[PATCH 00/18] Clean up exposure of arch-internal code

[Heiko Stübner]

Am Montag, 27. Juli 2015, 15:13:13 schrieb Joerg Roedel:
> [+ Heiko for comment on Rockchip IOMMU]

adding also Daniel Kurtz and Tomasz Figa who did most of the iommu stuff if I 
remember correctly.


While I'm not this versed in the iommu world I see the issue Russell pointed 
out, as especially the cache flushes won't work like this on arm64, which uses 
the same iommu on the rk3368.


I'll also try to understand what this does and what needs to be done to the 
Rockchip iommu, but I guess that'll still take a bit.


> On Mon, Jul 27, 2015 at 01:28:24PM +0100, Russell King - ARM Linux wrote:
> > This series of patches attempts to clean up the use of architecture
> > internal functions in drivers, and removes some functions from view
> > in the asm/ headers.  I'm also considering whether we need to add
> > some linker magic to hide symbols when building the built-in.o files.
> > 
> > This was triggered by 3rd party drivers "going under the covers" of
> > the DMA API and calling the dmac_*() functions directly, a practice
> > which I have always refused to allow.  This also breaks module
> > building (which is the big hint that they're doing something wrong.)
> > 
> > However, it also came to light that various drivers are using
> > __cpuc_* functions directly, which are non-portable, and is another
> > instance of "going under the covers" and tinkering with what should
> > be kept as architecture implementation details.
> > 
> > This series addresses some of these points.  It:
> > 
> > (a) moves dmac_map_area() and dmac_unmap_area() prototypes out of
> > 
> >     asm/cacheflush.h and into arch/arm/mm.
> > 
> > (b) provide a secure_flush() call for the Qualcomm secure monitor
> > 
> >     code.
> > 
> > (c) stop tegra smmu driver(s) from using __cpuc_flush_dcache_area,
> > 
> >     something which necessitates additional complexity to deal with
> >     the ARM vs ARM64 differences.  It should be using the DMA API.
> >     However, the Tegra SMMU driver is in really bad shape, and this
> >     isn't a simple conversion - it requires a lot of additional
> >     fixes to bring the code up to scratch.
> > 
> > It leaves the Rockchip IOMMU driver for the time being, but that is also
> > something which needs cleaning up in the same way as the Tegra SMMU
> > driver.
> > 
> >  arch/arm/include/asm/cacheflush.h |  21 ++-
> >  arch/arm/include/asm/glue-cache.h |   2 -
> >  arch/arm/mm/dma-mapping.c         |   1 +
> >  arch/arm/mm/dma.h                 |  32 ++++
> >  drivers/firmware/qcom_scm-32.c    |   4 +-
> >  drivers/iommu/tegra-smmu.c        | 297
> >  ++++++++++++++++++++++++-------------- drivers/memory/tegra/tegra114.c  
> >  |  17 ---
> >  drivers/memory/tegra/tegra124.c   |  30 ----
> >  drivers/memory/tegra/tegra30.c    |  17 ---
> >  include/soc/tegra/mc.h            |   7 -
> >  10 files changed, 242 insertions(+), 186 deletions(-)