gpu: nvgpu: Deal with invalid MMU id

If gk20a_engine_id_to_mmu_id() fails, it returns ~0. Deal with this
by checking the results in each call to it.

Change-Id: I6fb9f7151f21a6c4694bfb2ea3c960d344fe629f
Signed-off-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-on: http://git-master/r/1249965
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 4 insertions, 5 deletions

diff --git a/drivers/gpu/nvgpu/gm20b/fifo_gm20b.c b/drivers/gpu/nvgpu/gm20b/fifo_gm20b.c
index a8934035..3b877db1 100644
--- a/drivers/gpu/nvgpu/gm20b/fifo_gm20b.c
+++ b/drivers/gpu/nvgpu/gm20b/fifo_gm20b.c
@@ -74,16 +74,15 @@ static void gm20b_fifo_trigger_mmu_fault(struct gk20a *g,
 
         /* trigger faults for all bad engines */
         for_each_set_bit(engine_id, &engine_ids, 32) {
-                u32 engine_mmu_fault_id;
-
                 if (!gk20a_fifo_is_valid_engine_id(g, engine_id)) {
                         gk20a_err(dev_from_gk20a(g),
                                   "faulting unknown engine %ld", engine_id);
                 } else {
-                        engine_mmu_fault_id = gm20b_engine_id_to_mmu_id(g,
+                        u32 mmu_id = gm20b_engine_id_to_mmu_id(g,
                                                                 engine_id);
-                        gk20a_writel(g, fifo_trigger_mmu_fault_r(engine_id),
-                                     fifo_trigger_mmu_fault_enable_f(1));
+                        if (mmu_id != ~0)
+                                gk20a_writel(g, fifo_trigger_mmu_fault_r(mmu_id),
+                                             fifo_trigger_mmu_fault_enable_f(1));
                 }
         }