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(phys_addr_t 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         void __iomem *mapped;
  43
  44         /* Don't allow wraparound or zero size */
  45         last_addr = phys_addr + size - 1;
  46         if (!size || last_addr < phys_addr)
  47                 return NULL;
  48
  49         /*
  50          * If we can't yet use the regular approach, go the fixmap route.
  51          */
  52         if (!mem_init_done)
  53                 return ioremap_fixed(phys_addr, size, pgprot);
  54
  55         /*
  56          * First try to remap through the PMB.
  57          * PMB entries are all pre-faulted.
  58          */
  59         mapped = pmb_remap_caller(phys_addr, size, pgprot, caller);
  60         if (mapped && !IS_ERR(mapped))
  61                 return mapped;
  62
  63         /*
  64          * Mappings have to be page-aligned
  65          */
  66         offset = phys_addr & ~PAGE_MASK;
  67         phys_addr &= PAGE_MASK;
  68         size = PAGE_ALIGN(last_addr+1) - phys_addr;
  69
  70         /*
  71          * Ok, go for it..
  72          */
  73         area = get_vm_area_caller(size, VM_IOREMAP, caller);
  74         if (!area)
  75                 return NULL;
  76         area->phys_addr = phys_addr;
  77         orig_addr = addr = (unsigned long)area->addr;
  78
  79         if (ioremap_page_range(addr, addr + size, phys_addr, pgprot)) {
  80                 vunmap((void *)orig_addr);
  81                 return NULL;
  82         }
  83
  84         return (void __iomem *)(offset + (char *)orig_addr);
  85 }
  86 EXPORT_SYMBOL(__ioremap_caller);
  87
  88 /*
  89  * Simple checks for non-translatable mappings.
  90  */
  91 static inline int iomapping_nontranslatable(unsigned long offset)
  92 {
  93 #ifdef CONFIG_29BIT
  94         /*
  95          * In 29-bit mode this includes the fixed P1/P2 areas, as well as
  96          * parts of P3.
  97          */
  98         if (PXSEG(offset) < P3SEG || offset >= P3_ADDR_MAX)
  99                 return 1;
 100 #endif
 101
 102         return 0;
 103 }
 104
 105 void __iounmap(void __iomem *addr)
 106 {
 107         unsigned long vaddr = (unsigned long __force)addr;
 108         struct vm_struct *p;
 109
 110         /*
 111          * Nothing to do if there is no translatable mapping.
 112          */
 113         if (iomapping_nontranslatable(vaddr))
 114                 return;
 115
 116         /*
 117          * There's no VMA if it's from an early fixed mapping.
 118          */
 119         if (iounmap_fixed(addr) == 0)
 120                 return;
 121
 122         /*
 123          * If the PMB handled it, there's nothing else to do.
 124          */
 125         if (pmb_unmap(addr) == 0)
 126                 return;
 127
 128         p = remove_vm_area((void *)(vaddr & PAGE_MASK));
 129         if (!p) {
 130                 printk(KERN_ERR "%s: bad address %p\n", __func__, addr);
 131                 return;
 132         }
 133
 134         kfree(p);
 135 }
 136 EXPORT_SYMBOL(__iounmap);