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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 #include <linux/irqflags.h>
19 
20 #include <asm/addrspace.h>
21 #include <asm/bug.h>
22 #include <asm/byteorder.h>
23 #include <asm/cpu.h>
24 #include <asm/cpu-features.h>
25 #include <asm-generic/iomap.h>
26 #include <asm/page.h>
27 #include <asm/pgtable-bits.h>
28 #include <asm/processor.h>
29 #include <asm/string.h>
30 
31 #include <ioremap.h>
32 #include <mangle-port.h>
33 
34 /*
35  * Slowdown I/O port space accesses for antique hardware.
36  */
37 #undef CONF_SLOWDOWN_IO
38 
39 /*
40  * Raw operations are never swapped in software.  OTOH values that raw
41  * operations are working on may or may not have been swapped by the bus
42  * hardware.  An example use would be for flash memory that's used for
43  * execute in place.
44  */
45 # define __raw_ioswabb(a, x)	(x)
46 # define __raw_ioswabw(a, x)	(x)
47 # define __raw_ioswabl(a, x)	(x)
48 # define __raw_ioswabq(a, x)	(x)
49 # define ____raw_ioswabq(a, x)	(x)
50 
51 /* ioswab[bwlq], __mem_ioswab[bwlq] are defined in mangle-port.h */
52 
53 #define IO_SPACE_LIMIT 0xffff
54 
55 /*
56  * On MIPS I/O ports are memory mapped, so we access them using normal
57  * load/store instructions. mips_io_port_base is the virtual address to
58  * which all ports are being mapped.  For sake of efficiency some code
59  * assumes that this is an address that can be loaded with a single lui
60  * instruction, so the lower 16 bits must be zero.  Should be true on
61  * on any sane architecture; generic code does not use this assumption.
62  */
63 extern unsigned long mips_io_port_base;
64 
set_io_port_base(unsigned long base)65 static inline void set_io_port_base(unsigned long base)
66 {
67 	mips_io_port_base = base;
68 }
69 
70 /*
71  * Thanks to James van Artsdalen for a better timing-fix than
72  * the two short jumps: using outb's to a nonexistent port seems
73  * to guarantee better timings even on fast machines.
74  *
75  * On the other hand, I'd like to be sure of a non-existent port:
76  * I feel a bit unsafe about using 0x80 (should be safe, though)
77  *
78  *		Linus
79  *
80  */
81 
82 #define __SLOW_DOWN_IO \
83 	__asm__ __volatile__( \
84 		"sb\t$0,0x80(%0)" \
85 		: : "r" (mips_io_port_base));
86 
87 #ifdef CONF_SLOWDOWN_IO
88 #ifdef REALLY_SLOW_IO
89 #define SLOW_DOWN_IO { __SLOW_DOWN_IO; __SLOW_DOWN_IO; __SLOW_DOWN_IO; __SLOW_DOWN_IO; }
90 #else
91 #define SLOW_DOWN_IO __SLOW_DOWN_IO
92 #endif
93 #else
94 #define SLOW_DOWN_IO
95 #endif
96 
97 /*
98  *     virt_to_phys    -       map virtual addresses to physical
99  *     @address: address to remap
100  *
101  *     The returned physical address is the physical (CPU) mapping for
102  *     the memory address given. It is only valid to use this function on
103  *     addresses directly mapped or allocated via kmalloc.
104  *
105  *     This function does not give bus mappings for DMA transfers. In
106  *     almost all conceivable cases a device driver should not be using
107  *     this function
108  */
virt_to_phys(volatile const void * address)109 static inline unsigned long virt_to_phys(volatile const void *address)
110 {
111 	return __pa(address);
112 }
113 
114 /*
115  *     phys_to_virt    -       map physical address to virtual
116  *     @address: address to remap
117  *
118  *     The returned virtual address is a current CPU mapping for
119  *     the memory address given. It is only valid to use this function on
120  *     addresses that have a kernel mapping
121  *
122  *     This function does not handle bus mappings for DMA transfers. In
123  *     almost all conceivable cases a device driver should not be using
124  *     this function
125  */
phys_to_virt(unsigned long address)126 static inline void * phys_to_virt(unsigned long address)
127 {
128 	return (void *)(address + PAGE_OFFSET - PHYS_OFFSET);
129 }
130 
131 /*
132  * ISA I/O bus memory addresses are 1:1 with the physical address.
133  */
isa_virt_to_bus(volatile void * address)134 static inline unsigned long isa_virt_to_bus(volatile void *address)
135 {
136 	return virt_to_phys(address);
137 }
138 
isa_bus_to_virt(unsigned long address)139 static inline void *isa_bus_to_virt(unsigned long address)
140 {
141 	return phys_to_virt(address);
142 }
143 
144 #define isa_page_to_bus page_to_phys
145 
146 /*
147  * However PCI ones are not necessarily 1:1 and therefore these interfaces
148  * are forbidden in portable PCI drivers.
149  *
150  * Allow them for x86 for legacy drivers, though.
151  */
152 #define virt_to_bus virt_to_phys
153 #define bus_to_virt phys_to_virt
154 
155 /*
156  * Change "struct page" to physical address.
157  */
158 #define page_to_phys(page)	((dma_addr_t)page_to_pfn(page) << PAGE_SHIFT)
159 
160 extern void __iomem * __ioremap(phys_addr_t offset, phys_addr_t size, unsigned long flags);
161 extern void __iounmap(const volatile void __iomem *addr);
162 
163 #ifndef CONFIG_PCI
164 struct pci_dev;
pci_iounmap(struct pci_dev * dev,void __iomem * addr)165 static inline void pci_iounmap(struct pci_dev *dev, void __iomem *addr) {}
166 #endif
167 
__ioremap_mode(phys_addr_t offset,unsigned long size,unsigned long flags)168 static inline void __iomem * __ioremap_mode(phys_addr_t offset, unsigned long size,
169 	unsigned long flags)
170 {
171 	void __iomem *addr = plat_ioremap(offset, size, flags);
172 
173 	if (addr)
174 		return addr;
175 
176 #define __IS_LOW512(addr) (!((phys_addr_t)(addr) & (phys_addr_t) ~0x1fffffffULL))
177 
178 	if (cpu_has_64bit_addresses) {
179 		u64 base = UNCAC_BASE;
180 
181 		/*
182 		 * R10000 supports a 2 bit uncached attribute therefore
183 		 * UNCAC_BASE may not equal IO_BASE.
184 		 */
185 		if (flags == _CACHE_UNCACHED)
186 			base = (u64) IO_BASE;
187 		return (void __iomem *) (unsigned long) (base + offset);
188 	} else if (__builtin_constant_p(offset) &&
189 		   __builtin_constant_p(size) && __builtin_constant_p(flags)) {
190 		phys_addr_t phys_addr, last_addr;
191 
192 		phys_addr = fixup_bigphys_addr(offset, size);
193 
194 		/* Don't allow wraparound or zero size. */
195 		last_addr = phys_addr + size - 1;
196 		if (!size || last_addr < phys_addr)
197 			return NULL;
198 
199 		/*
200 		 * Map uncached objects in the low 512MB of address
201 		 * space using KSEG1.
202 		 */
203 		if (__IS_LOW512(phys_addr) && __IS_LOW512(last_addr) &&
204 		    flags == _CACHE_UNCACHED)
205 			return (void __iomem *)
206 				(unsigned long)CKSEG1ADDR(phys_addr);
207 	}
208 
209 	return __ioremap(offset, size, flags);
210 
211 #undef __IS_LOW512
212 }
213 
214 /*
215  * ioremap     -   map bus memory into CPU space
216  * @offset:    bus address of the memory
217  * @size:      size of the resource to map
218  *
219  * ioremap performs a platform specific sequence of operations to
220  * make bus memory CPU accessible via the readb/readw/readl/writeb/
221  * writew/writel functions and the other mmio helpers. The returned
222  * address is not guaranteed to be usable directly as a virtual
223  * address.
224  */
225 #define ioremap(offset, size)						\
226 	__ioremap_mode((offset), (size), _CACHE_UNCACHED)
227 
228 /*
229  * ioremap_nocache     -   map bus memory into CPU space
230  * @offset:    bus address of the memory
231  * @size:      size of the resource to map
232  *
233  * ioremap_nocache performs a platform specific sequence of operations to
234  * make bus memory CPU accessible via the readb/readw/readl/writeb/
235  * writew/writel functions and the other mmio helpers. The returned
236  * address is not guaranteed to be usable directly as a virtual
237  * address.
238  *
239  * This version of ioremap ensures that the memory is marked uncachable
240  * on the CPU as well as honouring existing caching rules from things like
241  * the PCI bus. Note that there are other caches and buffers on many
242  * busses. In particular driver authors should read up on PCI writes
243  *
244  * It's useful if some control registers are in such an area and
245  * write combining or read caching is not desirable:
246  */
247 #define ioremap_nocache(offset, size)					\
248 	__ioremap_mode((offset), (size), _CACHE_UNCACHED)
249 #define ioremap_uc ioremap_nocache
250 
251 /*
252  * ioremap_cachable -	map bus memory into CPU space
253  * @offset:	    bus address of the memory
254  * @size:	    size of the resource to map
255  *
256  * ioremap_nocache performs a platform specific sequence of operations to
257  * make bus memory CPU accessible via the readb/readw/readl/writeb/
258  * writew/writel functions and the other mmio helpers. The returned
259  * address is not guaranteed to be usable directly as a virtual
260  * address.
261  *
262  * This version of ioremap ensures that the memory is marked cachable by
263  * the CPU.  Also enables full write-combining.	 Useful for some
264  * memory-like regions on I/O busses.
265  */
266 #define ioremap_cachable(offset, size)					\
267 	__ioremap_mode((offset), (size), _page_cachable_default)
268 
269 /*
270  * These two are MIPS specific ioremap variant.	 ioremap_cacheable_cow
271  * requests a cachable mapping, ioremap_uncached_accelerated requests a
272  * mapping using the uncached accelerated mode which isn't supported on
273  * all processors.
274  */
275 #define ioremap_cacheable_cow(offset, size)				\
276 	__ioremap_mode((offset), (size), _CACHE_CACHABLE_COW)
277 #define ioremap_uncached_accelerated(offset, size)			\
278 	__ioremap_mode((offset), (size), _CACHE_UNCACHED_ACCELERATED)
279 
iounmap(const volatile void __iomem * addr)280 static inline void iounmap(const volatile void __iomem *addr)
281 {
282 	if (plat_iounmap(addr))
283 		return;
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 #ifdef CONFIG_CPU_CAVIUM_OCTEON
297 #define war_octeon_io_reorder_wmb()		wmb()
298 #else
299 #define war_octeon_io_reorder_wmb()		do { } while (0)
300 #endif
301 
302 #define __BUILD_MEMORY_SINGLE(pfx, bwlq, type, irq)			\
303 									\
304 static inline void pfx##write##bwlq(type val,				\
305 				    volatile void __iomem *mem)		\
306 {									\
307 	volatile type *__mem;						\
308 	type __val;							\
309 									\
310 	war_octeon_io_reorder_wmb();					\
311 									\
312 	__mem = (void *)__swizzle_addr_##bwlq((unsigned long)(mem));	\
313 									\
314 	__val = pfx##ioswab##bwlq(__mem, val);				\
315 									\
316 	if (sizeof(type) != sizeof(u64) || sizeof(u64) == sizeof(long)) \
317 		*__mem = __val;						\
318 	else if (cpu_has_64bits) {					\
319 		unsigned long __flags;					\
320 		type __tmp;						\
321 									\
322 		if (irq)						\
323 			local_irq_save(__flags);			\
324 		__asm__ __volatile__(					\
325 			".set	arch=r4000"	"\t\t# __writeq""\n\t"	\
326 			"dsll32 %L0, %L0, 0"			"\n\t"	\
327 			"dsrl32 %L0, %L0, 0"			"\n\t"	\
328 			"dsll32 %M0, %M0, 0"			"\n\t"	\
329 			"or	%L0, %L0, %M0"			"\n\t"	\
330 			"sd	%L0, %2"			"\n\t"	\
331 			".set	mips0"				"\n"	\
332 			: "=r" (__tmp)					\
333 			: "0" (__val), "m" (*__mem));			\
334 		if (irq)						\
335 			local_irq_restore(__flags);			\
336 	} else								\
337 		BUG();							\
338 }									\
339 									\
340 static inline type pfx##read##bwlq(const volatile void __iomem *mem)	\
341 {									\
342 	volatile type *__mem;						\
343 	type __val;							\
344 									\
345 	__mem = (void *)__swizzle_addr_##bwlq((unsigned long)(mem));	\
346 									\
347 	if (sizeof(type) != sizeof(u64) || sizeof(u64) == sizeof(long)) \
348 		__val = *__mem;						\
349 	else if (cpu_has_64bits) {					\
350 		unsigned long __flags;					\
351 									\
352 		if (irq)						\
353 			local_irq_save(__flags);			\
354 		__asm__ __volatile__(					\
355 			".set	arch=r4000"	"\t\t# __readq" "\n\t"	\
356 			"ld	%L0, %1"			"\n\t"	\
357 			"dsra32 %M0, %L0, 0"			"\n\t"	\
358 			"sll	%L0, %L0, 0"			"\n\t"	\
359 			".set	mips0"				"\n"	\
360 			: "=r" (__val)					\
361 			: "m" (*__mem));				\
362 		if (irq)						\
363 			local_irq_restore(__flags);			\
364 	} else {							\
365 		__val = 0;						\
366 		BUG();							\
367 	}								\
368 									\
369 	return pfx##ioswab##bwlq(__mem, __val);				\
370 }
371 
372 #define __BUILD_IOPORT_SINGLE(pfx, bwlq, type, p, slow)			\
373 									\
374 static inline void pfx##out##bwlq##p(type val, unsigned long port)	\
375 {									\
376 	volatile type *__addr;						\
377 	type __val;							\
378 									\
379 	war_octeon_io_reorder_wmb();					\
380 									\
381 	__addr = (void *)__swizzle_addr_##bwlq(mips_io_port_base + port); \
382 									\
383 	__val = pfx##ioswab##bwlq(__addr, val);				\
384 									\
385 	/* Really, we want this to be atomic */				\
386 	BUILD_BUG_ON(sizeof(type) > sizeof(unsigned long));		\
387 									\
388 	*__addr = __val;						\
389 	slow;								\
390 }									\
391 									\
392 static inline type pfx##in##bwlq##p(unsigned long port)			\
393 {									\
394 	volatile type *__addr;						\
395 	type __val;							\
396 									\
397 	__addr = (void *)__swizzle_addr_##bwlq(mips_io_port_base + port); \
398 									\
399 	BUILD_BUG_ON(sizeof(type) > sizeof(unsigned long));		\
400 									\
401 	__val = *__addr;						\
402 	slow;								\
403 									\
404 	/* prevent prefetching of coherent DMA data prematurely */	\
405 	rmb();								\
406 	return pfx##ioswab##bwlq(__addr, __val);			\
407 }
408 
409 #define __BUILD_MEMORY_PFX(bus, bwlq, type)				\
410 									\
411 __BUILD_MEMORY_SINGLE(bus, bwlq, type, 1)
412 
413 #define BUILDIO_MEM(bwlq, type)						\
414 									\
415 __BUILD_MEMORY_PFX(__raw_, bwlq, type)					\
416 __BUILD_MEMORY_PFX(, bwlq, type)					\
417 __BUILD_MEMORY_PFX(__mem_, bwlq, type)					\
418 
BUILDIO_MEM(b,u8)419 BUILDIO_MEM(b, u8)
420 BUILDIO_MEM(w, u16)
421 BUILDIO_MEM(l, u32)
422 BUILDIO_MEM(q, u64)
423 
424 #define __BUILD_IOPORT_PFX(bus, bwlq, type)				\
425 	__BUILD_IOPORT_SINGLE(bus, bwlq, type, ,)			\
426 	__BUILD_IOPORT_SINGLE(bus, bwlq, type, _p, SLOW_DOWN_IO)
427 
428 #define BUILDIO_IOPORT(bwlq, type)					\
429 	__BUILD_IOPORT_PFX(, bwlq, type)				\
430 	__BUILD_IOPORT_PFX(__mem_, bwlq, type)
431 
432 BUILDIO_IOPORT(b, u8)
433 BUILDIO_IOPORT(w, u16)
434 BUILDIO_IOPORT(l, u32)
435 #ifdef CONFIG_64BIT
436 BUILDIO_IOPORT(q, u64)
437 #endif
438 
439 #define __BUILDIO(bwlq, type)						\
440 									\
441 __BUILD_MEMORY_SINGLE(____raw_, bwlq, type, 0)
442 
443 __BUILDIO(q, u64)
444 
445 #define readb_relaxed			readb
446 #define readw_relaxed			readw
447 #define readl_relaxed			readl
448 #define readq_relaxed			readq
449 
450 #define writeb_relaxed			writeb
451 #define writew_relaxed			writew
452 #define writel_relaxed			writel
453 #define writeq_relaxed			writeq
454 
455 #define readb_be(addr)							\
456 	__raw_readb((__force unsigned *)(addr))
457 #define readw_be(addr)							\
458 	be16_to_cpu(__raw_readw((__force unsigned *)(addr)))
459 #define readl_be(addr)							\
460 	be32_to_cpu(__raw_readl((__force unsigned *)(addr)))
461 #define readq_be(addr)							\
462 	be64_to_cpu(__raw_readq((__force unsigned *)(addr)))
463 
464 #define writeb_be(val, addr)						\
465 	__raw_writeb((val), (__force unsigned *)(addr))
466 #define writew_be(val, addr)						\
467 	__raw_writew(cpu_to_be16((val)), (__force unsigned *)(addr))
468 #define writel_be(val, addr)						\
469 	__raw_writel(cpu_to_be32((val)), (__force unsigned *)(addr))
470 #define writeq_be(val, addr)						\
471 	__raw_writeq(cpu_to_be64((val)), (__force unsigned *)(addr))
472 
473 /*
474  * Some code tests for these symbols
475  */
476 #define readq				readq
477 #define writeq				writeq
478 
479 #define __BUILD_MEMORY_STRING(bwlq, type)				\
480 									\
481 static inline void writes##bwlq(volatile void __iomem *mem,		\
482 				const void *addr, unsigned int count)	\
483 {									\
484 	const volatile type *__addr = addr;				\
485 									\
486 	while (count--) {						\
487 		__mem_write##bwlq(*__addr, mem);			\
488 		__addr++;						\
489 	}								\
490 }									\
491 									\
492 static inline void reads##bwlq(volatile void __iomem *mem, void *addr,	\
493 			       unsigned int count)			\
494 {									\
495 	volatile type *__addr = addr;					\
496 									\
497 	while (count--) {						\
498 		*__addr = __mem_read##bwlq(mem);			\
499 		__addr++;						\
500 	}								\
501 }
502 
503 #define __BUILD_IOPORT_STRING(bwlq, type)				\
504 									\
505 static inline void outs##bwlq(unsigned long port, const void *addr,	\
506 			      unsigned int count)			\
507 {									\
508 	const volatile type *__addr = addr;				\
509 									\
510 	while (count--) {						\
511 		__mem_out##bwlq(*__addr, port);				\
512 		__addr++;						\
513 	}								\
514 }									\
515 									\
516 static inline void ins##bwlq(unsigned long port, void *addr,		\
517 			     unsigned int count)			\
518 {									\
519 	volatile type *__addr = addr;					\
520 									\
521 	while (count--) {						\
522 		*__addr = __mem_in##bwlq(port);				\
523 		__addr++;						\
524 	}								\
525 }
526 
527 #define BUILDSTRING(bwlq, type)						\
528 									\
529 __BUILD_MEMORY_STRING(bwlq, type)					\
530 __BUILD_IOPORT_STRING(bwlq, type)
531 
532 BUILDSTRING(b, u8)
533 BUILDSTRING(w, u16)
534 BUILDSTRING(l, u32)
535 #ifdef CONFIG_64BIT
536 BUILDSTRING(q, u64)
537 #endif
538 
539 
540 #ifdef CONFIG_CPU_CAVIUM_OCTEON
541 #define mmiowb() wmb()
542 #else
543 /* Depends on MIPS II instruction set */
544 #define mmiowb() asm volatile ("sync" ::: "memory")
545 #endif
546 
547 static inline void memset_io(volatile void __iomem *addr, unsigned char val, int count)
548 {
549 	memset((void __force *) addr, val, count);
550 }
memcpy_fromio(void * dst,const volatile void __iomem * src,int count)551 static inline void memcpy_fromio(void *dst, const volatile void __iomem *src, int count)
552 {
553 	memcpy(dst, (void __force *) src, count);
554 }
memcpy_toio(volatile void __iomem * dst,const void * src,int count)555 static inline void memcpy_toio(volatile void __iomem *dst, const void *src, int count)
556 {
557 	memcpy((void __force *) dst, src, count);
558 }
559 
560 /*
561  * The caches on some architectures aren't dma-coherent and have need to
562  * handle this in software.  There are three types of operations that
563  * can be applied to dma buffers.
564  *
565  *  - dma_cache_wback_inv(start, size) makes caches and coherent by
566  *    writing the content of the caches back to memory, if necessary.
567  *    The function also invalidates the affected part of the caches as
568  *    necessary before DMA transfers from outside to memory.
569  *  - dma_cache_wback(start, size) makes caches and coherent by
570  *    writing the content of the caches back to memory, if necessary.
571  *    The function also invalidates the affected part of the caches as
572  *    necessary before DMA transfers from outside to memory.
573  *  - dma_cache_inv(start, size) invalidates the affected parts of the
574  *    caches.  Dirty lines of the caches may be written back or simply
575  *    be discarded.  This operation is necessary before dma operations
576  *    to the memory.
577  *
578  * This API used to be exported; it now is for arch code internal use only.
579  */
580 #if defined(CONFIG_DMA_NONCOHERENT) || defined(CONFIG_DMA_MAYBE_COHERENT)
581 
582 extern void (*_dma_cache_wback_inv)(unsigned long start, unsigned long size);
583 extern void (*_dma_cache_wback)(unsigned long start, unsigned long size);
584 extern void (*_dma_cache_inv)(unsigned long start, unsigned long size);
585 
586 #define dma_cache_wback_inv(start, size)	_dma_cache_wback_inv(start, size)
587 #define dma_cache_wback(start, size)		_dma_cache_wback(start, size)
588 #define dma_cache_inv(start, size)		_dma_cache_inv(start, size)
589 
590 #else /* Sane hardware */
591 
592 #define dma_cache_wback_inv(start,size) \
593 	do { (void) (start); (void) (size); } while (0)
594 #define dma_cache_wback(start,size)	\
595 	do { (void) (start); (void) (size); } while (0)
596 #define dma_cache_inv(start,size)	\
597 	do { (void) (start); (void) (size); } while (0)
598 
599 #endif /* CONFIG_DMA_NONCOHERENT || CONFIG_DMA_MAYBE_COHERENT */
600 
601 /*
602  * Read a 32-bit register that requires a 64-bit read cycle on the bus.
603  * Avoid interrupt mucking, just adjust the address for 4-byte access.
604  * Assume the addresses are 8-byte aligned.
605  */
606 #ifdef __MIPSEB__
607 #define __CSR_32_ADJUST 4
608 #else
609 #define __CSR_32_ADJUST 0
610 #endif
611 
612 #define csr_out32(v, a) (*(volatile u32 *)((unsigned long)(a) + __CSR_32_ADJUST) = (v))
613 #define csr_in32(a)    (*(volatile u32 *)((unsigned long)(a) + __CSR_32_ADJUST))
614 
615 /*
616  * Convert a physical pointer to a virtual kernel pointer for /dev/mem
617  * access
618  */
619 #define xlate_dev_mem_ptr(p)	__va(p)
620 
621 /*
622  * Convert a virtual cached pointer to an uncached pointer
623  */
624 #define xlate_dev_kmem_ptr(p)	p
625 
626 #endif /* _ASM_IO_H */
627