gpu: nvgpu: take platform power ref at power on

Currently, host1x power refcount may decrement
to 0, while GPU is still powered on and we're still
servicing IRQs. So to prevent this situation,,
take a ref while GPU is being powered on, and
decrement it during power off. Since we are always
holding one reference while GPU is powered on,
we can remove this handling from gk20a_busy/idle().

Bug 200187507

Change-Id: Idabe88754f009f1e8de8dc821d53be3e013dc657
Signed-off-by: Sachit Kadle <skadle@nvidia.com>
Reviewed-on: http://git-master/r/1172320
(cherry picked from commit 3e27e6a5820f5c1ad05596553d75e8979b71f1bd)
Reviewed-on: http://git-master/r/1172607
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 15 insertions, 18 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/gk20a.c b/drivers/gpu/nvgpu/gk20a/gk20a.c
index 44ed4e51..05599649 100644
--- a/drivers/gpu/nvgpu/gk20a/gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/gk20a.c
@@ -696,6 +696,7 @@ static int gk20a_init_support(struct platform_device *dev)
 static int gk20a_pm_prepare_poweroff(struct device *dev)
 {
         struct gk20a *g = get_gk20a(dev);
+        struct gk20a_platform *platform = gk20a_get_platform(dev);
         int ret = 0;
 
         gk20a_dbg_fn("");
@@ -733,6 +734,10 @@ static int gk20a_pm_prepare_poweroff(struct device *dev)
 
         g->power_on = false;
 
+        /* Decrement platform power refcount */
+        if (platform->idle)
+                platform->idle(dev);
+
         /* Stop CPU from accessing the GPU registers. */
         gk20a_lockout_registers(g);
 
@@ -779,6 +784,16 @@ int gk20a_pm_finalize_poweron(struct device *dev)
 
         trace_gk20a_finalize_poweron(dev_name(dev));
 
+        /* Increment platform power refcount */
+        if (platform->busy) {
+                err = platform->busy(dev);
+                if (err < 0) {
+                        dev_err(dev, "%s: failed to poweron platform dependency\n",
+                                __func__);
+                        return err;
+                }
+        }
+
         err = gk20a_restore_registers(g);
         if (err)
                 return err;
@@ -1802,27 +1817,13 @@ int gk20a_busy(struct device *dev)
 {
         int ret = 0;
         struct gk20a *g = get_gk20a(dev);
-#ifdef CONFIG_PM
-        struct gk20a_platform *platform = gk20a_get_platform(dev);
-#endif
 
         down_read(&g->busy_lock);
 
 #ifdef CONFIG_PM
-        if (platform->busy) {
-                ret = platform->busy(dev);
-                if (ret < 0) {
-                        dev_err(dev, "%s: failed to poweron platform dependency\n",
-                                __func__);
-                        goto fail;
-                }
-        }
-
         ret = pm_runtime_get_sync(dev);
         if (ret < 0) {
                 pm_runtime_put_noidle(dev);
-                if (platform->idle)
-                        platform->idle(dev);
                 goto fail;
         }
 #else
@@ -1845,14 +1846,10 @@ fail:
 void gk20a_idle(struct device *dev)
 {
 #ifdef CONFIG_PM
-        struct gk20a_platform *platform = gk20a_get_platform(dev);
         if (atomic_read(&dev->power.usage_count) == 1)
                 gk20a_scale_notify_idle(dev);
         pm_runtime_mark_last_busy(dev);
         pm_runtime_put_sync_autosuspend(dev);
-
-        if (platform->idle)
-                platform->idle(dev);
 #else
         gk20a_scale_notify_idle(dev);
 #endif