gpu: nvgpu: Conditional address space unification

Allow platforms to choose whether or not to have unified GPU
VA spaces. This is useful for the dGPU where having a unified
address space has no problems. On iGPUs testing issues is
getting in the way of enabling this feature.

Bug 1396644
Bug 1729947

Change-Id: I65985f1f9a818f4b06219715cc09619911e4824b
Signed-off-by: Alex Waterman <alexw@nvidia.com>
Reviewed-on: http://git-master/r/1265303
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 15 insertions, 30 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/mm_gk20a.h b/drivers/gpu/nvgpu/gk20a/mm_gk20a.h
index f362e27c..665aea42 100644
--- a/drivers/gpu/nvgpu/gk20a/mm_gk20a.h
+++ b/drivers/gpu/nvgpu/gk20a/mm_gk20a.h
@@ -270,9 +270,16 @@ struct vm_gk20a {
 
         struct gk20a_mm_entry pdb;
 
+        /*
+         * These structs define the address spaces. In some cases it's possible
+         * to merge address spaces (user and user_lp) and in other cases it's
+         * not. vma[] allows the code to be agnostic to this by always using
+         * address spaces through this pointer array.
+         */
         struct nvgpu_allocator *vma[gmmu_nr_page_sizes];
         struct nvgpu_allocator kernel;
         struct nvgpu_allocator user;
+        struct nvgpu_allocator user_lp;
 
         struct rb_root mapped_buffers;
 
@@ -433,41 +440,19 @@ static inline int bar1_aperture_size_mb_gk20a(void)
 /* The default kernel-reserved GPU VA size */
 #define NV_MM_DEFAULT_KERNEL_SIZE (1ULL << 32)
 
-enum gmmu_pgsz_gk20a __get_pte_size_fixed_map(struct vm_gk20a *vm,
-                                              u64 base, u64 size);
-
 /*
- * This determines the PTE size for a given alloc. Used by both the GVA space
- * allocator and the mm core code so that agreement can be reached on how to
- * map allocations.
- *
- * The page size of a buffer is this:
- *
- *   o  If the VM doesn't support large pages then obviously small pages
- *      must be used.
- *   o  If the base address is non-zero (fixed address map):
- *      - Attempt to find a reserved memory area and use the page size
- *        based on that.
- *      - If no reserved page size is available, default to small pages.
- *   o  If the base is zero:
- *      - If the size is greater than or equal to the big page size, use big
- *        pages.
- *      - Otherwise use small pages.
+ * When not using unified address spaces the bottom 16GB of the space are used
+ * for small pages and the remaining high memory is used for large pages.
  */
-static inline enum gmmu_pgsz_gk20a __get_pte_size(struct vm_gk20a *vm,
-                                                  u64 base, u64 size)
+static inline u64 __nv_gmmu_va_small_page_limit(void)
 {
-        if (!vm->big_pages)
-                return gmmu_page_size_small;
-
-        if (base)
-                return __get_pte_size_fixed_map(vm, base, size);
-
-        if (size >= vm->gmmu_page_sizes[gmmu_page_size_big])
-                return gmmu_page_size_big;
-        return gmmu_page_size_small;
+        return ((u64)SZ_1G * 16);
 }
 
+enum gmmu_pgsz_gk20a __get_pte_size_fixed_map(struct vm_gk20a *vm,
+                                              u64 base, u64 size);
+enum gmmu_pgsz_gk20a __get_pte_size(struct vm_gk20a *vm, u64 base, u64 size);
+
 /*
  * Buffer accessors - wrap between begin() and end() if there is no permanent
  * kernel mapping for this buffer.