LXR linux/arch/arc/mm/init.c

   1/*
   2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License version 2 as
   6 * published by the Free Software Foundation.
   7 */
   8
   9#include <linux/kernel.h>
  10#include <linux/mm.h>
  11#include <linux/bootmem.h>
  12#include <linux/memblock.h>
  13#ifdef CONFIG_BLK_DEV_INITRD
  14#include <linux/initrd.h>
  15#endif
  16#include <linux/swap.h>
  17#include <linux/module.h>
  18#include <asm/page.h>
  19#include <asm/pgalloc.h>
  20#include <asm/sections.h>
  21#include <asm/arcregs.h>
  22
  23pgd_t swapper_pg_dir[PTRS_PER_PGD] __aligned(PAGE_SIZE);
  24char empty_zero_page[PAGE_SIZE] __aligned(PAGE_SIZE);
  25EXPORT_SYMBOL(empty_zero_page);
  26
  27/* Default tot mem from .config */
  28static unsigned long arc_mem_sz = 0x20000000;  /* some default */
  29
  30/* User can over-ride above with "mem=nnn[KkMm]" in cmdline */
  31static int __init setup_mem_sz(char *str)
  32{
  33        arc_mem_sz = memparse(str, NULL) & PAGE_MASK;
  34
  35        /* early console might not be setup yet - it will show up later */
  36        pr_info("\"mem=%s\": mem sz set to %ldM\n", str, TO_MB(arc_mem_sz));
  37
  38        return 0;
  39}
  40early_param("mem", setup_mem_sz);
  41
  42void __init early_init_dt_add_memory_arch(u64 base, u64 size)
  43{
  44        arc_mem_sz = size & PAGE_MASK;
  45        pr_info("Memory size set via devicetree %ldM\n", TO_MB(arc_mem_sz));
  46}
  47
  48#ifdef CONFIG_BLK_DEV_INITRD
  49static int __init early_initrd(char *p)
  50{
  51        unsigned long start, size;
  52        char *endp;
  53
  54        start = memparse(p, &endp);
  55        if (*endp == ',') {
  56                size = memparse(endp + 1, NULL);
  57
  58                initrd_start = (unsigned long)__va(start);
  59                initrd_end = (unsigned long)__va(start + size);
  60        }
  61        return 0;
  62}
  63early_param("initrd", early_initrd);
  64#endif
  65
  66/*
  67 * First memory setup routine called from setup_arch()
  68 * 1. setup swapper's mm @init_mm
  69 * 2. Count the pages we have and setup bootmem allocator
  70 * 3. zone setup
  71 */
  72void __init setup_arch_memory(void)
  73{
  74        unsigned long zones_size[MAX_NR_ZONES] = { 0, 0 };
  75        unsigned long end_mem = CONFIG_LINUX_LINK_BASE + arc_mem_sz;
  76
  77        init_mm.start_code = (unsigned long)_text;
  78        init_mm.end_code = (unsigned long)_etext;
  79        init_mm.end_data = (unsigned long)_edata;
  80        init_mm.brk = (unsigned long)_end;
  81
  82        /*
  83         * We do it here, so that memory is correctly instantiated
  84         * even if "mem=xxx" cmline over-ride is given and/or
  85         * DT has memory node. Each causes an update to @arc_mem_sz
  86         * and we finally add memory one here
  87         */
  88        memblock_add(CONFIG_LINUX_LINK_BASE, arc_mem_sz);
  89
  90        /*------------- externs in mm need setting up ---------------*/
  91
  92        /* first page of system - kernel .vector starts here */
  93        min_low_pfn = PFN_DOWN(CONFIG_LINUX_LINK_BASE);
  94
  95        /* Last usable page of low mem (no HIGHMEM yet for ARC port) */
  96        max_low_pfn = max_pfn = PFN_DOWN(end_mem);
  97
  98        max_mapnr = max_low_pfn - min_low_pfn;
  99
 100        /*------------- reserve kernel image -----------------------*/
 101        memblock_reserve(CONFIG_LINUX_LINK_BASE,
 102                         __pa(_end) - CONFIG_LINUX_LINK_BASE);
 103
 104#ifdef CONFIG_BLK_DEV_INITRD
 105        /*------------- reserve initrd image -----------------------*/
 106        if (initrd_start)
 107                memblock_reserve(__pa(initrd_start), initrd_end - initrd_start);
 108#endif
 109
 110        memblock_dump_all();
 111
 112        /*-------------- node setup --------------------------------*/
 113        memset(zones_size, 0, sizeof(zones_size));
 114        zones_size[ZONE_NORMAL] = max_low_pfn - min_low_pfn;
 115
 116        /*
 117         * We can't use the helper free_area_init(zones[]) because it uses
 118         * PAGE_OFFSET to compute the @min_low_pfn which would be wrong
 119         * when our kernel doesn't start at PAGE_OFFSET, i.e.
 120         * PAGE_OFFSET != CONFIG_LINUX_LINK_BASE
 121         */
 122        free_area_init_node(0,                  /* node-id */
 123                            zones_size,         /* num pages per zone */
 124                            min_low_pfn,        /* first pfn of node */
 125                            NULL);              /* NO holes */
 126}
 127
 128/*
 129 * mem_init - initializes memory
 130 *
 131 * Frees up bootmem
 132 * Calculates and displays memory available/used
 133 */
 134void __init mem_init(void)
 135{
 136        high_memory = (void *)(CONFIG_LINUX_LINK_BASE + arc_mem_sz);
 137        free_all_bootmem();
 138        mem_init_print_info(NULL);
 139}
 140
 141/*
 142 * free_initmem: Free all the __init memory.
 143 */
 144void __init_refok free_initmem(void)
 145{
 146        free_initmem_default(-1);
 147}
 148
 149#ifdef CONFIG_BLK_DEV_INITRD
 150void __init free_initrd_mem(unsigned long start, unsigned long end)
 151{
 152        free_reserved_area((void *)start, (void *)end, -1, "initrd");
 153}
 154#endif
 155