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, 2 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/gk20a.c b/drivers/gpu/nvgpu/gk20a/gk20a.c
index c0889571..fb8b8b14 100644
--- a/drivers/gpu/nvgpu/gk20a/gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/gk20a.c
@@ -667,6 +667,7 @@ static int gk20a_init_support(struct platform_device *dev)
 
         mutex_init(&g->dbg_sessions_lock);
         mutex_init(&g->client_lock);
+        mutex_init(&g->ch_wdt_lock);
 
         g->remove_support = gk20a_remove_support;
         return 0;
@@ -1449,6 +1450,7 @@ static int gk20a_probe(struct platform_device *dev)
                         CONFIG_GK20A_DEFAULT_TIMEOUT;
         if (tegra_platform_is_silicon())
                 gk20a->timeouts_enabled = true;
+        gk20a->ch_wdt_enabled = true;
 
         /* Set up initial power settings. For non-slicon platforms, disable *
          * power features and for silicon platforms, read from platform data */