From 21f6abd901c7cbf3055a566a5aef9d5df5c5329b Mon Sep 17 00:00:00 2001
From: Steven Price <steven.price@arm.com>
Date: Thu, 9 Jan 2020 13:31:04 +0000
Subject: drm/panfrost: Remove core stack power management
Git-commit: a5f768239ebda810cbb622a979301b7fe1c3b9b9
Patch-mainline: v5.7-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322

Explicit management of the GPU's core stacks is only necessary in the
case of a broken integration with the PDC. Since there are no known
platforms which have such a broken integration let's remove the explicit
control from the driver since this apparently causes problems on other
platforms and will have a small performance penality.

The out of tree mali_kbase driver contains this text regarding
controlling the core stack (CONFIGMALI_CORESTACK):

  Enabling this feature on supported GPUs will let the driver powering
  on/off the GPU core stack independently without involving the Power
  Domain Controller. This should only be enabled on platforms which
  integration of the PDC to the Mali GPU is known to be problematic.
  This feature is currently only supported on t-Six and t-HEx GPUs.

  If unsure, say N.

Signed-off-by: Steven Price <steven.price@arm.com>
Acked-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>
Tested-by: Nicolas Boichat <drinkcat@chromium.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200109133104.11661-1-steven.price@arm.com
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/panfrost/panfrost_gpu.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/drivers/gpu/drm/panfrost/panfrost_gpu.c b/drivers/gpu/drm/panfrost/panfrost_gpu.c
index 8822ec13a0d6..460fc190de6e 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gpu.c
+++ b/drivers/gpu/drm/panfrost/panfrost_gpu.c
@@ -309,10 +309,6 @@ void panfrost_gpu_power_on(struct panfrost_device *pfdev)
 	ret = readl_relaxed_poll_timeout(pfdev->iomem + L2_READY_LO,
 		val, val == pfdev->features.l2_present, 100, 1000);
 
-	gpu_write(pfdev, STACK_PWRON_LO, pfdev->features.stack_present);
-	ret |= readl_relaxed_poll_timeout(pfdev->iomem + STACK_READY_LO,
-		val, val == pfdev->features.stack_present, 100, 1000);
-
 	gpu_write(pfdev, SHADER_PWRON_LO, pfdev->features.shader_present);
 	ret |= readl_relaxed_poll_timeout(pfdev->iomem + SHADER_READY_LO,
 		val, val == pfdev->features.shader_present, 100, 1000);
@@ -329,7 +325,6 @@ void panfrost_gpu_power_off(struct panfrost_device *pfdev)
 {
 	gpu_write(pfdev, TILER_PWROFF_LO, 0);
 	gpu_write(pfdev, SHADER_PWROFF_LO, 0);
-	gpu_write(pfdev, STACK_PWROFF_LO, 0);
 	gpu_write(pfdev, L2_PWROFF_LO, 0);
 }
 
-- 
2.28.0