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kmap.c

/*
 *  linux/arch/m68k/mm/kmap.c
 *
 *  Copyright (C) 1997 Roman Hodek
 *
 *  10/01/99 cleaned up the code and changing to the same interface
 *         used by other architectures          /Roman Zippel
 */

#include <linux/module.h>
#include <linux/mm.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>

#include <asm/setup.h>
#include <asm/segment.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
#include <asm/io.h>
#include <asm/system.h>

#undef DEBUG

#define PTRTREESIZE     (256*1024)

/*
 * For 040/060 we can use the virtual memory area like other architectures,
 * but for 020/030 we want to use early termination page descriptor and we
 * can't mix this with normal page descriptors, so we have to copy that code
 * (mm/vmalloc.c) and return appriorate aligned addresses.
 */

#ifdef CPU_M68040_OR_M68060_ONLY

#define IO_SIZE         PAGE_SIZE

static inline struct vm_struct *get_io_area(unsigned long size)
{
      return get_vm_area(size, VM_IOREMAP);
}


static inline void free_io_area(void *addr)
{
      vfree((void *)(PAGE_MASK & (unsigned long)addr));
}

#else

#define IO_SIZE         (256*1024)

static struct vm_struct *iolist;

static struct vm_struct *get_io_area(unsigned long size)
{
      unsigned long addr;
      struct vm_struct **p, *tmp, *area;

      area = kmalloc(sizeof(*area), GFP_KERNEL);
      if (!area)
            return NULL;
      addr = KMAP_START;
      for (p = &iolist; (tmp = *p) ; p = &tmp->next) {
            if (size + addr < (unsigned long)tmp->addr)
                  break;
            if (addr > KMAP_END-size)
                  return NULL;
            addr = tmp->size + (unsigned long)tmp->addr;
      }
      area->addr = (void *)addr;
      area->size = size + IO_SIZE;
      area->next = *p;
      *p = area;
      return area;
}

static inline void free_io_area(void *addr)
{
      struct vm_struct **p, *tmp;

      if (!addr)
            return;
      addr = (void *)((unsigned long)addr & -IO_SIZE);
      for (p = &iolist ; (tmp = *p) ; p = &tmp->next) {
            if (tmp->addr == addr) {
                  *p = tmp->next;
                  __iounmap(tmp->addr, tmp->size);
                  kfree(tmp);
                  return;
            }
      }
}

#endif

/*
 * Map some physical address range into the kernel address space. The
 * code is copied and adapted from map_chunk().
 */
/* Rewritten by Andreas Schwab to remove all races. */

void __iomem *__ioremap(unsigned long physaddr, unsigned long size, int cacheflag)
{
      struct vm_struct *area;
      unsigned long virtaddr, retaddr;
      long offset;
      pgd_t *pgd_dir;
      pmd_t *pmd_dir;
      pte_t *pte_dir;

      /*
       * Don't allow mappings that wrap..
       */
      if (!size || size > physaddr + size)
            return NULL;

#ifdef CONFIG_AMIGA
      if (MACH_IS_AMIGA) {
            if ((physaddr >= 0x40000000) && (physaddr + size < 0x60000000)
                && (cacheflag == IOMAP_NOCACHE_SER))
                  return (void __iomem *)physaddr;
      }
#endif

#ifdef DEBUG
      printk("ioremap: 0x%lx,0x%lx(%d) - ", physaddr, size, cacheflag);
#endif
      /*
       * Mappings have to be aligned
       */
      offset = physaddr & (IO_SIZE - 1);
      physaddr &= -IO_SIZE;
      size = (size + offset + IO_SIZE - 1) & -IO_SIZE;

      /*
       * Ok, go for it..
       */
      area = get_io_area(size);
      if (!area)
            return NULL;

      virtaddr = (unsigned long)area->addr;
      retaddr = virtaddr + offset;
#ifdef DEBUG
      printk("0x%lx,0x%lx,0x%lx", physaddr, virtaddr, retaddr);
#endif

      /*
       * add cache and table flags to physical address
       */
      if (CPU_IS_040_OR_060) {
            physaddr |= (_PAGE_PRESENT | _PAGE_GLOBAL040 |
                       _PAGE_ACCESSED | _PAGE_DIRTY);
            switch (cacheflag) {
            case IOMAP_FULL_CACHING:
                  physaddr |= _PAGE_CACHE040;
                  break;
            case IOMAP_NOCACHE_SER:
            default:
                  physaddr |= _PAGE_NOCACHE_S;
                  break;
            case IOMAP_NOCACHE_NONSER:
                  physaddr |= _PAGE_NOCACHE;
                  break;
            case IOMAP_WRITETHROUGH:
                  physaddr |= _PAGE_CACHE040W;
                  break;
            }
      } else {
            physaddr |= (_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_DIRTY);
            switch (cacheflag) {
            case IOMAP_NOCACHE_SER:
            case IOMAP_NOCACHE_NONSER:
            default:
                  physaddr |= _PAGE_NOCACHE030;
                  break;
            case IOMAP_FULL_CACHING:
            case IOMAP_WRITETHROUGH:
                  break;
            }
      }

      while ((long)size > 0) {
#ifdef DEBUG
            if (!(virtaddr & (PTRTREESIZE-1)))
                  printk ("\npa=%#lx va=%#lx ", physaddr, virtaddr);
#endif
            pgd_dir = pgd_offset_k(virtaddr);
            pmd_dir = pmd_alloc(&init_mm, pgd_dir, virtaddr);
            if (!pmd_dir) {
                  printk("ioremap: no mem for pmd_dir\n");
                  return NULL;
            }

            if (CPU_IS_020_OR_030) {
                  pmd_dir->pmd[(virtaddr/PTRTREESIZE) & 15] = physaddr;
                  physaddr += PTRTREESIZE;
                  virtaddr += PTRTREESIZE;
                  size -= PTRTREESIZE;
            } else {
                  pte_dir = pte_alloc_kernel(pmd_dir, virtaddr);
                  if (!pte_dir) {
                        printk("ioremap: no mem for pte_dir\n");
                        return NULL;
                  }

                  pte_val(*pte_dir) = physaddr;
                  virtaddr += PAGE_SIZE;
                  physaddr += PAGE_SIZE;
                  size -= PAGE_SIZE;
            }
      }
#ifdef DEBUG
      printk("\n");
#endif
      flush_tlb_all();

      return (void __iomem *)retaddr;
}
EXPORT_SYMBOL(__ioremap);

/*
 * Unmap a ioremap()ed region again
 */
void iounmap(void __iomem *addr)
{
#ifdef CONFIG_AMIGA
      if ((!MACH_IS_AMIGA) ||
          (((unsigned long)addr < 0x40000000) ||
           ((unsigned long)addr > 0x60000000)))
                  free_io_area((__force void *)addr);
#else
      free_io_area((__force void *)addr);
#endif
}
EXPORT_SYMBOL(iounmap);

/*
 * __iounmap unmaps nearly everything, so be careful
 * it doesn't free currently pointer/page tables anymore but it
 * wans't used anyway and might be added later.
 */
void __iounmap(void *addr, unsigned long size)
{
      unsigned long virtaddr = (unsigned long)addr;
      pgd_t *pgd_dir;
      pmd_t *pmd_dir;
      pte_t *pte_dir;

      while ((long)size > 0) {
            pgd_dir = pgd_offset_k(virtaddr);
            if (pgd_bad(*pgd_dir)) {
                  printk("iounmap: bad pgd(%08lx)\n", pgd_val(*pgd_dir));
                  pgd_clear(pgd_dir);
                  return;
            }
            pmd_dir = pmd_offset(pgd_dir, virtaddr);

            if (CPU_IS_020_OR_030) {
                  int pmd_off = (virtaddr/PTRTREESIZE) & 15;
                  int pmd_type = pmd_dir->pmd[pmd_off] & _DESCTYPE_MASK;

                  if (pmd_type == _PAGE_PRESENT) {
                        pmd_dir->pmd[pmd_off] = 0;
                        virtaddr += PTRTREESIZE;
                        size -= PTRTREESIZE;
                        continue;
                  } else if (pmd_type == 0)
                        continue;
            }

            if (pmd_bad(*pmd_dir)) {
                  printk("iounmap: bad pmd (%08lx)\n", pmd_val(*pmd_dir));
                  pmd_clear(pmd_dir);
                  return;
            }
            pte_dir = pte_offset_kernel(pmd_dir, virtaddr);

            pte_val(*pte_dir) = 0;
            virtaddr += PAGE_SIZE;
            size -= PAGE_SIZE;
      }

      flush_tlb_all();
}

/*
 * Set new cache mode for some kernel address space.
 * The caller must push data for that range itself, if such data may already
 * be in the cache.
 */
void kernel_set_cachemode(void *addr, unsigned long size, int cmode)
{
      unsigned long virtaddr = (unsigned long)addr;
      pgd_t *pgd_dir;
      pmd_t *pmd_dir;
      pte_t *pte_dir;

      if (CPU_IS_040_OR_060) {
            switch (cmode) {
            case IOMAP_FULL_CACHING:
                  cmode = _PAGE_CACHE040;
                  break;
            case IOMAP_NOCACHE_SER:
            default:
                  cmode = _PAGE_NOCACHE_S;
                  break;
            case IOMAP_NOCACHE_NONSER:
                  cmode = _PAGE_NOCACHE;
                  break;
            case IOMAP_WRITETHROUGH:
                  cmode = _PAGE_CACHE040W;
                  break;
            }
      } else {
            switch (cmode) {
            case IOMAP_NOCACHE_SER:
            case IOMAP_NOCACHE_NONSER:
            default:
                  cmode = _PAGE_NOCACHE030;
                  break;
            case IOMAP_FULL_CACHING:
            case IOMAP_WRITETHROUGH:
                  cmode = 0;
            }
      }

      while ((long)size > 0) {
            pgd_dir = pgd_offset_k(virtaddr);
            if (pgd_bad(*pgd_dir)) {
                  printk("iocachemode: bad pgd(%08lx)\n", pgd_val(*pgd_dir));
                  pgd_clear(pgd_dir);
                  return;
            }
            pmd_dir = pmd_offset(pgd_dir, virtaddr);

            if (CPU_IS_020_OR_030) {
                  int pmd_off = (virtaddr/PTRTREESIZE) & 15;

                  if ((pmd_dir->pmd[pmd_off] & _DESCTYPE_MASK) == _PAGE_PRESENT) {
                        pmd_dir->pmd[pmd_off] = (pmd_dir->pmd[pmd_off] &
                                           _CACHEMASK040) | cmode;
                        virtaddr += PTRTREESIZE;
                        size -= PTRTREESIZE;
                        continue;
                  }
            }

            if (pmd_bad(*pmd_dir)) {
                  printk("iocachemode: bad pmd (%08lx)\n", pmd_val(*pmd_dir));
                  pmd_clear(pmd_dir);
                  return;
            }
            pte_dir = pte_offset_kernel(pmd_dir, virtaddr);

            pte_val(*pte_dir) = (pte_val(*pte_dir) & _CACHEMASK040) | cmode;
            virtaddr += PAGE_SIZE;
            size -= PAGE_SIZE;
      }

      flush_tlb_all();
}
EXPORT_SYMBOL(kernel_set_cachemode);

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