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authorStephen Boyd <sboyd@codeaurora.org>2016-01-20 14:58:35 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-01-20 17:09:18 -0800
commita9aec5881b9d4aca184b29d33484a6a58d23f7f2 (patch)
tree8da654f4e0ce565ebe9c58ee28a0427948979280
parentef5c16b85b2a6d55ae12a8d7125f3908c8d271d4 (diff)
downloadop-kernel-dev-a9aec5881b9d4aca184b29d33484a6a58d23f7f2.zip
op-kernel-dev-a9aec5881b9d4aca184b29d33484a6a58d23f7f2.tar.gz
lib/iomap_copy.c: add __ioread32_copy()
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>
-rw-r--r--include/linux/io.h1
-rw-r--r--lib/iomap_copy.c21
2 files changed, 22 insertions, 0 deletions
diff --git a/include/linux/io.h b/include/linux/io.h
index fffd88d..32403b5 100644
--- a/include/linux/io.h
+++ b/include/linux/io.h
@@ -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
diff --git a/lib/iomap_copy.c b/lib/iomap_copy.c
index 4527e75..b8f1d6c 100644
--- a/lib/iomap_copy.c
+++ b/lib/iomap_copy.c
@@ -42,6 +42,27 @@ 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)
* @from: source (must be 64-bit aligned)
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