[PATCH 0/6+1] ARM: EXYNOS4: SYSMMU: Improvements on SYSMMU driver

KyongHo Cho pullip.cho at samsung.com
Mon Jul 4 19:38:17 EDT 2011


Hi.
On Mon, Jul 4, 2011 at 3:47 PM, Marek Szyprowski
<m.szyprowski at samsung.com> wrote:
> Hello,
>
> I really don't get why do You persist in creating one monster platform
> device with resources for ALL SYSMMU/IOMMU controllers that are available
> on Exynos4 CPU. We (SPRC, see Andrzej's SYSMMU patches) already proposed
> a clean solution for making the SYSMMU controllers independent of each
> other as well as making the main SYSMMU driver simpler and more
> independent of the particular Exynos4 platform definition. In Linux
> device model if the device/controller exist in the system in more than
> one instance, there should by one generic driver for it and a set of
> platform definitions for each instance.
>
Did you find this patch? "[PATCH 3/6] ARM: EXYNOS4: SYSMMU"
I Cced you because it includes your suggestion.

> Here is the link to our SYSMMU updated driver (implementing common
> iommu API):
> http://www.spinics.net/lists/linux-samsung-soc/msg04508.html
> The driver still needs some cleanup, but this has been delayed until
> the dma-mapping framework update is finished.
>
> I also don't get why do you want to keep the completely custom sysmmu
> driver and implement iommu API on top of it. Is it really required for
> anything? Mainline kernel is not a place for custom APIs if there is
> already a common, generic one.

I did not exposed any custom API.
The global function in the last patch is just for IOMMU API implemenation.
The header file in the last patch is not for the device drivers but
for the IOMMU API implementation.
Actually, they can be merged into one single file.
But I just wanted to change the kernel code stepwise.



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