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From: Sergei Shtylyov <sshtylyov@ru.mvista.com>
To: Kumar Gala <galak@kernel.crashing.org>
Cc: Tejun Heo <htejun@gmail.com>,
	linux-ide@vger.kernel.org, gregkh@suse.de,
	linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org,
	jgarzik@pobox.com, alan@lxorguk.ukuu.org.uk
Subject: Re: [PATCH 6/13] devres: implement managed iomap interface
Date: Thu, 10 Apr 2008 22:24:54 +0400	[thread overview]
Message-ID: <47FE5B76.40409@ru.mvista.com> (raw)
In-Reply-To: <59A939C7-75AF-4C0F-8199-4C31D174AEA9@kernel.crashing.org>

Kumar Gala wrote:

>>>>>   Those functions are going to break on 32-bit platforms with  
>>>>> extended physical address (well, that's starting with Pentiums  
>>>>> which had 36-bit PAE :-) AND devices mapped beyond 4 GB (e.g.  
>>>>> PowerPC 44x).  You should have used resource_size_t for the  
>>>>> 'offset' parameter. As this most probably means that libata is  
>>>>> broken on such platforms, I'm going to submit a patch...

>>>   It's broken with drivers using MMIO, I meant to say.

>>   Oops, I meant PCI drivers here, at least for the time being. And  it 
>> looks like that was a false alarm. :-]

>>>> Yeah, right please go ahead.  But I wonder whether any BIOS was  
>>>> actually crazy enough to map mmio region above 4G on 32bit machine.

>>>   This is a *hardware* mapping on some non-x86 platforms (like PPC  
>>> 44x or MIPS Alchemy). The arch/ppc/ and arch/mips/ kernels have  
>>> special hooks called from ioremap() which help create an illusion  
>>> that the PCI memory space on such platforms (not only it) is mapped  
>>> below 4 GB; arch/powerpc/ kernel doesn't do this anymore -- hence  
>>> this newly encountered issue.

>>   I thought that pcim_iomap() used devm_ioremap() or something --  
>> which of course turned to be wrong. devm_ioremap() alone is yet safe  
>> since there are no users for it amongst PPC 44x platform device  
>> drivers...

> but there is no reason not to make it work properly.  For example I  
> believe libata uses devm_* and the fsl SATA driver (non-PCI) will need  
> to work in cases similar to the 44x.

    Well, as for sata_fsl, it calls of_iomap() which does The Right Thing.

> - k

WBR, Sergei

  reply	other threads:[~2008-04-10 18:26 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-01-10  5:35 [PATCHSET] Managed device resources, take #2 Tejun Heo
2007-01-10  5:35 ` [PATCH 2/13] devres: implement managed IO region interface Tejun Heo
2007-01-10  5:35 ` [PATCH 1/13] devres: device resource management core Tejun Heo
2007-01-10  5:35 ` [PATCH 3/13] devres: implement managed IRQ interface Tejun Heo
2007-01-10  5:35 ` [PATCH 4/13] devres: implement managed DMA interface Tejun Heo
2007-01-10  5:35 ` [PATCH 8/13] libata: implement ata_host_detach() Tejun Heo
2007-01-10  5:35 ` [PATCH 5/13] devres: implement managed PCI interface Tejun Heo
2007-01-10  5:35 ` [PATCH 6/13] devres: implement managed iomap interface Tejun Heo
2008-04-07 16:46   ` Sergei Shtylyov
2008-04-08 14:48     ` Tejun Heo
2008-04-08 14:55       ` Sergei Shtylyov
2008-04-08 15:03         ` Tejun Heo
2008-04-10 16:56         ` Sergei Shtylyov
2008-04-10 17:44           ` Kumar Gala
2008-04-10 18:24             ` Sergei Shtylyov [this message]
2008-04-10 19:40               ` Kumar Gala
2008-04-11  2:08                 ` Tejun Heo
2007-01-10  5:35 ` [PATCH 7/13] devres: add Documentation/driver-model/devres.txt Tejun Heo
2007-01-10  5:35 ` [PATCH 9/13] libata: update libata core layer to use devres Tejun Heo
2007-01-10  5:35 ` [PATCH 12/13] devres: implement pcim_iomap_regions() Tejun Heo
2007-01-10  5:35 ` [PATCH 11/13] libata: remove unused functions Tejun Heo
2007-01-20  0:31 ` [PATCHSET] Managed device resources, take #2 Jeff Garzik

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