drm/i915/tc/icl: Implement TC cold sequences

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
Closes: 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>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200414194956.164323-4-jose.souza@intel.com

1 files changed, 24 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/display/intel_display_power.c b/drivers/gpu/drm/i915/display/intel_display_power.c
index 606a1659021b..c4043d665645 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);