gpu: nvgpu: add target refcount for gk20a_wait_for_idle()

API gk20a_wait_for_idle() right now always waits for
0 usage count

But in case railgating is disabled through sysfs,
usage count will never get to 0
Hence in this case we should wait for usage count
of 1

If platform->user_railgate_disabled is set,
keep target usage count of 1, otherwise keep
target usage count as 0

Bug 200260926

Change-Id: I1a80621ca61babbd6566989dc09a7b20670c649c
Signed-off-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-on: http://git-master/r/1291421
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/gk20a.c b/drivers/gpu/nvgpu/gk20a/gk20a.c
index 44786e4b..16acc1c9 100644
--- a/drivers/gpu/nvgpu/gk20a/gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/gk20a.c
@@ -1776,12 +1776,19 @@ void gk20a_driver_start_unload(struct gk20a *g)
 int gk20a_wait_for_idle(struct device *dev)
 {
         struct gk20a *g = get_gk20a(dev);
+        struct gk20a_platform *platform;
         int wait_length = 150; /* 3 second overall max wait. */
+        int target_usage_count = 0;
 
         if (!g)
                 return -ENODEV;
 
-        while (atomic_read(&g->usage_count) && wait_length-- >= 0)
+        platform = dev_get_drvdata(dev);
+        if (platform->user_railgate_disabled)
+                target_usage_count = 1;
+
+        while ((atomic_read(&g->usage_count) != target_usage_count)
+                        && (wait_length-- >= 0))
                 msleep(20);
 
         if (wait_length < 0) {