/*
 * Common Flash Interface support:
 *   Intel Extended Vendor Command Set (ID 0x0001)
 *
 * (C) 2000 Red Hat. GPL'd
 *
 * $Id: cfi_cmdset_0001.c,v 1.114 2003/03/18 12:28:40 dwmw2 Exp $
 *
 * 
 * 10/10/2000	Nicolas Pitre <nico@cam.org>
 * 	- completely revamped method functions so they are aware and
 * 	  independent of the flash geometry (buswidth, interleave, etc.)
 * 	- scalability vs code size is completely set at compile-time
 * 	  (see include/linux/mtd/cfi.h for selection)
 *	- optimized write buffer method
 * 02/05/2002	Christopher Hoover <ch@hpl.hp.com>/<ch@murgatroid.com>
 *	- reworked lock/unlock/erase support for var size flash
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <asm/io.h>
#include <asm/byteorder.h>

#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/mtd/map.h>
#include <linux/mtd/cfi.h>
#include <linux/mtd/compatmac.h>

// debugging, turns off buffer write mode #define FORCE_WORD_WRITE

static int cfi_intelext_read (struct mtd_info *, loff_t, size_t, size_t *, u_char *);
static int cfi_intelext_read_user_prot_reg (struct mtd_info *, loff_t, size_t, size_t *, u_char *);
static int cfi_intelext_read_fact_prot_reg (struct mtd_info *, loff_t, size_t, size_t *, u_char *);
static int cfi_intelext_write_words(struct mtd_info *, loff_t, size_t, size_t *, const u_char *);
static int cfi_intelext_write_buffers(struct mtd_info *, loff_t, size_t, size_t *, const u_char *);
static int cfi_intelext_erase_varsize(struct mtd_info *, struct erase_info *);
static void cfi_intelext_sync (struct mtd_info *);
static int cfi_intelext_lock(struct mtd_info *mtd, loff_t ofs, size_t len);
static int cfi_intelext_unlock(struct mtd_info *mtd, loff_t ofs, size_t len);
static int cfi_intelext_suspend (struct mtd_info *);
static void cfi_intelext_resume (struct mtd_info *);

static void cfi_intelext_destroy(struct mtd_info *);

struct mtd_info *cfi_cmdset_0001(struct map_info *, int);

static struct mtd_info *cfi_intelext_setup (struct map_info *);

static int do_point (struct mtd_info *mtd, loff_t from, size_t len,
		     size_t *retlen, u_char **mtdbuf);
static void do_unpoint (struct mtd_info *mtd, u_char *addr, loff_t from,
			size_t len);

static struct mtd_chip_driver cfi_intelext_chipdrv = {
	probe: NULL, /* Not usable directly */
	destroy: cfi_intelext_destroy,
	name: "cfi_cmdset_0001",
	module: THIS_MODULE
};

/* #define DEBUG_LOCK_BITS */
/* #define DEBUG_CFI_FEATURES */

#ifdef DEBUG_CFI_FEATURES
static void cfi_tell_features(struct cfi_pri_intelext *extp)
{
	int i;
	printk("  Feature/Command Support: %4.4X\n", extp->FeatureSupport);
	printk("     - Chip Erase:         %s\n", extp->FeatureSupport&1?"supported":"unsupported");
	printk("     - Suspend Erase:      %s\n", extp->FeatureSupport&2?"supported":"unsupported");
	printk("     - Suspend Program:    %s\n", extp->FeatureSupport&4?"supported":"unsupported");
	printk("     - Legacy Lock/Unlock: %s\n", extp->FeatureSupport&8?"supported":"unsupported");
	printk("     - Queued Erase:       %s\n", extp->FeatureSupport&16?"supported":"unsupported");
	printk("     - Instant block lock: %s\n", extp->FeatureSupport&32?"supported":"unsupported");
	printk("     - Protection Bits:    %s\n", extp->FeatureSupport&64?"supported":"unsupported");
	printk("     - Page-mode read:     %s\n", extp->FeatureSupport&128?"supported":"unsupported");
	printk("     - Synchronous read:   %s\n", extp->FeatureSupport&256?"supported":"unsupported");
	for (i=9; i<32; i++) {
		if (extp->FeatureSupport & (1<<i)) 
			printk("     - Unknown Bit %X:      supported\n", i);
	}
	
	printk("  Supported functions after Suspend: %2.2X\n", extp->SuspendCmdSupport);
	printk("     - Program after Erase Suspend: %s\n", extp->SuspendCmdSupport&1?"supported":"unsupported");
	for (i=1; i<8; i++) {
		if (extp->SuspendCmdSupport & (1<<i))
			printk("     - Unknown Bit %X:               supported\n", i);
	}
	
	printk("  Block Status Register Mask: %4.4X\n", extp->BlkStatusRegMask);
	printk("     - Lock Bit Active:      %s\n", extp->BlkStatusRegMask&1?"yes":"no");
	printk("     - Valid Bit Active:     %s\n", extp->BlkStatusRegMask&2?"yes":"no");
	for (i=2; i<16; i++) {
		if (extp->BlkStatusRegMask & (1<<i))
			printk("     - Unknown Bit %X Active: yes\n",i);
	}
	
	printk("  Vcc Logic Supply Optimum Program/Erase Voltage: %d.%d V\n", 
	       extp->VccOptimal >> 8, extp->VccOptimal & 0xf);
	if (extp->VppOptimal)
		printk("  Vpp Programming Supply Optimum Program/Erase Voltage: %d.%d V\n", 
		       extp->VppOptimal >> 8, extp->VppOptimal & 0xf);
}
#endif

/* This routine is made available to other mtd code via
 * inter_module_register.  It must only be accessed through
 * inter_module_get which will bump the use count of this module.  The
 * addresses passed back in cfi are valid as long as the use count of
 * this module is non-zero, i.e. between inter_module_get and
 * inter_module_put.  Keith Owens <kaos@ocs.com.au> 29 Oct 2000.
 */
struct mtd_info *cfi_cmdset_0001(struct map_info *map, int primary)
{
	struct cfi_private *cfi = map->fldrv_priv;
	int i;
	__u32 base = cfi->chips[0].start;

	if (cfi->cfi_mode == CFI_MODE_CFI) {
		/* 
		 * It's a real CFI chip, not one for which the probe
		 * routine faked a CFI structure. So we read the feature
		 * table from it.
		 */
		__u16 adr = primary?cfi->cfiq->P_ADR:cfi->cfiq->A_ADR;
		struct cfi_pri_intelext *extp;
		int ofs_factor = cfi->interleave * cfi->device_type;

		//printk(" Intel/Sharp Extended Query Table at 0x%4.4X\n", adr);
		if (!adr)
			return NULL;

		/* Switch it into Query Mode */
		cfi_send_gen_cmd(0x98, 0x55, base, map, cfi, cfi->device_type, NULL);

		extp = kmalloc(sizeof(*extp), GFP_KERNEL);
		if (!extp) {
			printk(KERN_ERR "Failed to allocate memory\n");
			return NULL;
		}
		
		/* Read in the Extended Query Table */
		for (i=0; i<sizeof(*extp); i++) {
			((unsigned char *)extp)[i] = 
				cfi_read_query(map, (base+((adr+i)*ofs_factor)));
		}
		
		if (extp->MajorVersion != '1' || 
		    (extp->MinorVersion < '0' || extp->MinorVersion > '3')) {
			printk(KERN_WARNING "  Unknown IntelExt Extended Query "
			       "version %c.%c.\n",  extp->MajorVersion,
			       extp->MinorVersion);
			kfree(extp);
			return NULL;
		}
		
		/* Do some byteswapping if necessary */
		extp->FeatureSupport = le32_to_cpu(extp->FeatureSupport);
		extp->BlkStatusRegMask = le16_to_cpu(extp->BlkStatusRegMask);
		extp->ProtRegAddr = le16_to_cpu(extp->ProtRegAddr);
			
#ifdef DEBUG_CFI_FEATURES
		/* Tell the user about it in lots of lovely detail */
		cfi_tell_features(extp);
#endif	

		if(extp->SuspendCmdSupport & 1) {
//#define CMDSET0001_DISABLE_ERASE_SUSPEND_ON_WRITE
#ifdef CMDSET0001_DISABLE_ERASE_SUSPEND_ON_WRITE
/* Some Intel Strata Flash prior to FPO revision C has bugs in this area */ 
			printk(KERN_WARNING "cfi_cmdset_0001: Suspend "
			       "erase on write disabled.\n");
			extp->SuspendCmdSupport &= ~1;
#else
			printk(KERN_NOTICE "cfi_cmdset_0001: Erase suspend on write enabled\n");
#endif
		}
		/* Install our own private info structure */
		cfi->cmdset_priv = extp;	
	}

	for (i=0; i< cfi->numchips; i++) {
		cfi->chips[i].word_write_time = 1<<cfi->cfiq->WordWriteTimeoutTyp;
		cfi->chips[i].buffer_write_time = 1<<cfi->cfiq->BufWriteTimeoutTyp;
		cfi->chips[i].erase_time = 1<<cfi->cfiq->BlockEraseTimeoutTyp;
		cfi->chips[i].ref_point_counter = 0;
	}		

	map->fldrv = &cfi_intelext_chipdrv;
	
	/* Make sure it's in read mode */
	cfi_send_gen_cmd(0xff, 0x55, base, map, cfi, cfi->device_type, NULL);
	return cfi_intelext_setup(map);
}

static struct mtd_info *cfi_intelext_setup(struct map_info *map)
{
	struct cfi_private *cfi = map->fldrv_priv;
	struct mtd_info *mtd;
	unsigned long offset = 0;
	int i,j;
	unsigned long devsize = (1<<cfi->cfiq->DevSize) * cfi->interleave;

	mtd = kmalloc(sizeof(*mtd), GFP_KERNEL);
	//printk(KERN_DEBUG "number of CFI chips: %d\n", cfi->numchips);

	if (!mtd) {
		printk(KERN_ERR "Failed to allocate memory for MTD device\n");
		goto setup_err;
	}

	memset(mtd, 0, sizeof(*mtd));
	mtd->priv = map;
	mtd->type = MTD_NORFLASH;
	mtd->size = devsize * cfi->numchips;

	mtd->numeraseregions = cfi->cfiq->NumEraseRegions * cfi->numchips;
	mtd->eraseregions = kmalloc(sizeof(struct mtd_erase_region_info) 
			* mtd->numeraseregions, GFP_KERNEL);
	if (!mtd->eraseregions) { 
		printk(KERN_ERR "Failed to allocate memory for MTD erase region info\n");
		goto setup_err;
	}
	
	for (i=0; i<cfi->cfiq->NumEraseRegions; i++) {
		unsigned long ernum, ersize;
		ersize = ((cfi->cfiq->EraseRegionInfo[i] >> 8) & ~0xff) * cfi->interleave;
		ernum = (cfi->cfiq->EraseRegionInfo[i] & 0xffff) + 1;

		if (mtd->erasesize < ersize) {
			mtd->erasesize = ersize;
		}
		for (j=0; j<cfi->numchips; j++) {
			mtd->eraseregions[(j*cfi->cfiq->NumEraseRegions)+i].offset = (j*devsize)+offset;
			mtd->eraseregions[(j*cfi->cfiq->NumEraseRegions)+i].erasesize = ersize;
			mtd->eraseregions[(j*cfi->cfiq->NumEraseRegions)+i].numblocks = ernum;
		}
		offset += (ersize * ernum);
	}

	if (offset != devsize) {
		/* Argh */
		printk(KERN_WARNING "Sum of regions (%lx) != total size of set of interleaved chips (%lx)\n", offset, devsize);
		goto setup_err;
	}

	for (i=0; i<mtd->numeraseregions;i++){
		printk(KERN_DEBUG "%d: offset=0x%x,size=0x%x,blocks=%d\n",
		       i,mtd->eraseregions[i].offset,
		       mtd->eraseregions[i].erasesize,
		       mtd->eraseregions[i].numblocks);
	}

	/* Also select the correct geometry setup too */ 
	mtd->erase = cfi_intelext_erase_varsize;
	mtd->read = cfi_intelext_read;

	if(map->point && map->unpoint){
		mtd->point = do_point;
		mtd->unpoint = do_unpoint;
	}

#ifndef FORCE_WORD_WRITE
	if ( cfi->cfiq->BufWriteTimeoutTyp ) {
		printk("Using buffer write method\n" );
		mtd->write = cfi_intelext_write_buffers;
	} else {
#else
	{
#endif
		printk("Using word write method\n" );
		mtd->write = cfi_intelext_write_words;
	}
	mtd->read_user_prot_reg = cfi_intelext_read_user_prot_reg;
	mtd->read_fact_prot_reg = cfi_intelext_read_fact_prot_reg;
	mtd->sync = cfi_intelext_sync;
	mtd->lock = cfi_intelext_lock;
	mtd->unlock = cfi_intelext_unlock;
	mtd->suspend = cfi_intelext_suspend;
	mtd->resume = cfi_intelext_resume;
	mtd->flags = MTD_CAP_NORFLASH;
	map->fldrv = &cfi_intelext_chipdrv;
	MOD_INC_USE_COUNT;
	mtd->name = map->name;
	return mtd;

 setup_err:
	if(mtd) {
		if(mtd->eraseregions)
			kfree(mtd->eraseregions);
		kfree(mtd);
	}
	kfree(cfi->cmdset_priv);
	kfree(cfi->cfiq);
	return NULL;
}

static int do_point_onechip (struct map_info *map,  struct flchip *chip, loff_t adr, size_t len)
{
	cfi_word status, status_OK;
	unsigned long timeo;
	DECLARE_WAITQUEUE(wait, current);
	unsigned long cmd_addr;
	struct cfi_private *cfi = map->fldrv_priv;

	adr += chip->start;

	/* Ensure cmd read/writes are aligned. */ 
	cmd_addr = adr & ~(CFIDEV_BUSWIDTH-1); 

	/* Let's determine this according to the interleave only once */
	status_OK = CMD(0x80);

	timeo = jiffies + HZ;
 retry:
	spin_lock(chip->mutex);

	/* Check that the chip's ready to talk to us.
	 * If it's in FL_ERASING state, suspend it and make it talk now.
	 */
	switch (chip->state) {

	case FL_READY:
	case FL_POINT:
		break;

	case FL_CFI_QUERY:
	case FL_JEDEC_QUERY:
		cfi_write(map, CMD(0x70), cmd_addr);
		chip->state = FL_STATUS;

	case FL_STATUS:
		status = cfi_read(map, cmd_addr);
		if ((status & status_OK) == status_OK) {
			cfi_write(map, CMD(0xff), cmd_addr);
			chip->state = FL_READY;
			break;
		}
		
		/* Urgh. Chip not yet ready to talk to us. */
		if (time_after(jiffies, timeo)) {
			spin_unlock(chip->mutex);
			printk(KERN_ERR "waiting for chip to be ready timed out in read. WSM status = %llx\n", (__u64)status);
			return -EIO;
		}

		/* Latency issues. Drop the lock, wait a while and retry */
		spin_unlock(chip->mutex);
		cfi_udelay(1);
		goto retry;

	default:
		/* Stick ourselves on a wait queue to be woken when
		   someone changes the status */
		set_current_state(TASK_UNINTERRUPTIBLE);
		add_wait_queue(&chip->wq, &wait);
		spin_unlock(chip->mutex);
		schedule();
		remove_wait_queue(&chip->wq, &wait);
		timeo = jiffies + HZ;
		goto retry;
	}

	chip->state = FL_POINT;
	chip->ref_point_counter++;
	spin_unlock(chip->mutex);
	return 0;
}
static int do_point (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char **mtdbuf)
{
	struct map_info *map = mtd->priv;
	struct cfi_private *cfi = map->fldrv_priv;
	unsigned long ofs;
	int chipnum;
	int ret = 0;

	if (from + len > mtd->size)
		return -EINVAL;
	
	*mtdbuf = map->point(map, from, len);
	if(*mtdbuf == NULL)
		return -EINVAL; /* can not point this region */
	*retlen = 0;

	/* Now lock the chip(s) to POINT state */

	/* ofs: offset within the first chip that the first read should start */
	chipnum = (from >> cfi->chipshift);
	ofs = from - (chipnum <<  cfi->chipshift);

	while (len) {
		unsigned long thislen;

		if (chipnum >= cfi->numchips)
			break;

		if ((len + ofs -1) >> cfi->chipshift)
			thislen = (1<<cfi->chipshift) - ofs;
		else
			thislen = len;

		ret = do_point_onechip(map, &cfi->chips[chipnum], ofs, thislen);
		if (ret)
			break;

		*retlen += thislen;
		len -= thislen;
		
		ofs = 0;
		chipnum++;
	}
	return 0;
}

static void do_unpoint (struct mtd_info *mtd, u_char *addr, loff_t from, size_t len)
{
	struct map_info *map = mtd->priv;
	struct cfi_private *cfi = map->fldrv_priv;
	unsigned long ofs;
	int chipnum;

	map->unpoint(map, addr, from, len);
	/* Now unlock the chip(s) POINT state */

	/* ofs: offset within the first chip that the first read should start */
	chipnum = (from >> cfi->chipshift);
	ofs = from - (chipnum <<  cfi->chipshift);

	while (len) {
		unsigned long thislen;
		struct flchip *chip;

		chip = &cfi->chips[chipnum];
		if (chipnum >= cfi->numchips)
			break;

		if ((len + ofs -1) >> cfi->chipshift)
			thislen = (1<<cfi->chipshift) - ofs;
		else
			thislen = len;

		spin_lock(chip->mutex);
		if(chip->state == FL_POINT){
			chip->ref_point_counter--;
			if(chip->ref_point_counter == 0)
				chip->state = FL_READY;
		} else
			printk("Warning: unpoint called on non pointed region\n"); /* Should this give an error? */
		wake_up(&chip->wq);
		spin_unlock(chip->mutex);

		len -= thislen;
		ofs = 0;
		chipnum++;
	}
}

static inline int do_read_onechip(struct map_info *map, struct flchip *chip, loff_t adr, size_t len, u_char *buf)
{
	cfi_word status, status_OK;
	unsigned long timeo;
	DECLARE_WAITQUEUE(wait, current);
	int suspended = 0;
	unsigned long cmd_addr;
	struct cfi_private *cfi = map->fldrv_priv;

	adr += chip->start;

	/* Ensure cmd read/writes are aligned. */ 
	cmd_addr = adr & ~(CFIDEV_BUSWIDTH-1); 

	/* Let's determine this according to the interleave only once */
	status_OK = CMD(0x80);

	timeo = jiffies + HZ;
 retry:
	spin_lock(chip->mutex);

	/* Check that the chip's ready to talk to us.
	 * If it's in FL_ERASING state, suspend it and make it talk now.
	 */
	switch (chip->state) {
	case FL_ERASING:
		if (!cfi->cmdset_priv ||
		    !(((struct cfi_pri_intelext *)cfi->cmdset_priv)->FeatureSupport & 2))
			goto sleep; /* We don't support erase suspend */
		
		cfi_write (map, CMD(0xb0), cmd_addr);
		/* If the flash has finished erasing, then 'erase suspend'
		 * appears to make some (28F320) flash devices switch to
		 * 'read' mode.  Make sure that we switch to 'read status'
		 * mode so we get the right data. --rmk
		 */
		cfi_write(map, CMD(0x70), cmd_addr);
		chip->oldstate = FL_ERASING;
		chip->state = FL_ERASE_SUSPENDING;
		//		printk("Erase suspending at 0x%lx\n", cmd_addr);
		for (;;) {
			status = cfi_read(map, cmd_addr);
			if ((status & status_OK) == status_OK)
				break;
			
			if (time_after(jiffies, timeo)) {
				/* Urgh */
				cfi_write(map, CMD(0xd0), cmd_addr);
				/* make sure we're in 'read status' mode */
				cfi_write(map, CMD(0x70), cmd_addr);
				chip->state = FL_ERASING;
				spin_unlock(chip->mutex);
				printk(KERN_ERR "Chip not ready after erase "
				       "suspended: status = 0x%llx\n", (__u64)status);
				return -EIO;
			}
			
			spin_unlock(chip->mutex);
			cfi_udelay(1);
			spin_lock(chip->mutex);
		}
		
		suspended = 1;
		cfi_write(map, CMD(0xff), cmd_addr);
		chip->state = FL_READY;
		break;
	
#if 0
	case FL_WRITING:
		/* Not quite yet */
#endif

	case FL_READY:
	case FL_POINT:
		break;

	case FL_CFI_QUERY:
	case FL_JEDEC_QUERY:
		cfi_write(map, CMD(0x70), cmd_addr);
		chip->state = FL_STATUS;

	case FL_STATUS:
		status = cfi_read(map, cmd_addr);
		if ((status & status_OK) == status_OK) {
			cfi_write(map, CMD(0xff), cmd_addr);
			chip->state = FL_READY;
			break;
		}
		
		/* Urgh. Chip not yet ready to talk to us. */
		if (time_after(jiffies, timeo)) {
			spin_unlock(chip->mutex);
			printk(KERN_ERR "waiting for chip to be ready timed out in read. WSM status = %llx\n", (__u64)status);
			return -EIO;
		}

		/* Latency issues. Drop the lock, wait a while and retry */
		spin_unlock(chip->mutex);
		cfi_udelay(1);
		goto retry;

	default:
	sleep:
		/* Stick ourselves on a wait queue to be woken when
		   someone changes the status */
		set_current_state(TASK_UNINTERRUPTIBLE);
		add_wait_queue(&chip->wq, &wait);
		spin_unlock(chip->mutex);
		schedule();
		remove_wait_queue(&chip->wq, &wait);
		timeo = jiffies + HZ;
		goto retry;
	}

	map->copy_from(map, buf, adr, len);

	if (suspended) {
		chip->state = chip->oldstate;
		/* What if one interleaved chip has finished and the 
		   other hasn't? The old code would leave the finished
		   one in READY mode. That's bad, and caused -EROFS 
		   errors to be returned from do_erase_oneblock because
		   that's the only bit it checked for at the time.
		   As the state machine appears to explicitly allow 
		   sending the 0x70 (Read Status) command to an erasing
		   chip and expecting it to be ignored, that's what we 
		   do. */
		cfi_write(map, CMD(0xd0), cmd_addr);
		cfi_write(map, CMD(0x70), cmd_addr);		
	}

	wake_up(&chip->wq);
	spin_unlock(chip->mutex);
	return 0;
}

static int cfi_intelext_read (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf)
{
	struct map_info *map = mtd->priv;
	struct cfi_private *cfi = map->fldrv_priv;
	unsigned long ofs;
	int chipnum;
	int ret = 0;

	/* ofs: offset within the first chip that the first read should start */
	chipnum = (from >> cfi->chipshift);
	ofs = from - (chipnum <<  cfi->chipshift);

	*retlen = 0;

	while (len) {
		unsigned long thislen;

		if (chipnum >= cfi->numchips)
			break;

		if ((len + ofs -1) >> cfi->chipshift)
			thislen = (1<<cfi->chipshift) - ofs;
		else
			thislen = len;

		ret = do_read_onechip(map, &cfi->chips[chipnum], ofs, thislen, buf);
		if (ret)
			break;

		*retlen += thislen;
		len -= thislen;
		buf += thislen;
		
		ofs = 0;
		chipnum++;
	}
	return ret;
}

static int cfi_intelext_read_prot_reg (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf, int base_offst, int reg_sz)
{
	struct map_info *map = mtd->priv;
	struct cfi_private *cfi = map->fldrv_priv;
	struct cfi_pri_intelext *extp=cfi->cmdset_priv;
	int ofs_factor = cfi->interleave * cfi->device_type;
	int   count=len;
	struct flchip *chip;
	int chip_num,offst;
	unsigned long timeo;
	DECLARE_WAITQUEUE(wait, current);

	chip=0;
	/* Calculate which chip & protection register offset we need */
	chip_num=((unsigned int)from/reg_sz);
	offst=from-(reg_sz*chip_num)+base_offst;

	while(count){
		
		if(chip_num>=cfi->numchips)
			goto out;

		/* Make sure that the chip is in the right state */

		timeo = jiffies + HZ;
		chip=&cfi->chips[chip_num];
	retry:		
		spin_lock(chip->mutex);
	
		switch (chip->state) {
		case FL_READY:
		case FL_STATUS:
		case FL_CFI_QUERY:
		case FL_JEDEC_QUERY:
			break;
		
		default:
				/* Stick ourselves on a wait queue to be woken when
				   someone changes the status */
			set_current_state(TASK_UNINTERRUPTIBLE);
			add_wait_queue(&chip->wq, &wait);
			spin_unlock(chip->mutex);
			schedule();
			remove_wait_queue(&chip->wq, &wait);
			timeo = jiffies + HZ;
			goto retry;
		}
			
		/* Now read the data required from this flash */
       
		cfi_send_gen_cmd(0x90, 0x55,chip->start, map, cfi, cfi->device_type, NULL);
		while(count && ((offst-base_offst)<reg_sz)){
			*buf=map->read8(map,(chip->start+((extp->ProtRegAddr+1)*ofs_factor)+offst));
			buf++;
			offst++;
			count--;
		}
	       
		chip->state=FL_CFI_QUERY;
		spin_unlock(chip->mutex);
		/* Move on to the next chip */
		chip_num++;
		offst=base_offst;
	
	}
	
 out:	
	wake_up(&chip->wq);
	return len-count;
}
	
static int cfi_intelext_read_user_prot_reg (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf)
{
	struct map_info *map = mtd->priv;
	struct cfi_private *cfi = map->fldrv_priv;
	struct cfi_pri_intelext *extp=cfi->cmdset_priv;
	int base_offst,reg_sz;
	
	/* Check that we actually have some protection registers */
	if(!(extp->FeatureSupport&64)){
		printk(KERN_WARNING "%s: This flash device has no protection data to read!\n",map->name);
		return 0;
	}

	base_offst=(1<<extp->FactProtRegSize);
	reg_sz=(1<<extp->UserProtRegSize);

	return cfi_intelext_read_prot_reg(mtd, from, len, retlen, buf, base_offst, reg_sz);
}

static int cfi_intelext_read_fact_prot_reg (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf)
{
	struct map_info *map = mtd->priv;
	struct cfi_private *cfi = map->fldrv_priv;
	struct cfi_pri_intelext *extp=cfi->cmdset_priv;
	int base_offst,reg_sz;
	
	/* Check that we actually have some protection registers */
	if(!(extp->FeatureSupport&64)){
		printk(KERN_WARNING "%s: This flash device has no protection data to read!\n",map->name);
		return 0;
	}

	base_offst=0;
	reg_sz=(1<<extp->FactProtRegSize);

	return cfi_intelext_read_prot_reg(mtd, from, len, retlen, buf, base_offst, reg_sz);
}


static int do_write_oneword(struct map_info *map, struct flchip *chip, unsigned long adr, cfi_word datum)
{
	struct cfi_private *cfi = map->fldrv_priv;
	struct cfi_pri_intelext *extp = cfi->cmdset_priv;
	cfi_word status, status_OK;
	unsigned long timeo;
	DECLARE_WAITQUEUE(wait, current);
	int z, suspended=0, ret=0;

	adr += chip->start;

	/* Let's determine this according to the interleave only once */
	status_OK = CMD(0x80);

	timeo = jiffies + HZ;
 retry:
	spin_lock(chip->mutex);

	/* Check that the chip's ready to talk to us.
	 * Later, we can actually think about interrupting it
	 * if it's in FL_ERASING state.
	 * Not just yet, though.
	 */
	switch (chip->state) {
	case FL_READY:
		break;
		
	case FL_CFI_QUERY:
	case FL_JEDEC_QUERY:
		cfi_write(map, CMD(0x70), adr);
		chip->state = FL_STATUS;

	case FL_STATUS:
		status = cfi_read(map, adr);
		if ((status & status_OK) == status_OK)
			break;
		
		/* Urgh. Chip not yet ready to talk to us. */
		if (time_after(jiffies, timeo)) {
			spin_unlock(chip->mutex);
			printk(KERN_ERR "waiting for chip to be ready timed out in read\n");
			return -EIO;
		}

		/* Latency issues. Drop the lock, wait a while and retry */
		spin_unlock(chip->mutex);
		cfi_udelay(1);
		goto retry;

	case FL_ERASING:
		if (!extp || 
		    !((extp->FeatureSupport & 2) && (extp->SuspendCmdSupport & 1)))
			goto sleep; /* We don't support erase suspend */
		
		cfi_write (map, CMD(0xb0), adr);

		/* If the flash has finished erasing, then 'erase suspend'
		 * appears to make some (28F320) flash devices switch to
		 * 'read' mode.  Make sure that we switch to 'read status'
		 * mode so we get the right data. --rmk
		 */
		cfi_write(map, CMD(0x70), adr);
		chip->oldstate = FL_ERASING;
		chip->state = FL_ERASE_SUSPENDING;
		for (;;) {
			status = cfi_read(map, adr);
			if ((status & status_OK) == status_OK)
				break;
			
			if (time_after(jiffies, timeo)) {
				/* Urgh */
				cfi_write(map, CMD(0xd0), adr);
				/* make sure we're in 'read status' mode */
				cfi_write(map, CMD(0x70), adr);
				chip->state = FL_ERASING;
				spin_unlock(chip->mutex);
				printk(KERN_ERR "Chip not ready after erase "
				       "suspended: status = 0x%x\n", status);
				return -EIO;
			}
			
			spin_unlock(chip->mutex);
			cfi_udelay(1);
			spin_lock(chip->mutex);
		}
		suspended = 1;
		chip->state = FL_STATUS;
		break;

	default:
	sleep:
		/* Stick ourselves on a wait queue to be woken when
		   someone changes the status */
		set_current_state(TASK_UNINTERRUPTIBLE);
		add_wait_queue(&chip->wq, &wait);
		spin_unlock(chip->mutex);
		schedule();
		remove_wait_queue(&chip->wq, &wait);
		timeo = jiffies + HZ;
		goto retry;
	}

	ENABLE_VPP(map);
	cfi_write(map, CMD(0x40), adr);
	cfi_write(map, datum, adr);
	chip->state = FL_WRITING;

	spin_unlock(chip->mutex);
	cfi_udelay(chip->word_write_time);
	spin_lock(chip->mutex);

	timeo = jiffies + (HZ/2);
	z = 0;
	for (;;) {
		if (chip->state != FL_WRITING) {
			/* Someone's suspended the write. Sleep */
			set_current_state(TASK_UNINTERRUPTIBLE);
			add_wait_queue(&chip->wq, &wait);
			spin_unlock(chip->mutex);
			schedule();
			remove_wait_queue(&chip->wq, &wait);
			timeo = jiffies + (HZ / 2); /* FIXME */
			spin_lock(chip->mutex);
			continue;
		}

		status = cfi_read(map, adr);
		if ((status & status_OK) == status_OK)
			break;
		
		/* OK Still waiting */
		if (time_after(jiffies, timeo)) {
			chip->state = FL_STATUS;
			DISABLE_VPP(map);
			printk(KERN_ERR "waiting for chip to be ready timed out in word write\n");
			ret = -EIO;
			goto out;
		}

		/* Latency issues. Drop the lock, wait a while and retry */
		spin_unlock(chip->mutex);
		z++;
		cfi_udelay(1);
		spin_lock(chip->mutex);
	}
	if (!z) {
		chip->word_write_time--;
		if (!chip->word_write_time)
			chip->word_write_time++;
	}
	if (z > 1) 
		chip->word_write_time++;

	/* Done and happy. */
	chip->state = FL_STATUS;
	/* check for lock bit */
	if (status & CMD(0x02)) {
		/* clear status */
		cfi_write(map, CMD(0x50), adr);
		/* put back into read status register mode */
		cfi_write(map, CMD(0x70), adr);
		ret = -EROFS;
		goto out;
	}
 out:
	if (suspended) {
		chip->state = chip->oldstate;
		/* What if one interleaved chip has finished and the 
		   other hasn't? The old code would leave the finished
		   one in READY mode. That's bad, and caused -EROFS 
		   errors to be returned from do_erase_oneblock because
		   that's the only bit it checked for at the time.
		   As the state machine appears to explicitly allow 
		   sending the 0x70 (Read Status) command to an erasing
		   chip and expecting it to be ignored, that's what we 
		   do. */
		cfi_write(map, CMD(0xd0), adr);
		cfi_write(map, CMD(0x70), adr);		
	} else
		DISABLE_VPP(map); /* must not clear the VPP if there is a suspended erase to be resumed */

	wake_up(&chip->wq);
	spin_unlock(chip->mutex);
	return ret;
}


static int cfi_intelext_write_words (struct mtd_info *mtd, loff_t to , size_t len, size_t *retlen, const u_char *buf)
{
	struct map_info *map = mtd->priv;
	struct cfi_private *cfi = map->fldrv_priv;
	int ret = 0;
	int chipnum;
	unsigned long ofs;

	*retlen = 0;
	if (!len)
		return 0;

	chipnum = to >> cfi->chipshift;
	ofs = to  - (chipnum << cfi->chipshift);

	/* If it's not bus-aligned, do the first byte write */
	if (ofs & (CFIDEV_BUSWIDTH-1)) {
		unsigned long bus_ofs = ofs & ~(CFIDEV_BUSWIDTH-1);
		int gap = ofs - bus_ofs;
		int i = 0, n = 0;
		u_char tmp_buf[8];
		cfi_word datum;

		while (gap--)
			tmp_buf[i++] = 0xff;
		while (len && i < CFIDEV_BUSWIDTH)
			tmp_buf[i++] = buf[n++], len--;
		while (i < CFIDEV_BUSWIDTH)
			tmp_buf[i++] = 0xff;

		if (cfi_buswidth_is_2()) {
			datum = *(__u16*)tmp_buf;
		} else if (cfi_buswidth_is_4()) {
			datum = *(__u32*)tmp_buf;
		} else if (cfi_buswidth_is_8()) {
			datum = *(__u64*)tmp_buf;
		} else {
			return -EINVAL;  /* should never happen, but be safe */
		}

		ret = do_write_oneword(map, &cfi->chips[chipnum],
					       bus_ofs, datum);
		if (ret) 
			return ret;
		
		ofs += n;
		buf += n;
		(*retlen) += n;

		if (ofs >> cfi->chipshift) {
			chipnum ++; 
			ofs = 0;
			if (chipnum == cfi->numchips)
				return 0;
		}
	}
	
	while(len >= CFIDEV_BUSWIDTH) {
		cfi_word datum;

		if (cfi_buswidth_is_1()) {
			datum = *(__u8*)buf;
		} else if (cfi_buswidth_is_2()) {
			datum = *(__u16*)buf;
		} else if (cfi_buswidth_is_4()) {
			datum = *(__u32*)buf;
		} else if (cfi_buswidth_is_8()) {
			datum = *(__u64*)buf;
		} else {
			return -EINVAL;
		}

		ret = do_write_oneword(map, &cfi->chips[chipnum],
				ofs, datum);
		if (ret)
			return ret;

		ofs += CFIDEV_BUSWIDTH;
		buf += CFIDEV_BUSWIDTH;
		(*retlen) += CFIDEV_BUSWIDTH;
		len -= CFIDEV_BUSWIDTH;

		if (ofs >> cfi->chipshift) {
			chipnum ++; 
			ofs = 0;
			if (chipnum == cfi->numchips)
				return 0;
		}
	}

	if (len & (CFIDEV_BUSWIDTH-1)) {
		int i = 0, n = 0;
		u_char tmp_buf[8];
		cfi_word datum;

		while (len--)
			tmp_buf[i++] = buf[n++];
		while (i < CFIDEV_BUSWIDTH)
			tmp_buf[i++] = 0xff;

		if (cfi_buswidth_is_2()) {
			datum = *(__u16*)tmp_buf;
		} else if (cfi_buswidth_is_4()) {
			datum = *(__u32*)tmp_buf;
		} else if (cfi_buswidth_is_8()) {
			datum = *(__u64*)tmp_buf;
		} else {
			return -EINVAL;  /* should never happen, but be safe */
		}

		ret = do_write_oneword(map, &cfi->chips[chipnum],
					       ofs, datum);
		if (ret) 
			return ret;
		
		(*retlen) += n;
	}

	return 0;
}


static inline int do_write_buffer(struct map_info *map, struct flchip *chip, 
				  unsigned long adr, const u_char *buf, int len)
{
	struct cfi_private *cfi = map->fldrv_priv;
	struct cfi_pri_intelext *extp = cfi->cmdset_priv;
	cfi_word status, status_OK;
	unsigned long cmd_adr, timeo;
	DECLARE_WAITQUEUE(wait, current);
	int wbufsize, z, suspended=0, ret=0;

	wbufsize = CFIDEV_INTERLEAVE << cfi->cfiq->MaxBufWriteSize;
	adr += chip->start;
	cmd_adr = adr & ~(wbufsize-1);
	
	/* Let's determine this according to the interleave only once */
	status_OK = CMD(0x80);

	timeo = jiffies + HZ;
 retry:
	spin_lock(chip->mutex);

	/* Check that the chip's ready to talk to us.
	 * Later, we can actually think about interrupting it
	 * if it's in FL_ERASING state.
	 * Not just yet, though.
	 */
	switch (chip->state) {
	case FL_READY:
	case FL_CFI_QUERY:
	case FL_JEDEC_QUERY:
		cfi_write(map, CMD(0x70), cmd_adr);
		chip->state = FL_STATUS;

	case FL_STATUS:
		status = cfi_read(map, cmd_adr);
		if ((status & status_OK) == status_OK)
			break;
		/* Urgh. Chip not yet ready to talk to us. */
		if (time_after(jiffies, timeo)) {
			spin_unlock(chip->mutex);
			printk(KERN_ERR "waiting for chip to be ready timed out in buffer write\n");
			return -EIO;
		}

		/* Latency issues. Drop the lock, wait a while and retry */
		spin_unlock(chip->mutex);
		cfi_udelay(1);
		goto retry;

	case FL_ERASING:
		if (!extp || 
		    !((extp->FeatureSupport & 2) && (extp->SuspendCmdSupport & 1)))
			goto sleep; /* We don't support erase suspend */
		
		cfi_write (map, CMD(0xb0), adr);

		/* If the flash has finished erasing, then 'erase suspend'
		 * appears to make some (28F320) flash devices switch to
		 * 'read' mode.  Make sure that we switch to 'read status'
		 * mode so we get the right data. --rmk
		 */
		cfi_write(map, CMD(0x70), adr);
		chip->oldstate = FL_ERASING;
		chip->state = FL_ERASE_SUSPENDING;
		for (;;) {
			status = cfi_read(map, adr);
			if ((status & status_OK) == status_OK)
				break;
			
			if (time_after(jiffies, timeo)) {
				/* Urgh */
				cfi_write(map, CMD(0xd0), adr);
				/* make sure we're in 'read status' mode */
				cfi_write(map, CMD(0x70), adr);
				chip->state = FL_ERASING;
				spin_unlock(chip->mutex);
				printk(KERN_ERR "Chip not ready after erase "
				       "suspended: status = 0x%x\n", status);
				return -EIO;
			}
			
			spin_unlock(chip->mutex);
			cfi_udelay(1);
			spin_lock(chip->mutex);
		}
		suspended = 1;
		chip->state = FL_STATUS;
		break;

	default:
	sleep:
		/* Stick ourselves on a wait queue to be woken when
		   someone changes the status */
		set_current_state(TASK_UNINTERRUPTIBLE);
		add_wait_queue(&chip->wq, &wait);
		spin_unlock(chip->mutex);
		schedule();
		remove_wait_queue(&chip->wq, &wait);
		timeo = jiffies + HZ;
		goto retry;
	}
	/* We know we're now in FL_STATUS mode, and 'status' is current */
	/* §4.8 of the 28FxxxJ3A datasheet says "Any time SR.4 and/or SR.5 is set
	   [...], the device will not accept any more Write to Buffer commands". 
	   So we must check here and reset those bits if they're set. Otherwise
	   we're just pissing in the wind */
	if (status & CMD(0x30)) {
		printk(KERN_WARNING "SR.4 or SR.5 bits set in buffer write (status %x). Clearing.\n", status);
		cfi_write(map, CMD(0x50), cmd_adr);
		cfi_write(map, CMD(0x70), cmd_adr);
	}
	ENABLE_VPP(map);
	chip->state = FL_WRITING_TO_BUFFER;

	z = 0;
	for (;;) {
		cfi_write(map, CMD(0xe8), cmd_adr);

		status = cfi_read(map, cmd_adr);
		if ((status & status_OK) == status_OK)
			break;

		spin_unlock(chip->mutex);
		cfi_udelay(1);
		spin_lock(chip->mutex);

		if (++z > 20) {
			/* Argh. Not ready for write to buffer */
			cfi_write(map, CMD(0x70), cmd_adr);
			chip->state = FL_STATUS;
			DISABLE_VPP(map);
			printk(KERN_ERR "Chip not ready for buffer write. Xstatus = %llx, status = %llx\n", (__u64)status, (__u64)cfi_read(map, cmd_adr));
			/* Odd. Clear status bits */
			cfi_write(map, CMD(0x50), cmd_adr);
			cfi_write(map, CMD(0x70), cmd_adr);
			ret = -EIO;
			goto out;
		}
	}

	/* Write length of data to come */
	cfi_write(map, CMD(len/CFIDEV_BUSWIDTH-1), cmd_adr );

	/* Write data */
	for (z = 0; z < len; z += CFIDEV_BUSWIDTH) {
		if (cfi_buswidth_is_1()) {
			map->write8 (map, *(__u8*)buf, adr+z);
			buf += sizeof(__u8);
		} else if (cfi_buswidth_is_2()) {
			map->write16 (map, *(__u16*)buf, adr+z);
			buf += sizeof(__u16);
		} else if (cfi_buswidth_is_4()) {
			map->write32 (map, *(__u32*)buf, adr+z);
			buf += sizeof(__u32);
		} else if (cfi_buswidth_is_8()) {
			map->write64 (map, *(__u64*)buf, adr+z);
			buf += sizeof(__u64);
		} else {
			DISABLE_VPP(map);
			ret = -EINVAL;
			goto out;
		}
	}
	/* GO GO GO */
	cfi_write(map, CMD(0xd0), cmd_adr);
	chip->state = FL_WRITING;

	spin_unlock(chip->mutex);
	cfi_udelay(chip->buffer_write_time);
	spin_lock(chip->mutex);

	timeo = jiffies + (HZ/2);
	z = 0;
	for (;;) {
		if (chip->state != FL_WRITING) {
			/* Someone's suspended the write. Sleep */
			set_current_state(TASK_UNINTERRUPTIBLE);
			add_wait_queue(&chip->wq, &wait);
			spin_unlock(chip->mutex);
			schedule();
			remove_wait_queue(&chip->wq, &wait);
			timeo = jiffies + (HZ / 2); /* FIXME */
			spin_lock(chip->mutex);
			continue;
		}

		status = cfi_read(map, cmd_adr);
		if ((status & status_OK) == status_OK)
			break;

		/* OK Still waiting */
		if (time_after(jiffies, timeo)) {
			chip->state = FL_STATUS;
			DISABLE_VPP(map);
			printk(KERN_ERR "waiting for chip to be ready timed out in bufwrite\n");
			ret = -EIO;
			goto out;
		}
		
		/* Latency issues. Drop the lock, wait a while and retry */
		spin_unlock(chip->mutex);
		cfi_udelay(1);
		z++;
		spin_lock(chip->mutex);
	}
	if (!z) {
		chip->buffer_write_time--;
		if (!chip->buffer_write_time)
			chip->buffer_write_time++;
	}
	if (z > 1) 
		chip->buffer_write_time++;

	/* Done and happy. */
	chip->state = FL_STATUS;
	/* check for lock bit */
	if (status & CMD(0x02)) {
		/* clear status */
		cfi_write(map, CMD(0x50), cmd_adr);
		/* put back into read status register mode */
		cfi_write(map, CMD(0x70), adr);
		ret = -EROFS;
		goto out;
	}
 out:
	if (suspended) {
		chip->state = chip->oldstate;
		/* What if one interleaved chip has finished and the 
		   other hasn't? The old code would leave the finished
		   one in READY mode. That's bad, and caused -EROFS 
		   errors to be returned from do_erase_oneblock because
		   that's the only bit it checked for at the time.
		   As the state machine appears to explicitly allow 
		   sending the 0x70 (Read Status) command to an erasing
		   chip and expecting it to be ignored, that's what we 
		   do. */
		cfi_write(map, CMD(0xd0), adr);
		cfi_write(map, CMD(0x70), adr);		
	} else
		DISABLE_VPP(map); /* must not clear the VPP if there is a suspended erase to be resumed */

	wake_up(&chip->wq);
	spin_unlock(chip->mutex);
	return ret;
}

static int cfi_intelext_write_buffers (struct mtd_info *mtd, loff_t to, 
				       size_t len, size_t *retlen, const u_char *buf)
{
	struct map_info *map = mtd->priv;
	struct cfi_private *cfi = map->fldrv_priv;
	int wbufsize = CFIDEV_INTERLEAVE << cfi->cfiq->MaxBufWriteSize;
	int ret = 0;
	int chipnum;
	unsigned long ofs;

	*retlen = 0;
	if (!len)
		return 0;

	chipnum = to >> cfi->chipshift;
	ofs = to  - (chipnum << cfi->chipshift);

	/* If it's not bus-aligned, do the first word write */
	if (ofs & (CFIDEV_BUSWIDTH-1)) {
		size_t local_len = (-ofs)&(CFIDEV_BUSWIDTH-1);
		if (local_len > len)
			local_len = len;
		ret = cfi_intelext_write_words(mtd, to, local_len,
					       retlen, buf);
		if (ret)
			return ret;
		ofs += local_len;
		buf += local_len;
		len -= local_len;

		if (ofs >> cfi->chipshift) {
			chipnum ++;
			ofs = 0;
			if (chipnum == cfi->numchips)
				return 0;
		}
	}

	/* Write buffer is worth it only if more than one word to write... */
	while(len > CFIDEV_BUSWIDTH) {
		/* We must not cross write block boundaries */
		int size = wbufsize - (ofs & (wbufsize-1));

		if (size > len)
			size = len & ~(CFIDEV_BUSWIDTH-1);
		ret = do_write_buffer(map, &cfi->chips[chipnum], 
				      ofs, buf, size);
		if (ret)
			return ret;

		ofs += size;
		buf += size;
		(*retlen) += size;
		len -= size;

		if (ofs >> cfi->chipshift) {
			chipnum ++; 
			ofs = 0;
			if (chipnum == cfi->numchips)
				return 0;
		}
	}

	/* ... and write the remaining bytes */
	if (len > 0) {
		size_t local_retlen;
		ret = cfi_intelext_write_words(mtd, ofs + (chipnum << cfi->chipshift),
					       len, &local_retlen, buf);
		if (ret)
			return ret;
		(*retlen) += local_retlen;
	}

	return 0;
}

typedef int (*varsize_frob_t)(struct map_info *map, struct flchip *chip,
			      unsigned long adr, void *thunk);

static int cfi_intelext_varsize_frob(struct mtd_info *mtd, varsize_frob_t frob,
				     loff_t ofs, size_t len, void *thunk)
{
	struct map_info *map = mtd->priv;
	struct cfi_private *cfi = map->fldrv_priv;
	unsigned long adr;
	int chipnum, ret = 0;
	int i, first;
	struct mtd_erase_region_info *regions = mtd->eraseregions;

	if (ofs > mtd->size)
		return -EINVAL;

	if ((len + ofs) > mtd->size)
		return -EINVAL;

	/* Check that both start and end of the requested erase are
	 * aligned with the erasesize at the appropriate addresses.
	 */

	i = 0;

	/* Skip all erase regions which are ended before the start of 
	   the requested erase. Actually, to save on the calculations,
	   we skip to the first erase region which starts after the
	   start of the requested erase, and then go back one.
	*/
	
	while (i < mtd->numeraseregions && ofs >= regions[i].offset)
	       i++;
	i--;

	/* OK, now i is pointing at the erase region in which this 
	   erase request starts. Check the start of the requested
	   erase range is aligned with the erase size which is in
	   effect here.
	*/

	if (ofs & (regions[i].erasesize-1))
		return -EINVAL;

	/* Remember the erase region we start on */
	first = i;

	/* Next, check that the end of the requested erase is aligned
	 * with the erase region at that address.
	 */

	while (i<mtd->numeraseregions && (ofs + len) >= regions[i].offset)
		i++;

	/* As before, drop back one to point at the region in which
	   the address actually falls
	*/
	i--;
	
	if ((ofs + len) & (regions[i].erasesize-1))
		return -EINVAL;

	chipnum = ofs >> cfi->chipshift;
	adr = ofs - (chipnum << cfi->chipshift);

	i=first;

	while(len) {
		ret = (*frob)(map, &cfi->chips[chipnum], adr, thunk);
		
		if (ret)
			return ret;

		adr += regions[i].erasesize;
		len -= regions[i].erasesize;

		if (adr % (1<< cfi->chipshift) == ((regions[i].offset + (regions[i].erasesize * regions[i].numblocks)) %( 1<< cfi->chipshift)))
			i++;

		if (adr >> cfi->chipshift) {
			adr = 0;
			chipnum++;
			
			if (chipnum >= cfi->numchips)
			break;
		}
	}

	return 0;
}


static int do_erase_oneblock(struct map_info *map, struct flchip *chip, unsigned long adr, void *thunk)
{
	struct cfi_private *cfi = map->fldrv_priv;
	cfi_word status, status_OK;
	unsigned long timeo;
	int retries = 3;
	DECLARE_WAITQUEUE(wait, current);
	int ret = 0;

	adr += chip->start;

	/* Let's determine this according to the interleave only once */
	status_OK = CMD(0x80);

	timeo = jiffies + HZ;
retry:
	spin_lock(chip->mutex);

	/* Check that the chip's ready to talk to us. */
	switch (chip->state) {
	case FL_CFI_QUERY:
	case FL_JEDEC_QUERY:
	case FL_READY:
		cfi_write(map, CMD(0x70), adr);
		chip->state = FL_STATUS;

	case FL_STATUS:
		status = cfi_read(map, adr);
		if ((status & status_OK) == status_OK)
			break;
		
		/* Urgh. Chip not yet ready to talk to us. */
		if (time_after(jiffies, timeo)) {
			spin_unlock(chip->mutex);
			printk(KERN_ERR "waiting for chip to be ready timed out in erase\n");
			return -EIO;
		}

		/* Latency issues. Drop the lock, wait a while and retry */
		spin_unlock(chip->mutex);
		cfi_udelay(1);
		goto retry;

	default:
		/* Stick ourselves on a wait queue to be woken when
		   someone changes the status */
		set_current_state(TASK_UNINTERRUPTIBLE);
		add_wait_queue(&chip->wq, &wait);
		spin_unlock(chip->mutex);
		schedule();
		remove_wait_queue(&chip->wq, &wait);
		timeo = jiffies + HZ;
		goto retry;
	}

	ENABLE_VPP(map);
	/* Clear the status register first */
	cfi_write(map, CMD(0x50), adr);

	/* Now erase */
	cfi_write(map, CMD(0x20), adr);
	cfi_write(map, CMD(0xD0), adr);
	chip->state = FL_ERASING;
	chip->oldstate = 0;

	spin_unlock(chip->mutex);
	set_current_state(TASK_UNINTERRUPTIBLE);
	schedule_timeout((chip->erase_time*HZ)/(2*1000));
	spin_lock(chip->mutex);

	/* FIXME. Use a timer to check this, and return immediately. */
	/* Once the state machine's known to be working I'll do that */

	timeo = jiffies + (HZ*20);
	for (;;) {
		if (chip->state != FL_ERASING) {
			/* Someone's suspended the erase. Sleep */
			set_current_state(TASK_UNINTERRUPTIBLE);
			add_wait_queue(&chip->wq, &wait);
			spin_unlock(chip->mutex);
			schedule();
			remove_wait_queue(&chip->wq, &wait);
			spin_lock(chip->mutex);
			continue;
		}
		if (chip->oldstate) {
			/* This erase was suspended and resumed.
			   Adjust the timeout */
			timeo = jiffies + (HZ*20); /* FIXME */
			chip->oldstate = 0;
		}

		status = cfi_read(map, adr);
		if ((status & status_OK) == status_OK)
			break;
		
		/* OK Still waiting */
		if (time_after(jiffies, timeo)) {
			cfi_write(map, CMD(0x70), adr);
			chip->state = FL_STATUS;
			printk(KERN_ERR "waiting for erase at %08lx to complete timed out. Xstatus = %llx, status = %llx.\n",
			       adr, (__u64)status, (__u64)cfi_read(map, adr));
			/* Clear status bits */
			cfi_write(map, CMD(0x50), adr);
			cfi_write(map, CMD(0x70), adr);
			DISABLE_VPP(map);
			spin_unlock(chip->mutex);
			return -EIO;
		}
		
		/* Latency issues. Drop the lock, wait a while and retry */
		spin_unlock(chip->mutex);
		set_current_state(TASK_UNINTERRUPTIBLE);
		schedule_timeout(1);
		spin_lock(chip->mutex);
	}
	
	DISABLE_VPP(map);
	ret = 0;

	/* We've broken this before. It doesn't hurt to be safe */
	cfi_write(map, CMD(0x70), adr);
	chip->state = FL_STATUS;
	status = cfi_read(map, adr);

	/* check for lock bit */
	if (status & CMD(0x3a)) {
		unsigned char chipstatus = status;
		if (status != CMD(status & 0xff)) {
			int i;
			for (i = 1; i<CFIDEV_INTERLEAVE; i++) {
				      chipstatus |= status >> (cfi->device_type * 8);
			}
			printk(KERN_WARNING "Status is not identical for all chips: 0x%llx. Merging to give 0x%02x\n", (__u64)status, chipstatus);
		}
		/* Reset the error bits */
		cfi_write(map, CMD(0x50), adr);
		cfi_write(map, CMD(0x70), adr);
		
		if ((chipstatus & 0x30) == 0x30) {
			printk(KERN_NOTICE "Chip reports improper command sequence: status 0x%llx\n", (__u64)status);
			ret = -EIO;
		} else if (chipstatus & 0x02) {
			/* Protection bit set */
			ret = -EROFS;
		} else if (chipstatus & 0x8) {
			/* Voltage */
			printk(KERN_WARNING "Chip reports voltage low on erase: status 0x%llx\n", (__u64)status);
			ret = -EIO;
		} else if (chipstatus & 0x20) {
			if (retries--) {
				printk(KERN_DEBUG "Chip erase failed at 0x%08lx: status 0x%llx. Retrying...\n", adr, (__u64)status);
				timeo = jiffies + HZ;
				chip->state = FL_STATUS;
				spin_unlock(chip->mutex);
				goto retry;
			}
			printk(KERN_DEBUG "Chip erase failed at 0x%08lx: status 0x%llx\n", adr, (__u64)status);
			ret = -EIO;
		}
	}

	wake_up(&chip->wq);
	spin_unlock(chip->mutex);
	return ret;
}

int cfi_intelext_erase_varsize(struct mtd_info *mtd, struct erase_info *instr)
{
	unsigned long ofs, len;
	int ret;

	ofs = instr->addr;
	len = instr->len;

	ret = cfi_intelext_varsize_frob(mtd, do_erase_oneblock, ofs, len, 0);
	if (ret)
		return ret;

	instr->state = MTD_ERASE_DONE;
	if (instr->callback)
		instr->callback(instr);
	
	return 0;
}

static void cfi_intelext_sync (struct mtd_info *mtd)
{
	struct map_info *map = mtd->priv;
	struct cfi_private *cfi = map->fldrv_priv;
	int i;
	struct flchip *chip;
	int ret = 0;
	DECLARE_WAITQUEUE(wait, current);

	for (i=0; !ret && i<cfi->numchips; i++) {
		chip = &cfi->chips[i];

	retry:
		spin_lock(chip->mutex);

		switch(chip->state) {
		case FL_READY:
		case FL_STATUS:
		case FL_CFI_QUERY:
		case FL_JEDEC_QUERY:
			chip->oldstate = chip->state;
			chip->state = FL_SYNCING;
			/* No need to wake_up() on this state change - 
			 * as the whole point is that nobody can do anything
			 * with the chip now anyway.
			 */
		case FL_SYNCING:
			spin_unlock(chip->mutex);
			break;

		default:
			/* Not an idle state */
			set_current_state(TASK_UNINTERRUPTIBLE);
			add_wait_queue(&chip->wq, &wait);
			
			spin_unlock(chip->mutex);
			schedule();
		        remove_wait_queue(&chip->wq, &wait);
			
			goto retry;
		}
	}

	/* Unlock the chips again */

	for (i--; i >=0; i--) {
		chip = &cfi->chips[i];

		spin_lock(chip->mutex);
		
		if (chip->state == FL_SYNCING) {
			chip->state = chip->oldstate;
			wake_up(&chip->wq);
		}
		spin_unlock(chip->mutex);
	}
}

#ifdef DEBUG_LOCK_BITS
static int do_printlockstatus_oneblock(struct map_info *map, struct flchip *chip, unsigned long adr, void *thunk)
{
	struct cfi_private *cfi = map->fldrv_priv;
	int ofs_factor = cfi->interleave * cfi->device_type;

	cfi_send_gen_cmd(0x90, 0x55, 0, map, cfi, cfi->device_type, NULL);
	printk(KERN_DEBUG "block status register for 0x%08lx is %x\n",
	       adr, cfi_read_query(map, adr+(2*ofs_factor)));
	cfi_send_gen_cmd(0xff, 0x55, 0, map, cfi, cfi->device_type, NULL);
	
	return 0;
}
#endif

#define DO_XXLOCK_ONEBLOCK_LOCK		((void *) 1)
#define DO_XXLOCK_ONEBLOCK_UNLOCK	((void *) 2)

static int do_xxlock_oneblock(struct map_info *map, struct flchip *chip, unsigned long adr, void *thunk)
{
	struct cfi_private *cfi = map->fldrv_priv;
	cfi_word status, status_OK;
	unsigned long timeo = jiffies + HZ;
	DECLARE_WAITQUEUE(wait, current);

	adr += chip->start;

	/* Let's determine this according to the interleave only once */
	status_OK = CMD(0x80);

	timeo = jiffies + HZ;
retry:
	spin_lock(chip->mutex);

	/* Check that the chip's ready to talk to us. */
	switch (chip->state) {
	case FL_CFI_QUERY:
	case FL_JEDEC_QUERY:
	case FL_READY:
		cfi_write(map, CMD(0x70), adr);
		chip->state = FL_STATUS;

	case FL_STATUS:
		status = cfi_read(map, adr);
		if ((status & status_OK) == status_OK)
			break;
		
		/* Urgh. Chip not yet ready to talk to us. */
		if (time_after(jiffies, timeo)) {
			spin_unlock(chip->mutex);
			printk(KERN_ERR "%s: waiting for chip to be ready timed out\n", __FUNCTION__);
			return -EIO;
		}

		/* Latency issues. Drop the lock, wait a while and retry */
		spin_unlock(chip->mutex);
		cfi_udelay(1);
		goto retry;

	default:
		/* Stick ourselves on a wait queue to be woken when
		   someone changes the status */
		set_current_state(TASK_UNINTERRUPTIBLE);
		add_wait_queue(&chip->wq, &wait);
		spin_unlock(chip->mutex);
		schedule();
		remove_wait_queue(&chip->wq, &wait);
		timeo = jiffies + HZ;
		goto retry;
	}

	ENABLE_VPP(map);
	cfi_write(map, CMD(0x60), adr);

	if (thunk == DO_XXLOCK_ONEBLOCK_LOCK) {
		cfi_write(map, CMD(0x01), adr);
		chip->state = FL_LOCKING;
	} else if (thunk == DO_XXLOCK_ONEBLOCK_UNLOCK) {
		cfi_write(map, CMD(0xD0), adr);
		chip->state = FL_UNLOCKING;
	} else
		BUG();

	spin_unlock(chip->mutex);
	schedule_timeout(HZ);
	spin_lock(chip->mutex);

	/* FIXME. Use a timer to check this, and return immediately. */
	/* Once the state machine's known to be working I'll do that */

	timeo = jiffies + (HZ*20);
	for (;;) {

		status = cfi_read(map, adr);
		if ((status & status_OK) == status_OK)
			break;
		
		/* OK Still waiting */
		if (time_after(jiffies, timeo)) {
			cfi_write(map, CMD(0x70), adr);
			chip->state = FL_STATUS;
			printk(KERN_ERR "waiting for unlock to complete timed out. Xstatus = %llx, status = %llx.\n", (__u64)status, (__u64)cfi_read(map, adr));
			DISABLE_VPP(map);
			spin_unlock(chip->mutex);
			return -EIO;
		}
		
		/* Latency issues. Drop the lock, wait a while and retry */
		spin_unlock(chip->mutex);
		cfi_udelay(1);
		spin_lock(chip->mutex);
	}
	
	/* Done and happy. */
	chip->state = FL_STATUS;
	DISABLE_VPP(map);
	wake_up(&chip->wq);
	spin_unlock(chip->mutex);
	return 0;
}

static int cfi_intelext_lock(struct mtd_info *mtd, loff_t ofs, size_t len)
{
	int ret;

#ifdef DEBUG_LOCK_BITS
	printk(KERN_DEBUG "%s: lock status before, ofs=0x%08llx, len=0x%08X\n",
	       __FUNCTION__, ofs, len);
	cfi_intelext_varsize_frob(mtd, do_printlockstatus_oneblock,
				  ofs, len, 0);
#endif

	ret = cfi_intelext_varsize_frob(mtd, do_xxlock_oneblock, 
					ofs, len, DO_XXLOCK_ONEBLOCK_LOCK);
	
#ifdef DEBUG_LOCK_BITS
	printk(KERN_DEBUG __FUNCTION__
	       "%s: lock status after, ret=%d\n", __FUNCTION__, ret);
	cfi_intelext_varsize_frob(mtd, do_printlockstatus_oneblock,
				  ofs, len, 0);
#endif

	return ret;
}

static int cfi_intelext_unlock(struct mtd_info *mtd, loff_t ofs, size_t len)
{
	int ret;

#ifdef DEBUG_LOCK_BITS
	printk(KERN_DEBUG "%s: lock status before, ofs=0x%08llx, len=0x%08X\n",
	       __FUNCTION__, ofs, len);
	cfi_intelext_varsize_frob(mtd, do_printlockstatus_oneblock,
				  ofs, len, 0);
#endif

	ret = cfi_intelext_varsize_frob(mtd, do_xxlock_oneblock,
					ofs, len, DO_XXLOCK_ONEBLOCK_UNLOCK);
	
#ifdef DEBUG_LOCK_BITS
	printk(KERN_DEBUG "%s: lock status after, ret=%d\n", __FUNCTION__, ret);
	cfi_intelext_varsize_frob(mtd, do_printlockstatus_oneblock, 
				  ofs, len, 0);
#endif
	
	return ret;
}

static int cfi_intelext_suspend(struct mtd_info *mtd)
{
	struct map_info *map = mtd->priv;
	struct cfi_private *cfi = map->fldrv_priv;
	int i;
	struct flchip *chip;
	int ret = 0;

	for (i=0; !ret && i<cfi->numchips; i++) {
		chip = &cfi->chips[i];

		spin_lock(chip->mutex);

		switch(chip->state) {
		case FL_READY:
		case FL_STATUS:
		case FL_CFI_QUERY:
		case FL_JEDEC_QUERY:
			chip->oldstate = chip->state;
			chip->state = FL_PM_SUSPENDED;
			/* No need to wake_up() on this state change - 
			 * as the whole point is that nobody can do anything
			 * with the chip now anyway.
			 */
		case FL_PM_SUSPENDED:
			break;

		default:
			ret = -EAGAIN;
			break;
		}
		spin_unlock(chip->mutex);
	}

	/* Unlock the chips again */

	if (ret) {
		for (i--; i >=0; i--) {
			chip = &cfi->chips[i];
			
			spin_lock(chip->mutex);
			
			if (chip->state == FL_PM_SUSPENDED) {
				/* No need to force it into a known state here,
				   because we're returning failure, and it didn't
				   get power cycled */
				chip->state = chip->oldstate;
				wake_up(&chip->wq);
			}
			spin_unlock(chip->mutex);
		}
	} 
	
	return ret;
}

static void cfi_intelext_resume(struct mtd_info *mtd)
{
	struct map_info *map = mtd->priv;
	struct cfi_private *cfi = map->fldrv_priv;
	int i;
	struct flchip *chip;

	for (i=0; i<cfi->numchips; i++) {
	
		chip = &cfi->chips[i];

		spin_lock(chip->mutex);
		
		/* Go to known state. Chip may have been power cycled */
		if (chip->state == FL_PM_SUSPENDED) {
			cfi_write(map, CMD(0xFF), 0);
			chip->state = FL_READY;
			wake_up(&chip->wq);
		}

		spin_unlock(chip->mutex);
	}
}

static void cfi_intelext_destroy(struct mtd_info *mtd)
{
	struct map_info *map = mtd->priv;
	struct cfi_private *cfi = map->fldrv_priv;
	kfree(cfi->cmdset_priv);
	kfree(cfi->cfiq);
	kfree(cfi);
	kfree(mtd->eraseregions);
}

static char im_name_1[]="cfi_cmdset_0001";
static char im_name_3[]="cfi_cmdset_0003";

int __init cfi_intelext_init(void)
{
	inter_module_register(im_name_1, THIS_MODULE, &cfi_cmdset_0001);
	inter_module_register(im_name_3, THIS_MODULE, &cfi_cmdset_0001);
	return 0;
}

static void __exit cfi_intelext_exit(void)
{
	inter_module_unregister(im_name_1);
	inter_module_unregister(im_name_3);
}

module_init(cfi_intelext_init);
module_exit(cfi_intelext_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org> et al.");
MODULE_DESCRIPTION("MTD chip driver for Intel/Sharp flash chips");
