Make PCI CONF2 support a compile time option

It's not used on any board supported by coreboot but has been
detected at run time since ages. No new boards (since 2000?)
are using the CONF2 method, so it is unlikely we ever have to
turn this on for a board.

Change-Id: I17df94a8a77b9338fde10a6b114b44d393776e66
Signed-off-by: Stefan Reinauer <reinauer@google.com>
Reviewed-on: http://review.coreboot.org/758
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

src/arch/x86/Kconfig

@@ -100,4 +100,8 @@ config IOAPIC_INTERRUPTS_ON_APIC_SERIAL_BUS
 	bool
 	default n
 
+config PCI_CONF2
+	bool
+	default n
+
 endmenu

src/arch/x86/lib/Makefile.inc

@@ -1,10 +1,8 @@
 ramstage-y += c_start.S
 ramstage-y += cpu.c
 ramstage-y += pci_ops_conf1.c
-ramstage-y += pci_ops_conf2.c
+ramstage-$(CONFIG_PCI_CONF2) += pci_ops_conf2.c
-
 ramstage-$(CONFIG_MMCONF_SUPPORT) += pci_ops_mmconf.c
-
 ramstage-y += pci_ops_auto.c
 ramstage-y += exception.c
 ramstage-$(CONFIG_IOAPIC) += ioapic.c

src/arch/x86/lib/pci_ops_auto.c

@@ -6,6 +6,7 @@
 #include <device/pci_ids.h>
 #include <device/pci_ops.h>
 
+#if CONFIG_PCI_CONF2
 /*
  * Before we decide to use direct hardware access mechanisms, we try to do some
  * trivial checks to ensure it at least _seems_ to be working -- we just test
@@ -41,7 +42,7 @@ static int pci_sanity_check(const struct pci_bus_operations *o)
 	return 0;
 }
 
-struct pci_bus_operations *pci_bus_fallback_ops = NULL;
+static struct pci_bus_operations *pci_bus_fallback_ops = NULL;
 
 static const struct pci_bus_operations *pci_check_direct(void)
 {
@@ -89,6 +90,12 @@ const struct pci_bus_operations *pci_remember_direct(void)
 		pci_bus_fallback_ops = (struct pci_bus_operations *)pci_check_direct();
 	return pci_bus_fallback_ops;
 }
+#else
+const struct pci_bus_operations *pci_remember_direct(void)
+{
+	return &pci_cf8_conf1;
+}
+#endif
 
 /** Set the method to be used for PCI, type I or type II
  */