env: enable accessing the environment in an EXT4 partition

For example to store the environment in a file named "/uboot.env" in MMC
"0", where partition "1" contains the EXT4 filesystem, the following
configs should be added to the board's default config:

  CONFIG_ENV_IS_IN_EXT4=y
  CONFIG_ENV_EXT4_DEVICE_AND_PART="0:1"
  CONFIG_ENV_EXT4_FILE="/uboot.env"
  CONFIG_ENV_EXT4_INTERFACE="mmc"

Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
[trini: Fix some line over 80 chars issues]
Signed-off-by: Tom Rini <trini@konsulko.com>

env/Kconfig

@@ -81,6 +81,13 @@ config ENV_IS_IN_FAT
 	  - CONFIG_FAT_WRITE:
 	  This must be enabled. Otherwise it cannot save the environment file.
 
+config ENV_IS_IN_EXT4
+	bool "Environment is in a EXT4 filesystem"
+	depends on !CHAIN_OF_TRUST
+	select EXT4_WRITE
+	help
+	  Define this if you want to use the EXT4 file system for the environment.
+
 config ENV_IS_IN_FLASH
 	bool "Environment in flash memory"
 	depends on !CHAIN_OF_TRUST
@@ -396,6 +403,38 @@ config ENV_FAT_FILE
 	  It's a string of the FAT file name. This file use to store the
 	  environment.
 
+config ENV_EXT4_INTERFACE
+	string "Name of the block device for the environment"
+	depends on ENV_IS_IN_EXT4
+	help
+	  Define this to a string that is the name of the block device.
+
+config ENV_EXT4_DEVICE_AND_PART
+	string "Device and partition for where to store the environemt in EXT4"
+	depends on ENV_IS_IN_EXT4
+	help
+	  Define this to a string to specify the partition of the device. It can
+	  be as following:
+
+	    "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
+	       - "D:P": device D partition P. Error occurs if device D has no
+	                partition table.
+	       - "D:0": device D.
+	       - "D" or "D:": device D partition 1 if device D has partition
+	                      table, or the whole device D if has no partition
+	                      table.
+	       - "D:auto": first partition in device D with bootable flag set.
+	                   If none, first valid partition in device D. If no
+	                   partition table then means device D.
+
+config ENV_EXT4_FILE
+	string "Name of the EXT4 file to use for the environemnt"
+	depends on ENV_IS_IN_EXT4
+	default "uboot.env"
+	help
+	  It's a string of the EXT4 file name. This file use to store the
+	  environment (explicit path to the file)
+
 if ARCH_SUNXI
 
 config ENV_OFFSET

env/env.c

@@ -32,6 +32,8 @@ static enum env_location env_get_default_location(void)
 		return ENVL_EEPROM;
 	else if IS_ENABLED(CONFIG_ENV_IS_IN_FAT)
 		return ENVL_FAT;
+	else if IS_ENABLED(CONFIG_ENV_IS_IN_EXT4)
+		return ENVL_EXT4;
 	else if IS_ENABLED(CONFIG_ENV_IS_IN_FLASH)
 		return ENVL_FLASH;
 	else if IS_ENABLED(CONFIG_ENV_IS_IN_MMC)

env/ext4.c

@@ -46,9 +46,9 @@ static int env_ext4_save(void)
 	if (err)
 		return err;
 
-	part = blk_get_device_part_str(EXT4_ENV_INTERFACE,
-					EXT4_ENV_DEVICE_AND_PART,
-					&dev_desc, &info, 1);
+	part = blk_get_device_part_str(CONFIG_ENV_EXT4_INTERFACE,
+				       CONFIG_ENV_EXT4_DEVICE_AND_PART,
+				       &dev_desc, &info, 1);
 	if (part < 0)
 		return 1;
 
@@ -57,16 +57,19 @@ static int env_ext4_save(void)
 
 	if (!ext4fs_mount(info.size)) {
 		printf("\n** Unable to use %s %s for saveenv **\n",
-		       EXT4_ENV_INTERFACE, EXT4_ENV_DEVICE_AND_PART);
+		       CONFIG_ENV_EXT4_INTERFACE,
+		       CONFIG_ENV_EXT4_DEVICE_AND_PART);
 		return 1;
 	}
 
-	err = ext4fs_write(EXT4_ENV_FILE, (void *)&env_new, sizeof(env_t));
+	err = ext4fs_write(CONFIG_ENV_EXT4_FILE, (void *)&env_new,
+			   sizeof(env_t));
 	ext4fs_close();
 
 	if (err == -1) {
 		printf("\n** Unable to write \"%s\" from %s%d:%d **\n",
-			EXT4_ENV_FILE, EXT4_ENV_INTERFACE, dev, part);
+			CONFIG_ENV_EXT4_FILE, CONFIG_ENV_EXT4_INTERFACE, dev,
+			part);
 		return 1;
 	}
 
@@ -84,9 +87,9 @@ static int env_ext4_load(void)
 	int err;
 	loff_t off;
 
-	part = blk_get_device_part_str(EXT4_ENV_INTERFACE,
-					EXT4_ENV_DEVICE_AND_PART,
-					&dev_desc, &info, 1);
+	part = blk_get_device_part_str(CONFIG_ENV_EXT4_INTERFACE,
+				       CONFIG_ENV_EXT4_DEVICE_AND_PART,
+				       &dev_desc, &info, 1);
 	if (part < 0)
 		goto err_env_relocate;
 
@@ -95,16 +98,19 @@ static int env_ext4_load(void)
 
 	if (!ext4fs_mount(info.size)) {
 		printf("\n** Unable to use %s %s for loading the env **\n",
-		       EXT4_ENV_INTERFACE, EXT4_ENV_DEVICE_AND_PART);
+		       CONFIG_ENV_EXT4_INTERFACE,
+		       CONFIG_ENV_EXT4_DEVICE_AND_PART);
 		goto err_env_relocate;
 	}
 
-	err = ext4_read_file(EXT4_ENV_FILE, buf, 0, CONFIG_ENV_SIZE, &off);
+	err = ext4_read_file(CONFIG_ENV_EXT4_FILE, buf, 0, CONFIG_ENV_SIZE,
+			     &off);
 	ext4fs_close();
 
 	if (err == -1) {
 		printf("\n** Unable to read \"%s\" from %s%d:%d **\n",
-			EXT4_ENV_FILE, EXT4_ENV_INTERFACE, dev, part);
+			CONFIG_ENV_EXT4_FILE, CONFIG_ENV_EXT4_INTERFACE, dev,
+			part);
 		goto err_env_relocate;
 	}