amdtopology.c
// SPDX-License-Identifier: GPL-2.0
/*
* 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/nodemask.h>
#include <linux/memblock.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/api.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;
}
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++;
limit <<= 24;
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 boot-time SMP configuration:
*/
early_get_smp_config();
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;
}