drm/i915: Add i915_lpsp_status debugfs attribute

It requires a separate debugfs attribute to expose lpsp
status to user space, as there may be display less configuration
without any valid connected output, those configuration will not be
able to test lpsp status, if lpsp status exposed from a connector
based debugfs attribute.
Reviewed-by: Animesh Manna <animesh.manna@intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200415170555.15531-5-anshuman.gupta@intel.com

drivers/gpu/drm/i915/display/intel_display_debugfs.c

@@ -9,6 +9,7 @@
 #include "i915_debugfs.h"
 #include "intel_csr.h"
 #include "intel_display_debugfs.h"
+#include "intel_display_power.h"
 #include "intel_display_types.h"
 #include "intel_dp.h"
 #include "intel_fbc.h"
@@ -1149,6 +1150,51 @@ static int i915_drrs_status(struct seq_file *m, void *unused)
 	return 0;
 }
 
+#define LPSP_STATUS(COND) (COND ? seq_puts(m, "LPSP: enabled\n") : \
+				seq_puts(m, "LPSP: disabled\n"))
+
+static bool
+intel_lpsp_power_well_enabled(struct drm_i915_private *i915,
+			      enum i915_power_well_id power_well_id)
+{
+	intel_wakeref_t wakeref;
+	bool is_enabled;
+
+	wakeref = intel_runtime_pm_get(&i915->runtime_pm);
+	is_enabled = intel_display_power_well_is_enabled(i915,
+							 power_well_id);
+	intel_runtime_pm_put(&i915->runtime_pm, wakeref);
+
+	return is_enabled;
+}
+
+static int i915_lpsp_status(struct seq_file *m, void *unused)
+{
+	struct drm_i915_private *i915 = node_to_i915(m->private);
+
+	switch (INTEL_GEN(i915)) {
+	case 12:
+	case 11:
+		LPSP_STATUS(!intel_lpsp_power_well_enabled(i915, ICL_DISP_PW_3));
+		break;
+	case 10:
+	case 9:
+		LPSP_STATUS(!intel_lpsp_power_well_enabled(i915, SKL_DISP_PW_2));
+		break;
+	default:
+		/*
+		 * Apart from HASWELL/BROADWELL other legacy platform doesn't
+		 * support lpsp.
+		 */
+		if (IS_HASWELL(i915) || IS_BROADWELL(i915))
+			LPSP_STATUS(!intel_lpsp_power_well_enabled(i915, HSW_DISP_PW_GLOBAL));
+		else
+			seq_puts(m, "LPSP: not supported\n");
+	}
+
+	return 0;
+}
+
 static int i915_dp_mst_info(struct seq_file *m, void *unused)
 {
 	struct drm_i915_private *dev_priv = node_to_i915(m->private);
@@ -1916,6 +1962,7 @@ static const struct drm_info_list intel_display_debugfs_list[] = {
 	{"i915_dp_mst_info", i915_dp_mst_info, 0},
 	{"i915_ddb_info", i915_ddb_info, 0},
 	{"i915_drrs_status", i915_drrs_status, 0},
+	{"i915_lpsp_status", i915_lpsp_status, 0},
 };
 
 static const struct {

drivers/gpu/drm/i915/display/intel_display_power.h

@@ -266,6 +266,8 @@ intel_display_power_domain_str(enum intel_display_power_domain domain);
 
 bool intel_display_power_is_enabled(struct drm_i915_private *dev_priv,
 				    enum intel_display_power_domain domain);
+bool intel_display_power_well_is_enabled(struct drm_i915_private *dev_priv,
+					 enum i915_power_well_id power_well_id);
 bool __intel_display_power_is_enabled(struct drm_i915_private *dev_priv,
 				      enum intel_display_power_domain domain);
 intel_wakeref_t intel_display_power_get(struct drm_i915_private *dev_priv,