[PATCH 60/89 v5] drm/i915/skl: CD clock back calculation for SKL

Damien Lespiau
2014-11-04T16:15:59Z

From: Satheeshakrishna M <satheeshakrishna.m@intel.com>

Determine programmed cd clock for SKL.

v2: Fix the LCPLL1 enable warning logic

v3: Rebase over the hsw pll rework.

v4: Rebase on top of the per-platform split (Damien)

v5: Modified as per review comments from Paulo

Signed-off-by: Satheeshakrishna M <satheeshakrishna.m@intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
---
drivers/gpu/drm/i915/intel_ddi.c | 75 +++++++++++++++++++++++++++++++++++-----
1 file changed, 66 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index a49f454..72691ec 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -1276,6 +1276,54 @@ static void intel_disable_ddi(struct intel_encoder *intel_encoder)
}
}

+static int skl_get_cdclk_freq(struct drm_i915_private *dev_priv)
+{
+ uint32_t lcpll1 = I915_READ(LCPLL1_CTL);
+ uint32_t cdctl = I915_READ(CDCLK_CTL);
+ uint32_t linkrate;
+
+ if (!(lcpll1 & LCPLL_PLL_ENABLE)) {
+ WARN(1, "LCPLL1 not enabled\n");
+ return 24000; /* 24MHz is the cd freq with NSSC ref */
+ }
+
+ if ((cdctl & CDCLK_FREQ_SEL_MASK) == CDCLK_FREQ_540)
+ return 540000;
+
+ linkrate = (I915_READ(DPLL_CTRL1) &
+ DPLL_CRTL1_LINK_RATE_MASK(SKL_DPLL0)) >> 1;
+
+ if (linkrate == DPLL_CRTL1_LINK_RATE_2160 ||
+ linkrate == DPLL_CRTL1_LINK_RATE_1080) {
+ /* vco 8640 */
+ switch (cdctl & CDCLK_FREQ_SEL_MASK) {
+ case CDCLK_FREQ_450_432:
+ return 432000;
+ case CDCLK_FREQ_337_308:
+ return 308570;
+ case CDCLK_FREQ_675_617:
+ return 617140;
+ default:
+ WARN(1, "Unknown cd freq selection\n");
+ }
+ } 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_675_617:
+ return 675000;
+ default:
+ WARN(1, "Unknown cd freq selection\n");
+ }
+ }
+
+ /* error case, do as if DPLL0 isn't enabled */
+ return 24000;
+}
+
static int bdw_get_cdclk_freq(struct drm_i915_private *dev_priv)
{
uint32_t lcpll = I915_READ(LCPLL_CTL);
@@ -1317,6 +1365,9 @@ int intel_ddi_get_cdclk_freq(struct drm_i915_private *dev_priv)
{
struct drm_device *dev = dev_priv->dev;

+ if (IS_SKYLAKE(dev))
+ return skl_get_cdclk_freq(dev_priv);
+
if (IS_BROADWELL(dev))
return bdw_get_cdclk_freq(dev_priv);

@@ -1385,19 +1436,25 @@ void intel_ddi_pll_init(struct drm_device *dev)

hsw_shared_dplls_init(dev_priv);

- /* The LCPLL register should be turned on by the BIOS. For now let's
- * just check its state and print errors in case something is wrong.
- * Don't even try to turn it on.
- */
-
DRM_DEBUG_KMS("CDCLK running at %dKHz\n",
intel_ddi_get_cdclk_freq(dev_priv));

- if (val & LCPLL_CD_SOURCE_FCLK)
- DRM_ERROR("CDCLK source is not LCPLL\n");
+ if (IS_SKYLAKE(dev)) {
+ if (!(I915_READ(LCPLL1_CTL) & LCPLL_PLL_ENABLE))
+ DRM_ERROR("LCPLL1 is disabled\n");
+ } else {
+ /*
+ * The LCPLL register should be turned on by the BIOS. For now
+ * let's just check its state and print errors in case
+ * something is wrong. Don't even try to turn it on.
+ */
+
+ if (val & LCPLL_CD_SOURCE_FCLK)
+ DRM_ERROR("CDCLK source is not LCPLL\n");

- if (val & LCPLL_PLL_DISABLE)
- DRM_ERROR("LCPLL is disabled\n");
+ if (val & LCPLL_PLL_DISABLE)
+ DRM_ERROR("LCPLL is disabled\n");
+ }
}

void intel_ddi_prepare_link_retrain(struct drm_encoder *encoder)
--
1.8.3.1

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