arch/arm/mm/nommu.c

   1 /*
   2  *  linux/arch/arm/mm/nommu.c
   3  *
   4  * ARM uCLinux supporting functions.
   5  */
   6 #include <linux/module.h>
   7 #include <linux/mm.h>
   8 #include <linux/pagemap.h>
   9
  10 #include <asm/cacheflush.h>
  11 #include <asm/io.h>
  12 #include <asm/page.h>
  13
  14 #include "mm.h"
  15
  16 extern void _stext, __data_start, _end;
  17
  18 /*
  19  * Reserve the various regions of node 0
  20  */
  21 void __init reserve_node_zero(pg_data_t *pgdat)
  22 {
  23         /*
  24          * Register the kernel text and data with bootmem.
  25          * Note that this can only be in node 0.
  26          */
  27 #ifdef CONFIG_XIP_KERNEL
  28         reserve_bootmem_node(pgdat, __pa(&__data_start), &_end - &__data_start);
  29 #else
  30         reserve_bootmem_node(pgdat, __pa(&_stext), &_end - &_stext);
  31 #endif
  32
  33         /*
  34          * Register the exception vector page.
  35          * some architectures which the DRAM is the exception vector to trap,
  36          * alloc_page breaks with error, although it is not NULL, but "0."
  37          */
  38         reserve_bootmem_node(pgdat, CONFIG_VECTORS_BASE, PAGE_SIZE);
  39 }
  40
  41 /*
  42  * paging_init() sets up the page tables, initialises the zone memory
  43  * maps, and sets up the zero page, bad page and bad page tables.
  44  */
  45 void __init paging_init(struct meminfo *mi, struct machine_desc *mdesc)
  46 {
  47         bootmem_init(mi);
  48 }
  49
  50 /*
  51  * We don't need to do anything here for nommu machines.
  52  */
  53 void setup_mm_for_reboot(char mode)
  54 {
  55 }
  56
  57 void flush_dcache_page(struct page *page)
  58 {
  59         __cpuc_flush_dcache_page(page_address(page));
  60 }
  61 EXPORT_SYMBOL(flush_dcache_page);
  62
  63 void __iomem *__ioremap_pfn(unsigned long pfn, unsigned long offset,
  64                             size_t size, unsigned long flags)
  65 {
  66         if (pfn >= (0x100000000ULL >> PAGE_SHIFT))
  67                 return NULL;
  68         return (void __iomem *) (offset + (pfn << PAGE_SHIFT));
  69 }
  70 EXPORT_SYMBOL(__ioremap_pfn);
  71
  72 void __iomem *__ioremap(unsigned long phys_addr, size_t size,
  73                         unsigned long flags)
  74 {
  75         return (void __iomem *)phys_addr;
  76 }
  77 EXPORT_SYMBOL(__ioremap);
  78
  79 void __iounmap(volatile void __iomem *addr)
  80 {
  81 }
  82 EXPORT_SYMBOL(__iounmap);
  83
  84 /*
  85  * You really shouldn't be using read() or write() on /dev/mem.  This
  86  * might go away in the future.
  87  */
  88 int valid_phys_addr_range(unsigned long addr, size_t size)
  89 {
  90         if (addr + size > __pa(high_memory))
  91                 return 0;
  92
  93         return 1;
  94 }
  95
  96 /*
  97  * We don't use supersection mappings for mmap() on /dev/mem, which
  98  * means that we can't map the memory area above the 4G barrier into
  99  * userspace.
 100  */
 101 int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
 102 {
 103         return !(pfn + (size >> PAGE_SHIFT) > 0x00100000);
 104 }