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Re: cache coherency in DMA and MMIO
From: |
Samuel Thibault |
Subject: |
Re: cache coherency in DMA and MMIO |
Date: |
Fri, 23 Apr 2010 13:37:48 +0200 |
User-agent: |
Mutt/1.5.12-2006-07-14 |
Da Zheng, le Fri 23 Apr 2010 14:51:22 +0800, a écrit :
> They are not just one or two variables. They are an array of structure
> variables. Should I define all fields of the structure with volatile
> qualifier?
You can qualify the whole structure
> It's strange. The Linux driver doesn't do so but it definitely works in the
> Linux kernel.
It does (or should do): such pointers have the __io qualifier.
> I use the mem device to allocate MMIO space. I guess INTEL_PTE_NCACHE and
> INTEL_PTE_WTHRU haven't been set to the MMIO pages, right?
Depends on how you use the mem device. It it ends up using pmap_enter()
to actually fill the page table, it will notice whether your physical
addresses are within RAM or above, see the code there.
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, 2010/04/22
- Re: cache coherency in DMA and MMIO, Da Zheng, 2010/04/23
- Re: cache coherency in DMA and MMIO,
Samuel Thibault <=
- 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