nb/intel/sandybridge: Define and use MMCONF_BUS_NUMBER

Change-Id: Id88c18129bb773d979ad84bd0bb47188d74d4bc4
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/49762
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/northbridge/intel/sandybridge/northbridge.c b/src/northbridge/intel/sandybridge/northbridge.c
index dc1be32..2274355 100644
--- a/src/northbridge/intel/sandybridge/northbridge.c
+++ b/src/northbridge/intel/sandybridge/northbridge.c
@@ -35,39 +35,6 @@
 static const int legacy_hole_base_k = 0xa0000 / 1024;
 static const int legacy_hole_size_k = 384;
 
-int decode_pcie_bar(u32 *const base, u32 *const len)
-{
-	*base = 0;
-	*len = 0;
-
-	struct device *dev = pcidev_on_root(0, 0);
-	if (!dev)
-		return 0;
-
-	const u32 pciexbar_reg = pci_read_config32(dev, PCIEXBAR);
-
-	/* MMCFG not supported or not enabled */
-	if (!(pciexbar_reg & (1 << 0)))
-		return 0;
-
-	switch ((pciexbar_reg >> 1) & 3) {
-	case 0: /* 256MB */
-		*base = pciexbar_reg & (0x0f << 28);
-		*len = 256 * MiB;
-		return 1;
-	case 1: /* 128M */
-		*base = pciexbar_reg & (0x1f << 27);
-		*len = 128 * MiB;
-		return 1;
-	case 2: /* 64M */
-		*base = pciexbar_reg & (0x3f << 26);
-		*len = 64 * MiB;
-		return 1;
-	}
-
-	return 0;
-}
-
 static const char *northbridge_acpi_name(const struct device *dev)
 {
 	if (dev->path.type == DEVICE_PATH_DOMAIN)
@@ -84,10 +51,6 @@
 	return NULL;
 }
 
-/*
- * TODO We could determine how many PCIe busses we need in the bar.
- * For now, that number is hardcoded to a max of 64.
- */
 static struct device_operations pci_domain_ops = {
 	.read_resources    = pci_domain_read_resources,
 	.set_resources     = pci_domain_set_resources,
@@ -126,7 +89,6 @@
 
 static void mc_read_resources(struct device *dev)
 {
-	u32 pcie_config_base, pcie_config_len;
 	uint64_t tom, me_base, touud;
 	uint32_t tseg_base, uma_size, tolud;
 	uint16_t ggc;
@@ -135,11 +97,7 @@
 
 	pci_dev_read_resources(dev);
 
-	if (decode_pcie_bar(&pcie_config_base, &pcie_config_len)) {
-		const int buses = pcie_config_len / MiB;
-		struct resource *resource = new_resource(dev, PCIEXBAR);
-		mmconf_resource_init(resource, pcie_config_base, buses);
-	}
+	mmconf_resource(dev, PCIEXBAR);
 
 	/* Total Memory 2GB example:
 	 *