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 9cc813e29706..3903efbca535 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);