[PATCH 63/89] drm/i915/skl: Define shared DPLLs for Skylake

Damien Lespiau
2014-09-04T11:28:58Z

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

On skylake, DPLL 1, 2 and 3 can be used for DP and HDMI. The shared dpll
framework allows us to share those DPLLs among DDIs when possible.

The most tricky part is to provide a DPLL state that can be easily
compared. DPLL_CRTL1 is shared by all the DPLLs, 6 bits each. The
per-dpll crtl1 field of the hw state is then normalized to be the same
value if 2 DPLLs do indeed have identical values for those 6 bits.

v2: Port the code to the shared DPLL infrastructure (Damien)

XXX: This patch would benefit from a bunchf of macros for handling ctrl1
to encapsulate the masking and shifting (Daniel)

Signed-off-by: Satheeshakrishna M <satheeshakrishna.m@intel.com> (v1)
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
---
drivers/gpu/drm/i915/i915_drv.h | 11 ++++
drivers/gpu/drm/i915/intel_ddi.c | 126 ++++++++++++++++++++++++++++++++++++++-
2 files changed, 136 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 65e5ffb..a6e14db 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -225,6 +225,17 @@ struct intel_dpll_hw_state {

/* hsw, bdw */
uint32_t wrpll;
+
+ /* skl */
+ /*
+ * DPLL_CTRL1 has 6 bits for each each this DPLL. We store those in
+ * lower part of crtl1 and they get shifted into position when writing
+ * the register. This allows us to easily compare the state to share
+ * the DPLL.
+ */
+ uint32_t ctrl1;
+ /* HDMI only, 0 when used for DP */
+ uint32_t cfgcr1, cfgcr2;
};

struct intel_shared_dpll {
diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index b5cfb07..53ac23d 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -1522,12 +1522,136 @@ static void hsw_shared_dplls_init(struct drm_i915_private *dev_priv)
}
}

+static const char * const skl_ddi_pll_names[] = {
+ "DPLL 1",
+ "DPLL 2",
+ "DPLL 3",
+};
+
+struct skl_dpll_regs {
+ u32 ctl, cfgcr1, cfgcr2;
+};
+
+/* this array is indexed by the *shared* pll id */
+static const struct skl_dpll_regs skl_dpll_regs[3] = {
+ {
+ /* DPLL 1 */
+ .ctl = LCPLL2_CTL,
+ .cfgcr1 = DPLL1_CFGCR1,
+ .cfgcr2 = DPLL1_CFGCR2,
+ },
+ {
+ /* DPLL 2 */
+ .ctl = WRPLL_CTL1,
+ .cfgcr1 = DPLL2_CFGCR1,
+ .cfgcr2 = DPLL2_CFGCR2,
+ },
+ {
+ /* DPLL 3 */
+ .ctl = WRPLL_CTL2,
+ .cfgcr1 = DPLL3_CFGCR1,
+ .cfgcr2 = DPLL3_CFGCR2,
+ },
+};
+
+static void skl_ddi_pll_enable(struct drm_i915_private *dev_priv,
+ struct intel_shared_dpll *pll)
+{
+ uint32_t val;
+ unsigned int dpll;
+ const struct skl_dpll_regs *regs = skl_dpll_regs;
+
+ /* DPLL0 is not part of the shared DPLLs, so pll->id is 0 for DPLL1 */
+ dpll = pll->id + 1;
+
+ val = I915_READ(DPLL_CTRL1);
+
+ val &= ~(DPLL_CTRL1_HDMI_MODE(dpll) | DPLL_CTRL1_SSC(dpll) |
+ DPLL_CRTL1_LINK_RATE_MASK(dpll));
+ val |= pll->hw_state.ctrl1 << (dpll * 6);
+
+ I915_WRITE(DPLL_CTRL1, val);
+ POSTING_READ(DPLL_CTRL1);
+
+ I915_WRITE(regs[pll->id].cfgcr1, pll->hw_state.cfgcr1);
+ I915_WRITE(regs[pll->id].cfgcr2, pll->hw_state.cfgcr2);
+ POSTING_READ(regs[pll->id].cfgcr1);
+ POSTING_READ(regs[pll->id].cfgcr2);
+
+ /* the enable bit is always bit 31 */
+ I915_WRITE(regs[pll->id].ctl,
+ I915_READ(regs[pll->id].ctl) | LCPLL_PLL_ENABLE);
+
+ if (wait_for(I915_READ(DPLL_STATUS) & DPLL_LOCK(dpll), 5))
+ DRM_ERROR("DPLL %d not locked\n", dpll);
+}
+
+static void skl_ddi_pll_disable(struct drm_i915_private *dev_priv,
+ struct intel_shared_dpll *pll)
+{
+ const struct skl_dpll_regs *regs = skl_dpll_regs;
+
+ /* the enable bit is always bit 31 */
+ I915_WRITE(regs[pll->id].ctl,
+ I915_READ(regs[pll->id].ctl) & ~LCPLL_PLL_ENABLE);
+ POSTING_READ(regs[pll->id].ctl);
+}
+
+static bool skl_ddi_pll_get_hw_state(struct drm_i915_private *dev_priv,
+ struct intel_shared_dpll *pll,
+ struct intel_dpll_hw_state *hw_state)
+{
+ uint32_t val;
+ unsigned int dpll;
+ const struct skl_dpll_regs *regs = skl_dpll_regs;
+
+ if (!intel_display_power_enabled(dev_priv, POWER_DOMAIN_PLLS))
+ return false;
+
+ /* DPLL0 is not part of the shared DPLLs, so pll->id is 0 for DPLL1 */
+ dpll = pll->id + 1;
+
+ val = I915_READ(regs[pll->id].ctl);
+ if (!(val & LCPLL_PLL_ENABLE))
+ return false;
+
+ val = I915_READ(DPLL_CTRL1);
+ hw_state->ctrl1 = (val >> (dpll * 6)) & 0x3f;
+
+ /* avoid reading back stale values if HDMI mode is not enabled */
+ if (val & DPLL_CTRL1_HDMI_MODE(dpll)) {
+ hw_state->cfgcr1 = I915_READ(regs[pll->id].cfgcr1);
+ hw_state->cfgcr2 = I915_READ(regs[pll->id].cfgcr2);
+ }
+
+ return true;
+}
+
+static void skl_shared_dplls_init(struct drm_i915_private *dev_priv)
+{
+ int i;
+
+ dev_priv->num_shared_dpll = 3;
+
+ for (i = 0; i < dev_priv->num_shared_dpll; i++) {
+ dev_priv->shared_dplls[i].id = i;
+ dev_priv->shared_dplls[i].name = skl_ddi_pll_names[i];
+ dev_priv->shared_dplls[i].disable = skl_ddi_pll_disable;
+ dev_priv->shared_dplls[i].enable = skl_ddi_pll_enable;
+ dev_priv->shared_dplls[i].get_hw_state =
+ skl_ddi_pll_get_hw_state;
+ }
+}
+
void intel_ddi_pll_init(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
uint32_t val = I915_READ(LCPLL_CTL);

- hsw_shared_dplls_init(dev_priv);
+ if (IS_SKYLAKE(dev))
+ skl_shared_dplls_init(dev_priv);
+ else
+ hsw_shared_dplls_init(dev_priv);

DRM_DEBUG_KMS("CDCLK running at %dKHz\n",
intel_ddi_get_cdclk_freq(dev_priv));
--
1.8.3.1