1 files changed, 38 insertions, 0 deletions
diff --git a/arch/riscv/lib/rdtime.c b/arch/riscv/lib/rdtime.c
new file mode 100644
index 0000000000..e128d7fce6
--- /dev/null
+++ b/arch/riscv/lib/rdtime.c
@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018, Anup Patel <anup@brainfault.org>
+ * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+ *
+ * The riscv_get_time() API implementation that is using the
+ * standard rdtime instruction.
+ */
+
+#include <common.h>
+
+/* Implement the API required by RISC-V timer driver */
+int riscv_get_time(u64 *time)
+{
+#ifdef CONFIG_64BIT
+	u64 n;
+
+	__asm__ __volatile__ (
+		"rdtime %0"
+		: "=r" (n));
+
+	*time = n;
+#else
+	u32 lo, hi, tmp;
+
+	__asm__ __volatile__ (
+		"1:\n"
+		"rdtimeh %0\n"
+		"rdtime %1\n"
+		"rdtimeh %2\n"
+		"bne %0, %2, 1b"
+		: "=&r" (hi), "=&r" (lo), "=&r" (tmp));
+
+	*time = ((u64)hi << 32) | lo;
+#endif
+
+	return 0;
+}