gpu: nvgpu: Add sw shadow for load value

Reading the load value may increase CPU power consumption
temprorarily. In most cases we are ok with a value that
was read a moment earlier.

This patch introduces a software shadow for gpu load. The shadow
is updated before starting scaling and all scaling code paths use
the sw shadow.

Change-Id: I53d2ccb8e7f83147f411a14d3104d890dd9af9a3
Signed-off-by: Arto Merilainen <amerilainen@nvidia.com>
Reviewed-on: http://git-master/r/453347
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/pmu_gk20a.h b/drivers/gpu/nvgpu/gk20a/pmu_gk20a.h
index 292aabb0..694e0288 100644
--- a/drivers/gpu/nvgpu/gk20a/pmu_gk20a.h
+++ b/drivers/gpu/nvgpu/gk20a/pmu_gk20a.h
@@ -1079,6 +1079,7 @@ struct pmu_gk20a {
         bool perfmon_ready;
 
         u32 sample_buffer;
+        u32 load_shadow;
 
         struct mutex isr_mutex;
         struct mutex isr_enable_lock;
@@ -1119,6 +1120,7 @@ int pmu_mutex_acquire(struct pmu_gk20a *pmu, u32 id, u32 *token);
 int pmu_mutex_release(struct pmu_gk20a *pmu, u32 id, u32 *token);
 int gk20a_pmu_destroy(struct gk20a *g);
 int gk20a_pmu_load_norm(struct gk20a *g, u32 *load);
+int gk20a_pmu_load_update(struct gk20a *g);
 int gk20a_pmu_debugfs_init(struct platform_device *dev);
 void gk20a_pmu_reset_load_counters(struct gk20a *g);
 void gk20a_pmu_get_load_counters(struct gk20a *g, u32 *busy_cycles,