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