drm/i915: Actually read out DPLL0 vco on skl from hardware

Currently we're trying to guess which lcpll vco frequency is used
use based on the cdclk. That doesn't work for cdclk==540 since
both vco frequencies can generate a 540 Mhz output. Let's stop
guessing and just read the actual vco frequency from the
hardware.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463172100-24715-6-git-send-email-ville.syrjala@linux.intel.com
Reviewed-by: Imre Deak <imre.deak@intel.com>

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 78f3918..27b4b88 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5471,31 +5471,35 @@ static int skl_calc_cdclk(int max_pixclk, int vco)
        }
 }
 
-static const struct skl_cdclk_entry {
-       unsigned int freq;
-       unsigned int vco;
-} skl_cdclk_frequencies[] = {
-       { .freq = 308570, .vco = 8640 },
-       { .freq = 337500, .vco = 8100 },
-       { .freq = 432000, .vco = 8640 },
-       { .freq = 450000, .vco = 8100 },
-       { .freq = 540000, .vco = 8100 },
-       { .freq = 617140, .vco = 8640 },
-       { .freq = 675000, .vco = 8100 },
-};
-
-unsigned int skl_cdclk_get_vco(unsigned int freq)
+static void
+skl_dpll0_update(struct drm_i915_private *dev_priv)
 {
-       unsigned int i;
-
-       for (i = 0; i < ARRAY_SIZE(skl_cdclk_frequencies); i++) {
-               const struct skl_cdclk_entry *e = &skl_cdclk_frequencies[i];
+       u32 val;
 
-               if (e->freq == freq)
-                       return e->vco;
+       val = I915_READ(LCPLL1_CTL);
+       if ((val & LCPLL_PLL_ENABLE) == 0) {
+               dev_priv->skl_vco_freq = 0;
+               return;
        }
 
-       return 8100;
+       val = I915_READ(DPLL_CTRL1);
+
+       switch (val & DPLL_CTRL1_LINK_RATE_MASK(SKL_DPLL0)) {
+       case DPLL_CTRL1_LINK_RATE(DPLL_CTRL1_LINK_RATE_810, SKL_DPLL0):
+       case DPLL_CTRL1_LINK_RATE(DPLL_CTRL1_LINK_RATE_1350, SKL_DPLL0):
+       case DPLL_CTRL1_LINK_RATE(DPLL_CTRL1_LINK_RATE_1620, SKL_DPLL0):
+       case DPLL_CTRL1_LINK_RATE(DPLL_CTRL1_LINK_RATE_2700, SKL_DPLL0):
+               dev_priv->skl_vco_freq = 8100;
+               break;
+       case DPLL_CTRL1_LINK_RATE(DPLL_CTRL1_LINK_RATE_1080, SKL_DPLL0):
+       case DPLL_CTRL1_LINK_RATE(DPLL_CTRL1_LINK_RATE_2160, SKL_DPLL0):
+               dev_priv->skl_vco_freq = 8640;
+               break;
+       default:
+               MISSING_CASE(val & DPLL_CTRL1_LINK_RATE_MASK(SKL_DPLL0));
+               dev_priv->skl_vco_freq = 0;
+               break;
+       }
 }
 
 static void
@@ -6540,43 +6544,40 @@ static int intel_crtc_compute_config(struct intel_crtc *crtc,
 static int skylake_get_display_clock_speed(struct drm_device *dev)
 {
        struct drm_i915_private *dev_priv = to_i915(dev);
-       uint32_t lcpll1 = I915_READ(LCPLL1_CTL);
-       uint32_t cdctl = I915_READ(CDCLK_CTL);
-       uint32_t linkrate;
+       uint32_t cdctl;
 
-       if (!(lcpll1 & LCPLL_PLL_ENABLE))
-               return 24000; /* 24MHz is the cd freq with NSSC ref */
+       skl_dpll0_update(dev_priv);
 
-       if ((cdctl & CDCLK_FREQ_SEL_MASK) == CDCLK_FREQ_540)
-               return 540000;
+       if (dev_priv->skl_vco_freq == 0)
+               return 24000; /* 24MHz is the cd freq with NSSC ref */
 
-       linkrate = (I915_READ(DPLL_CTRL1) &
-                   DPLL_CTRL1_LINK_RATE_MASK(SKL_DPLL0)) >> 1;
+       cdctl = I915_READ(CDCLK_CTL);
 
-       if (linkrate == DPLL_CTRL1_LINK_RATE_2160 ||
-           linkrate == DPLL_CTRL1_LINK_RATE_1080) {
-               /* vco 8640 */
+       if (dev_priv->skl_vco_freq == 8640) {
                switch (cdctl & CDCLK_FREQ_SEL_MASK) {
                case CDCLK_FREQ_450_432:
                        return 432000;
                case CDCLK_FREQ_337_308:
                        return 308570;
+               case CDCLK_FREQ_540:
+                       return 540000;
                case CDCLK_FREQ_675_617:
                        return 617140;
                default:
-                       WARN(1, "Unknown cd freq selection\n");
+                       MISSING_CASE(cdctl & CDCLK_FREQ_SEL_MASK);
                }
        } else {
-               /* vco 8100 */
                switch (cdctl & CDCLK_FREQ_SEL_MASK) {
                case CDCLK_FREQ_450_432:
                        return 450000;
                case CDCLK_FREQ_337_308:
                        return 337500;
+               case CDCLK_FREQ_540:
+                       return 540000;
                case CDCLK_FREQ_675_617:
                        return 675000;
                default:
-                       WARN(1, "Unknown cd freq selection\n");
+                       MISSING_CASE(cdctl & CDCLK_FREQ_SEL_MASK);
                }
        }
 

diff --git a/drivers/gpu/drm/i915/intel_dpll_mgr.c b/drivers/gpu/drm/i915/intel_dpll_mgr.c
index 43ba60b..5391ab6 100644 (file)
--- a/drivers/gpu/drm/i915/intel_dpll_mgr.c
+++ b/drivers/gpu/drm/i915/intel_dpll_mgr.c
@@ -1633,14 +1633,8 @@ static void intel_ddi_pll_init(struct drm_device *dev)
        uint32_t val = I915_READ(LCPLL_CTL);
 
        if (IS_SKYLAKE(dev) || IS_KABYLAKE(dev)) {
-               int cdclk_freq;
-
-               cdclk_freq = dev_priv->display.get_display_clock_speed(dev);
-               dev_priv->skl_vco_freq = skl_cdclk_get_vco(cdclk_freq);
                if (skl_sanitize_cdclk(dev_priv))
                        DRM_DEBUG_KMS("Sanitized cdclk programmed by pre-os\n");
-               if (!(I915_READ(LCPLL1_CTL) & LCPLL_PLL_ENABLE))
-                       DRM_ERROR("LCPLL1 is disabled\n");
        } else if (!IS_BROXTON(dev_priv)) {
                /*
                 * The LCPLL register should be turned on by the BIOS. For now