gpu: nvgpu: force CAR reset in do_idle() for gm20b

In gk20a_do_idle(), we wait for platform->railgate_delay
to allow GPU to go into rail gate

But sometimes we set platform->railgate_delay = INT_MAX
to disable GPU rail gating but allow it to suspend during
low power state
Due to this, force_idle API fails (it waits for INT_MAX)

To fix this, allow forcing CAR reset instead of rail gating
with flag "force_reset_in_do_idle" defined in gk20a_platform
Set this flag for gm20b until we fix the railgate_delay

Bug 1517584

Change-Id: I031aa56f87d4db3727e2c3a3e5eeaf18503dd449
Signed-off-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-on: http://git-master/r/593704
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Tested-by: Terje Bergstrom <tbergstrom@nvidia.com>

3 files changed, 13 insertions, 1 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/gk20a.c b/drivers/gpu/nvgpu/gk20a/gk20a.c
index 58108d97..ef0f6a8c 100644
--- a/drivers/gpu/nvgpu/gk20a/gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/gk20a.c
@@ -1659,7 +1659,7 @@ int __gk20a_do_idle(struct platform_device *pdev)
          */
         pm_runtime_put_sync(&pdev->dev);
 
-        if (platform->can_railgate) {
+        if (platform->can_railgate && !platform->force_reset_in_do_idle) {
                 /* add sufficient delay to allow GPU to rail gate */
                 msleep(platform->railgate_delay);
 
diff --git a/drivers/gpu/nvgpu/gk20a/platform_gk20a.h b/drivers/gpu/nvgpu/gk20a/platform_gk20a.h
index 5f7285bf..7638cf15 100644
--- a/drivers/gpu/nvgpu/gk20a/platform_gk20a.h
+++ b/drivers/gpu/nvgpu/gk20a/platform_gk20a.h
@@ -76,6 +76,12 @@ struct gk20a_platform {
         /* Adaptative ELPG: true = enable flase = disable */
         bool enable_aelpg;
 
+        /*
+         * gk20a_do_idle() API can take GPU either into rail gate or CAR reset
+         * This flag can be used to force CAR reset case instead of rail gate
+         */
+        bool force_reset_in_do_idle;
+
         /* Default big page size 64K or 128K */
         u32 default_big_page_size;
 
diff --git a/drivers/gpu/nvgpu/gk20a/platform_gk20a_tegra.c b/drivers/gpu/nvgpu/gk20a/platform_gk20a_tegra.c
index b75420e6..30f7e79a 100644
--- a/drivers/gpu/nvgpu/gk20a/platform_gk20a_tegra.c
+++ b/drivers/gpu/nvgpu/gk20a/platform_gk20a_tegra.c
@@ -485,6 +485,8 @@ static struct gk20a_platform t132_gk20a_tegra_platform = {
         .enable_elpg            = true,
         .enable_aelpg           = true,
 
+        .force_reset_in_do_idle = false,
+
         .default_big_page_size  = SZ_128K,
 
         .probe = gk20a_tegra_probe,
@@ -526,6 +528,8 @@ struct gk20a_platform gk20a_tegra_platform = {
         .enable_elpg            = true,
         .enable_aelpg           = true,
 
+        .force_reset_in_do_idle = false,
+
         .default_big_page_size  = SZ_128K,
 
         .probe = gk20a_tegra_probe,
@@ -568,6 +572,8 @@ struct gk20a_platform gm20b_tegra_platform = {
         .enable_elpg            = true,
         .enable_aelpg           = true,
 
+        .force_reset_in_do_idle = true,
+
         .default_big_page_size  = SZ_128K,
 
         .probe = gk20a_tegra_probe,