drm/i915/pxp: Pxp hw init should be in resume_complete

During suspend flow, i915 currently achors' on the pm_suspend_prepare
callback as the location where we quiesce the entire GPU and perform
all necessary cleanup in order to go into suspend. PXP is also called
during this time to perform the arbitration session teardown (with
the assurance no additional GEM IOCTLs will come after that could
restart the session).

However, if other devices or drivers fail their suspend_prepare, the
system will not go into suspend and i915 will be expected to resume
operation. In this case, we need to re-initialize the PXP hardware
and this really should be done within the pm_resume_complete callback
which is the correct opposing function in the resume sequence to
match pm_suspend_prepare of the suspend sequence.

Because this callback is the last thing at the end of resuming
we expect little to no impact to the rest of the i915 resume sequence
with this change.
Signed-off-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230125082637.118970-7-alan.previn.teres.alexis@intel.com

drivers/gpu/drm/i915/i915_driver.c

@@ -1035,6 +1035,13 @@ static bool suspend_to_idle(struct drm_i915_private *dev_priv)
 	return false;
 }
 
+static void i915_drm_complete(struct drm_device *dev)
+{
+	struct drm_i915_private *i915 = to_i915(dev);
+
+	intel_pxp_resume_complete(i915->pxp);
+}
+
 static int i915_drm_prepare(struct drm_device *dev)
 {
 	struct drm_i915_private *i915 = to_i915(dev);
@@ -1235,8 +1242,6 @@ static int i915_drm_resume(struct drm_device *dev)
 
 	i915_gem_resume(dev_priv);
 
-	intel_pxp_resume(dev_priv->pxp);
-
 	intel_modeset_init_hw(dev_priv);
 	intel_init_clock_gating(dev_priv);
 	intel_hpd_init(dev_priv);
@@ -1428,6 +1433,16 @@ static int i915_pm_resume(struct device *kdev)
 	return i915_drm_resume(&i915->drm);
 }
 
+static void i915_pm_complete(struct device *kdev)
+{
+	struct drm_i915_private *i915 = kdev_to_i915(kdev);
+
+	if (i915->drm.switch_power_state == DRM_SWITCH_POWER_OFF)
+		return;
+
+	i915_drm_complete(&i915->drm);
+}
+
 /* freeze: before creating the hibernation_image */
 static int i915_pm_freeze(struct device *kdev)
 {
@@ -1648,6 +1663,7 @@ const struct dev_pm_ops i915_pm_ops = {
 	.suspend_late = i915_pm_suspend_late,
 	.resume_early = i915_pm_resume_early,
 	.resume = i915_pm_resume,
+	.complete = i915_pm_complete,
 
 	/*
 	 * S4 event handlers

drivers/gpu/drm/i915/pxp/intel_pxp_pm.c

@@ -34,7 +34,7 @@ void intel_pxp_suspend(struct intel_pxp *pxp)
 	}
 }
 
-void intel_pxp_resume(struct intel_pxp *pxp)
+void intel_pxp_resume_complete(struct intel_pxp *pxp)
 {
 	if (!intel_pxp_is_enabled(pxp))
 		return;

drivers/gpu/drm/i915/pxp/intel_pxp_pm.h

@@ -11,7 +11,7 @@ struct intel_pxp;
 #ifdef CONFIG_DRM_I915_PXP
 void intel_pxp_suspend_prepare(struct intel_pxp *pxp);
 void intel_pxp_suspend(struct intel_pxp *pxp);
-void intel_pxp_resume(struct intel_pxp *pxp);
+void intel_pxp_resume_complete(struct intel_pxp *pxp);
 void intel_pxp_runtime_suspend(struct intel_pxp *pxp);
 #else
 static inline void intel_pxp_suspend_prepare(struct intel_pxp *pxp)
@@ -22,7 +22,7 @@ static inline void intel_pxp_suspend(struct intel_pxp *pxp)
 {
 }
 
-static inline void intel_pxp_resume(struct intel_pxp *pxp)
+static inline void intel_pxp_resume_complete(struct intel_pxp *pxp)
 {
 }
 
@@ -32,6 +32,6 @@ static inline void intel_pxp_runtime_suspend(struct intel_pxp *pxp)
 #endif
 static inline void intel_pxp_runtime_resume(struct intel_pxp *pxp)
 {
-	intel_pxp_resume(pxp);
+	intel_pxp_resume_complete(pxp);
 }
 #endif /* __INTEL_PXP_PM_H__ */