tools/env: fix environment alignment tests for block devices

commit 183923d3e412500bdc597d1745e2fb6f7f679ec7 enforces that the
environment must start at an erase block boundary.

For block devices the sample fw_env.config does not mandate a erase block size
for block devices. A missing setting defaults to the full env size.

Depending on the environment location the alignment check now errors out for
perfectly legal settings.

Fix this by defaulting to the standard blocksize of 0x200 for environments
stored in a block device.
That keeps the fw_env.config files for block devices working even with that
new check.

Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>

tools/env/fw_env.c

@@ -1291,18 +1291,6 @@ static int check_device_config(int dev)
 	struct stat st;
 	int fd, rc = 0;
 
-	if (DEVOFFSET(dev) % DEVESIZE(dev) != 0) {
-		fprintf(stderr, "Environment does not start on (erase) block boundary\n");
-		errno = EINVAL;
-		return -1;
-	}
-
-	if (ENVSIZE(dev) > ENVSECTORS(dev) * DEVESIZE(dev)) {
-		fprintf(stderr, "Environment does not fit into available sectors\n");
-		errno = EINVAL;
-		return -1;
-	}
-
 	fd = open(DEVNAME(dev), O_RDONLY);
 	if (fd < 0) {
 		fprintf(stderr,
@@ -1335,9 +1323,15 @@ static int check_device_config(int dev)
 			goto err;
 		}
 		DEVTYPE(dev) = mtdinfo.type;
+		if (DEVESIZE(dev) == 0)
+			/* Assume the erase size is the same as the env-size */
+			DEVESIZE(dev) = ENVSIZE(dev);
 	} else {
 		uint64_t size;
 		DEVTYPE(dev) = MTD_ABSENT;
+		if (DEVESIZE(dev) == 0)
+			/* Assume the erase size to be 512 bytes */
+			DEVESIZE(dev) = 0x200;
 
 		/*
 		 * Check for negative offsets, treat it as backwards offset
@@ -1359,6 +1353,22 @@ static int check_device_config(int dev)
 		}
 	}
 
+	if (ENVSECTORS(dev) == 0)
+		/* Assume enough sectors to cover the environment */
+		ENVSECTORS(dev) = DIV_ROUND_UP(ENVSIZE(dev), DEVESIZE(dev));
+
+	if (DEVOFFSET(dev) % DEVESIZE(dev) != 0) {
+		fprintf(stderr, "Environment does not start on (erase) block boundary\n");
+		errno = EINVAL;
+		return -1;
+	}
+
+	if (ENVSIZE(dev) > ENVSECTORS(dev) * DEVESIZE(dev)) {
+		fprintf(stderr, "Environment does not fit into available sectors\n");
+		errno = EINVAL;
+		return -1;
+	}
+
 err:
 	close(fd);
 	return rc;
@@ -1382,10 +1392,10 @@ static int parse_config(struct env_opts *opts)
 	DEVNAME (0) = DEVICE1_NAME;
 	DEVOFFSET (0) = DEVICE1_OFFSET;
 	ENVSIZE (0) = ENV1_SIZE;
-	/* Default values are: erase-size=env-size */
-	DEVESIZE (0) = ENVSIZE (0);
-	/* #sectors=env-size/erase-size (rounded up) */
-	ENVSECTORS (0) = (ENVSIZE(0) + DEVESIZE(0) - 1) / DEVESIZE(0);
+
+	/* Set defaults for DEVESIZE, ENVSECTORS later once we
+	 * know DEVTYPE
+	 */
 #ifdef DEVICE1_ESIZE
 	DEVESIZE (0) = DEVICE1_ESIZE;
 #endif
@@ -1397,10 +1407,10 @@ static int parse_config(struct env_opts *opts)
 	DEVNAME (1) = DEVICE2_NAME;
 	DEVOFFSET (1) = DEVICE2_OFFSET;
 	ENVSIZE (1) = ENV2_SIZE;
-	/* Default values are: erase-size=env-size */
-	DEVESIZE (1) = ENVSIZE (1);
-	/* #sectors=env-size/erase-size (rounded up) */
-	ENVSECTORS (1) = (ENVSIZE(1) + DEVESIZE(1) - 1) / DEVESIZE(1);
+
+	/* Set defaults for DEVESIZE, ENVSECTORS later once we
+	 * know DEVTYPE
+	 */
 #ifdef DEVICE2_ESIZE
 	DEVESIZE (1) = DEVICE2_ESIZE;
 #endif
@@ -1466,13 +1476,9 @@ static int get_config (char *fname)
 
 		DEVNAME(i) = devname;
 
-		if (rc < 4)
-			/* Assume the erase size is the same as the env-size */
-			DEVESIZE(i) = ENVSIZE(i);
-
-		if (rc < 5)
-			/* Assume enough env sectors to cover the environment */
-			ENVSECTORS (i) = (ENVSIZE(i) + DEVESIZE(i) - 1) / DEVESIZE(i);
+		/* Set defaults for DEVESIZE, ENVSECTORS later once we
+		 * know DEVTYPE
+		 */
 
 		i++;
 	}