Commit 22ae813b authored by Brice Goglin's avatar Brice Goglin Committed by Linus Torvalds

[PATCH] add __iowrite64_copy

Introduce __iowrite64_copy.  It will be used by the Myri-10G Ethernet
driver to post requests to the NIC.  This driver will be submitted soon.

__iowrite64_copy copies to I/O memory in units of 64 bits when possible (on
64 bit architectures).  It reverts to __iowrite32_copy on 32 bit
Signed-off-by: 's avatarBrice Goglin <>
Signed-off-by: 's avatarAndrew Morton <>
Signed-off-by: 's avatarLinus Torvalds <>
parent 34641a58
......@@ -21,5 +21,6 @@
#include <asm/io.h>
void __iowrite32_copy(void __iomem *to, const void *from, size_t count);
void __iowrite64_copy(void __iomem *to, const void *from, size_t count);
#endif /* _LINUX_IO_H */
......@@ -40,3 +40,31 @@ void __attribute__((weak)) __iowrite32_copy(void __iomem *to,
__raw_writel(*src++, dst++);
* __iowrite64_copy - copy data to MMIO space, in 64-bit or 32-bit units
* @to: destination, in MMIO space (must be 64-bit aligned)
* @from: source (must be 64-bit aligned)
* @count: number of 64-bit quantities to copy
* Copy data from kernel space to MMIO space, in units of 32 or 64 bits at a
* time. Order of access is not guaranteed, nor is a memory barrier
* performed afterwards.
void __attribute__((weak)) __iowrite64_copy(void __iomem *to,
const void *from,
size_t count)
#ifdef CONFIG_64BIT
u64 __iomem *dst = to;
const u64 *src = from;
const u64 *end = src + count;
while (src < end)
__raw_writeq(*src++, dst++);
__iowrite32_copy(to, from, count * 2);
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