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Re: cache coherency in DMA and MMIO
From: |
Samuel Thibault |
Subject: |
Re: cache coherency in DMA and MMIO |
Date: |
Thu, 22 Apr 2010 17:01:50 +0200 |
User-agent: |
Mutt/1.5.12-2006-07-14 |
Samuel Thibault, le Thu 22 Apr 2010 16:51:38 +0200, a écrit :
> Da Zheng, le Thu 22 Apr 2010 22:37:51 +0800, a écrit :
> > So does the driver need to consider about cache coherency problems on PC
> > when
> > interacting with the external device?
>
> Yes (since you can not rely on the BIOS), you need to remap the mmio
> range with cache disabled: INTEL_PTE_NCACHE|INTEL_PTE_WTHRU. This should
> already be done by pmap_enter().
And you need to access it using the volatile qualifier.
Samuel
- cache coherency in DMA and MMIO, Da Zheng, 2010/04/22
- Re: cache coherency in DMA and MMIO, Samuel Thibault, 2010/04/22
- Re: cache coherency in DMA and MMIO,
Samuel Thibault <=
- Re: cache coherency in DMA and MMIO, Da Zheng, 2010/04/23
- Re: cache coherency in DMA and MMIO, Samuel Thibault, 2010/04/23
- Re: cache coherency in DMA and MMIO, Da Zheng, 2010/04/24
- Re: cache coherency in DMA and MMIO, Samuel Thibault, 2010/04/24
- Re: cache coherency in DMA and MMIO, Da Zheng, 2010/04/24
- Re: cache coherency in DMA and MMIO, Samuel Thibault, 2010/04/24