drm/i915/skl: If needed sanitize bios programmed cdclk
Especially in cases where pre-os does not enable display, cdclk might
not be in sane state. During sanitization initialize cdclk with maximum
value till we get dynamic cdclk support.
v2: Check if BIOS programmed correctly rather than always calling init
- Do validation of programmed cdctl and what it is expected
- Only do slk_init_cdclk if validation failed else reuse BIOS
programmed value
v3: Move the validation logic in a separate sanitize function (Ville)
v4: No need to check LCPLL after sanitize and use max_cdclk_freq instead
of hardcoded value (Ville)
Cc: Imre Deak <imre.deak@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Shobhit Kumar <shobhit.kumar@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1445344992-14658-1-git-send-email-shobhit.kumar@intel.com
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index b918802..f5a3c1e 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5760,6 +5760,37 @@
DRM_ERROR("DBuf power enable timeout\n");
}
+int skl_sanitize_cdclk(struct drm_i915_private *dev_priv)
+{
+ uint32_t lcpll1 = I915_READ(LCPLL1_CTL);
+ uint32_t cdctl = I915_READ(CDCLK_CTL);
+ int freq = dev_priv->skl_boot_cdclk;
+
+ /* Is PLL enabled and locked ? */
+ if (!((lcpll1 & LCPLL_PLL_ENABLE) && (lcpll1 & LCPLL_PLL_LOCK)))
+ goto sanitize;
+
+ /* DPLL okay; verify the cdclock
+ *
+ * Noticed in some instances that the freq selection is correct but
+ * decimal part is programmed wrong from BIOS where pre-os does not
+ * enable display. Verify the same as well.
+ */
+ if (cdctl == ((cdctl & CDCLK_FREQ_SEL_MASK) | skl_cdclk_decimal(freq)))
+ /* All well; nothing to sanitize */
+ return false;
+sanitize:
+ /*
+ * As of now initialize with max cdclk till
+ * we get dynamic cdclk support
+ * */
+ dev_priv->skl_boot_cdclk = dev_priv->max_cdclk_freq;
+ skl_init_cdclk(dev_priv);
+
+ /* we did have to sanitize */
+ return true;
+}
+
/* Adjust CDclk dividers to allow high res or save power if possible */
static void valleyview_set_cdclk(struct drm_device *dev, int cdclk)
{