[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
architectures.
Signed-off-by: Brice Goglin <brice@myri.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/lib/iomap_copy.c b/lib/iomap_copy.c
index 351045f..864fc5e 100644
--- a/lib/iomap_copy.c
+++ b/lib/iomap_copy.c
@@ -40,3 +40,31 @@
__raw_writel(*src++, dst++);
}
EXPORT_SYMBOL_GPL(__iowrite32_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)
+ * @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++);
+#else
+ __iowrite32_copy(to, from, count * 2);
+#endif
+}
+
+EXPORT_SYMBOL_GPL(__iowrite64_copy);