[PATCH 10/12] drm/i915: HSW cdclk support

[Mika Kahola <mika.kahola@intel.com>]

From: Ville Syrjälä <ville.syrjala@linux.intel.com>

Implement support for changing the cdclk frequency during runtime on
HSW. VLV/CHV already have support for this, so we can follow their
example for the most part. Only the actual hardware programming differs,
the rest is pretty much the same.

The pipe pixel rate stuff is handled a bit differently for now due to
the difference in pch vs. gmch pfit handling. Eventually we should unify
that part to eliminate what is essentially duplicated code.

v2: Grab rps.hw_lock around sandybridge_pcode_write()
v3: Rebase due to power well vs. .global_resources() reordering

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

v3: Rebased to the latest

Signed-off-by: Mika Kahola <mika.kahola@intel.com>

Author:    Ville Syrjälä <ville.syrjala@linux.intel.com>
---
 drivers/gpu/drm/i915/i915_reg.h      |   3 +
 drivers/gpu/drm/i915/intel_display.c | 140 ++++++++++++++++++++++++++++++++++-
 2 files changed, 140 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index d4cf3bc..74ff995 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -6410,6 +6410,7 @@ enum skl_disp_power_wells {
 #define   GEN6_PCODE_WRITE_D_COMP		0x11
 #define   GEN6_ENCODE_RC6_VID(mv)		(((mv) - 245) / 5)
 #define   GEN6_DECODE_RC6_VID(vids)		(((vids) * 5) + 245)
+#define   HSW_PCODE_DE_WRITE_FREQ_REQ		0x17
 #define   DISPLAY_IPS_CONTROL			0x19
 #define	  HSW_PCODE_DYNAMIC_DUTY_CYCLE_CONTROL	0x1A
 #define GEN6_PCODE_DATA				0x138128
@@ -6859,10 +6860,12 @@ enum skl_disp_power_wells {
 #define  LCPLL_PLL_LOCK			(1<<30)
 #define  LCPLL_CLK_FREQ_MASK		(3<<26)
 #define  LCPLL_CLK_FREQ_450		(0<<26)
+#define  LCPLL_CLK_FREQ_ALT_HSW		(1<<26) /* 337.5 (ULX) or 540 */
 #define  LCPLL_CLK_FREQ_54O_BDW		(1<<26)
 #define  LCPLL_CLK_FREQ_337_5_BDW	(2<<26)
 #define  LCPLL_CLK_FREQ_675_BDW		(3<<26)
 #define  LCPLL_CD_CLOCK_DISABLE		(1<<25)
+#define  LCPLL_ROOT_CD_CLOCK_DISABLE	(1<<24)
 #define  LCPLL_CD2X_CLOCK_DISABLE	(1<<23)
 #define  LCPLL_POWER_DOWN_ALLOW		(1<<22)
 #define  LCPLL_CD_SOURCE_FCLK		(1<<21)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index fa7baf2..35489cd 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5214,7 +5214,16 @@ static void intel_update_max_cdclk(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
-	if (IS_VALLEYVIEW(dev)) {
+	if (IS_HASWELL(dev)) {
+		if (I915_READ(FUSE_STRAP) & HSW_CDCLK_LIMIT)
+			dev_priv->max_cdclk_freq = 450000;
+		else if (IS_HSW_ULX(dev))
+			dev_priv->max_cdclk_freq = 337500;
+		else if (IS_HSW_ULT(dev))
+			dev_priv->max_cdclk_freq = 450000;
+		else
+			dev_priv->max_cdclk_freq = 540000;
+	} else if (IS_VALLEYVIEW(dev)) {
 		dev_priv->max_cdclk_freq = 400000;
 	} else {
 		/* otherwise assume cdclk is fixed */
@@ -9065,6 +9074,125 @@ void hsw_disable_pc8(struct drm_i915_private *dev_priv)
 	intel_prepare_ddi(dev);
 }
 
+/* compute the max rate for new configuration */
+static int ilk_max_pixel_rate(struct drm_i915_private *dev_priv)
+{
+	struct drm_device *dev = dev_priv->dev;
+	struct intel_crtc *crtc;
+	int max_pixel_rate = 0;
+
+	for_each_intel_crtc(dev, crtc) {
+		if (crtc->new_enabled)
+			max_pixel_rate = max((int)max_pixel_rate,
+					     (int)ilk_pipe_pixel_rate(crtc->config));
+	}
+
+	return max_pixel_rate;
+}
+
+static int haswell_calc_cdclk(struct drm_i915_private *dev_priv,
+			      int max_pixel_rate)
+{
+	int cdclk;
+
+	/*
+	 * FIXME should also account for plane ratio
+	 * once 64bpp pixel formats are supported.
+	 */
+	if (max_pixel_rate > 450000)
+		cdclk = 540000;
+	else if (max_pixel_rate > 337500 || !IS_HSW_ULX(dev_priv))
+		cdclk = 450000;
+	else
+		cdclk = 337500;
+
+	/*
+	 * FIXME move the cdclk caclulation to
+	 * compute_config() so we can fail gracegully.
+	 */
+	if (cdclk > dev_priv->max_cdclk_freq) {
+		DRM_ERROR("requested cdclk (%d kHz) exceeds max (%d kHz)\n",
+			  cdclk, dev_priv->max_cdclk_freq);
+		cdclk = dev_priv->max_cdclk_freq;
+	}
+
+	return cdclk;
+}
+
+static void haswell_set_cdclk(struct drm_device *dev, int cdclk)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	uint32_t val;
+
+	if (WARN((I915_READ(LCPLL_CTL) &
+		  (LCPLL_PLL_DISABLE | LCPLL_PLL_LOCK |
+		   LCPLL_CD_CLOCK_DISABLE | LCPLL_ROOT_CD_CLOCK_DISABLE |
+		   LCPLL_CD2X_CLOCK_DISABLE | LCPLL_POWER_DOWN_ALLOW |
+		   LCPLL_CD_SOURCE_FCLK)) != LCPLL_PLL_LOCK,
+		 "trying to change cdclk frequency with cdclk not enabled\n"))
+		return;
+
+	val = I915_READ(LCPLL_CTL);
+	val &= ~LCPLL_CLK_FREQ_MASK;
+
+	switch (cdclk) {
+	case 450000:
+		val |= LCPLL_CLK_FREQ_450;
+		break;
+	case 337500:
+	case 540000:
+		val |= LCPLL_CLK_FREQ_ALT_HSW;
+		break;
+	default:
+		WARN(1, "invalid cdclk frequency\n");
+		return;
+	}
+
+	I915_WRITE(LCPLL_CTL, val);
+
+	if (IS_HSW_ULX(dev)) {
+		mutex_lock(&dev_priv->rps.hw_lock);
+		sandybridge_pcode_write(dev_priv, HSW_PCODE_DE_WRITE_FREQ_REQ,
+					cdclk == 337500);
+		mutex_unlock(&dev_priv->rps.hw_lock);
+	}
+
+	intel_update_cdclk(dev);
+
+	WARN(cdclk != dev_priv->cdclk_freq,
+	     "cdclk requested %d kHz but got %d kHz\n",
+	     cdclk, dev_priv->cdclk_freq);
+}
+
+static void haswell_modeset_global_pipes(struct drm_atomic_state *state,
+					 unsigned *prepare_pipes)
+{
+	struct drm_device *dev = state->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_crtc *crtc;
+	int max_pixel_rate = ilk_max_pixel_rate(dev_priv);
+
+	if (haswell_calc_cdclk(dev_priv, max_pixel_rate) == dev_priv->cdclk_freq)
+		return;
+
+	/* disable/enable all currently active pipes while we change cdclk */
+	for_each_intel_crtc(dev, crtc)
+		if (crtc->base.enabled)
+			*prepare_pipes |= 1 << crtc->pipe;
+}
+
+static void haswell_modeset_global_resources(struct drm_atomic_state *state)
+{
+	struct drm_device *dev = state->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	int max_pixel_rate = ilk_max_pixel_rate(dev_priv);
+	int req_cdclk = haswell_calc_cdclk(dev_priv, max_pixel_rate);
+
+	if (req_cdclk != dev_priv->cdclk_freq) {
+		haswell_set_cdclk(dev, req_cdclk);
+	}
+}
+
 static int haswell_crtc_compute_clock(struct intel_crtc *crtc,
 				      struct intel_crtc_state *crtc_state)
 {
@@ -12221,8 +12349,11 @@ static int __intel_set_mode(struct drm_crtc *crtc,
 	 * mode set on this crtc.  For other crtcs we need to use the
 	 * adjusted_mode bits in the crtc directly.
 	 */
-	if (IS_VALLEYVIEW(dev)) {
-		ret = valleyview_modeset_global_pipes(state, &prepare_pipes);
+	if (IS_VALLEYVIEW(dev) || IS_HASWELL(dev)) {
+		if (IS_VALLEYVIEW(dev))
+			valleyview_modeset_global_pipes(state, &prepare_pipes);
+		else
+			haswell_modeset_global_pipes(state, &prepare_pipes);
 		if (ret)
 			goto done;
 
@@ -14256,6 +14387,9 @@ static void intel_init_display(struct drm_device *dev)
 		dev_priv->display.fdi_link_train = ivb_manual_fdi_link_train;
 	} else if (IS_HASWELL(dev) || IS_BROADWELL(dev)) {
 		dev_priv->display.fdi_link_train = hsw_fdi_link_train;
+		if (IS_HASWELL(dev))
+			dev_priv->display.modeset_global_resources =
+				haswell_modeset_global_resources;
 	} else if (IS_VALLEYVIEW(dev)) {
 		dev_priv->display.modeset_global_resources =
 			valleyview_modeset_global_resources;
-- 
1.9.1

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