x86: get mp_bus_to_node early

Currently, on an amd k8 system with multi ht chains, the numa_node of
pci devices under /sys/devices/pci0000:80/* is always 0, even if that
chain is on node 1 or 2 or 3.

Workaround: pcibus_to_node(bus) is used when we want to get the node that
pci_device is on.

In struct device, we already have numa_node member, and we could use
dev_to_node()/set_dev_node() to get and set numa_node in the device.
set_dev_node is called in pci_device_add() with pcibus_to_node(bus),
and pcibus_to_node uses bus->sysdata for nodeid.

The problem is when pci_add_device is called, bus->sysdata is not assigned
correct nodeid yet. The result is that numa_node will always be 0.

pcibios_scan_root and pci_scan_root could take sysdata. So we need to get
mp_bus_to_node mapping before these two are called, and thus
get_mp_bus_to_node could get correct node for sysdata in root bus.

In scanning of the root bus, all child busses will take parent bus sysdata.
So all pci_device->dev.numa_node will be assigned correctly and automatically.

Later we could use dev_to_node(&pci_dev->dev) to get numa_node, and we
could also could make other bus specific device get the correct numa_node
too.

This is an updated version of pci_sysdata and Jeff's pci_domain patch.

[ mingo@elte.hu: build fix ]

Signed-off-by: Yinghai Lu <yinghai.lu@sun.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 66 insertions, 26 deletions

diff --git a/arch/x86/pci/k8-bus_64.c b/arch/x86/pci/k8-bus_64.c
index 9cc813e2970..3903efbca53 100644
--- a/arch/x86/pci/k8-bus_64.c
+++ b/arch/x86/pci/k8-bus_64.c
@@ -1,7 +1,9 @@
 #include <linux/init.h>
 #include <linux/pci.h>
+#include <asm/pci-direct.h>
 #include <asm/mpspec.h>
 #include <linux/cpumask.h>
+#include <linux/topology.h>
 
 /*
  * This discovers the pcibus <-> node mapping on AMD K8.
@@ -20,64 +22,102 @@
 #define SUBORDINATE_LDT_BUS_NUMBER(dword) ((dword >> 16) & 0xFF)
 #define PCI_DEVICE_ID_K8HTCONFIG 0x1100
 
+#ifdef CONFIG_NUMA
+
+#define BUS_NR 256
+
+static int mp_bus_to_node[BUS_NR];
+
+void set_mp_bus_to_node(int busnum, int node)
+{
+	if (busnum >= 0 &&  busnum < BUS_NR)
+		mp_bus_to_node[busnum] = node;
+}
+
+int get_mp_bus_to_node(int busnum)
+{
+	int node = -1;
+
+	if (busnum < 0 || busnum > (BUS_NR - 1))
+		return node;
+
+	node = mp_bus_to_node[busnum];
+
+	/*
+	 * let numa_node_id to decide it later in dma_alloc_pages
+	 * if there is no ram on that node
+	 */
+	if (node != -1 && !node_online(node))
+		node = -1;
+
+	return node;
+}
+
+#endif
+
 /**
- * fill_mp_bus_to_cpumask()
+ * early_fill_mp_bus_to_node()
+ * called before pcibios_scan_root and pci_scan_bus
  * fills the mp_bus_to_cpumask array based according to the LDT Bus Number
  * Registers found in the K8 northbridge
  */
 __init static int
-fill_mp_bus_to_cpumask(void)
+early_fill_mp_bus_to_node(void)
 {
-	struct pci_dev *nb_dev = NULL;
+#ifdef CONFIG_NUMA
 	int i, j;
+	unsigned slot;
 	u32 ldtbus, nid;
+	u32 id;
 	static int lbnr[3] = {
 		LDT_BUS_NUMBER_REGISTER_0,
 		LDT_BUS_NUMBER_REGISTER_1,
 		LDT_BUS_NUMBER_REGISTER_2
 	};
 
-	while ((nb_dev = pci_get_device(PCI_VENDOR_ID_AMD,
-			PCI_DEVICE_ID_K8HTCONFIG, nb_dev))) {
-		pci_read_config_dword(nb_dev, NODE_ID_REGISTER, &nid);
+	for (i = 0; i < BUS_NR; i++)
+		mp_bus_to_node[i] = -1;
+
+	if (!early_pci_allowed())
+		return -1;
+
+	for (slot = 0x18; slot < 0x20; slot++) {
+		id = read_pci_config(0, slot, 0, PCI_VENDOR_ID);
+		if (id != (PCI_VENDOR_ID_AMD | (PCI_DEVICE_ID_K8HTCONFIG<<16)))
+			break;
+		nid = read_pci_config(0, slot, 0, NODE_ID_REGISTER);
 
 		for (i = 0; i < NR_LDT_BUS_NUMBER_REGISTERS; i++) {
-			pci_read_config_dword(nb_dev, lbnr[i], &ldtbus);
+			ldtbus = read_pci_config(0, slot, 0, lbnr[i]);
 			/*
 			 * if there are no busses hanging off of the current
 			 * ldt link then both the secondary and subordinate
 			 * bus number fields are set to 0.
-			 * 
+			 *
 			 * RED-PEN
 			 * This is slightly broken because it assumes
- 			 * HT node IDs == Linux node ids, which is not always
+			 * HT node IDs == Linux node ids, which is not always
 			 * true. However it is probably mostly true.
 			 */
 			if (!(SECONDARY_LDT_BUS_NUMBER(ldtbus) == 0
 				&& SUBORDINATE_LDT_BUS_NUMBER(ldtbus) == 0)) {
 				for (j = SECONDARY_LDT_BUS_NUMBER(ldtbus);
 				     j <= SUBORDINATE_LDT_BUS_NUMBER(ldtbus);
-				     j++) { 
-					struct pci_bus *bus;
-					struct pci_sysdata *sd;
-
-					long node = NODE_ID(nid);
-					/* Algorithm a bit dumb, but
- 					   it shouldn't matter here */
-					bus = pci_find_bus(0, j);
-					if (!bus)
-						continue;
-					if (!node_online(node))
-						node = 0;
-
-					sd = bus->sysdata;
-					sd->node = node;
-				}		
+				     j++) {
+					int node = NODE_ID(nid);
+					mp_bus_to_node[j] = (unsigned char)node;
+				}
 			}
 		}
 	}
 
+	for (i = 0; i < BUS_NR; i++) {
+		int node = mp_bus_to_node[i];
+		if (node >= 0)
+			printk(KERN_DEBUG "bus: %02x to node: %02x\n", i, node);
+	}
+#endif
 	return 0;
 }
 
-fs_initcall(fill_mp_bus_to_cpumask);
+postcore_initcall(early_fill_mp_bus_to_node);