[Intel-gfx] [PATCH v2 4/8] drm/i915/skl: Assert the requirements to enter or exit DC5.

[Animesh Manna]

From: Suketu Shah <suketu.j.shah at intel.com>

Warn if the conditions to enter or exit DC5 are not satisfied such
as support for runtime PM, state of power well, CSR loading etc.

v2: Removed camelcase in functions and variables.

v3: Do some minimal check to assert if CSR program is not loaded.

v4:
1] Used an appropriate function lookup_power_well() to identify power well,
instead of using a magic number which can change in future.
2] Split the conditions further in assert_can_enable_DC5() and added more checks.
3] Removed all WARNs from assert_can_disable_DC5 as they were unnecessary and added two
   new ones.
4] Changed variable names as updated in earlier patches.

v5:
1] Change lookup_power_well function to take an int power well id.
2] Define a new intel_display_power_well_is_enabled helper function to check whether a
   particular power well is enabled.
3] Use CSR-related mutex in assert_csr_loaded function.

v6: Remove use of dc5_enabled variable as it's no longer needed.

v7:
1] Rebase to latest.
2] Move all DC5-related functions from intel_display.c to intel_runtime_pm.c.

v8: After adding dmc ver 1.0 support rebased on top of nightly. (Animesh)

v9: Modified below chnages based on review comments from Imre.
- Moved intel_display_power_well_is_enabled() to intel_runtime_pm.c.
- Removed mutex lock from assert_csr_loaded(). (Animesh)

Issue: VIZ-2819
Signed-off-by: A.Sunil Kamath <sunil.kamath at intel.com>
Signed-off-by: Suketu Shah <suketu.j.shah at intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau at intel.com>
Signed-off-by: Animesh Manna <animesh.manna at intel.com>
---
 drivers/gpu/drm/i915/intel_runtime_pm.c | 61 ++++++++++++++++++++++++++++++---
 1 file changed, 56 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index 0750191..db25eb7 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -31,6 +31,7 @@
 
 #include "i915_drv.h"
 #include "intel_drv.h"
+#include "intel_csr.h"
 
 /**
  * DOC: runtime pm
@@ -64,6 +65,9 @@
 	     i--)							 \
 		if ((power_well)->domains & (domain_mask))
 
+bool intel_display_power_well_is_enabled(struct drm_i915_private *dev_priv,
+				    int power_well_id);
+
 /*
  * We should only use the power well if we explicitly asked the hardware to
  * enable it, so check if it's enabled and also check if we've requested it to
@@ -335,12 +339,48 @@ static void gen9_set_dc_state_debugmask_memory_up(
 	}
 }
 
-static void gen9_enable_dc5(struct drm_i915_private *dev_priv)
+static void assert_csr_loaded(struct drm_i915_private *dev_priv)
+{
+	WARN(!dev_priv->csr.states, "CSR is not loaded.\n");
+	WARN(!I915_READ(CSR_PROGRAM_BASE),
+				"CSR program storage start is NULL\n");
+	WARN(!I915_READ(CSR_SSP_BASE), "CSR SSP Base Not fine\n");
+	WARN(!I915_READ(CSR_HTP_SKL), "CSR HTP Not fine\n");
+}
+
+static void assert_can_enable_dc5(struct drm_i915_private *dev_priv)
 {
 	struct drm_device *dev = dev_priv->dev;
+	bool pg2_enabled = intel_display_power_well_is_enabled(dev_priv,
+					SKL_DISP_PW_2);
+
+	WARN(!IS_SKYLAKE(dev), "Platform doesn't support DC5.\n");
+	WARN(!HAS_RUNTIME_PM(dev), "Runtime PM not enabled.\n");
+	WARN(pg2_enabled, "PG2 not disabled to enable DC5.\n");
+
+	WARN((I915_READ(DC_STATE_EN) & DC_STATE_EN_UPTO_DC5),
+				"DC5 already programmed to be enabled.\n");
+	WARN(dev_priv->pm.suspended,
+		"DC5 cannot be enabled, if platform is runtime-suspended.\n");
+
+	assert_csr_loaded(dev_priv);
+}
+
+static void assert_can_disable_dc5(struct drm_i915_private *dev_priv)
+{
+	bool pg2_enabled = intel_display_power_well_is_enabled(dev_priv,
+					SKL_DISP_PW_2);
+
+	WARN(!pg2_enabled, "PG2 not enabled to disable DC5.\n");
+	WARN(dev_priv->pm.suspended,
+		"Disabling of DC5 while platform is runtime-suspended should never happen.\n");
+}
+
+static void gen9_enable_dc5(struct drm_i915_private *dev_priv)
+{
 	uint32_t val;
 
-	WARN_ON(!IS_GEN9(dev));
+	assert_can_enable_dc5(dev_priv);
 
 	DRM_DEBUG_KMS("Enabling DC5\n");
 
@@ -355,10 +395,9 @@ static void gen9_enable_dc5(struct drm_i915_private *dev_priv)
 
 static void gen9_disable_dc5(struct drm_i915_private *dev_priv)
 {
-	struct drm_device *dev = dev_priv->dev;
 	uint32_t val;
 
-	WARN_ON(!IS_GEN9(dev));
+	assert_can_disable_dc5(dev_priv);
 
 	DRM_DEBUG_KMS("Disabling DC5\n");
 
@@ -1324,7 +1363,7 @@ static struct i915_power_well chv_power_wells[] = {
 };
 
 static struct i915_power_well *lookup_power_well(struct drm_i915_private *dev_priv,
-						 enum punit_power_well power_well_id)
+						 int power_well_id)
 {
 	struct i915_power_domains *power_domains = &dev_priv->power_domains;
 	struct i915_power_well *power_well;
@@ -1338,6 +1377,18 @@ static struct i915_power_well *lookup_power_well(struct drm_i915_private *dev_pr
 	return NULL;
 }
 
+bool intel_display_power_well_is_enabled(struct drm_i915_private *dev_priv,
+				    int power_well_id)
+{
+	struct i915_power_well *power_well;
+	bool ret;
+
+	power_well = lookup_power_well(dev_priv, power_well_id);
+	ret = power_well->ops->is_enabled(dev_priv, power_well);
+
+	return ret;
+}
+
 static struct i915_power_well skl_power_wells[] = {
 	{
 		.name = "always-on",
-- 
2.0.2