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/hardware.h> 30 #include <asm/io.h> 31 #include <asm/tlbflush.h> 32 33 static inline void 34 remap_area_pte(pte_t * pte, unsigned long address, unsigned long size, 35 unsigned long phys_addr, pgprot_t pgprot) 36 { 37 unsigned long end; 38 39 address &= ~PMD_MASK; 40 end = address + size; 41 if (end > PMD_SIZE) 42 end = PMD_SIZE; 43 BUG_ON(address >= end); 44 do { 45 if (!pte_none(*pte)) 46 goto bad; 47 48 set_pte(pte, pfn_pte(phys_addr >> PAGE_SHIFT, pgprot)); 49 address += PAGE_SIZE; 50 phys_addr += PAGE_SIZE; 51 pte++; 52 } while (address && (address < end)); 53 return; 54 55 bad: 56 printk("remap_area_pte: page already exists\n"); 57 BUG(); 58 } 59 60 static inline int 61 remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size, 62 unsigned long phys_addr, unsigned long flags) 63 { 64 unsigned long end; 65 pgprot_t pgprot; 66 67 address &= ~PGDIR_MASK; 68 end = address + size; 69 70 if (end > PGDIR_SIZE) 71 end = PGDIR_SIZE; 72 73 phys_addr -= address; 74 BUG_ON(address >= end); 75 76 pgprot = __pgprot(L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY | L_PTE_WRITE | flags); 77 do { 78 pte_t * pte = pte_alloc_kernel(pmd, address); 79 if (!pte) 80 return -ENOMEM; 81 remap_area_pte(pte, address, end - address, address + phys_addr, pgprot); 82 address = (address + PMD_SIZE) & PMD_MASK; 83 pmd++; 84 } while (address && (address < end)); 85 return 0; 86 } 87 88 static int 89 remap_area_pages(unsigned long start, unsigned long pfn, 90 unsigned long size, unsigned long flags) 91 { 92 unsigned long address = start; 93 unsigned long end = start + size; 94 unsigned long phys_addr = __pfn_to_phys(pfn); 95 int err = 0; 96 pgd_t * dir; 97 98 phys_addr -= address; 99 dir = pgd_offset(&init_mm, address); 100 BUG_ON(address >= end); 101 do { 102 pmd_t *pmd = pmd_alloc(&init_mm, dir, address); 103 if (!pmd) { 104 err = -ENOMEM; 105 break; 106 } 107 if (remap_area_pmd(pmd, address, end - address, 108 phys_addr + address, flags)) { 109 err = -ENOMEM; 110 break; 111 } 112 113 address = (address + PGDIR_SIZE) & PGDIR_MASK; 114 dir++; 115 } while (address && (address < end)); 116 117 flush_cache_vmap(start, end); 118 return err; 119 } 120 121 /* 122 * Remap an arbitrary physical address space into the kernel virtual 123 * address space. Needed when the kernel wants to access high addresses 124 * directly. 125 * 126 * NOTE! We need to allow non-page-aligned mappings too: we will obviously 127 * have to convert them into an offset in a page-aligned mapping, but the 128 * caller shouldn't need to know that small detail. 129 * 130 * 'flags' are the extra L_PTE_ flags that you want to specify for this 131 * mapping. See include/asm-arm/proc-armv/pgtable.h for more information. 132 */ 133 void __iomem * 134 __ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size, 135 unsigned long flags) 136 { 137 unsigned long addr; 138 struct vm_struct * area; 139 140 area = get_vm_area(size, VM_IOREMAP); 141 if (!area) 142 return NULL; 143 addr = (unsigned long)area->addr; 144 if (remap_area_pages(addr, pfn, size, flags)) { 145 vfree(addr); 146 return NULL; 147 } 148 return (void __iomem *) (offset + (char *)addr); 149 } 150 EXPORT_SYMBOL(__ioremap_pfn); 151 152 void __iomem * 153 __ioremap(unsigned long phys_addr, size_t size, unsigned long flags) 154 { 155 unsigned long last_addr; 156 unsigned long offset = phys_addr & ~PAGE_MASK; 157 unsigned long pfn = __phys_to_pfn(phys_addr); 158 159 /* 160 * Don't allow wraparound or zero size 161 */ 162 last_addr = phys_addr + size - 1; 163 if (!size || last_addr < phys_addr) 164 return NULL; 165 166 /* 167 * Page align the mapping size 168 */ 169 size = PAGE_ALIGN(last_addr + 1) - phys_addr; 170 171 return __ioremap_pfn(pfn, offset, size, flags); 172 } 173 EXPORT_SYMBOL(__ioremap); 174 175 void __iounmap(void __iomem *addr) 176 { 177 vfree((void *) (PAGE_MASK & (unsigned long) addr)); 178 } 179 EXPORT_SYMBOL(__iounmap); 180 181 #ifdef __io 182 void __iomem *ioport_map(unsigned long port, unsigned int nr) 183 { 184 return __io(port); 185 } 186 EXPORT_SYMBOL(ioport_map); 187 188 void ioport_unmap(void __iomem *addr) 189 { 190 } 191 EXPORT_SYMBOL(ioport_unmap); 192 #endif 193 194 #ifdef CONFIG_PCI 195 #include <linux/pci.h> 196 #include <linux/ioport.h> 197 198 void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen) 199 { 200 unsigned long start = pci_resource_start(dev, bar); 201 unsigned long len = pci_resource_len(dev, bar); 202 unsigned long flags = pci_resource_flags(dev, bar); 203 204 if (!len || !start) 205 return NULL; 206 if (maxlen && len > maxlen) 207 len = maxlen; 208 if (flags & IORESOURCE_IO) 209 return ioport_map(start, len); 210 if (flags & IORESOURCE_MEM) { 211 if (flags & IORESOURCE_CACHEABLE) 212 return ioremap(start, len); 213 return ioremap_nocache(start, len); 214 } 215 return NULL; 216 } 217 EXPORT_SYMBOL(pci_iomap); 218 219 void pci_iounmap(struct pci_dev *dev, void __iomem *addr) 220 { 221 if ((unsigned long)addr >= VMALLOC_START && 222 (unsigned long)addr < VMALLOC_END) 223 iounmap(addr); 224 } 225 EXPORT_SYMBOL(pci_iounmap); 226 #endif 227