[PATCH v9 18/21] riscv: Enable cpu clock if it is present

[Pragnesh Patel]

Hi Sean,

>-----Original Message-----
>From: U-Boot <u-boot-bounces at lists.denx.de> On Behalf Of Sean Anderson
>Sent: 23 April 2020 08:03
>To: u-boot at lists.denx.de
>Cc: Rick Chen <rickchen36 at gmail.com>; Bin Meng <bmeng.cn at gmail.com>;
>Sean Anderson <seanga2 at gmail.com>
>Subject: [PATCH v9 18/21] riscv: Enable cpu clock if it is present
>
>[External Email] Do not click links or attachments unless you recognize the
>sender and know the content is safe
>
>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 at gmail.com>
>Reviewed-by: Bin Meng <bmeng.cn at 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 at gmail.com>
>+ * Copyright (C) 2020, Sean Anderson <seanga2 at 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;
>+}

can we add clk_set_rate() if clock-frequency is present in cpus node of dts ?
 
>+
> 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,
> };
>--
>2.25.1