xen/arm: Add new device type for PCI

Add new device type (DEV_PCI) to distinguish PCI devices from platform
DT devices, so some drivers, like IOMMU, can handle PCI devices
differently.

Also add a helper which is when given a struct device returns the
corresponding struct pci_dev which this device is a part of.

Because of the header cross-dependencies, e.g. we need both
struct pci_dev and struct arch_pci_dev at the same time, this cannot be
done with an inline.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@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>

xen/arch/arm/pci/pci.c

@@ -27,6 +27,13 @@ int arch_pci_clean_pirqs(struct domain *d)
     return 0;
 }
 
+struct pci_dev *dev_to_pci(struct device *dev)
+{
+    ASSERT(dev->type == DEV_PCI);
+
+    return container_of(dev, struct pci_dev, arch.dev);
+}
+
 static int __init dt_pci_init(void)
 {
     struct dt_device_node *np;

xen/include/asm-arm/device.h

@@ -4,6 +4,7 @@
 enum device_type
 {
     DEV_DT,
+    DEV_PCI,
 };
 
 struct dev_archdata {
@@ -25,8 +26,7 @@ typedef struct device device_t;
 
 #include <xen/device_tree.h>
 
-/* TODO: Correctly implement dev_is_pci when PCI is supported on ARM */
-#define dev_is_pci(dev) ((void)(dev), 0)
+#define dev_is_pci(dev) ((dev)->type == DEV_PCI)
 #define dev_is_dt(dev)  ((dev)->type == DEV_DT)
 
 enum device_class

xen/include/asm-arm/pci.h

@@ -26,6 +26,13 @@ struct arch_pci_dev {
     struct device dev;
 };
 
+/*
+ * Because of the header cross-dependencies, e.g. we need both
+ * struct pci_dev and struct arch_pci_dev at the same time, this cannot be
+ * done with an inline here. Macro can be implemented, but looks scary.
+ */
+struct pci_dev *dev_to_pci(struct device *dev);
+
 /*
  * struct to hold the mappings of a config space window. This
  * is expected to be used as sysdata for PCI controllers that