gpu: nvgpu: add vidmem allocation API

Add in-nvgpu APIs for allocating and freeing mem_descs in video memory.
Changes for gmmu tables etc. will be added in upcoming changes.

Video memory is allocated via nvmap by initially registering the
aperture size to it and binding it to a struct device, and then going
via the usual dma alloc. This API allows also fixed-address allocations,
meant for reserving special memory areas at boot.

The aperture registration is skipped completely if vidmem isn't found
for the particular device.

gk20a_gmmu_alloc_attr() still uses sysmem, and the unmap/free paths
select internally the correct path by the mem_desc's aperture.

Video memory allocation is off by default, and can be turned on with
CONFIG_GK20A_VIDMEM.

JIRA DNVGPU-16

Change-Id: I77eae5ea90cbed6f4b5db0da86c5f70ddf2a34f9
Signed-off-by: Konsta Holtta <kholtta@nvidia.com>
Reviewed-on: http://git-master/r/1157216
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/Kconfig b/drivers/gpu/nvgpu/Kconfig
index 156b7889..6f3a1f8f 100644
--- a/drivers/gpu/nvgpu/Kconfig
+++ b/drivers/gpu/nvgpu/Kconfig
@@ -100,4 +100,13 @@ config GK20A_PCI
         help
           Enable support for GPUs on PCIe bus.
 
+config GK20A_VIDMEM
+        bool "Support separate video memory on nvgpu"
+        depends on GK20A
+        default n
+        help
+          Enable support for using and allocating buffers in a distinct video
+          memory aperture (in contrast to general system memory), available on
+          GPUs that have their own banks. PCIe GPUs have this, for example.
+
 trysource "../nvgpu-t19x/drivers/gpu/nvgpu/Kconfig"