arch/sh/mm/ioremap.c

   1 /*
   2  * arch/sh/mm/ioremap.c
   3  *
   4  * (C) Copyright 1995 1996 Linus Torvalds
   5  * (C) Copyright 2005 - 2010  Paul Mundt
   6  *
   7  * Re-map IO memory to kernel address space so that we can access it.
   8  * This is needed for high PCI addresses that aren't mapped in the
   9  * 640k-1MB IO memory area on PC's
  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 * __init_refok
  37 __ioremap_caller(unsigned long phys_addr, unsigned long size,
  38                  pgprot_t pgprot, void *caller)
  39 {
  40         struct vm_struct *area;
  41         unsigned long offset, last_addr, addr, orig_addr;
  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          * Mappings have to be page-aligned
  50          */
  51         offset = phys_addr & ~PAGE_MASK;
  52         phys_addr &= PAGE_MASK;
  53         size = PAGE_ALIGN(last_addr+1) - phys_addr;
  54
  55         /*
  56          * If we can't yet use the regular approach, go the fixmap route.
  57          */
  58         if (!mem_init_done)
  59                 return ioremap_fixed(phys_addr, offset, size, pgprot);
  60
  61         /*
  62          * Ok, go for it..
  63          */
  64         area = get_vm_area_caller(size, VM_IOREMAP, caller);
  65         if (!area)
  66                 return NULL;
  67         area->phys_addr = phys_addr;
  68         orig_addr = addr = (unsigned long)area->addr;
  69
  70 #ifdef CONFIG_PMB
  71         /*
  72          * First try to remap through the PMB once a valid VMA has been
  73          * established. Smaller allocations (or the rest of the size
  74          * remaining after a PMB mapping due to the size not being
  75          * perfectly aligned on a PMB size boundary) are then mapped
  76          * through the UTLB using conventional page tables.
  77          *
  78          * PMB entries are all pre-faulted.
  79          */
  80         if (unlikely(phys_addr >= P1SEG)) {
  81                 unsigned long mapped;
  82
  83                 mapped = pmb_remap(addr, phys_addr, size, pgprot);
  84                 if (likely(mapped)) {
  85                         addr            += mapped;
  86                         phys_addr       += mapped;
  87                         size            -= mapped;
  88                 }
  89         }
  90 #endif
  91
  92         if (likely(size))
  93                 if (ioremap_page_range(addr, addr + size, phys_addr, pgprot)) {
  94                         vunmap((void *)orig_addr);
  95                         return NULL;
  96                 }
  97
  98         return (void __iomem *)(offset + (char *)orig_addr);
  99 }
 100 EXPORT_SYMBOL(__ioremap_caller);
 101
 102 /*
 103  * Simple checks for non-translatable mappings.
 104  */
 105 static inline int iomapping_nontranslatable(unsigned long offset)
 106 {
 107 #ifdef CONFIG_29BIT
 108         /*
 109          * In 29-bit mode this includes the fixed P1/P2 areas, as well as
 110          * parts of P3.
 111          */
 112         if (PXSEG(offset) < P3SEG || offset >= P3_ADDR_MAX)
 113                 return 1;
 114 #endif
 115
 116         return 0;
 117 }
 118
 119 void __iounmap(void __iomem *addr)
 120 {
 121         unsigned long vaddr = (unsigned long __force)addr;
 122         struct vm_struct *p;
 123
 124         /*
 125          * Nothing to do if there is no translatable mapping.
 126          */
 127         if (iomapping_nontranslatable(vaddr))
 128                 return;
 129
 130         /*
 131          * There's no VMA if it's from an early fixed mapping.
 132          */
 133         if (iounmap_fixed(addr) == 0)
 134                 return;
 135
 136 #ifdef CONFIG_PMB
 137         /*
 138          * Purge any PMB entries that may have been established for this
 139          * mapping, then proceed with conventional VMA teardown.
 140          *
 141          * XXX: Note that due to the way that remove_vm_area() does
 142          * matching of the resultant VMA, we aren't able to fast-forward
 143          * the address past the PMB space until the end of the VMA where
 144          * the page tables reside. As such, unmap_vm_area() will be
 145          * forced to linearly scan over the area until it finds the page
 146          * tables where PTEs that need to be unmapped actually reside,
 147          * which is far from optimal. Perhaps we need to use a separate
 148          * VMA for the PMB mappings?
 149          *                                      -- PFM.
 150          */
 151         pmb_unmap(vaddr);
 152 #endif
 153
 154         p = remove_vm_area((void *)(vaddr & PAGE_MASK));
 155         if (!p) {
 156                 printk(KERN_ERR "%s: bad address %p\n", __func__, addr);
 157                 return;
 158         }
 159
 160         kfree(p);
 161 }
 162 EXPORT_SYMBOL(__iounmap);