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 } 164