ioremap.c (5034B)
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 39static 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 */ 84void __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} 142EXPORT_SYMBOL(__ioremap_caller); 143 144/* 145 * Simple checks for non-translatable mappings. 146 */ 147static 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 161void 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} 192EXPORT_SYMBOL(iounmap);