1 /* 2 * Re-map IO memory to kernel address space so that we can access it. 3 * 4 * These functions should only be used when it is necessary to map a 5 * physical address space into the kernel address space before ioremap() 6 * can be used, e.g. early in boot before paging_init(). 7 * 8 * Copyright (C) 2009 Matt Fleming 9 */ 10 11 #include <linux/vmalloc.h> 12 #include <linux/ioport.h> 13 #include <linux/module.h> 14 #include <linux/mm.h> 15 #include <linux/io.h> 16 #include <linux/bootmem.h> 17 #include <linux/proc_fs.h> 18 #include <asm/fixmap.h> 19 #include <asm/page.h> 20 #include <asm/pgalloc.h> 21 #include <asm/addrspace.h> 22 #include <asm/cacheflush.h> 23 #include <asm/tlbflush.h> 24 #include <asm/mmu.h> 25 #include <asm/mmu_context.h> 26 27 struct ioremap_map { 28 void __iomem *addr; 29 unsigned long size; 30 unsigned long fixmap_addr; 31 }; 32 33 static struct ioremap_map ioremap_maps[FIX_N_IOREMAPS]; 34 35 void __init ioremap_fixed_init(void) 36 { 37 struct ioremap_map *map; 38 int i; 39 40 for (i = 0; i < FIX_N_IOREMAPS; i++) { 41 map = &ioremap_maps[i]; 42 map->fixmap_addr = __fix_to_virt(FIX_IOREMAP_BEGIN + i); 43 } 44 } 45 46 void __init __iomem * 47 ioremap_fixed(phys_addr_t phys_addr, unsigned long size, pgprot_t prot) 48 { 49 enum fixed_addresses idx0, idx; 50 struct ioremap_map *map; 51 unsigned int nrpages; 52 unsigned long offset; 53 int i, slot; 54 55 /* 56 * Mappings have to be page-aligned 57 */ 58 offset = phys_addr & ~PAGE_MASK; 59 phys_addr &= PAGE_MASK; 60 size = PAGE_ALIGN(phys_addr + size) - phys_addr; 61 62 slot = -1; 63 for (i = 0; i < FIX_N_IOREMAPS; i++) { 64 map = &ioremap_maps[i]; 65 if (!map->addr) { 66 map->size = size; 67 slot = i; 68 break; 69 } 70 } 71 72 if (slot < 0) 73 return NULL; 74 75 /* 76 * Mappings have to fit in the FIX_IOREMAP area. 77 */ 78 nrpages = size >> PAGE_SHIFT; 79 if (nrpages > FIX_N_IOREMAPS) 80 return NULL; 81 82 /* 83 * Ok, go for it.. 84 */ 85 idx0 = FIX_IOREMAP_BEGIN + slot; 86 idx = idx0; 87 while (nrpages > 0) { 88 pgprot_val(prot) |= _PAGE_WIRED; 89 __set_fixmap(idx, phys_addr, prot); 90 phys_addr += PAGE_SIZE; 91 idx++; 92 --nrpages; 93 } 94 95 map->addr = (void __iomem *)(offset + map->fixmap_addr); 96 return map->addr; 97 } 98 99 int iounmap_fixed(void __iomem *addr) 100 { 101 enum fixed_addresses idx; 102 struct ioremap_map *map; 103 unsigned int nrpages; 104 int i, slot; 105 106 slot = -1; 107 for (i = 0; i < FIX_N_IOREMAPS; i++) { 108 map = &ioremap_maps[i]; 109 if (map->addr == addr) { 110 slot = i; 111 break; 112 } 113 } 114 115 /* 116 * If we don't match, it's not for us. 117 */ 118 if (slot < 0) 119 return -EINVAL; 120 121 nrpages = map->size >> PAGE_SHIFT; 122 123 idx = FIX_IOREMAP_BEGIN + slot + nrpages - 1; 124 while (nrpages > 0) { 125 __clear_fixmap(idx, __pgprot(_PAGE_WIRED)); 126 --idx; 127 --nrpages; 128 } 129 130 map->size = 0; 131 map->addr = NULL; 132 133 return 0; 134 } 135