northbridge/intel/x4x: Intel 4-series northbridge support

Boots to console on Gigabyte GA-G41M-ES2L

Ram initialization *not* included in this patch
VGA native init works on analog connector

Change-Id: I5262f73fd03d5e5c12e9f11d027bdfbbf0ddde82
Signed-off-by: Damien Zammit <damien@zamaudio.com>
Reviewed-on: https://review.coreboot.org/11305
Tested-by: build bot (Jenkins)
Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>

src/northbridge/intel/x4x/bootblock.c

@@ -0,0 +1,32 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2015  Damien Zammit <damien@zamaudio.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <arch/io.h>
+
+#define D0F0_PCIEXBAR_LO 0x60
+#define TPMBASE 0xfed40000
+#define TPM32(x) *((volatile u32 *)(TPMBASE + x))
+
+static void bootblock_northbridge_init(void)
+{
+	uint32_t reg32;
+
+	/* Disable LaGrande Technology (LT) */
+	reg32 = TPM32(0);
+
+	reg32 = CONFIG_MMCONF_BASE_ADDRESS | 16 | 1;
+	pci_io_write_config32(PCI_DEV(0,0,0), D0F0_PCIEXBAR_LO, reg32);
+}