[microblaze-uclinux] Re: Re: [uClinux-dev] using flashw

[anand_12 <anand_12@xxxxxxxxxxxx>]

Hi john,

 Yes..I disabled 'blkmem' and everything is fine now..
and now I know much more than what I knew yesterday about
this 'blkmem v/s MTD' thing..thanks..:-)..actually I also enabled one more option which was not enabled by default
..that is under kernel config -> MTD -> read-only block access to MTD devices...this particular option was not enabled by default..i got the information from some earlier postings about this...once i enabled this option and included support for AMD/Fujitsu FLASH chips( 
kernel config -> MTD -> RAM/ROM/FLASH chip drivers -> Support for AMD/Fujitsu flash chips)...the kernel was 
able to create MTD partitions on the FLASH chip...

Now I guess I should be able to program the FLASH using flashw without much problems..:-)..


Regards

V.Anand










Hi Anand,
>
>anand_12 wrote:
>
>>  Thanks a lot for your clarification..well..thats precisely the information I was hunting for..I keep getting this
>> error/message "can't allocate major number 31 to....."
>> ..now I know why that is happening..well otherwise..I have verified the flash partitions..they are getting created properly..atleast thats what i assume from this kernel bootlog :
>> 
>
>> Blkmem copyright 1998,1999 D. Jeff Dionne
>> Blkmem copyright 1998 Kenneth Albanowski
>> Blkmem 1 disk images:
>> 0: 8014CA10-80188E0F [VIRTUAL 8014CA10-80188E0F] (RO)
>
>Here the blkmem driver is taking responsibility for the romfs...
>
>> uclinux[mtd]: RAM probe address=0x8014ca10 size=0x3d000
>> uclinux[mtd]: root filesystem index=0
>> MBVanilla flash probe(0xff000000,
>>  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(0x8014ca10,249856,4): 3d000 at 8014ca10
>> Creating 1 MTD partitions on "RAM":
>> 0x00000000-0x0003d000 : "Romfs"
>
>And here MTD is attempting to do the same (as well as create flash 
>partitions).  This is bad.
>
>> Can't allocate major number 31 for Memory Technology Devices.
>
>And here is the MTD driver complaining about driver major number being 
>already taken (by blkmem).
>
>You should just disable the blkmem driver in the kernel config, and 
>rebuild the kernel.  I expect that will fix the problem immediately.
>
>Arguments on blkmem vs MTD go something like this:
>
>blkmem is simple, lightweight and it works.  However, configuring it is 
>a mess of hacking on header files and so on.  blkmem is slowly dying 
>(not sure if it's in 2.6)
>
>MTD is also simple, and it works, with I think very slightly larger 
>overhead (code footprint).  However, configuring it for a new platform 
>is a breeze.  MTD is alive and well, widely used outside the NOMMU 
>community.
>
>I switched the default microblaze configuration over to MTD about 12 
>months ago, and it is enabled by default in the mbvanilla_net platform. 
>  Unless you have compelling reasons to do otherwise, I'd recommend you 
>just go with MTD.
>
>Regards,
>
>John
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>
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