flash.c

U-Boot1.1.2是最为常用的嵌入式系统Bootloader

			info->start[2] = base + 0x00006000;
			info->start[3] = base + 0x00008000;
			for (i = 4; i < info->sector_count; i++) {
				info->start[i] = base + (i * 0x00010000) - 0x00030000;
			}
		} else {
			/* set sector offsets for top boot block type		*/
			i = info->sector_count - 1;
			info->start[i--] = base + info->size - 0x00004000;
			info->start[i--] = base + info->size - 0x00006000;
			info->start[i--] = base + info->size - 0x00008000;
			for (; i >= 0; i--) {
				info->start[i] = base + i * 0x00010000;
			}
		}
	}

	/* check for protected sectors */
	for (i = 0; i < info->sector_count; i++) {
		/* read sector protection at sector address, (A7 .. A0) = 0x02 */
		/* D0 = 1 if protected */
#ifdef CONFIG_ADCIOP
		addr2 = (volatile FLASH_WORD_SIZE *)(info->start[i]);
		info->protect[i] = addr2[4] & 1;
#else
		addr2 = (volatile FLASH_WORD_SIZE *)(info->start[i]);
		if ((info->flash_id & FLASH_VENDMASK) == FLASH_MAN_SST)
			info->protect[i] = 0;
		else
			info->protect[i] = addr2[2] & 1;
#endif
	}

	/*
	 * Prevent writes to uninitialized FLASH.
	 */
	if (info->flash_id != FLASH_UNKNOWN) {
#if 0 /* test-only */
#ifdef CONFIG_ADCIOP
		addr2 = (volatile unsigned char *)info->start[0];
		addr2[ADDR0] = 0xAA;
		addr2[ADDR1] = 0x55;
		addr2[ADDR0] = 0xF0;  /* reset bank */
#else
		addr2 = (FLASH_WORD_SIZE *)info->start[0];
		*addr2 = (FLASH_WORD_SIZE)0x00F000F0;	/* reset bank */
#endif
#else /* test-only */
		addr2 = (FLASH_WORD_SIZE *)info->start[0];
		*addr2 = (FLASH_WORD_SIZE)0x00F000F0;	/* reset bank */
#endif /* test-only */
	}

	return (info->size);
}

int wait_for_DQ7(flash_info_t *info, int sect)
{
	ulong start, now, last;
	volatile FLASH_WORD_SIZE *addr = (FLASH_WORD_SIZE *)(info->start[sect]);

	start = get_timer (0);
	last  = start;
	while ((addr[0] & (FLASH_WORD_SIZE)0x00800080) != (FLASH_WORD_SIZE)0x00800080) {
		if ((now = get_timer(start)) > CFG_FLASH_ERASE_TOUT) {
			printf ("Timeout\n");
			return -1;
		}
		/* show that we're waiting */
		if ((now - last) > 1000) {  /* every second */
			putc ('.');
			last = now;
		}
	}
	return 0;
}

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

int	flash_erase (flash_info_t *info, int s_first, int s_last)
{
	volatile FLASH_WORD_SIZE *addr = (FLASH_WORD_SIZE *)(info->start[0]);
	volatile FLASH_WORD_SIZE *addr2;
	int flag, prot, sect, l_sect;
	int i;

	if ((s_first < 0) || (s_first > s_last)) {
		if (info->flash_id == FLASH_UNKNOWN) {
			printf ("- missing\n");
		} else {
			printf ("- no sectors to erase\n");
		}
		return 1;
	}

	if (info->flash_id == FLASH_UNKNOWN) {
		printf ("Can't erase unknown flash type - aborted\n");
		return 1;
	}

	prot = 0;
	for (sect=s_first; sect<=s_last; ++sect) {
		if (info->protect[sect]) {
			prot++;
		}
	}

	if (prot) {
		printf ("- Warning: %d protected sectors will not be erased!\n",
			prot);
	} else {
		printf ("\n");
	}

	l_sect = -1;

	/* Disable interrupts which might cause a timeout here */
	flag = disable_interrupts();

	/* Start erase on unprotected sectors */
	for (sect = s_first; sect<=s_last; sect++) {
		if (info->protect[sect] == 0) { /* not protected */
			addr2 = (FLASH_WORD_SIZE *)(info->start[sect]);
			printf("Erasing sector %p\n", addr2);

			if ((info->flash_id & FLASH_VENDMASK) == FLASH_MAN_SST) {
				addr[ADDR0] = (FLASH_WORD_SIZE)0x00AA00AA;
				addr[ADDR1] = (FLASH_WORD_SIZE)0x00550055;
				addr[ADDR0] = (FLASH_WORD_SIZE)0x00800080;
				addr[ADDR0] = (FLASH_WORD_SIZE)0x00AA00AA;
				addr[ADDR1] = (FLASH_WORD_SIZE)0x00550055;
				addr2[0] = (FLASH_WORD_SIZE)0x00500050;	 /* block erase */
				for (i=0; i<50; i++)
					udelay(1000);  /* wait 1 ms */
			} else {
				addr[ADDR0] = (FLASH_WORD_SIZE)0x00AA00AA;
				addr[ADDR1] = (FLASH_WORD_SIZE)0x00550055;
				addr[ADDR0] = (FLASH_WORD_SIZE)0x00800080;
				addr[ADDR0] = (FLASH_WORD_SIZE)0x00AA00AA;
				addr[ADDR1] = (FLASH_WORD_SIZE)0x00550055;
				addr2[0] = (FLASH_WORD_SIZE)0x00300030;	 /* sector erase */
			}
			l_sect = sect;
			/*
			 * Wait for each sector to complete, it's more
			 * reliable.  According to AMD Spec, you must
			 * issue all erase commands within a specified
			 * timeout.  This has been seen to fail, especially
			 * if printf()s are included (for debug)!!
			 */
			wait_for_DQ7(info, sect);
		}
	}

	/* re-enable interrupts if necessary */
	if (flag)
		enable_interrupts();

	/* wait at least 80us - let's wait 1 ms */
	udelay (1000);

#if 0
	/*
	 * We wait for the last triggered sector
	 */
	if (l_sect < 0)
		goto DONE;
	wait_for_DQ7(info, l_sect);

DONE:
#endif
	/* reset to read mode */
	addr = (FLASH_WORD_SIZE *)info->start[0];
	addr[0] = (FLASH_WORD_SIZE)0x00F000F0;	/* reset bank */

	printf (" done\n");
	return 0;
}

/*-----------------------------------------------------------------------
 * Copy memory to flash, returns:
 * 0 - OK
 * 1 - write timeout
 * 2 - Flash not erased
 */

int write_buff (flash_info_t *info, uchar *src, ulong addr, ulong cnt)
{
	ulong cp, wp, data;
	int i, l, rc;

	wp = (addr & ~3);	/* get lower word aligned address */

	/*
	 * handle unaligned start bytes
	 */
	if ((l = addr - wp) != 0) {
		data = 0;
		for (i=0, cp=wp; i<l; ++i, ++cp) {
			data = (data << 8) | (*(uchar *)cp);
		}
		for (; i<4 && cnt>0; ++i) {
			data = (data << 8) | *src++;
			--cnt;
			++cp;
		}
		for (; cnt==0 && i<4; ++i, ++cp) {
			data = (data << 8) | (*(uchar *)cp);
		}

		if ((rc = write_word(info, wp, data)) != 0) {
			return (rc);
		}
		wp += 4;
	}

	/*
	 * handle word aligned part
	 */
	while (cnt >= 4) {
		data = 0;
		for (i=0; i<4; ++i) {
			data = (data << 8) | *src++;
		}
		if ((rc = write_word(info, wp, data)) != 0) {
			return (rc);
		}
		wp  += 4;
		cnt -= 4;
	}

	if (cnt == 0) {
		return (0);
	}

	/*
	 * handle unaligned tail bytes
	 */
	data = 0;
	for (i=0, cp=wp; i<4 && cnt>0; ++i, ++cp) {
		data = (data << 8) | *src++;
		--cnt;
	}
	for (; i<4; ++i, ++cp) {
		data = (data << 8) | (*(uchar *)cp);
	}

	return (write_word(info, wp, data));
}

/*-----------------------------------------------------------------------
 * Write a word to Flash, returns:
 * 0 - OK
 * 1 - write timeout
 * 2 - Flash not erased
 */
static int write_word (flash_info_t * info, ulong dest, ulong data)
{
	volatile FLASH_WORD_SIZE *addr2 = (FLASH_WORD_SIZE *) (info->start[0]);
	volatile FLASH_WORD_SIZE *dest2 = (FLASH_WORD_SIZE *) dest;
	volatile FLASH_WORD_SIZE *data2 = (FLASH_WORD_SIZE *) & data;
	ulong start;
	int i;

	/* Check if Flash is (sufficiently) erased */
	if ((*((volatile FLASH_WORD_SIZE *) dest) &
	     (FLASH_WORD_SIZE) data) != (FLASH_WORD_SIZE) data) {
		return (2);
	}

	for (i = 0; i < 4 / sizeof (FLASH_WORD_SIZE); i++) {
		int flag;

		/* Disable interrupts which might cause a timeout here */
		flag = disable_interrupts ();

		addr2[ADDR0] = (FLASH_WORD_SIZE) 0x00AA00AA;
		addr2[ADDR1] = (FLASH_WORD_SIZE) 0x00550055;
		addr2[ADDR0] = (FLASH_WORD_SIZE) 0x00A000A0;

		dest2[i] = data2[i];

		/* re-enable interrupts if necessary */
		if (flag)
			enable_interrupts ();

		/* data polling for D7 */
		start = get_timer (0);
		while ((dest2[i] & (FLASH_WORD_SIZE) 0x00800080) !=
		       (data2[i] & (FLASH_WORD_SIZE) 0x00800080)) {

			if (get_timer (start) > CFG_FLASH_WRITE_TOUT) {
				return (1);
			}
		}
	}

	return (0);
}

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