dm: pci: Move pci_get_devfn() into a common file

Early in boot it is necessary to decode the PCI device/function values for
particular peripherals in the device tree or of-platdata. This is needed
in TPL where CONFIG_PCI is not defined.

To handle this, move pci_get_devfn() into a file that is built even when
CONFIG_PCI is not defined.

Also add a function for use by of-platdata, to convert a reg property to
a pci_dev_t.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/include/dm/pci.h b/include/dm/pci.h
new file mode 100644
index 0000000..10f9fd9
--- /dev/null
+++ b/include/dm/pci.h
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (c) 2019 Google, Inc
+ */
+
+#ifndef __DM_PCI_H
+#define __DM_PCI_H
+
+struct udevice;
+
+/**
+ * pci_get_devfn() - Extract the devfn from fdt_pci_addr of the device
+ *
+ * Get devfn from fdt_pci_addr of the specified device
+ *
+ * This returns an int to avoid a dependency on pci.h
+ *
+ * @dev:	PCI device
+ * @return devfn in bits 15...8 if found (pci_dev_t format), or -ENODEV if not
+ *	found
+ */
+int pci_get_devfn(struct udevice *dev);
+
+/**
+ * pci_ofplat_get_devfn() - Get the PCI dev/fn from of-platdata
+ *
+ * This function is used to obtain a PCI device/function from of-platdata
+ * register data. In this case the first cell of the 'reg' property contains
+ * the required information.
+ *
+ * This returns an int to avoid a dependency on pci.h
+ *
+ * @reg: reg value from dt-platdata.c array (first member). This is not a
+ *	pointer type, since the caller may use fdt32_t or fdt64_t depending on
+ *	the address sizes.
+ * @return device/function for that device (pci_dev_t format)
+ */
+static inline int pci_ofplat_get_devfn(u32 reg)
+{
+	return reg & 0xff00;
+}
+
+#endif