amdtopology.c

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/*
 * AMD NUMA support.
 * Discover the memory map and associated nodes.
 *
 * This version reads it directly from the AMD northbridge.
 *
 * Copyright 2002,2003 Andi Kleen, SuSE Labs.
 */
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/module.h>
#include <linux/nodemask.h>
#include <linux/memblock.h>
#include <linux/bootmem.h>

#include <asm/io.h>
#include <linux/pci_ids.h>
#include <linux/acpi.h>
#include <asm/types.h>
#include <asm/mmzone.h>
#include <asm/proto.h>
#include <asm/e820.h>
#include <asm/pci-direct.h>
#include <asm/numa.h>
#include <asm/mpspec.h>
#include <asm/apic.h>
#include <asm/amd_nb.h>

static unsigned char __initdata nodeids[8];

static __init int find_northbridge(void)
{
    int num;

    for (num = 0; num < 32; num++) {
        u32 header;

        header = read_pci_config(0, num, 0, 0x00);
        if (header != (PCI_VENDOR_ID_AMD | (0x1100<<16)) &&
            header != (PCI_VENDOR_ID_AMD | (0x1200<<16)) &&
            header != (PCI_VENDOR_ID_AMD | (0x1300<<16)))
            continue;

        header = read_pci_config(0, num, 1, 0x00);
        if (header != (PCI_VENDOR_ID_AMD | (0x1101<<16)) &&
            header != (PCI_VENDOR_ID_AMD | (0x1201<<16)) &&
            header != (PCI_VENDOR_ID_AMD | (0x1301<<16)))
            continue;
        return num;
    }

    return -ENOENT;
}

static __init void early_get_boot_cpu_id(void)
{
    /*
     * need to get the APIC ID of the BSP so can use that to
     * create apicid_to_node in amd_scan_nodes()
     */
#ifdef CONFIG_X86_MPPARSE
    /*
     * get boot-time SMP configuration:
     */
    if (smp_found_config)
        early_get_smp_config();
#endif
}

int __init amd_numa_init(void)
{
    u64 start = PFN_PHYS(0);
    u64 end = PFN_PHYS(max_pfn);
    unsigned numnodes;
    u64 prevbase;
    int i, j, nb;
    u32 nodeid, reg;
    unsigned int bits, cores, apicid_base;

    if (!early_pci_allowed())
        return -EINVAL;

    nb = find_northbridge();
    if (nb < 0)
        return nb;

    pr_info("Scanning NUMA topology in Northbridge %d\n", nb);

    reg = read_pci_config(0, nb, 0, 0x60);
    numnodes = ((reg >> 4) & 0xF) + 1;
    if (numnodes <= 1)
        return -ENOENT;

    pr_info("Number of physical nodes %d\n", numnodes);

    prevbase = 0;
    for (i = 0; i < 8; i++) {
        u64 base, limit;

        base = read_pci_config(0, nb, 1, 0x40 + i*8);
        limit = read_pci_config(0, nb, 1, 0x44 + i*8);

        nodeids[i] = nodeid = limit & 7;
        if ((base & 3) == 0) {
            if (i < numnodes)
                pr_info("Skipping disabled node %d\n", i);
            continue;
        }
        if (nodeid >= numnodes) {
            pr_info("Ignoring excess node %d (%Lx:%Lx)\n", nodeid,
                base, limit);
            continue;
        }

        if (!limit) {
            pr_info("Skipping node entry %d (base %Lx)\n",
                i, base);
            continue;
        }
        if ((base >> 8) & 3 || (limit >> 8) & 3) {
            pr_err("Node %d using interleaving mode %Lx/%Lx\n",
                   nodeid, (base >> 8) & 3, (limit >> 8) & 3);
            return -EINVAL;
        }
        if (node_isset(nodeid, numa_nodes_parsed)) {
            pr_info("Node %d already present, skipping\n",
                nodeid);
            continue;
        }

        limit >>= 16;
        limit <<= 24;
        limit |= (1<<24)-1;
        limit++;

        if (limit > end)
            limit = end;
        if (limit <= base)
            continue;

        base >>= 16;
        base <<= 24;

        if (base < start)
            base = start;
        if (limit > end)
            limit = end;
        if (limit == base) {
            pr_err("Empty node %d\n", nodeid);
            continue;
        }
        if (limit < base) {
            pr_err("Node %d bogus settings %Lx-%Lx.\n",
                   nodeid, base, limit);
            continue;
        }

        /* Could sort here, but pun for now. Should not happen anyroads. */
        if (prevbase > base) {
            pr_err("Node map not sorted %Lx,%Lx\n",
                   prevbase, base);
            return -EINVAL;
        }

        pr_info("Node %d MemBase %016Lx Limit %016Lx\n",
            nodeid, base, limit);

        prevbase = base;
        numa_add_memblk(nodeid, base, limit);
        node_set(nodeid, numa_nodes_parsed);
    }

    if (!nodes_weight(numa_nodes_parsed))
        return -ENOENT;

    /*
     * We seem to have valid NUMA configuration.  Map apicids to nodes
     * using the coreid bits from early_identify_cpu.
     */
    bits = boot_cpu_data.x86_coreid_bits;
    cores = 1 << bits;
    apicid_base = 0;

    /* get the APIC ID of the BSP early for systems with apicid lifting */
    early_get_boot_cpu_id();
    if (boot_cpu_physical_apicid > 0) {
        pr_info("BSP APIC ID: %02x\n", boot_cpu_physical_apicid);
        apicid_base = boot_cpu_physical_apicid;
    }

    for_each_node_mask(i, numa_nodes_parsed)
        for (j = apicid_base; j < cores + apicid_base; j++)
            set_apicid_to_node((i << bits) + j, i);

    return 0;
}