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pgtable_64.c

/*
 *  This file contains ioremap and related functions for 64-bit machines.
 *
 *  Derived from arch/ppc64/mm/init.c
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *
 *  Modifications by Paul Mackerras (PowerMac) (paulus@samba.org)
 *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
 *    Copyright (C) 1996 Paul Mackerras
 *
 *  Derived from "arch/i386/mm/init.c"
 *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
 *
 *  Dave Engebretsen <engebret@us.ibm.com>
 *      Rework for PPC64 port.
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 *
 */

#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/stddef.h>
#include <linux/vmalloc.h>
#include <linux/init.h>

#include <asm/pgalloc.h>
#include <asm/page.h>
#include <asm/prom.h>
#include <asm/io.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/mmu.h>
#include <asm/smp.h>
#include <asm/machdep.h>
#include <asm/tlb.h>
#include <asm/processor.h>
#include <asm/cputable.h>
#include <asm/sections.h>
#include <asm/system.h>
#include <asm/abs_addr.h>
#include <asm/firmware.h>

#include "mmu_decl.h"

unsigned long ioremap_bot = IOREMAP_BASE;

/*
 * map_io_page currently only called by __ioremap
 * map_io_page adds an entry to the ioremap page table
 * and adds an entry to the HPT, possibly bolting it
 */
static int map_io_page(unsigned long ea, unsigned long pa, int flags)
{
      pgd_t *pgdp;
      pud_t *pudp;
      pmd_t *pmdp;
      pte_t *ptep;

      if (mem_init_done) {
            pgdp = pgd_offset_k(ea);
            pudp = pud_alloc(&init_mm, pgdp, ea);
            if (!pudp)
                  return -ENOMEM;
            pmdp = pmd_alloc(&init_mm, pudp, ea);
            if (!pmdp)
                  return -ENOMEM;
            ptep = pte_alloc_kernel(pmdp, ea);
            if (!ptep)
                  return -ENOMEM;
            set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT,
                                            __pgprot(flags)));
      } else {
            /*
             * If the mm subsystem is not fully up, we cannot create a
             * linux page table entry for this mapping.  Simply bolt an
             * entry in the hardware page table.
             *
             */
            if (htab_bolt_mapping(ea, ea + PAGE_SIZE, pa, flags,
                              mmu_io_psize, mmu_kernel_ssize)) {
                  printk(KERN_ERR "Failed to do bolted mapping IO "
                         "memory at %016lx !\n", pa);
                  return -ENOMEM;
            }
      }
      return 0;
}


/**
 * __ioremap_at - Low level function to establish the page tables
 *                for an IO mapping
 */
void __iomem * __ioremap_at(phys_addr_t pa, void *ea, unsigned long size,
                      unsigned long flags)
{
      unsigned long i;

      /* Make sure we have the base flags */
      if ((flags & _PAGE_PRESENT) == 0)
            flags |= pgprot_val(PAGE_KERNEL);

      /* Non-cacheable page cannot be coherent */
      if (flags & _PAGE_NO_CACHE)
            flags &= ~_PAGE_COHERENT;

      /* We don't support the 4K PFN hack with ioremap */
      if (flags & _PAGE_4K_PFN)
            return NULL;

      WARN_ON(pa & ~PAGE_MASK);
      WARN_ON(((unsigned long)ea) & ~PAGE_MASK);
      WARN_ON(size & ~PAGE_MASK);

      for (i = 0; i < size; i += PAGE_SIZE)
            if (map_io_page((unsigned long)ea+i, pa+i, flags))
                  return NULL;

      return (void __iomem *)ea;
}

/**
 * __iounmap_from - Low level function to tear down the page tables
 *                  for an IO mapping. This is used for mappings that
 *                  are manipulated manually, like partial unmapping of
 *                  PCI IOs or ISA space.
 */
void __iounmap_at(void *ea, unsigned long size)
{
      WARN_ON(((unsigned long)ea) & ~PAGE_MASK);
      WARN_ON(size & ~PAGE_MASK);

      unmap_kernel_range((unsigned long)ea, size);
}

void __iomem * __ioremap(phys_addr_t addr, unsigned long size,
                   unsigned long flags)
{
      phys_addr_t paligned;
      void __iomem *ret;

      /*
       * Choose an address to map it to.
       * Once the imalloc system is running, we use it.
       * Before that, we map using addresses going
       * up from ioremap_bot.  imalloc will use
       * the addresses from ioremap_bot through
       * IMALLOC_END
       * 
       */
      paligned = addr & PAGE_MASK;
      size = PAGE_ALIGN(addr + size) - paligned;

      if ((size == 0) || (paligned == 0))
            return NULL;

      if (mem_init_done) {
            struct vm_struct *area;

            area = __get_vm_area(size, VM_IOREMAP,
                             ioremap_bot, IOREMAP_END);
            if (area == NULL)
                  return NULL;
            ret = __ioremap_at(paligned, area->addr, size, flags);
            if (!ret)
                  vunmap(area->addr);
      } else {
            ret = __ioremap_at(paligned, (void *)ioremap_bot, size, flags);
            if (ret)
                  ioremap_bot += size;
      }

      if (ret)
            ret += addr & ~PAGE_MASK;
      return ret;
}


void __iomem * ioremap(phys_addr_t addr, unsigned long size)
{
      unsigned long flags = _PAGE_NO_CACHE | _PAGE_GUARDED;

      if (ppc_md.ioremap)
            return ppc_md.ioremap(addr, size, flags);
      return __ioremap(addr, size, flags);
}

void __iomem * ioremap_flags(phys_addr_t addr, unsigned long size,
                       unsigned long flags)
{
      /* writeable implies dirty for kernel addresses */
      if (flags & _PAGE_RW)
            flags |= _PAGE_DIRTY;

      /* we don't want to let _PAGE_USER and _PAGE_EXEC leak out */
      flags &= ~(_PAGE_USER | _PAGE_EXEC);

      if (ppc_md.ioremap)
            return ppc_md.ioremap(addr, size, flags);
      return __ioremap(addr, size, flags);
}


/*  
 * Unmap an IO region and remove it from imalloc'd list.
 * Access to IO memory should be serialized by driver.
 */
void __iounmap(volatile void __iomem *token)
{
      void *addr;

      if (!mem_init_done)
            return;
      
      addr = (void *) ((unsigned long __force)
                   PCI_FIX_ADDR(token) & PAGE_MASK);
      if ((unsigned long)addr < ioremap_bot) {
            printk(KERN_WARNING "Attempt to iounmap early bolted mapping"
                   " at 0x%p\n", addr);
            return;
      }
      vunmap(addr);
}

void iounmap(volatile void __iomem *token)
{
      if (ppc_md.iounmap)
            ppc_md.iounmap(token);
      else
            __iounmap(token);
}

EXPORT_SYMBOL(ioremap);
EXPORT_SYMBOL(ioremap_flags);
EXPORT_SYMBOL(__ioremap);
EXPORT_SYMBOL(__ioremap_at);
EXPORT_SYMBOL(iounmap);
EXPORT_SYMBOL(__iounmap);
EXPORT_SYMBOL(__iounmap_at);

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