[PATCH v4 02/11] PCI/ACPI: Per root port allow one Aux power limit request

[Badal Nilawar]

For given root port allow one Aux power limit request.

Cc: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
Cc: Anshuman Gupta <anshuman.gupta at intel.com>
Signed-off-by: Badal Nilawar <badal.nilawar at intel.com>
---
 drivers/acpi/scan.c     |  1 +
 drivers/pci/pci-acpi.c  | 25 ++++++++++++++++++++++++-
 include/acpi/acpi_bus.h |  2 ++
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index fb1fe9f3b1a3..9ae7be9db01a 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -745,6 +745,7 @@ int acpi_device_add(struct acpi_device *device)
 	INIT_LIST_HEAD(&device->physical_node_list);
 	INIT_LIST_HEAD(&device->del_list);
 	mutex_init(&device->physical_node_lock);
+	mutex_init(&device->power.aux_pwr_lock);
 
 	mutex_lock(&acpi_device_lock);
 
diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index 87f30910a5f1..d33efba4ca94 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -1451,6 +1451,7 @@ int pci_acpi_request_d3cold_aux_power(struct pci_dev *dev, u32 requested_power,
 	union acpi_object *out_obj;
 	acpi_handle handle;
 	int result, ret = -EINVAL;
+	struct acpi_device *adev;
 
 	if (!dev || !retry_interval)
 		return -EINVAL;
@@ -1464,11 +1465,27 @@ int pci_acpi_request_d3cold_aux_power(struct pci_dev *dev, u32 requested_power,
 		return -ENODEV;
 	}
 
+	adev = ACPI_COMPANION(&dev->dev);
+	if (!adev)
+		return -EINVAL;
+
+	mutex_lock(&adev->power.aux_pwr_lock);
+
+	/* Check if aux power already granted */
+	if (adev->power.aux_power_limit) {
+		pci_info(dev, "D3cold Aux Power request already granted: %u mW\n",
+			 adev->power.aux_power_limit);
+		mutex_unlock(&adev->power.aux_pwr_lock);
+		return -EPERM;
+	}
+
 	out_obj = acpi_evaluate_dsm_typed(handle, &pci_acpi_dsm_guid, 4,
 					  DSM_PCI_D3COLD_AUX_POWER_LIMIT,
 					  &in_obj, ACPI_TYPE_INTEGER);
-	if (!out_obj)
+	if (!out_obj) {
+		mutex_unlock(&adev->power.aux_pwr_lock);
 		return -EINVAL;
+	}
 
 	result = out_obj->integer.value;
 	if (retry_interval)
@@ -1478,14 +1495,17 @@ int pci_acpi_request_d3cold_aux_power(struct pci_dev *dev, u32 requested_power,
 	case 0x0:
 		pci_dbg(dev, "D3cold Aux Power %u mW request denied\n",
 			requested_power);
+		adev->power.aux_power_limit = 0;
 		break;
 	case 0x1:
 		pci_info(dev, "D3cold Aux Power request granted: %u mW\n",
 			 requested_power);
+		adev->power.aux_power_limit = requested_power;
 		ret = 0;
 		break;
 	case 0x2:
 		pci_info(dev, "D3cold Aux Power: Main power won't be removed\n");
+		adev->power.aux_power_limit = 0;
 		ret = -EBUSY;
 		break;
 	default:
@@ -1500,9 +1520,12 @@ int pci_acpi_request_d3cold_aux_power(struct pci_dev *dev, u32 requested_power,
 			pci_err(dev, "D3cold Aux Power: Reserved or unsupported response: 0x%x\n",
 				result);
 		}
+		adev->power.aux_power_limit = 0;
 		break;
 	}
 
+	mutex_unlock(&adev->power.aux_pwr_lock);
+
 	ACPI_FREE(out_obj);
 	return ret;
 }
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index aad1a95e6863..c4ce3d84be00 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -294,6 +294,8 @@ struct acpi_device_power {
 	struct acpi_device_power_flags flags;
 	struct acpi_device_power_state states[ACPI_D_STATE_COUNT];	/* Power states (D0-D3Cold) */
 	u8 state_for_enumeration; /* Deepest power state for enumeration */
+	u32 aux_power_limit;		/* aux power limit granted by bios */
+	struct mutex aux_pwr_lock;	/* prevent concurrent aux power limit requests */
 };
 
 struct acpi_dep_data {
-- 
2.34.1