intel/i5000: Use MMCONF_SUPPORT_DEFAULT

Change all PCI configuration accesses to MMIO on two boards
with i5000 chipset. To enable MMIO style access, add explicit
PCI IO config write in the bootblock.

Change-Id: I26f1c2da5ae98aeeda78bdcae0fb1e8c711a3586
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/3601
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

src/mainboard/asus/dsbf/romstage.c

@@ -129,10 +129,6 @@ void main(unsigned long bist)
 
 	enable_smbus();
 
-	/* setup PCIe MMCONF base address */
-	pci_write_config32(PCI_DEV(0, 16, 0), 0x64,
-			   CONFIG_MMCONF_BASE_ADDRESS >> 16);
-
         smbus_write_byte(0x6f, 0x00, 0x63);
         smbus_write_byte(0x6f, 0x01, 0x04);
         smbus_write_byte(0x6f, 0x02, 0x53);

src/mainboard/supermicro/x7db8/romstage.c

@@ -128,10 +128,6 @@ void main(unsigned long bist)
 
 	enable_smbus();
 
-	/* setup PCIe MMCONF base address */
-	pci_write_config32(PCI_DEV(0, 16, 0), 0x64,
-			   CONFIG_MMCONF_BASE_ADDRESS >> 16);
-
 	outb(0x07, 0x11b8);
 
 	/* These are smbus write captured with serialice. They

src/northbridge/intel/i5000/Kconfig

@@ -20,9 +20,17 @@
 config NORTHBRIDGE_INTEL_I5000
 	bool
 	select MMCONF_SUPPORT
+	select MMCONF_SUPPORT_DEFAULT
 	select HAVE_DEBUG_RAM_SETUP
 
+if NORTHBRIDGE_INTEL_I5000
+
 config NORTHBRIDGE_INTEL_I5000_RAM_CHECK
 	bool
 	prompt "Run ramcheck after RAM initialization"
-	depends on NORTHBRIDGE_INTEL_I5000
+
+config BOOTBLOCK_NORTHBRIDGE_INIT
+	string
+	default "northbridge/intel/i5000/bootblock.c"
+
+endif

src/northbridge/intel/i5000/bootblock.c

@@ -0,0 +1,21 @@
+#include <arch/io.h>
+
+static void bootblock_northbridge_init(void)
+{
+	/*
+	 * The "io" variant of the config access is explicitly used to
+	 * setup the PCIEXBAR because CONFIG_MMCONF_SUPPORT_DEFAULT is set to
+	 * to true. That way all subsequent non-explicit config accesses use
+	 * MCFG. This code also assumes that bootblock_northbridge_init() is
+	 * the first thing called in the non-asm boot block code. The final
+	 * assumption is that no assembly code is using the
+	 * CONFIG_MMCONF_SUPPORT_DEFAULT option to do PCI config acceses.
+	 *
+	 * The PCIEXBAR is assumed to live in the memory mapped IO space under
+	 * 4GiB.
+	 */
+
+	/* setup PCIe MMCONF base address */
+	pci_io_write_config32(PCI_DEV(0, 16, 0), 0x64,
+			   CONFIG_MMCONF_BASE_ADDRESS >> 16);
+}