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

From: Scott Wood
Date: Mon Sep 24 2007 - 14:22:49 EST

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

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. :-)

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