gpu: nvgpu: fix reset clock in gm20b

To assert reset on GPU, we store "gpu_ref" clock in
platform->clk[0] and use it to assert/deassert reset

But for gm20b, "gpu_ref" is no longer resettable.

To fix this, add two callbacks in gk20a_platform :
.reset_assert and .reset_deassert
Also, add a pointer "clk_reset" to store the clock
which needs to be reset

For gk20a specific implementation, we continue to
reset platform->clk[0]

For gm20b specific implementation, we first request
"gpu_gate" clock, store it and use it to assert reset

Bug 1513685
Bug 1517584

Change-Id: I15a583a4a07eb663b442084be8b8c7d0c7c7a142
Signed-off-by: Deepak Nibade <dnibade@nvidia.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/platform_gk20a.h b/drivers/gpu/nvgpu/gk20a/platform_gk20a.h
index 0cc04595..5f7285bf 100644
--- a/drivers/gpu/nvgpu/gk20a/platform_gk20a.h
+++ b/drivers/gpu/nvgpu/gk20a/platform_gk20a.h
@@ -155,6 +155,11 @@ struct gk20a_platform {
          */
         void (*dump_platform_dependencies)(struct platform_device *dev);
 
+        /* Callbacks to assert/deassert GPU reset */
+        int (*reset_assert)(struct platform_device *pdev);
+        int (*reset_deassert)(struct platform_device *pdev);
+        struct clk *clk_reset;
+
         bool virtual_dev;
 #ifdef CONFIG_TEGRA_GR_VIRTUALIZATION
         u64 virt_handle;