1/*
  2 * This file is subject to the terms and conditions of the GNU General Public
  3 * License.  See the file "COPYING" in the main directory of this archive
  4 * for more details.
  5 *
  6 * This file contains NUMA specific variables and functions which can
  7 * be split away from DISCONTIGMEM and are used on NUMA machines with
  8 * contiguous memory.
  9 * 
 10 *                         2002/08/07 Erich Focht <efocht@ess.nec.de>
 11 */
 12
 13#include <linux/cpu.h>
 14#include <linux/kernel.h>
 15#include <linux/mm.h>
 16#include <linux/node.h>
 17#include <linux/init.h>
 18#include <linux/memblock.h>
 19#include <linux/module.h>
 20#include <asm/mmzone.h>
 21#include <asm/numa.h>
 22
 23
 24/*
 25 * The following structures are usually initialized by ACPI or
 26 * similar mechanisms and describe the NUMA characteristics of the machine.
 27 */
 28int num_node_memblks;
 29struct node_memblk_s node_memblk[NR_NODE_MEMBLKS];
 30struct node_cpuid_s node_cpuid[NR_CPUS] =
 31	{ [0 ... NR_CPUS-1] = { .phys_id = 0, .nid = NUMA_NO_NODE } };
 32
 33/*
 34 * This is a matrix with "distances" between nodes, they should be
 35 * proportional to the memory access latency ratios.
 36 */
 37u8 numa_slit[MAX_NUMNODES * MAX_NUMNODES];
 38
 39int __node_distance(int from, int to)
 40{
 41	return slit_distance(from, to);
 42}
 43EXPORT_SYMBOL(__node_distance);
 44
 45/* Identify which cnode a physical address resides on */
 46int
 47paddr_to_nid(unsigned long paddr)
 48{
 49	int	i;
 50
 51	for (i = 0; i < num_node_memblks; i++)
 52		if (paddr >= node_memblk[i].start_paddr &&
 53		    paddr < node_memblk[i].start_paddr + node_memblk[i].size)
 54			break;
 55
 56	return (i < num_node_memblks) ? node_memblk[i].nid : (num_node_memblks ? -1 : 0);
 57}
 58EXPORT_SYMBOL(paddr_to_nid);
 59
 60#if defined(CONFIG_SPARSEMEM) && defined(CONFIG_NUMA)
 61/*
 62 * Because of holes evaluate on section limits.
 63 * If the section of memory exists, then return the node where the section
 64 * resides.  Otherwise return node 0 as the default.  This is used by
 65 * SPARSEMEM to allocate the SPARSEMEM sectionmap on the NUMA node where
 66 * the section resides.
 67 */
 68int __meminit __early_pfn_to_nid(unsigned long pfn,
 69					struct mminit_pfnnid_cache *state)
 70{
 71	int i, section = pfn >> PFN_SECTION_SHIFT, ssec, esec;
 72
 73	if (section >= state->last_start && section < state->last_end)
 74		return state->last_nid;
 75
 76	for (i = 0; i < num_node_memblks; i++) {
 77		ssec = node_memblk[i].start_paddr >> PA_SECTION_SHIFT;
 78		esec = (node_memblk[i].start_paddr + node_memblk[i].size +
 79			((1L << PA_SECTION_SHIFT) - 1)) >> PA_SECTION_SHIFT;
 80		if (section >= ssec && section < esec) {
 81			state->last_start = ssec;
 82			state->last_end = esec;
 83			state->last_nid = node_memblk[i].nid;
 84			return node_memblk[i].nid;
 85		}
 86	}
 87
 88	return -1;
 89}
 90
 91void numa_clear_node(int cpu)
 92{
 93	unmap_cpu_from_node(cpu, NUMA_NO_NODE);
 94}
 95
 96#ifdef CONFIG_MEMORY_HOTPLUG
 97/*
 98 *  SRAT information is stored in node_memblk[], then we can use SRAT
 99 *  information at memory-hot-add if necessary.
100 */
101
102int memory_add_physaddr_to_nid(u64 addr)
103{
104	int nid = paddr_to_nid(addr);
105	if (nid < 0)
106		return 0;
107	return nid;
108}
109#endif
110#endif