include/asm-mips/io.h

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 1994, 1995 Waldorf GmbH
   7  * Copyright (C) 1994 - 2000, 06 Ralf Baechle
   8  * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
   9  * Copyright (C) 2004, 2005  MIPS Technologies, Inc.  All rights reserved.
  10  *      Author: Maciej W. Rozycki <macro@mips.com>
  11  */
  12 #ifndef _ASM_IO_H
  13 #define _ASM_IO_H
  14
  15 #include <linux/compiler.h>
  16 #include <linux/kernel.h>
  17 #include <linux/types.h>
  18
  19 #include <asm/addrspace.h>
  20 #include <asm/byteorder.h>
  21 #include <asm/cpu.h>
  22 #include <asm/cpu-features.h>
  23 #include <asm-generic/iomap.h>
  24 #include <asm/page.h>
  25 #include <asm/pgtable-bits.h>
  26 #include <asm/processor.h>
  27 #include <asm/string.h>
  28
  29 #include <ioremap.h>
  30 #include <mangle-port.h>
  31
  32 /*
  33  * Slowdown I/O port space accesses for antique hardware.
  34  */
  35 #undef CONF_SLOWDOWN_IO
  36
  37 /*
  38  * Raw operations are never swapped in software.  OTOH values that raw
  39  * operations are working on may or may not have been swapped by the bus
  40  * hardware.  An example use would be for flash memory that's used for
  41  * execute in place.
  42  */
  43 # define __raw_ioswabb(a,x)     (x)
  44 # define __raw_ioswabw(a,x)     (x)
  45 # define __raw_ioswabl(a,x)     (x)
  46 # define __raw_ioswabq(a,x)     (x)
  47 # define ____raw_ioswabq(a,x)   (x)
  48
  49 /* ioswab[bwlq], __mem_ioswab[bwlq] are defined in mangle-port.h */
  50
  51 #define IO_SPACE_LIMIT 0xffff
  52
  53 /*
  54  * On MIPS I/O ports are memory mapped, so we access them using normal
  55  * load/store instructions. mips_io_port_base is the virtual address to
  56  * which all ports are being mapped.  For sake of efficiency some code
  57  * assumes that this is an address that can be loaded with a single lui
  58  * instruction, so the lower 16 bits must be zero.  Should be true on
  59  * on any sane architecture; generic code does not use this assumption.
  60  */
  61 extern const unsigned long mips_io_port_base;
  62
  63 /*
  64  * Gcc will generate code to load the value of mips_io_port_base after each
  65  * function call which may be fairly wasteful in some cases.  So we don't
  66  * play quite by the book.  We tell gcc mips_io_port_base is a long variable
  67  * which solves the code generation issue.  Now we need to violate the
  68  * aliasing rules a little to make initialization possible and finally we
  69  * will need the barrier() to fight side effects of the aliasing chat.
  70  * This trickery will eventually collapse under gcc's optimizer.  Oh well.
  71  */
  72 static inline void set_io_port_base(unsigned long base)
  73 {
  74         * (unsigned long *) &mips_io_port_base = base;
  75         barrier();
  76 }
  77
  78 /*
  79  * Thanks to James van Artsdalen for a better timing-fix than
  80  * the two short jumps: using outb's to a nonexistent port seems
  81  * to guarantee better timings even on fast machines.
  82  *
  83  * On the other hand, I'd like to be sure of a non-existent port:
  84  * I feel a bit unsafe about using 0x80 (should be safe, though)
  85  *
  86  *              Linus
  87  *
  88  */
  89
  90 #define __SLOW_DOWN_IO \
  91         __asm__ __volatile__( \
  92                 "sb\t$0,0x80(%0)" \
  93                 : : "r" (mips_io_port_base));
  94
  95 #ifdef CONF_SLOWDOWN_IO
  96 #ifdef REALLY_SLOW_IO
  97 #define SLOW_DOWN_IO { __SLOW_DOWN_IO; __SLOW_DOWN_IO; __SLOW_DOWN_IO; __SLOW_DOWN_IO; }
  98 #else
  99 #define SLOW_DOWN_IO __SLOW_DOWN_IO
 100 #endif
 101 #else
 102 #define SLOW_DOWN_IO
 103 #endif
 104
 105 /*
 106  *     virt_to_phys    -       map virtual addresses to physical
 107  *     @address: address to remap
 108  *
 109  *     The returned physical address is the physical (CPU) mapping for
 110  *     the memory address given. It is only valid to use this function on
 111  *     addresses directly mapped or allocated via kmalloc.
 112  *
 113  *     This function does not give bus mappings for DMA transfers. In
 114  *     almost all conceivable cases a device driver should not be using
 115  *     this function
 116  */
 117 static inline unsigned long virt_to_phys(volatile const void *address)
 118 {
 119         return (unsigned long)address - PAGE_OFFSET + PHYS_OFFSET;
 120 }
 121
 122 /*
 123  *     phys_to_virt    -       map physical address to virtual
 124  *     @address: address to remap
 125  *
 126  *     The returned virtual address is a current CPU mapping for
 127  *     the memory address given. It is only valid to use this function on
 128  *     addresses that have a kernel mapping
 129  *
 130  *     This function does not handle bus mappings for DMA transfers. In
 131  *     almost all conceivable cases a device driver should not be using
 132  *     this function
 133  */
 134 static inline void * phys_to_virt(unsigned long address)
 135 {
 136         return (void *)(address + PAGE_OFFSET - PHYS_OFFSET);
 137 }
 138
 139 /*
 140  * ISA I/O bus memory addresses are 1:1 with the physical address.
 141  */
 142 static inline unsigned long isa_virt_to_bus(volatile void * address)
 143 {
 144         return (unsigned long)address - PAGE_OFFSET;
 145 }
 146
 147 static inline void * isa_bus_to_virt(unsigned long address)
 148 {
 149         return (void *)(address + PAGE_OFFSET);
 150 }
 151
 152 #define isa_page_to_bus page_to_phys
 153
 154 /*
 155  * However PCI ones are not necessarily 1:1 and therefore these interfaces
 156  * are forbidden in portable PCI drivers.
 157  *
 158  * Allow them for x86 for legacy drivers, though.
 159  */
 160 #define virt_to_bus virt_to_phys
 161 #define bus_to_virt phys_to_virt
 162
 163 /*
 164  * isa_slot_offset is the address where E(ISA) busaddress 0 is mapped
 165  * for the processor.  This implies the assumption that there is only
 166  * one of these busses.
 167  */
 168 extern unsigned long isa_slot_offset;
 169
 170 /*
 171  * Change "struct page" to physical address.
 172  */
 173 #define page_to_phys(page)      ((dma_addr_t)page_to_pfn(page) << PAGE_SHIFT)
 174
 175 extern void __iomem * __ioremap(phys_t offset, phys_t size, unsigned long flags);
 176 extern void __iounmap(const volatile void __iomem *addr);
 177
 178 static inline void __iomem * __ioremap_mode(phys_t offset, unsigned long size,
 179         unsigned long flags)
 180 {
 181 #define __IS_LOW512(addr) (!((phys_t)(addr) & (phys_t) ~0x1fffffffULL))
 182
 183         if (cpu_has_64bit_addresses) {
 184                 u64 base = UNCAC_BASE;
 185
 186                 /*
 187                  * R10000 supports a 2 bit uncached attribute therefore
 188                  * UNCAC_BASE may not equal IO_BASE.
 189                  */
 190                 if (flags == _CACHE_UNCACHED)
 191                         base = (u64) IO_BASE;
 192                 return (void __iomem *) (unsigned long) (base + offset);
 193         } else if (__builtin_constant_p(offset) &&
 194                    __builtin_constant_p(size) && __builtin_constant_p(flags)) {
 195                 phys_t phys_addr, last_addr;
 196
 197                 phys_addr = fixup_bigphys_addr(offset, size);
 198
 199                 /* Don't allow wraparound or zero size. */
 200                 last_addr = phys_addr + size - 1;
 201                 if (!size || last_addr < phys_addr)
 202                         return NULL;
 203
 204                 /*
 205                  * Map uncached objects in the low 512MB of address
 206                  * space using KSEG1.
 207                  */
 208                 if (__IS_LOW512(phys_addr) && __IS_LOW512(last_addr) &&
 209                     flags == _CACHE_UNCACHED)
 210                         return (void __iomem *)CKSEG1ADDR(phys_addr);
 211         }
 212
 213         return __ioremap(offset, size, flags);
 214
 215 #undef __IS_LOW512
 216 }
 217
 218 /*
 219  * ioremap     -   map bus memory into CPU space
 220  * @offset:    bus address of the memory
 221  * @size:      size of the resource to map
 222  *
 223  * ioremap performs a platform specific sequence of operations to
 224  * make bus memory CPU accessible via the readb/readw/readl/writeb/
 225  * writew/writel functions and the other mmio helpers. The returned
 226  * address is not guaranteed to be usable directly as a virtual
 227  * address.
 228  */
 229 #define ioremap(offset, size)                                           \
 230         __ioremap_mode((offset), (size), _CACHE_UNCACHED)
 231
 232 /*
 233  * ioremap_nocache     -   map bus memory into CPU space
 234  * @offset:    bus address of the memory
 235  * @size:      size of the resource to map
 236  *
 237  * ioremap_nocache performs a platform specific sequence of operations to
 238  * make bus memory CPU accessible via the readb/readw/readl/writeb/
 239  * writew/writel functions and the other mmio helpers. The returned
 240  * address is not guaranteed to be usable directly as a virtual
 241  * address.
 242  *
 243  * This version of ioremap ensures that the memory is marked uncachable
 244  * on the CPU as well as honouring existing caching rules from things like
 245  * the PCI bus. Note that there are other caches and buffers on many
 246  * busses. In paticular driver authors should read up on PCI writes
 247  *
 248  * It's useful if some control registers are in such an area and
 249  * write combining or read caching is not desirable:
 250  */
 251 #define ioremap_nocache(offset, size)                                   \
 252         __ioremap_mode((offset), (size), _CACHE_UNCACHED)
 253
 254 /*
 255  * ioremap_cachable -   map bus memory into CPU space
 256  * @offset:         bus address of the memory
 257  * @size:           size of the resource to map
 258  *
 259  * ioremap_nocache performs a platform specific sequence of operations to
 260  * make bus memory CPU accessible via the readb/readw/readl/writeb/
 261  * writew/writel functions and the other mmio helpers. The returned
 262  * address is not guaranteed to be usable directly as a virtual
 263  * address.
 264  *
 265  * This version of ioremap ensures that the memory is marked cachable by
 266  * the CPU.  Also enables full write-combining.  Useful for some
 267  * memory-like regions on I/O busses.
 268  */
 269 #define ioremap_cachable(offset, size)                                  \
 270         __ioremap_mode((offset), (size), PAGE_CACHABLE_DEFAULT)
 271
 272 /*
 273  * These two are MIPS specific ioremap variant.  ioremap_cacheable_cow
 274  * requests a cachable mapping, ioremap_uncached_accelerated requests a
 275  * mapping using the uncached accelerated mode which isn't supported on
 276  * all processors.
 277  */
 278 #define ioremap_cacheable_cow(offset, size)                             \
 279         __ioremap_mode((offset), (size), _CACHE_CACHABLE_COW)
 280 #define ioremap_uncached_accelerated(offset, size)                      \
 281         __ioremap_mode((offset), (size), _CACHE_UNCACHED_ACCELERATED)
 282
 283 static inline void iounmap(const volatile void __iomem *addr)
 284 {
 285 #define __IS_KSEG1(addr) (((unsigned long)(addr) & ~0x1fffffffUL) == CKSEG1)
 286
 287         if (cpu_has_64bit_addresses ||
 288             (__builtin_constant_p(addr) && __IS_KSEG1(addr)))
 289                 return;
 290
 291         __iounmap(addr);
 292
 293 #undef __IS_KSEG1
 294 }
 295
 296 #define __BUILD_MEMORY_SINGLE(pfx, bwlq, type, irq)                     \
 297                                                                         \
 298 static inline void pfx##write##bwlq(type val,                           \
 299                                     volatile void __iomem *mem)         \
 300 {                                                                       \
 301         volatile type *__mem;                                           \
 302         type __val;                                                     \
 303                                                                         \
 304         __mem = (void *)__swizzle_addr_##bwlq((unsigned long)(mem));    \
 305                                                                         \
 306         __val = pfx##ioswab##bwlq(__mem, val);                          \
 307                                                                         \
 308         if (sizeof(type) != sizeof(u64) || sizeof(u64) == sizeof(long)) \
 309                 *__mem = __val;                                         \
 310         else if (cpu_has_64bits) {                                      \
 311                 unsigned long __flags;                                  \
 312                 type __tmp;                                             \
 313                                                                         \
 314                 if (irq)                                                \
 315                         local_irq_save(__flags);                        \
 316                 __asm__ __volatile__(                                   \
 317                         ".set   mips3"          "\t\t# __writeq""\n\t"  \
 318                         "dsll32 %L0, %L0, 0"                    "\n\t"  \
 319                         "dsrl32 %L0, %L0, 0"                    "\n\t"  \
 320                         "dsll32 %M0, %M0, 0"                    "\n\t"  \
 321                         "or     %L0, %L0, %M0"                  "\n\t"  \
 322                         "sd     %L0, %2"                        "\n\t"  \
 323                         ".set   mips0"                          "\n"    \
 324                         : "=r" (__tmp)                                  \
 325                         : "0" (__val), "m" (*__mem));                   \
 326                 if (irq)                                                \
 327                         local_irq_restore(__flags);                     \
 328         } else                                                          \
 329                 BUG();                                                  \
 330 }                                                                       \
 331                                                                         \
 332 static inline type pfx##read##bwlq(const volatile void __iomem *mem)    \
 333 {                                                                       \
 334         volatile type *__mem;                                           \
 335         type __val;                                                     \
 336                                                                         \
 337         __mem = (void *)__swizzle_addr_##bwlq((unsigned long)(mem));    \
 338                                                                         \
 339         if (sizeof(type) != sizeof(u64) || sizeof(u64) == sizeof(long)) \
 340                 __val = *__mem;                                         \
 341         else if (cpu_has_64bits) {                                      \
 342                 unsigned long __flags;                                  \
 343                                                                         \
 344                 if (irq)                                                \
 345                         local_irq_save(__flags);                        \
 346                 __asm__ __volatile__(                                   \
 347                         ".set   mips3"          "\t\t# __readq" "\n\t"  \
 348                         "ld     %L0, %1"                        "\n\t"  \
 349                         "dsra32 %M0, %L0, 0"                    "\n\t"  \
 350                         "sll    %L0, %L0, 0"                    "\n\t"  \
 351                         ".set   mips0"                          "\n"    \
 352                         : "=r" (__val)                                  \
 353                         : "m" (*__mem));                                \
 354                 if (irq)                                                \
 355                         local_irq_restore(__flags);                     \
 356         } else {                                                        \
 357                 __val = 0;                                              \
 358                 BUG();                                                  \
 359         }                                                               \
 360                                                                         \
 361         return pfx##ioswab##bwlq(__mem, __val);                         \
 362 }
 363
 364 #define __BUILD_IOPORT_SINGLE(pfx, bwlq, type, p, slow)                 \
 365                                                                         \
 366 static inline void pfx##out##bwlq##p(type val, unsigned long port)      \
 367 {                                                                       \
 368         volatile type *__addr;                                          \
 369         type __val;                                                     \
 370                                                                         \
 371         __addr = (void *)__swizzle_addr_##bwlq(mips_io_port_base + port); \
 372                                                                         \
 373         __val = pfx##ioswab##bwlq(__addr, val);                         \
 374                                                                         \
 375         /* Really, we want this to be atomic */                         \
 376         BUILD_BUG_ON(sizeof(type) > sizeof(unsigned long));             \
 377                                                                         \
 378         *__addr = __val;                                                \
 379         slow;                                                           \
 380 }                                                                       \
 381                                                                         \
 382 static inline type pfx##in##bwlq##p(unsigned long port)                 \
 383 {                                                                       \
 384         volatile type *__addr;                                          \
 385         type __val;                                                     \
 386                                                                         \
 387         __addr = (void *)__swizzle_addr_##bwlq(mips_io_port_base + port); \
 388                                                                         \
 389         BUILD_BUG_ON(sizeof(type) > sizeof(unsigned long));             \
 390                                                                         \
 391         __val = *__addr;                                                \
 392         slow;                                                           \
 393                                                                         \
 394         return pfx##ioswab##bwlq(__addr, __val);                        \
 395 }
 396
 397 #define __BUILD_MEMORY_PFX(bus, bwlq, type)                             \
 398                                                                         \
 399 __BUILD_MEMORY_SINGLE(bus, bwlq, type, 1)
 400
 401 #define BUILDIO_MEM(bwlq, type)                                         \
 402                                                                         \
 403 __BUILD_MEMORY_PFX(__raw_, bwlq, type)                                  \
 404 __BUILD_MEMORY_PFX(, bwlq, type)                                        \
 405 __BUILD_MEMORY_PFX(__mem_, bwlq, type)                                  \
 406
 407 BUILDIO_MEM(b, u8)
 408 BUILDIO_MEM(w, u16)
 409 BUILDIO_MEM(l, u32)
 410 BUILDIO_MEM(q, u64)
 411
 412 #define __BUILD_IOPORT_PFX(bus, bwlq, type)                             \
 413         __BUILD_IOPORT_SINGLE(bus, bwlq, type, ,)                       \
 414         __BUILD_IOPORT_SINGLE(bus, bwlq, type, _p, SLOW_DOWN_IO)
 415
 416 #define BUILDIO_IOPORT(bwlq, type)                                      \
 417         __BUILD_IOPORT_PFX(, bwlq, type)                                \
 418         __BUILD_IOPORT_PFX(__mem_, bwlq, type)
 419
 420 BUILDIO_IOPORT(b, u8)
 421 BUILDIO_IOPORT(w, u16)
 422 BUILDIO_IOPORT(l, u32)
 423 #ifdef CONFIG_64BIT
 424 BUILDIO_IOPORT(q, u64)
 425 #endif
 426
 427 #define __BUILDIO(bwlq, type)                                           \
 428                                                                         \
 429 __BUILD_MEMORY_SINGLE(____raw_, bwlq, type, 0)
 430
 431 __BUILDIO(q, u64)
 432
 433 #define readb_relaxed                   readb
 434 #define readw_relaxed                   readw
 435 #define readl_relaxed                   readl
 436 #define readq_relaxed                   readq
 437
 438 /*
 439  * Some code tests for these symbols
 440  */
 441 #define readq                           readq
 442 #define writeq                          writeq
 443
 444 #define __BUILD_MEMORY_STRING(bwlq, type)                               \
 445                                                                         \
 446 static inline void writes##bwlq(volatile void __iomem *mem,             \
 447                                 const void *addr, unsigned int count)   \
 448 {                                                                       \
 449         const volatile type *__addr = addr;                             \
 450                                                                         \
 451         while (count--) {                                               \
 452                 __mem_write##bwlq(*__addr, mem);                        \
 453                 __addr++;                                               \
 454         }                                                               \
 455 }                                                                       \
 456                                                                         \
 457 static inline void reads##bwlq(volatile void __iomem *mem, void *addr,  \
 458                                unsigned int count)                      \
 459 {                                                                       \
 460         volatile type *__addr = addr;                                   \
 461                                                                         \
 462         while (count--) {                                               \
 463                 *__addr = __mem_read##bwlq(mem);                        \
 464                 __addr++;                                               \
 465         }                                                               \
 466 }
 467
 468 #define __BUILD_IOPORT_STRING(bwlq, type)                               \
 469                                                                         \
 470 static inline void outs##bwlq(unsigned long port, const void *addr,     \
 471                               unsigned int count)                       \
 472 {                                                                       \
 473         const volatile type *__addr = addr;                             \
 474                                                                         \
 475         while (count--) {                                               \
 476                 __mem_out##bwlq(*__addr, port);                         \
 477                 __addr++;                                               \
 478         }                                                               \
 479 }                                                                       \
 480                                                                         \
 481 static inline void ins##bwlq(unsigned long port, void *addr,            \
 482                              unsigned int count)                        \
 483 {                                                                       \
 484         volatile type *__addr = addr;                                   \
 485                                                                         \
 486         while (count--) {                                               \
 487                 *__addr = __mem_in##bwlq(port);                         \
 488                 __addr++;                                               \
 489         }                                                               \
 490 }
 491
 492 #define BUILDSTRING(bwlq, type)                                         \
 493                                                                         \
 494 __BUILD_MEMORY_STRING(bwlq, type)                                       \
 495 __BUILD_IOPORT_STRING(bwlq, type)
 496
 497 BUILDSTRING(b, u8)
 498 BUILDSTRING(w, u16)
 499 BUILDSTRING(l, u32)
 500 #ifdef CONFIG_64BIT
 501 BUILDSTRING(q, u64)
 502 #endif
 503
 504
 505 /* Depends on MIPS II instruction set */
 506 #define mmiowb() asm volatile ("sync" ::: "memory")
 507
 508 static inline void memset_io(volatile void __iomem *addr, unsigned char val, int count)
 509 {
 510         memset((void __force *) addr, val, count);
 511 }
 512 static inline void memcpy_fromio(void *dst, const volatile void __iomem *src, int count)
 513 {
 514         memcpy(dst, (void __force *) src, count);
 515 }
 516 static inline void memcpy_toio(volatile void __iomem *dst, const void *src, int count)
 517 {
 518         memcpy((void __force *) dst, src, count);
 519 }
 520
 521 /*
 522  * ISA space is 'always mapped' on currently supported MIPS systems, no need
 523  * to explicitly ioremap() it. The fact that the ISA IO space is mapped
 524  * to PAGE_OFFSET is pure coincidence - it does not mean ISA values
 525  * are physical addresses. The following constant pointer can be
 526  * used as the IO-area pointer (it can be iounmapped as well, so the
 527  * analogy with PCI is quite large):
 528  */
 529 #define __ISA_IO_base ((char *)(isa_slot_offset))
 530
 531 /*
 532  * The caches on some architectures aren't dma-coherent and have need to
 533  * handle this in software.  There are three types of operations that
 534  * can be applied to dma buffers.
 535  *
 536  *  - dma_cache_wback_inv(start, size) makes caches and coherent by
 537  *    writing the content of the caches back to memory, if necessary.
 538  *    The function also invalidates the affected part of the caches as
 539  *    necessary before DMA transfers from outside to memory.
 540  *  - dma_cache_wback(start, size) makes caches and coherent by
 541  *    writing the content of the caches back to memory, if necessary.
 542  *    The function also invalidates the affected part of the caches as
 543  *    necessary before DMA transfers from outside to memory.
 544  *  - dma_cache_inv(start, size) invalidates the affected parts of the
 545  *    caches.  Dirty lines of the caches may be written back or simply
 546  *    be discarded.  This operation is necessary before dma operations
 547  *    to the memory.
 548  */
 549 #ifdef CONFIG_DMA_NONCOHERENT
 550
 551 extern void (*_dma_cache_wback_inv)(unsigned long start, unsigned long size);
 552 extern void (*_dma_cache_wback)(unsigned long start, unsigned long size);
 553 extern void (*_dma_cache_inv)(unsigned long start, unsigned long size);
 554
 555 #define dma_cache_wback_inv(start, size)        _dma_cache_wback_inv(start,size)
 556 #define dma_cache_wback(start, size)            _dma_cache_wback(start,size)
 557 #define dma_cache_inv(start, size)              _dma_cache_inv(start,size)
 558
 559 #else /* Sane hardware */
 560
 561 #define dma_cache_wback_inv(start,size) \
 562         do { (void) (start); (void) (size); } while (0)
 563 #define dma_cache_wback(start,size)     \
 564         do { (void) (start); (void) (size); } while (0)
 565 #define dma_cache_inv(start,size)       \
 566         do { (void) (start); (void) (size); } while (0)
 567
 568 #endif /* CONFIG_DMA_NONCOHERENT */
 569
 570 /*
 571  * Read a 32-bit register that requires a 64-bit read cycle on the bus.
 572  * Avoid interrupt mucking, just adjust the address for 4-byte access.
 573  * Assume the addresses are 8-byte aligned.
 574  */
 575 #ifdef __MIPSEB__
 576 #define __CSR_32_ADJUST 4
 577 #else
 578 #define __CSR_32_ADJUST 0
 579 #endif
 580
 581 #define csr_out32(v,a) (*(volatile u32 *)((unsigned long)(a) + __CSR_32_ADJUST) = (v))
 582 #define csr_in32(a)    (*(volatile u32 *)((unsigned long)(a) + __CSR_32_ADJUST))
 583
 584 /*
 585  * Convert a physical pointer to a virtual kernel pointer for /dev/mem
 586  * access
 587  */
 588 #define xlate_dev_mem_ptr(p)    __va(p)
 589
 590 /*
 591  * Convert a virtual cached pointer to an uncached pointer
 592  */
 593 #define xlate_dev_kmem_ptr(p)   p
 594
 595 #endif /* _ASM_IO_H */