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/slab.h>
  18 #include <linux/mm.h>
  19 #include <linux/pci.h>
  20 #include <linux/io.h>
  21 #include <asm/io_trapped.h>
  22 #include <asm/page.h>
  23 #include <asm/pgalloc.h>
  24 #include <asm/addrspace.h>
  25 #include <asm/cacheflush.h>
  26 #include <asm/tlbflush.h>
  27 #include <asm/mmu.h>
  28 #include "ioremap.h"
  29
  30 /*
  31  * On 32-bit SH, we traditionally have the whole physical address space mapped
  32  * at all times (as MIPS does), so "ioremap()" and "iounmap()" do not need to do
  33  * anything but place the address in the proper segment.  This is true for P1
  34  * and P2 addresses, as well as some P3 ones.  However, most of the P3 addresses
  35  * and newer cores using extended addressing need to map through page tables, so
  36  * the ioremap() implementation becomes a bit more complicated.
  37  */
  38 #ifdef CONFIG_29BIT
  39 static void __iomem *
  40 __ioremap_29bit(phys_addr_t offset, unsigned long size, pgprot_t prot)
  41 {
  42         phys_addr_t last_addr = offset + size - 1;
  43
  44         /*
  45          * For P1 and P2 space this is trivial, as everything is already
  46          * mapped. Uncached access for P1 addresses are done through P2.
  47          * In the P3 case or for addresses outside of the 29-bit space,
  48          * mapping must be done by the PMB or by using page tables.
  49          */
  50         if (likely(PXSEG(offset) < P3SEG && PXSEG(last_addr) < P3SEG)) {
  51                 u64 flags = pgprot_val(prot);
  52
  53                 /*
  54                  * Anything using the legacy PTEA space attributes needs
  55                  * to be kicked down to page table mappings.
  56                  */
  57                 if (unlikely(flags & _PAGE_PCC_MASK))
  58                         return NULL;
  59                 if (unlikely(flags & _PAGE_CACHABLE))
  60                         return (void __iomem *)P1SEGADDR(offset);
  61
  62                 return (void __iomem *)P2SEGADDR(offset);
  63         }
  64
  65         /* P4 above the store queues are always mapped. */
  66         if (unlikely(offset >= P3_ADDR_MAX))
  67                 return (void __iomem *)P4SEGADDR(offset);
  68
  69         return NULL;
  70 }
  71 #else
  72 #define __ioremap_29bit(offset, size, prot)             NULL
  73 #endif /* CONFIG_29BIT */
  74
  75 /*
  76  * Remap an arbitrary physical address space into the kernel virtual
  77  * address space. Needed when the kernel wants to access high addresses
  78  * directly.
  79  *
  80  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
  81  * have to convert them into an offset in a page-aligned mapping, but the
  82  * caller shouldn't need to know that small detail.
  83  */
  84 void __iomem * __ref
  85 __ioremap_caller(phys_addr_t phys_addr, unsigned long size,
  86                  pgprot_t pgprot, void *caller)
  87 {
  88         struct vm_struct *area;
  89         unsigned long offset, last_addr, addr, orig_addr;
  90         void __iomem *mapped;
  91
  92         mapped = __ioremap_trapped(phys_addr, size);
  93         if (mapped)
  94                 return mapped;
  95
  96         mapped = __ioremap_29bit(phys_addr, size, pgprot);
  97         if (mapped)
  98                 return mapped;
  99
 100         /* Don't allow wraparound or zero size */
 101         last_addr = phys_addr + size - 1;
 102         if (!size || last_addr < phys_addr)
 103                 return NULL;
 104
 105         /*
 106          * If we can't yet use the regular approach, go the fixmap route.
 107          */
 108         if (!mem_init_done)
 109                 return ioremap_fixed(phys_addr, size, pgprot);
 110
 111         /*
 112          * First try to remap through the PMB.
 113          * PMB entries are all pre-faulted.
 114          */
 115         mapped = pmb_remap_caller(phys_addr, size, pgprot, caller);
 116         if (mapped && !IS_ERR(mapped))
 117                 return mapped;
 118
 119         /*
 120          * Mappings have to be page-aligned
 121          */
 122         offset = phys_addr & ~PAGE_MASK;
 123         phys_addr &= PAGE_MASK;
 124         size = PAGE_ALIGN(last_addr+1) - phys_addr;
 125
 126         /*
 127          * Ok, go for it..
 128          */
 129         area = get_vm_area_caller(size, VM_IOREMAP, caller);
 130         if (!area)
 131                 return NULL;
 132         area->phys_addr = phys_addr;
 133         orig_addr = addr = (unsigned long)area->addr;
 134
 135         if (ioremap_page_range(addr, addr + size, phys_addr, pgprot)) {
 136                 vunmap((void *)orig_addr);
 137                 return NULL;
 138         }
 139
 140         return (void __iomem *)(offset + (char *)orig_addr);
 141 }
 142 EXPORT_SYMBOL(__ioremap_caller);
 143
 144 /*
 145  * Simple checks for non-translatable mappings.
 146  */
 147 static inline int iomapping_nontranslatable(unsigned long offset)
 148 {
 149 #ifdef CONFIG_29BIT
 150         /*
 151          * In 29-bit mode this includes the fixed P1/P2 areas, as well as
 152          * parts of P3.
 153          */
 154         if (PXSEG(offset) < P3SEG || offset >= P3_ADDR_MAX)
 155                 return 1;
 156 #endif
 157
 158         return 0;
 159 }
 160
 161 void iounmap(void __iomem *addr)
 162 {
 163         unsigned long vaddr = (unsigned long __force)addr;
 164         struct vm_struct *p;
 165
 166         /*
 167          * Nothing to do if there is no translatable mapping.
 168          */
 169         if (iomapping_nontranslatable(vaddr))
 170                 return;
 171
 172         /*
 173          * There's no VMA if it's from an early fixed mapping.
 174          */
 175         if (iounmap_fixed(addr) == 0)
 176                 return;
 177
 178         /*
 179          * If the PMB handled it, there's nothing else to do.
 180          */
 181         if (pmb_unmap(addr) == 0)
 182                 return;
 183
 184         p = remove_vm_area((void *)(vaddr & PAGE_MASK));
 185         if (!p) {
 186                 printk(KERN_ERR "%s: bad address %p\n", __func__, addr);
 187                 return;
 188         }
 189
 190         kfree(p);
 191 }
 192 EXPORT_SYMBOL(iounmap);