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 <linux/of.h>
  23 #include <linux/of_fdt.h>
  24 #include <asm/setup.h>
  25 #include <arch/system.h>
  26
  27 /*
  28  * Setup options
  29  */
  30 struct screen_info screen_info;
  31
  32 extern int root_mountflags;
  33 extern char _etext, _edata, _end;
  34
  35 char __initdata cris_command_line[COMMAND_LINE_SIZE] = { 0, };
  36
  37 extern const unsigned long text_start, edata; /* set by the linker script */
  38 extern unsigned long dram_start, dram_end;
  39
  40 extern unsigned long romfs_start, romfs_length, romfs_in_flash; /* from head.S */
  41
  42 static struct cpu cpu_devices[NR_CPUS];
  43
  44 extern void show_etrax_copyright(void);         /* arch-vX/kernel/setup.c */
  45
  46 /* This mainly sets up the memory area, and can be really confusing.
  47  *
  48  * The physical DRAM is virtually mapped into dram_start to dram_end
  49  * (usually c0000000 to c0000000 + DRAM size). The physical address is
  50  * given by the macro __pa().
  51  *
  52  * In this DRAM, the kernel code and data is loaded, in the beginning.
  53  * It really starts at c0004000 to make room for some special pages -
  54  * the start address is text_start. The kernel data ends at _end. After
  55  * this the ROM filesystem is appended (if there is any).
  56  *
  57  * Between this address and dram_end, we have RAM pages usable to the
  58  * boot code and the system.
  59  *
  60  */
  61
  62 void __init setup_arch(char **cmdline_p)
  63 {
  64         extern void init_etrax_debug(void);
  65         unsigned long bootmap_size;
  66         unsigned long start_pfn, max_pfn;
  67         unsigned long memory_start;
  68
  69 #ifdef CONFIG_OF
  70         early_init_dt_scan(__dtb_start);
  71 #endif
  72
  73         /* register an initial console printing routine for printk's */
  74
  75         init_etrax_debug();
  76
  77         /* we should really poll for DRAM size! */
  78
  79         high_memory = &dram_end;
  80
  81         if(romfs_in_flash || !romfs_length) {
  82                 /* if we have the romfs in flash, or if there is no rom filesystem,
  83                  * our free area starts directly after the BSS
  84                  */
  85                 memory_start = (unsigned long) &_end;
  86         } else {
  87                 /* otherwise the free area starts after the ROM filesystem */
  88                 printk("ROM fs in RAM, size %lu bytes\n", romfs_length);
  89                 memory_start = romfs_start + romfs_length;
  90         }
  91
  92         /* process 1's initial memory region is the kernel code/data */
  93
  94         init_mm.start_code = (unsigned long) &text_start;
  95         init_mm.end_code =   (unsigned long) &_etext;
  96         init_mm.end_data =   (unsigned long) &_edata;
  97         init_mm.brk =        (unsigned long) &_end;
  98
  99         /* min_low_pfn points to the start of DRAM, start_pfn points
 100          * to the first DRAM pages after the kernel, and max_low_pfn
 101          * to the end of DRAM.
 102          */
 103
 104         /*
 105          * partially used pages are not usable - thus
 106          * we are rounding upwards:
 107          */
 108
 109         start_pfn = PFN_UP(memory_start);  /* usually c0000000 + kernel + romfs */
 110         max_pfn =   PFN_DOWN((unsigned long)high_memory); /* usually c0000000 + dram size */
 111
 112         /*
 113          * Initialize the boot-time allocator (start, end)
 114          *
 115          * We give it access to all our DRAM, but we could as well just have
 116          * given it a small slice. No point in doing that though, unless we
 117          * have non-contiguous memory and want the boot-stuff to be in, say,
 118          * the smallest area.
 119          *
 120          * It will put a bitmap of the allocated pages in the beginning
 121          * of the range we give it, but it won't mark the bitmaps pages
 122          * as reserved. We have to do that ourselves below.
 123          *
 124          * We need to use init_bootmem_node instead of init_bootmem
 125          * because our map starts at a quite high address (min_low_pfn).
 126          */
 127
 128         max_low_pfn = max_pfn;
 129         min_low_pfn = PAGE_OFFSET >> PAGE_SHIFT;
 130
 131         bootmap_size = init_bootmem_node(NODE_DATA(0), start_pfn,
 132                                          min_low_pfn,
 133                                          max_low_pfn);
 134
 135         /* And free all memory not belonging to the kernel (addr, size) */
 136
 137         free_bootmem(PFN_PHYS(start_pfn), PFN_PHYS(max_pfn - start_pfn));
 138
 139         /*
 140          * Reserve the bootmem bitmap itself as well. We do this in two
 141          * steps (first step was init_bootmem()) because this catches
 142          * the (very unlikely) case of us accidentally initializing the
 143          * bootmem allocator with an invalid RAM area.
 144          *
 145          * Arguments are start, size
 146          */
 147
 148         reserve_bootmem(PFN_PHYS(start_pfn), bootmap_size, BOOTMEM_DEFAULT);
 149
 150         unflatten_and_copy_device_tree();
 151
 152         /* paging_init() sets up the MMU and marks all pages as reserved */
 153
 154         paging_init();
 155
 156         *cmdline_p = cris_command_line;
 157
 158 #ifdef CONFIG_ETRAX_CMDLINE
 159         if (!strcmp(cris_command_line, "")) {
 160                 strlcpy(cris_command_line, CONFIG_ETRAX_CMDLINE, COMMAND_LINE_SIZE);
 161                 cris_command_line[COMMAND_LINE_SIZE - 1] = '\0';
 162         }
 163 #endif
 164
 165         /* Save command line for future references. */
 166         memcpy(boot_command_line, cris_command_line, COMMAND_LINE_SIZE);
 167         boot_command_line[COMMAND_LINE_SIZE - 1] = '\0';
 168
 169         /* give credit for the CRIS port */
 170         show_etrax_copyright();
 171
 172         /* Setup utsname */
 173         strcpy(init_utsname()->machine, cris_machine_name);
 174 }
 175
 176 #ifdef CONFIG_PROC_FS
 177 static void *c_start(struct seq_file *m, loff_t *pos)
 178 {
 179         return *pos < nr_cpu_ids ? (void *)(int)(*pos + 1) : NULL;
 180 }
 181
 182 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
 183 {
 184         ++*pos;
 185         return c_start(m, pos);
 186 }
 187
 188 static void c_stop(struct seq_file *m, void *v)
 189 {
 190 }
 191
 192 extern int show_cpuinfo(struct seq_file *m, void *v);
 193
 194 const struct seq_operations cpuinfo_op = {
 195         .start = c_start,
 196         .next  = c_next,
 197         .stop  = c_stop,
 198         .show  = show_cpuinfo,
 199 };
 200 #endif /* CONFIG_PROC_FS */
 201
 202 static int __init topology_init(void)
 203 {
 204         int i;
 205
 206         for_each_possible_cpu(i) {
 207                  return register_cpu(&cpu_devices[i], i);
 208         }
 209
 210         return 0;
 211 }
 212
 213 subsys_initcall(topology_init);