[PATCH 08/12] drm/xe: Add PCIe ACPI Aux Power notifier

[Anshuman Gupta]

Register PCIe ACPI notifier block and mark vrsr_capable
false in the notifier callback. This will ensure that
BMG GPU does not explode if any other PCIe child device
(under same Root Port) aux power request returns
with No main power removal.

Signed-off-by: Anshuman Gupta <anshuman.gupta at intel.com>
---
 drivers/gpu/drm/xe/xe_device_types.h |  3 ++
 drivers/gpu/drm/xe/xe_pm.c           | 41 ++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+)

diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
index fd9dea207580..9aacd5af7d0f 100644
--- a/drivers/gpu/drm/xe/xe_device_types.h
+++ b/drivers/gpu/drm/xe/xe_device_types.h
@@ -517,6 +517,9 @@ struct xe_device {
 		struct mutex lock;
 	} d3cold;
 
+	/** @nb: PCI ACPI Aux power notifier */
+	struct notifier_block nb;
+
 	/** @pmt: Support the PMT driver callback interface */
 	struct {
 		/** @pmt.lock: protect access for telemetry data */
diff --git a/drivers/gpu/drm/xe/xe_pm.c b/drivers/gpu/drm/xe/xe_pm.c
index 364b937e0ded..ea93923d6671 100644
--- a/drivers/gpu/drm/xe/xe_pm.c
+++ b/drivers/gpu/drm/xe/xe_pm.c
@@ -87,6 +87,41 @@ static struct lockdep_map xe_pm_runtime_nod3cold_map = {
 };
 #endif
 
+static int aux_pwr_notifier(struct notifier_block *nb,
+			    unsigned long val, void *data)
+{
+	struct pci_dev *root_pdev = data;
+	struct pci_dev *pdev;
+	struct xe_device *xe;
+
+	xe = container_of(nb, struct xe_device, nb);
+
+	pdev = pcie_find_root_port(to_pci_dev(xe->drm.dev));
+	if (!pdev)
+		return -EINVAL;
+
+	if (root_pdev != pdev)
+		return 0;
+
+	xe_pm_runtime_get(xe);
+
+	if (val == ACPI_NO_MAIN_PW_REMOVAL) {
+		drm_err(&xe->drm, "PCIe core blocked the removal of Main Supply\n");
+		xe->d3cold.vrsr_capable = false;
+	}
+
+	xe_pm_runtime_put(xe);
+
+	return 0;
+}
+
+static void xe_pm_vrsr_fini(void *arg)
+{
+	struct xe_device *xe = arg;
+
+	pci_acpi_unregister_aux_power_notifier(&xe->nb);
+}
+
 /**
  * xe_rpm_reclaim_safe() - Whether runtime resume can be done from reclaim context
  * @xe: The xe device.
@@ -295,6 +330,12 @@ static int pci_acpi_aux_power_setup(struct xe_device *xe)
 		return ret;
 
 	ret = pci_acpi_add_perst_assertion_delay(root_pdev, perst_delay);
+	if (ret)
+		return ret;
+
+	xe->nb.notifier_call = aux_pwr_notifier;
+	pci_acpi_register_aux_power_notifier(&xe->nb);
+	devm_add_action_or_reset(xe->drm.dev, xe_pm_vrsr_fini, xe);
 
 	return ret;
 }
-- 
2.43.0