timer: Add generic driver for RISC-V privileged architecture defined timer
RISC-V privileged architecture v1.10 defines a real-time counter,
exposed as a memory-mapped machine-mode register - mtime. mtime must
run at constant frequency, and the platform must provide a mechanism
for determining the timebase of mtime. The mtime register has a
64-bit precision on all RV32, RV64, and RV128 systems.
Different platform may have different implementation of the mtime
block hence an API riscv_get_time() is required by this driver for
platform codes to hide such implementation details. For example,
on some platforms mtime is provided by the CLINT module, while on
some other platforms a simple 'rdtime' can be used to get the timer
counter.
With this timer driver the U-Boot timer functionalities like delay
works correctly now.
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Reviewed-by: Anup Patel <anup@brainfault.org>
diff --git a/drivers/timer/Makefile b/drivers/timer/Makefile
index c4fbab2..d0bf218 100644
--- a/drivers/timer/Makefile
+++ b/drivers/timer/Makefile
@@ -13,6 +13,7 @@
obj-$(CONFIG_DESIGNWARE_APB_TIMER) += dw-apb-timer.o
obj-$(CONFIG_MPC83XX_TIMER) += mpc83xx_timer.o
obj-$(CONFIG_OMAP_TIMER) += omap-timer.o
+obj-$(CONFIG_RISCV_TIMER) += riscv_timer.o
obj-$(CONFIG_ROCKCHIP_TIMER) += rockchip_timer.o
obj-$(CONFIG_SANDBOX_TIMER) += sandbox_timer.o
obj-$(CONFIG_STI_TIMER) += sti-timer.o