2009-05-12 02:37:20 eoors while enabling JFFS2 and MTD
hari a (INDIA)
Message: 73978
Hi All,
I am using Linux version 2.6.22.19-ADI-2008R1.5-svn.
My board has
BF533
8MB flash memory from ST, which is CFI compliant.
Flash is connected to AMS bank-0 ( 0x20000000). I am using latches for higher order addressing.
To make use of JFFS2 and MTD, I followed the link
docs.blackfin.uclinux.org/doku.php?id=linux-kernel:jffs
docs.blackfin.uclinux.org/doku.php?id=linux-kernel:mtd
My configuration details are as follows
Device drivres
<*> Memory Technology Device (MTD) support --->
--Memory Technology Device (MTD) support
[*] MTD partitioning support
[*] Command line partition table parsing
[*] Direct char device access to MTD devices
[*] Caching block device access to MTD devices
RAM/ROM/Flash chip drivers --->
<*> Detect flash chips by Common Flash Interface (CFI) probe
<*> Support for ST (Advanced Architecture) flash chips
<*> Support for RAM chips in bus mapping
<*> Support for ROM chips in bus mapping
Mapping drivers for chip access --->
[*]Support non-linear mappings of flash chips
<*> CFI Flash device in physical memory map
(0x20000000) Physical start address of flash mapping
(0x800000) Physical length of flash mapping
(2)Bank width in octets (NEW)
File systems --->
Miscellaneous filesystems --->
<*> Journalling Flash File System v2 (JFFS2) support
(sub-options are up to you)
(0) JFFS2 debugging verbosity (0 = quiet, 2 = noisy)
Flash Tools --->
--- MTD utils
[*] mtd-utils
[*] flash_erase
[*] flash_eraseall
[*] mkfs.jff2
MTD details after configuration is
grep MTD ./linux-2.6.x/.config | grep =y
CONFIG_MTD=y
CONFIG_MTD_PARTITIONS=y
CONFIG_MTD_CMDLINE_PARTS=y
CONFIG_MTD_CHAR=y
CONFIG_MTD_BLKDEVS=y
CONFIG_MTD_BLOCK=y
CONFIG_MTD_CFI=y
CONFIG_MTD_GEN_PROBE=y
CONFIG_MTD_MAP_BANK_WIDTH_1=y
CONFIG_MTD_MAP_BANK_WIDTH_2=y
CONFIG_MTD_MAP_BANK_WIDTH_4=y
CONFIG_MTD_CFI_I1=y
CONFIG_MTD_CFI_I2=y
CONFIG_MTD_CFI_STAA=y
CONFIG_MTD_CFI_UTIL=y
CONFIG_MTD_RAM=y
CONFIG_MTD_ROM=y
CONFIG_MTD_COMPLEX_MAPPINGS=y
CONFIG_MTD_PHYSMAP=y
Below are kernel prints related to JFFS2 and MTD after kernel booting.
……
…….
JFFS2 version 2.2. 
2001-2006 Red Hat, Inc.
io scheduler noop registered
io scheduler anticipatory registered (default)
io scheduler cfq registered
…..
…..
physmap platform flash device: 00800000 at 20000000
physmap-flash physmap-flash.0: Could not reserve memory region
physmap-flash: probe of physmap-flash.0 failed with error -12
I want to use JFFS2 file system for the flash memory.
I am getting the above mentioned error.
Please guide me how to solve the above error and make MTD, JFFS2 drivers up.
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2009-05-12 08:23:47 Re: eoors while enabling JFFS2 and MTD
Mike Frysinger (UNITED STATES)
Message: 73990
the BF533 doesnt actually have 8 megs of async bank, so lying to the kernel wont help. you need to write a custom flash mapping driver to handle things. i dont know what you mean by "latches" in order to access the high 4 megs, but maybe the existing gpio-flash-addr map can be a useful example.
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2009-05-12 09:48:51 Re: eoors while enabling JFFS2 and MTD
hari a (INDIA)
Message: 73994
Mike:
I mean latch bits are GPIO used for higher order address lines selection.
Could you please tell me where can I find "gpio-flash-addr map " example?
Please guide me how to write custom driver.
Thanks
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2009-05-12 13:42:21 Re: eoors while enabling JFFS2 and MTD
Mike Frysinger (UNITED STATES)
Message: 73996
using GPIO's to address parallel flash isnt supported in 2008R1.5 or earlier. you can look at the driver in trunk at drivers/mtd/maps/gpio-addr-flash.c. look at how some of the tiny boards use it for an example (tcm-bf537).