linux kernel can not find m25p80 mtdparts

linux kernel can not find m25p80 mtdparts

[Bharat Bhushan]

Hi Everyone,

I am naive as far as linux kernel interface with MTD devices. I face
difficulty on MIPS based board having M25P80. Bootloader is u-boot.
When linux boots, I pass the command-line argument as:

Kernel command line:
mtdpart=m25p80:256k(boot),64k(boot_config),64k(board_config),2048k(kernel),4096k(filesystem)
root=/dev/mtdpart rootfstype=squashfs,yaffg
And Error I get is :

    VFS: Cannot open root device "mtdpart" or unknown-block(0,0)
    Please append a correct "root=" boot option; here are the
available partitions:
    Kernel panic - not syncing: VFS: Unable to mount root fs on
unknown-block(0,0)

Some questions in above command-line I have:

1. Does kernel recognize m25p80 by same name. How can I check where it
is mapped in kernel. Then only mtdpart makes sense: I think so? I
expected it to be at 0xbf040000. I do not know in kernel where to find
this mapping. I tried drivers/mtd/ for chips specifics, but could not
make out much.
2. When cmdline say root=/dev/mtdpart, do `mtdpart' should be defined
in kernel somewhere?

Can someone please explain, which all part of kernel I need to look into.

Regards,
Bharat

Re: linux kernel can not find m25p80 mtdparts

[Matthieu CASTET]

Bharat Bhushan a écrit :
> Hi Everyone,
> 
> I am naive as far as linux kernel interface with MTD devices. I face
> difficulty on MIPS based board having M25P80. Bootloader is u-boot.
> When linux boots, I pass the command-line argument as:
> 
> Kernel command line:
> mtdpart=m25p80:256k(boot),64k(boot_config),64k(board_config),2048k(kernel),4096k(filesystem)
> root=/dev/mtdpart rootfstype=squashfs,yaffg
> And Error I get is :
> 
>     VFS: Cannot open root device "mtdpart" or unknown-block(0,0)
>     Please append a correct "root=" boot option; here are the
> available partitions:
>     Kernel panic - not syncing: VFS: Unable to mount root fs on
> unknown-block(0,0)
> 
> Some questions in above command-line I have:
> 
> 1. Does kernel recognize m25p80 by same name. How can I check where it
> is mapped in kernel. Then only mtdpart makes sense: I think so? I
> expected it to be at 0xbf040000. I do not know in kernel where to find
> this mapping. I tried drivers/mtd/ for chips specifics, but could not
> make out much.
> 2. When cmdline say root=/dev/mtdpart, do `mtdpart' should be defined
> in kernel somewhere?
> 
> Can someone please explain, which all part of kernel I need to look into.
> 

What's your spi driver ?