gpu: nvgpu: Fix address space limit computation

The address space limit was being computed with the assumption
that the va_limit field is inclusive. The va_limit field is
actually not inclusive. It points to the first invalid byte.

Thus when generating the adr_limit register the code incorrectly
calculated that the address limit should be 0. To fix this the
computation now just uses va_limit - 1.

Also, the bitwise OR of 0xfff into the lower limit word was
incorrect. The bottom 12 bits of the lower 32 bit word are
ignored by the GPU and as such should not be populated.

Change-Id: Ifcc13343aaf50776f3cf1a1e3726e73ffde5003f
Signed-off-by: Alex Waterman <alexw@nvidia.com>
Reviewed-on: http://git-master/r/756690
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-on: http://git-master/r/771151
Reviewed-by: Yu-Huan Hsu <yhsu@nvidia.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/mm_gk20a.c b/drivers/gpu/nvgpu/gk20a/mm_gk20a.c
index 0deadfd0..32ccc5b8 100644
--- a/drivers/gpu/nvgpu/gk20a/mm_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/mm_gk20a.c
@@ -3209,10 +3209,10 @@ void gk20a_init_inst_block(struct mem_desc *inst_block, struct vm_gk20a *vm,
         g->ops.mm.init_pdb(g, inst_ptr, pde_addr);
 
         gk20a_mem_wr32(inst_ptr, ram_in_adr_limit_lo_w(),
-                 u64_lo32(vm->va_limit) | 0xFFF);
+                u64_lo32(vm->va_limit - 1) & ~0xfff);
 
         gk20a_mem_wr32(inst_ptr, ram_in_adr_limit_hi_w(),
-                ram_in_adr_limit_hi_f(u64_hi32(vm->va_limit)));
+                ram_in_adr_limit_hi_f(u64_hi32(vm->va_limit - 1)));
 
         if (big_page_size && g->ops.mm.set_big_page_size)
                 g->ops.mm.set_big_page_size(g, inst_ptr, big_page_size);