1 /* 2 * Re-map IO memory to kernel address space so that we can access it. 3 * This is needed for high PCI addresses that aren't mapped in the 4 * 640k-1MB IO memory area on PC's 5 * 6 * (C) Copyright 1995 1996 Linus Torvalds 7 */ 8 9 #include <linux/bootmem.h> 10 #include <linux/init.h> 11 #include <linux/io.h> 12 #include <linux/module.h> 13 #include <linux/slab.h> 14 #include <linux/vmalloc.h> 15 #include <linux/mmiotrace.h> 16 17 #include <asm/cacheflush.h> 18 #include <asm/e820.h> 19 #include <asm/fixmap.h> 20 #include <asm/pgtable.h> 21 #include <asm/tlbflush.h> 22 #include <asm/pgalloc.h> 23 #include <asm/pat.h> 24 25 #include "physaddr.h" 26 27 /* 28 * Fix up the linear direct mapping of the kernel to avoid cache attribute 29 * conflicts. 30 */ 31 int ioremap_change_attr(unsigned long vaddr, unsigned long size, 32 unsigned long prot_val) 33 { 34 unsigned long nrpages = size >> PAGE_SHIFT; 35 int err; 36 37 switch (prot_val) { 38 case _PAGE_CACHE_UC: 39 default: 40 err = _set_memory_uc(vaddr, nrpages); 41 break; 42 case _PAGE_CACHE_WC: 43 err = _set_memory_wc(vaddr, nrpages); 44 break; 45 case _PAGE_CACHE_WB: 46 err = _set_memory_wb(vaddr, nrpages); 47 break; 48 } 49 50 return err; 51 } 52 53 /* 54 * Remap an arbitrary physical address space into the kernel virtual 55 * address space. Needed when the kernel wants to access high addresses 56 * directly. 57 * 58 * NOTE! We need to allow non-page-aligned mappings too: we will obviously 59 * have to convert them into an offset in a page-aligned mapping, but the 60 * caller shouldn't need to know that small detail. 61 */ 62 static void __iomem *__ioremap_caller(resource_size_t phys_addr, 63 unsigned long size, unsigned long prot_val, void *caller) 64 { 65 unsigned long offset, vaddr; 66 resource_size_t pfn, last_pfn, last_addr; 67 const resource_size_t unaligned_phys_addr = phys_addr; 68 const unsigned long unaligned_size = size; 69 struct vm_struct *area; 70 unsigned long new_prot_val; 71 pgprot_t prot; 72 int retval; 73 void __iomem *ret_addr; 74 75 /* Don't allow wraparound or zero size */ 76 last_addr = phys_addr + size - 1; 77 if (!size || last_addr < phys_addr) 78 return NULL; 79 80 if (!phys_addr_valid(phys_addr)) { 81 printk(KERN_WARNING "ioremap: invalid physical address %llx\n", 82 (unsigned long long)phys_addr); 83 WARN_ON_ONCE(1); 84 return NULL; 85 } 86 87 /* 88 * Don't remap the low PCI/ISA area, it's always mapped.. 89 */ 90 if (is_ISA_range(phys_addr, last_addr)) 91 return (__force void __iomem *)phys_to_virt(phys_addr); 92 93 /* 94 * Don't allow anybody to remap normal RAM that we're using.. 95 */ 96 last_pfn = last_addr >> PAGE_SHIFT; 97 for (pfn = phys_addr >> PAGE_SHIFT; pfn <= last_pfn; pfn++) { 98 int is_ram = page_is_ram(pfn); 99 100 if (is_ram && pfn_valid(pfn) && !PageReserved(pfn_to_page(pfn))) 101 return NULL; 102 WARN_ON_ONCE(is_ram); 103 } 104 105 /* 106 * Mappings have to be page-aligned 107 */ 108 offset = phys_addr & ~PAGE_MASK; 109 phys_addr &= PHYSICAL_PAGE_MASK; 110 size = PAGE_ALIGN(last_addr+1) - phys_addr; 111 112 retval = reserve_memtype(phys_addr, (u64)phys_addr + size, 113 prot_val, &new_prot_val); 114 if (retval) { 115 printk(KERN_ERR "ioremap reserve_memtype failed %d\n", retval); 116 return NULL; 117 } 118 119 if (prot_val != new_prot_val) { 120 if (!is_new_memtype_allowed(phys_addr, size, 121 prot_val, new_prot_val)) { 122 printk(KERN_ERR 123 "ioremap error for 0x%llx-0x%llx, requested 0x%lx, got 0x%lx\n", 124 (unsigned long long)phys_addr, 125 (unsigned long long)(phys_addr + size), 126 prot_val, new_prot_val); 127 goto err_free_memtype; 128 } 129 prot_val = new_prot_val; 130 } 131 132 switch (prot_val) { 133 case _PAGE_CACHE_UC: 134 default: 135 prot = PAGE_KERNEL_IO_NOCACHE; 136 break; 137 case _PAGE_CACHE_UC_MINUS: 138 prot = PAGE_KERNEL_IO_UC_MINUS; 139 break; 140 case _PAGE_CACHE_WC: 141 prot = PAGE_KERNEL_IO_WC; 142 break; 143 case _PAGE_CACHE_WB: 144 prot = PAGE_KERNEL_IO; 145 break; 146 } 147 148 /* 149 * Ok, go for it.. 150 */ 151 area = get_vm_area_caller(size, VM_IOREMAP, caller); 152 if (!area) 153 goto err_free_memtype; 154 area->phys_addr = phys_addr; 155 vaddr = (unsigned long) area->addr; 156 157 if (kernel_map_sync_memtype(phys_addr, size, prot_val)) 158 goto err_free_area; 159 160 if (ioremap_page_range(vaddr, vaddr + size, phys_addr, prot)) 161 goto err_free_area; 162 163 ret_addr = (void __iomem *) (vaddr + offset); 164 mmiotrace_ioremap(unaligned_phys_addr, unaligned_size, ret_addr); 165 166 /* 167 * Check if the request spans more than any BAR in the iomem resource 168 * tree. 169 */ 170 WARN_ONCE(iomem_map_sanity_check(unaligned_phys_addr, unaligned_size), 171 KERN_INFO "Info: mapping multiple BARs. Your kernel is fine."); 172 173 return ret_addr; 174 err_free_area: 175 free_vm_area(area); 176 err_free_memtype: 177 free_memtype(phys_addr, phys_addr + size); 178 return NULL; 179 } 180 181 /** 182 * ioremap_nocache - map bus memory into CPU space 183 * @phys_addr: bus address of the memory 184 * @size: size of the resource to map 185 * 186 * ioremap_nocache performs a platform specific sequence of operations to 187 * make bus memory CPU accessible via the readb/readw/readl/writeb/ 188 * writew/writel functions and the other mmio helpers. The returned 189 * address is not guaranteed to be usable directly as a virtual 190 * address. 191 * 192 * This version of ioremap ensures that the memory is marked uncachable 193 * on the CPU as well as honouring existing caching rules from things like 194 * the PCI bus. Note that there are other caches and buffers on many 195 * busses. In particular driver authors should read up on PCI writes 196 * 197 * It's useful if some control registers are in such an area and 198 * write combining or read caching is not desirable: 199 * 200 * Must be freed with iounmap. 201 */ 202 void __iomem *ioremap_nocache(resource_size_t phys_addr, unsigned long size) 203 { 204 /* 205 * Ideally, this should be: 206 * pat_enabled ? _PAGE_CACHE_UC : _PAGE_CACHE_UC_MINUS; 207 * 208 * Till we fix all X drivers to use ioremap_wc(), we will use 209 * UC MINUS. 210 */ 211 unsigned long val = _PAGE_CACHE_UC_MINUS; 212 213 return __ioremap_caller(phys_addr, size, val, 214 __builtin_return_address(0)); 215 } 216 EXPORT_SYMBOL(ioremap_nocache); 217 218 /** 219 * ioremap_wc - map memory into CPU space write combined 220 * @phys_addr: bus address of the memory 221 * @size: size of the resource to map 222 * 223 * This version of ioremap ensures that the memory is marked write combining. 224 * Write combining allows faster writes to some hardware devices. 225 * 226 * Must be freed with iounmap. 227 */ 228 void __iomem *ioremap_wc(resource_size_t phys_addr, unsigned long size) 229 { 230 if (pat_enabled) 231 return __ioremap_caller(phys_addr, size, _PAGE_CACHE_WC, 232 __builtin_return_address(0)); 233 else 234 return ioremap_nocache(phys_addr, size); 235 } 236 EXPORT_SYMBOL(ioremap_wc); 237 238 void __iomem *ioremap_cache(resource_size_t phys_addr, unsigned long size) 239 { 240 return __ioremap_caller(phys_addr, size, _PAGE_CACHE_WB, 241 __builtin_return_address(0)); 242 } 243 EXPORT_SYMBOL(ioremap_cache); 244 245 void __iomem *ioremap_prot(resource_size_t phys_addr, unsigned long size, 246 unsigned long prot_val) 247 { 248 return __ioremap_caller(phys_addr, size, (prot_val & _PAGE_CACHE_MASK), 249 __builtin_return_address(0)); 250 } 251 EXPORT_SYMBOL(ioremap_prot); 252 253 /** 254 * iounmap - Free a IO remapping 255 * @addr: virtual address from ioremap_* 256 * 257 * Caller must ensure there is only one unmapping for the same pointer. 258 */ 259 void iounmap(volatile void __iomem *addr) 260 { 261 struct vm_struct *p, *o; 262 263 if ((void __force *)addr <= high_memory) 264 return; 265 266 /* 267 * __ioremap special-cases the PCI/ISA range by not instantiating a 268 * vm_area and by simply returning an address into the kernel mapping 269 * of ISA space. So handle that here. 270 */ 271 if ((void __force *)addr >= phys_to_virt(ISA_START_ADDRESS) && 272 (void __force *)addr < phys_to_virt(ISA_END_ADDRESS)) 273 return; 274 275 addr = (volatile void __iomem *) 276 (PAGE_MASK & (unsigned long __force)addr); 277 278 mmiotrace_iounmap(addr); 279 280 /* Use the vm area unlocked, assuming the caller 281 ensures there isn't another iounmap for the same address 282 in parallel. Reuse of the virtual address is prevented by 283 leaving it in the global lists until we're done with it. 284 cpa takes care of the direct mappings. */ 285 p = find_vm_area((void __force *)addr); 286 287 if (!p) { 288 printk(KERN_ERR "iounmap: bad address %p\n", addr); 289 dump_stack(); 290 return; 291 } 292 293 free_memtype(p->phys_addr, p->phys_addr + get_vm_area_size(p)); 294 295 /* Finally remove it */ 296 o = remove_vm_area((void __force *)addr); 297 BUG_ON(p != o || o == NULL); 298 kfree(p); 299 } 300 EXPORT_SYMBOL(iounmap); 301 302 /* 303 * Convert a physical pointer to a virtual kernel pointer for /dev/mem 304 * access 305 */ 306 void *xlate_dev_mem_ptr(unsigned long phys) 307 { 308 void *addr; 309 unsigned long start = phys & PAGE_MASK; 310 311 /* If page is RAM, we can use __va. Otherwise ioremap and unmap. */ 312 if (page_is_ram(start >> PAGE_SHIFT)) 313 return __va(phys); 314 315 addr = (void __force *)ioremap_cache(start, PAGE_SIZE); 316 if (addr) 317 addr = (void *)((unsigned long)addr | (phys & ~PAGE_MASK)); 318 319 return addr; 320 } 321 322 void unxlate_dev_mem_ptr(unsigned long phys, void *addr) 323 { 324 if (page_is_ram(phys >> PAGE_SHIFT)) 325 return; 326 327 iounmap((void __iomem *)((unsigned long)addr & PAGE_MASK)); 328 return; 329 } 330 331 static pte_t bm_pte[PAGE_SIZE/sizeof(pte_t)] __page_aligned_bss; 332 333 static inline pmd_t * __init early_ioremap_pmd(unsigned long addr) 334 { 335 /* Don't assume we're using swapper_pg_dir at this point */ 336 pgd_t *base = __va(read_cr3()); 337 pgd_t *pgd = &base[pgd_index(addr)]; 338 pud_t *pud = pud_offset(pgd, addr); 339 pmd_t *pmd = pmd_offset(pud, addr); 340 341 return pmd; 342 } 343 344 static inline pte_t * __init early_ioremap_pte(unsigned long addr) 345 { 346 return &bm_pte[pte_index(addr)]; 347 } 348 349 bool __init is_early_ioremap_ptep(pte_t *ptep) 350 { 351 return ptep >= &bm_pte[0] && ptep < &bm_pte[PAGE_SIZE/sizeof(pte_t)]; 352 } 353 354 void __init early_ioremap_init(void) 355 { 356 pmd_t *pmd; 357 358 early_ioremap_setup(); 359 360 pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)); 361 memset(bm_pte, 0, sizeof(bm_pte)); 362 pmd_populate_kernel(&init_mm, pmd, bm_pte); 363 364 /* 365 * The boot-ioremap range spans multiple pmds, for which 366 * we are not prepared: 367 */ 368 #define __FIXADDR_TOP (-PAGE_SIZE) 369 BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT) 370 != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT)); 371 #undef __FIXADDR_TOP 372 if (pmd != early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END))) { 373 WARN_ON(1); 374 printk(KERN_WARNING "pmd %p != %p\n", 375 pmd, early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END))); 376 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n", 377 fix_to_virt(FIX_BTMAP_BEGIN)); 378 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_END): %08lx\n", 379 fix_to_virt(FIX_BTMAP_END)); 380 381 printk(KERN_WARNING "FIX_BTMAP_END: %d\n", FIX_BTMAP_END); 382 printk(KERN_WARNING "FIX_BTMAP_BEGIN: %d\n", 383 FIX_BTMAP_BEGIN); 384 } 385 } 386 387 void __init __early_set_fixmap(enum fixed_addresses idx, 388 phys_addr_t phys, pgprot_t flags) 389 { 390 unsigned long addr = __fix_to_virt(idx); 391 pte_t *pte; 392 393 if (idx >= __end_of_fixed_addresses) { 394 BUG(); 395 return; 396 } 397 pte = early_ioremap_pte(addr); 398 399 if (pgprot_val(flags)) 400 set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags)); 401 else 402 pte_clear(&init_mm, addr, pte); 403 __flush_tlb_one(addr); 404 } 405