drm/i915: Move HSW/BDW pll selection logic to intel_dpll_mgr.c

Move the code for selecting and configuring HSW/BDW DDI PLLs into the
shared dpll infrastructure. With this most of the PLL selection logic
for those platforms is in one place. DisplayPort is handled separately,
but that should be fixed on a follow up patch. It also allows a small
clean up of the SPLL logic.

v2: Rebase.

Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1457451987-17466-10-git-send-email-ander.conselvan.de.oliveira@intel.com

1 files changed, 283 insertions, 12 deletions

diff --git a/drivers/gpu/drm/i915/intel_dpll_mgr.c b/drivers/gpu/drm/i915/intel_dpll_mgr.c
index b711407014d2..224c8965ec95 100644
--- a/drivers/gpu/drm/i915/intel_dpll_mgr.c
+++ b/drivers/gpu/drm/i915/intel_dpll_mgr.c
@@ -335,7 +335,8 @@ static void ibx_pch_dpll_disable(struct drm_i915_private *dev_priv,
 }
 
 static struct intel_shared_dpll *
-ibx_get_dpll(struct intel_crtc *crtc, struct intel_crtc_state *crtc_state)
+ibx_get_dpll(struct intel_crtc *crtc, struct intel_crtc_state *crtc_state,
+	     struct intel_encoder *encoder)
 {
 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
 	struct intel_shared_dpll *pll;
@@ -437,15 +438,282 @@ static bool hsw_ddi_spll_get_hw_state(struct drm_i915_private *dev_priv,
 	return val & SPLL_PLL_ENABLE;
 }
 
+static uint32_t hsw_pll_to_ddi_pll_sel(struct intel_shared_dpll *pll)
+{
+	switch (pll->id) {
+	case DPLL_ID_WRPLL1:
+		return PORT_CLK_SEL_WRPLL1;
+	case DPLL_ID_WRPLL2:
+		return PORT_CLK_SEL_WRPLL2;
+	case DPLL_ID_SPLL:
+		return PORT_CLK_SEL_SPLL;
+	default:
+		return PORT_CLK_SEL_NONE;
+	}
+}
+
+#define LC_FREQ 2700
+#define LC_FREQ_2K U64_C(LC_FREQ * 2000)
+
+#define P_MIN 2
+#define P_MAX 64
+#define P_INC 2
+
+/* Constraints for PLL good behavior */
+#define REF_MIN 48
+#define REF_MAX 400
+#define VCO_MIN 2400
+#define VCO_MAX 4800
+
+struct hsw_wrpll_rnp {
+	unsigned p, n2, r2;
+};
+
+static unsigned hsw_wrpll_get_budget_for_freq(int clock)
+{
+	unsigned budget;
+
+	switch (clock) {
+	case 25175000:
+	case 25200000:
+	case 27000000:
+	case 27027000:
+	case 37762500:
+	case 37800000:
+	case 40500000:
+	case 40541000:
+	case 54000000:
+	case 54054000:
+	case 59341000:
+	case 59400000:
+	case 72000000:
+	case 74176000:
+	case 74250000:
+	case 81000000:
+	case 81081000:
+	case 89012000:
+	case 89100000:
+	case 108000000:
+	case 108108000:
+	case 111264000:
+	case 111375000:
+	case 148352000:
+	case 148500000:
+	case 162000000:
+	case 162162000:
+	case 222525000:
+	case 222750000:
+	case 296703000:
+	case 297000000:
+		budget = 0;
+		break;
+	case 233500000:
+	case 245250000:
+	case 247750000:
+	case 253250000:
+	case 298000000:
+		budget = 1500;
+		break;
+	case 169128000:
+	case 169500000:
+	case 179500000:
+	case 202000000:
+		budget = 2000;
+		break;
+	case 256250000:
+	case 262500000:
+	case 270000000:
+	case 272500000:
+	case 273750000:
+	case 280750000:
+	case 281250000:
+	case 286000000:
+	case 291750000:
+		budget = 4000;
+		break;
+	case 267250000:
+	case 268500000:
+		budget = 5000;
+		break;
+	default:
+		budget = 1000;
+		break;
+	}
+
+	return budget;
+}
+
+static void hsw_wrpll_update_rnp(uint64_t freq2k, unsigned budget,
+				 unsigned r2, unsigned n2, unsigned p,
+				 struct hsw_wrpll_rnp *best)
+{
+	uint64_t a, b, c, d, diff, diff_best;
+
+	/* No best (r,n,p) yet */
+	if (best->p == 0) {
+		best->p = p;
+		best->n2 = n2;
+		best->r2 = r2;
+		return;
+	}
+
+	/*
+	 * Output clock is (LC_FREQ_2K / 2000) * N / (P * R), which compares to
+	 * freq2k.
+	 *
+	 * delta = 1e6 *
+	 *	   abs(freq2k - (LC_FREQ_2K * n2/(p * r2))) /
+	 *	   freq2k;
+	 *
+	 * and we would like delta <= budget.
+	 *
+	 * If the discrepancy is above the PPM-based budget, always prefer to
+	 * improve upon the previous solution.  However, if you're within the
+	 * budget, try to maximize Ref * VCO, that is N / (P * R^2).
+	 */
+	a = freq2k * budget * p * r2;
+	b = freq2k * budget * best->p * best->r2;
+	diff = abs_diff(freq2k * p * r2, LC_FREQ_2K * n2);
+	diff_best = abs_diff(freq2k * best->p * best->r2,
+			     LC_FREQ_2K * best->n2);
+	c = 1000000 * diff;
+	d = 1000000 * diff_best;
+
+	if (a < c && b < d) {
+		/* If both are above the budget, pick the closer */
+		if (best->p * best->r2 * diff < p * r2 * diff_best) {
+			best->p = p;
+			best->n2 = n2;
+			best->r2 = r2;
+		}
+	} else if (a >= c && b < d) {
+		/* If A is below the threshold but B is above it?  Update. */
+		best->p = p;
+		best->n2 = n2;
+		best->r2 = r2;
+	} else if (a >= c && b >= d) {
+		/* Both are below the limit, so pick the higher n2/(r2*r2) */
+		if (n2 * best->r2 * best->r2 > best->n2 * r2 * r2) {
+			best->p = p;
+			best->n2 = n2;
+			best->r2 = r2;
+		}
+	}
+	/* Otherwise a < c && b >= d, do nothing */
+}
+
+static void
+hsw_ddi_calculate_wrpll(int clock /* in Hz */,
+			unsigned *r2_out, unsigned *n2_out, unsigned *p_out)
+{
+	uint64_t freq2k;
+	unsigned p, n2, r2;
+	struct hsw_wrpll_rnp best = { 0, 0, 0 };
+	unsigned budget;
+
+	freq2k = clock / 100;
+
+	budget = hsw_wrpll_get_budget_for_freq(clock);
+
+	/* Special case handling for 540 pixel clock: bypass WR PLL entirely
+	 * and directly pass the LC PLL to it. */
+	if (freq2k == 5400000) {
+		*n2_out = 2;
+		*p_out = 1;
+		*r2_out = 2;
+		return;
+	}
+
+	/*
+	 * Ref = LC_FREQ / R, where Ref is the actual reference input seen by
+	 * the WR PLL.
+	 *
+	 * We want R so that REF_MIN <= Ref <= REF_MAX.
+	 * Injecting R2 = 2 * R gives:
+	 *   REF_MAX * r2 > LC_FREQ * 2 and
+	 *   REF_MIN * r2 < LC_FREQ * 2
+	 *
+	 * Which means the desired boundaries for r2 are:
+	 *  LC_FREQ * 2 / REF_MAX < r2 < LC_FREQ * 2 / REF_MIN
+	 *
+	 */
+	for (r2 = LC_FREQ * 2 / REF_MAX + 1;
+	     r2 <= LC_FREQ * 2 / REF_MIN;
+	     r2++) {
+
+		/*
+		 * VCO = N * Ref, that is: VCO = N * LC_FREQ / R
+		 *
+		 * Once again we want VCO_MIN <= VCO <= VCO_MAX.
+		 * Injecting R2 = 2 * R and N2 = 2 * N, we get:
+		 *   VCO_MAX * r2 > n2 * LC_FREQ and
+		 *   VCO_MIN * r2 < n2 * LC_FREQ)
+		 *
+		 * Which means the desired boundaries for n2 are:
+		 * VCO_MIN * r2 / LC_FREQ < n2 < VCO_MAX * r2 / LC_FREQ
+		 */
+		for (n2 = VCO_MIN * r2 / LC_FREQ + 1;
+		     n2 <= VCO_MAX * r2 / LC_FREQ;
+		     n2++) {
+
+			for (p = P_MIN; p <= P_MAX; p += P_INC)
+				hsw_wrpll_update_rnp(freq2k, budget,
+						     r2, n2, p, &best);
+		}
+	}
+
+	*n2_out = best.n2;
+	*p_out = best.p;
+	*r2_out = best.r2;
+}
+
 static struct intel_shared_dpll *
-hsw_get_dpll(struct intel_crtc *crtc, struct intel_crtc_state *crtc_state)
+hsw_get_dpll(struct intel_crtc *crtc, struct intel_crtc_state *crtc_state,
+	     struct intel_encoder *encoder)
 {
 	struct intel_shared_dpll *pll;
+	int clock = crtc_state->port_clock;
 
-	pll = intel_find_shared_dpll(crtc, crtc_state,
-				     DPLL_ID_WRPLL1, DPLL_ID_WRPLL2);
-	if (pll)
-		intel_reference_shared_dpll(pll, crtc_state);
+	if (encoder->type == INTEL_OUTPUT_HDMI) {
+		uint32_t val;
+		unsigned p, n2, r2;
+
+		hsw_ddi_calculate_wrpll(clock * 1000, &r2, &n2, &p);
+
+		val = WRPLL_PLL_ENABLE | WRPLL_PLL_LCPLL |
+		      WRPLL_DIVIDER_REFERENCE(r2) | WRPLL_DIVIDER_FEEDBACK(n2) |
+		      WRPLL_DIVIDER_POST(p);
+
+		memset(&crtc_state->dpll_hw_state, 0,
+		       sizeof(crtc_state->dpll_hw_state));
+
+		crtc_state->dpll_hw_state.wrpll = val;
+
+		pll = intel_find_shared_dpll(crtc, crtc_state,
+					     DPLL_ID_WRPLL1, DPLL_ID_WRPLL2);
+
+	} else if (encoder->type == INTEL_OUTPUT_ANALOG) {
+		if (WARN_ON(crtc_state->port_clock / 2 != 135000))
+			return NULL;
+
+		memset(&crtc_state->dpll_hw_state, 0,
+		       sizeof(crtc_state->dpll_hw_state));
+
+		crtc_state->dpll_hw_state.spll =
+			SPLL_PLL_ENABLE | SPLL_PLL_FREQ_1350MHz | SPLL_PLL_SSC;
+
+		pll = intel_find_shared_dpll(crtc, crtc_state,
+					     DPLL_ID_SPLL, DPLL_ID_SPLL);
+	} else {
+		return NULL;
+	}
+
+	if (!pll)
+		return NULL;
+
+	crtc_state->ddi_pll_sel = hsw_pll_to_ddi_pll_sel(pll);
+
+	intel_reference_shared_dpll(pll, crtc_state);
 
 	return pll;
 }
@@ -570,7 +838,8 @@ out:
 }
 
 static struct intel_shared_dpll *
-skl_get_dpll(struct intel_crtc *crtc, struct intel_crtc_state *crtc_state)
+skl_get_dpll(struct intel_crtc *crtc, struct intel_crtc_state *crtc_state,
+	     struct intel_encoder *encoder)
 {
 	struct intel_shared_dpll *pll;
 
@@ -771,10 +1040,10 @@ out:
 }
 
 static struct intel_shared_dpll *
-bxt_get_dpll(struct intel_crtc *crtc, struct intel_crtc_state *crtc_state)
+bxt_get_dpll(struct intel_crtc *crtc, struct intel_crtc_state *crtc_state,
+	     struct intel_encoder *encoder)
 {
 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
-	struct intel_encoder *encoder;
 	struct intel_digital_port *intel_dig_port;
 	struct intel_shared_dpll *pll;
 	enum intel_dpll_id i;
@@ -844,7 +1113,8 @@ struct intel_dpll_mgr {
 	const struct dpll_info *dpll_info;
 
 	struct intel_shared_dpll *(*get_dpll)(struct intel_crtc *crtc,
-					      struct intel_crtc_state *crtc_state);
+					      struct intel_crtc_state *crtc_state,
+					      struct intel_encoder *encoder);
 };
 
 static const struct dpll_info pch_plls[] = {
@@ -937,7 +1207,8 @@ void intel_shared_dpll_init(struct drm_device *dev)
 
 struct intel_shared_dpll *
 intel_get_shared_dpll(struct intel_crtc *crtc,
-		      struct intel_crtc_state *crtc_state)
+		      struct intel_crtc_state *crtc_state,
+		      struct intel_encoder *encoder)
 {
 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
 	const struct intel_dpll_mgr *dpll_mgr = dev_priv->dpll_mgr;
@@ -945,5 +1216,5 @@ intel_get_shared_dpll(struct intel_crtc *crtc,
 	if (WARN_ON(!dpll_mgr))
 		return NULL;
 
-	return dpll_mgr->get_dpll(crtc, crtc_state);
+	return dpll_mgr->get_dpll(crtc, crtc_state, encoder);
 }