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
  24 /*
  25  * Setup options
  26  */
  27 struct screen_info screen_info;
  28
  29 extern int root_mountflags;
  30 extern char _etext, _edata, _end;
  31
  32 char __initdata cris_command_line[COMMAND_LINE_SIZE] = { 0, };
  33
  34 extern const unsigned long text_start, edata; /* set by the linker script */
  35 extern unsigned long dram_start, dram_end;
  36
  37 extern unsigned long romfs_start, romfs_length, romfs_in_flash; /* from head.S */
  38
  39 static struct cpu cpu_devices[NR_CPUS];
  40
  41 extern 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
  59 void __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
 167 static void *c_start(struct seq_file *m, loff_t *pos)
 168 {
 169         return *pos < nr_cpu_ids ? (void *)(int)(*pos + 1) : NULL;
 170 }
 171
 172 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
 173 {
 174         ++*pos;
 175         return c_start(m, pos);
 176 }
 177
 178 static void c_stop(struct seq_file *m, void *v)
 179 {
 180 }
 181
 182 extern int show_cpuinfo(struct seq_file *m, void *v);
 183
 184 const struct seq_operations cpuinfo_op = {
 185         .start = c_start,
 186         .next  = c_next,
 187         .stop  = c_stop,
 188         .show  = show_cpuinfo,
 189 };
 190
 191 static 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
 202 subsys_initcall(topology_init);
 203