u-boot/doc/README.JFFS2

JFFS2 options and usage.
-----------------------

JFFS2 in U-Boot is a read only implementation of the file system in
Linux with the same name. To use JFFS2 define CONFIG_CMD_JFFS2.

The module adds three new commands.
fsload  - load binary file from a file system image
fsinfo  - print information about file systems
ls      - list files in a directory
chpart  - change active partition

If you do now need the commands, you can enable the filesystem separately
with CONFIG_FS_JFFS2 and call the jffs2 functions yourself.

If you boot from a partition which is mounted writable, and you
update your boot environment by replacing single files on that
partition, you should also define CONFIG_SYS_JFFS2_SORT_FRAGMENTS. Scanning
the JFFS2 filesystem takes *much* longer with this feature, though.
Sorting is done while inserting into the fragment list, which is
more or less a bubble sort. That algorithm is known to be O(n^2),
thus you should really consider if you can avoid it!


There only one way for JFFS2 to find the disk. It uses the flash_info
structure to find the start of a JFFS2 disk (called partition in the code)
and you can change where the partition is with two defines.

CONFIG_SYS_JFFS2_FIRST_BANK
	defined the first flash bank to use

CONFIG_SYS_JFFS2_FIRST_SECTOR
	defines the first sector to use
---

TODO.

	Remove the assumption that JFFS can dereference a pointer
	into the disk. The current code do not work with memory holes
	or hardware with a sliding window (PCMCIA).
Initial revision 2002-11-03 08:24:07 +08:00			`JFFS2 options and usage.`
			`-----------------------`

			`JFFS2 in U-Boot is a read only implementation of the file system in`
disk/ doc/ lib_/ and tools/: Remove lingering references to CFG_CMD_ symbols. Fixed some broken instances of "#ifdef CMD_CFG_IDE" too. Those always evaluated TRUE, and thus were always compiled even when IDE really wasn't defined/wanted. Signed-off-by: Jon Loeliger <jdl@freescale.com> 2007-07-11 00:19:50 +08:00			`Linux with the same name. To use JFFS2 define CONFIG_CMD_JFFS2.`
Initial revision 2002-11-03 08:24:07 +08:00
			`The module adds three new commands.`
			`fsload - load binary file from a file system image`
			`fsinfo - print information about file systems`
			`ls - list files in a directory`
* Patch by Paul Ruhland, 17 May 2004: - Add support for the Logic Zoom LH7A40x based SDK board(s), specifically the LPD7A400. * Patches by Robert Schwebel, 15 May 2004: - call MAC address reading code also for SMSC91C111; - make SMSC91C111 timeout configurable, remove duplicate code - fix get_timer() for PXA - update doc/README.JFFS2 - use "bootfile" env variable also for jffs2 2004-06-09 21:37:52 +08:00			`chpart - change active partition`
Initial revision 2002-11-03 08:24:07 +08:00
fs: Kconfig: Add a separate option for FS_JFFS2 Rather than using CMD_JFFS2 for both the filesystem and its command, we should have a separate option for each. This allows us to enable JFFS2 support without the command, if desired, which reduces U-Boot's size slightly. Signed-off-by: Simon Glass <sjg@chromium.org> 2017-05-17 17:25:38 +08:00			`If you do now need the commands, you can enable the filesystem separately`
			`with CONFIG_FS_JFFS2 and call the jffs2 functions yourself.`

* Avoid flicker on the TRAB's VFD by synchronizing the enable with the HSYNC/VSYNC. Requires new CPLD code (Version 101 for Rev. 100 boards, version 153 for Rev. 200 boards). * Patch by Vladimir Gurevich, 12 Mar 2003: Fix relocation problem of statically initialized string pointers in common/cmd_pci.c * Patch by Kai-Uwe Bl�m, 12 Mar 2003: Cleanup & bug fixes for JFFS2 code: - the memory mangement was broken. It caused havoc on malloc by writing beyond the block boundaries. - the length calculation for files was wrong, sometimes resulting in short file reads. - data copying now optionally takes fragment version numbers into account, to avoid copying from older data. See doc/README.JFFS2 for details. 2003-03-15 04:47:52 +08:00			`If you boot from a partition which is mounted writable, and you`
			`update your boot environment by replacing single files on that`
rename CFG_ macros to CONFIG_SYS Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> 2008-10-16 21:01:15 +08:00			`partition, you should also define CONFIG_SYS_JFFS2_SORT_FRAGMENTS. Scanning`
* Avoid flicker on the TRAB's VFD by synchronizing the enable with the HSYNC/VSYNC. Requires new CPLD code (Version 101 for Rev. 100 boards, version 153 for Rev. 200 boards). * Patch by Vladimir Gurevich, 12 Mar 2003: Fix relocation problem of statically initialized string pointers in common/cmd_pci.c * Patch by Kai-Uwe Bl�m, 12 Mar 2003: Cleanup & bug fixes for JFFS2 code: - the memory mangement was broken. It caused havoc on malloc by writing beyond the block boundaries. - the length calculation for files was wrong, sometimes resulting in short file reads. - data copying now optionally takes fragment version numbers into account, to avoid copying from older data. See doc/README.JFFS2 for details. 2003-03-15 04:47:52 +08:00			`the JFFS2 filesystem takes much longer with this feature, though.`
			`Sorting is done while inserting into the fragment list, which is`
			`more or less a bubble sort. That algorithm is known to be O(n^2),`
			`thus you should really consider if you can avoid it!`

Initial revision 2002-11-03 08:24:07 +08:00
README: Drop unused JFFS2 options There appear to be neither implemented nor used. Drop them. Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: York Sun <york.sun@nxp.com> 2016-10-03 08:00:59 +08:00			`There only one way for JFFS2 to find the disk. It uses the flash_info`
			`structure to find the start of a JFFS2 disk (called partition in the code)`
			`and you can change where the partition is with two defines.`
Initial revision 2002-11-03 08:24:07 +08:00
rename CFG_ macros to CONFIG_SYS Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> 2008-10-16 21:01:15 +08:00			`CONFIG_SYS_JFFS2_FIRST_BANK`
Initial revision 2002-11-03 08:24:07 +08:00			`defined the first flash bank to use`

rename CFG_ macros to CONFIG_SYS Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> 2008-10-16 21:01:15 +08:00			`CONFIG_SYS_JFFS2_FIRST_SECTOR`
Initial revision 2002-11-03 08:24:07 +08:00			`defines the first sector to use`
			`---`

			`TODO.`

* Code cleanup: - remove trailing white space, trailing empty lines, C++ comments, etc. - split cmd_boot.c (separate cmd_bdinfo.c and cmd_load.c) * Patches by Kenneth Johansson, 25 Jun 2003: - major rework of command structure (work done mostly by Michal Cendrowski and Joakim Kristiansen) 2003-06-28 05:31:46 +08:00			`Remove the assumption that JFFS can dereference a pointer`
			`into the disk. The current code do not work with memory holes`
			`or hardware with a sliding window (PCMCIA).`