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(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 do { 83 pmd_t *pmd; 84 pmd = pmd_alloc(&init_mm, dir, address); 85 error = -ENOMEM; 86 if (!pmd) 87 break; 88 if (remap_area_pmd(pmd, address, end - address, 89 phys_addr + address, flags)) 90 break; 91 error = 0; 92 address = (address + PGDIR_SIZE) & PGDIR_MASK; 93 dir++; 94 } while (address && (address < end)); 95 flush_tlb_all(); 96 return error; 97 } 98 99 /* 100 * Generic mapping function (not visible outside): 101 */ 102 103 /* 104 * Remap an arbitrary physical address space into the kernel virtual 105 * address space. Needed when the kernel wants to access high addresses 106 * directly. 107 * 108 * NOTE! We need to allow non-page-aligned mappings too: we will obviously 109 * have to convert them into an offset in a page-aligned mapping, but the 110 * caller shouldn't need to know that small detail. 111 */ 112 void * p3_ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags) 113 { 114 void * addr; 115 struct vm_struct * area; 116 unsigned long offset, last_addr; 117 118 /* Don't allow wraparound or zero size */ 119 last_addr = phys_addr + size - 1; 120 if (!size || last_addr < phys_addr) 121 return NULL; 122 123 /* 124 * Don't remap the low PCI/ISA area, it's always mapped.. 125 */ 126 if (phys_addr >= 0xA0000 && last_addr < 0x100000) 127 return phys_to_virt(phys_addr); 128 129 /* 130 * Don't allow anybody to remap normal RAM that we're using.. 131 */ 132 if (phys_addr < virt_to_phys(high_memory)) 133 return NULL; 134 135 /* 136 * Mappings have to be page-aligned 137 */ 138 offset = phys_addr & ~PAGE_MASK; 139 phys_addr &= PAGE_MASK; 140 size = PAGE_ALIGN(last_addr+1) - phys_addr; 141 142 /* 143 * Ok, go for it.. 144 */ 145 area = get_vm_area(size, VM_IOREMAP); 146 if (!area) 147 return NULL; 148 area->phys_addr = phys_addr; 149 addr = area->addr; 150 if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) { 151 vunmap(addr); 152 return NULL; 153 } 154 return (void *) (offset + (char *)addr); 155 } 156 157 void p3_iounmap(void *addr) 158 { 159 if (addr > high_memory) 160 vfree((void *)(PAGE_MASK & (unsigned long)addr)); 161 } 162