riscv: Implement riscv_get_time() API using rdtime instruction
This adds an implementation of riscv_get_time() API that is using
rdtime instruction.
This is the case for S-mode U-Boot, and is useful for processors
that support rdtime in M-mode too.
Signed-off-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index f513f52..7dc6e3f 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -104,4 +104,12 @@
The SiFive CLINT block holds memory-mapped control and status registers
associated with software and timer interrupts.
+config RISCV_RDTIME
+ bool
+ default y if RISCV_SMODE
+ help
+ The provides the riscv_get_time() API that is implemented using the
+ standard rdtime instruction. This is the case for S-mode U-Boot, and
+ is useful for processors that support rdtime in M-mode too.
+
endmenu