[PATCH v1 14/14] xen/arm: Add linux,pci-domain property for hwdom if not available.

[Rahul Singh <rahul.singh@arm.com>]

If the property is not present in the device tree node for host bridge,
XEN while creating the dtb for hwdom will create this property and
assigns the already allocated segment to the host bridge
so that XEN and linux will have the same segment for the host bridges.

Signed-off-by: Rahul Singh <rahul.singh@arm.com>
---
 xen/arch/arm/domain_build.c        | 18 ++++++++++++++++++
 xen/arch/arm/pci/pci-host-common.c | 21 +++++++++++++++++++++
 xen/include/asm-arm/pci.h          |  3 +++
 3 files changed, 42 insertions(+)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 6c86d52781..e0cf2ff19d 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -581,6 +581,24 @@ static int __init write_properties(struct domain *d, struct kernel_info *kinfo,
             return res;
     }
 
+#ifdef CONFIG_HAS_PCI
+    if ( dt_device_type_is_equal(node, "pci") )
+    {
+        if ( !dt_find_property(node, "linux,pci-domain", NULL) )
+        {
+            uint16_t segment;
+
+            res = pci_get_host_bridge_segment(node, &segment);
+            if ( res < 0 )
+                return res;
+
+            res = fdt_property_cell(kinfo->fdt, "linux,pci-domain", segment);
+            if ( res )
+                return res;
+        }
+    }
+#endif
+
     /*
      * Override the property "status" to disable the device when it's
      * marked for passthrough.
diff --git a/xen/arch/arm/pci/pci-host-common.c b/xen/arch/arm/pci/pci-host-common.c
index 62715b4676..5e34252deb 100644
--- a/xen/arch/arm/pci/pci-host-common.c
+++ b/xen/arch/arm/pci/pci-host-common.c
@@ -280,6 +280,27 @@ struct pci_host_bridge *pci_find_host_bridge(uint16_t segment, uint8_t bus)
 
     return NULL;
 }
+
+/*
+ * This function will lookup an hostbridge based on config space address.
+ */
+int pci_get_host_bridge_segment(const struct dt_device_node *node,
+                                uint16_t *segment)
+{
+    struct pci_host_bridge *bridge;
+
+    list_for_each_entry( bridge, &pci_host_bridges, node )
+    {
+        if ( bridge->dt_node != node )
+            continue;
+
+        *segment = bridge->segment;
+        return 0;
+    }
+
+    return -EINVAL;
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/include/asm-arm/pci.h b/xen/include/asm-arm/pci.h
index c58152de80..2d4610a23a 100644
--- a/xen/include/asm-arm/pci.h
+++ b/xen/include/asm-arm/pci.h
@@ -96,6 +96,9 @@ void __iomem *pci_ecam_map_bus(struct pci_host_bridge *bridge,
                                uint32_t sbdf, uint32_t where);
 
 struct pci_host_bridge *pci_find_host_bridge(uint16_t segment, uint8_t bus);
+int pci_get_host_bridge_segment(const struct dt_device_node *node,
+                                uint16_t *segment);
+
 #else   /*!CONFIG_HAS_PCI*/
 
 struct arch_pci_dev { };
-- 
2.17.1