1 /* 2 * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch> 3 * Copyright (C) 2009 Wind River Systems Inc 4 * Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com 5 * Copyright (C) 2004 Microtronix Datacom Ltd. 6 * 7 * This file is subject to the terms and conditions of the GNU General Public 8 * License. See the file "COPYING" in the main directory of this archive 9 * for more details. 10 */ 11 12 #include <linux/export.h> 13 #include <linux/sched.h> 14 #include <linux/mm.h> 15 #include <linux/slab.h> 16 #include <linux/vmalloc.h> 17 #include <linux/io.h> 18 19 #include <asm/cacheflush.h> 20 #include <asm/tlbflush.h> 21 22 static inline void remap_area_pte(pte_t *pte, unsigned long address, 23 unsigned long size, unsigned long phys_addr, 24 unsigned long flags) 25 { 26 unsigned long end; 27 unsigned long pfn; 28 pgprot_t pgprot = __pgprot(_PAGE_GLOBAL | _PAGE_PRESENT | _PAGE_READ 29 | _PAGE_WRITE | flags); 30 31 address &= ~PMD_MASK; 32 end = address + size; 33 if (end > PMD_SIZE) 34 end = PMD_SIZE; 35 if (address >= end) 36 BUG(); 37 pfn = PFN_DOWN(phys_addr); 38 do { 39 if (!pte_none(*pte)) { 40 pr_err("remap_area_pte: page already exists\n"); 41 BUG(); 42 } 43 set_pte(pte, pfn_pte(pfn, pgprot)); 44 address += PAGE_SIZE; 45 pfn++; 46 pte++; 47 } while (address && (address < end)); 48 } 49 50 static inline int remap_area_pmd(pmd_t *pmd, unsigned long address, 51 unsigned long size, unsigned long phys_addr, 52 unsigned long flags) 53 { 54 unsigned long end; 55 56 address &= ~PGDIR_MASK; 57 end = address + size; 58 if (end > PGDIR_SIZE) 59 end = PGDIR_SIZE; 60 phys_addr -= address; 61 if (address >= end) 62 BUG(); 63 do { 64 pte_t *pte = pte_alloc_kernel(pmd, address); 65 66 if (!pte) 67 return -ENOMEM; 68 remap_area_pte(pte, address, end - address, address + phys_addr, 69 flags); 70 address = (address + PMD_SIZE) & PMD_MASK; 71 pmd++; 72 } while (address && (address < end)); 73 return 0; 74 } 75 76 static int remap_area_pages(unsigned long address, unsigned long phys_addr, 77 unsigned long size, unsigned long flags) 78 { 79 int error; 80 pgd_t *dir; 81 unsigned long end = address + size; 82 83 phys_addr -= address; 84 dir = pgd_offset(&init_mm, address); 85 flush_cache_all(); 86 if (address >= end) 87 BUG(); 88 do { 89 p4d_t *p4d; 90 pud_t *pud; 91 pmd_t *pmd; 92 93 error = -ENOMEM; 94 p4d = p4d_alloc(&init_mm, dir, address); 95 if (!p4d) 96 break; 97 pud = pud_alloc(&init_mm, p4d, address); 98 if (!pud) 99 break; 100 pmd = pmd_alloc(&init_mm, pud, address); 101 if (!pmd) 102 break; 103 if (remap_area_pmd(pmd, address, end - address, 104 phys_addr + address, flags)) 105 break; 106 error = 0; 107 address = (address + PGDIR_SIZE) & PGDIR_MASK; 108 dir++; 109 } while (address && (address < end)); 110 flush_tlb_all(); 111 return error; 112 } 113 114 #define IS_MAPPABLE_UNCACHEABLE(addr) (addr < 0x20000000UL) 115 116 /* 117 * Map some physical address range into the kernel address space. 118 */ 119 void __iomem *ioremap(unsigned long phys_addr, unsigned long size) 120 { 121 struct vm_struct *area; 122 unsigned long offset; 123 unsigned long last_addr; 124 void *addr; 125 126 /* Don't allow wraparound or zero size */ 127 last_addr = phys_addr + size - 1; 128 129 if (!size || last_addr < phys_addr) 130 return NULL; 131 132 /* Don't allow anybody to remap normal RAM that we're using */ 133 if (phys_addr > PHYS_OFFSET && phys_addr < virt_to_phys(high_memory)) { 134 char *t_addr, *t_end; 135 struct page *page; 136 137 t_addr = __va(phys_addr); 138 t_end = t_addr + (size - 1); 139 for (page = virt_to_page(t_addr); 140 page <= virt_to_page(t_end); page++) 141 if (!PageReserved(page)) 142 return NULL; 143 } 144 145 /* 146 * Map uncached objects in the low part of address space to 147 * CONFIG_NIOS2_IO_REGION_BASE 148 */ 149 if (IS_MAPPABLE_UNCACHEABLE(phys_addr) && 150 IS_MAPPABLE_UNCACHEABLE(last_addr)) 151 return (void __iomem *)(CONFIG_NIOS2_IO_REGION_BASE + phys_addr); 152 153 /* Mappings have to be page-aligned */ 154 offset = phys_addr & ~PAGE_MASK; 155 phys_addr &= PAGE_MASK; 156 size = PAGE_ALIGN(last_addr + 1) - phys_addr; 157 158 /* Ok, go for it */ 159 area = get_vm_area(size, VM_IOREMAP); 160 if (!area) 161 return NULL; 162 addr = area->addr; 163 if (remap_area_pages((unsigned long) addr, phys_addr, size, 0)) { 164 vunmap(addr); 165 return NULL; 166 } 167 return (void __iomem *) (offset + (char *)addr); 168 } 169 EXPORT_SYMBOL(ioremap); 170 171 /* 172 * iounmap unmaps nearly everything, so be careful 173 * it doesn't free currently pointer/page tables anymore but it 174 * wasn't used anyway and might be added later. 175 */ 176 void iounmap(void __iomem *addr) 177 { 178 struct vm_struct *p; 179 180 if ((unsigned long) addr > CONFIG_NIOS2_IO_REGION_BASE) 181 return; 182 183 p = remove_vm_area((void *) (PAGE_MASK & (unsigned long __force) addr)); 184 if (!p) 185 pr_err("iounmap: bad address %p\n", addr); 186 kfree(p); 187 } 188 EXPORT_SYMBOL(iounmap); 189