On 07/13/2012 12:09 PM, Inki Dae wrote:
-----Original Message-----
From: Prathyush K [mailto:prathyush.k@xxxxxxxxxxx]
Sent: Wednesday, July 11, 2012 6:40 PM
To: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Cc: prathyush@xxxxxxxxxxxx; m.szyprowski@xxxxxxxxxxx;
inki.dae@xxxxxxxxxxx;
subash.ramaswamy@xxxxxxxxxx
Subject: [PATCH 0/7] [RFC] drm/exynos: Add IOMMU support to DRM
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.
It's good to use unified iommu table so I agree to your opinion but we don't
decide whether we use dma mapping api or not. now dma mapping api has one
issue.
in case of using iommu with dma mapping api, we couldn't use physically
contiguous memory region with iommu. for this, there is a case that we
should use physically contiguous memory region with iommu. it is because we
sometime may use mfc(hw video codec) with secure zone such as ARM TrustZone.
Then, it needs physically contiguous memory region.
Thanks,
Inki Dae
I agree. In the mainline code, as of now only the arm_dma_ops has the
support allocating
from the CMA. But in the function arm_iommu_alloc_attrs(), there is no
way to know if the
device had declared a contiguous memory range. The reason, we don't
store that cookie
into the device during the dma_declare_contiguous(). So is it advisable
to store such information
like mapping(in the iommu operations) in the device.archdata?
Regards,
Subash
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(-)
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