lkml.org 
[lkml]   [2007]   [Sep]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH4/4] [POWERPC] Fix cpm_uart driver
Jochen Friedrich wrote:
> Scott Wood schrieb:
>> Jochen Friedrich wrote:
>>>
>>> In cpm_uart_core, functions cpm_uart_init_bd and cpm_uart_init_scc
>>> an offset into DP RAM is calculated by substracting a physical
>>> memory constant from an virtual address. This patch fixes the
>>> problem by converting the virtual address into a physical
>>> first.
>>
>> Huh? DPRAM_BASE is a virtual address. With this patch, you'd be
>> subtracting a virtual address from a physical address.
>
> Thanks for pointing me to it. So the bug is in cpm_uart_cpm1.h assigning
> a physical memory to DPRAM_BASE (at least on ARC=ppc). cpm_uart_cpm2.h
> seems to be correct though. I'll submit a new patch for this.

cpmp is a physical address on arch/ppc?
/me looks at arch/ppc/8xx_io/commproc.c

Yikes. Please don't change cpm_uart_cpm1.h, as it's correct for
arch/powerpc, and there are numerous other places that assume cpmp is
virtual (including in the very same function that assigns it a physical
address).

You could fix arch/ppc if you want, though it may be easier to wait for
it to die, and insist on identity maps in the meantime. :-)

-Scott
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-09-24 20:25    [W:0.055 / U:0.488 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site