nb/intel/sandybridge/northbridge.c: Disbale non-active PEG devices

TXT SINIT ACM checks the PEG bridge memory ranges whether they are
correctly assigned in the MMIO space. If the bridge is enabled but no
device is attached to it, coreboot will not assign any resources (if
hotplug is not enabled). When SINIT ACM checks the ranges, it fails
on prefetchable range check.

Hide the PEG devices if the bridge is not active. PCIe bridges should
generally be hidden if hotplug is not enabled and there is no
downstream device.

Upstream-status: TBD

Signed-off-by: Michał Żygowski <michal.zygowski@3mdeb.com>

Author: miczyg1

src/northbridge/intel/sandybridge/northbridge.c

@@ -267,17 +267,17 @@ static void disable_peg(void)
 	reg = pci_read_config32(dev, DEVEN);
 
 	dev = pcidev_on_root(1, 2);
-	if (!dev || !dev->enabled) {
+	if (!dev || !dev->enabled || !dev_is_active_bridge(dev)) {
 		printk(BIOS_DEBUG, "Disabling PEG12.\n");
 		reg &= ~DEVEN_PEG12;
 	}
 	dev = pcidev_on_root(1, 1);
-	if (!dev || !dev->enabled) {
+	if (!dev || !dev->enabled || !dev_is_active_bridge(dev)) {
 		printk(BIOS_DEBUG, "Disabling PEG11.\n");
 		reg &= ~DEVEN_PEG11;
 	}
 	dev = pcidev_on_root(1, 0);
-	if (!dev || !dev->enabled) {
+	if (!dev || !dev->enabled || !dev_is_active_bridge(dev)) {
 		printk(BIOS_DEBUG, "Disabling PEG10.\n");
 		reg &= ~DEVEN_PEG10;
 	}
@@ -292,7 +292,7 @@ static void disable_peg(void)
 		reg &= ~DEVEN_D4EN;
 	}
 	dev = pcidev_on_root(6, 0);
-	if (!dev || !dev->enabled) {
+	if (!dev || !dev->enabled || !dev_is_active_bridge(dev)) {
 		printk(BIOS_DEBUG, "Disabling PEG60.\n");
 		reg &= ~DEVEN_PEG60;
 	}