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_caller(unsigned long phys_addr, unsigned long size,
  37                                unsigned long flags, void *caller)
  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 in the fixed PCI memory range, mapping through page
  50          * tables is not only pointless, but also fundamentally broken.
  51          * Just return the physical address instead.
  52          *
  53          * For boards that map a small PCI memory aperture somewhere in
  54          * P1/P2 space, ioremap() will already do the right thing,
  55          * and we'll never get this far.
  56          */
  57         if (is_pci_memory_fixed_range(phys_addr, size))
  58                 return (void __iomem *)phys_addr;
  59
  60         /*
  61          * Mappings have to be page-aligned
  62          */
  63         offset = phys_addr & ~PAGE_MASK;
  64         phys_addr &= PAGE_MASK;
  65         size = PAGE_ALIGN(last_addr+1) - phys_addr;
  66
  67         /*
  68          * Ok, go for it..
  69          */
  70         area = get_vm_area_caller(size, VM_IOREMAP, caller);
  71         if (!area)
  72                 return NULL;
  73         area->phys_addr = phys_addr;
  74         orig_addr = addr = (unsigned long)area->addr;
  75
  76 #ifdef CONFIG_PMB
  77         /*
  78          * First try to remap through the PMB once a valid VMA has been
  79          * established. Smaller allocations (or the rest of the size
  80          * remaining after a PMB mapping due to the size not being
  81          * perfectly aligned on a PMB size boundary) are then mapped
  82          * through the UTLB using conventional page tables.
  83          *
  84          * PMB entries are all pre-faulted.
  85          */
  86         if (unlikely(phys_addr >= P1SEG)) {
  87                 unsigned long mapped = pmb_remap(addr, phys_addr, size, flags);
  88
  89                 if (likely(mapped)) {
  90                         addr            += mapped;
  91                         phys_addr       += mapped;
  92                         size            -= mapped;
  93                 }
  94         }
  95 #endif
  96
  97         pgprot = __pgprot(pgprot_val(PAGE_KERNEL_NOCACHE) | flags);
  98         if (likely(size))
  99                 if (ioremap_page_range(addr, addr + size, phys_addr, pgprot)) {
 100                         vunmap((void *)orig_addr);
 101                         return NULL;
 102                 }
 103
 104         return (void __iomem *)(offset + (char *)orig_addr);
 105 }
 106 EXPORT_SYMBOL(__ioremap_caller);
 107
 108 void __iounmap(void __iomem *addr)
 109 {
 110         unsigned long vaddr = (unsigned long __force)addr;
 111         unsigned long seg = PXSEG(vaddr);
 112         struct vm_struct *p;
 113
 114         if (seg < P3SEG || vaddr >= P3_ADDR_MAX)
 115                 return;
 116         if (is_pci_memory_fixed_range(vaddr, 0))
 117                 return;
 118
 119 #ifdef CONFIG_PMB
 120         /*
 121          * Purge any PMB entries that may have been established for this
 122          * mapping, then proceed with conventional VMA teardown.
 123          *
 124          * XXX: Note that due to the way that remove_vm_area() does
 125          * matching of the resultant VMA, we aren't able to fast-forward
 126          * the address past the PMB space until the end of the VMA where
 127          * the page tables reside. As such, unmap_vm_area() will be
 128          * forced to linearly scan over the area until it finds the page
 129          * tables where PTEs that need to be unmapped actually reside,
 130          * which is far from optimal. Perhaps we need to use a separate
 131          * VMA for the PMB mappings?
 132          *                                      -- PFM.
 133          */
 134         pmb_unmap(vaddr);
 135 #endif
 136
 137         p = remove_vm_area((void *)(vaddr & PAGE_MASK));
 138         if (!p) {
 139                 printk(KERN_ERR "%s: bad address %p\n", __func__, addr);
 140                 return;
 141         }
 142
 143         kfree(p);
 144 }
 145 EXPORT_SYMBOL(__iounmap);