gpu: nvgpu: add GK20A_PM_QOS Kconfig option

GK20A_DEVFREQ scaling depends on Nvidia downstream kernel
modifications to PM QoS framework. To break that dependency and to
allow devfreq based scaling to work without those changes, introduce a
Kconfig option to conditionally enable the PM Qos based constraints.

Bug 200414723
Bug 200414600

Change-Id: If39a144dfb322176c2d0e6c17d57d0cd6d885c41
Signed-off-by: Timo Alho <talho@nvidia.com>
Signed-off-by: Debarshi Dutta <ddutta@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1762987
Reviewed-by: svc-mobile-coverity <svc-mobile-coverity@nvidia.com>
Reviewed-by: Deepak Nibade <dnibade@nvidia.com>
GVS: Gerrit_Virtual_Submit
Reviewed-by: Vijayakumar Subbu <vsubbu@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

2 files changed, 21 insertions, 3 deletions

diff --git a/drivers/gpu/nvgpu/Kconfig b/drivers/gpu/nvgpu/Kconfig
index 84c30666..0c78f67f 100644
--- a/drivers/gpu/nvgpu/Kconfig
+++ b/drivers/gpu/nvgpu/Kconfig
@@ -32,6 +32,14 @@ config GK20A_DEVFREQ
 
 endchoice
 
+config GK20A_PM_QOS
+        depends on GK20A_DEVFREQ
+        bool "Use PM_QOS constraints for devfreq based scaling"
+        default y
+        help
+          Enable support to pass PM_QOS constraints to devfreq based
+          scaling.
+
 config NVGPU_TRACK_MEM_USAGE
         bool "Track the usage of system memory in nvgpu"
         depends on GK20A
diff --git a/drivers/gpu/nvgpu/os/linux/scale.c b/drivers/gpu/nvgpu/os/linux/scale.c
index 84ac1cfd..72ed94bd 100644
--- a/drivers/gpu/nvgpu/os/linux/scale.c
+++ b/drivers/gpu/nvgpu/os/linux/scale.c
@@ -1,7 +1,7 @@
 /*
  * gk20a clock scaling profile
  *
- * Copyright (c) 2013-2017, NVIDIA Corporation. All rights reserved.
+ * Copyright (c) 2013-2018, NVIDIA Corporation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -38,7 +38,7 @@
  * has changed. The function calls postscaling callback if it is defined.
  */
 
-#if defined(CONFIG_COMMON_CLK)
+#if defined(CONFIG_GK20A_PM_QOS) && defined(CONFIG_COMMON_CLK)
 int gk20a_scale_qos_notify(struct notifier_block *nb,
                           unsigned long n, void *p)
 {
@@ -71,7 +71,7 @@ int gk20a_scale_qos_notify(struct notifier_block *nb,
 
         return NOTIFY_OK;
 }
-#else
+#elif defined(CONFIG_GK20A_PM_QOS)
 int gk20a_scale_qos_notify(struct notifier_block *nb,
                           unsigned long n, void *p)
 {
@@ -100,6 +100,12 @@ int gk20a_scale_qos_notify(struct notifier_block *nb,
 
         return NOTIFY_OK;
 }
+#else
+int gk20a_scale_qos_notify(struct notifier_block *nb,
+                          unsigned long n, void *p)
+{
+        return 0;
+}
 #endif
 
 /*
@@ -368,6 +374,7 @@ void gk20a_scale_init(struct device *dev)
                 l->devfreq = devfreq;
         }
 
+#ifdef CONFIG_GK20A_PM_QOS
         /* Should we register QoS callback for this device? */
         if (platform->qos_notify) {
                 profile->qos_notify_block.notifier_call =
@@ -378,6 +385,7 @@ void gk20a_scale_init(struct device *dev)
                 pm_qos_add_max_notifier(PM_QOS_GPU_FREQ_BOUNDS,
                                         &profile->qos_notify_block);
         }
+#endif
 
         return;
 
@@ -392,12 +400,14 @@ void gk20a_scale_exit(struct device *dev)
         struct nvgpu_os_linux *l = nvgpu_os_linux_from_gk20a(g);
         int err;
 
+#ifdef CONFIG_GK20A_PM_QOS
         if (platform->qos_notify) {
                 pm_qos_remove_min_notifier(PM_QOS_GPU_FREQ_BOUNDS,
                                 &g->scale_profile->qos_notify_block);
                 pm_qos_remove_max_notifier(PM_QOS_GPU_FREQ_BOUNDS,
                                 &g->scale_profile->qos_notify_block);
         }
+#endif
 
         if (platform->devfreq_governor) {
                 err = devfreq_remove_device(l->devfreq);