linux-kernel - Re: [PATCH] x86-64: disable the GART in shutdown v2

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Date:	Mon, 25 Jun 2007 12:52:48 -0700
From:	Yinghai Lu <Yinghai.Lu@....COM>
To:	Muli Ben-Yehuda <muli@...ibm.com>
Cc:	Andi Kleen <ak@...e.de>, Andrew Morton <akpm@...ux-foundation.org>,
	Alan Cox <alan@...rguk.ukuu.org.uk>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Vivek Goyal <vgoyal@...ibm.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86-64: disable the GART in shutdown v2

Muli Ben-Yehuda wrote:
>> diff --git a/arch/x86_64/kernel/pci-gart.c b/arch/x86_64/kernel/pci-gart.c
>> index ae091cd..6c4fe16 100644
>> --- a/arch/x86_64/kernel/pci-gart.c
>> +++ b/arch/x86_64/kernel/pci-gart.c
>> @@ -571,6 +571,27 @@ static const struct dma_mapping_ops gart_dma_ops = {
>>  	.unmap_sg = gart_unmap_sg,
>>  };
>>  
>> +void gart_iommu_shutdown(void)
>> +{
>> +	struct pci_dev *dev;
>> +	int i;
>> +
> 
> extra blank line
> 
>> +
>> +	if (noagp && (dma_ops != &gart_dma_ops))
>> +		return;
> 
> noagp? did you mean 'no_agp'?
> 
I will fix it.
>> +
>> +	for (i = 0; i < num_k8_northbridges; i++) {
>> +		u32 ctl;
>> +
>> +		dev = k8_northbridges[i];
>> +		pci_read_config_dword(dev, 0x90, &ctl);
>> +
>> +		ctl &= ~1;
>> +
>> +		pci_write_config_dword(dev, 0x90, ctl);
>> +	}
>> +}
>> +
>>  void __init gart_iommu_init(void)
>>  { 
>>  	struct agp_kern_info info;
>> diff --git a/arch/x86_64/kernel/pci-dma.c b/arch/x86_64/kernel/pci-dma.c
>> index 9f80aad..b406b54 100644
>> --- a/arch/x86_64/kernel/pci-dma.c
>> +++ b/arch/x86_64/kernel/pci-dma.c
>> @@ -322,6 +322,11 @@ static int __init pci_iommu_init(void)
>>  	return 0;
>>  }
>>  
>> +void pci_iommu_shutdown(void)
>> +{
>> +	gart_iommu_shutdown();
> 
> I really dislike this. Here's how this function is going to look in a
> few months:
> 
> void pci_iommu_shutdown(void)
> {
> 	gart_iommu_shutdown();
> 
> 	calgary_iommu_shutdown();
> 
> 	vtd_iommu_shutdown();
> 
> 	amd_iommu_shutdown();
> 
> 	/* etc, ad nauseam */
> }
> 
> Where all of these are no-ops, except one. Now what's wrong with this
> picture?
> 
>> diff --git a/include/asm-x86_64/proto.h b/include/asm-x86_64/proto.h
>> index 85255db..b70aa0c 100644
>> --- a/include/asm-x86_64/proto.h
>> +++ b/include/asm-x86_64/proto.h
>> @@ -85,11 +85,13 @@ extern int exception_trace;
>>  extern unsigned cpu_khz;
>>  extern unsigned tsc_khz;
>>  
>> +extern void pci_iommu_shutdown(void);
>>  extern void no_iommu_init(void);
>>  extern int force_iommu, no_iommu;
>>  extern int iommu_detected;
>>  #ifdef CONFIG_IOMMU
>>  extern void gart_iommu_init(void);
>> +extern void gart_iommu_shutdown(void);
>>  extern void __init gart_parse_options(char *);
>>  extern void iommu_hole_init(void);
>>  extern int fallback_aper_order;
>> @@ -101,6 +103,11 @@ extern int fix_aperture;
>>  #else
>>  #define iommu_aperture 0
>>  #define iommu_aperture_allowed 0
>> +
>> +static inline void gart_iommu_shutdown(void)
>> +{
>> +}
>> +
> 
> I suggest include/asm-x86_64/iommu.h for this. proto.h doesn't have
> anything to do with it.

move iommu releated to iommu.h and add iommu_ops struct?

YH
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