[PATCH v4 10/15] iommu/vt-d: Probe DMA-capable ACPI name space devices

[Lu Baolu <baolu.lu@linux.intel.com>]

Some platforms may support ACPI name-space enumerated devices
that are capable of generating DMA requests. Platforms which
support DMA remapping explicitly declares any such DMA-capable
ACPI name-space devices in the platform through ACPI Name-space
Device Declaration (ANDD) structure and enumerate them through
the Device Scope of the appropriate remapping hardware unit.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel-iommu.c | 45 +++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index b7f5a6390be6..7f9cf9188f5f 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4816,6 +4816,48 @@ static int __init platform_optin_force_iommu(void)
 	return 1;
 }
 
+static int __init probe_acpi_namespace_devices(void)
+{
+	struct dmar_drhd_unit *drhd;
+	struct intel_iommu *iommu;
+	struct device *dev;
+	int i, ret = 0;
+
+	for_each_active_iommu(iommu, drhd) {
+		for_each_active_dev_scope(drhd->devices,
+					  drhd->devices_cnt, i, dev) {
+			struct acpi_device_physical_node *pn;
+			struct iommu_group *group;
+			struct acpi_device *adev;
+
+			if (dev->bus != &acpi_bus_type)
+				continue;
+
+			adev = to_acpi_device(dev);
+			mutex_lock(&adev->physical_node_lock);
+			list_for_each_entry(pn,
+					    &adev->physical_node_list, node) {
+				group = iommu_group_get(pn->dev);
+				if (group) {
+					iommu_group_put(group);
+					continue;
+				}
+
+				pn->dev->bus->iommu_ops = &intel_iommu_ops;
+				ret = iommu_probe_device(pn->dev);
+				if (ret)
+					break;
+			}
+			mutex_unlock(&adev->physical_node_lock);
+
+			if (ret)
+				return ret;
+		}
+	}
+
+	return 0;
+}
+
 int __init intel_iommu_init(void)
 {
 	int ret = -ENODEV;
@@ -4928,6 +4970,9 @@ int __init intel_iommu_init(void)
 	cpuhp_setup_state(CPUHP_IOMMU_INTEL_DEAD, "iommu/intel:dead", NULL,
 			  intel_iommu_cpu_dead);
 
+	if (probe_acpi_namespace_devices())
+		pr_warn("ACPI name space devices didn't probe correctly\n");
+
 	/* Finally, we enable the DMA remapping hardware. */
 	for_each_iommu(iommu, drhd) {
 		if (!translation_pre_enabled(iommu))
-- 
2.17.1