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-rw-r--r--arch/arm64/kernel/io.c52
1 files changed, 52 insertions, 0 deletions
diff --git a/arch/arm64/kernel/io.c b/arch/arm64/kernel/io.c
new file mode 100644
index 000000000..fe86ada23
--- /dev/null
+++ b/arch/arm64/kernel/io.c
@@ -0,0 +1,52 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Based on arch/arm/kernel/io.c
+ *
+ * Copyright (C) 2012 ARM Ltd.
+ */
+
+#include <linux/export.h>
+#include <linux/types.h>
+#include <linux/io.h>
+
+/*
+ * This generates a memcpy that works on a from/to address which is aligned to
+ * bits. Count is in terms of the number of bits sized quantities to copy. It
+ * optimizes to use the STR groupings when possible so that it is WC friendly.
+ */
+#define memcpy_toio_aligned(to, from, count, bits) \
+ ({ \
+ volatile u##bits __iomem *_to = to; \
+ const u##bits *_from = from; \
+ size_t _count = count; \
+ const u##bits *_end_from = _from + ALIGN_DOWN(_count, 8); \
+ \
+ for (; _from < _end_from; _from += 8, _to += 8) \
+ __const_memcpy_toio_aligned##bits(_to, _from, 8); \
+ if ((_count % 8) >= 4) { \
+ __const_memcpy_toio_aligned##bits(_to, _from, 4); \
+ _from += 4; \
+ _to += 4; \
+ } \
+ if ((_count % 4) >= 2) { \
+ __const_memcpy_toio_aligned##bits(_to, _from, 2); \
+ _from += 2; \
+ _to += 2; \
+ } \
+ if (_count % 2) \
+ __const_memcpy_toio_aligned##bits(_to, _from, 1); \
+ })
+
+void __iowrite64_copy_full(void __iomem *to, const void *from, size_t count)
+{
+ memcpy_toio_aligned(to, from, count, 64);
+ dgh();
+}
+EXPORT_SYMBOL(__iowrite64_copy_full);
+
+void __iowrite32_copy_full(void __iomem *to, const void *from, size_t count)
+{
+ memcpy_toio_aligned(to, from, count, 32);
+ dgh();
+}
+EXPORT_SYMBOL(__iowrite32_copy_full);