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Re: [PATCH] fix PCI-memory access on Alchemy Au15x0

To: Alexander Bigga <ab@mycable.de>
Subject: Re: [PATCH] fix PCI-memory access on Alchemy Au15x0
From: Ralf Baechle <ralf@linux-mips.org>
Date: Wed, 10 Jan 2007 19:52:38 +0000
Cc: linux-mips@linux-mips.org
In-reply-to: <20061221102519.GA11796@mycable-alex>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <20061221102519.GA11796@mycable-alex>
Sender: linux-mips-bounce@linux-mips.org
User-agent: Mutt/1.4.2.2i
On Thu, Dec 21, 2006 at 11:25:19AM +0100, Alexander Bigga wrote:

> The problem was introduced in 2.6.18.3 with the casting of some 36bit-defines
> (PCI memory) in au1000.h to resource_size_t which may be u32 or u64 depending 
> on
> the experimental CONFIG_RESOURCES_64BIT.
> 
> With unset CONFIG_RESOURCES_64BIT, the pci-memory cannot be accessed because
> the ioremap in arch/mips/au1000/common/pci.c already used the truncated
> addresses.
> With set CONFIG_RESOURCES_64BIT, things get even worse, because PCI-scan
> aborts, due to resource conflict: request_resource() in arch/mips/pci/pci.c
> fails because the maximum iomem-address is 0xffffffff (32bit) but the
> pci-memory-start-address is 0x440000000 (36bit).
> 
> To get pci working again, I propose the following patch:
> 
> 1. remove the resource_size_t-casting from au1000.h again
> 2. make the casting in arch/mips/au1000/common/pci.c (it's allowed and
> necessary here. The 36bit-handling will be done in __fixup_bigphys_addr).
> 
> With this patch pci works again like in 2.6.18.2, the gcc-compile warnings
> in pci.c are gone and it doesn't depend on CONFIG_EXPERIMENTAL.
> 
> Only advantages ;-) Nevertheless, I'm open for your comments or even better
> solutions.

Looks reasonable, applied.

  Ralf

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