Re: mkfs.jffs2

[Narinder Kumar <narinder@kritikalsolutions.com>]

Andrew Victor wrote:

>hi,
>
>  
>
>>       First of all thanx for the reply . I am using AT45DB642 NAND 
>>Flash and it seems to have erase block of 0x420 i,e 1056 bytes. and when 
>>i have created my MTD partitions i have specified the partition sizes to 
>>be multiple of these eraseblock sizes in 
>>drivers/at91/mtd/at91_dataflash.c , My 3 partitions are 4*1024*1056  (4 
>>GB) , 3*1024*1056 (3 GB) and 1*1024*1056 (1 GB)
>>    
>>
>
>Atmel AT45DB642 is DataFlash (not NAND).
>mkfs.jffs2 is currently broken for DataFlash.
>
>This is how I once fixed it.  I don't know if the current mkfs.jffs2
>code is different.....
>
>In mkfs.jffs2.c in function main().  Comment out the code:
>
>//     /* If it's less than 4096, assume they meant KiB */
>//     if (erase_block_size && erase_block_size < 0x1000)
>//         erase_block_size *= 1024;
>//     /* If it's less than 8KiB, they're not allowed */
>//     if (erase_block_size < 0x2000) {
>//         fprintf(stderr, "Increasing erase size to 8KiB minimum\n");
>//         erase_block_size = 0x2000;
>//     }
>
>Then run mkfs.jffs2 with the parameters "-e 2112 -n -l"
>
>The 2112 is because JFFS2 merges multiple 528-byte or 1056-byte physical
>blocks into larger virtual blocks.
>The 2112 is for a 4Mb dataflash device, and that value will probably
>differ for differently sized dataflash devices.
>
>You should see the message:
>  JFFS2 write-buffering enabled (2112)
>when you mount the JFFS2 partition.  The size of brackets is the virtual
>blocks size.  You should also be using the code from the MTD/JFFS2 CVS.
>
>
>Regards,
>  Andrew Victor
>  SAN People (Pty) Ltd.
>
>
>
>
>
>  
>
I tried out the solution that you mentioned but it doesn't seems to work 
for me. I am using ATMEL AT45DB642 which is an 8MB Dataflash. Can anyone 
tell me what the erase size of this DataFlash. Currently i am trying out 
with 1056 ( i,e 0x420 in hex) . If anyone has success in making a jffs2 
partition on this dataflash and thereby reading/writing on it, please 
help me out. I tried out with different erasesizes but it doesn't seems 
to work.

                Can anyone tell me what are the parameters to be 
specified in drivers/at91/mtd/at91_dataflash.c where one can specify 
what static partitions are to be created in the data flash. I am 
currenlt giving
static struct mtd_partition static_partitions[] =
{
        {
                name:           "bootloader",
                offset:         0,
                size:           1 * 1024 * 1056,        // 1 MB
                mask_flags:     MTD_WRITEABLE           // read-only
        },
        {
                name:           "kernel",
                offset:         MTDPART_OFS_NXTBLK,
                size:           1 * 1024 * 1056,        // 1 MB
        },
        {
                name:           "ramdisk",
                offset:         MTDPART_OFS_NXTBLK,
                size:           3 * 1024 * 1056,        // 3 MB
        },
        {
                name:           "Application",
                offset:         MTDPART_OFS_NXTBLK,
                size:           MTDPART_SIZ_FULL,
        }
};

         Am i write on these parameters ?

Regards,
 Narinder
 KSPL, Delhi