pci_init(..) will be called during xen startup to initialize and probe
the PCI host-bridge driver.

Signed-off-by: Rahul Singh <rahul.singh@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>
---
Change in v4:
- Added Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>
- Added Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Change in v3:
- Some nit for device_init(..) return logic
- Remove inline from acpi_pci_init(..)
- Modify return value for apci_pci_init(..) to return -EOPNOTSUPP
Change in v2:
- ACPI init function to return int
- pci_segments_init() called before dt/acpi init
---
---
 xen/arch/arm/pci/pci.c       | 51 ++++++++++++++++++++++++++++++++++++
 xen/include/asm-arm/device.h |  1 +
 2 files changed, 52 insertions(+)

diff --git a/xen/arch/arm/pci/pci.c b/xen/arch/arm/pci/pci.c
index a7a7bc3213..e359bab9ea 100644
--- a/xen/arch/arm/pci/pci.c
+++ b/xen/arch/arm/pci/pci.c
@@ -12,6 +12,10 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <xen/acpi.h>
+#include <xen/device_tree.h>
+#include <xen/errno.h>
+#include <xen/init.h>
 #include <xen/pci.h>
 
 /*
@@ -22,6 +26,53 @@ int arch_pci_clean_pirqs(struct domain *d)
     return 0;
 }
 
+static int __init dt_pci_init(void)
+{
+    struct dt_device_node *np;
+    int rc;
+
+    dt_for_each_device_node(dt_host, np)
+    {
+        rc = device_init(np, DEVICE_PCI, NULL);
+        /*
+         * Ignore the following error codes:
+         *   - EBADF: Indicate the current device is not a pci device.
+         *   - ENODEV: The pci device is not present or cannot be used by
+         *     Xen.
+         */
+        if( !rc || rc == -EBADF || rc == -ENODEV )
+            continue;
+
+        return rc;
+    }
+
+    return 0;
+}
+
+#ifdef CONFIG_ACPI
+static int __init acpi_pci_init(void)
+{
+    printk(XENLOG_ERR "ACPI pci init not supported \n");
+    return -EOPNOTSUPP;
+}
+#else
+static int __init acpi_pci_init(void)
+{
+    return -EINVAL;
+}
+#endif
+
+static int __init pci_init(void)
+{
+    pci_segments_init();
+
+    if ( acpi_disabled )
+        return dt_pci_init();
+    else
+        return acpi_pci_init();
+}
+__initcall(pci_init);
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/include/asm-arm/device.h b/xen/include/asm-arm/device.h
index ee7cff2d44..5ecd5e7bd1 100644
--- a/xen/include/asm-arm/device.h
+++ b/xen/include/asm-arm/device.h
@@ -34,6 +34,7 @@ enum device_class
     DEVICE_SERIAL,
     DEVICE_IOMMU,
     DEVICE_GIC,
+    DEVICE_PCI,
     /* Use for error */
     DEVICE_UNKNOWN,
 };
-- 
2.25.1