arch/s390/mm/ioremap.c

   1 /*
   2  *  arch/s390/mm/ioremap.c
   3  *
   4  *  S390 version
   5  *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
   6  *    Author(s): Hartmut Penner (hp@de.ibm.com)
   7  *
   8  *  Derived from "arch/i386/mm/extable.c"
   9  *    (C) Copyright 1995 1996 Linus Torvalds
  10  *
  11  * Re-map IO memory to kernel address space so that we can access it.
  12  * This is needed for high PCI addresses that aren't mapped in the
  13  * 640k-1MB IO memory area on PC's
  14  */
  15
  16 #include <linux/vmalloc.h>
  17 #include <linux/mm.h>
  18 #include <asm/io.h>
  19 #include <asm/pgalloc.h>
  20 #include <asm/cacheflush.h>
  21 #include <asm/tlbflush.h>
  22
  23 static inline void remap_area_pte(pte_t * pte, unsigned long address, unsigned long size,
  24         unsigned long phys_addr, unsigned long flags)
  25 {
  26         unsigned long end;
  27         unsigned long pfn;
  28
  29         address &= ~PMD_MASK;
  30         end = address + size;
  31         if (end > PMD_SIZE)
  32                 end = PMD_SIZE;
  33         if (address >= end)
  34                 BUG();
  35         pfn = phys_addr >> PAGE_SHIFT;
  36         do {
  37                 if (!pte_none(*pte)) {
  38                         printk("remap_area_pte: page already exists\n");
  39                         BUG();
  40                 }
  41                 set_pte(pte, pfn_pte(pfn, __pgprot(flags)));
  42                 address += PAGE_SIZE;
  43                 pfn++;
  44                 pte++;
  45         } while (address && (address < end));
  46 }
  47
  48 static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size,
  49         unsigned long phys_addr, unsigned long flags)
  50 {
  51         unsigned long end;
  52
  53         address &= ~PGDIR_MASK;
  54         end = address + size;
  55         if (end > PGDIR_SIZE)
  56                 end = PGDIR_SIZE;
  57         phys_addr -= address;
  58         if (address >= end)
  59                 BUG();
  60         do {
  61                 pte_t * pte = pte_alloc_kernel(&init_mm, pmd, address);
  62                 if (!pte)
  63                         return -ENOMEM;
  64                 remap_area_pte(pte, address, end - address, address + phys_addr, flags);
  65                 address = (address + PMD_SIZE) & PMD_MASK;
  66                 pmd++;
  67         } while (address && (address < end));
  68         return 0;
  69 }
  70
  71 static int remap_area_pages(unsigned long address, unsigned long phys_addr,
  72                                  unsigned long size, unsigned long flags)
  73 {
  74         int error;
  75         pgd_t * dir;
  76         unsigned long end = address + size;
  77
  78         phys_addr -= address;
  79         dir = pgd_offset(&init_mm, address);
  80         flush_cache_all();
  81         if (address >= end)
  82                 BUG();
  83         spin_lock(&init_mm.page_table_lock);
  84         do {
  85                 pmd_t *pmd;
  86                 pmd = pmd_alloc(&init_mm, dir, address);
  87                 error = -ENOMEM;
  88                 if (!pmd)
  89                         break;
  90                 if (remap_area_pmd(pmd, address, end - address,
  91                                          phys_addr + address, flags))
  92                         break;
  93                 error = 0;
  94                 address = (address + PGDIR_SIZE) & PGDIR_MASK;
  95                 dir++;
  96         } while (address && (address < end));
  97         spin_unlock(&init_mm.page_table_lock);
  98         flush_tlb_all();
  99         return 0;
 100 }
 101
 102 /*
 103  * Generic mapping function (not visible outside):
 104  */
 105
 106 /*
 107  * Remap an arbitrary physical address space into the kernel virtual
 108  * address space. Needed when the kernel wants to access high addresses
 109  * directly.
 110  */
 111 void * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags)
 112 {
 113         void * addr;
 114         struct vm_struct * area;
 115
 116         if (phys_addr < virt_to_phys(high_memory))
 117                 return phys_to_virt(phys_addr);
 118         if (phys_addr & ~PAGE_MASK)
 119                 return NULL;
 120         size = PAGE_ALIGN(size);
 121         if (!size || size > phys_addr + size)
 122                 return NULL;
 123         area = get_vm_area(size, VM_IOREMAP);
 124         if (!area)
 125                 return NULL;
 126         addr = area->addr;
 127         if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) {
 128                 vfree(addr);
 129                 return NULL;
 130         }
 131         return addr;
 132 }
 133
 134 void iounmap(void *addr)
 135 {
 136         if (addr > high_memory)
 137                 vfree(addr);
 138 }