[PATCH 0/7] [RFC] drm/exynos: Add IOMMU support to DRM

[Prathyush K]

The dma-mapping framework needs a IOMMU mapping to be created for the
device which allocates/maps/frees the non-contig buffer. In the DRM
framework, a gem buffer is created by the DRM virtual device and not
directly by any of the physical devices (FIMD, HDMI etc). Each gem object
can be set as a framebuffer to one or many of the drm devices. So a gem
object cannot be allocated for any one device. All the DRM devices should
be able to access this buffer.

The proposed method is to create a common IOMMU mapping during drm init. This
mapping is then attached to all of the drm devices including the drm device.
[PATCH 1/7] drm/exynos: create common IOMMU mapping for DRM

During the probe of drm fimd, the driver retrieves a 'sysmmu' field
in the device node for fimd. If such a field exists, the driver retrieves the
platform device of the sysmmu device. This sysmmu is set as the sysmmu
for fimd. The common mapping created is then attached to fimd.
This needs to be done for all the other devices (hdmi, vidi etc).
[PATCH 2/7] ARM: EXYNOS5: add sysmmu field to fimd device node
[PATCH 3/7] drm/exynos: add IOMMU support to drm fimd

During DRM's probe which happens last, the common mapping is set to its archdata
and iommu ops are set as its dma ops. This requires a modification in the
dma-mapping framework so that the iommu ops can be visible to all drivers.
[PATCH 4/7] ARM: dma-mapping: rename and export iommu_ops
[PATCH 5/7] drm/exynos: attach drm device with common drm mapping

Currently allocation and free use the iommu framework by calling
dma_alloc_writecombine and dma_free_writecombine respectively.
For mapping the buffers to user space, the mmap functions assume that
the buffer is contiguous. This is modified by calling dma_mmap_writecombine.
[PATCH 6/7] drm/exynos: Add exynos drm specific fb_mmap function
[PATCH 7/7] Add IOMMU support for mapping gem object

The device tree based patches are based on Leela's patch which was posted
last week for adding DT support to DRM FIMD. The patch to add sysmmu
field is for reference only and will be posted to the device tree
mailing list. Same with the rename and export iommu_ops patch.

These patches are tested on Exynos5250 SMDK board and tested with modetest
from libdrm tests.

Prathyush K (7):
  drm/exynos: create common IOMMU mapping for DRM
  ARM: EXYNOS5: add sysmmu field to fimd device node
  drm/exynos: add IOMMU support to drm fimd
  ARM: dma-mapping: rename and export iommu_ops
  drm/exynos: attach drm device with common drm mapping
  drm/exynos: Add exynos drm specific fb_mmap function
  drm/exynos: Add IOMMU support for mapping gem object

 arch/arm/boot/dts/exynos5250.dtsi         |    1 +
 arch/arm/include/asm/dma-mapping.h        |    1 +
 arch/arm/mm/dma-mapping.c                 |    5 ++-
 drivers/gpu/drm/exynos/exynos_drm_core.c  |    3 ++
 drivers/gpu/drm/exynos/exynos_drm_drv.c   |   30 ++++++++++++++++
 drivers/gpu/drm/exynos/exynos_drm_drv.h   |   10 +++++
 drivers/gpu/drm/exynos/exynos_drm_fbdev.c |   16 ++++++++
 drivers/gpu/drm/exynos/exynos_drm_fimd.c  |   54 ++++++++++++++++++++++++++++-
 drivers/gpu/drm/exynos/exynos_drm_gem.c   |   35 ++++++++----------
 9 files changed, 133 insertions(+), 22 deletions(-)