From cff4d1649f8a2b890521b53d8b7a6cb5c210d50e Mon Sep 17 00:00:00 2001
From: Angel Pons <th3fanbus@gmail.com>
Date: Mon, 3 Aug 2020 16:11:53 +0200
Subject: [PATCH] nb/intel/i945: Refactor `get_pcie_bar`

Turn it into `decode_pcie_bar`, taken from gm45.

Change-Id: I81a398535f18ced10b5521bddcf21f3568e1d854
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/44144
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
---
 src/northbridge/intel/i945/northbridge.c | 39 ++++++++++++------------
 1 file changed, 20 insertions(+), 19 deletions(-)

diff --git a/src/northbridge/intel/i945/northbridge.c b/src/northbridge/intel/i945/northbridge.c
index 0e8ea7e77e..20c911620c 100644
--- a/src/northbridge/intel/i945/northbridge.c
+++ b/src/northbridge/intel/i945/northbridge.c
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
 #include <cbmem.h>
+#include <commonlib/helpers.h>
 #include <console/console.h>
 #include <device/pci_ops.h>
 #include <stdint.h>
@@ -11,32 +12,33 @@
 #include <cpu/intel/smm_reloc.h>
 #include "i945.h"
 
-static int get_pcie_bar(u32 *base)
+static int decode_pcie_bar(u32 *const base, u32 *const len)
 {
-	struct device *dev;
-	u32 pciexbar_reg;
-
 	*base = 0;
+	*len = 0;
 
-	dev = pcidev_on_root(0, 0);
+	struct device *dev = pcidev_on_root(0, 0);
 	if (!dev)
 		return 0;
 
-	pciexbar_reg = pci_read_config32(dev, PCIEXBAR);
+	const u32 pciexbar_reg = pci_read_config32(dev, PCIEXBAR);
 
 	if (!(pciexbar_reg & (1 << 0)))
 		return 0;
 
 	switch ((pciexbar_reg >> 1) & 3) {
-	case 0: // 256MB
-		*base = pciexbar_reg & ((1 << 31)|(1 << 30)|(1 << 29)|(1 << 28));
-		return 256;
-	case 1: // 128M
-		*base = pciexbar_reg & ((1 << 31)|(1 << 30)|(1 << 29)|(1 << 28)|(1 << 27));
-		return 128;
-	case 2: // 64M
-		*base = pciexbar_reg & ((1 << 31)|(1 << 30)|(1 << 29)|(1 << 28)|(1 << 27)|(1 << 26));
-		return 64;
+	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;
@@ -162,13 +164,12 @@ static struct device_operations pci_domain_ops = {
 
 static void mc_read_resources(struct device *dev)
 {
-	u32 pcie_config_base;
-	int buses;
+	u32 pcie_config_base, pcie_config_len;
 
 	pci_dev_read_resources(dev);
 
-	buses = get_pcie_bar(&pcie_config_base);
-	if (buses) {
+	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);
 	}