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