {

	case NAND_CMD_CACHEDPROG:
	case NAND_CMD_PAGEPROG:
	case NAND_CMD_ERASE1:
	case NAND_CMD_ERASE2:
	case NAND_CMD_SEQIN:
	case NAND_CMD_RNDIN:
	case NAND_CMD_STATUS:
	case NAND_CMD_RNDOUT:
		cafe_writel(cafe, cafe->ctl2, NAND_CTRL2);
		return;
	}
	nand_wait_ready(mtd);
	cafe_writel(cafe, cafe->ctl2, NAND_CTRL2);
}

static void cafe_select_chip(struct mtd_info *mtd, int chipnr)
{
	struct nand_chip *chip = mtd_to_nand(mtd);
	struct cafe_priv *cafe = nand_get_controller_data(chip);

	cafe_dev_dbg(&cafe->pdev->dev, "select_chip %d\n", chipnr);

	/* Mask the appropriate bit into the stored value of ctl1
	   which will be used by cafe_nand_cmdfunc() */
	if (chipnr)
		cafe->ctl1 |= CTRL1_CHIPSELECT;
	else
		cafe->ctl1 &= ~CTRL1_CHIPSELECT;
}

static irqreturn_t cafe_nand_interrupt(int irq, void *id)
{
	struct mtd_info *mtd = id;
	struct nand_chip *chip = mtd_to_nand(mtd);
	struct cafe_priv *cafe = nand_get_controller_data(chip);
	uint32_t irqs = cafe_readl(cafe, NAND_IRQ);
	cafe_writel(cafe, irqs & ~0x90000000, NAND_IRQ);
	if (!irqs)
		return IRQ_NONE;

	cafe_dev_dbg(&cafe->pdev->dev, "irq, bits %x (%x)\n", irqs, cafe_readl(cafe, NAND_IRQ));
	return IRQ_HANDLED;
}

static void cafe_nand_bug(struct mtd_info *mtd)
{
	BUG();
}

static int cafe_nand_write_oob(struct mtd_info *mtd,
			       struct nand_chip *chip, int page)
{
	int status = 0;

	chip->cmdfunc(mtd, NAND_CMD_SEQIN, mtd->writesize, page);
	chip->write_buf(mtd, chip->oob_poi, mtd->oobsize);
	chip->cmdfunc(mtd, NAND_CMD_PAGEPROG, -1, -1);
	status = chip->waitfunc(mtd, chip);

	return status & NAND_STATUS_FAIL ? -EIO : 0;
}

/* Don't use -- use nand_read_oob_std for now */
static int cafe_nand_read_oob(struct mtd_info *mtd, struct nand_chip *chip,
			      int page)
{
	chip->cmdfunc(mtd, NAND_CMD_READOOB, 0, page);
	chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
	return 0;
}
/**
 * cafe_nand_read_page_syndrome - [REPLACEABLE] hardware ecc syndrome based page read
 * @mtd:	mtd info structure
 * @chip:	nand chip info structure
 * @buf:	buffer to store read data
 * @oob_required:	caller expects OOB data read to chip->oob_poi
 *
 * The hw generator calculates the error syndrome automatically. Therefore
 * we need a special oob layout and handling.
 */
static int cafe_nand_read_page(struct mtd_info *mtd, struct nand_chip *chip,
			       uint8_t *buf, int oob_required, int page)
{
	struct cafe_priv *cafe = nand_get_controller_data(chip);
	unsigned int max_bitflips = 0;

	cafe_dev_dbg(&cafe->pdev->dev, "ECC result %08x SYN1,2 %08x\n",
		     cafe_readl(cafe, NAND_ECC_RESULT),
		     cafe_readl(cafe, NAND_ECC_SYN01));

	chip->read_buf(mtd, buf, mtd->writesize);
	chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);

	if (checkecc && cafe_readl(cafe, NAND_ECC_RESULT) & (1<<18)) {
		unsigned short syn[8], pat[4];
		int pos[4];
		u8 *oob = chip->oob_poi;
		int i, n;

		for (i=0; i<8; i+=2) {
			uint32_t tmp = cafe_readl(cafe, NAND_ECC_SYN01 + (i*2));
			syn[i] = cafe->rs->index_of[tmp & 0xfff];
			syn[i+1] = cafe->rs->index_of[(tmp >> 16) & 0xfff];
		}

		n = decode_rs16(cafe->rs, NULL, NULL, 1367, syn, 0, pos, 0,
		                pat);

		for (i = 0; i < n; i++) {
			int p = pos[i];

			/* The 12-bit symbols are mapped to bytes here */

			if (p > 1374) {
				/* out of range */
				n = -1374;
			} else if (p == 0) {
				/* high four bits do not correspond to data */
				if (pat[i] > 0xff)
					n = -2048;
				else
					buf[0] ^= pat[i];
			} else if (p == 1365) {
				buf[2047] ^= pat[i] >> 4;
				oob[0] ^= pat[i] << 4;
			} else if (p > 1365) {
				if ((p & 1) == 1) {
					oob[3*p/2 - 2048] ^= pat[i] >> 4;
					oob[3*p/2 - 2047] ^= pat[i] << 4;
				} else {
					oob[3*p/2 - 2049] ^= pat[i] >> 8;
					oob[3*p/2 - 2048] ^= pat[i];
				}
			} else if ((p & 1) == 1) {
				buf[3*p/2] ^= pat[i] >> 4;
				buf[3*p/2 + 1] ^= pat[i] << 4;
			} else {
				buf[3*p/2 - 1] ^= pat[i] >> 8;
				buf[3*p/2] ^= pat[i];
			}
		}

		if (n < 0) {
			dev_dbg(&cafe->pdev->dev, "Failed to correct ECC at %08x\n",
				cafe_readl(cafe, NAND_ADDR2) * 2048);
			for (i = 0; i < 0x5c; i += 4)
				printk("Register %x: %08x\n", i, readl(cafe->mmio + i));
			mtd->ecc_stats.failed++;
		} else {
			dev_dbg(&cafe->pdev->dev, "Corrected %d symbol errors\n", n);
			mtd->ecc_stats.corrected += n;
			max_bitflips = max_t(unsigned int, max_bitflips, n);
		}
	}

	return max_bitflips;
}

static struct nand_ecclayout cafe_oobinfo_2048 = {
	.eccbytes = 14,
	.eccpos = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13},
	.oobfree = {{14, 50}}
};

/* Ick. The BBT code really ought to be able to work this bit out
   for itself from the above, at least for the 2KiB case */
static uint8_t cafe_bbt_pattern_2048[] = { 'B', 'b', 't', '0' };
static uint8_t cafe_mirror_pattern_2048[] = { '1', 't', 'b', 'B' };

static uint8_t cafe_bbt_pattern_512[] = { 0xBB };
static uint8_t cafe_mirror_pattern_512[] = { 0xBC };


static struct nand_bbt_descr cafe_bbt_main_descr_2048 = {
	.options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
		| NAND_BBT_2BIT | NAND_BBT_VERSION,
	.offs =	14,
	.len = 4,
	.veroffs = 18,
	.maxblocks = 4,
	.pattern = cafe_bbt_pattern_2048
};

static struct nand_bbt_descr cafe_bbt_mirror_descr_2048 = {
	.options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
		| NAND_BBT_2BIT | NAND_BBT_VERSION,
	.offs =	14,
	.len = 4,
	.veroffs = 18,
	.maxblocks = 4,
	.pattern = cafe_mirror_pattern_2048
};

static struct nand_ecclayout cafe_oobinfo_512 = {
	.eccbytes = 14,
	.eccpos = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13},
	.oobfree = {{14, 2}}
};

static struct nand_bbt_descr cafe_bbt_main_descr_512 = {
	.options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
		| NAND_BBT_2BIT | NAND_BBT_VERSION,
	.offs =	14,
	.len = 1,
	.veroffs = 15,
	.maxblocks = 4,
	.pattern = cafe_bbt_pattern_512
};

static struct nand_bbt_descr cafe_bbt_mirror_descr_512 = {
	.options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
		| NAND_BBT_2BIT | NAND_BBT_VERSION,
	.offs =	14,
	.len = 1,
	.veroffs = 15,
	.maxblocks = 4,
	.pattern = cafe_mirror_pattern_512
};


static int cafe_nand_write_page_lowlevel(struct mtd_info *mtd,
					  struct nand_chip *chip,
					  const uint8_t *buf, int oob_required,
					  int page)
{
	struct cafe_priv *cafe = nand_get_controller_data(chip);

	chip->write_buf(mtd, buf, mtd->writesize);
	chip->write_buf(mtd, chip->oob_poi, mtd->oobsize);

	/* Set up ECC autogeneration */
	cafe->ctl2 |= (1<<30);

	return 0;
}

static int cafe_nand_block_bad(struct mtd_info *mtd, loff_t ofs, int getchip)
{
	return 0;
}

/* F_2[X]/(X**6+X+1)  */
static unsigned short gf64_mul(u8 a, u8 b)
{
	u8 c;
	unsigned int i;

	c = 0;
	for (i = 0; i < 6; i++) {
		if (a & 1)
			c ^= b;
		a >>= 1;
		b <<= 1;
		if ((b & 0x40) != 0)
			b ^= 0x43;
	}

	return c;
}

/* F_64[X]/(X**2+X+A**-1) with A the generator of F_64[X]  */
static u16 gf4096_mul(u16 a, u16 b)
{
	u8 ah, al, bh, bl, ch, cl;

	ah = a >> 6;
	al = a & 0x3f;
	bh = b >> 6;
	bl = b & 0x3f;

	ch = gf64_mul(ah ^ al, bh ^ bl) ^ gf64_mul(al, bl);
	cl = gf64_mul(gf64_mul(ah, bh), 0x21) ^ gf64_mul(al, bl);

	return (ch << 6) ^ cl;
}

static int cafe_mul(int x)
{
	if (x == 0)
		return 1;
	return gf4096_mul(x, 0xe01);
}

static int cafe_nand_probe(struct pci_dev *pdev,
				     const struct pci_device_id *ent)
{
	struct mtd_info *mtd;
	struct cafe_priv *cafe;
	uint32_t ctrl;
	int err = 0;
	int old_dma;
	struct nand_buffers *nbuf;

	/* Very old versions shared the same PCI ident for all three
	   functions on the chip. Verify the class too... */
	if ((pdev->class >> 8) != PCI_CLASS_MEMORY_FLASH)
		return -ENODEV;

	err = pci_enable_device(pdev);
	if (err)
		return err;

	pci_set_master(pdev);

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

	mtd = nand_to_mtd(&cafe->nand);
	mtd->dev.parent = &pdev->dev;
	nand_set_controller_data(&cafe->nand, cafe);

	cafe->pdev = pdev;
	cafe->mmio = pci_iomap(pdev, 0, 0);
	if (!cafe->mmio) {
		dev_warn(&pdev->dev, "failed to iomap\n");
		err = -ENOMEM;
		goto out_free_mtd;
	}

	cafe->rs = init_rs_non_canonical(12, &cafe_mul, 0, 1, 8);
	if (!cafe->rs) {
		err = -ENOMEM;
		goto out_ior;
	}

	cafe->nand.cmdfunc = cafe_nand_cmdfunc;
	cafe->nand.dev_ready = cafe_device_ready;
	cafe->nand.read_byte = cafe_read_byte;
	cafe->nand.read_buf = cafe_read_buf;
	cafe->nand.write_buf = cafe_write_buf;
	cafe->nand.select_chip = cafe_select_chip;

	cafe->nand.chip_delay = 0;

	/* Enable the following for a flash based bad block table */
	cafe->nand.bbt_options = NAND_BBT_USE_FLASH;
	cafe->nand.options = NAND_OWN_BUFFERS;

	if (skipbbt) {
		cafe->nand.options |= NAND_SKIP_BBTSCAN;
		cafe->nand.block_bad = cafe_nand_block_bad;
	}

	if (numtimings && numtimings != 3) {
		dev_warn(&cafe->pdev->dev, "%d timing register values ignored; precisely three are required\n", numtimings);
	}

	if (numtimings == 3) {
		cafe_dev_dbg(&cafe->pdev->dev, "Using provided timings (%08x %08x %08x)\n",
			     timing[0], timing[1], timing[2]);
	} else {
		timing[0] = cafe_readl(cafe, NAND_TIMING1);
		timing[1] = cafe_readl(cafe, NAND_TIMING2);
		timing[2] = cafe_readl(cafe, NAND_TIMING3);

		if (timing[0] | timing[1] | timing[2]) {
			cafe_dev_dbg(&cafe->pdev->dev, "Timing registers already set (%08x %08x %08x)\n",
				     timing[0], timing[1], timing[2]);
		} else {
			dev_warn(&cafe->pdev->dev, "Timing registers unset; using most conservative defaults\n");
			timing[0] = timing[1] = timing[2] = 0xffffffff;
		}
	}

	/* Start off by resetting the NAND controller completely */
	cafe_writel(cafe, 1, NAND_RESET);
	cafe_writel(cafe, 0, NAND_RESET);

	cafe_writel(cafe, timing[0], NAND_TIMING1);
	cafe_writel(cafe, timing[1], NAND_TIMING2);
	cafe_writel(cafe, timing[2], NAND_TIMING3);

	cafe_writel(cafe, 0xffffffff, NAND_IRQ_MASK);
	err = request_irq(pdev->irq, &cafe_nand_interrupt, IRQF_SHARED,
			  "CAFE NAND", mtd);
	if (err) {
		dev_warn(&pdev->dev, "Could not register IRQ %d\n", pdev->irq);
		goto out_ior;
	}

	/* Disable master reset, enable NAND clock */
	ctrl = cafe_readl(cafe, GLOBAL_CTRL);
	ctrl &= 0xffffeff0;
	ctrl |= 0x00007000;
	cafe_writel(cafe, ctrl | 0x05, GLOBAL_CTRL);
	cafe_writel(cafe, ctrl | 0x0a, GLOBAL_CTRL);
	cafe_writel(cafe, 0, NAND_DMA_CTRL);

	cafe_writel(cafe, 0x7006, GLOBAL_CTRL);
	cafe_writel(cafe, 0x700a, GLOBAL_CTRL);

	/* Enable NAND IRQ in global IRQ mask register */
	cafe_writel(cafe, 0x80000007, GLOBAL_IRQ_MASK);
	cafe_dev_dbg(&cafe->pdev->dev, "Control %x, IRQ mask %x\n",
		cafe_readl(cafe, GLOBAL_CTRL),
		cafe_readl(cafe, GLOBAL_IRQ_MASK));

	/* Do not use the DMA for the nand_scan_ident() */
	old_dma = usedma;
	usedma = 0;

	/* Scan to find existence of the device */
	if (nand_scan_ident(mtd, 2, NULL)) {
		err = -ENXIO;
		goto out_irq;
	}

	cafe->dmabuf = dma_alloc_coherent(&cafe->pdev->dev,
				2112 + sizeof(struct nand_buffers) +
				mtd->writesize + mtd->oobsize,
				&cafe->dmaaddr, GFP_KERNEL);
	if (!cafe->dmabuf) {
		err = -ENOMEM;
		goto out_irq;
	}
	cafe->nand.buffers = nbuf = (void *)cafe->dmabuf + 2112;

	/* Set up DMA address */
	cafe_writel(cafe, cafe->dmaaddr & 0xffffffff, NAND_DMA_ADDR0);
	if (sizeof(cafe->dmaaddr) > 4)
		/* Shift in two parts to shut the compiler up */
		cafe_writel(cafe, (cafe->dmaaddr >> 16) >> 16, NAND_DMA_ADDR1);
	else
		cafe_writel(cafe, 0, NAND_DMA_ADDR1);

	cafe_dev_dbg(&cafe->pdev->dev, "Set DMA address to %x (virt %p)\n",
		cafe_readl(cafe, NAND_DMA_ADDR0), cafe->dmabuf);

	/* this driver does not need the @ecccalc and @ecccode */
	nbuf->ecccalc = NULL;
	nbuf->ecccode = NULL;
	nbuf->databuf = (uint8_t *)(nbuf + 1);

	/* Restore the DMA flag */
	usedma = old_dma;

	cafe->ctl2 = 1<<27; /* Reed-Solomon ECC */
	if (mtd->writesize == 2048)
		cafe->ctl2 |= 1<<29; /* 2KiB page size */

	/* Set up ECC according to the type of chip we found */
	if (mtd->writesize == 2048) {
		cafe->nand.ecc.layout = &cafe_oobinfo_2048;
		cafe->nand.bbt_td = &cafe_bbt_main_descr_2048;
		cafe->nand.bbt_md = &cafe_bbt_mirror_descr_2048;
	} else if (mtd->writesize == 512) {
		cafe->nand.ecc.layout = &cafe_oobinfo_512;
		cafe->nand.bbt_td = &cafe_bbt_main_descr_512;
		cafe->nand.bbt_md = &cafe_bbt_mirror_descr_512;
	} else {
		printk(KERN_WARNING "Unexpected NAND flash writesize %d. Aborting\n",
		       mtd->writesize);
		goto out_free_dma;
	}
	cafe->nand.ecc.mode = NAND_ECC_HW_SYNDROME;
	cafe->nand.ecc.size = mtd->writesize;
	cafe->nand.ecc.bytes = 14;
	cafe->nand.ecc.strength = 4;
	cafe->nand.ecc.hwctl  = (void *)cafe_nand_bug;
	cafe->nand.ecc.calculate = (void *)cafe_nand_bug;
	cafe->nand.ecc.correct  = (void *)cafe_nand_bug;
	cafe->nand.ecc.write_page = cafe_nand_write_page_lowlevel;
	cafe->nand.ecc.write_oob = cafe_nand_write_oob;
	cafe->nand.ecc.read_page = cafe_nand_read_page;
	cafe->nand.ecc.read_oob = cafe_nand_read_oob;

	err = nand_scan_tail(mtd);
	if (err)
		goto out_free_dma;

	pci_set_drvdata(pdev, mtd);

	mtd->name = "cafe_nand";
	mtd_device_parse_register(mtd, part_probes, NULL, NULL, 0);

	goto out;

 out_free_dma:
	dma_free_coherent(&cafe->pdev->dev,
			2112 + sizeof(struct nand_buffers) +
			mtd->writesize + mtd->oobsize,
			cafe->dmabuf, cafe->dmaaddr);
 out_irq:
	/* Disable NAND IRQ in global IRQ mask register */
	cafe_writel(cafe, ~1 & cafe_readl(cafe, GLOBAL_IRQ_MASK), GLOBAL_IRQ_MASK);
	free_irq(pdev->irq, mtd);
 out_ior:
	pci_iounmap(pdev, cafe->mmio);
 out_free_mtd:
	kfree(cafe);
 out:
	return err;
}

static void cafe_nand_remove(struct pci_dev *pdev)
{
	struct mtd_info *mtd = pci_get_drvdata(pdev);
	struct nand_chip *chip = mtd_to_nand(mtd);
	struct cafe_priv *cafe = nand_get_controller_data(chip);

	/* Disable NAND IRQ in global IRQ mask register */
	cafe_writel(cafe, ~1 & cafe_readl(cafe, GLOBAL_IRQ_MASK), GLOBAL_IRQ_MASK);
	free_irq(pdev->irq, mtd);
	nand_release(mtd);
	free_rs(cafe->rs);
	pci_iounmap(pdev, cafe->mmio);
	dma_free_coherent(&cafe->pdev->dev,
			2112 + sizeof(struct nand_buffers) +
			mtd->writesize + mtd->oobsize,
			cafe->dmabuf, cafe->dmaaddr);
	kfree(cafe);
}

static const struct pci_device_id cafe_nand_tbl[] = {
	{ PCI_VENDOR_ID_MARVELL, PCI_DEVICE_ID_MARVELL_88ALP01_NAND,
	  PCI_ANY_ID, PCI_ANY_ID },
	{ }
};

MODULE_DEVICE_TABLE(pci, cafe_nand_tbl);

static int cafe_nand_resume(struct pci_dev *pdev)
{
	uint32_t ctrl;
	struct mtd_info *mtd = pci_get_drvdata(pdev);
	struct nand_chip *chip = mtd_to_nand(mtd);
	struct cafe_priv *cafe = nand_get_controller_data(chip);

       /* Start off by resetting the NAND controller completely */
	cafe_writel(cafe, 1, NAND_RESET);
	cafe_writel(cafe, 0, NAND_RESET);
	cafe_writel(cafe, 0xffffffff, NAND_IRQ_MASK);

	/* Restore timing configuration */
	cafe_writel(cafe, timing[0], NAND_TIMING1);
	cafe_writel(cafe, timing[1], NAND_TIMING2);
	cafe_writel(cafe, timing[2], NAND_TIMING3);

        /* Disable master reset, enable NAND clock */
	ctrl = cafe_readl(cafe, GLOBAL_CTRL);
	ctrl &= 0xffffeff0;
	ctrl |= 0x00007000;
	cafe_writel(cafe, ctrl | 0x05, GLOBAL_CTRL);
	cafe_writel(cafe, ctrl | 0x0a, GLOBAL_CTRL);
	cafe_writel(cafe, 0, NAND_DMA_CTRL);
	cafe_writel(cafe, 0x7006, GLOBAL_CTRL);
	cafe_writel(cafe, 0x700a, GLOBAL_CTRL);

	/* Set up DMA address */
	cafe_writel(cafe, cafe->dmaaddr & 0xffffffff, NAND_DMA_ADDR0);
	if (sizeof(cafe->dmaaddr) > 4)
	/* Shift in two parts to shut the compiler up */
		cafe_writel(cafe, (cafe->dmaaddr >> 16) >> 16, NAND_DMA_ADDR1);
	else
		cafe_writel(cafe, 0, NAND_DMA_ADDR1);

	/* Enable NAND IRQ in global IRQ mask register */
	cafe_writel(cafe, 0x80000007, GLOBAL_IRQ_MASK);
	return 0;
}

static struct pci_driver cafe_nand_pci_driver = {
	.name = "CAFÉ NAND",
	.id_table = cafe_nand_tbl,
	.probe = cafe_nand_probe,
	.remove = cafe_nand_remove,
	.resume = cafe_nand_resume,
};

module_pci_driver(cafe_nand_pci_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
MODULE_DESCRIPTION("NAND flash driver for OLPC CAFÉ chip");