[PATCH v2 04/11] ACPI/IORT: Check ATS capability in root complex node

[Jean-Philippe Brucker <jean-philippe@linaro.org>]

When initializing a PCI root bridge, copy its "ATS supported" attribute
into the root bridge.

Acked-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
 drivers/acpi/arm64/iort.c | 27 +++++++++++++++++++++++++++
 drivers/acpi/pci_root.c   |  3 +++
 include/linux/acpi_iort.h |  8 ++++++++
 3 files changed, 38 insertions(+)

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index ed3d2d1a7ae9..d99d7f5b51e1 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -1633,6 +1633,33 @@ static void __init iort_enable_acs(struct acpi_iort_node *iort_node)
 		}
 	}
 }
+
+static acpi_status iort_match_host_bridge_callback(struct acpi_iort_node *node,
+						   void *context)
+{
+	struct acpi_iort_root_complex *pci_rc;
+	struct pci_host_bridge *host_bridge = context;
+
+	pci_rc = (struct acpi_iort_root_complex *)node->node_data;
+
+	return pci_domain_nr(host_bridge->bus) == pci_rc->pci_segment_number ?
+		AE_OK : AE_NOT_FOUND;
+}
+
+void iort_pci_host_bridge_setup(struct pci_host_bridge *host_bridge)
+{
+	struct acpi_iort_node *node;
+	struct acpi_iort_root_complex *pci_rc;
+
+	node = iort_scan_node(ACPI_IORT_NODE_PCI_ROOT_COMPLEX,
+			      iort_match_host_bridge_callback, host_bridge);
+	if (!node)
+		return;
+
+	pci_rc = (struct acpi_iort_root_complex *)node->node_data;
+	host_bridge->ats_supported = !!(pci_rc->ats_attribute &
+					ACPI_IORT_ATS_SUPPORTED);
+}
 #else
 static inline void iort_enable_acs(struct acpi_iort_node *iort_node) { }
 #endif
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index d1e666ef3fcc..eb2fb8f17c0b 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -6,6 +6,7 @@
  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
  */
 
+#include <linux/acpi_iort.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/init.h>
@@ -917,6 +918,8 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
 	if (!(root->osc_control_set & OSC_PCI_EXPRESS_LTR_CONTROL))
 		host_bridge->native_ltr = 0;
 
+	iort_pci_host_bridge_setup(host_bridge);
+
 	/*
 	 * Evaluate the "PCI Boot Configuration" _DSM Function.  If it
 	 * exists and returns 0, we must preserve any PCI resource
diff --git a/include/linux/acpi_iort.h b/include/linux/acpi_iort.h
index 8e7e2ec37f1b..7b06871cc3aa 100644
--- a/include/linux/acpi_iort.h
+++ b/include/linux/acpi_iort.h
@@ -10,6 +10,7 @@
 #include <linux/acpi.h>
 #include <linux/fwnode.h>
 #include <linux/irqdomain.h>
+#include <linux/pci.h>
 
 #define IORT_IRQ_MASK(irq)		(irq & 0xffffffffULL)
 #define IORT_IRQ_TRIGGER_MASK(irq)	((irq >> 32) & 0xffffffffULL)
@@ -55,4 +56,11 @@ int iort_iommu_msi_get_resv_regions(struct device *dev, struct list_head *head)
 { return 0; }
 #endif
 
+#if defined(CONFIG_ACPI_IORT) && defined(CONFIG_PCI)
+void iort_pci_host_bridge_setup(struct pci_host_bridge *host_bridge);
+#else
+static inline
+void iort_pci_host_bridge_setup(struct pci_host_bridge *host_bridge) { }
+#endif
+
 #endif /* __ACPI_IORT_H__ */
-- 
2.25.1