LoongArch: Add atomic/locking headers

Add common headers (atomic, bitops, barrier and locking) for basic
LoongArch support.

Reviewed-by: WANG Xuerui <git@xen0n.name>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

1 files changed, 34 insertions, 0 deletions

diff --git a/arch/loongarch/include/asm/bitrev.h b/arch/loongarch/include/asm/bitrev.h
new file mode 100644
index 000000000000..46f275b9cdf7
--- /dev/null
+++ b/arch/loongarch/include/asm/bitrev.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#ifndef __LOONGARCH_ASM_BITREV_H__
+#define __LOONGARCH_ASM_BITREV_H__
+
+#include <linux/swab.h>
+
+static __always_inline __attribute_const__ u32 __arch_bitrev32(u32 x)
+{
+	u32 ret;
+
+	asm("bitrev.4b	%0, %1" : "=r"(ret) : "r"(__swab32(x)));
+	return ret;
+}
+
+static __always_inline __attribute_const__ u16 __arch_bitrev16(u16 x)
+{
+	u16 ret;
+
+	asm("bitrev.4b	%0, %1" : "=r"(ret) : "r"(__swab16(x)));
+	return ret;
+}
+
+static __always_inline __attribute_const__ u8 __arch_bitrev8(u8 x)
+{
+	u8 ret;
+
+	asm("bitrev.4b	%0, %1" : "=r"(ret) : "r"(x));
+	return ret;
+}
+
+#endif /* __LOONGARCH_ASM_BITREV_H__ */