arch/cris/kernel/setup.c

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