device/device.h: Drop multiple links

Multiple links are unused throughout the tree and make the code more
confusing as an iteration over all busses is needed to get downstream
devices. This also not done consistently e.g. the allocator does not
care about multiple links on busses. A better way of dealing multiple
links below a device is to feature dummy devices with each their
respective bus.

This drops the sconfig capability to declare the same device multiple
times which was previously used to declare multiple links.

Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Change-Id: Iab6fe269faef46ae77ed1ea425440cf5c7dbd49b
Reviewed-on: https://review.coreboot.org/c/coreboot/+/78328
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Jincheng Li <jincheng.li@intel.com>
Reviewed-by: Lean Sheng Tan <sheng.tan@9elements.com>

1 files changed, 40 insertions, 43 deletions

diff --git a/src/arch/x86/mpspec.c b/src/arch/x86/mpspec.c
index 7744f68e85..3ddee2f6b9 100644
--- a/src/arch/x86/mpspec.c
+++ b/src/arch/x86/mpspec.c
@@ -282,48 +282,46 @@ void smp_write_intsrc_pci_bridge(struct mp_config_table *mc,
 	int srcbus;
 	int slot;
 
-	struct bus *link;
 	unsigned char dstirq_x[4];
 
-	for (link = dev->link_list; link; link = link->next) {
+	if (!dev->link_list)
+		return;
 
-		child = link->children;
-		srcbus = link->secondary;
+	child = dev->link_list->children;
+	srcbus = dev->link_list->secondary;
 
-		while (child) {
-			if (child->path.type != DEVICE_PATH_PCI)
-				goto next;
+	while (child) {
+		if (child->path.type != DEVICE_PATH_PCI)
+			goto next;
 
-			slot = (child->path.pci.devfn >> 3);
-			/* round pins */
-			for (i = 0; i < 4; i++)
-				dstirq_x[i] = dstirq[(i + slot) % 4];
-
-			if ((child->class >> 16) != PCI_BASE_CLASS_BRIDGE) {
-				/* pci device */
-				printk(BIOS_DEBUG, "route irq: %s\n",
-					dev_path(child));
-				for (i = 0; i < 4; i++)
-					smp_write_intsrc(mc, irqtype, irqflag,
-						srcbus, (slot<<2)|i, dstapic,
-						dstirq_x[i]);
-				goto next;
-			}
+		slot = (child->path.pci.devfn >> 3);
+		/* round pins */
+		for (i = 0; i < 4; i++)
+			dstirq_x[i] = dstirq[(i + slot) % 4];
 
-			switch (child->class>>8) {
-			case PCI_CLASS_BRIDGE_PCI:
-			case PCI_CLASS_BRIDGE_PCMCIA:
-			case PCI_CLASS_BRIDGE_CARDBUS:
-				printk(BIOS_DEBUG, "route irq bridge: %s\n",
-					dev_path(child));
-				smp_write_intsrc_pci_bridge(mc, irqtype,
-					irqflag, child, dstapic, dstirq_x);
-			}
+		if ((child->class >> 16) != PCI_BASE_CLASS_BRIDGE) {
+			/* pci device */
+			printk(BIOS_DEBUG, "route irq: %s\n",
+			       dev_path(child));
+			for (i = 0; i < 4; i++)
+				smp_write_intsrc(mc, irqtype, irqflag,
+						 srcbus, (slot<<2)|i, dstapic,
+						 dstirq_x[i]);
+			goto next;
+		}
 
-next:
-			child = child->sibling;
+		switch (child->class>>8) {
+		case PCI_CLASS_BRIDGE_PCI:
+		case PCI_CLASS_BRIDGE_PCMCIA:
+		case PCI_CLASS_BRIDGE_CARDBUS:
+			printk(BIOS_DEBUG, "route irq bridge: %s\n",
+			       dev_path(child));
+			smp_write_intsrc_pci_bridge(mc, irqtype,
+						    irqflag, child, dstapic, dstirq_x);
 		}
 
+next:
+		child = child->sibling;
 	}
 }
 
@@ -478,17 +476,16 @@ void mptable_write_buses(struct mp_config_table *mc, int *max_pci_bus,
 	memset(buses, 0, sizeof(buses));
 
 	for (dev = all_devices; dev; dev = dev->next) {
-		struct bus *bus;
-		for (bus = dev->link_list; bus; bus = bus->next) {
-			if (bus->secondary > 255) {
-				printk(BIOS_ERR,
-					"A bus claims to have a bus ID > 255?!? Aborting");
-				return;
-			}
-			buses[bus->secondary] = 1;
-			if (highest < bus->secondary)
-				highest = bus->secondary;
+		struct bus *bus = dev->link_list;
+		if (!bus)
+			continue;
+		if (bus->secondary > 255) {
+			printk(BIOS_ERR, "A bus claims to have a bus ID > 255?!? Aborting\n");
+			return;
 		}
+		buses[bus->secondary] = 1;
+		if (highest < bus->secondary)
+			highest = bus->secondary;
 	}
 	for (i = 0; i <= highest; i++) {
 		if (buses[i]) {