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generic.c

/* $Id: generic.c,v 1.18 2001/12/21 04:56:15 davem Exp $
 * generic.c: Generic Sparc mm routines that are not dependent upon
 *            MMU type but are Sparc specific.
 *
 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
 */

#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/pagemap.h>

#include <asm/pgalloc.h>
#include <asm/pgtable.h>
#include <asm/page.h>
#include <asm/tlbflush.h>

/* Remap IO memory, the same way as remap_pfn_range(), but use
 * the obio memory space.
 *
 * They use a pgprot that sets PAGE_IO and does not check the
 * mem_map table as this is independent of normal memory.
 */
static inline void io_remap_pte_range(struct mm_struct *mm, pte_t * pte,
                              unsigned long address,
                              unsigned long size,
                              unsigned long offset, pgprot_t prot,
                              int space)
{
      unsigned long end;

      /* clear hack bit that was used as a write_combine side-effect flag */
      offset &= ~0x1UL;
      address &= ~PMD_MASK;
      end = address + size;
      if (end > PMD_SIZE)
            end = PMD_SIZE;
      do {
            pte_t entry;
            unsigned long curend = address + PAGE_SIZE;
            
            entry = mk_pte_io(offset, prot, space, PAGE_SIZE);
            if (!(address & 0xffff)) {
                  if (PAGE_SIZE < (4 * 1024 * 1024) &&
                      !(address & 0x3fffff) &&
                      !(offset & 0x3ffffe) &&
                      end >= address + 0x400000) {
                        entry = mk_pte_io(offset, prot, space,
                                      4 * 1024 * 1024);
                        curend = address + 0x400000;
                        offset += 0x400000;
                  } else if (PAGE_SIZE < (512 * 1024) &&
                           !(address & 0x7ffff) &&
                           !(offset & 0x7fffe) &&
                           end >= address + 0x80000) {
                        entry = mk_pte_io(offset, prot, space,
                                      512 * 1024 * 1024);
                        curend = address + 0x80000;
                        offset += 0x80000;
                  } else if (PAGE_SIZE < (64 * 1024) &&
                           !(offset & 0xfffe) &&
                           end >= address + 0x10000) {
                        entry = mk_pte_io(offset, prot, space,
                                      64 * 1024);
                        curend = address + 0x10000;
                        offset += 0x10000;
                  } else
                        offset += PAGE_SIZE;
            } else
                  offset += PAGE_SIZE;

            if (pte_write(entry))
                  entry = pte_mkdirty(entry);
            do {
                  BUG_ON(!pte_none(*pte));
                  set_pte_at(mm, address, pte, entry);
                  address += PAGE_SIZE;
                  pte_val(entry) += PAGE_SIZE;
                  pte++;
            } while (address < curend);
      } while (address < end);
}

static inline int io_remap_pmd_range(struct mm_struct *mm, pmd_t * pmd, unsigned long address, unsigned long size,
      unsigned long offset, pgprot_t prot, int space)
{
      unsigned long end;

      address &= ~PGDIR_MASK;
      end = address + size;
      if (end > PGDIR_SIZE)
            end = PGDIR_SIZE;
      offset -= address;
      do {
            pte_t * pte = pte_alloc_map(mm, pmd, address);
            if (!pte)
                  return -ENOMEM;
            io_remap_pte_range(mm, pte, address, end - address, address + offset, prot, space);
            pte_unmap(pte);
            address = (address + PMD_SIZE) & PMD_MASK;
            pmd++;
      } while (address < end);
      return 0;
}

static inline int io_remap_pud_range(struct mm_struct *mm, pud_t * pud, unsigned long address, unsigned long size,
      unsigned long offset, pgprot_t prot, int space)
{
      unsigned long end;

      address &= ~PUD_MASK;
      end = address + size;
      if (end > PUD_SIZE)
            end = PUD_SIZE;
      offset -= address;
      do {
            pmd_t *pmd = pmd_alloc(mm, pud, address);
            if (!pud)
                  return -ENOMEM;
            io_remap_pmd_range(mm, pmd, address, end - address, address + offset, prot, space);
            address = (address + PUD_SIZE) & PUD_MASK;
            pud++;
      } while (address < end);
      return 0;
}

int io_remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
            unsigned long pfn, unsigned long size, pgprot_t prot)
{
      int error = 0;
      pgd_t * dir;
      unsigned long beg = from;
      unsigned long end = from + size;
      struct mm_struct *mm = vma->vm_mm;
      int space = GET_IOSPACE(pfn);
      unsigned long offset = GET_PFN(pfn) << PAGE_SHIFT;
      unsigned long phys_base;

      phys_base = offset | (((unsigned long) space) << 32UL);

      /* See comment in mm/memory.c remap_pfn_range */
      vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
      vma->vm_pgoff = phys_base >> PAGE_SHIFT;

      offset -= from;
      dir = pgd_offset(mm, from);
      flush_cache_range(vma, beg, end);

      while (from < end) {
            pud_t *pud = pud_alloc(mm, dir, from);
            error = -ENOMEM;
            if (!pud)
                  break;
            error = io_remap_pud_range(mm, pud, from, end - from, offset + from, prot, space);
            if (error)
                  break;
            from = (from + PGDIR_SIZE) & PGDIR_MASK;
            dir++;
      }

      flush_tlb_range(vma, beg, end);
      return error;
}

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