Add support for loading and saving the environment to a FAT partition

The following must be defined:

CONFIG_ENV_IS_IN_FAT
	Enable this saving environment to FAT.

FAT_ENV_INTERFACE
	Interface the FAT resides on (e.g. mmc).

FAT_ENV_DEVICE
	The interface device number (e.g. 0 for mmc0)

FAT_ENV_PART
	The device part (e.g. 1 for mmc0:1)

FAT_ENV_FILE
	The filename of the environment file.

Author:    Maximilian Schwerin <mvs@tigris.de>

Removed dead DEBUG comment.
Signed-off-by: Wolfgang Denk <wd@denx.de>

common/Makefile

@@ -54,6 +54,7 @@ COBJS-$(CONFIG_ENV_IS_IN_NVRAM) += env_embedded.o
 COBJS-$(CONFIG_ENV_IS_IN_FLASH) += env_flash.o
 COBJS-$(CONFIG_ENV_IS_IN_MG_DISK) += env_mgdisk.o
 COBJS-$(CONFIG_ENV_IS_IN_MMC) += env_mmc.o
+COBJS-$(CONFIG_ENV_IS_IN_FAT) += env_fat.o
 COBJS-$(CONFIG_ENV_IS_IN_NAND) += env_nand.o
 COBJS-$(CONFIG_ENV_IS_IN_NVRAM) += env_nvram.o
 COBJS-$(CONFIG_ENV_IS_IN_ONENAND) += env_onenand.o

common/cmd_nvedit.c

@@ -61,13 +61,14 @@ DECLARE_GLOBAL_DATA_PTR;
 	!defined(CONFIG_ENV_IS_IN_DATAFLASH)	&& \
 	!defined(CONFIG_ENV_IS_IN_MG_DISK)	&& \
 	!defined(CONFIG_ENV_IS_IN_MMC)		&& \
+	!defined(CONFIG_ENV_IS_IN_FAT)		&& \
 	!defined(CONFIG_ENV_IS_IN_NAND)		&& \
 	!defined(CONFIG_ENV_IS_IN_NVRAM)	&& \
 	!defined(CONFIG_ENV_IS_IN_ONENAND)	&& \
 	!defined(CONFIG_ENV_IS_IN_SPI_FLASH)	&& \
 	!defined(CONFIG_ENV_IS_NOWHERE)
 # error Define one of CONFIG_ENV_IS_IN_{EEPROM|FLASH|DATAFLASH|ONENAND|\
-SPI_FLASH|MG_DISK|NVRAM|MMC} or CONFIG_ENV_IS_NOWHERE
+SPI_FLASH|MG_DISK|NVRAM|MMC|FAT} or CONFIG_ENV_IS_NOWHERE
 #endif
 
 #define XMK_STR(x)	#x

common/env_fat.c

@@ -0,0 +1,156 @@
+/*
+ * (c) Copyright 2011 by Tigris Elektronik GmbH
+ *
+ * Author:
+ *  Maximilian Schwerin <mvs@tigris.de>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+
+#include <command.h>
+#include <environment.h>
+#include <linux/stddef.h>
+#include <malloc.h>
+#include <search.h>
+#include <errno.h>
+#include <fat.h>
+#include <mmc.h>
+
+char *env_name_spec = "FAT";
+
+env_t *env_ptr;
+
+DECLARE_GLOBAL_DATA_PTR;
+
+uchar env_get_char_spec(int index)
+{
+	return *((uchar *)(gd->env_addr + index));
+}
+
+int env_init(void)
+{
+	/* use default */
+	gd->env_addr = (ulong)&default_environment[0];
+	gd->env_valid = 1;
+
+	return 0;
+}
+
+#ifdef CONFIG_CMD_SAVEENV
+int saveenv(void)
+{
+	env_t	env_new;
+	ssize_t	len;
+	char	*res;
+	block_dev_desc_t *dev_desc = NULL;
+	int dev = FAT_ENV_DEVICE;
+	int part = FAT_ENV_PART;
+
+	res = (char *)&env_new.data;
+	len = hexport_r(&env_htab, '\0', &res, ENV_SIZE, 0, NULL);
+	if (len < 0) {
+		error("Cannot export environment: errno = %d\n", errno);
+		return 1;
+	}
+
+#ifdef CONFIG_MMC
+	if (strcmp (FAT_ENV_INTERFACE, "mmc") == 0) {
+		struct mmc *mmc = find_mmc_device(dev);
+
+		if (!mmc) {
+			printf("no mmc device at slot %x\n", dev);
+			return 1;
+		}
+
+		mmc->has_init = 0;
+		mmc_init(mmc);
+	}
+#endif /* CONFIG_MMC */
+
+	dev_desc = get_dev(FAT_ENV_INTERFACE, dev);
+	if (dev_desc == NULL) {
+		printf("Failed to find %s%d\n",
+			FAT_ENV_INTERFACE, dev);
+		return 1;
+	}
+	if (fat_register_device(dev_desc, part) != 0) {
+		printf("Failed to register %s%d:%d\n",
+			FAT_ENV_INTERFACE, dev, part);
+		return 1;
+	}
+
+	env_new.crc = crc32(0, env_new.data, ENV_SIZE);
+	if (file_fat_write(FAT_ENV_FILE, (void *)&env_new, sizeof(env_t)) == -1) {
+		printf("\n** Unable to write \"%s\" from %s%d:%d **\n",
+			FAT_ENV_FILE, FAT_ENV_INTERFACE, dev, part);
+		return 1;
+	}
+
+	puts("done\n");
+	return 0;
+}
+#endif /* CONFIG_CMD_SAVEENV */
+
+void env_relocate_spec(void)
+{
+	char buf[CONFIG_ENV_SIZE];
+	block_dev_desc_t *dev_desc = NULL;
+	int dev = FAT_ENV_DEVICE;
+	int part = FAT_ENV_PART;
+
+#ifdef CONFIG_MMC
+	if (strcmp (FAT_ENV_INTERFACE, "mmc") == 0) {
+		struct mmc *mmc = find_mmc_device(dev);
+
+		if (!mmc) {
+			printf("no mmc device at slot %x\n", dev);
+			set_default_env(NULL);
+			return;
+		}
+
+		mmc->has_init = 0;
+		mmc_init(mmc);
+	}
+#endif /* CONFIG_MMC */
+
+	dev_desc = get_dev(FAT_ENV_INTERFACE, dev);
+	if (dev_desc == NULL) {
+		printf("Failed to find %s%d\n",
+			FAT_ENV_INTERFACE, dev);
+		set_default_env(NULL);
+		return;
+	}
+	if (fat_register_device(dev_desc, part) != 0) {
+		printf("Failed to register %s%d:%d\n",
+			FAT_ENV_INTERFACE, dev, part);
+		set_default_env(NULL);
+		return;
+	}
+
+	if (file_fat_read(FAT_ENV_FILE, (unsigned char *)&buf, CONFIG_ENV_SIZE) == -1) {
+		printf("\n** Unable to read \"%s\" from %s%d:%d **\n",
+			FAT_ENV_FILE, FAT_ENV_INTERFACE, dev, part);
+		set_default_env(NULL);
+		return;
+	}
+
+	env_import(buf, 1);
+}