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/config.h>
  14 #include <linux/init.h>
  15 #include <linux/mm.h>
  16 #include <linux/bootmem.h>
  17 #include <asm/pgtable.h>
  18 #include <linux/seq_file.h>
  19 #include <linux/tty.h>
  20
  21 #include <asm/setup.h>
  22
  23 /*
  24  * Setup options
  25  */
  26 struct drive_info_struct { char dummy[32]; } drive_info;
  27 struct screen_info screen_info;
  28
  29 unsigned char aux_device_present;
  30
  31 extern int root_mountflags;
  32 extern char _etext, _edata, _end;
  33
  34 static char command_line[COMMAND_LINE_SIZE] = { 0, };
  35
  36 extern const unsigned long text_start, edata; /* set by the linker script */
  37 extern unsigned long dram_start, dram_end;
  38
  39 extern unsigned long romfs_start, romfs_length, romfs_in_flash; /* from head.S */
  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
  60 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 #define PFN_UP(x)       (((x) + PAGE_SIZE-1) >> PAGE_SHIFT)
  94 #define PFN_DOWN(x)     ((x) >> PAGE_SHIFT)
  95 #define PFN_PHYS(x)     ((x) << PAGE_SHIFT)
  96
  97         /* min_low_pfn points to the start of DRAM, start_pfn points
  98          * to the first DRAM pages after the kernel, and max_low_pfn
  99          * to the end of DRAM.
 100          */
 101
 102         /*
 103          * partially used pages are not usable - thus
 104          * we are rounding upwards:
 105          */
 106
 107         start_pfn = PFN_UP(memory_start);  /* usually c0000000 + kernel + romfs */
 108         max_pfn =   PFN_DOWN((unsigned long)high_memory); /* usually c0000000 + dram size */
 109
 110         /*
 111          * Initialize the boot-time allocator (start, end)
 112          *
 113          * We give it access to all our DRAM, but we could as well just have
 114          * given it a small slice. No point in doing that though, unless we
 115          * have non-contiguous memory and want the boot-stuff to be in, say,
 116          * the smallest area.
 117          *
 118          * It will put a bitmap of the allocated pages in the beginning
 119          * of the range we give it, but it won't mark the bitmaps pages
 120          * as reserved. We have to do that ourselves below.
 121          *
 122          * We need to use init_bootmem_node instead of init_bootmem
 123          * because our map starts at a quite high address (min_low_pfn).
 124          */
 125
 126         max_low_pfn = max_pfn;
 127         min_low_pfn = PAGE_OFFSET >> PAGE_SHIFT;
 128
 129         bootmap_size = init_bootmem_node(NODE_DATA(0), start_pfn,
 130                                          min_low_pfn,
 131                                          max_low_pfn);
 132
 133         /* And free all memory not belonging to the kernel (addr, size) */
 134
 135         free_bootmem(PFN_PHYS(start_pfn), PFN_PHYS(max_pfn - start_pfn));
 136
 137         /*
 138          * Reserve the bootmem bitmap itself as well. We do this in two
 139          * steps (first step was init_bootmem()) because this catches
 140          * the (very unlikely) case of us accidentally initializing the
 141          * bootmem allocator with an invalid RAM area.
 142          *
 143          * Arguments are start, size
 144          */
 145
 146         reserve_bootmem(PFN_PHYS(start_pfn), bootmap_size);
 147
 148         /* paging_init() sets up the MMU and marks all pages as reserved */
 149
 150         paging_init();
 151
 152         /* We don't use a command line yet, so just re-initialize it without
 153            saving anything that might be there.  */
 154
 155         *cmdline_p = command_line;
 156
 157 #ifdef CONFIG_ETRAX_CMDLINE
 158         strlcpy(command_line, CONFIG_ETRAX_CMDLINE, COMMAND_LINE_SIZE);
 159         command_line[COMMAND_LINE_SIZE - 1] = '\0';
 160
 161         /* Save command line for future references. */
 162         memcpy(saved_command_line, command_line, COMMAND_LINE_SIZE);
 163         saved_command_line[COMMAND_LINE_SIZE - 1] = '\0';
 164 #endif
 165
 166         /* give credit for the CRIS port */
 167         show_etrax_copyright();
 168 }
 169
 170 static void *c_start(struct seq_file *m, loff_t *pos)
 171 {
 172         /* We only got one CPU... */
 173         return *pos < 1 ? (void *)1 : NULL;
 174 }
 175
 176 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
 177 {
 178         ++*pos;
 179         return NULL;
 180 }
 181
 182 static void c_stop(struct seq_file *m, void *v)
 183 {
 184 }
 185
 186 extern int show_cpuinfo(struct seq_file *m, void *v);
 187
 188 struct seq_operations cpuinfo_op = {
 189         .start = c_start,
 190         .next  = c_next,
 191         .stop  = c_stop,
 192         .show  = show_cpuinfo,
 193 };
 194
 195