gpu: nvgpu: protect recovery with engines_reset_mutex

Rename gr_reset_mutex to engines_reset_mutex and acquire it
before initiating recovery. Recovery running in parallel with
engine reset is not recommended.

On hitting engine reset, h/w drops the ctxsw_status to INVALID in
fifo_engine_status register. Also while the engine is held in reset
h/w passes busy/idle straight through. fifo_engine_status registers
are correct in that there is no context switch outstanding
as the CTXSW is aborted when reset is asserted.

Use deferred_reset_mutex to protect deferred_reset_pending variable
If deferred_reset_pending is true then acquire engines_reset_mutex
and call gk20a_fifo_deferred_reset.
gk20a_fifo_deferred_reset would also check the value of
deferred_reset_pending before initiating reset process

Bug 2092051
Bug 2429295
Bug 2484211
Bug 1890287

Change-Id: I47de669a6203e0b2e9a8237ec4e4747339b9837c
Signed-off-by: Seema Khowala <seemaj@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/2022373
Signed-off-by: Debarshi Dutta <ddutta@nvidia.com>
(cherry-picked from cb91bf1e13740023903282d1c2271d9154e940ba
in dev-main)
Reviewed-on: https://git-master.nvidia.com/r/2024901
GVS: Gerrit_Virtual_Submit
Reviewed-by: Bibek Basu <bbasu@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/fifo_gk20a.h b/drivers/gpu/nvgpu/gk20a/fifo_gk20a.h
index 0c9d9101..26365cae 100644
--- a/drivers/gpu/nvgpu/gk20a/fifo_gk20a.h
+++ b/drivers/gpu/nvgpu/gk20a/fifo_gk20a.h
@@ -184,7 +184,7 @@ struct fifo_gk20a {
         /* zero-kref'd channels here */
         struct nvgpu_list_node free_chs;
         struct nvgpu_mutex free_chs_mutex;
-        struct nvgpu_mutex gr_reset_mutex;
+        struct nvgpu_mutex engines_reset_mutex;
 
         struct tsg_gk20a *tsg;
         struct nvgpu_mutex tsg_inuse_mutex;