cfi_probe.c

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/* 
   Common Flash Interface probe code.
   (C) 2000 Red Hat. GPL'd.
   $Id: cfi_probe.c,v 1.12 2000/07/03 13:29:16 dwmw2 Exp $
*/


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

#include <linux/mtd/map.h>
#include <linux/mtd/cfi.h>


struct mtd_info *cfi_probe(struct map_info *);

static void print_cfi_ident(struct cfi_ident *);
static void check_cmd_set(struct map_info *, int, unsigned long);
static struct cfi_private *cfi_cfi_probe(struct map_info *);

static const char im_name[] = "cfi_probe";

/* 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 mtd 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 <[e-mail]> 29 Oct 2000.
 */
struct mtd_info *cfi_probe(struct map_info *map)
{
	struct mtd_info *mtd = NULL;
	struct cfi_private *cfi;
	/* First probe the map to see if we have CFI stuff there. */
	cfi = cfi_cfi_probe(map);
	
	if (!cfi)
		return NULL;

	map->fldrv_priv = cfi;
	map->im_name = im_name;

	/* OK we liked it. Now find a driver for the command set it talks */

	check_cmd_set(map, 1, cfi->chips[0].start); /* First the primary cmdset */
	check_cmd_set(map, 0, cfi->chips[0].start); /* Then the secondary */
	
	/* check_cmd_set() will have used inter_module_get to increase
	   the use count of the module which provides the command set 
	   driver. If we're quitting, we have to decrease it again.
	*/

	if(cfi->cmdset_setup) {
		mtd = cfi->cmdset_setup(map);
		
		if (mtd)
			return mtd;
		inter_module_put(cfi->im_name);
	}
	printk("No supported Vendor Command Set found\n");
	
	kfree(cfi);
	map->fldrv_priv = NULL;
	return NULL;

}

static int cfi_probe_new_chip(struct map_info *map, unsigned long base,
			      struct flchip *chips, struct cfi_private *cfi)
{
	switch (map->buswidth) {
		
	case 1: {
		unsigned char tmp = map->read8(map, base + 0x55);

		/* If there's a device there, put it in Query Mode */
		map->write8(map, 0x98, base+0x55);
		
		if (map->read8(map,base+0x10) == 'Q' &&
		    map->read8(map,base+0x11) == 'R' &&
		    map->read8(map,base+0x12) == 'Y') {
			printk("%s: Found a CFI device at 0x%lx in 8 bit mode\n", map->name, base);
			if (chips) {
				/* Check previous chips for aliases */
				printk("FIXME: Do alias check at line %d of cfi_probe.c\n", __LINE__);
				/* Put it back into Read Mode */
				map->write8(map, 0x98, base+0x55);
			}
			return 1;
		} else {
			if (map->read8(map, base + 0x55) == 0x98) {
				/* It looks like RAM. Put back the stuff we overwrote */
				map->write8(map, tmp, base+0x55);
			}
			return 0;
		}
	}
	
	case 2: {
		__u16 tmp = map->read16(map, base + 0xaa);
		
		/* If there's a device there, put it into Query Mode */
		map->write16(map, 0x9898, base+0xAA);
		
		if (map->read16(map, base+0x20) == cpu_to_le16(0x0051) &&
		    map->read16(map, base+0x22) == cpu_to_le16(0x0052) &&
		    map->read16(map, base+0x24) == cpu_to_le16(0x0059)) {
			printk("%s: Found a CFI device at 0x%lx in 16 bit mode\n", map->name, base);
			if (chips) {
				/* Check previous chips for aliases */
				int i;

				for (i=0; i < cfi->numchips; i++) {
					/* This chip should be in read mode if it's one 
					   we've already touched. */
					if (map->read16(map, chips[i].start+0x20) == cpu_to_le16(0x0051) &&
					    map->read16(map, chips[i].start+0x22) == cpu_to_le16(0x0052) &&
					    map->read16(map, chips[i].start+0x24) == cpu_to_le16(0x0059)){
						/* Either the old chip has got 'Q''R''Y' in a most
						   unfortunate place, or it's an alias of the new
						   chip. Double-check that it's in read mode, and check. */
						map->write16(map, 0xffff, chips[i].start+0x20);
						if (map->read16(map, chips[i].start+0x20) == cpu_to_le16(0x0051) &&
						    map->read16(map, chips[i].start+0x22) == cpu_to_le16(0x0052) &&
						    map->read16(map, chips[i].start+0x24) == cpu_to_le16(0x0059)) {
							/* Yes it's got QRY for data. Most unfortunate. 
							   Stick the old one in read mode too. */
							map->write16(map, 0xffff, base);
							if (map->read16(map, base+0x20) == cpu_to_le16(0x0051) &&
							    map->read16(map, base+0x22) == cpu_to_le16(0x0052) &&
							    map->read16(map, base+0x24) == cpu_to_le16(0x0059)) {
								/* OK, so has the new one. Assume it's an alias */
								printk("T'was probably an alias for the chip at 0x%lx\n", chips[i].start);
								return 1;
							} /* else no, they're different, fall through. */
						} else {
							/* No the old one hasn't got QRY for data. Therefore,
							   it's an alias of the new one. */
							map->write16(map, 0xffff, base+0xaa);
							/* Just to be paranoid. */
							map->write16(map, 0xffff, chips[i].start+0xaa);
							printk("T'was an alias for the chip at 0x%lx\n", chips[i].start);
							return 1;
						}
					} 
					/* No, the old one didn't look like it's in query mode. Next. */
				}
				
				/* OK, if we got to here, then none of the previous chips appear to
				   be aliases for the current one. */
				if (cfi->numchips == MAX_CFI_CHIPS) {
					printk("%s: Too many flash chips detected. Increase MAX_CFI_CHIPS from %d.\n", map->name, MAX_CFI_CHIPS);
					/* Doesn't matter about resetting it to Read Mode - we're not going to talk to it anyway */
					return 1;
				}
				printk("Not an alias. Adding\n");
				chips[cfi->numchips].start = base;
				chips[cfi->numchips].state = FL_READY;
				chips[cfi->numchips].mutex = &chips[cfi->numchips]._spinlock;
				cfi->numchips++;

				/* Put it back into Read Mode */
				map->write16(map, 0xffff, base+0xaa);
			}
			
			return 1;
		}	
		else if (map->read16(map, base+0x20) == 0x5151 &&
			 map->read16(map, base+0x22) == 0x5252 &&
			 map->read16(map, base+0x24) == 0x5959) {
			printk("%s: Found a coupled pair of CFI devices at %lx in 8 bit mode\n",
			       map->name, base);
			if (chips) {
				/* Check previous chips for aliases */
				printk("FIXME: Do alias check at line %d of cfi_probe.c\n", __LINE__);

				/* Put it back into Read Mode */
				map->write16(map, 0xffff, base+0xaa);
			}

			return 2;
		} else {
			if (map->read16(map, base+0xaa) == 0x9898) {
				/* It looks like RAM. Put back the stuff we overwrote */
				map->write16(map, tmp, base+0xaa);
			}
			return 0;
		}
	}

		
	case 4: {
		__u32 tmp = map->read32(map, base+0x154);
		
		/* If there's a device there, put it into Query Mode */
		map->write32(map, 0x98989898, base+0x154);
		
		if (map->read32(map, base+0x40) == cpu_to_le32(0x00000051) &&
		    map->read32(map, base+0x44) == cpu_to_le32(0x00000052) &&
		    map->read32(map, base+0x48) == cpu_to_le32(0x00000059)) {
				/* This isn't actually in the CFI spec - only x8 and x16 are. */
			printk("%s: Found a CFI device at %lx in 32 bit mode\n", map->name, base);
			if (chips) {
				/* Check previous chips for aliases */
				printk("FIXME: Do alias check at line %d of cfi_probe.c\n", __LINE__);

				/* Put it back into read mode */
				map->write32(map, 0xffffffff, base+0x154);
			}
			return 1;
		} 
		else if (map->read32(map, base+0x40) == cpu_to_le32(0x00510051) &&
			 map->read32(map, base+0x44) == cpu_to_le32(0x00520052) &&
			 map->read32(map, base+0x48) == cpu_to_le32(0x00590059)) {
			printk("%s: Found a coupled pair of CFI devices at location %lx in 16 bit mode\n", map->name, base);
			if (chips) {
				/* Check previous chips for aliases */
				printk("FIXME: Do alias check at line %d of cfi_probe.c\n", __LINE__);

				/* Put it back into read mode */
				map->write32(map, 0xffffffff, base+0x154);
			}
			return 2;
		}
		else if (map->read32(map, base+0x40) == 0x51515151 &&
			 map->read32(map, base+0x44) == 0x52525252 &&
			 map->read32(map, base+0x48) == 0x59595959) {
			printk("%s: Found four side-by-side CFI devices at location %lx in 8 bit mode\n", map->name, base);
			if (chips) {
				/* Check previous chips for aliases */
				printk("FIXME: Do alias check at line %d of cfi_probe.c\n", __LINE__);

				/* Put it back into read mode */
				map->write32(map, 0xffffffff, base+0x154);
			}
			return 4;
		} else {
			if (map->read32(map, base+0x154) == 0x98989898) {
				/* It looks like RAM. Put back the stuff we overwrote */
				map->write32(map, tmp, base+0x154);
			}
			return 0;
		}
	}	
	default:
		printk(KERN_WARNING "cfi_probe called with strange buswidth %d\n", map->buswidth);
		return 0;
	}
}

static struct cfi_private *cfi_cfi_probe(struct map_info *map)
{
	unsigned long base=0;
	struct cfi_private cfi;