[PATCH v5 02/10] xen/arm: Introduce pci_find_host_bridge_node helper

[Oleksandr Andrushchenko <andr2000@gmail.com>]

From: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>

Get host bridge node given a PCI device attached to it.

This helper will be re-used for adding PCI devices by the subsequent
patches.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Rahul Singh <rahul.singh@arm.com>
Tested-by: Rahul Singh <rahul.singh@arm.com>
---
Since v2:
 - !! dropped Stefano's r-b because of the changes
 - s/PRI_pci/%pp after rebase onto Arm series
---
 xen/arch/arm/pci/pci-host-common.c | 16 ++++++++++++++++
 xen/include/asm-arm/pci.h          |  1 +
 2 files changed, 17 insertions(+)

diff --git a/xen/arch/arm/pci/pci-host-common.c b/xen/arch/arm/pci/pci-host-common.c
index 593beeb48ce4..592c01aae5bb 100644
--- a/xen/arch/arm/pci/pci-host-common.c
+++ b/xen/arch/arm/pci/pci-host-common.c
@@ -276,6 +276,22 @@ int pci_get_host_bridge_segment(const struct dt_device_node *node,
     return -EINVAL;
 }
 
+/*
+ * Get host bridge node given a device attached to it.
+ */
+struct dt_device_node *pci_find_host_bridge_node(struct device *dev)
+{
+    struct pci_host_bridge *bridge;
+    struct pci_dev *pdev = dev_to_pci(dev);
+
+    bridge = pci_find_host_bridge(pdev->seg, pdev->bus);
+    if ( unlikely(!bridge) )
+    {
+        printk(XENLOG_ERR "Unable to find PCI bridge for %pp\n", &pdev->sbdf);
+        return NULL;
+    }
+    return bridge->dt_node;
+}
 /*
  * Local variables:
  * mode: C
diff --git a/xen/include/asm-arm/pci.h b/xen/include/asm-arm/pci.h
index 7a91ebbdaf0c..9aa8eca53175 100644
--- a/xen/include/asm-arm/pci.h
+++ b/xen/include/asm-arm/pci.h
@@ -99,6 +99,7 @@ void __iomem *pci_ecam_map_bus(struct pci_host_bridge *bridge,
 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);
+struct dt_device_node *pci_find_host_bridge_node(struct device *dev);
 
 static always_inline bool is_pci_passthrough_enabled(void)
 {
-- 
2.25.1