[PATCH v10 18/21] riscv: Enable cpu clock if it is present

Sean Anderson
2020-05-03T02:46:34Z

The cpu clock is probably already enabled if we are executing code (though
we could be executing from a different core). This patch prevents the cpu
clock or its parents from being disabled.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
---
This patch was previously submitted on its own as
https://patchwork.ozlabs.org/patch/1232420/

Changes in v4:
- New

drivers/cpu/riscv_cpu.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)

diff --git a/drivers/cpu/riscv_cpu.c b/drivers/cpu/riscv_cpu.c
index c6ed060abc..9ce58695aa 100644
--- a/drivers/cpu/riscv_cpu.c
+++ b/drivers/cpu/riscv_cpu.c
@@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+ * Copyright (C) 2020, Sean Anderson <seanga2@gmail.com>
*/

#include <clk.h>
@@ -117,6 +118,24 @@ static int riscv_cpu_bind(struct udevice *dev)
return 0;
}

+static int riscv_cpu_probe(struct udevice *dev)
+{
+ int ret = 0;
+ struct clk clk;
+
+ /* Get a clock if it exists */
+ ret = clk_get_by_index(dev, 0, &clk);
+ if (ret)
+ return 0;
+
+ ret = clk_enable(&clk);
+ clk_free(&clk);
+ if (ret == -ENOSYS || ret == -ENOTSUPP)
+ return 0;
+ else
+ return ret;
+}
+
static const struct cpu_ops riscv_cpu_ops = {
.get_desc = riscv_cpu_get_desc,
.get_info = riscv_cpu_get_info,
@@ -133,6 +152,7 @@ U_BOOT_DRIVER(riscv_cpu) = {
.id = UCLASS_CPU,
.of_match = riscv_cpu_ids,
.bind = riscv_cpu_bind,
+ .probe = riscv_cpu_probe,
.ops = &riscv_cpu_ops,
.flags = DM_FLAG_PRE_RELOC,
};
--
2.26.2