linux-kernel - Re: [PATCH 06/15] riscv: cleanup the default power off implementation

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Message-ID: <CAAhSdy1DotXOmo472pXDmRny1Zt11eSH4soG_tYaAALrYzVgBw@mail.gmail.com>
Date:   Fri, 18 Oct 2019 08:23:59 +0530
From:   Anup Patel <anup@...infault.org>
To:     Christoph Hellwig <hch@....de>
Cc:     Palmer Dabbelt <palmer@...ive.com>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Atish Patra <atish.patra@....com>,
        Damien Le Moal <damien.lemoal@....com>,
        linux-riscv <linux-riscv@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org List" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 06/15] riscv: cleanup the default power off implementation

On Thu, Oct 17, 2019 at 11:08 PM Christoph Hellwig <hch@....de> wrote:
>
> Move the sbi poweroff to a separate function and file that is only
> compiled if CONFIG_SBI is set.  Provide a new default fallback
> power off that just sits in a wfi loop to save some power.
>
> Signed-off-by: Christoph Hellwig <hch@....de>
> Reviewed-by: Atish Patra <atish.patra@....com>
> ---
>  arch/riscv/kernel/Makefile |  1 +
>  arch/riscv/kernel/reset.c  |  5 ++---
>  arch/riscv/kernel/sbi.c    | 17 +++++++++++++++++
>  3 files changed, 20 insertions(+), 3 deletions(-)
>  create mode 100644 arch/riscv/kernel/sbi.c
>
> diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
> index 696020ff72db..d8c35fa93cc6 100644
> --- a/arch/riscv/kernel/Makefile
> +++ b/arch/riscv/kernel/Makefile
> @@ -41,5 +41,6 @@ obj-$(CONFIG_DYNAMIC_FTRACE)  += mcount-dyn.o
>  obj-$(CONFIG_PERF_EVENTS)      += perf_event.o
>  obj-$(CONFIG_PERF_EVENTS)      += perf_callchain.o
>  obj-$(CONFIG_HAVE_PERF_REGS)   += perf_regs.o
> +obj-$(CONFIG_RISCV_SBI)                += sbi.o
>
>  clean:
> diff --git a/arch/riscv/kernel/reset.c b/arch/riscv/kernel/reset.c
> index d0fe623bfb8f..5e4e69859af1 100644
> --- a/arch/riscv/kernel/reset.c
> +++ b/arch/riscv/kernel/reset.c
> @@ -4,12 +4,11 @@
>   */
>
>  #include <linux/reboot.h>
> -#include <asm/sbi.h>
>
>  static void default_power_off(void)
>  {
> -       sbi_shutdown();
> -       while (1);
> +       while (1)
> +               wait_for_interrupt();
>  }
>
>  void (*pm_power_off)(void) = default_power_off;
> diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c
> new file mode 100644
> index 000000000000..f6c7c3e82d28
> --- /dev/null
> +++ b/arch/riscv/kernel/sbi.c
> @@ -0,0 +1,17 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +
> +#include <linux/init.h>
> +#include <linux/pm.h>
> +#include <asm/sbi.h>
> +
> +static void sbi_power_off(void)
> +{
> +       sbi_shutdown();
> +}
> +
> +static int __init sbi_init(void)
> +{
> +       pm_power_off = sbi_power_off;
> +       return 0;
> +}
> +early_initcall(sbi_init);
> --
> 2.20.1
>
>
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv

LGTM.

Reviewed-by: Anup Patel <anup@...infault.org>

Regards,
Anup

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