arch/s390x/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 <asm/io.h>
  18 #include <asm/pgalloc.h>
  19
  20 static inline void remap_area_pte(pte_t * pte, unsigned long address, unsigned long size,
  21         unsigned long phys_addr, unsigned long flags)
  22 {
  23         unsigned long end;
  24
  25         address &= ~PMD_MASK;
  26         end = address + size;
  27         if (end > PMD_SIZE)
  28                 end = PMD_SIZE;
  29         if (address >= end)
  30                 BUG();
  31         do {
  32                 if (!pte_none(*pte)) {
  33                         printk("remap_area_pte: page already exists\n");
  34                         BUG();
  35                 }
  36                 set_pte(pte, mk_pte_phys(phys_addr,
  37                                          __pgprot(_PAGE_PRESENT | flags)));
  38                 address += PAGE_SIZE;
  39                 phys_addr += PAGE_SIZE;
  40                 pte++;
  41         } while (address && (address < end));
  42 }
  43
  44 static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size,
  45         unsigned long phys_addr, unsigned long flags)
  46 {
  47         unsigned long end;
  48
  49         address &= ~PGDIR_MASK;
  50         end = address + size;
  51         if (end > PGDIR_SIZE)
  52                 end = PGDIR_SIZE;
  53         phys_addr -= address;
  54         if (address >= end)
  55                 BUG();
  56         do {
  57                 pte_t * pte = pte_alloc(&init_mm, pmd, address);
  58                 if (!pte)
  59                         return -ENOMEM;
  60                 remap_area_pte(pte, address, end - address, address + phys_addr, flags);
  61                 address = (address + PMD_SIZE) & PMD_MASK;
  62                 pmd++;
  63         } while (address && (address < end));
  64         return 0;
  65 }
  66
  67 static int remap_area_pages(unsigned long address, unsigned long phys_addr,
  68                                  unsigned long size, unsigned long flags)
  69 {
  70         int error;
  71         pgd_t * dir;
  72         unsigned long end = address + size;
  73
  74         phys_addr -= address;
  75         dir = pgd_offset(&init_mm, address);
  76         flush_cache_all();
  77         if (address >= end)
  78                 BUG();
  79         spin_lock(&init_mm.page_table_lock);
  80         do {
  81                 pmd_t *pmd;
  82                 pmd = pmd_alloc(&init_mm, dir, address);
  83                 error = -ENOMEM;
  84                 if (!pmd)
  85                         break;
  86                 if (remap_area_pmd(pmd, address, end - address,
  87                                          phys_addr + address, flags))
  88                         break;
  89                 error = 0;
  90                 address = (address + PGDIR_SIZE) & PGDIR_MASK;
  91                 dir++;
  92         } while (address && (address < end));
  93         spin_unlock(&init_mm.page_table_lock);
  94         flush_tlb_all();
  95         return 0;
  96 }
  97
  98 /*
  99  * Generic mapping function (not visible outside):
 100  */
 101
 102 /*
 103  * Remap an arbitrary physical address space into the kernel virtual
 104  * address space. Needed when the kernel wants to access high addresses
 105  * directly.
 106  */
 107 void * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags)
 108 {
 109         void * addr;
 110         struct vm_struct * area;
 111
 112         if (phys_addr < virt_to_phys(high_memory))
 113                 return phys_to_virt(phys_addr);
 114         if (phys_addr & ~PAGE_MASK)
 115                 return NULL;
 116         size = PAGE_ALIGN(size);
 117         if (!size || size > phys_addr + size)
 118                 return NULL;
 119         area = get_vm_area(size, VM_IOREMAP);
 120         if (!area)
 121                 return NULL;
 122         addr = area->addr;
 123         if (remap_area_pages(VMALLOC_VMADDR(addr), phys_addr, size, flags)) {
 124                 vfree(addr);
 125                 return NULL;
 126         }
 127         return addr;
 128 }
 129
 130 void iounmap(void *addr)
 131 {
 132         if (addr > high_memory)
 133                 return vfree(addr);
 134 }