gpu: nvgpu: allocate from coherent pool

Maps memory coherently on devices that are connected to a coherent bus.

(1) Add code to be able to get the platform device node.
(2) Create a new flag to mark if the device is connected to a coherent bus
(3) Map memory coherently on coherent devices.

bug 2040331

Change-Id: Ide83a9261acdbbc6e9fef4fc5f38d6f9d0e5ab5b
Signed-off-by: David Nieto <dmartineznie@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1633985
Reviewed-by: svc-mobile-coverity <svc-mobile-coverity@nvidia.com>
Reviewed-by: Alex Waterman <alexw@nvidia.com>
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/gpu/nvgpu/common/linux/nvgpu_mem.c b/drivers/gpu/nvgpu/common/linux/nvgpu_mem.c
index 79098eca..e4b4be06 100644
--- a/drivers/gpu/nvgpu/common/linux/nvgpu_mem.c
+++ b/drivers/gpu/nvgpu/common/linux/nvgpu_mem.c
@@ -61,6 +61,8 @@ u32 nvgpu_aperture_mask(struct gk20a *g, struct nvgpu_mem *mem,
 int nvgpu_mem_begin(struct gk20a *g, struct nvgpu_mem *mem)
 {
         void *cpu_va;
+        pgprot_t prot = nvgpu_is_enabled(g, NVGPU_DMA_COHERENT) ? PAGE_KERNEL :
+                pgprot_writecombine(PAGE_KERNEL);
 
         if (mem->aperture != APERTURE_SYSMEM || g->mm.force_pramin)
                 return 0;
@@ -80,7 +82,7 @@ int nvgpu_mem_begin(struct gk20a *g, struct nvgpu_mem *mem)
 
         cpu_va = vmap(mem->priv.pages,
                         PAGE_ALIGN(mem->size) >> PAGE_SHIFT,
-                        0, pgprot_writecombine(PAGE_KERNEL));
+                        0, prot);
 
         if (WARN_ON(!cpu_va))
                 return -ENOMEM;