[Intel-gfx] [PATCH 6/7] drm/i915: Implement PHY lane power gating for CHV

Deepak S deepak.s at linux.intel.com
Fri May 8 22:35:27 PDT 2015



On Friday 08 May 2015 09:35 PM, Ville Syrjälä wrote:
> On Fri, May 08, 2015 at 08:19:12PM +0530, Deepak S wrote:
>>
>> On Friday 10 April 2015 08:51 PM, ville.syrjala at linux.intel.com wrote:
>>> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>>>
>>> Powergate the PHY lanes when they're not needed. For HDMI all four lanes
>>> are needed always, but for DP we can enable only the needed lanes. And
>>> when the port is not used all lanes can be power gated. This could
>>> reduce power consumption a bit when only a subset of the lanes in the
>>> PHY are required.
>>>
>>> A bit of extra care is needed to reconstruct the initial state of the
>>> DPIO_PHY_CONTROL register since we can't read it. So instead we read the
>>> actual lane status from the DPLL/PHY_STATUS registers and use that to
>>> determine which lanes ought to be powergated initially.
>>>
>>> Also sprinkle a few debug prints around so that we can monitor the
>>> DPIO_PHY_STATUS changes without having to read it and risk corrupting
>>> it.
>>>
>>> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
>>> ---
>>>    drivers/gpu/drm/i915/i915_reg.h         |  2 +
>>>    drivers/gpu/drm/i915/intel_dp.c         |  8 ++++
>>>    drivers/gpu/drm/i915/intel_drv.h        |  2 +
>>>    drivers/gpu/drm/i915/intel_hdmi.c       |  5 +++
>>>    drivers/gpu/drm/i915/intel_runtime_pm.c | 69 +++++++++++++++++++++++++++++++--
>>>    5 files changed, 82 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
>>> index 977bad6..34c366a 100644
>>> --- a/drivers/gpu/drm/i915/i915_reg.h
>>> +++ b/drivers/gpu/drm/i915/i915_reg.h
>>> @@ -1887,10 +1887,12 @@ enum skl_disp_power_wells {
>>>    #define DPIO_PHY_STATUS			(VLV_DISPLAY_BASE + 0x6240)
>>>    #define   DPLL_PORTD_READY_MASK		(0xf)
>>>    #define DISPLAY_PHY_CONTROL (VLV_DISPLAY_BASE + 0x60100)
>>> +#define   PHY_CH_POWER_DOWN_OVRD_EN(phy, ch)	(1 << (2*(phy)+(ch)+27))
>>>    #define   PHY_LDO_DELAY_0NS			0x0
>>>    #define   PHY_LDO_DELAY_200NS			0x1
>>>    #define   PHY_LDO_DELAY_600NS			0x2
>>>    #define   PHY_LDO_SEQ_DELAY(delay, phy)		((delay) << (2*(phy)+23))
>>> +#define   PHY_CH_POWER_DOWN_OVRD(mask, phy, ch)	((mask) << (8*(phy)+4*(ch)+11))
>>>    #define   PHY_CH_SU_PSR				0x1
>>>    #define   PHY_CH_DEEP_PSR			0x7
>>>    #define   PHY_CH_POWER_MODE(mode, phy, ch)	((mode) << (6*(phy)+3*(ch)+2))
>>> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
>>> index ac38fd8..0b43f99 100644
>>> --- a/drivers/gpu/drm/i915/intel_dp.c
>>> +++ b/drivers/gpu/drm/i915/intel_dp.c
>>> @@ -2336,6 +2336,8 @@ static void chv_post_disable_dp(struct intel_encoder *encoder)
>>>    
>>>    	intel_dp_link_down(intel_dp);
>>>    
>>> +	chv_powergate_phy_lanes(encoder, 0xf);
>>> +
>>>    	mutex_lock(&dev_priv->dpio_lock);
>>>    
>>>    	/* Propagate soft reset to data lane reset */
>>> @@ -2482,6 +2484,12 @@ static void intel_enable_dp(struct intel_encoder *encoder)
>>>    	if (IS_VALLEYVIEW(dev))
>>>    		vlv_init_panel_power_sequencer(intel_dp);
>>>    
>>> +	if (IS_CHERRYVIEW(dev)) {
>>> +		/* FIXME deal with lane reversal */
>>> +		lane_mask = 0xf & ~((1 << intel_dp->lane_count) - 1);
>>> +		chv_powergate_phy_lanes(encoder, lane_mask);
>>> +	}
>>> +
>>>    	intel_dp_enable_port(intel_dp);
>>>    
>>>    	edp_panel_vdd_on(intel_dp);
>>> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
>>> index 3ec829a..54bcca8 100644
>>> --- a/drivers/gpu/drm/i915/intel_drv.h
>>> +++ b/drivers/gpu/drm/i915/intel_drv.h
>>> @@ -1238,6 +1238,8 @@ void intel_runtime_pm_put(struct drm_i915_private *dev_priv);
>>>    
>>>    void intel_display_set_init_power(struct drm_i915_private *dev, bool enable);
>>>    
>>> +void chv_powergate_phy_lanes(struct intel_encoder *encoder, unsigned int mask);
>>> +
>>>    /* intel_pm.c */
>>>    void intel_init_clock_gating(struct drm_device *dev);
>>>    void intel_suspend_hw(struct drm_device *dev);
>>> diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
>>> index 24b0aa1..f5842c3 100644
>>> --- a/drivers/gpu/drm/i915/intel_hdmi.c
>>> +++ b/drivers/gpu/drm/i915/intel_hdmi.c
>>> @@ -916,6 +916,9 @@ static void intel_disable_hdmi(struct intel_encoder *encoder)
>>>    		I915_WRITE(intel_hdmi->hdmi_reg, temp);
>>>    		POSTING_READ(intel_hdmi->hdmi_reg);
>>>    	}
>>> +
>>> +	if (IS_CHERRYVIEW(dev))
>>> +		chv_powergate_phy_lanes(encoder, 0xf);
>>>    }
>>>    
>>>    static int hdmi_portclock_limit(struct intel_hdmi *hdmi, bool respect_dvi_limit)
>>> @@ -1634,6 +1637,8 @@ static void chv_hdmi_pre_enable(struct intel_encoder *encoder)
>>>    				   intel_crtc->config->has_hdmi_sink,
>>>    				   adjusted_mode);
>>>    
>>> +	chv_powergate_phy_lanes(encoder, 0x0);
>>> +
>>>    	intel_enable_hdmi(encoder);
>>>    
>>>    	vlv_wait_port_ready(dev_priv, dport, 0x0);
>>> diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
>>> index 5cd8a51..d9e00d3 100644
>>> --- a/drivers/gpu/drm/i915/intel_runtime_pm.c
>>> +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
>>> @@ -668,6 +668,9 @@ static void chv_dpio_cmn_power_well_enable(struct drm_i915_private *dev_priv,
>>>    
>>>    	dev_priv->chv_phy_control |= PHY_COM_LANE_RESET_DEASSERT(phy);
>>>    	I915_WRITE(DISPLAY_PHY_CONTROL, dev_priv->chv_phy_control);
>>> +
>>> +	DRM_DEBUG_KMS("Enabled DPIO PHY%d (DPIO_PHY_CONTROL=0x%08x)\n",
>>> +		      phy, dev_priv->chv_phy_control);
>>>    }
>>>    
>>>    static void chv_dpio_cmn_power_well_disable(struct drm_i915_private *dev_priv,
>>> @@ -680,10 +683,15 @@ static void chv_dpio_cmn_power_well_disable(struct drm_i915_private *dev_priv,
>>>    
>>>    	if (power_well->data == PUNIT_POWER_WELL_DPIO_CMN_BC) {
>>>    		phy = DPIO_PHY0;
>>> +		dev_priv->chv_phy_control |=
>>> +			PHY_CH_POWER_DOWN_OVRD(0xf, phy, DPIO_CH0) |
>>> +			PHY_CH_POWER_DOWN_OVRD(0xf, phy, DPIO_CH1);
>>>    		assert_pll_disabled(dev_priv, PIPE_A);
>>>    		assert_pll_disabled(dev_priv, PIPE_B);
>>>    	} else {
>>>    		phy = DPIO_PHY1;
>>> +		dev_priv->chv_phy_control |=
>>> +			PHY_CH_POWER_DOWN_OVRD(0xf, phy, DPIO_CH0);
>>>    		assert_pll_disabled(dev_priv, PIPE_C);
>>>    	}
>>>    
>>> @@ -691,6 +699,25 @@ static void chv_dpio_cmn_power_well_disable(struct drm_i915_private *dev_priv,
>>>    	I915_WRITE(DISPLAY_PHY_CONTROL, dev_priv->chv_phy_control);
>>>    
>>>    	vlv_set_power_well(dev_priv, power_well, false);
>>> +
>>> +	DRM_DEBUG_KMS("Disabled DPIO PHY%d (DPIO_PHY_CONTROL=0x%08x)\n",
>>> +		      phy, dev_priv->chv_phy_control);
>>> +}
>>> +
>>> +void chv_powergate_phy_lanes(struct intel_encoder *encoder, unsigned int mask)
>>> +{
>>> +	struct drm_device *dev = encoder->base.dev;
>>> +	struct drm_i915_private *dev_priv = dev->dev_private;
>>> +	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
>>> +	enum dpio_phy phy = DPIO_PHY(intel_crtc->pipe);
>>> +	enum dpio_channel ch = vlv_dport_to_channel(enc_to_dig_port(&encoder->base));
>>> +
>>> +	dev_priv->chv_phy_control &= ~PHY_CH_POWER_DOWN_OVRD(0xf, phy, ch);
>>> +	dev_priv->chv_phy_control |= PHY_CH_POWER_DOWN_OVRD(mask, phy, ch);
>>> +	I915_WRITE(DISPLAY_PHY_CONTROL, dev_priv->chv_phy_control);
>>> +
>>> +	DRM_DEBUG_KMS("Power gating DPIO PHY%d CH%d lanes 0x%x (DPIO_PHY_CONTROL=0x%08x)\n",
>>> +		      phy, ch, mask, dev_priv->chv_phy_control);
>>>    }
>>>    
>> Hi Ville,
>>
>> I think based on the spec, we needto program 0x8170 as 0xxxC3xxxx to affect the DDI0 power down
>> and this reigster to be programted beforeDPIO_PHY_CONTROL ?
> Doh. Nice catch. Looks like the dynamic power down bits default to off.
> I also found the same bit in CL2 DW6, which isn't mentioned by the spec.
> I'll cook up a patch to flip them and run a few tests to see if stuff
> still works.

Ok Thanks
One more Q. I think we need to re-program phy lanes power down override /enable values after power gating/ungating PHY0/1?

>
>> Thanks
>> Deepak
>>
>>>    static bool chv_pipe_power_well_enabled(struct drm_i915_private *dev_priv,
>>> @@ -1402,19 +1429,53 @@ static void chv_phy_control_init(struct drm_i915_private *dev_priv)
>>>    	 * DISPLAY_PHY_CONTROL can get corrupted if read. As a
>>>    	 * workaround never ever read DISPLAY_PHY_CONTROL, and
>>>    	 * instead maintain a shadow copy ourselves. Use the actual
>>> -	 * power well state to reconstruct the expected initial
>>> -	 * value.
>>> +	 * power well state and lane status to reconstruct the
>>> +	 * expected initial value.
>>>    	 */
>>>    	dev_priv->chv_phy_control =
>>> +		PHY_CH_POWER_DOWN_OVRD_EN(DPIO_PHY0, DPIO_CH0) |
>>> +		PHY_CH_POWER_DOWN_OVRD_EN(DPIO_PHY0, DPIO_CH1) |
>>> +		PHY_CH_POWER_DOWN_OVRD_EN(DPIO_PHY1, DPIO_CH0) |
>>>    		PHY_LDO_SEQ_DELAY(PHY_LDO_DELAY_600NS, DPIO_PHY0) |
>>>    		PHY_LDO_SEQ_DELAY(PHY_LDO_DELAY_600NS, DPIO_PHY1) |
>>>    		PHY_CH_POWER_MODE(PHY_CH_SU_PSR, DPIO_PHY0, DPIO_CH0) |
>>>    		PHY_CH_POWER_MODE(PHY_CH_SU_PSR, DPIO_PHY0, DPIO_CH1) |
>>>    		PHY_CH_POWER_MODE(PHY_CH_SU_PSR, DPIO_PHY1, DPIO_CH0);
>>> -	if (cmn_bc->ops->is_enabled(dev_priv, cmn_bc))
>>> +
>>> +	if (cmn_bc->ops->is_enabled(dev_priv, cmn_bc)) {
>>> +		uint32_t status = I915_READ(DPLL(PIPE_A));
>>> +		unsigned int mask;
>>> +
>>> +		mask = status & DPLL_PORTB_READY_MASK;
>>> +		dev_priv->chv_phy_control |=
>>> +			PHY_CH_POWER_DOWN_OVRD(mask, DPIO_PHY0, DPIO_CH0);
>>> +		mask = (status & DPLL_PORTC_READY_MASK) >> 4;
>>> +		dev_priv->chv_phy_control |=
>>> +			PHY_CH_POWER_DOWN_OVRD(mask, DPIO_PHY0, DPIO_CH1);
>>> +
>>>    		dev_priv->chv_phy_control |= PHY_COM_LANE_RESET_DEASSERT(DPIO_PHY0);
>>> -	if (cmn_d->ops->is_enabled(dev_priv, cmn_d))
>>> +	} else {
>>> +		dev_priv->chv_phy_control |=
>>> +			PHY_CH_POWER_DOWN_OVRD(0xf, DPIO_PHY0, DPIO_CH0) |
>>> +			PHY_CH_POWER_DOWN_OVRD(0xf, DPIO_PHY0, DPIO_CH1);
>>> +	}
>>> +
>>> +	if (cmn_d->ops->is_enabled(dev_priv, cmn_d)) {
>>> +		uint32_t status = I915_READ(DPIO_PHY_STATUS);
>>> +		unsigned int mask;
>>> +
>>> +		mask = status & DPLL_PORTD_READY_MASK;
>>> +		dev_priv->chv_phy_control |=
>>> +			PHY_CH_POWER_DOWN_OVRD(mask, DPIO_PHY1, DPIO_CH0);
>>> +
>>>    		dev_priv->chv_phy_control |= PHY_COM_LANE_RESET_DEASSERT(DPIO_PHY1);
>>> +	} else {
>>> +		dev_priv->chv_phy_control |=
>>> +			PHY_CH_POWER_DOWN_OVRD(0xf, DPIO_PHY1, DPIO_CH0);
>>> +	}
>>> +
>>> +	DRM_DEBUG_KMS("Initial DPIO_PHY_CONTROL=0x%08x\n",
>>> +		      dev_priv->chv_phy_control);
>>>    }
>>>    
>>>    static void vlv_cmnlane_wa(struct drm_i915_private *dev_priv)
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