Read/write VFAT support from Rockbox-3.3 FAT stack

Add read/write VFAT support from Rockbox-3.3 FAT stack.
It should be also applicable to the unmodified 2009.11 U-Boot release.

Note that is was taken as is from Rockbox and from a older U-Boot
Rockbox patch. "checkpatch" shows very many coding style errors and
warnings, but it is tedious work to clean this up.

To make this patch work an additional mmc_block_write() board support
routine and the errno variable are needed.
Furthermore following defines in the board config header file:
	#define CONFIG_ROCKBOX_FAT	1
	#define CONFIG_U_BOOT		1
	#define CONFIG_SUPPORT_VFAT	1
	#define CONFIG_CMD_TREE_FAT
This will be added in a follow-up patch.

This patch is based on the patch from Etienne Carriere
<etienne.carriere@stericsson.com> for the U671x U-Boot:

This commit adds FAT write support to u-boot native read-only FAT code.
Commit initially applied on u-boot-v2009.01
(SHA1: 72d15e705bc3983884105cb7755c7ba80e74a0a5)

Based on FAT stack dumped from Rockbox package v3.1 (www.rockbox.org).
Based on initial Rockbox FAT stack integration in u-boot by Keith Outwater
(outwater@comcast.net).
Current porting is aligned with Rockbox v3.3 FAT stack.

Enable upon config switches:
CONFIG_CMD_FAT
CONFIG_ROCKBOX_FAT
CONFIG_CMD_TREE_FAT   (recommended)
CONFIG_SUPPORT_VFAT   (recommended)

C code APIs (from U-boot native FAT support):
int  fat_register_device(block_dev_desc_t *dev_desc, int part_no);
long file_fat_read(const char *path, void *buf, unsigned long maxsize);
int file_fat_ls(const char *dirname);
int file_fat_detectfs(void);

C code APIs (added by Rockbox FAT support):
long file_fat_write(const char *path, void *buf, unsigned long maxsize);
int file_fat_rm(const char *path);
int file_fat_rmdir(const char *path);
int file_fat_mkdir(const char *path);
int file_fat_cd(const char *path);
int file_fat_pwd(void);
int file_fat_mv(const char *oldpath, const char *newpath);
unsigned int rockbox_fat_free(unsigned long size_kbyte);
unsigned int rockbox_fat_size(void);

Use "help fat" from u-boot console to see available commands.

ST-Ericsson ID: WP264488

Change-Id: I9afc29ecb80f9152bd8534bbf11e47e54cfad796
Signed-off-by: Michael Brandt <michael.brandt@stericsson.com>
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/3009

1 files changed, 36 insertions, 0 deletions

diff --git a/README b/README
index 22e35c39b..ab3667fb7 100644
--- a/README
+++ b/README
@@ -737,6 +737,42 @@ The following options need to be configured:
 		Note that if the RTC uses I2C, then the I2C interface
 		must also be configured. See I2C Support, below.
 
+ - Rockbox FAT Filesystem Driver:
+		U-Boot includes a port of the FAT filesystem driver from the
+		Rockbox project (www.rockbox.org). To configure U-Boot to
+		use thus driver (and to NOT use the default FAT12/16/32
+		read-only driver), define CONFIG_ROCKBOX_FAT along with
+		CONFIG_CMD_FAT.
+
+		Note that the rockbox FAT driver does not support FAT12, but
+		it does support FAT16 and FAT32 (with long file names) and you
+		get FAT read and write functionality too.
+
+		CFG_ROCKBOX_FAT_MAX_OPEN_FILES (optional) - define this to
+		specify the maximum number of files that may be open at one
+		time. The default is 1. This should be sufficient unless you
+		are planning to use the posix-like interface to a FAT
+		filesystem and need more than one file open at a time.
+
+		CFG_ROCKBOX_FAT_MAX_OPEN_DIRS (optional) - define this to
+		specify the maximum number of simultaneously open directories.
+		The default is 8.
+
+		CFG_ROCKBOX_FAT_MAX_SECS_PER_XFER (optional) - define this
+		parameter in order to allow the filesystem driver to request
+		transfer (read or write) of more than 256 sectors per transfer
+		request. If you override the default, MAKE SURE that your
+		disk driver can handle more than 256 sectors per transfer
+		request.
+
+		The rockbox driver expects to set the 'errno' variable, so
+		your BSP needs to declare it as follows:
+
+			int errno;
+
+		If you want to include strerror() support, define
+		CONFIG_STRERROR.
+
 - GPIO Support:
 		CONFIG_PCA953X		- use NXP's PCA953X series I2C GPIO
 		CONFIG_PCA953X_INFO	- enable pca953x info command