[PATCH 4/7] ACPI/IORT: Check ATS capability in root complex nodes

[Jean-Philippe Brucker]

Root complex node in IORT has a bit telling whether it supports ATS or
not. Store this bit in the IOMMU fwspec when setting up a device, so it
can be accessed later by an IOMMU driver.

Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker at arm.com>
---
 drivers/acpi/arm64/iort.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index c5fecf97ee2f..e7d2d156d78f 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -720,6 +720,14 @@ void iort_set_dma_mask(struct device *dev)
 		dev->dma_mask = &dev->coherent_dma_mask;
 }
 
+static bool iort_pci_rc_supports_ats(struct acpi_iort_node *node)
+{
+	struct acpi_iort_root_complex *pci_rc;
+
+	pci_rc = (struct acpi_iort_root_complex *)node->node_data;
+	return pci_rc->ats_attribute & ACPI_IORT_ATS_SUPPORTED;
+}
+
 /**
  * iort_iommu_configure - Set-up IOMMU configuration for a device.
  *
@@ -752,6 +760,8 @@ const struct iommu_ops *iort_iommu_configure(struct device *dev)
 
 		ops = iort_iommu_xlate(dev, parent, streamid);
 
+		if (!IS_ERR_OR_NULL(ops) && iort_pci_rc_supports_ats(node))
+			dev->iommu_fwspec->flags |= IOMMU_FWSPEC_PCI_RC_SUPPORTS_ATS;
 	} else {
 		int i = 0;
 
-- 
2.12.1