1 /* 2 * linux/arch/arm/mm/ioremap.c 3 * 4 * Re-map IO memory to kernel address space so that we can access it. 5 * 6 * (C) Copyright 1995 1996 Linus Torvalds 7 * 8 * Hacked for ARM by Phil Blundell <philb@gnu.org> 9 * Hacked to allow all architectures to build, and various cleanups 10 * by Russell King 11 * 12 * This allows a driver to remap an arbitrary region of bus memory into 13 * virtual space. One should *only* use readl, writel, memcpy_toio and 14 * so on with such remapped areas. 15 * 16 * Because the ARM only has a 32-bit address space we can't address the 17 * whole of the (physical) PCI space at once. PCI huge-mode addressing 18 * allows us to circumvent this restriction by splitting PCI space into 19 * two 2GB chunks and mapping only one at a time into processor memory. 20 * We use MMU protection domains to trap any attempt to access the bank 21 * that is not currently mapped. (This isn't fully implemented yet.) 22 */ 23 #include <linux/module.h> 24 #include <linux/errno.h> 25 #include <linux/mm.h> 26 #include <linux/vmalloc.h> 27 28 #include <asm/cacheflush.h> 29 #include <asm/io.h> 30 #include <asm/tlbflush.h> 31 32 static inline void 33 remap_area_pte(pte_t * pte, unsigned long address, unsigned long size, 34 unsigned long phys_addr, pgprot_t pgprot) 35 { 36 unsigned long end; 37 38 address &= ~PMD_MASK; 39 end = address + size; 40 if (end > PMD_SIZE) 41 end = PMD_SIZE; 42 BUG_ON(address >= end); 43 do { 44 if (!pte_none(*pte)) 45 goto bad; 46 47 set_pte(pte, pfn_pte(phys_addr >> PAGE_SHIFT, pgprot)); 48 address += PAGE_SIZE; 49 phys_addr += PAGE_SIZE; 50 pte++; 51 } while (address && (address < end)); 52 return; 53 54 bad: 55 printk("remap_area_pte: page already exists\n"); 56 BUG(); 57 } 58 59 static inline int 60 remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size, 61 unsigned long phys_addr, unsigned long flags) 62 { 63 unsigned long end; 64 pgprot_t pgprot; 65 66 address &= ~PGDIR_MASK; 67 end = address + size; 68 69 if (end > PGDIR_SIZE) 70 end = PGDIR_SIZE; 71 72 phys_addr -= address; 73 BUG_ON(address >= end); 74 75 pgprot = __pgprot(L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY | L_PTE_WRITE | flags); 76 do { 77 pte_t * pte = pte_alloc_kernel(pmd, address); 78 if (!pte) 79 return -ENOMEM; 80 remap_area_pte(pte, address, end - address, address + phys_addr, pgprot); 81 address = (address + PMD_SIZE) & PMD_MASK; 82 pmd++; 83 } while (address && (address < end)); 84 return 0; 85 } 86 87 static int 88 remap_area_pages(unsigned long start, unsigned long pfn, 89 unsigned long size, unsigned long flags) 90 { 91 unsigned long address = start; 92 unsigned long end = start + size; 93 unsigned long phys_addr = __pfn_to_phys(pfn); 94 int err = 0; 95 pgd_t * dir; 96 97 phys_addr -= address; 98 dir = pgd_offset(&init_mm, address); 99 BUG_ON(address >= end); 100 do { 101 pmd_t *pmd = pmd_alloc(&init_mm, dir, address); 102 if (!pmd) { 103 err = -ENOMEM; 104 break; 105 } 106 if (remap_area_pmd(pmd, address, end - address, 107 phys_addr + address, flags)) { 108 err = -ENOMEM; 109 break; 110 } 111 112 address = (address + PGDIR_SIZE) & PGDIR_MASK; 113 dir++; 114 } while (address && (address < end)); 115 116 flush_cache_vmap(start, end); 117 return err; 118 } 119 120 /* 121 * Remap an arbitrary physical address space into the kernel virtual 122 * address space. Needed when the kernel wants to access high addresses 123 * directly. 124 * 125 * NOTE! We need to allow non-page-aligned mappings too: we will obviously 126 * have to convert them into an offset in a page-aligned mapping, but the 127 * caller shouldn't need to know that small detail. 128 * 129 * 'flags' are the extra L_PTE_ flags that you want to specify for this 130 * mapping. See include/asm-arm/proc-armv/pgtable.h for more information. 131 */ 132 void __iomem * 133 __ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size, 134 unsigned long flags) 135 { 136 unsigned long addr; 137 struct vm_struct * area; 138 139 area = get_vm_area(size, VM_IOREMAP); 140 if (!area) 141 return NULL; 142 addr = (unsigned long)area->addr; 143 if (remap_area_pages(addr, pfn, size, flags)) { 144 vunmap((void *)addr); 145 return NULL; 146 } 147 return (void __iomem *) (offset + (char *)addr); 148 } 149 EXPORT_SYMBOL(__ioremap_pfn); 150 151 void __iomem * 152 __ioremap(unsigned long phys_addr, size_t size, unsigned long flags) 153 { 154 unsigned long last_addr; 155 unsigned long offset = phys_addr & ~PAGE_MASK; 156 unsigned long pfn = __phys_to_pfn(phys_addr); 157 158 /* 159 * Don't allow wraparound or zero size 160 */ 161 last_addr = phys_addr + size - 1; 162 if (!size || last_addr < phys_addr) 163 return NULL; 164 165 /* 166 * Page align the mapping size 167 */ 168 size = PAGE_ALIGN(last_addr + 1) - phys_addr; 169 170 return __ioremap_pfn(pfn, offset, size, flags); 171 } 172 EXPORT_SYMBOL(__ioremap); 173 174 void __iounmap(void __iomem *addr) 175 { 176 vunmap((void *)(PAGE_MASK & (unsigned long)addr)); 177 } 178 EXPORT_SYMBOL(__iounmap); 179 180 #ifdef __io 181 void __iomem *ioport_map(unsigned long port, unsigned int nr) 182 { 183 return __io(port); 184 } 185 EXPORT_SYMBOL(ioport_map); 186 187 void ioport_unmap(void __iomem *addr) 188 { 189 } 190 EXPORT_SYMBOL(ioport_unmap); 191 #endif 192 193 #ifdef CONFIG_PCI 194 #include <linux/pci.h> 195 #include <linux/ioport.h> 196 197 void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen) 198 { 199 unsigned long start = pci_resource_start(dev, bar); 200 unsigned long len = pci_resource_len(dev, bar); 201 unsigned long flags = pci_resource_flags(dev, bar); 202 203 if (!len || !start) 204 return NULL; 205 if (maxlen && len > maxlen) 206 len = maxlen; 207 if (flags & IORESOURCE_IO) 208 return ioport_map(start, len); 209 if (flags & IORESOURCE_MEM) { 210 if (flags & IORESOURCE_CACHEABLE) 211 return ioremap(start, len); 212 return ioremap_nocache(start, len); 213 } 214 return NULL; 215 } 216 EXPORT_SYMBOL(pci_iomap); 217 218 void pci_iounmap(struct pci_dev *dev, void __iomem *addr) 219 { 220 if ((unsigned long)addr >= VMALLOC_START && 221 (unsigned long)addr < VMALLOC_END) 222 iounmap(addr); 223 } 224 EXPORT_SYMBOL(pci_iounmap); 225 #endif 226