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lib/iomap_copy.c: add __ioread32_copy()

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Some drivers need to read data out of iomem areas 32-bits at a time.
Add an API to do this.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Cc: <zajec5@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Cc: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Stephen Boyd 2016-01-20 14:58:35 -08:00 committed by Linus Torvalds
parent ef5c16b85b
commit a9aec5881b
2 changed files with 22 additions and 0 deletions
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1
include/linux/io.h
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@ -29,6 +29,7 @@ struct device;
struct resource;
__visible void __iowrite32_copy(void __iomem *to, const void *from, size_t count);
void __ioread32_copy(void *to, const void __iomem *from, size_t count);
void __iowrite64_copy(void __iomem *to, const void *from, size_t count);
#ifdef CONFIG_MMU

21
lib/iomap_copy.c
View File

@ -41,6 +41,27 @@ void __attribute__((weak)) __iowrite32_copy(void __iomem *to,
}
EXPORT_SYMBOL_GPL(__iowrite32_copy);
/**
* __ioread32_copy - copy data from MMIO space, in 32-bit units
* @to: destination (must be 32-bit aligned)
* @from: source, in MMIO space (must be 32-bit aligned)
* @count: number of 32-bit quantities to copy
*
* Copy data from MMIO space to kernel space, in units of 32 bits at a
* time. Order of access is not guaranteed, nor is a memory barrier
* performed afterwards.
*/
void __ioread32_copy(void *to, const void __iomem *from, size_t count)
{
u32 *dst = to;
const u32 __iomem *src = from;
const u32 __iomem *end = src + count;
while (src < end)
*dst++ = __raw_readl(src++);
}
EXPORT_SYMBOL_GPL(__ioread32_copy);
/**
* __iowrite64_copy - copy data to MMIO space, in 64-bit or 32-bit units
* @to: destination, in MMIO space (must be 64-bit aligned)