drm/i915: Use intel_PLL_is_valid() in vlv_find_best_dpll()

Everyone else uses intel_PLL_is_valid(), so make VLV use it as well.

We don't have any special p and m limits on VLV, so skip those tests,
and we also need to skip the m1<=m2 test line PNV.

Reorganize the function a bit to move the n check alongside the rest of
the test for the non-derived dividers, and check the derived values
afterwards.

Note that this changes vlv_find_best_dpll() in two ways:
- The .vco comparison is now >max instead of >=max, and since we round
  down when calculating that stuff, we may now allow frequencies slightly
  above the max as we do on other platforms. The previous method
  disallowed exactly max and anything above it.
- We now check the .dot frequency against the data rate limits, which we
  didn't do before.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_display.c

@@ -310,7 +310,13 @@ static const intel_limit_t intel_limits_ironlake_dual_lvds_100m = {
 };
 
 static const intel_limit_t intel_limits_vlv = {
-	.dot = { .min = 25000, .max = 270000 },
+	 /*
+	  * These are the data rate limits (measured in fast clocks)
+	  * since those are the strictest limits we have. The fast
+	  * clock and actual rate limits are more relaxed, so checking
+	  * them would make no difference.
+	  */
+	.dot = { .min = 25000 * 5, .max = 270000 * 5 },
 	.vco = { .min = 4000000, .max = 6000000 },
 	.n = { .min = 1, .max = 7 },
 	.m1 = { .min = 2, .max = 3 },
@@ -451,20 +457,26 @@ static bool intel_PLL_is_valid(struct drm_device *dev,
 			       const intel_limit_t *limit,
 			       const intel_clock_t *clock)
 {
+	if (clock->n   < limit->n.min   || limit->n.max   < clock->n)
+		INTELPllInvalid("n out of range\n");
 	if (clock->p1  < limit->p1.min  || limit->p1.max  < clock->p1)
 		INTELPllInvalid("p1 out of range\n");
-	if (clock->p   < limit->p.min   || limit->p.max   < clock->p)
-		INTELPllInvalid("p out of range\n");
 	if (clock->m2  < limit->m2.min  || limit->m2.max  < clock->m2)
 		INTELPllInvalid("m2 out of range\n");
 	if (clock->m1  < limit->m1.min  || limit->m1.max  < clock->m1)
 		INTELPllInvalid("m1 out of range\n");
-	if (clock->m1 <= clock->m2 && !IS_PINEVIEW(dev))
-		INTELPllInvalid("m1 <= m2\n");
-	if (clock->m   < limit->m.min   || limit->m.max   < clock->m)
-		INTELPllInvalid("m out of range\n");
-	if (clock->n   < limit->n.min   || limit->n.max   < clock->n)
-		INTELPllInvalid("n out of range\n");
+
+	if (!IS_PINEVIEW(dev) && !IS_VALLEYVIEW(dev))
+		if (clock->m1 <= clock->m2)
+			INTELPllInvalid("m1 <= m2\n");
+
+	if (!IS_VALLEYVIEW(dev)) {
+		if (clock->p < limit->p.min || limit->p.max < clock->p)
+			INTELPllInvalid("p out of range\n");
+		if (clock->m < limit->m.min || limit->m.max < clock->m)
+			INTELPllInvalid("m out of range\n");
+	}
+
 	if (clock->vco < limit->vco.min || limit->vco.max < clock->vco)
 		INTELPllInvalid("vco out of range\n");
 	/* XXX: We may need to be checking "Dot clock" depending on the multiplier,
@@ -658,6 +670,7 @@ vlv_find_best_dpll(const intel_limit_t *limit, struct drm_crtc *crtc,
 		   int target, int refclk, intel_clock_t *match_clock,
 		   intel_clock_t *best_clock)
 {
+	struct drm_device *dev = crtc->dev;
 	intel_clock_t clock;
 	unsigned int bestppm = 1000000;
 	/* min update 19.2 MHz */
@@ -683,8 +696,8 @@ vlv_find_best_dpll(const intel_limit_t *limit, struct drm_crtc *crtc,
 
 					vlv_clock(refclk, &clock);
 
-					if (clock.vco < limit->vco.min ||
-					    clock.vco >= limit->vco.max)
+					if (!intel_PLL_is_valid(dev, limit,
+								&clock))
 						continue;
 
 					diff = abs(clock.dot - target);