arch/powerpc/mm/pgtable_64.c

   1 /*
   2  *  This file contains ioremap and related functions for 64-bit machines.
   3  *
   4  *  Derived from arch/ppc64/mm/init.c
   5  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
   6  *
   7  *  Modifications by Paul Mackerras (PowerMac) (paulus@samba.org)
   8  *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
   9  *    Copyright (C) 1996 Paul Mackerras
  10  *
  11  *  Derived from "arch/i386/mm/init.c"
  12  *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
  13  *
  14  *  Dave Engebretsen <engebret@us.ibm.com>
  15  *      Rework for PPC64 port.
  16  *
  17  *  This program is free software; you can redistribute it and/or
  18  *  modify it under the terms of the GNU General Public License
  19  *  as published by the Free Software Foundation; either version
  20  *  2 of the License, or (at your option) any later version.
  21  *
  22  */
  23
  24 #include <linux/signal.h>
  25 #include <linux/sched.h>
  26 #include <linux/kernel.h>
  27 #include <linux/errno.h>
  28 #include <linux/string.h>
  29 #include <linux/types.h>
  30 #include <linux/mman.h>
  31 #include <linux/mm.h>
  32 #include <linux/swap.h>
  33 #include <linux/stddef.h>
  34 #include <linux/vmalloc.h>
  35 #include <linux/init.h>
  36
  37 #include <asm/pgalloc.h>
  38 #include <asm/page.h>
  39 #include <asm/prom.h>
  40 #include <asm/io.h>
  41 #include <asm/mmu_context.h>
  42 #include <asm/pgtable.h>
  43 #include <asm/mmu.h>
  44 #include <asm/smp.h>
  45 #include <asm/machdep.h>
  46 #include <asm/tlb.h>
  47 #include <asm/processor.h>
  48 #include <asm/cputable.h>
  49 #include <asm/sections.h>
  50 #include <asm/system.h>
  51 #include <asm/abs_addr.h>
  52 #include <asm/firmware.h>
  53
  54 #include "mmu_decl.h"
  55
  56 unsigned long ioremap_bot = IOREMAP_BASE;
  57
  58 /*
  59  * map_io_page currently only called by __ioremap
  60  * map_io_page adds an entry to the ioremap page table
  61  * and adds an entry to the HPT, possibly bolting it
  62  */
  63 static int map_io_page(unsigned long ea, unsigned long pa, int flags)
  64 {
  65         pgd_t *pgdp;
  66         pud_t *pudp;
  67         pmd_t *pmdp;
  68         pte_t *ptep;
  69
  70         if (mem_init_done) {
  71                 pgdp = pgd_offset_k(ea);
  72                 pudp = pud_alloc(&init_mm, pgdp, ea);
  73                 if (!pudp)
  74                         return -ENOMEM;
  75                 pmdp = pmd_alloc(&init_mm, pudp, ea);
  76                 if (!pmdp)
  77                         return -ENOMEM;
  78                 ptep = pte_alloc_kernel(pmdp, ea);
  79                 if (!ptep)
  80                         return -ENOMEM;
  81                 set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT,
  82                                                           __pgprot(flags)));
  83         } else {
  84                 /*
  85                  * If the mm subsystem is not fully up, we cannot create a
  86                  * linux page table entry for this mapping.  Simply bolt an
  87                  * entry in the hardware page table.
  88                  *
  89                  */
  90                 if (htab_bolt_mapping(ea, ea + PAGE_SIZE, pa, flags,
  91                                       mmu_io_psize, mmu_kernel_ssize)) {
  92                         printk(KERN_ERR "Failed to do bolted mapping IO "
  93                                "memory at %016lx !\n", pa);
  94                         return -ENOMEM;
  95                 }
  96         }
  97         return 0;
  98 }
  99
 100
 101 /**
 102  * __ioremap_at - Low level function to establish the page tables
 103  *                for an IO mapping
 104  */
 105 void __iomem * __ioremap_at(phys_addr_t pa, void *ea, unsigned long size,
 106                             unsigned long flags)
 107 {
 108         unsigned long i;
 109
 110         if ((flags & _PAGE_PRESENT) == 0)
 111                 flags |= pgprot_val(PAGE_KERNEL);
 112
 113         WARN_ON(pa & ~PAGE_MASK);
 114         WARN_ON(((unsigned long)ea) & ~PAGE_MASK);
 115         WARN_ON(size & ~PAGE_MASK);
 116
 117         for (i = 0; i < size; i += PAGE_SIZE)
 118                 if (map_io_page((unsigned long)ea+i, pa+i, flags))
 119                         return NULL;
 120
 121         return (void __iomem *)ea;
 122 }
 123
 124 /**
 125  * __iounmap_from - Low level function to tear down the page tables
 126  *                  for an IO mapping. This is used for mappings that
 127  *                  are manipulated manually, like partial unmapping of
 128  *                  PCI IOs or ISA space.
 129  */
 130 void __iounmap_at(void *ea, unsigned long size)
 131 {
 132         WARN_ON(((unsigned long)ea) & ~PAGE_MASK);
 133         WARN_ON(size & ~PAGE_MASK);
 134
 135         unmap_kernel_range((unsigned long)ea, size);
 136 }
 137
 138 void __iomem * __ioremap(phys_addr_t addr, unsigned long size,
 139                          unsigned long flags)
 140 {
 141         phys_addr_t paligned;
 142         void __iomem *ret;
 143
 144         /*
 145          * Choose an address to map it to.
 146          * Once the imalloc system is running, we use it.
 147          * Before that, we map using addresses going
 148          * up from ioremap_bot.  imalloc will use
 149          * the addresses from ioremap_bot through
 150          * IMALLOC_END
 151          *
 152          */
 153         paligned = addr & PAGE_MASK;
 154         size = PAGE_ALIGN(addr + size) - paligned;
 155
 156         if ((size == 0) || (paligned == 0))
 157                 return NULL;
 158
 159         if (mem_init_done) {
 160                 struct vm_struct *area;
 161
 162                 area = __get_vm_area(size, VM_IOREMAP,
 163                                      ioremap_bot, IOREMAP_END);
 164                 if (area == NULL)
 165                         return NULL;
 166                 ret = __ioremap_at(paligned, area->addr, size, flags);
 167                 if (!ret)
 168                         vunmap(area->addr);
 169         } else {
 170                 ret = __ioremap_at(paligned, (void *)ioremap_bot, size, flags);
 171                 if (ret)
 172                         ioremap_bot += size;
 173         }
 174
 175         if (ret)
 176                 ret += addr & ~PAGE_MASK;
 177         return ret;
 178 }
 179
 180
 181 void __iomem * ioremap(phys_addr_t addr, unsigned long size)
 182 {
 183         unsigned long flags = _PAGE_NO_CACHE | _PAGE_GUARDED;
 184
 185         if (ppc_md.ioremap)
 186                 return ppc_md.ioremap(addr, size, flags);
 187         return __ioremap(addr, size, flags);
 188 }
 189
 190 void __iomem * ioremap_flags(phys_addr_t addr, unsigned long size,
 191                              unsigned long flags)
 192 {
 193         if (ppc_md.ioremap)
 194                 return ppc_md.ioremap(addr, size, flags);
 195         return __ioremap(addr, size, flags);
 196 }
 197
 198
 199 /*
 200  * Unmap an IO region and remove it from imalloc'd list.
 201  * Access to IO memory should be serialized by driver.
 202  */
 203 void __iounmap(volatile void __iomem *token)
 204 {
 205         void *addr;
 206
 207         if (!mem_init_done)
 208                 return;
 209
 210         addr = (void *) ((unsigned long __force)
 211                          PCI_FIX_ADDR(token) & PAGE_MASK);
 212         if ((unsigned long)addr < ioremap_bot) {
 213                 printk(KERN_WARNING "Attempt to iounmap early bolted mapping"
 214                        " at 0x%p\n", addr);
 215                 return;
 216         }
 217         vunmap(addr);
 218 }
 219
 220 void iounmap(volatile void __iomem *token)
 221 {
 222         if (ppc_md.iounmap)
 223                 ppc_md.iounmap(token);
 224         else
 225                 __iounmap(token);
 226 }
 227
 228 EXPORT_SYMBOL(ioremap);
 229 EXPORT_SYMBOL(ioremap_flags);
 230 EXPORT_SYMBOL(__ioremap);
 231 EXPORT_SYMBOL(__ioremap_at);
 232 EXPORT_SYMBOL(iounmap);
 233 EXPORT_SYMBOL(__iounmap);
 234 EXPORT_SYMBOL(__iounmap_at);