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
  23 pgd_t swapper_pg_dir[PTRS_PER_PGD] __aligned(PAGE_SIZE);
  24 char empty_zero_page[PAGE_SIZE] __aligned(PAGE_SIZE);
  25 EXPORT_SYMBOL(empty_zero_page);
  26
  27 /* Default tot mem from .config */
  28 static unsigned long arc_mem_sz = 0x20000000;  /* some default */
  29
  30 /* User can over-ride above with "mem=nnn[KkMm]" in cmdline */
  31 static 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 }
  40 early_param("mem", setup_mem_sz);
  41
  42 void __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
  49 static 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 }
  63 early_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  */
  72 void __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  */
 134 void __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  */
 144 void __init_refok free_initmem(void)
 145 {
 146         free_initmem_default(-1);
 147 }
 148
 149 #ifdef CONFIG_BLK_DEV_INITRD
 150 void __init free_initrd_mem(unsigned long start, unsigned long end)
 151 {
 152         free_reserved_area((void *)start, (void *)end, -1, "initrd");
 153 }
 154 #endif