Some drivers need to read data out of iomem areas 32-bits at a
time. Add an API to do this.
Cc: Bjorn Andersson <bjorn.andersson@xxxxxxxxxxxxxx>
Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>
---
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 de64c1e53612..72c35e0a41d1 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
@@ -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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