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 #if !defined(CONFIG_PMB_FIXED)
  63         /*
  64          * Don't allow anybody to remap normal RAM that we're using..
  65          */
  66         if (phys_addr < virt_to_phys(high_memory))
  67                 return NULL;
  68 #endif
  69
  70         /*
  71          * Mappings have to be page-aligned
  72          */
  73         offset = phys_addr & ~PAGE_MASK;
  74         phys_addr &= PAGE_MASK;
  75         size = PAGE_ALIGN(last_addr+1) - phys_addr;
  76
  77         /*
  78          * Ok, go for it..
  79          */
  80         area = get_vm_area(size, VM_IOREMAP);
  81         if (!area)
  82                 return NULL;
  83         area->phys_addr = phys_addr;
  84         orig_addr = addr = (unsigned long)area->addr;
  85
  86 #ifdef CONFIG_PMB
  87         /*
  88          * First try to remap through the PMB once a valid VMA has been
  89          * established. Smaller allocations (or the rest of the size
  90          * remaining after a PMB mapping due to the size not being
  91          * perfectly aligned on a PMB size boundary) are then mapped
  92          * through the UTLB using conventional page tables.
  93          *
  94          * PMB entries are all pre-faulted.
  95          */
  96         if (unlikely(size >= 0x1000000)) {
  97                 unsigned long mapped = pmb_remap(addr, phys_addr, size, flags);
  98
  99                 if (likely(mapped)) {
 100                         addr            += mapped;
 101                         phys_addr       += mapped;
 102                         size            -= mapped;
 103                 }
 104         }
 105 #endif
 106
 107         pgprot = __pgprot(pgprot_val(PAGE_KERNEL_NOCACHE) | flags);
 108         if (likely(size))
 109                 if (ioremap_page_range(addr, addr + size, phys_addr, pgprot)) {
 110                         vunmap((void *)orig_addr);
 111                         return NULL;
 112                 }
 113
 114         return (void __iomem *)(offset + (char *)orig_addr);
 115 }
 116 EXPORT_SYMBOL(__ioremap);
 117
 118 void __iounmap(void __iomem *addr)
 119 {
 120         unsigned long vaddr = (unsigned long __force)addr;
 121         unsigned long seg = PXSEG(vaddr);
 122         struct vm_struct *p;
 123
 124         if (seg < P3SEG || vaddr >= P3_ADDR_MAX || is_pci_memaddr(vaddr))
 125                 return;
 126
 127 #ifdef CONFIG_PMB
 128         /*
 129          * Purge any PMB entries that may have been established for this
 130          * mapping, then proceed with conventional VMA teardown.
 131          *
 132          * XXX: Note that due to the way that remove_vm_area() does
 133          * matching of the resultant VMA, we aren't able to fast-forward
 134          * the address past the PMB space until the end of the VMA where
 135          * the page tables reside. As such, unmap_vm_area() will be
 136          * forced to linearly scan over the area until it finds the page
 137          * tables where PTEs that need to be unmapped actually reside,
 138          * which is far from optimal. Perhaps we need to use a separate
 139          * VMA for the PMB mappings?
 140          *                                      -- PFM.
 141          */
 142         pmb_unmap(vaddr);
 143 #endif
 144
 145         p = remove_vm_area((void *)(vaddr & PAGE_MASK));
 146         if (!p) {
 147                 printk(KERN_ERR "%s: bad address %p\n", __func__, addr);
 148                 return;
 149         }
 150
 151         kfree(p);
 152 }
 153 EXPORT_SYMBOL(__iounmap);