arch/sh/mm/ioremap_32.c

   1 /*
   2  * arch/sh/mm/ioremap.c
   3  *
   4  * Re-map IO memory to kernel address space so that we can access it.
   5  * This is needed for high PCI addresses that aren't mapped in the
   6  * 640k-1MB IO memory area on PC's
   7  *
   8  * (C) Copyright 1995 1996 Linus Torvalds
   9  * (C) Copyright 2005, 2006 Paul Mundt
  10  *
  11  * This file is subject to the terms and conditions of the GNU General
  12  * Public License. See the file "COPYING" in the main directory of this
  13  * archive for more details.
  14  */
  15 #include <linux/vmalloc.h>
  16 #include <linux/module.h>
  17 #include <linux/mm.h>
  18 #include <linux/pci.h>
  19 #include <linux/io.h>
  20 #include <asm/page.h>
  21 #include <asm/pgalloc.h>
  22 #include <asm/addrspace.h>
  23 #include <asm/cacheflush.h>
  24 #include <asm/tlbflush.h>
  25 #include <asm/mmu.h>
  26
  27 /*
  28  * Remap an arbitrary physical address space into the kernel virtual
  29  * address space. Needed when the kernel wants to access high addresses
  30  * directly.
  31  *
  32  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
  33  * have to convert them into an offset in a page-aligned mapping, but the
  34  * caller shouldn't need to know that small detail.
  35  */
  36 void __iomem *__ioremap(unsigned long phys_addr, unsigned long size,
  37                         unsigned long flags)
  38 {
  39         struct vm_struct * area;
  40         unsigned long offset, last_addr, addr, orig_addr;
  41         pgprot_t pgprot;
  42
  43         /* Don't allow wraparound or zero size */
  44         last_addr = phys_addr + size - 1;
  45         if (!size || last_addr < phys_addr)
  46                 return NULL;
  47
  48         /*
  49          * If we're on an SH7751 or SH7780 PCI controller, PCI memory is
  50          * mapped at the end of the address space (typically 0xfd000000)
  51          * in a non-translatable area, so mapping through page tables for
  52          * this area is not only pointless, but also fundamentally
  53          * broken. Just return the physical address instead.
  54          *
  55          * For boards that map a small PCI memory aperture somewhere in
  56          * P1/P2 space, ioremap() will already do the right thing,
  57          * and we'll never get this far.
  58          */
  59         if (is_pci_memaddr(phys_addr) && is_pci_memaddr(last_addr))
  60                 return (void __iomem *)phys_addr;
  61
  62         /*
  63          * Don't allow anybody to remap normal RAM that we're using..
  64          */
  65         if (phys_addr < virt_to_phys(high_memory))
  66                 return NULL;
  67
  68         /*
  69          * Mappings have to be page-aligned
  70          */
  71         offset = phys_addr & ~PAGE_MASK;
  72         phys_addr &= PAGE_MASK;
  73         size = PAGE_ALIGN(last_addr+1) - phys_addr;
  74
  75         /*
  76          * Ok, go for it..
  77          */
  78         area = get_vm_area(size, VM_IOREMAP);
  79         if (!area)
  80                 return NULL;
  81         area->phys_addr = phys_addr;
  82         orig_addr = addr = (unsigned long)area->addr;
  83
  84 #ifdef CONFIG_32BIT
  85         /*
  86          * First try to remap through the PMB once a valid VMA has been
  87          * established. Smaller allocations (or the rest of the size
  88          * remaining after a PMB mapping due to the size not being
  89          * perfectly aligned on a PMB size boundary) are then mapped
  90          * through the UTLB using conventional page tables.
  91          *
  92          * PMB entries are all pre-faulted.
  93          */
  94         if (unlikely(size >= 0x1000000)) {
  95                 unsigned long mapped = pmb_remap(addr, phys_addr, size, flags);
  96
  97                 if (likely(mapped)) {
  98                         addr            += mapped;
  99                         phys_addr       += mapped;
 100                         size            -= mapped;
 101                 }
 102         }
 103 #endif
 104
 105         pgprot = __pgprot(pgprot_val(PAGE_KERNEL_NOCACHE) | flags);
 106         if (likely(size))
 107                 if (ioremap_page_range(addr, addr + size, phys_addr, pgprot)) {
 108                         vunmap((void *)orig_addr);
 109                         return NULL;
 110                 }
 111
 112         return (void __iomem *)(offset + (char *)orig_addr);
 113 }
 114 EXPORT_SYMBOL(__ioremap);
 115
 116 void __iounmap(void __iomem *addr)
 117 {
 118         unsigned long vaddr = (unsigned long __force)addr;
 119         struct vm_struct *p;
 120
 121         if (PXSEG(vaddr) < P3SEG || is_pci_memaddr(vaddr))
 122                 return;
 123
 124 #ifdef CONFIG_32BIT
 125         /*
 126          * Purge any PMB entries that may have been established for this
 127          * mapping, then proceed with conventional VMA teardown.
 128          *
 129          * XXX: Note that due to the way that remove_vm_area() does
 130          * matching of the resultant VMA, we aren't able to fast-forward
 131          * the address past the PMB space until the end of the VMA where
 132          * the page tables reside. As such, unmap_vm_area() will be
 133          * forced to linearly scan over the area until it finds the page
 134          * tables where PTEs that need to be unmapped actually reside,
 135          * which is far from optimal. Perhaps we need to use a separate
 136          * VMA for the PMB mappings?
 137          *                                      -- PFM.
 138          */
 139         pmb_unmap(vaddr);
 140 #endif
 141
 142         p = remove_vm_area((void *)(vaddr & PAGE_MASK));
 143         if (!p) {
 144                 printk(KERN_ERR "%s: bad address %p\n", __func__, addr);
 145                 return;
 146         }
 147
 148         kfree(p);
 149 }
 150 EXPORT_SYMBOL(__iounmap);