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, 3 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/gk20a_scale.c b/drivers/gpu/nvgpu/gk20a/gk20a_scale.c
index 8a92828f..d09a18f8 100644
--- a/drivers/gpu/nvgpu/gk20a/gk20a_scale.c
+++ b/drivers/gpu/nvgpu/gk20a/gk20a_scale.c
@@ -192,6 +192,9 @@ static void gk20a_scale_notify(struct platform_device *pdev, bool busy)
         struct gk20a_scale_profile *profile = g->scale_profile;
         struct devfreq *devfreq = g->devfreq;
 
+        /* update the software shadow */
+        gk20a_pmu_load_update(g);
+
         /* inform edp about new constraint */
         if (platform->prescale)
                 platform->prescale(pdev);