drm/i915: Return residency as microseconds

Change the granularity from milliseconds to microseconds
when returning rc6 residencies. This is in preparation
for increased resolution on some platforms.

v2: use 64bit div macro (Chris)

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/i915_drv.h

@@ -3879,8 +3879,8 @@ void vlv_phy_reset_lanes(struct intel_encoder *encoder);
 
 int intel_gpu_freq(struct drm_i915_private *dev_priv, int val);
 int intel_freq_opcode(struct drm_i915_private *dev_priv, int val);
-u32 intel_rc6_residency(struct drm_i915_private *dev_priv,
-			i915_reg_t reg);
+u64 intel_rc6_residency_us(struct drm_i915_private *dev_priv,
+			   const i915_reg_t reg);
 
 #define I915_READ8(reg)		dev_priv->uncore.funcs.mmio_readb(dev_priv, (reg), true)
 #define I915_WRITE8(reg, val)	dev_priv->uncore.funcs.mmio_writeb(dev_priv, (reg), (val), true)

drivers/gpu/drm/i915/i915_sysfs.c

@@ -42,7 +42,8 @@ static inline struct drm_i915_private *kdev_minor_to_i915(struct device *kdev)
 static u32 calc_residency(struct drm_i915_private *dev_priv,
 			  i915_reg_t reg)
 {
-	return intel_rc6_residency(dev_priv, reg);
+	return DIV_ROUND_CLOSEST_ULL(intel_rc6_residency_us(dev_priv, reg),
+				     1000);
 }
 
 static ssize_t

drivers/gpu/drm/i915/intel_pm.c

@@ -8350,12 +8350,12 @@ void intel_pm_setup(struct drm_i915_private *dev_priv)
 	atomic_set(&dev_priv->pm.wakeref_count, 0);
 }
 
-u32 intel_rc6_residency(struct drm_i915_private *dev_priv,
-			i915_reg_t reg)
+u64 intel_rc6_residency_us(struct drm_i915_private *dev_priv,
+			   const i915_reg_t reg)
 {
 	u64 raw_time; /* 32b value may overflow during fixed point math */
-	u64 units = 128ULL, div = 100000ULL;
-	u32 ret;
+	u64 units = 128000ULL, div = 100000ULL;
+	u64 ret;
 
 	if (!intel_enable_rc6())
 		return 0;
@@ -8364,13 +8364,13 @@ u32 intel_rc6_residency(struct drm_i915_private *dev_priv,
 
 	/* On VLV and CHV, residency time is in CZ units rather than 1.28us */
 	if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv)) {
-		units = 1;
+		units = 1000;
 		div = dev_priv->czclk_freq;
 
 		if (I915_READ(VLV_COUNTER_CONTROL) & VLV_COUNT_RANGE_HIGH)
 			units <<= 8;
 	} else if (IS_GEN9_LP(dev_priv)) {
-		units = 1;
+		units = 1000;
 		div = 1200;		/* 833.33ns */
 	}