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authorRalf Baechle <ralf@linux-mips.org>2007-10-16 23:29:42 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-17 08:42:57 -0700
commit622a9edd919de98ef59571ae6c40c7458244e3f2 (patch)
treec25684f90ed52c459c39d97d6ab641fe3bb6b09d
parentbc154b1efb7f8430ea9faabd5953ebc411f8ead5 (diff)
Remove dma_cache_(wback|inv|wback_inv) functions
dma_cache_(wback|inv|wback_inv) were the earliest attempt on a generalized cache managment API for I/O purposes. Originally it was basically the raw MIPS low level cache API exported to the entire world. The API has suffered from a lack of documentation, was not very widely used unlike it's more modern brothers and can easily be replaced by dma_cache_sync. So remove it rsp. turn the surviving bits back into an arch private API, as discussed on linux-arch. Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Acked-by: Paul Mundt <lethal@linux-sh.org> Acked-by: Paul Mackerras <paulus@samba.org> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Kyle McMartin <kyle@parisc-linux.org> Acked-by: Haavard Skinnemoen <hskinnemoen@atmel.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--arch/avr32/mm/dma-coherent.c6
-rw-r--r--arch/mips/mm/cache.c2
-rw-r--r--arch/sh/drivers/pci/dma-dreamcast.c2
-rw-r--r--arch/sh/mm/consistent.c8
-rw-r--r--arch/sh64/mm/consistent.c3
-rw-r--r--include/asm-alpha/io.h6
-rw-r--r--include/asm-avr32/io.h7
-rw-r--r--include/asm-blackfin/io.h4
-rw-r--r--include/asm-h8300/io.h6
-rw-r--r--include/asm-ia64/io.h4
-rw-r--r--include/asm-m68k/io.h6
-rw-r--r--include/asm-m68knommu/io.h6
-rw-r--r--include/asm-mips/io.h2
-rw-r--r--include/asm-parisc/io.h5
-rw-r--r--include/asm-powerpc/io.h17
-rw-r--r--include/asm-ppc/io.h17
-rw-r--r--include/asm-sh/floppy.h2
-rw-r--r--include/asm-sh/io.h25
-rw-r--r--include/asm-sh64/dma-mapping.h6
-rw-r--r--include/asm-sh64/io.h48
-rw-r--r--include/asm-sparc/io.h7
-rw-r--r--include/asm-sparc64/io.h6
-rw-r--r--include/asm-x86/io_32.h11
-rw-r--r--include/asm-x86/io_64.h6
24 files changed, 19 insertions, 193 deletions
diff --git a/arch/avr32/mm/dma-coherent.c b/arch/avr32/mm/dma-coherent.c
index 099212d4567..177fea8f7b7 100644
--- a/arch/avr32/mm/dma-coherent.c
+++ b/arch/avr32/mm/dma-coherent.c
@@ -21,13 +21,13 @@ void dma_cache_sync(struct device *dev, void *vaddr, size_t size, int direction)
switch (direction) {
case DMA_FROM_DEVICE: /* invalidate only */
- dma_cache_inv(vaddr, size);
+ invalidate_dcache_region(vaddr, size);
break;
case DMA_TO_DEVICE: /* writeback only */
- dma_cache_wback(vaddr, size);
+ clean_dcache_region(vaddr, size);
break;
case DMA_BIDIRECTIONAL: /* writeback and invalidate */
- dma_cache_wback_inv(vaddr, size);
+ flush_dcache_region(vaddr, size);
break;
default:
BUG();
diff --git a/arch/mips/mm/cache.c b/arch/mips/mm/cache.c
index 43dde874f41..81f30ac2bff 100644
--- a/arch/mips/mm/cache.c
+++ b/arch/mips/mm/cache.c
@@ -47,8 +47,6 @@ void (*_dma_cache_wback)(unsigned long start, unsigned long size);
void (*_dma_cache_inv)(unsigned long start, unsigned long size);
EXPORT_SYMBOL(_dma_cache_wback_inv);
-EXPORT_SYMBOL(_dma_cache_wback);
-EXPORT_SYMBOL(_dma_cache_inv);
#endif /* CONFIG_DMA_NONCOHERENT */
diff --git a/arch/sh/drivers/pci/dma-dreamcast.c b/arch/sh/drivers/pci/dma-dreamcast.c
index 230d6ec0d23..888a3405059 100644
--- a/arch/sh/drivers/pci/dma-dreamcast.c
+++ b/arch/sh/drivers/pci/dma-dreamcast.c
@@ -51,7 +51,7 @@ void *dreamcast_consistent_alloc(struct device *dev, size_t size,
buf = P2SEGADDR(buf);
/* Flush the dcache before we hand off the buffer */
- dma_cache_wback_inv((void *)buf, size);
+ __flush_purge_region((void *)buf, size);
return (void *)buf;
}
diff --git a/arch/sh/mm/consistent.c b/arch/sh/mm/consistent.c
index 38c82d890ff..e220c29a3c0 100644
--- a/arch/sh/mm/consistent.c
+++ b/arch/sh/mm/consistent.c
@@ -34,7 +34,7 @@ void *consistent_alloc(gfp_t gfp, size_t size, dma_addr_t *handle)
/*
* We must flush the cache before we pass it on to the device
*/
- dma_cache_wback_inv(ret, size);
+ __flush_purge_region(ret, size);
page = virt_to_page(ret);
free = page + (size >> PAGE_SHIFT);
@@ -68,13 +68,13 @@ void consistent_sync(void *vaddr, size_t size, int direction)
switch (direction) {
case DMA_FROM_DEVICE: /* invalidate only */
- dma_cache_inv(p1addr, size);
+ __flush_invalidate_region(p1addr, size);
break;
case DMA_TO_DEVICE: /* writeback only */
- dma_cache_wback(p1addr, size);
+ __flush_wback_region(p1addr, size);
break;
case DMA_BIDIRECTIONAL: /* writeback and invalidate */
- dma_cache_wback_inv(p1addr, size);
+ __flush_purge_region(p1addr, size);
break;
default:
BUG();
diff --git a/arch/sh64/mm/consistent.c b/arch/sh64/mm/consistent.c
index 8875a2a40da..c439620402c 100644
--- a/arch/sh64/mm/consistent.c
+++ b/arch/sh64/mm/consistent.c
@@ -11,6 +11,7 @@
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/pci.h>
+#include <linux/dma-mapping.h>
#include <linux/module.h>
#include <asm/io.h>
@@ -32,7 +33,7 @@ void *consistent_alloc(struct pci_dev *hwdev, size_t size,
if (vp != NULL) {
memset(vp, 0, size);
*dma_handle = virt_to_phys(ret);
- dma_cache_wback_inv((unsigned long)ret, size);
+ dma_cache_sync(NULL, ret, size, DMA_BIDIRECTIONAL);
}
return vp;
diff --git a/include/asm-alpha/io.h b/include/asm-alpha/io.h
index ab5b60dcef1..38f18cf18c9 100644
--- a/include/asm-alpha/io.h
+++ b/include/asm-alpha/io.h
@@ -551,12 +551,6 @@ extern void outsl (unsigned long port, const void *src, unsigned long count);
#endif
#define RTC_ALWAYS_BCD 0
-/* Nothing to do */
-
-#define dma_cache_inv(_start,_size) do { } while (0)
-#define dma_cache_wback(_start,_size) do { } while (0)
-#define dma_cache_wback_inv(_start,_size) do { } while (0)
-
/*
* Some mucking forons use if[n]def writeq to check if platform has it.
* It's a bloody bad idea and we probably want ARCH_HAS_WRITEQ for them
diff --git a/include/asm-avr32/io.h b/include/asm-avr32/io.h
index 64bb92bb677..8be7ea9c904 100644
--- a/include/asm-avr32/io.h
+++ b/include/asm-avr32/io.h
@@ -298,13 +298,6 @@ extern void __iounmap(void __iomem *addr);
#define ioport_map(port, nr) ioremap(port, nr)
#define ioport_unmap(port) iounmap(port)
-#define dma_cache_wback_inv(_start, _size) \
- flush_dcache_region(_start, _size)
-#define dma_cache_inv(_start, _size) \
- invalidate_dcache_region(_start, _size)
-#define dma_cache_wback(_start, _size) \
- clean_dcache_region(_start, _size)
-
/*
* Convert a physical pointer to a virtual kernel pointer for /dev/mem
* access
diff --git a/include/asm-blackfin/io.h b/include/asm-blackfin/io.h
index 525179bf43d..d1d2e6be3b5 100644
--- a/include/asm-blackfin/io.h
+++ b/include/asm-blackfin/io.h
@@ -183,10 +183,6 @@ extern void blkfin_inv_cache_all(void);
#define ioport_map(port, nr) ((void __iomem*)(port))
#define ioport_unmap(addr)
-#define dma_cache_inv(_start,_size) do { blkfin_inv_cache_all();} while (0)
-#define dma_cache_wback(_start,_size) do { } while (0)
-#define dma_cache_wback_inv(_start,_size) do { blkfin_inv_cache_all();} while (0)
-
/* Pages to physical address... */
#define page_to_phys(page) ((page - mem_map) << PAGE_SHIFT)
#define page_to_bus(page) ((page - mem_map) << PAGE_SHIFT)
diff --git a/include/asm-h8300/io.h b/include/asm-h8300/io.h
index 91b7487cb7a..7543a57b4ea 100644
--- a/include/asm-h8300/io.h
+++ b/include/asm-h8300/io.h
@@ -264,12 +264,6 @@ static inline void *ioremap_fullcache(unsigned long physaddr, unsigned long size
extern void iounmap(void *addr);
-/* Nothing to do */
-
-#define dma_cache_inv(_start,_size) do { } while (0)
-#define dma_cache_wback(_start,_size) do { } while (0)
-#define dma_cache_wback_inv(_start,_size) do { } while (0)
-
/* H8/300 internal I/O functions */
static __inline__ unsigned char ctrl_inb(unsigned long addr)
{
diff --git a/include/asm-ia64/io.h b/include/asm-ia64/io.h
index eb17a869296..4ebed77aa47 100644
--- a/include/asm-ia64/io.h
+++ b/include/asm-ia64/io.h
@@ -435,10 +435,6 @@ extern void memcpy_fromio(void *dst, const volatile void __iomem *src, long n);
extern void memcpy_toio(volatile void __iomem *dst, const void *src, long n);
extern void memset_io(volatile void __iomem *s, int c, long n);
-#define dma_cache_inv(_start,_size) do { } while (0)
-#define dma_cache_wback(_start,_size) do { } while (0)
-#define dma_cache_wback_inv(_start,_size) do { } while (0)
-
# endif /* __KERNEL__ */
/*
diff --git a/include/asm-m68k/io.h b/include/asm-m68k/io.h
index 47bb9cf107b..baf4f9b8acf 100644
--- a/include/asm-m68k/io.h
+++ b/include/asm-m68k/io.h
@@ -384,12 +384,6 @@ static inline void __iomem *ioremap_fullcache(unsigned long physaddr,
return __ioremap(physaddr, size, IOMAP_FULL_CACHING);
}
-
-/* m68k caches aren't DMA coherent */
-extern void dma_cache_wback_inv(unsigned long start, unsigned long size);
-extern void dma_cache_wback(unsigned long start, unsigned long size);
-extern void dma_cache_inv(unsigned long start, unsigned long size);
-
static inline void memset_io(volatile void __iomem *addr, unsigned char val, int count)
{
__builtin_memset((void __force *) addr, val, count);
diff --git a/include/asm-m68knommu/io.h b/include/asm-m68knommu/io.h
index 8df4cee2a0c..653d9b2d7dd 100644
--- a/include/asm-m68knommu/io.h
+++ b/include/asm-m68knommu/io.h
@@ -165,12 +165,6 @@ static inline void *ioremap_fullcache(unsigned long physaddr, unsigned long size
extern void iounmap(void *addr);
-/* Nothing to do */
-
-#define dma_cache_inv(_start,_size) do { } while (0)
-#define dma_cache_wback(_start,_size) do { } while (0)
-#define dma_cache_wback_inv(_start,_size) do { } while (0)
-
/* Pages to physical address... */
#define page_to_phys(page) ((page - mem_map) << PAGE_SHIFT)
#define page_to_bus(page) ((page - mem_map) << PAGE_SHIFT)
diff --git a/include/asm-mips/io.h b/include/asm-mips/io.h
index 2cd8323c858..e62058b0d28 100644
--- a/include/asm-mips/io.h
+++ b/include/asm-mips/io.h
@@ -554,6 +554,8 @@ static inline void memcpy_toio(volatile void __iomem *dst, const void *src, int
* caches. Dirty lines of the caches may be written back or simply
* be discarded. This operation is necessary before dma operations
* to the memory.
+ *
+ * This API used to be exported; it now is for arch code internal use only.
*/
#ifdef CONFIG_DMA_NONCOHERENT
diff --git a/include/asm-parisc/io.h b/include/asm-parisc/io.h
index 4cc9bcec056..95f00e11c7b 100644
--- a/include/asm-parisc/io.h
+++ b/include/asm-parisc/io.h
@@ -270,11 +270,6 @@ extern void outsl (unsigned long port, const void *src, unsigned long count);
/* IO Port space is : BBiiii where BB is HBA number. */
#define IO_SPACE_LIMIT 0x00ffffff
-
-#define dma_cache_inv(_start,_size) do { flush_kernel_dcache_range(_start,_size); } while (0)
-#define dma_cache_wback(_start,_size) do { flush_kernel_dcache_range(_start,_size); } while (0)
-#define dma_cache_wback_inv(_start,_size) do { flush_kernel_dcache_range(_start,_size); } while (0)
-
/* PA machines have an MM I/O space from 0xf0000000-0xffffffff in 32
* bit mode and from 0xfffffffff0000000-0xfffffffffffffff in 64 bit
* mode (essentially just sign extending. This macro takes in a 32
diff --git a/include/asm-powerpc/io.h b/include/asm-powerpc/io.h
index 0d0589ef8ea..bf14ab4ef4c 100644
--- a/include/asm-powerpc/io.h
+++ b/include/asm-powerpc/io.h
@@ -498,23 +498,6 @@ static inline void name at \
#define writeq writeq
#endif
-#ifdef CONFIG_NOT_COHERENT_CACHE
-
-#define dma_cache_inv(_start,_size) \
- invalidate_dcache_range(_start, (_start + _size))
-#define dma_cache_wback(_start,_size) \
- clean_dcache_range(_start, (_start + _size))
-#define dma_cache_wback_inv(_start,_size) \
- flush_dcache_range(_start, (_start + _size))
-
-#else /* CONFIG_NOT_COHERENT_CACHE */
-
-#define dma_cache_inv(_start,_size) do { } while (0)
-#define dma_cache_wback(_start,_size) do { } while (0)
-#define dma_cache_wback_inv(_start,_size) do { } while (0)
-
-#endif /* !CONFIG_NOT_COHERENT_CACHE */
-
/*
* Convert a physical pointer to a virtual kernel pointer for /dev/mem
* access
diff --git a/include/asm-ppc/io.h b/include/asm-ppc/io.h
index 8f58231a8bc..a0d409a5d80 100644
--- a/include/asm-ppc/io.h
+++ b/include/asm-ppc/io.h
@@ -478,23 +478,6 @@ extern void pci_iounmap(struct pci_dev *dev, void __iomem *);
#include <asm/mpc8260_pci9.h>
#endif
-#ifdef CONFIG_NOT_COHERENT_CACHE
-
-#define dma_cache_inv(_start,_size) \
- invalidate_dcache_range(_start, (_start + _size))
-#define dma_cache_wback(_start,_size) \
- clean_dcache_range(_start, (_start + _size))
-#define dma_cache_wback_inv(_start,_size) \
- flush_dcache_range(_start, (_start + _size))
-
-#else
-
-#define dma_cache_inv(_start,_size) do { } while (0)
-#define dma_cache_wback(_start,_size) do { } while (0)
-#define dma_cache_wback_inv(_start,_size) do { } while (0)
-
-#endif
-
/*
* Convert a physical pointer to a virtual kernel pointer for /dev/mem
* access
diff --git a/include/asm-sh/floppy.h b/include/asm-sh/floppy.h
index 942ade98757..59fbfdc90df 100644
--- a/include/asm-sh/floppy.h
+++ b/include/asm-sh/floppy.h
@@ -213,7 +213,7 @@ static int hard_dma_setup(char *addr, unsigned long size, int mode, int io)
}
#endif
- dma_cache_wback_inv(addr, size);
+ __flush_purge_region(addr, size);
/* actual, physical DMA */
doing_pdma = 0;
diff --git a/include/asm-sh/io.h b/include/asm-sh/io.h
index 1a336cdc75f..6ed34d8eac5 100644
--- a/include/asm-sh/io.h
+++ b/include/asm-sh/io.h
@@ -327,31 +327,6 @@ __ioremap_mode(unsigned long offset, unsigned long size, unsigned long flags)
__iounmap((addr))
/*
- * The caches on some architectures aren't dma-coherent and have need to
- * handle this in software. There are three types of operations that
- * can be applied to dma buffers.
- *
- * - dma_cache_wback_inv(start, size) makes caches and RAM coherent by
- * writing the content of the caches back to memory, if necessary.
- * The function also invalidates the affected part of the caches as
- * necessary before DMA transfers from outside to memory.
- * - dma_cache_inv(start, size) invalidates the affected parts of the
- * caches. Dirty lines of the caches may be written back or simply
- * be discarded. This operation is necessary before dma operations
- * to the memory.
- * - dma_cache_wback(start, size) writes back any dirty lines but does
- * not invalidate the cache. This can be used before DMA reads from
- * memory,
- */
-
-#define dma_cache_wback_inv(_start,_size) \
- __flush_purge_region(_start,_size)
-#define dma_cache_inv(_start,_size) \
- __flush_invalidate_region(_start,_size)
-#define dma_cache_wback(_start,_size) \
- __flush_wback_region(_start,_size)
-
-/*
* Convert a physical pointer to a virtual kernel pointer for /dev/mem
* access
*/
diff --git a/include/asm-sh64/dma-mapping.h b/include/asm-sh64/dma-mapping.h
index de430996020..e661857f98d 100644
--- a/include/asm-sh64/dma-mapping.h
+++ b/include/asm-sh64/dma-mapping.h
@@ -42,7 +42,11 @@ static inline void dma_free_coherent(struct device *dev, size_t size,
static inline void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
enum dma_data_direction dir)
{
- dma_cache_wback_inv((unsigned long)vaddr, size);
+ unsigned long s = (unsigned long) vaddr & L1_CACHE_ALIGN_MASK;
+ unsigned long e = (vaddr + size) & L1_CACHE_ALIGN_MASK;
+
+ for (; s <= e; s += L1_CACHE_BYTES)
+ asm volatile ("ocbp %0, 0" : : "r" (s));
}
static inline dma_addr_t dma_map_single(struct device *dev,
diff --git a/include/asm-sh64/io.h b/include/asm-sh64/io.h
index 3de3ad99f45..7bd7314d38c 100644
--- a/include/asm-sh64/io.h
+++ b/include/asm-sh64/io.h
@@ -182,54 +182,6 @@ unsigned long onchip_remap(unsigned long addr, unsigned long size, const char* n
extern void onchip_unmap(unsigned long vaddr);
/*
- * The caches on some architectures aren't dma-coherent and have need to
- * handle this in software. There are three types of operations that
- * can be applied to dma buffers.
- *
- * - dma_cache_wback_inv(start, size) makes caches and RAM coherent by
- * writing the content of the caches back to memory, if necessary.
- * The function also invalidates the affected part of the caches as
- * necessary before DMA transfers from outside to memory.
- * - dma_cache_inv(start, size) invalidates the affected parts of the
- * caches. Dirty lines of the caches may be written back or simply
- * be discarded. This operation is necessary before dma operations
- * to the memory.
- * - dma_cache_wback(start, size) writes back any dirty lines but does
- * not invalidate the cache. This can be used before DMA reads from
- * memory,
- */
-
-static __inline__ void dma_cache_wback_inv (unsigned long start, unsigned long size)
-{
- unsigned long s = start & L1_CACHE_ALIGN_MASK;
- unsigned long e = (start + size) & L1_CACHE_ALIGN_MASK;
-
- for (; s <= e; s += L1_CACHE_BYTES)
- asm volatile ("ocbp %0, 0" : : "r" (s));
-}
-
-static __inline__ void dma_cache_inv (unsigned long start, unsigned long size)
-{
- // Note that caller has to be careful with overzealous
- // invalidation should there be partial cache lines at the extremities
- // of the specified range
- unsigned long s = start & L1_CACHE_ALIGN_MASK;
- unsigned long e = (start + size) & L1_CACHE_ALIGN_MASK;
-
- for (; s <= e; s += L1_CACHE_BYTES)
- asm volatile ("ocbi %0, 0" : : "r" (s));
-}
-
-static __inline__ void dma_cache_wback (unsigned long start, unsigned long size)
-{
- unsigned long s = start & L1_CACHE_ALIGN_MASK;
- unsigned long e = (start + size) & L1_CACHE_ALIGN_MASK;
-
- for (; s <= e; s += L1_CACHE_BYTES)
- asm volatile ("ocbwb %0, 0" : : "r" (s));
-}
-
-/*
* Convert a physical pointer to a virtual kernel pointer for /dev/mem
* access
*/
diff --git a/include/asm-sparc/io.h b/include/asm-sparc/io.h
index c23e74a0eaa..243bf8e9a05 100644
--- a/include/asm-sparc/io.h
+++ b/include/asm-sparc/io.h
@@ -310,13 +310,6 @@ extern void sbus_iounmap(volatile void __iomem *vaddr, unsigned long size);
#define RTC_PORT(x) (rtc_port + (x))
#define RTC_ALWAYS_BCD 0
-/* Nothing to do */
-/* P3: Only IDE DMA may need these. XXX Verify that it still does... */
-
-#define dma_cache_inv(_start,_size) do { } while (0)
-#define dma_cache_wback(_start,_size) do { } while (0)
-#define dma_cache_wback_inv(_start,_size) do { } while (0)
-
#endif
#define __ARCH_HAS_NO_PAGE_ZERO_MAPPED 1
diff --git a/include/asm-sparc64/io.h b/include/asm-sparc64/io.h
index 9565a892801..cd7ef3097ac 100644
--- a/include/asm-sparc64/io.h
+++ b/include/asm-sparc64/io.h
@@ -474,12 +474,6 @@ extern void pci_iounmap(struct pci_dev *dev, void __iomem *);
#define sbus_iounmap(__addr, __size) \
release_region((unsigned long)(__addr), (__size))
-/* Nothing to do */
-
-#define dma_cache_inv(_start,_size) do { } while (0)
-#define dma_cache_wback(_start,_size) do { } while (0)
-#define dma_cache_wback_inv(_start,_size) do { } while (0)
-
/*
* Convert a physical pointer to a virtual kernel pointer for /dev/mem
* access
diff --git a/include/asm-x86/io_32.h b/include/asm-x86/io_32.h
index e8e0bd64112..4ea7b1ad3c1 100644
--- a/include/asm-x86/io_32.h
+++ b/include/asm-x86/io_32.h
@@ -237,18 +237,9 @@ static inline void flush_write_buffers(void)
__asm__ __volatile__ ("lock; addl $0,0(%%esp)": : :"memory");
}
-#define dma_cache_inv(_start,_size) flush_write_buffers()
-#define dma_cache_wback(_start,_size) flush_write_buffers()
-#define dma_cache_wback_inv(_start,_size) flush_write_buffers()
-
#else
-/* Nothing to do */
-
-#define dma_cache_inv(_start,_size) do { } while (0)
-#define dma_cache_wback(_start,_size) do { } while (0)
-#define dma_cache_wback_inv(_start,_size) do { } while (0)
-#define flush_write_buffers()
+#define flush_write_buffers() do { } while (0)
#endif
diff --git a/include/asm-x86/io_64.h b/include/asm-x86/io_64.h
index 7475095c506..a037b079433 100644
--- a/include/asm-x86/io_64.h
+++ b/include/asm-x86/io_64.h
@@ -249,12 +249,6 @@ void memset_io(volatile void __iomem *a, int b, size_t c);
*/
#define __ISA_IO_base ((char __iomem *)(PAGE_OFFSET))
-/* Nothing to do */
-
-#define dma_cache_inv(_start,_size) do { } while (0)
-#define dma_cache_wback(_start,_size) do { } while (0)
-#define dma_cache_wback_inv(_start,_size) do { } while (0)
-
#define flush_write_buffers()
extern int iommu_bio_merge;