Re: [PATCH] drm/i915/ehl: Add support for DPLL4 (v4)

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Thu, Apr 11, 2019 at 04:36:00PM -0700, Vivek Kasireddy wrote:
> This patch adds support for DPLL4 on EHL that include the
> following restrictions:
> 
> - DPLL4 cannot be used with DDIA (combo port A internal eDP usage).
>   DPLL4 can be used with other DDIs, including DDID
>   (combo port A external usage).
> 
> - DPLL4 cannot be enabled when DC5 or DC6 are enabled.
> 
> - The DPLL4 enable, lock, power enabled, and power state are connected
>   to the MGPLL1_ENABLE register.
> 
> v2: (suggestions from Bob Paauwe)
> - Rework ehl_get_dpll() function to call intel_find_shared_dpll() and
>   iterate twice: once for Combo plls and once for MG plls.
> 
> - Use MG pll funcs for DPLL4 instead of creating new ones and modify
>   mg_pll_enable to include the restrictions for EHL.
> 
> v3: Fix compilation error
> 
> v4: (suggestions from Lucas and Ville)
> - Treat DPLL4 as a combo phy PLL and not as MG PLL
> - Disable DC states when this DPLL is being enabled
> - Reuse icl_get_dpll instead of creating a separate one for EHL
> 
> Cc: Lucas De Marchi <lucas.demarchi@intel.com>
> Cc: José Roberto de Souza <jose.souza@intel.com>
> Cc: Bob Paauwe <bob.j.paauwe@intel.com>
> Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_dpll_mgr.c | 35 ++++++++++++++++++++++++++++++++---
>  drivers/gpu/drm/i915/intel_dpll_mgr.h |  4 ++++
>  2 files changed, 36 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dpll_mgr.c b/drivers/gpu/drm/i915/intel_dpll_mgr.c
> index e01c057ce50b..207af4af4978 100644
> --- a/drivers/gpu/drm/i915/intel_dpll_mgr.c
> +++ b/drivers/gpu/drm/i915/intel_dpll_mgr.c
> @@ -2825,6 +2825,12 @@ icl_get_dpll(struct intel_crtc_state *crtc_state,
>  	if (intel_port_is_combophy(dev_priv, port)) {
>  		min = DPLL_ID_ICL_DPLL0;
>  		max = DPLL_ID_ICL_DPLL1;
> +
> +		if (IS_ELKHARTLAKE(dev_priv)) {
> +			if (encoder->type != INTEL_OUTPUT_EDP)
> +				max = DPLL_ID_EHL_DPLL4;
> +		}
> +
>  		ret = icl_calc_dpll_state(crtc_state, encoder);
>  	} else if (intel_port_is_tc(dev_priv, port)) {
>  		if (encoder->type == INTEL_OUTPUT_DP_MST) {
> @@ -2964,8 +2970,14 @@ static bool combo_pll_get_hw_state(struct drm_i915_private *dev_priv,
>  				   struct intel_shared_dpll *pll,
>  				   struct intel_dpll_hw_state *hw_state)
>  {
> -	return icl_pll_get_hw_state(dev_priv, pll, hw_state,
> -				    CNL_DPLL_ENABLE(pll->info->id));
> +	i915_reg_t enable_reg = CNL_DPLL_ENABLE(pll->info->id);
> +
> +	if (IS_ELKHARTLAKE(dev_priv) &&
> +	    pll->info->id == DPLL_ID_EHL_DPLL4) {
> +		enable_reg = MG_PLL_ENABLE(0);
> +	}
> +
> +	return icl_pll_get_hw_state(dev_priv, pll, hw_state, enable_reg);
>  }
>  
>  static bool tbt_pll_get_hw_state(struct drm_i915_private *dev_priv,
> @@ -3076,6 +3088,14 @@ static void combo_pll_enable(struct drm_i915_private *dev_priv,
>  {
>  	i915_reg_t enable_reg = CNL_DPLL_ENABLE(pll->info->id);
>  
> +	if (IS_ELKHARTLAKE(dev_priv) &&
> +	    pll->info->id == DPLL_ID_EHL_DPLL4) {
> +		enable_reg = MG_PLL_ENABLE(0);
> +
> +		/* Need to disable DC states when this DPLL is enabled. */
> +		bxt_disable_dc9(dev_priv);

You can't simply call that from random places. It needs to be handled by
the power domain stuff.

> +	}
> +
>  	icl_pll_power_enable(dev_priv, pll, enable_reg);
>  
>  	icl_dpll_write(dev_priv, pll);
> @@ -3171,7 +3191,15 @@ static void icl_pll_disable(struct drm_i915_private *dev_priv,
>  static void combo_pll_disable(struct drm_i915_private *dev_priv,
>  			      struct intel_shared_dpll *pll)
>  {
> -	icl_pll_disable(dev_priv, pll, CNL_DPLL_ENABLE(pll->info->id));
> +	i915_reg_t enable_reg = CNL_DPLL_ENABLE(pll->info->id);
> +
> +	if (IS_ELKHARTLAKE(dev_priv) &&
> +	    pll->info->id == DPLL_ID_EHL_DPLL4) {
> +		enable_reg = MG_PLL_ENABLE(0);
> +		bxt_enable_dc9(dev_priv);
> +	}
> +
> +	icl_pll_disable(dev_priv, pll, enable_reg);
>  }
>  
>  static void tbt_pll_disable(struct drm_i915_private *dev_priv,
> @@ -3249,6 +3277,7 @@ static const struct intel_dpll_mgr icl_pll_mgr = {
>  static const struct dpll_info ehl_plls[] = {
>  	{ "DPLL 0", &combo_pll_funcs, DPLL_ID_ICL_DPLL0, 0 },
>  	{ "DPLL 1", &combo_pll_funcs, DPLL_ID_ICL_DPLL1, 0 },
> +	{ "DPLL 4", &combo_pll_funcs, DPLL_ID_EHL_DPLL4, 0 },
>  	{ },
>  };
>  
> diff --git a/drivers/gpu/drm/i915/intel_dpll_mgr.h b/drivers/gpu/drm/i915/intel_dpll_mgr.h
> index bd8124cc81ed..f3f99929cee8 100644
> --- a/drivers/gpu/drm/i915/intel_dpll_mgr.h
> +++ b/drivers/gpu/drm/i915/intel_dpll_mgr.h
> @@ -113,6 +113,10 @@ enum intel_dpll_id {
>  	 * @DPLL_ID_ICL_DPLL1: ICL combo PHY DPLL1
>  	 */
>  	DPLL_ID_ICL_DPLL1 = 1,
> +	/**
> +	 * @DPLL_ID_EHL_DPLL4: EHL combo PHY DPLL4
> +	 */
> +	DPLL_ID_EHL_DPLL4 = 2,
>  	/**
>  	 * @DPLL_ID_ICL_TBTPLL: ICL TBT PLL
>  	 */
> -- 
> 2.14.5
> 
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-- 
Ville Syrjälä
Intel
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