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

Paulo Zanoni
2014-09-23T14:28:13Z

2014-09-04 8:27 GMT-03:00 Damien Lespiau <damien.lespiau@intel.com>:
> 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)

Are you planning to do the XXX above before merging?

The only suspect thing is that the spec doesn't mention
if/when/how-much we need to sleep after enabling the clocks... I hope
this won't be a problem later :)

Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>

>
> 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
>
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--
Paulo Zanoni