nb/intel/ironlake/acpi.c: Factor out PCIEXBAR decoding

Other northbridges have a `decode_pcie_bar` function. Since it's not
needed anywhere else, keep it as a static function for now.

Change-Id: Ide42ffcebb73c3e683e0ccaf0ab3aeae805d1123
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/44146
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>

1 files changed, 28 insertions, 28 deletions

diff --git a/src/northbridge/intel/ironlake/acpi.c b/src/northbridge/intel/ironlake/acpi.c
index c954086afb..688dd5fd81 100644
--- a/src/northbridge/intel/ironlake/acpi.c
+++ b/src/northbridge/intel/ironlake/acpi.c
@@ -3,48 +3,48 @@
 #define __SIMPLE_DEVICE__
 
 #include <types.h>
+#include <commonlib/helpers.h>
 #include <device/device.h>
 #include <device/pci_ops.h>
 #include "ironlake.h"
 
-unsigned long acpi_fill_mcfg(unsigned long current)
+static int decode_pcie_bar(u32 *const base, u32 *const len)
 {
-	u32 pciexbar = 0;
-	u32 pciexbar_reg;
-	int max_buses;
+	*base = 0;
+	*len = 0;
 
-	pciexbar_reg = pci_read_config32(QPI_SAD, SAD_PCIEXBAR);
+	const u32 pciexbar_reg = pci_read_config32(QPI_SAD, SAD_PCIEXBAR);
 
-	// MMCFG not supported or not enabled.
 	if (!(pciexbar_reg & (1 << 0)))
-		return current;
+		return 0;
 
 	switch ((pciexbar_reg >> 1) & 3) {
-	case 0:		// 256MB
-		pciexbar =
-		    pciexbar_reg & ((1 << 31) | (1 << 30) | (1 << 29) |
-				    (1 << 28));
-		max_buses = 256;
-		break;
-	case 1:		// 128M
-		pciexbar =
-		    pciexbar_reg & ((1 << 31) | (1 << 30) | (1 << 29) |
-				    (1 << 28) | (1 << 27));
-		max_buses = 128;
-		break;
-	case 2:		// 64M
-		pciexbar =
-		    pciexbar_reg & ((1 << 31) | (1 << 30) | (1 << 29) |
-				    (1 << 28) | (1 << 27) | (1 << 26));
-		max_buses = 64;
-		break;
-	default:		// RSVD
-		return current;
+	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;
 	}
 
-	if (!pciexbar)
+	return 0;
+}
+
+unsigned long acpi_fill_mcfg(unsigned long current)
+{
+	u32 length, pciexbar;
+
+	if (!decode_pcie_bar(&pciexbar, &length))
 		return current;
 
+	const int max_buses = length / MiB;
+
 	current += acpi_create_mcfg_mmconfig((acpi_mcfg_mmconfig_t *) current,
 					     pciexbar, 0x0, 0x0, max_buses - 1);