fw_env.c

AT91RM9200的完整启动代码：包括loader, boot及U-boot三部分均已编译通过！欢迎下载使用！

{
	int fd, fdr, rc, otherdev, len, resid;
	erase_info_t erase;
	char *data;

	if ((fd = open (DEVNAME (curdev), mode)) < 0) {
		fprintf (stderr,
			"Can't open %s: %s\n",
			DEVNAME (curdev), strerror (errno));
		return (-1);
	}

	len = sizeof (environment.crc);
	if (HaveRedundEnv) {
		len += sizeof (environment.flags);
	}

	if (mode == O_RDWR) {
		if (HaveRedundEnv) {
			/* switch to next partition for writing */
			otherdev = !curdev;
			if ((fdr = open (DEVNAME (otherdev), mode)) < 0) {
				fprintf (stderr,
					"Can't open %s: %s\n",
					DEVNAME (otherdev),
					strerror (errno));
				return (-1);
			}
		} else {
			otherdev = curdev;
			fdr = fd;
		}
		printf ("Unlocking flash...\n");
		erase.length = DEVESIZE (otherdev);
		erase.start = DEVOFFSET (otherdev);
		ioctl (fdr, MEMUNLOCK, &erase);

		if (HaveRedundEnv) {
			erase.length = DEVESIZE (curdev);
			erase.start = DEVOFFSET (curdev);
			ioctl (fd, MEMUNLOCK, &erase);
			environment.flags = active_flag;
		}

		printf ("Done\n");
		resid = DEVESIZE (otherdev) - CFG_ENV_SIZE;
		if (resid) {
			if ((data = malloc (resid)) == NULL) {
				fprintf (stderr,
					"Cannot malloc %d bytes: %s\n",
					resid,
					strerror (errno));
				return (-1);
			}
			if (lseek (fdr, DEVOFFSET (otherdev) + CFG_ENV_SIZE, SEEK_SET)
				== -1) {
				fprintf (stderr, "seek error on %s: %s\n",
					DEVNAME (otherdev),
					strerror (errno));
				return (-1);
			}
			if ((rc = read (fdr, data, resid)) != resid) {
				fprintf (stderr,
					"read error on %s: %s\n",
					DEVNAME (otherdev),
					strerror (errno));
				return (-1);
			}
		}

		printf ("Erasing old environment...\n");

		erase.length = DEVESIZE (otherdev);
		erase.start = DEVOFFSET (otherdev);
		if (ioctl (fdr, MEMERASE, &erase) != 0) {
			fprintf (stderr, "MTD erase error on %s: %s\n",
				DEVNAME (otherdev),
				strerror (errno));
			return (-1);
		}

		printf ("Done\n");

		printf ("Writing environment to %s...\n", DEVNAME (otherdev));
		if (lseek (fdr, DEVOFFSET (otherdev), SEEK_SET) == -1) {
			fprintf (stderr,
				"seek error on %s: %s\n",
				DEVNAME (otherdev), strerror (errno));
			return (-1);
		}
		if (write (fdr, &environment, len) != len) {
			fprintf (stderr,
				"CRC write error on %s: %s\n",
				DEVNAME (otherdev), strerror (errno));
			return (-1);
		}
		if (write (fdr, environment.data, ENV_SIZE) != ENV_SIZE) {
			fprintf (stderr,
				"Write error on %s: %s\n",
				DEVNAME (otherdev), strerror (errno));
			return (-1);
		}
		if (resid) {
			if (write (fdr, data, resid) != resid) {
				fprintf (stderr,
					"write error on %s: %s\n",
					DEVNAME (curdev), strerror (errno));
				return (-1);
			}
			free (data);
		}
		if (HaveRedundEnv) {
			/* change flag on current active env partition */
			if (lseek (fd, DEVOFFSET (curdev) + sizeof (ulong), SEEK_SET)
				== -1) {
				fprintf (stderr, "seek error on %s: %s\n",
					DEVNAME (curdev), strerror (errno));
				return (-1);
			}
			if (write (fd, &obsolete_flag, sizeof (obsolete_flag)) !=
				sizeof (obsolete_flag)) {
				fprintf (stderr,
					"Write error on %s: %s\n",
					DEVNAME (curdev), strerror (errno));
				return (-1);
			}
		}
		printf ("Done\n");
		printf ("Locking ...\n");
		erase.length = DEVESIZE (otherdev);
		erase.start = DEVOFFSET (otherdev);
		ioctl (fdr, MEMLOCK, &erase);
		if (HaveRedundEnv) {
			erase.length = DEVESIZE (curdev);
			erase.start = DEVOFFSET (curdev);
			ioctl (fd, MEMLOCK, &erase);
			if (close (fdr)) {
				fprintf (stderr,
					"I/O error on %s: %s\n",
					DEVNAME (otherdev),
					strerror (errno));
				return (-1);
			}
		}
		printf ("Done\n");
	} else {

		if (lseek (fd, DEVOFFSET (curdev), SEEK_SET) == -1) {
			fprintf (stderr,
				"seek error on %s: %s\n",
				DEVNAME (curdev), strerror (errno));
			return (-1);
		}
		if (read (fd, &environment, len) != len) {
			fprintf (stderr,
				"CRC read error on %s: %s\n",
				DEVNAME (curdev), strerror (errno));
			return (-1);
		}
		if ((rc = read (fd, environment.data, ENV_SIZE)) != ENV_SIZE) {
			fprintf (stderr,
				"Read error on %s: %s\n",
				DEVNAME (curdev), strerror (errno));
			return (-1);
		}
	}

	if (close (fd)) {
		fprintf (stderr,
			"I/O error on %s: %s\n",
			DEVNAME (curdev), strerror (errno));
		return (-1);
	}

	/* everything ok */
	return (0);
}

/*
 * s1 is either a simple 'name', or a 'name=value' pair.
 * s2 is a 'name=value' pair.
 * If the names match, return the value of s2, else NULL.
 */

static uchar *envmatch (uchar * s1, uchar * s2)
{

	while (*s1 == *s2++)
		if (*s1++ == '=')
			return (s2);
	if (*s1 == '\0' && *(s2 - 1) == '=')
		return (s2);
	return (NULL);
}

/*
 * Prevent confusion if running from erased flash memory
 */
static int env_init (void)
{
	int crc1, crc1_ok;
	uchar *addr1;

	int crc2, crc2_ok;
	uchar flag1, flag2, *addr2;

	if (parse_config ())		/* should fill envdevices */
		return 1;

	if ((addr1 = calloc (1, ENV_SIZE)) == NULL) {
		fprintf (stderr,
			"Not enough memory for environment (%ld bytes)\n",
			ENV_SIZE);
		return (errno);
	}

	/* read environment from FLASH to local buffer */
	environment.data = addr1;
	curdev = 0;
	if (flash_io (O_RDONLY)) {
		return (errno);
	}

	crc1_ok = ((crc1 = crc32 (0, environment.data, ENV_SIZE))
			   == environment.crc);
	if (!HaveRedundEnv) {
		if (!crc1_ok) {
			fprintf (stderr,
				"Warning: Bad CRC, using default environment\n");
			environment.data = default_environment;
			free (addr1);
		}
	} else {
		flag1 = environment.flags;

		curdev = 1;
		if ((addr2 = calloc (1, ENV_SIZE)) == NULL) {
			fprintf (stderr,
				"Not enough memory for environment (%ld bytes)\n",
				ENV_SIZE);
			return (errno);
		}
		environment.data = addr2;

		if (flash_io (O_RDONLY)) {
			return (errno);
		}

		crc2_ok = ((crc2 = crc32 (0, environment.data, ENV_SIZE))
				   == environment.crc);
		flag2 = environment.flags;

		if (crc1_ok && !crc2_ok) {
			environment.data = addr1;
			environment.flags = flag1;
			environment.crc = crc1;
			curdev = 0;
			free (addr2);
		} else if (!crc1_ok && crc2_ok) {
			environment.data = addr2;
			environment.flags = flag2;
			environment.crc = crc2;
			curdev = 1;
			free (addr1);
		} else if (!crc1_ok && !crc2_ok) {
			fprintf (stderr,
				"Warning: Bad CRC, using default environment\n");
			environment.data = default_environment;
			curdev = 0;
			free (addr2);
			free (addr1);
		} else if (flag1 == active_flag && flag2 == obsolete_flag) {
			environment.data = addr1;
			environment.flags = flag1;
			environment.crc = crc1;
			curdev = 0;
			free (addr2);
		} else if (flag1 == obsolete_flag && flag2 == active_flag) {
			environment.data = addr2;
			environment.flags = flag2;
			environment.crc = crc2;
			curdev = 1;
			free (addr1);
		} else if (flag1 == flag2) {
			environment.data = addr1;
			environment.flags = flag1;
			environment.crc = crc1;
			curdev = 0;
			free (addr2);
		} else if (flag1 == 0xFF) {
			environment.data = addr1;
			environment.flags = flag1;
			environment.crc = crc1;
			curdev = 0;
			free (addr2);
		} else if (flag2 == 0xFF) {
			environment.data = addr2;
			environment.flags = flag2;
			environment.crc = crc2;
			curdev = 1;
			free (addr1);
		}
	}
	return (0);
}


static int parse_config ()
{
	struct stat st;

#if defined(CONFIG_FILE)
	/* Fills in DEVNAME(), ENVSIZE(), DEVESIZE(). Or don't. */
	if (get_config (CONFIG_FILE)) {
		fprintf (stderr,
			"Cannot parse config file: %s\n", strerror (errno));
		return 1;
	}
#else
	strcpy (DEVNAME (0), DEVICE1_NAME);
	DEVOFFSET (0) = DEVICE1_OFFSET;
	ENVSIZE (0) = ENV1_SIZE;
	DEVESIZE (0) = DEVICE1_ESIZE;
#ifdef HAVE_REDUND
	strcpy (DEVNAME (1), DEVICE2_NAME);
	DEVOFFSET (1) = DEVICE2_OFFSET;
	ENVSIZE (1) = ENV2_SIZE;
	DEVESIZE (1) = DEVICE2_ESIZE;
	HaveRedundEnv = 1;
#endif
#endif
	if (stat (DEVNAME (0), &st)) {
		fprintf (stderr,
			"Cannot access MTD device %s: %s\n",
			DEVNAME (0), strerror (errno));
		return 1;
	}

	if (HaveRedundEnv && stat (DEVNAME (1), &st)) {
		fprintf (stderr,
			"Cannot access MTD device %s: %s\n",
			DEVNAME (2), strerror (errno));
		return 1;
	}
	return 0;
}

#if defined(CONFIG_FILE)
static int get_config (char *fname)
{
	FILE *fp;
	int i = 0;
	int rc;
	char dump[128];

	if ((fp = fopen (fname, "r")) == NULL) {
		return 1;
	}

	while ((i < 2) && ((rc = fscanf (fp, "%s %lx %lx %lx",
				  DEVNAME (i),
				  &DEVOFFSET (i),
				  &ENVSIZE (i),
				  &DEVESIZE (i)  )) != EOF)) {

		/* Skip incomplete conversions and comment strings */
		if ((rc < 3) || (*DEVNAME (i) == '#')) {
			fgets (dump, sizeof (dump), fp);	/* Consume till end */
			continue;
		}

		i++;
	}
	fclose (fp);

	HaveRedundEnv = i - 1;
	if (!i) {			/* No valid entries found */
		errno = EINVAL;
		return 1;
	} else
		return 0;
}
#endif