drm/i915: Store the /5 target clock in struct dpll on vlv/chv

Unify vlv/chv with earlier platforms so that the sturct dpll::dot
represents the /5 clock frequency (ie. DP symbol rate or HDMI
TMDS rate) rather than the *5 fast clock (/2 of the bitrate).
Makes life a little less confusing to get the same number back
in .dot which we fed into the DPLL algorithm.

v2: Actually just include the 5x in the final P divider
    Do the same change to the hand rolled gvt code
v3: Missed a few *5 in *_find_best_dpll()
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220309214301.22899-1-ville.syrjala@linux.intel.com

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

@@ -254,12 +254,12 @@ static const struct intel_limit ilk_limits_dual_lvds_100m = {
 
 static const struct intel_limit intel_limits_vlv = {
 	 /*
-	  * These are the data rate limits (measured in fast clocks)
+	  * These are based on 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 },
+	.dot = { .min = 25000, .max = 270000 },
 	.vco = { .min = 4000000, .max = 6000000 },
 	.n = { .min = 1, .max = 7 },
 	.m1 = { .min = 2, .max = 3 },
@@ -270,12 +270,12 @@ static const struct intel_limit intel_limits_vlv = {
 
 static const struct intel_limit intel_limits_chv = {
 	/*
-	 * These are the data rate limits (measured in fast clocks)
+	 * These are based on 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 = 540000 * 5},
+	.dot = { .min = 25000, .max = 540000 },
 	.vco = { .min = 4800000, .max = 6480000 },
 	.n = { .min = 1, .max = 1 },
 	.m1 = { .min = 2, .max = 2 },
@@ -337,26 +337,26 @@ int i9xx_calc_dpll_params(int refclk, struct dpll *clock)
 int vlv_calc_dpll_params(int refclk, struct dpll *clock)
 {
 	clock->m = clock->m1 * clock->m2;
-	clock->p = clock->p1 * clock->p2;
+	clock->p = clock->p1 * clock->p2 * 5;
 	if (WARN_ON(clock->n == 0 || clock->p == 0))
 		return 0;
 	clock->vco = DIV_ROUND_CLOSEST(refclk * clock->m, clock->n);
 	clock->dot = DIV_ROUND_CLOSEST(clock->vco, clock->p);
 
-	return clock->dot / 5;
+	return clock->dot;
 }
 
 int chv_calc_dpll_params(int refclk, struct dpll *clock)
 {
 	clock->m = clock->m1 * clock->m2;
-	clock->p = clock->p1 * clock->p2;
+	clock->p = clock->p1 * clock->p2 * 5;
 	if (WARN_ON(clock->n == 0 || clock->p == 0))
 		return 0;
 	clock->vco = DIV_ROUND_CLOSEST_ULL(mul_u32_u32(refclk, clock->m),
 					   clock->n << 22);
 	clock->dot = DIV_ROUND_CLOSEST(clock->vco, clock->p);
 
-	return clock->dot / 5;
+	return clock->dot;
 }
 
 /*
@@ -659,8 +659,6 @@ vlv_find_best_dpll(const struct intel_limit *limit,
 	int max_n = min(limit->n.max, refclk / 19200);
 	bool found = false;
 
-	target *= 5; /* fast clock */
-
 	memset(best_clock, 0, sizeof(*best_clock));
 
 	/* based on hardware requirement, prefer smaller n to precision */
@@ -668,7 +666,7 @@ vlv_find_best_dpll(const struct intel_limit *limit,
 		for (clock.p1 = limit->p1.max; clock.p1 >= limit->p1.min; clock.p1--) {
 			for (clock.p2 = limit->p2.p2_fast; clock.p2 >= limit->p2.p2_slow;
 			     clock.p2 -= clock.p2 > 10 ? 2 : 1) {
-				clock.p = clock.p1 * clock.p2;
+				clock.p = clock.p1 * clock.p2 * 5;
 				/* based on hardware requirement, prefer bigger m1,m2 values */
 				for (clock.m1 = limit->m1.min; clock.m1 <= limit->m1.max; clock.m1++) {
 					unsigned int ppm;
@@ -729,7 +727,6 @@ chv_find_best_dpll(const struct intel_limit *limit,
 	 */
 	clock.n = 1;
 	clock.m1 = 2;
-	target *= 5;	/* fast clock */
 
 	for (clock.p1 = limit->p1.max; clock.p1 >= limit->p1.min; clock.p1--) {
 		for (clock.p2 = limit->p2.p2_fast;
@@ -737,7 +734,7 @@ chv_find_best_dpll(const struct intel_limit *limit,
 				clock.p2 -= clock.p2 > 10 ? 2 : 1) {
 			unsigned int error_ppm;
 
-			clock.p = clock.p1 * clock.p2;
+			clock.p = clock.p1 * clock.p2 * 5;
 
 			m2 = DIV_ROUND_CLOSEST_ULL(mul_u32_u32(target, clock.p * clock.n) << 22,
 						   refclk * clock.m1);

drivers/gpu/drm/i915/gvt/handlers.c

@@ -583,7 +583,7 @@ static u32 bxt_vgpu_get_dp_bitrate(struct intel_vgpu *vgpu, enum port port)
 	clock.p1 = (vgpu_vreg_t(vgpu, BXT_PORT_PLL_EBB_0(phy, ch)) & PORT_PLL_P1_MASK) >> PORT_PLL_P1_SHIFT;
 	clock.p2 = (vgpu_vreg_t(vgpu, BXT_PORT_PLL_EBB_0(phy, ch)) & PORT_PLL_P2_MASK) >> PORT_PLL_P2_SHIFT;
 	clock.m = clock.m1 * clock.m2;
-	clock.p = clock.p1 * clock.p2;
+	clock.p = clock.p1 * clock.p2 * 5;
 
 	if (clock.n == 0 || clock.p == 0) {
 		gvt_dbg_dpy("vgpu-%d PORT_%c PLL has invalid divider\n", vgpu->id, port_name(port));
@@ -593,7 +593,7 @@ static u32 bxt_vgpu_get_dp_bitrate(struct intel_vgpu *vgpu, enum port port)
 	clock.vco = DIV_ROUND_CLOSEST_ULL(mul_u32_u32(refclk, clock.m), clock.n << 22);
 	clock.dot = DIV_ROUND_CLOSEST(clock.vco, clock.p);
 
-	dp_br = clock.dot / 5;
+	dp_br = clock.dot;
 
 out:
 	return dp_br;