[RFC PATCH 00/12] Ion cleanup in preparation for moving out of staging

Laurent Pinchart
2017-03-03T16:45:40Z

Hi Daniel,

On Friday 03 Mar 2017 11:04:33 Daniel Vetter wrote:
> On Thu, Mar 02, 2017 at 01:44:32PM -0800, Laura Abbott wrote:
> > Hi,
> >
> > There's been some recent discussions[1] about Ion-like frameworks. There's
> > apparently interest in just keeping Ion since it works reasonablly well.
> > This series does what should be the final clean ups for it to possibly be
> > moved out of staging.
> >
> > This includes the following:
> > - Some general clean up and removal of features that never got a lot of
> > use as far as I can tell.
> >
> > - Fixing up the caching. This is the series I proposed back in December[2]
> > but never heard any feedback on. It will certainly break existing
> > applications that rely on the implicit caching. I'd rather make an
> > effort to move to a model that isn't going directly against the
> > establishement though.
> >
> > - Fixing up the platform support. The devicetree approach was never well
> > recieved by DT maintainers. The proposal here is to think of Ion less as
> > specifying requirements and more of a framework for exposing memory to
> > userspace.
> >
> > - CMA allocations now happen without the need of a dummy device structure.
> > This fixes a bunch of the reasons why I attempted to add devicetree
> > support before.
> >
> > I've had problems getting feedback in the past so if I don't hear any
> > major objections I'm going to send out with the RFC dropped to be picked
> > up. The only reason there isn't a patch to come out of staging is to
> > discuss any other changes to the ABI people might want. Once this comes
> > out of staging, I really don't want to mess with the ABI.
> >
> > Feedback appreciated.
>
> Imo looks all good. And I just realized that cross-checking with the TODO,
> the 2 items about _CUSTOM and _IMPORT ioctls I noted are already there.
>
> Otherwise I looked through the patches, looks all really reasonable.

Two more items that need to be addressed in my opinion :

- Let's not export the ion_client API, we don't want drivers to be ion-
specific. Only the dma-buf interface should be visible to drivers.

- I haven't seen any proposal how a heap-based solution could be used in a
generic distribution. This needs to be figured out before committing to any
API/ABI.

> Wrt merging, my experience from destaging the android syncpt stuff was
> that merging the patches through the staging tree lead to lots of
> cross-tree issues with the gpu folks wanting to use that. Ion will
> probably run into similar things, so I'd propose we pull these cleanup
> patches and the eventual de-staging in throught drm. Yes that defacto
> means I'm also volunteering myself a bit :-)
>
> In the end we could put it all into drivers/gpu/ion or something like
> that.
>
> Thoughts? Greg?
> -Daniel
>
> > Thanks,
> > Laura
> >
> > [1] https://marc.info/?l=linux-kernel&m=148699712602105&w=2
> > [2] https://marc.info/?l=linaro-mm-sig&m=148176050802908&w=2
> >
> > Laura Abbott (12):
> > staging: android: ion: Remove dmap_cnt
> > staging: android: ion: Remove alignment from allocation field
> > staging: android: ion: Duplicate sg_table
> > staging: android: ion: Call dma_map_sg for syncing and mapping
> > staging: android: ion: Remove page faulting support
> > staging: android: ion: Remove crufty cache support
> > staging: android: ion: Remove old platform support
> > cma: Store a name in the cma structure
> > cma: Introduce cma_for_each_area
> > staging: android: ion: Use CMA APIs directly
> > staging: android: ion: Make Ion heaps selectable
> > staging; android: ion: Enumerate all available heaps
> >
> > drivers/base/dma-contiguous.c | 5 +-
> > drivers/staging/android/ion/Kconfig | 51 ++--
> > drivers/staging/android/ion/Makefile | 14 +-
> > drivers/staging/android/ion/hisilicon/Kconfig | 5 -
> > drivers/staging/android/ion/hisilicon/Makefile | 1 -
> > drivers/staging/android/ion/hisilicon/hi6220_ion.c | 113 ---------
> > drivers/staging/android/ion/ion-ioctl.c | 6 -
> > drivers/staging/android/ion/ion.c | 282
> > ++++++--------------- drivers/staging/android/ion/ion.h
> > | 5 +-
> > drivers/staging/android/ion/ion_carveout_heap.c | 16 +-
> > drivers/staging/android/ion/ion_chunk_heap.c | 15 +-
> > drivers/staging/android/ion/ion_cma_heap.c | 102 ++------
> > drivers/staging/android/ion/ion_dummy_driver.c | 156 ------------
> > drivers/staging/android/ion/ion_enumerate.c | 89 +++++++
> > drivers/staging/android/ion/ion_of.c | 184 --------------
> > drivers/staging/android/ion/ion_of.h | 37 ---
> > drivers/staging/android/ion/ion_page_pool.c | 3 -
> > drivers/staging/android/ion/ion_priv.h | 57 ++++-
> > drivers/staging/android/ion/ion_system_heap.c | 14 +-
> > drivers/staging/android/ion/tegra/Makefile | 1 -
> > drivers/staging/android/ion/tegra/tegra_ion.c | 80 ------
> > include/linux/cma.h | 6 +-
> > mm/cma.c | 25 +-
> > mm/cma.h | 1 +
> > mm/cma_debug.c | 2 +-
> > 25 files changed, 312 insertions(+), 958 deletions(-)
> > delete mode 100644 drivers/staging/android/ion/hisilicon/Kconfig
> > delete mode 100644 drivers/staging/android/ion/hisilicon/Makefile
> > delete mode 100644 drivers/staging/android/ion/hisilicon/hi6220_ion.c
> > delete mode 100644 drivers/staging/android/ion/ion_dummy_driver.c
> > create mode 100644 drivers/staging/android/ion/ion_enumerate.c
> > delete mode 100644 drivers/staging/android/ion/ion_of.c
> > delete mode 100644 drivers/staging/android/ion/ion_of.h
> > delete mode 100644 drivers/staging/android/ion/tegra/Makefile
> > delete mode 100644 drivers/staging/android/ion/tegra/tegra_ion.c

--
Regards,

Laurent Pinchart