Re: [microblaze-uclinux] JFFS2 and MTD

[John Williams <jwilliams@itee.uq.edu.au>]

Hi Robert,

Robert Swindells wrote:

> John Williams wrote:
> 
>>Robert Swindells wrote:
>>
>>>>I haven't - I saw that the output of mkfs.jffs2 when run on an empty 
>>>>directory was itself empty, so just figured I could mount straight on 
>>>>top of an empty mtdblock device.
>>>
>>>Had you erased the area ?
> 
> 
>>Yes -
>>$ eraseall /dev/mtd6
>>$ mount -t jffs2 /dev/mtd6 /var
> 
> 
>>It is silent, no errors reported, but then the behaviour on trying to 
>>create files etc.
> 
> 
> I would erase it before trying to boot if you can.

I've tried that - still the same.

>>should the jffs2 block size be related to some physical parameter of the 
>>system?  What is the importance?
> 
> 
> The JFFS2 block size is the flash block size. It needs to know this in
> order to do wear levelling and to garbage collect dirty blocks.

Ah ok well that is important - I'll check it out.

>>>>Is JFFS2 trying to mount some kind of default fdile system?  This is all 
>>>>happening before the shell starts, and before I can do any explicit 
>>>>mount -t jffs2 commands.
>>>
>>>
>>>It isn't trying to mount anything at this stage, it will just format
>>>up any blocks that are not marked as being already used. This works
>>>best if the unused blocks are cleared.
> 
> 
>>Sure - but how does the jffs2 module initialisation know which of the 
>>flash partitions are available for use?  e.g. the mtd5 (image) segment 
>>is not for jffs2, it is a raw kernel / filesys image.  I don't want 
>>jffs2 playing anywhere near it.
> 
> 
> Can you grab the boot messages just before setting up JFFS2 ?

Yes - it's attached.  The message "magics are XXX, XXX" are some 
debugging messages from my hacks on the ext2 driver.

>>Should I be writing a partition table somewhere?
> 
> No, you only need one if you don't want to hard code partition sizes
> into the kernel.

Do you mean the MTD map, mbvanilla-flash.c??

I've noted that I am also having trouble with the ramfs driver - it 
seems to start up properly but any writes to it fail with "no space on 
device".  I traced into the kernel to see that the inode associated with 
the ramdisk block driver has a size of zero, so all writes fail.  The 
actual write_page() code in the driver never gets called.

I don't know why this is but am suspicious that it's related to the 
failure on the mtdblock devices too.  I can read and write quite happily 
from the mtd char devices, but jffs2 (which should just *work*) is 
unhappy on the mtdblock.

Need to look into it further tomorrow (today's a public holiday here).

Thanks,
John

Linux version 2.4.21-uc0 (jwilliam@g435-9029) (gcc version 2.95.3-4 Xilinx EDK 6.1 Build EDK_G.3) #1083 Tue Aug 12 12:44:13 EST 2003
On node 0 totalpages: 4096
zone(0): 4096 pages.
zone(1): 0 pages.
zone(2): 0 pages.
CPU: MICROBLAZE
Console: xmbserial on UARTLite
Kernel command line: 
Calibrating delay loop... 3.18 BogoMIPS
Memory: 14936K/16384K available (727K kernel code, 205K data)
Dentry cache hash table entries: 2048 (order: 2, 16384 bytes)
Inode cache hash table entries: 1024 (order: 1, 8192 bytes)
Mount cache hash table entries: 512 (order: 0, 4096 bytes)
Buffer-cache hash table entries: 1024 (order: 0, 4096 bytes)
Page-cache hash table entries: 4096 (order: 2, 16384 bytes)
POSIX conformance testing by UNIFIX
Linux NET4.0 for Linux 2.4
Based upon Swansea University Computer Society NET3.039
Microblaze UARTlite serial driver version 1.00
ttyS0 at 0xffff2000 (irq = 1) is a Microblaze UARTlite
ttyS1 at 0xffff4000 (irq = 2) is a Microblaze UARTlite
Starting kswapd
JFFS2 version 2.1. (C) 2001 Red Hat, Inc., designed by Axis Communications AB.
RAMDISK driver initialized: 16 RAM disks of 4096K size 1024 blocksize
MBVanilla flash probe(0xff000000,8388608,4): 800000 at ff000000
 Amd/Fujitsu Extended Query Table v1.1 at 0x0040
number of CFI chips: 1
cfi_cmdset_0002: Disabling fast programming due to code brokenness.
Creating 8 MTD partitions on "Flash":
0x00000000-0x00020000 : "Bootloader"
0x00020000-0x00040000 : "Bootargs"
0x00040000-0x00060000 : "MAC"
0x00080000-0x00100000 : "Config"
0x00060000-0x00080000 : "Spare"
0x00100000-0x00300000 : "Image"
0x00300000-0x00800000 : "JFFS2"
0x00000000-0x00800000 : "Flash"
MBVanilla ram probe(0x800ea698,344064,4): 54000 at 800ea698
Creating 1 MTD partitions on "RAM":
0x00000000-0x00054000 : "Romfs"
blk: queue 800dddc0, I/O limit 0Mb (mask 0x0)
magics are 90A5, a590
jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x00000000: 0x2d72 instead
jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x00000004: 0x3166 instead
jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x00000008: 0x0005 instead
jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x0000000c: 0x72e0 instead
jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x00000010: 0x524f instead
jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x00000014: 0x6973 instead
jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x0000002c: 0xd1ff instead
jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x00000030: 0x2e00 instead
jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x0000004c: 0xd1d1 instead
jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x00000050: 0x2e2e instead
Further such events for this erase block will not be printed
JFFS2: Erase block at 0x00000000 is not formatted. It will be erased
jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x00001000: 0xeac1 instead
jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x00001004: 0xc9e0 instead

[snip]

jffs2_scan_empty(): Empty block at 0x000530a8 ends at 0x00053134 (with 0xff000012)! Marking dirty
jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x00053134: 0xff00 instead
jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x00053138: 0x2200 instead
Further such events for this erase block will not be printed
JFFS2: Erase block at 0x00053000 is not formatted. It will be erased
Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes
VFS: Mounted root (romfs filesystem) readonly.
Freeing unused kernel memory: 36K freed

Sash command shell (version 1.1.1)
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