"kernel access of bad area" while accessing flash

"kernel access of bad area" while accessing flash

[Fundu]

I have a PPC440GX based board.

Do I need to reinitialize Peripheral Bank Configuration Registers (EBC0_B0CR-EBC0_B7CR) from the kernel ?
I'm quite sure that we don't, but just want to make sure. Because the problem
that i'm seeing strongly suggest that it's probably not accessible. 

Here's the problem, i'm getting "kernel access of bad
 area" when i erase any of the upper 64mb out of 128mb flash region, surprisingly i can easily erase (all of the flash) from u-boot. which makes me ask the earlier question.   

any insights welcome.

thanks ! 


      

Re: "kernel access of bad area" while accessing flash

[Josh Boyer]

On Tue, Aug 26, 2008 at 08:13:39PM -0700, Fundu wrote:
>I have a PPC440GX based board.
>
>Do I need to reinitialize Peripheral Bank Configuration Registers (EBC0_B0CR-EBC0_B7CR) from the kernel ?
>I'm quite sure that we don't, but just want to make sure. Because the problem
>that i'm seeing strongly suggest that it's probably not accessible. 

Typically not.  The kernel tends to rely on the EBC registers being properly
programmed by the bootloader/firmware for the devices contained in it's banks.

>Here's the problem, i'm getting "kernel access of bad
> area" when i erase any of the upper 64mb out of 128mb flash region, surprisingly i can easily erase (all of the flash) from u-boot. which makes me ask the earlier question.   
>

That sounds more like a mapping issue than an EBC config issue.  Make sure
the kernel is calling ioremap on the entire flash memory region.

josh