linux/arch/cris/kernel/setup.c
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   1/*
   2 *
   3 *  linux/arch/cris/kernel/setup.c
   4 *
   5 *  Copyright (C) 1995  Linus Torvalds
   6 *  Copyright (c) 2001  Axis Communications AB
   7 */
   8
   9/*
  10 * This file handles the architecture-dependent parts of initialization
  11 */
  12
  13#include <linux/init.h>
  14#include <linux/mm.h>
  15#include <linux/bootmem.h>
  16#include <asm/pgtable.h>
  17#include <linux/seq_file.h>
  18#include <linux/screen_info.h>
  19#include <linux/utsname.h>
  20#include <linux/pfn.h>
  21#include <linux/cpu.h>
  22#include <asm/setup.h>
  23
  24/*
  25 * Setup options
  26 */
  27struct screen_info screen_info;
  28
  29extern int root_mountflags;
  30extern char _etext, _edata, _end;
  31
  32char __initdata cris_command_line[COMMAND_LINE_SIZE] = { 0, };
  33
  34extern const unsigned long text_start, edata; /* set by the linker script */
  35extern unsigned long dram_start, dram_end;
  36
  37extern unsigned long romfs_start, romfs_length, romfs_in_flash; /* from head.S */
  38
  39static struct cpu cpu_devices[NR_CPUS];
  40
  41extern void show_etrax_copyright(void);         /* arch-vX/kernel/setup.c */
  42
  43/* This mainly sets up the memory area, and can be really confusing.
  44 *
  45 * The physical DRAM is virtually mapped into dram_start to dram_end
  46 * (usually c0000000 to c0000000 + DRAM size). The physical address is
  47 * given by the macro __pa().
  48 *
  49 * In this DRAM, the kernel code and data is loaded, in the beginning.
  50 * It really starts at c0004000 to make room for some special pages -
  51 * the start address is text_start. The kernel data ends at _end. After
  52 * this the ROM filesystem is appended (if there is any).
  53 *
  54 * Between this address and dram_end, we have RAM pages usable to the
  55 * boot code and the system.
  56 *
  57 */
  58
  59void __init setup_arch(char **cmdline_p)
  60{
  61        extern void init_etrax_debug(void);
  62        unsigned long bootmap_size;
  63        unsigned long start_pfn, max_pfn;
  64        unsigned long memory_start;
  65
  66        /* register an initial console printing routine for printk's */
  67
  68        init_etrax_debug();
  69
  70        /* we should really poll for DRAM size! */
  71
  72        high_memory = &dram_end;
  73
  74        if(romfs_in_flash || !romfs_length) {
  75                /* if we have the romfs in flash, or if there is no rom filesystem,
  76                 * our free area starts directly after the BSS
  77                 */
  78                memory_start = (unsigned long) &_end;
  79        } else {
  80                /* otherwise the free area starts after the ROM filesystem */
  81                printk("ROM fs in RAM, size %lu bytes\n", romfs_length);
  82                memory_start = romfs_start + romfs_length;
  83        }
  84
  85        /* process 1's initial memory region is the kernel code/data */
  86
  87        init_mm.start_code = (unsigned long) &text_start;
  88        init_mm.end_code =   (unsigned long) &_etext;
  89        init_mm.end_data =   (unsigned long) &_edata;
  90        init_mm.brk =        (unsigned long) &_end;
  91
  92        /* min_low_pfn points to the start of DRAM, start_pfn points
  93         * to the first DRAM pages after the kernel, and max_low_pfn
  94         * to the end of DRAM.
  95         */
  96
  97        /*
  98         * partially used pages are not usable - thus
  99         * we are rounding upwards:
 100         */
 101
 102        start_pfn = PFN_UP(memory_start);  /* usually c0000000 + kernel + romfs */
 103        max_pfn =   PFN_DOWN((unsigned long)high_memory); /* usually c0000000 + dram size */
 104
 105        /*
 106         * Initialize the boot-time allocator (start, end)
 107         *
 108         * We give it access to all our DRAM, but we could as well just have
 109         * given it a small slice. No point in doing that though, unless we
 110         * have non-contiguous memory and want the boot-stuff to be in, say,
 111         * the smallest area.
 112         *
 113         * It will put a bitmap of the allocated pages in the beginning
 114         * of the range we give it, but it won't mark the bitmaps pages
 115         * as reserved. We have to do that ourselves below.
 116         *
 117         * We need to use init_bootmem_node instead of init_bootmem
 118         * because our map starts at a quite high address (min_low_pfn).
 119         */
 120
 121        max_low_pfn = max_pfn;
 122        min_low_pfn = PAGE_OFFSET >> PAGE_SHIFT;
 123
 124        bootmap_size = init_bootmem_node(NODE_DATA(0), start_pfn,
 125                                         min_low_pfn,
 126                                         max_low_pfn);
 127
 128        /* And free all memory not belonging to the kernel (addr, size) */
 129
 130        free_bootmem(PFN_PHYS(start_pfn), PFN_PHYS(max_pfn - start_pfn));
 131
 132        /*
 133         * Reserve the bootmem bitmap itself as well. We do this in two
 134         * steps (first step was init_bootmem()) because this catches
 135         * the (very unlikely) case of us accidentally initializing the
 136         * bootmem allocator with an invalid RAM area.
 137         *
 138         * Arguments are start, size
 139         */
 140
 141        reserve_bootmem(PFN_PHYS(start_pfn), bootmap_size, BOOTMEM_DEFAULT);
 142
 143        /* paging_init() sets up the MMU and marks all pages as reserved */
 144
 145        paging_init();
 146
 147        *cmdline_p = cris_command_line;
 148
 149#ifdef CONFIG_ETRAX_CMDLINE
 150        if (!strcmp(cris_command_line, "")) {
 151                strlcpy(cris_command_line, CONFIG_ETRAX_CMDLINE, COMMAND_LINE_SIZE);
 152                cris_command_line[COMMAND_LINE_SIZE - 1] = '\0';
 153        }
 154#endif
 155
 156        /* Save command line for future references. */
 157        memcpy(boot_command_line, cris_command_line, COMMAND_LINE_SIZE);
 158        boot_command_line[COMMAND_LINE_SIZE - 1] = '\0';
 159
 160        /* give credit for the CRIS port */
 161        show_etrax_copyright();
 162
 163        /* Setup utsname */
 164        strcpy(init_utsname()->machine, cris_machine_name);
 165}
 166
 167static void *c_start(struct seq_file *m, loff_t *pos)
 168{
 169        return *pos < NR_CPUS ? (void *)(int)(*pos + 1): NULL;
 170}
 171
 172static void *c_next(struct seq_file *m, void *v, loff_t *pos)
 173{
 174        ++*pos;
 175        return c_start(m, pos);
 176}
 177
 178static void c_stop(struct seq_file *m, void *v)
 179{
 180}
 181
 182extern int show_cpuinfo(struct seq_file *m, void *v);
 183
 184const struct seq_operations cpuinfo_op = {
 185        .start = c_start,
 186        .next  = c_next,
 187        .stop  = c_stop,
 188        .show  = show_cpuinfo,
 189};
 190
 191static int __init topology_init(void)
 192{
 193        int i;
 194
 195        for_each_possible_cpu(i) {
 196                 return register_cpu(&cpu_devices[i], i);
 197        }
 198
 199        return 0;
 200}
 201
 202subsys_initcall(topology_init);
 203
 204