[Intel-gfx] [PATCH 05/14] drm/i915/tc: Wait for IOM/FW PHY initialization of legacy TC ports

[Kahola, Mika]

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of Imre
> Deak
> Sent: Thursday, March 16, 2023 3:17 PM
> To: intel-gfx at lists.freedesktop.org
> Subject: [Intel-gfx] [PATCH 05/14] drm/i915/tc: Wait for IOM/FW PHY
> initialization of legacy TC ports
> 
> During boot-up/system resume, the TC PHY on legacy ports will be initialized by
> the IOM/TCSS firmware regardless of a sink being connected or not (as opposed
> to DP-alt/TBT ports, which the FW only inits once a sink is connected).
> 
> Wait for the above initialization to complete during HW readout, so that
> connecting the PHY later will already see the expected PHY ready state.
> 
> Signed-off-by: Imre Deak <imre.deak at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_tc.c | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_tc.c
> b/drivers/gpu/drm/i915/display/intel_tc.c
> index e8cf3b506fb7f..2116c82831a53 100644
> --- a/drivers/gpu/drm/i915/display/intel_tc.c
> +++ b/drivers/gpu/drm/i915/display/intel_tc.c
> @@ -582,6 +582,15 @@ static bool icl_tc_phy_is_connected(struct
> intel_digital_port *dig_port)
>  	       dig_port->tc_mode == TC_PORT_LEGACY;  }
> 
> +static void tc_phy_wait_for_ready(struct intel_digital_port *dig_port)
> +{
> +	struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
> +
> +	if (wait_for(tc_phy_status_complete(dig_port), 100))
> +		drm_err(&i915->drm, "Port %s: timeout waiting for PHY
> ready\n",

This timeout value is probably based on experimentation as I couldn't find any specs for this. 

Reviewed-by: Mika Kahola <mika.kahola at intel.com>

> +			dig_port->tc_port_name);
> +}
> +
>  static enum tc_port_mode
>  intel_tc_port_get_current_mode(struct intel_digital_port *dig_port)  { @@ -
> 589,6 +598,14 @@ intel_tc_port_get_current_mode(struct intel_digital_port
> *dig_port)
>  	u32 live_status_mask = tc_port_live_status_mask(dig_port);
>  	enum tc_port_mode mode;
> 
> +	/*
> +	 * For legacy ports the IOM firmware initializes the PHY during boot-up
> +	 * and system resume whether or not a sink is connected. Wait here for
> +	 * the initialization to get ready.
> +	 */
> +	if (dig_port->tc_legacy_port)
> +		tc_phy_wait_for_ready(dig_port);
> +
>  	if (!tc_phy_is_owned(dig_port) ||
>  	    drm_WARN_ON(&i915->drm, !tc_phy_status_complete(dig_port)))
>  		return TC_PORT_TBT_ALT;
> --
> 2.37.1