gpu: nvgpu: implement per-channel watchdog

Implement per-channel watchdog/timer as per below rules :
- start the timer while submitting first job on channel or if
  no timer is already running
- cancel the timer when job completes
- re-start the timer if there is any incomplete job left
  in the channel's queue
- trigger appropriate recovery method as part of timeout
  handling mechanism

Handle the timeout as per below :
- get timed out channel, and job data
- disable activity on all engines
- check if fence is really pending
- get information on failing engine
- if no engine is failing, just abort the channel
- if engine is failing, trigger the recovery

Also, add flag "ch_wdt_enabled" to enable/disable channel
watchdog mechanism. Watchdog can also be disabled using
global flag "timeouts_enabled"

Set the watchdog time to be 5s using macro
NVGPU_CHANNEL_WATCHDOG_DEFAULT_TIMEOUT_MS

Bug 200133289

Change-Id: I401cf14dd34a210bc429f31bd5216a361edf1237
Signed-off-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-on: http://git-master/r/797072
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Tested-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/gk20a.h b/drivers/gpu/nvgpu/gk20a/gk20a.h
index dd7a7ad4..46940744 100644
--- a/drivers/gpu/nvgpu/gk20a/gk20a.h
+++ b/drivers/gpu/nvgpu/gk20a/gk20a.h
@@ -475,6 +475,9 @@ struct gk20a {
         u32 gr_idle_timeout_default;
         u32 timeouts_enabled;
 
+        u32 ch_wdt_enabled;
+        struct mutex ch_wdt_lock;
+
         bool slcg_enabled;
         bool blcg_enabled;
         bool elcg_enabled;