Re: [Intel-gfx] [PATCH v4 4/9] drm/i915/tc/icl: Implement TC cold sequences

[Imre Deak <imre.deak@intel.com>]

On Mon, Apr 13, 2020 at 09:45:10AM -0700, José Roberto de Souza wrote:
> This is required for legacy/static TC ports as IOM is not aware of
> the connection and will not trigger the TC cold exit.
> 
> Just request PCODE to exit TCCOLD is not enough as it could enter
> again before driver makes use of the port, to prevent it BSpec states
> that aux powerwell should be held.
> 
> So here embedding the TC cold exit sequence into ICL aux enable,
> it will enable aux and then request TC cold to exit.
> 
> The TC cold block(exit and aux hold) and unblock was added to some
> exported TC functions for the others and to access PHY registers,
> callers should enable and keep aux powerwell enabled during access.
> 
> Also adding TC cold check and warnig in tc_port_load_fia_params() as
> at this point of the driver initialization we can't request power
> wells, if we get this warning we will need to figure out how to handle
> it.
> 
> v2:
> - moved ICL TC cold exit function to intel_display_power
> - using dig_port->tc_legacy_port to only execute sequences for legacy
> ports, hopefully VBTs will have this right
> - fixed check to call _hsw_power_well_continue_enable()
> - calling _hsw_power_well_continue_enable() unconditionally in
> icl_tc_phy_aux_power_well_enable(), if needed we will surpress timeout
> warnings of TC legacy ports
> - only blocking TC cold around fia access
> 
> v3:
> - added timeout of 5msec to not loop forever if
> sandybridge_pcode_write_timeout() keeps returning -EAGAIN
> returning -EAGAIN in in icl_tc_cold_exit()
> - removed leftover tc_cold_wakeref
> - added one msec sleep when PCODE returns -EAGAIN
> 
> v4:
> - removed 5msec timeout, instead giving 1msec to whoever is using
> PCODE to finish it up to 3 times
> - added a comment about turn TC cold exit failure as a error in future
> 
> BSpec: 21750
> Fixes: https://gitlab.freedesktop.org/drm/intel/issues/1296
> Cc: Imre Deak <imre.deak@intel.com>
> Cc: Cooper Chiou <cooper.chiou@intel.com>
> Cc: Kai-Heng Feng <kai.heng.feng@canonical.com>
> Signed-off-by: José Roberto de Souza <jose.souza@intel.com>

Reviewed-by: Imre Deak <imre.deak@intel.com>

> ---
>  .../drm/i915/display/intel_display_power.c    | 25 +++++++-
>  drivers/gpu/drm/i915/display/intel_tc.c       | 64 +++++++++++++++++--
>  drivers/gpu/drm/i915/i915_reg.h               |  1 +
>  3 files changed, 83 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display_power.c b/drivers/gpu/drm/i915/display/intel_display_power.c
> index 5bef7dda4a7a..e2dddaf1051b 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_power.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_power.c
> @@ -575,6 +575,28 @@ static void icl_tc_port_assert_ref_held(struct drm_i915_private *dev_priv,
>  
>  #define TGL_AUX_PW_TO_TC_PORT(pw_idx)	((pw_idx) - TGL_PW_CTL_IDX_AUX_TC1)
>  
> +static void icl_tc_cold_exit(struct drm_i915_private *i915)
> +{
> +	int ret, tries = 0;
> +
> +	while (1) {
> +		ret = sandybridge_pcode_write_timeout(i915,
> +						      ICL_PCODE_EXIT_TCCOLD,
> +						      0, 250, 1);
> +		if (ret != -EAGAIN || ++tries == 3)
> +			break;
> +		msleep(1);
> +	}
> +
> +	/* Spec states that TC cold exit can take up to 1ms to complete */
> +	if (!ret)
> +		msleep(1);
> +
> +	/* TODO: turn failure into a error as soon i915 CI updates ICL IFWI */
> +	drm_dbg_kms(&i915->drm, "TC cold block %s\n", ret ? "failed" :
> +		    "succeeded");
> +}
> +
>  static void
>  icl_tc_phy_aux_power_well_enable(struct drm_i915_private *dev_priv,
>  				 struct i915_power_well *power_well)
> @@ -593,7 +615,8 @@ icl_tc_phy_aux_power_well_enable(struct drm_i915_private *dev_priv,
>  
>  	hsw_power_well_enable_prepare(dev_priv, power_well);
>  
> -	/* TODO ICL TC cold handling */
> +	if (INTEL_GEN(dev_priv) == 11 && dig_port->tc_legacy_port)
> +		icl_tc_cold_exit(dev_priv);
>  
>  	hsw_power_well_enable_complete(dev_priv, power_well);
>  
> diff --git a/drivers/gpu/drm/i915/display/intel_tc.c b/drivers/gpu/drm/i915/display/intel_tc.c
> index 275618bedf32..0cf33d4d21c3 100644
> --- a/drivers/gpu/drm/i915/display/intel_tc.c
> +++ b/drivers/gpu/drm/i915/display/intel_tc.c
> @@ -34,6 +34,7 @@ tc_port_load_fia_params(struct drm_i915_private *i915,
>  	if (INTEL_INFO(i915)->display.has_modular_fia) {
>  		modular_fia = intel_uncore_read(&i915->uncore,
>  						PORT_TX_DFLEXDPSP(FIA1));
> +		drm_WARN_ON(&i915->drm, modular_fia == 0xffffffff);
>  		modular_fia &= MODULAR_FIA_MASK;
>  	} else {
>  		modular_fia = 0;
> @@ -52,6 +53,37 @@ tc_port_load_fia_params(struct drm_i915_private *i915,
>  	}
>  }
>  
> +static intel_wakeref_t
> +tc_cold_block(struct intel_digital_port *dig_port)
> +{
> +	struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
> +	enum intel_display_power_domain domain;
> +
> +	if (INTEL_GEN(i915) != 11 || !dig_port->tc_legacy_port)
> +		return 0;
> +
> +	domain = intel_legacy_aux_to_power_domain(dig_port->aux_ch);
> +	return intel_display_power_get(i915, domain);
> +}
> +
> +static void
> +tc_cold_unblock(struct intel_digital_port *dig_port, intel_wakeref_t wakeref)
> +{
> +	struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
> +	enum intel_display_power_domain domain;
> +
> +	/*
> +	 * wakeref == -1, means some error happened saving save_depot_stack but
> +	 * power should still be put down and 0 is a invalid save_depot_stack
> +	 * id so can be used to skip it for non TC legacy ports.
> +	 */
> +	if (wakeref == 0)
> +		return;
> +
> +	domain = intel_legacy_aux_to_power_domain(dig_port->aux_ch);
> +	intel_display_power_put_async(i915, domain, wakeref);
> +}
> +
>  u32 intel_tc_port_get_lane_mask(struct intel_digital_port *dig_port)
>  {
>  	struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
> @@ -420,9 +452,14 @@ static void intel_tc_port_reset_mode(struct intel_digital_port *dig_port,
>  	enum tc_port_mode old_tc_mode = dig_port->tc_mode;
>  
>  	intel_display_power_flush_work(i915);
> -	drm_WARN_ON(&i915->drm,
> -		    intel_display_power_is_enabled(i915,
> -					intel_aux_power_domain(dig_port)));
> +	if (INTEL_GEN(i915) != 11 || !dig_port->tc_legacy_port) {
> +		enum intel_display_power_domain aux_domain;
> +		bool aux_powered;
> +
> +		aux_domain = intel_aux_power_domain(dig_port);
> +		aux_powered = intel_display_power_is_enabled(i915, aux_domain);
> +		drm_WARN_ON(&i915->drm, aux_powered);
> +	}
>  
>  	icl_tc_phy_disconnect(dig_port);
>  	icl_tc_phy_connect(dig_port, required_lanes);
> @@ -445,9 +482,11 @@ void intel_tc_port_sanitize(struct intel_digital_port *dig_port)
>  {
>  	struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
>  	struct intel_encoder *encoder = &dig_port->base;
> +	intel_wakeref_t tc_cold_wref;
>  	int active_links = 0;
>  
>  	mutex_lock(&dig_port->tc_lock);
> +	tc_cold_wref = tc_cold_block(dig_port);
>  
>  	dig_port->tc_mode = intel_tc_port_get_current_mode(dig_port);
>  	if (dig_port->dp.is_mst)
> @@ -473,6 +512,7 @@ void intel_tc_port_sanitize(struct intel_digital_port *dig_port)
>  		    dig_port->tc_port_name,
>  		    tc_port_mode_name(dig_port->tc_mode));
>  
> +	tc_cold_unblock(dig_port, tc_cold_wref);
>  	mutex_unlock(&dig_port->tc_lock);
>  }
>  
> @@ -494,10 +534,15 @@ static bool intel_tc_port_needs_reset(struct intel_digital_port *dig_port)
>  bool intel_tc_port_connected(struct intel_digital_port *dig_port)
>  {
>  	bool is_connected;
> +	intel_wakeref_t tc_cold_wref;
>  
>  	intel_tc_port_lock(dig_port);
> +	tc_cold_wref = tc_cold_block(dig_port);
> +
>  	is_connected = tc_port_live_status_mask(dig_port) &
>  		       BIT(dig_port->tc_mode);
> +
> +	tc_cold_unblock(dig_port, tc_cold_wref);
>  	intel_tc_port_unlock(dig_port);
>  
>  	return is_connected;
> @@ -513,9 +558,16 @@ static void __intel_tc_port_lock(struct intel_digital_port *dig_port,
>  
>  	mutex_lock(&dig_port->tc_lock);
>  
> -	if (!dig_port->tc_link_refcount &&
> -	    intel_tc_port_needs_reset(dig_port))
> -		intel_tc_port_reset_mode(dig_port, required_lanes);
> +	if (!dig_port->tc_link_refcount) {
> +		intel_wakeref_t tc_cold_wref;
> +
> +		tc_cold_wref = tc_cold_block(dig_port);
> +
> +		if (intel_tc_port_needs_reset(dig_port))
> +			intel_tc_port_reset_mode(dig_port, required_lanes);
> +
> +		tc_cold_unblock(dig_port, tc_cold_wref);
> +	}
>  
>  	drm_WARN_ON(&i915->drm, dig_port->tc_lock_wakeref);
>  	dig_port->tc_lock_wakeref = wakeref;
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 0b39b9abf8a4..e4667add70b0 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -9108,6 +9108,7 @@ enum {
>  #define     ICL_PCODE_MEM_SS_READ_QGV_POINT_INFO(point)	(((point) << 16) | (0x1 << 8))
>  #define   GEN6_PCODE_READ_D_COMP		0x10
>  #define   GEN6_PCODE_WRITE_D_COMP		0x11
> +#define   ICL_PCODE_EXIT_TCCOLD			0x12
>  #define   HSW_PCODE_DE_WRITE_FREQ_REQ		0x17
>  #define   DISPLAY_IPS_CONTROL			0x19
>              /* See also IPS_CTL */
> -- 
> 2.26.0
> 
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