Re: [PATCH4/4] [POWERPC] Fix cpm_uart driver

[Scott Wood <scottwood@freescale.com>]

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/