drm/i915/dg1: Wait for pcode/uncore handshake at startup

DG1 does some additional pcode/uncore handshaking at
boot time; this handshaking must complete before various other pcode
commands are effective and before general work is submitted to the GPU.
We need to poll a new pcode mailbox during startup until it reports that
this handshaking is complete.

The bspec doesn't give guidance on how long we may need to wait for this
handshaking to complete.  For now, let's just set a really long timeout;
if we still don't get a completion status by the end of that timeout,
we'll just continue on and hope for the best.

v2 (Lucas): Rename macros to make clear the relation between command and
   result (requested by José)

Bspec: 52065
Cc: Clinton Taylor <Clinton.A.Taylor@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201001063917.3133475-2-lucas.demarchi@intel.com

1 files changed, 15 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_sideband.c b/drivers/gpu/drm/i915/intel_sideband.c
index 5b3279262123..02ebf5a04a9b 100644
--- a/drivers/gpu/drm/i915/intel_sideband.c
+++ b/drivers/gpu/drm/i915/intel_sideband.c
@@ -555,3 +555,18 @@ out:
 	return ret ? ret : status;
 #undef COND
 }
+
+void intel_pcode_init(struct drm_i915_private *i915)
+{
+	int ret;
+
+	if (!IS_DGFX(i915))
+		return;
+
+	ret = skl_pcode_request(i915, DG1_PCODE_STATUS,
+				DG1_UNCORE_GET_INIT_STATUS,
+				DG1_UNCORE_INIT_STATUS_COMPLETE,
+				DG1_UNCORE_INIT_STATUS_COMPLETE, 50);
+	if (ret)
+		drm_err(&i915->drm, "Pcode did not report uncore initialization completion!\n");
+}