Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * arch/sh/mm/ioremap.c |
| 3 | * |
| 4 | * Re-map IO memory to kernel address space so that we can access it. |
| 5 | * This is needed for high PCI addresses that aren't mapped in the |
| 6 | * 640k-1MB IO memory area on PC's |
| 7 | * |
| 8 | * (C) Copyright 1995 1996 Linus Torvalds |
| 9 | */ |
| 10 | |
| 11 | #include <linux/vmalloc.h> |
| 12 | #include <linux/mm.h> |
| 13 | #include <asm/io.h> |
| 14 | #include <asm/page.h> |
| 15 | #include <asm/pgalloc.h> |
| 16 | #include <asm/cacheflush.h> |
| 17 | #include <asm/tlbflush.h> |
| 18 | |
| 19 | static inline void remap_area_pte(pte_t * pte, unsigned long address, |
| 20 | unsigned long size, unsigned long phys_addr, unsigned long flags) |
| 21 | { |
| 22 | unsigned long end; |
| 23 | unsigned long pfn; |
| 24 | pgprot_t pgprot = __pgprot(_PAGE_PRESENT | _PAGE_RW | |
| 25 | _PAGE_DIRTY | _PAGE_ACCESSED | |
| 26 | _PAGE_HW_SHARED | _PAGE_FLAGS_HARD | flags); |
| 27 | |
| 28 | address &= ~PMD_MASK; |
| 29 | end = address + size; |
| 30 | if (end > PMD_SIZE) |
| 31 | end = PMD_SIZE; |
| 32 | if (address >= end) |
| 33 | BUG(); |
| 34 | pfn = phys_addr >> PAGE_SHIFT; |
| 35 | do { |
| 36 | if (!pte_none(*pte)) { |
| 37 | printk("remap_area_pte: page already exists\n"); |
| 38 | BUG(); |
| 39 | } |
| 40 | set_pte(pte, pfn_pte(pfn, pgprot)); |
| 41 | address += PAGE_SIZE; |
| 42 | pfn++; |
| 43 | pte++; |
| 44 | } while (address && (address < end)); |
| 45 | } |
| 46 | |
| 47 | static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, |
| 48 | unsigned long size, unsigned long phys_addr, unsigned long flags) |
| 49 | { |
| 50 | unsigned long end; |
| 51 | |
| 52 | address &= ~PGDIR_MASK; |
| 53 | end = address + size; |
| 54 | if (end > PGDIR_SIZE) |
| 55 | end = PGDIR_SIZE; |
| 56 | phys_addr -= address; |
| 57 | if (address >= end) |
| 58 | BUG(); |
| 59 | do { |
| 60 | pte_t * pte = pte_alloc_kernel(&init_mm, pmd, address); |
| 61 | if (!pte) |
| 62 | return -ENOMEM; |
| 63 | remap_area_pte(pte, address, end - address, address + phys_addr, flags); |
| 64 | address = (address + PMD_SIZE) & PMD_MASK; |
| 65 | pmd++; |
| 66 | } while (address && (address < end)); |
| 67 | return 0; |
| 68 | } |
| 69 | |
| 70 | int remap_area_pages(unsigned long address, unsigned long phys_addr, |
| 71 | unsigned long size, unsigned long flags) |
| 72 | { |
| 73 | int error; |
| 74 | pgd_t * dir; |
| 75 | unsigned long end = address + size; |
| 76 | |
| 77 | phys_addr -= address; |
| 78 | dir = pgd_offset_k(address); |
| 79 | flush_cache_all(); |
| 80 | if (address >= end) |
| 81 | BUG(); |
| 82 | spin_lock(&init_mm.page_table_lock); |
| 83 | do { |
| 84 | pmd_t *pmd; |
| 85 | pmd = pmd_alloc(&init_mm, dir, address); |
| 86 | error = -ENOMEM; |
| 87 | if (!pmd) |
| 88 | break; |
| 89 | if (remap_area_pmd(pmd, address, end - address, |
| 90 | phys_addr + address, flags)) |
| 91 | break; |
| 92 | error = 0; |
| 93 | address = (address + PGDIR_SIZE) & PGDIR_MASK; |
| 94 | dir++; |
| 95 | } while (address && (address < end)); |
| 96 | spin_unlock(&init_mm.page_table_lock); |
| 97 | flush_tlb_all(); |
| 98 | return error; |
| 99 | } |
| 100 | |
| 101 | /* |
| 102 | * Generic mapping function (not visible outside): |
| 103 | */ |
| 104 | |
| 105 | /* |
| 106 | * Remap an arbitrary physical address space into the kernel virtual |
| 107 | * address space. Needed when the kernel wants to access high addresses |
| 108 | * directly. |
| 109 | * |
| 110 | * NOTE! We need to allow non-page-aligned mappings too: we will obviously |
| 111 | * have to convert them into an offset in a page-aligned mapping, but the |
| 112 | * caller shouldn't need to know that small detail. |
| 113 | */ |
| 114 | void * p3_ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags) |
| 115 | { |
| 116 | void * addr; |
| 117 | struct vm_struct * area; |
| 118 | unsigned long offset, last_addr; |
| 119 | |
| 120 | /* Don't allow wraparound or zero size */ |
| 121 | last_addr = phys_addr + size - 1; |
| 122 | if (!size || last_addr < phys_addr) |
| 123 | return NULL; |
| 124 | |
| 125 | /* |
| 126 | * Don't remap the low PCI/ISA area, it's always mapped.. |
| 127 | */ |
| 128 | if (phys_addr >= 0xA0000 && last_addr < 0x100000) |
| 129 | return phys_to_virt(phys_addr); |
| 130 | |
| 131 | /* |
| 132 | * Don't allow anybody to remap normal RAM that we're using.. |
| 133 | */ |
| 134 | if (phys_addr < virt_to_phys(high_memory)) |
| 135 | return NULL; |
| 136 | |
| 137 | /* |
| 138 | * Mappings have to be page-aligned |
| 139 | */ |
| 140 | offset = phys_addr & ~PAGE_MASK; |
| 141 | phys_addr &= PAGE_MASK; |
| 142 | size = PAGE_ALIGN(last_addr+1) - phys_addr; |
| 143 | |
| 144 | /* |
| 145 | * Ok, go for it.. |
| 146 | */ |
| 147 | area = get_vm_area(size, VM_IOREMAP); |
| 148 | if (!area) |
| 149 | return NULL; |
| 150 | area->phys_addr = phys_addr; |
| 151 | addr = area->addr; |
| 152 | if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) { |
| 153 | vunmap(addr); |
| 154 | return NULL; |
| 155 | } |
| 156 | return (void *) (offset + (char *)addr); |
| 157 | } |
| 158 | |
| 159 | void p3_iounmap(void *addr) |
| 160 | { |
| 161 | if (addr > high_memory) |
| 162 | vfree((void *)(PAGE_MASK & (unsigned long)addr)); |
| 163 | } |