[PATCH v4] DRM: add drm gem CMA helper

[Laurent Pinchart]

Hi Dave,

On Thursday 09 August 2012 07:02:45 Dave Airlie wrote:
> On Thu, Aug 9, 2012 at 2:31 AM, Laurent Pinchart wrote:
> > On Wednesday 08 August 2012 18:25:30 Lars-Peter Clausen wrote:
> >> On 08/08/2012 04:44 PM, Laurent Pinchart wrote:
> >> > On Wednesday 27 June 2012 15:30:18 Sascha Hauer wrote:
> >> >> Many embedded drm devices do not have a IOMMU and no dedicated
> >> >> memory for graphics. These devices use CMA (Contiguous Memory
> >> >> Allocator) backed graphics memory. This patch provides helper
> >> >> functions to be able to share the code. The code technically does
> >> >> not depend on CMA as the backend allocator, the name has been chosen
> >> >> because cma makes for a nice, short but still descriptive function
> >> >> prefix.
> >> >> 
> >> >> Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
> >> >> ---
> >> >> 
> >> >> changes since v3:
> >> >> - *really* use DIV_ROUND_UP(args->width * args->bpp, 8) to calculate
> >> >> the
> >> >> pitch changes since v2:
> >> >> - make drm_gem_cma_create_with_handle static
> >> >> - use DIV_ROUND_UP(args->width * args->bpp, 8) to calculate the pitch
> >> >> - make drm_gem_cma_vm_ops const
> >> >> - add missing #include <linux/export.h>
> >> >> changes since v1:
> >> >> - map whole buffer at mmap time, not page by page at fault time
> >> >> - several cleanups as suggested by Lars-Peter Clausen and Laurent
> >> >> Pinchart
> >> >> 
> >> >>  drivers/gpu/drm/Kconfig              |    6 +
> >> >>  drivers/gpu/drm/Makefile             |    1 +
> >> >>  drivers/gpu/drm/drm_gem_cma_helper.c |  251
> >> >>  +++++++++++++++++++++++++++++++
> >> >>  include/drm/drm_gem_cma_helper.h     |   44 ++++++
> >> >>  4 files changed, 302 insertions(+)
> >> >>  create mode 100644 drivers/gpu/drm/drm_gem_cma_helper.c
> >> >>  create mode 100644 include/drm/drm_gem_cma_helper.h
> >> >> 
> >> >> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> >> >> index dc5df12..8f362ec 100644
> >> >> --- a/drivers/gpu/drm/Kconfig
> >> >> +++ b/drivers/gpu/drm/Kconfig
> >> >> @@ -53,6 +53,12 @@ config DRM_TTM
> >> >> 
> >> >>      GPU memory types. Will be enabled automatically if a device
> >> >>      driver
> >> >>      uses it.
> >> >> 
> >> >> +config DRM_GEM_CMA_HELPER
> >> >> +  tristate
> >> >> +  depends on DRM
> >> >> +  help
> >> >> +    Choose this if you need the GEM CMA helper functions
> >> >> +
> >> >> 
> >> >>  config DRM_TDFX
> >> >>  
> >> >>    tristate "3dfx Banshee/Voodoo3+"
> >> >>    depends on DRM && PCI
> >> >> 
> >> >> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> >> >> index 0487ff6..8759cda 100644
> >> >> --- a/drivers/gpu/drm/Makefile
> >> >> +++ b/drivers/gpu/drm/Makefile
> >> >> @@ -15,6 +15,7 @@ drm-y       :=   drm_auth.o drm_buffer.o drm_bufs.o
> >> >> drm_cache.o \ drm_trace_points.o drm_global.o drm_prime.o
> >> >> 
> >> >>  drm-$(CONFIG_COMPAT) += drm_ioc32.o
> >> >> 
> >> >> +drm-$(CONFIG_DRM_GEM_CMA_HELPER) += drm_gem_cma_helper.o
> >> > 
> >> > This results in a built failure for me with
> >> > 
> >> > CONFIG_DRM=y
> >> > CONFIG_DRM_KMS_HELPER=m
> >> > # CONFIG_DRM_LOAD_EDID_FIRMWARE is not set
> >> > CONFIG_DRM_GEM_CMA_HELPER=m
> >> > CONFIG_DRM_KMS_CMA_HELPER=m
> >> > 
> >> > drm_gem_cma_helper.o isn't compiled at all. Can you reproduce the
> >> > problem
> >> > ?
> >> 
> >> The Kconfig entry needs to be bool instead of tristate.
> > 
> > That's my preferred solution as well. I'll modify the patch in my tree,
> > unless Sascha wants to submit a v5.
> 
> Oh I keep missing this, I've no objections to putting it into -next,
> if someone sends one clean patch to the list with sign offs that I can
> grab easily.

I'm waiting for review on v3 of the SH Mobile DRM driver and was planning to 
then send a pull request that will include the GEM and KMS CAM helpers.

-- 
Regards,

Laurent Pinchart