/*
 * Driver for NAND support, Rick Bronson
 * borrowed heavily from:
 * (c) 1999 Machine Vision Holdings, Inc.
 * (c) 1999, 2000 David Woodhouse <dwmw2@infradead.org>
 */

#include "Board.h"
#include <stdlib.h>
#include "NandFlash.h"
#include "po_types.h"

#include "nand.h"
#include "nand_ids.h"
#include "jffs2.h"

#define ROUND_DOWN(value,boundary)      ((value) & (~((boundary)-1)))

/*
 * Definition of the out of band configuration structure
 */
struct nand_oob_config {
	int ecc_pos[6];		/* position of ECC bytes inside oob */
	int badblock_pos;	/* position of bad block flag inside oob -1 = inactive */
	int eccvalid_pos;	/* position of ECC valid flag inside oob -1 = inactive */
} oob_config = { {0}, 0, 0};

#define	NAND_DEBUG
#undef	PSYCHO_DEBUG

/* ****************** WARNING *********************
 * When ALLOW_ERASE_BAD_DEBUG is non-zero the erase command will
 * erase (or at least attempt to erase) blocks that are marked
 * bad. This can be very handy if you are _sure_ that the block
 * is OK, say because you marked a good block bad to test bad
 * block handling and you are done testing, or if you have
 * accidentally marked blocks bad.
 *
 * Erasing factory marked bad blocks is a _bad_ idea. If the
 * erase succeeds there is no reliable way to find them again,
 * and attempting to program or erase bad blocks can affect
 * the data in _other_ (good) blocks.
 */
#define	 ALLOW_ERASE_BAD_DEBUG 0

#undef CONFIG_MTD_NAND_ECC  /* enable ECC */
#undef CONFIG_MTD_NAND_ECC_JFFS2

/*
 * Function Prototypes
 */
static void nand_print(struct nand_chip *nand);
int nand_rw (struct nand_chip* nand, int cmd,
	    size_t start, size_t len,
	    size_t * retlen, u_char * buf);
int nand_erase(struct nand_chip* nand, size_t ofs, size_t len, int clean);
static int nand_read_ecc(struct nand_chip *nand, size_t start, size_t len,
		 size_t * retlen, u_char *buf, u_char *ecc_code);
static int nand_write_ecc (struct nand_chip* nand, size_t to, size_t len,
			   size_t * retlen, const u_char * buf, u_char * ecc_code);
static void nand_print_bad(struct nand_chip *nand);
static int nand_read_oob(struct nand_chip* nand, size_t ofs, size_t len,
		 size_t * retlen, u_char * buf);
static int nand_write_oob(struct nand_chip* nand, size_t ofs, size_t len,
		 size_t * retlen, const u_char * buf);
static int NanD_WaitReady(struct nand_chip *nand, int ale_wait);
#ifdef CONFIG_MTD_NAND_ECC
static int nand_correct_data (u_char *dat, u_char *read_ecc, u_char *calc_ecc);
static void nand_calculate_ecc (const u_char *dat, u_char *ecc_code);
#endif

struct nand_chip nand_dev_desc[CFG_MAX_NAND_DEVICE] = {{0}};

/* Current NAND Device	*/
int curr_device = -1;

/* ------------------------------------------------------------------------- */

/* returns 0 if block containing pos is OK:
 *		valid erase block and
 *		not marked bad, or no bad mark position is specified
 * returns 1 if marked bad or otherwise invalid
 */
int check_block(struct nand_chip* nand, unsigned long pos)
{
	int retlen;
	uint8_t oob_data;
	int page0 = pos & (-nand->erasesize);
	int page1 = page0 + nand->oobblock;
	int badpos = oob_config.badblock_pos;

	if (pos >= nand->totlen)
		return 1;

	if (badpos < 0)
		return 0;	/* no way to check, assume OK */

	/* Note - bad block marker can be on first or second page */
	if (nand_read_oob(nand, page0 + badpos, 1, (size_t *)&retlen, &oob_data) ||
	    oob_data != 0xff ||
	    nand_read_oob(nand, page1 + badpos, 1, (size_t *)&retlen, &oob_data) ||
	    oob_data != 0xff)
		return 1;

	return 0;
}

/* print bad blocks in NAND flash */
static void nand_print_bad(struct nand_chip* nand)
{
	unsigned long pos;

	for (pos = 0; pos < nand->totlen; pos += nand->erasesize) {
		if (check_block(nand, pos))
			printf(" 0x%8.8lx\n", pos);
	}
	puts("\n");
}

/* cmd: 0: NANDRW_WRITE			write, fail on bad block
 *	1: NANDRW_READ			read, fail on bad block
 *	2: NANDRW_WRITE | NANDRW_JFFS2	write, skip bad blocks
 *	3: NANDRW_READ | NANDRW_JFFS2	read, data all 0xff for bad blocks
 *      7: NANDRW_READ | NANDRW_JFFS2 | NANDRW_JFFS2_SKIP read, skip bad blocks
 */
int nand_rw (struct nand_chip* nand, int cmd,
	    size_t start, size_t len,
	    size_t * retlen, u_char * buf)
{
	int ret = 0, n, total = 0;
	char eccbuf[6];
	/* eblk (once set) is the start of the erase block containing the
	 * data being processed.
	 */
	unsigned long eblk = ~0;	/* force mismatch on first pass */
	unsigned long erasesize = nand->erasesize;

	while (len) {
		if ((start & (-erasesize)) != eblk) {
			/* have crossed into new erase block, deal with
			 * it if it is sure marked bad.
			 */
			eblk = start & (-erasesize); /* start of block */
			if (check_block(nand, eblk)) {
				if (cmd == (NANDRW_READ | NANDRW_JFFS2)) {
					while (len > 0 &&
					       start - eblk < erasesize) {
						*(buf++) = 0xff;
						++start;
						++total;
						--len;
					}
					continue;
				}
				else if (cmd == (NANDRW_READ | NANDRW_JFFS2 | NANDRW_JFFS2_SKIP)) {
					start += erasesize;
					continue;
				}
				else if (cmd == (NANDRW_WRITE | NANDRW_JFFS2)) {
					/* skip bad block */
					start += erasesize;
					continue;
				}
				else {
					ret = 1;
					break;
				}
			}
		}
		/* The ECC will not be calculated correctly if
		   less than 512 is written or read */
		/* Is request at least 512 bytes AND it starts on a proper boundry */
		if((start != ROUND_DOWN(start, 0x200)) || (len < 0x200))
			printf("Warning block writes should be at least 512 bytes and start on a 512 byte boundry\n");

		if (cmd & NANDRW_READ)
			ret = nand_read_ecc(nand, start,
					   min(len, eblk + erasesize - start),
					   (size_t *)&n, (u_char*)buf, (u_char *)eccbuf);
		else
			ret = nand_write_ecc(nand, start,
					   min(len, eblk + erasesize - start),
					   (size_t *)&n, (u_char*)buf, (u_char *)eccbuf);

		if (ret)
			break;

		start  += n;
		buf   += n;
		total += n;
		len   -= n;
	}
	if (retlen)
		*retlen = total;

	return ret;
}

static void nand_print(struct nand_chip *nand)
{
	if (nand->numchips > 1) {
		printf("%s at 0x%lx,\n"
		       "\t  %d chips %s, size %d MB, \n"
		       "\t  total size %ld MB, sector size %ld kB\n",
		       nand->name, nand->IO_ADDR, nand->numchips,
		       nand->chips_name, 1 << (nand->chipshift - 20),
		       nand->totlen >> 20, nand->erasesize >> 10);
	}
	else {
		printf("%s at 0x%lx (", nand->chips_name, nand->IO_ADDR);
//		print_size(nand->totlen, ", ");
//		print_size(nand->erasesize, " sector)\n");
	}
}

/* ------------------------------------------------------------------------- */

static int NanD_WaitReady(struct nand_chip *nand, int ale_wait)
{
	/* This is inline, to optimise the common case, where it's ready instantly */
	int ret = 0;

#ifdef NAND_NO_RB	/* in config file, shorter delays currently wrap accesses */
	if(ale_wait)
		NAND_WAIT_READY(nand);	/* do the worst case 25us wait */
	else
		udelay(10);
#else	/* has functional r/b signal */
	NAND_WAIT_READY(nand);
#endif
	return ret;
}

/* NanD_Command: Send a flash command to the flash chip */

static __inline int NanD_Command(struct nand_chip *nand, unsigned char command)
{
	unsigned long nandptr = nand->IO_ADDR;

	/* Assert the CLE (Command Latch Enable) line to the flash chip */
	NAND_CTL_SETCLE(nandptr);

	/* Send the command */
	WRITE_NAND_COMMAND(command, nandptr);

	/* Lower the CLE line */
	NAND_CTL_CLRCLE(nandptr);

#ifdef NAND_NO_RB
	if(command == NAND_CMD_RESET){
		u_char ret_val;
		NanD_Command(nand, NAND_CMD_STATUS);
		do{
			ret_val = READ_NAND(nandptr);/* wait till ready */
		} while((ret_val & 0x40) != 0x40);
	}
#endif
	return NanD_WaitReady(nand, 0);
}

/* NanD_Address: Set the current address for the flash chip */

static int NanD_Address(struct nand_chip *nand, int numbytes, unsigned long ofs)
{
	unsigned long nandptr;
	int i;

	nandptr = nand->IO_ADDR;

	/* Assert the ALE (Address Latch Enable) line to the flash chip */
	NAND_CTL_SETALE(nandptr);

	/* Send the address */
	/* Devices with 256-byte page are addressed as:
	 * Column (bits 0-7), Page (bits 8-15, 16-23, 24-31)
	 * there is no device on the market with page256
	 * and more than 24 bits.
	 * Devices with 512-byte page are addressed as:
	 * Column (bits 0-7), Page (bits 9-16, 17-24, 25-31)
	 * 25-31 is sent only if the chip support it.
	 * bit 8 changes the read command to be sent
	 * (NAND_CMD_READ0 or NAND_CMD_READ1).
	 */

	if (numbytes == ADDR_COLUMN || numbytes == ADDR_COLUMN_PAGE)
		WRITE_NAND_ADDRESS(ofs, nandptr);

	ofs = ofs >> nand->page_shift;

	if (numbytes == ADDR_PAGE || numbytes == ADDR_COLUMN_PAGE)
		for (i = 0; i < nand->pageadrlen; i++, ofs = ofs >> 8)
			WRITE_NAND_ADDRESS(ofs, nandptr);

	/* Lower the ALE line */
	NAND_CTL_CLRALE(nandptr);

	/* Wait for the chip to respond */
	return NanD_WaitReady(nand, 1);
}

/* NanD_SelectChip: Select a given flash chip within the current floor */

static __inline int NanD_SelectChip(struct nand_chip *nand, int chip)
{
	/* Wait for it to be ready */
	return NanD_WaitReady(nand, 0);
}

/* NanD_IdentChip: Identify a given NAND chip given {floor,chip} */

static int NanD_IdentChip(struct nand_chip *nand, int floor, int chip)
{
	int mfr, id, i;

	NAND_ENABLE_CE(nand);  /* set pin low */
	/* Reset the chip */
	if (NanD_Command(nand, NAND_CMD_RESET)) {
#ifdef NAND_DEBUG
		printf("NanD_Command (reset) for %d,%d returned true\n",
		       floor, chip);
#endif
		NAND_DISABLE_CE(nand);  /* set pin high */
		return 0;
	}

	/* Read the NAND chip ID: 1. Send ReadID command */
	if (NanD_Command(nand, NAND_CMD_READID)) {
#ifdef NAND_DEBUG
		printf("NanD_Command (ReadID) for %d,%d returned true\n",
		       floor, chip);
#endif
		NAND_DISABLE_CE(nand);  /* set pin high */
		return 0;
	}

	/* Read the NAND chip ID: 2. Send address byte zero */
	NanD_Address(nand, ADDR_COLUMN, 0);

	/* Read the manufacturer and device id codes from the device */

	mfr = READ_NAND(nand->IO_ADDR);

	id = READ_NAND(nand->IO_ADDR);

	NAND_DISABLE_CE(nand);  /* set pin high */
	/* No response - return failure */
	if (mfr == 0xff || mfr == 0) {
#ifdef NAND_DEBUG
		printf("NanD_Command (ReadID) got %d %d\n", mfr, id);
#endif
		return 0;
	}

	/* Check it's the same as the first chip we identified.
	 * M-Systems say that any given nand_chip device should only
	 * contain _one_ type of flash part, although that's not a
	 * hardware restriction. */
	if (nand->mfr) {
		if (nand->mfr == mfr && nand->id == id)
			return 1;	/* This is another the same the first */
		else
			printf("Flash chip at floor %d, chip %d is different:\n",
			       floor, chip);
	}

	/* Print and store the manufacturer and ID codes. */
	for (i = 0; nand_flash_ids[i].name != NULL; i++) {
		if (mfr == nand_flash_ids[i].manufacture_id &&
		    id == nand_flash_ids[i].model_id) {
#ifdef NAND_DEBUG
			printf("Flash chip found:\n\t Manufacturer ID: 0x%2.2X, "
			       "Chip ID: 0x%2.2X (%s)\n", mfr, id,
			       nand_flash_ids[i].name);
#endif
			if (!nand->mfr) {
				nand->mfr = mfr;
				nand->id = id;
				nand->chipshift =
				    nand_flash_ids[i].chipshift;
				nand->page256 = nand_flash_ids[i].page256;
				nand->eccsize = 256;
				if (nand->page256) {
					nand->oobblock = 256;
					nand->oobsize = 8;
					nand->page_shift = 8;
				} else {
					nand->oobblock = 512;
					nand->oobsize = 16;
					nand->page_shift = 9;
				}
				nand->pageadrlen =
				    nand_flash_ids[i].pageadrlen;
				nand->erasesize =
				    nand_flash_ids[i].erasesize;
				nand->chips_name =
				    nand_flash_ids[i].name;
				return 1;
			}
			return 0;
		}
	}


#ifdef NAND_DEBUG
	/* We haven't fully identified the chip. Print as much as we know. */
	printf("Unknown flash chip found: %2.2X %2.2X\n",
	       id, mfr);
#endif

	return 0;
}

/* NanD_ScanChips: Find all NAND chips present in a nand_chip, and identify them */

static void NanD_ScanChips(struct nand_chip *nand)
{
	int floor, chip;
	int numchips[NAND_MAX_FLOORS];
	int maxchips = NAND_MAX_CHIPS;
	int ret = 1;

	nand->numchips = 0;
	nand->mfr = 0;
	nand->id = 0;


	/* For each floor, find the number of valid chips it contains */
	for (floor = 0; floor < NAND_MAX_FLOORS; floor++) {
		ret = 1;
		numchips[floor] = 0;
		for (chip = 0; chip < maxchips && ret != 0; chip++) {

			ret = NanD_IdentChip(nand, floor, chip);
			if (ret) {
				numchips[floor]++;
				nand->numchips++;
			}
		}
	}

	/* If there are none at all that we recognise, bail */
	if (!nand->numchips) {
#ifdef NAND_DEBUG
		puts ("No NAND flash chips recognised.\n");
#endif
		return;
	}

	/* Allocate an array to hold the information for each chip */
	nand->chips = malloc(sizeof(struct Nand) * nand->numchips);
	if (!nand->chips) {
		puts ("No memory for allocating chip info structures\n");
		return;
	}