drm/i915: Rename and comment all the RPS *stuff*

The names of the struct members for RPS are stupid. Every time I need to
do anything in this code I have to spend a significant amount of time to
remember what it all means. By renaming the variables (and adding the
comments) I hope to clear up the situation. Indeed doing this make some
upcoming patches more readable.

I've avoided ILK because it's possible that the naming used for Ironlake
matches what is in the docs. I believe the ILK power docs were never
published, and I am too lazy to dig them up.

v2: leave rp0, and rp1 in the names. It is useful to have these limits
available at times. min_freq and max_freq (which may be equal to rp0, or
rp1 depending on the platform) represent the actual HW min and max.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 1c00751..acf1ab3 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -1075,7 +1075,7 @@
 			     u32 pm_iir, int new_delay)
 {
 	if (pm_iir & GEN6_PM_RP_UP_THRESHOLD) {
-		if (new_delay >= dev_priv->rps.max_delay) {
+		if (new_delay >= dev_priv->rps.max_freq_softlimit) {
 			/* Mask UP THRESHOLD Interrupts */
 			I915_WRITE(GEN6_PMINTRMSK,
 				   I915_READ(GEN6_PMINTRMSK) |
@@ -1090,7 +1090,7 @@
 			dev_priv->rps.rp_down_masked = false;
 		}
 	} else if (pm_iir & GEN6_PM_RP_DOWN_THRESHOLD) {
-		if (new_delay <= dev_priv->rps.min_delay) {
+		if (new_delay <= dev_priv->rps.min_freq_softlimit) {
 			/* Mask DOWN THRESHOLD Interrupts */
 			I915_WRITE(GEN6_PMINTRMSK,
 				   I915_READ(GEN6_PMINTRMSK) |
@@ -1136,38 +1136,39 @@
 			adj *= 2;
 		else
 			adj = 1;
-		new_delay = dev_priv->rps.cur_delay + adj;
+		new_delay = dev_priv->rps.cur_freq + adj;
 
 		/*
 		 * For better performance, jump directly
 		 * to RPe if we're below it.
 		 */
-		if (new_delay < dev_priv->rps.rpe_delay)
-			new_delay = dev_priv->rps.rpe_delay;
+		if (new_delay < dev_priv->rps.efficient_freq)
+			new_delay = dev_priv->rps.efficient_freq;
 	} else if (pm_iir & GEN6_PM_RP_DOWN_TIMEOUT) {
-		if (dev_priv->rps.cur_delay > dev_priv->rps.rpe_delay)
-			new_delay = dev_priv->rps.rpe_delay;
+		if (dev_priv->rps.cur_freq > dev_priv->rps.efficient_freq)
+			new_delay = dev_priv->rps.efficient_freq;
 		else
-			new_delay = dev_priv->rps.min_delay;
+			new_delay = dev_priv->rps.min_freq_softlimit;
 		adj = 0;
 	} else if (pm_iir & GEN6_PM_RP_DOWN_THRESHOLD) {
 		if (adj < 0)
 			adj *= 2;
 		else
 			adj = -1;
-		new_delay = dev_priv->rps.cur_delay + adj;
+		new_delay = dev_priv->rps.cur_freq + adj;
 	} else { /* unknown event */
-		new_delay = dev_priv->rps.cur_delay;
+		new_delay = dev_priv->rps.cur_freq;
 	}
 
 	/* sysfs frequency interfaces may have snuck in while servicing the
 	 * interrupt
 	 */
 	new_delay = clamp_t(int, new_delay,
-			    dev_priv->rps.min_delay, dev_priv->rps.max_delay);
+			    dev_priv->rps.min_freq_softlimit,
+			    dev_priv->rps.max_freq_softlimit);
 
 	gen6_set_pm_mask(dev_priv, pm_iir, new_delay);
-	dev_priv->rps.last_adj = new_delay - dev_priv->rps.cur_delay;
+	dev_priv->rps.last_adj = new_delay - dev_priv->rps.cur_freq;
 
 	if (IS_VALLEYVIEW(dev_priv->dev))
 		valleyview_set_rps(dev_priv->dev, new_delay);