From a9aec5881b9d4aca184b29d33484a6a58d23f7f2 Mon Sep 17 00:00:00 2001 From: Stephen Boyd Date: Wed, 20 Jan 2016 14:58:35 -0800 Subject: [PATCH] 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 Cc: Bjorn Andersson Cc: Cc: David Howells Cc: Hauke Mehrtens Cc: Paul Walmsley Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/io.h | 1 + lib/iomap_copy.c | 21 +++++++++++++++++++++ 2 files changed, 22 insertions(+) diff --git a/include/linux/io.h b/include/linux/io.h index fffd88d7f426..32403b5716e5 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 4527e751b5e0..b8f1d6cbb200 100644 --- a/lib/iomap_copy.c +++ b/lib/iomap_copy.c @@ -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) -- 2.20.1