[Intel-gfx] [PATCH v8 2/4] drm/i915/hwmon: Add helper function to obtain energy values

[Riana Tauro]

Add an interface to obtain hwmon energy values. The function returns
per-gt energy if gt level energy is available else returns the package
level energy if there is a single gt.
This is used by selftests to verify power consumption

v2 : use i915_hwmon prefix (Anshuman)
v3 : re-use is_visible function of energy to remove
     redundant code (Anshuman)
v4 : fix kernel-doc (Anshuman)
     add per-gt hwmon support (Ashutosh)
v5 : add check to return package level energy only when there
     is a single gt and gt level energy is not available. (Ashutosh)

Signed-off-by: Riana Tauro <riana.tauro at intel.com>
Reviewed-by: Anshuman Gupta <anshuman.gupta at intel.com>
Reviewed-by: Ashutosh Dixit <ashutosh.dixit at intel.com>
---
 drivers/gpu/drm/i915/i915_hwmon.c | 28 ++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/i915_hwmon.h |  3 +++
 2 files changed, 31 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_hwmon.c b/drivers/gpu/drm/i915/i915_hwmon.c
index 8e7dccc8d3a0..efc2ccaf64d1 100644
--- a/drivers/gpu/drm/i915/i915_hwmon.c
+++ b/drivers/gpu/drm/i915/i915_hwmon.c
@@ -500,6 +500,34 @@ hwm_energy_read(struct hwm_drvdata *ddat, u32 attr, long *val)
 	}
 }
 
+/**
+ * i915_hwmon_get_energy - obtains energy value
+ * @gt: intel_gt structure
+ * @energy: pointer to store energy in uJ
+ *
+ * This function checks for the validity of the underlying energy
+ * hardware register and obtains per-gt level energy
+ * values.
+ *
+ * Return: 0 on success, -EOPNOTSUPP if register is invalid
+ */
+int
+i915_hwmon_get_energy(struct intel_gt *gt, long *energy)
+{
+	struct i915_hwmon *hwmon = gt->i915->hwmon;
+	struct hwm_drvdata *ddat = &hwmon->ddat;
+	struct hwm_drvdata *ddat_gt = hwmon->ddat_gt + gt->info.id;
+
+	if (hwm_energy_is_visible(ddat_gt, hwmon_energy_input))
+		hwm_energy(ddat_gt, energy);
+	else if (!HAS_EXTRA_GT_LIST(gt->i915) && hwm_energy_is_visible(ddat, hwmon_energy_input))
+		hwm_energy(ddat, energy);
+	else
+		return -EOPNOTSUPP;
+
+	return 0;
+}
+
 static umode_t
 hwm_curr_is_visible(const struct hwm_drvdata *ddat, u32 attr)
 {
diff --git a/drivers/gpu/drm/i915/i915_hwmon.h b/drivers/gpu/drm/i915/i915_hwmon.h
index 7ca9cf2c34c9..1c38cfdbb7e9 100644
--- a/drivers/gpu/drm/i915/i915_hwmon.h
+++ b/drivers/gpu/drm/i915/i915_hwmon.h
@@ -8,13 +8,16 @@
 #define __I915_HWMON_H__
 
 struct drm_i915_private;
+struct intel_gt;
 
 #if IS_REACHABLE(CONFIG_HWMON)
 void i915_hwmon_register(struct drm_i915_private *i915);
 void i915_hwmon_unregister(struct drm_i915_private *i915);
+int i915_hwmon_get_energy(struct intel_gt *gt, long *energy);
 #else
 static inline void i915_hwmon_register(struct drm_i915_private *i915) { };
 static inline void i915_hwmon_unregister(struct drm_i915_private *i915) { };
+static inline int i915_hwmon_get_energy(struct intel_gt *gt, long *energy) { return -EOPNOTSUPP; }
 #endif
 
 #endif /* __I915_HWMON_H__ */
-- 
2.40.0