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-rw-r--r--arch/arm64/kernel/io.c97
1 files changed, 97 insertions, 0 deletions
diff --git a/arch/arm64/kernel/io.c b/arch/arm64/kernel/io.c
new file mode 100644
index 000000000..aa7a4ec6a
--- /dev/null
+++ b/arch/arm64/kernel/io.c
@@ -0,0 +1,97 @@
+// 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>
+
+/*
+ * Copy data from IO memory space to "real" memory space.
+ */
+void __memcpy_fromio(void *to, const volatile void __iomem *from, size_t count)
+{
+ while (count && !IS_ALIGNED((unsigned long)from, 8)) {
+ *(u8 *)to = __raw_readb(from);
+ from++;
+ to++;
+ count--;
+ }
+
+ while (count >= 8) {
+ *(u64 *)to = __raw_readq(from);
+ from += 8;
+ to += 8;
+ count -= 8;
+ }
+
+ while (count) {
+ *(u8 *)to = __raw_readb(from);
+ from++;
+ to++;
+ count--;
+ }
+}
+EXPORT_SYMBOL(__memcpy_fromio);
+
+/*
+ * Copy data from "real" memory space to IO memory space.
+ */
+void __memcpy_toio(volatile void __iomem *to, const void *from, size_t count)
+{
+ while (count && !IS_ALIGNED((unsigned long)to, 8)) {
+ __raw_writeb(*(u8 *)from, to);
+ from++;
+ to++;
+ count--;
+ }
+
+ while (count >= 8) {
+ __raw_writeq(*(u64 *)from, to);
+ from += 8;
+ to += 8;
+ count -= 8;
+ }
+
+ while (count) {
+ __raw_writeb(*(u8 *)from, to);
+ from++;
+ to++;
+ count--;
+ }
+}
+EXPORT_SYMBOL(__memcpy_toio);
+
+/*
+ * "memset" on IO memory space.
+ */
+void __memset_io(volatile void __iomem *dst, int c, size_t count)
+{
+ u64 qc = (u8)c;
+
+ qc |= qc << 8;
+ qc |= qc << 16;
+ qc |= qc << 32;
+
+ while (count && !IS_ALIGNED((unsigned long)dst, 8)) {
+ __raw_writeb(c, dst);
+ dst++;
+ count--;
+ }
+
+ while (count >= 8) {
+ __raw_writeq(qc, dst);
+ dst += 8;
+ count -= 8;
+ }
+
+ while (count) {
+ __raw_writeb(c, dst);
+ dst++;
+ count--;
+ }
+}
+EXPORT_SYMBOL(__memset_io);