dm: pci: Allow delaying auto-config until after relocation

At present PCI auto-configuration happens in U-Boot both before and after
relocation. This is a waste of time and may mess up static addresses used
in board_init_f(). Adjust the code to supporting doing auto-configuration
once, after relocation, under control of a device-tree property.

This is needed for Apollo Lake for debugging the silicon-init code. Once
the UART is moved to a different MMIO address the debug UART does not work
and any debug output in Apollo Lake's arch_fsp_init_r() causes a hang.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

include/pci.h

@@ -571,15 +571,22 @@ extern void pci_cfgfunc_config_device(struct pci_controller* hose, pci_dev_t dev
 
 #define INDIRECT_TYPE_NO_PCIE_LINK	1
 
-/*
+/**
  * Structure of a PCI controller (host bridge)
  *
  * With driver model this is dev_get_uclass_priv(bus)
+ *
+ * @skip_auto_config_until_reloc: true to avoid auto-config until U-Boot has
+ *	relocated. Normally if PCI is used before relocation, this happens
+ *	before relocation also. Some platforms set up static configuration in
+ *	TPL/SPL to reduce code size and boot time, since these phases only know
+ *	about a small subset of PCI devices. This is normally false.
  */
 struct pci_controller {
 #ifdef CONFIG_DM_PCI
 	struct udevice *bus;
 	struct udevice *ctlr;
+	bool skip_auto_config_until_reloc;
 #else
 	struct pci_controller *next;
 #endif