1 files changed, 58 insertions, 8 deletions

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index daf9fc8329e6..407a3760e8de 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -39,7 +39,7 @@ static const char *dummy_hid = "device";
 
 static LIST_HEAD(acpi_dep_list);
 static DEFINE_MUTEX(acpi_dep_list_lock);
-static LIST_HEAD(acpi_bus_id_list);
+LIST_HEAD(acpi_bus_id_list);
 static DEFINE_MUTEX(acpi_scan_lock);
 static LIST_HEAD(acpi_scan_handlers_list);
 DEFINE_MUTEX(acpi_device_lock);
@@ -52,12 +52,6 @@ struct acpi_dep_data {
 	acpi_handle slave;
 };
 
-struct acpi_device_bus_id{
-	char bus_id[15];
-	unsigned int instance_no;
-	struct list_head node;
-};
-
 void acpi_scan_lock_acquire(void)
 {
 	mutex_lock(&acpi_scan_lock);
@@ -471,10 +465,24 @@ static void acpi_device_release(struct device *dev)
 
 static void acpi_device_del(struct acpi_device *device)
 {
+	struct acpi_device_bus_id *acpi_device_bus_id;
+
 	mutex_lock(&acpi_device_lock);
 	if (device->parent)
 		list_del(&device->node);
 
+	list_for_each_entry(acpi_device_bus_id, &acpi_bus_id_list, node)
+		if (!strcmp(acpi_device_bus_id->bus_id,
+			    acpi_device_hid(device))) {
+			if (acpi_device_bus_id->instance_no > 0)
+				acpi_device_bus_id->instance_no--;
+			else {
+				list_del(&acpi_device_bus_id->node);
+				kfree(acpi_device_bus_id);
+			}
+			break;
+		}
+
 	list_del(&device->wakeup_list);
 	mutex_unlock(&acpi_device_lock);
 
@@ -1308,6 +1316,48 @@ void acpi_free_pnp_ids(struct acpi_device_pnp *pnp)
 	kfree(pnp->unique_id);
 }
 
+/**
+ * acpi_dma_supported - Check DMA support for the specified device.
+ * @adev: The pointer to acpi device
+ *
+ * Return false if DMA is not supported. Otherwise, return true
+ */
+bool acpi_dma_supported(struct acpi_device *adev)
+{
+	if (!adev)
+		return false;
+
+	if (adev->flags.cca_seen)
+		return true;
+
+	/*
+	* Per ACPI 6.0 sec 6.2.17, assume devices can do cache-coherent
+	* DMA on "Intel platforms".  Presumably that includes all x86 and
+	* ia64, and other arches will set CONFIG_ACPI_CCA_REQUIRED=y.
+	*/
+	if (!IS_ENABLED(CONFIG_ACPI_CCA_REQUIRED))
+		return true;
+
+	return false;
+}
+
+/**
+ * acpi_get_dma_attr - Check the supported DMA attr for the specified device.
+ * @adev: The pointer to acpi device
+ *
+ * Return enum dev_dma_attr.
+ */
+enum dev_dma_attr acpi_get_dma_attr(struct acpi_device *adev)
+{
+	if (!acpi_dma_supported(adev))
+		return DEV_DMA_NOT_SUPPORTED;
+
+	if (adev->flags.coherent_dma)
+		return DEV_DMA_COHERENT;
+	else
+		return DEV_DMA_NON_COHERENT;
+}
+
 static void acpi_init_coherency(struct acpi_device *adev)
 {
 	unsigned long long cca = 0;
@@ -1419,7 +1469,7 @@ static int acpi_bus_type_and_status(acpi_handle handle, int *type,
 		*type = ACPI_BUS_TYPE_DEVICE;
 		status = acpi_bus_get_status_handle(handle, sta);
 		if (ACPI_FAILURE(status))
-			return -ENODEV;
+			*sta = 0;
 		break;
 	case ACPI_TYPE_PROCESSOR:
 		*type = ACPI_BUS_TYPE_PROCESSOR;