diff mbox series

[v10,1/8] RISC-V: Enable CPU_IDLE drivers

Message ID 20220126114452.692512-2-apatel@ventanamicro.com (mailing list archive)
State New, archived
Headers show
Series RISC-V CPU Idle Support | expand

Commit Message

Anup Patel Jan. 26, 2022, 11:44 a.m. UTC 
From: Anup Patel <anup.patel@wdc.com>

We force select CPU_PM and provide asm/cpuidle.h so that we can
use CPU IDLE drivers for Linux RISC-V kernel.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Anup Patel <apatel@vetanamicro.com>
---
 arch/riscv/Kconfig                |  7 +++++++
 arch/riscv/configs/defconfig      |  1 +
 arch/riscv/configs/rv32_defconfig |  1 +
 arch/riscv/include/asm/cpuidle.h  | 24 ++++++++++++++++++++++++
 arch/riscv/kernel/process.c       |  3 ++-
 5 files changed, 35 insertions(+), 1 deletion(-)
 create mode 100644 arch/riscv/include/asm/cpuidle.h

Comments

Guo Ren Feb. 8, 2022, 6:16 a.m. UTC | #1 
Reviewed-by: Guo Ren <guoren@kernel.org>

small questions:

On Wed, Jan 26, 2022 at 7:46 PM Anup Patel <apatel@ventanamicro.com> wrote:
>
> From: Anup Patel <anup.patel@wdc.com>
>
> We force select CPU_PM and provide asm/cpuidle.h so that we can
> use CPU IDLE drivers for Linux RISC-V kernel.
>
> Signed-off-by: Anup Patel <anup.patel@wdc.com>
> Signed-off-by: Anup Patel <apatel@vetanamicro.com>
> ---
>  arch/riscv/Kconfig                |  7 +++++++
>  arch/riscv/configs/defconfig      |  1 +
>  arch/riscv/configs/rv32_defconfig |  1 +
>  arch/riscv/include/asm/cpuidle.h  | 24 ++++++++++++++++++++++++
>  arch/riscv/kernel/process.c       |  3 ++-
>  5 files changed, 35 insertions(+), 1 deletion(-)
>  create mode 100644 arch/riscv/include/asm/cpuidle.h
>
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 5adcbd9b5e88..76976d12b463 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -46,6 +46,7 @@ config RISCV
>         select CLONE_BACKWARDS
>         select CLINT_TIMER if !MMU
>         select COMMON_CLK
> +       select CPU_PM if CPU_IDLE
>         select EDAC_SUPPORT
>         select GENERIC_ARCH_TOPOLOGY if SMP
>         select GENERIC_ATOMIC64 if !64BIT
> @@ -547,4 +548,10 @@ source "kernel/power/Kconfig"
>
>  endmenu
>
> +menu "CPU Power Management"
> +
> +source "drivers/cpuidle/Kconfig"
> +
> +endmenu
> +
>  source "arch/riscv/kvm/Kconfig"
> diff --git a/arch/riscv/configs/defconfig b/arch/riscv/configs/defconfig
> index f120fcc43d0a..a5e0482a4969 100644
> --- a/arch/riscv/configs/defconfig
> +++ b/arch/riscv/configs/defconfig
> @@ -20,6 +20,7 @@ CONFIG_SOC_SIFIVE=y
>  CONFIG_SOC_VIRT=y
>  CONFIG_SMP=y
>  CONFIG_HOTPLUG_CPU=y
> +CONFIG_CPU_IDLE=y
>  CONFIG_VIRTUALIZATION=y
>  CONFIG_KVM=m
>  CONFIG_JUMP_LABEL=y
> diff --git a/arch/riscv/configs/rv32_defconfig b/arch/riscv/configs/rv32_defconfig
> index 8b56a7f1eb06..d1b87db54d68 100644
> --- a/arch/riscv/configs/rv32_defconfig
> +++ b/arch/riscv/configs/rv32_defconfig
> @@ -20,6 +20,7 @@ CONFIG_SOC_VIRT=y
>  CONFIG_ARCH_RV32I=y
>  CONFIG_SMP=y
>  CONFIG_HOTPLUG_CPU=y
> +CONFIG_CPU_IDLE=y
>  CONFIG_VIRTUALIZATION=y
>  CONFIG_KVM=m
>  CONFIG_JUMP_LABEL=y
> diff --git a/arch/riscv/include/asm/cpuidle.h b/arch/riscv/include/asm/cpuidle.h
> new file mode 100644
> index 000000000000..71fdc607d4bc
> --- /dev/null
> +++ b/arch/riscv/include/asm/cpuidle.h
> @@ -0,0 +1,24 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2021 Allwinner Ltd
> + * Copyright (C) 2021 Western Digital Corporation or its affiliates.
> + */
> +
> +#ifndef _ASM_RISCV_CPUIDLE_H
> +#define _ASM_RISCV_CPUIDLE_H
> +
> +#include <asm/barrier.h>
> +#include <asm/processor.h>
> +
> +static inline void cpu_do_idle(void)
> +{
> +       /*
> +        * Add mb() here to ensure that all
> +        * IO/MEM accesses are completed prior
> +        * to entering WFI.
> +        */
> +       mb();
I think it's a separate fixup.

> +       wait_for_interrupt();
> +}
> +
> +#endif
> diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
> index 03ac3aa611f5..504b496787aa 100644
> --- a/arch/riscv/kernel/process.c
> +++ b/arch/riscv/kernel/process.c
> @@ -23,6 +23,7 @@
>  #include <asm/string.h>
>  #include <asm/switch_to.h>
>  #include <asm/thread_info.h>
> +#include <asm/cpuidle.h>
>
>  register unsigned long gp_in_global __asm__("gp");
>
> @@ -37,7 +38,7 @@ extern asmlinkage void ret_from_kernel_thread(void);
>
>  void arch_cpu_idle(void)
>  {
maybe below is enough.
+ mb();
   wait_for_interrupt();

> -       wait_for_interrupt();
> +       cpu_do_idle();


>         raw_local_irq_enable();
>  }
>
> --
> 2.25.1
>
>
> --
> kvm-riscv mailing list
> kvm-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kvm-riscv
Anup Patel Feb. 9, 2022, 5:15 a.m. UTC | #2 
On Tue, Feb 8, 2022 at 11:46 AM Guo Ren <guoren@kernel.org> wrote:
>
> Reviewed-by: Guo Ren <guoren@kernel.org>
>
> small questions:
>
> On Wed, Jan 26, 2022 at 7:46 PM Anup Patel <apatel@ventanamicro.com> wrote:
> >
> > From: Anup Patel <anup.patel@wdc.com>
> >
> > We force select CPU_PM and provide asm/cpuidle.h so that we can
> > use CPU IDLE drivers for Linux RISC-V kernel.
> >
> > Signed-off-by: Anup Patel <anup.patel@wdc.com>
> > Signed-off-by: Anup Patel <apatel@vetanamicro.com>
> > ---
> >  arch/riscv/Kconfig                |  7 +++++++
> >  arch/riscv/configs/defconfig      |  1 +
> >  arch/riscv/configs/rv32_defconfig |  1 +
> >  arch/riscv/include/asm/cpuidle.h  | 24 ++++++++++++++++++++++++
> >  arch/riscv/kernel/process.c       |  3 ++-
> >  5 files changed, 35 insertions(+), 1 deletion(-)
> >  create mode 100644 arch/riscv/include/asm/cpuidle.h
> >
> > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> > index 5adcbd9b5e88..76976d12b463 100644
> > --- a/arch/riscv/Kconfig
> > +++ b/arch/riscv/Kconfig
> > @@ -46,6 +46,7 @@ config RISCV
> >         select CLONE_BACKWARDS
> >         select CLINT_TIMER if !MMU
> >         select COMMON_CLK
> > +       select CPU_PM if CPU_IDLE
> >         select EDAC_SUPPORT
> >         select GENERIC_ARCH_TOPOLOGY if SMP
> >         select GENERIC_ATOMIC64 if !64BIT
> > @@ -547,4 +548,10 @@ source "kernel/power/Kconfig"
> >
> >  endmenu
> >
> > +menu "CPU Power Management"
> > +
> > +source "drivers/cpuidle/Kconfig"
> > +
> > +endmenu
> > +
> >  source "arch/riscv/kvm/Kconfig"
> > diff --git a/arch/riscv/configs/defconfig b/arch/riscv/configs/defconfig
> > index f120fcc43d0a..a5e0482a4969 100644
> > --- a/arch/riscv/configs/defconfig
> > +++ b/arch/riscv/configs/defconfig
> > @@ -20,6 +20,7 @@ CONFIG_SOC_SIFIVE=y
> >  CONFIG_SOC_VIRT=y
> >  CONFIG_SMP=y
> >  CONFIG_HOTPLUG_CPU=y
> > +CONFIG_CPU_IDLE=y
> >  CONFIG_VIRTUALIZATION=y
> >  CONFIG_KVM=m
> >  CONFIG_JUMP_LABEL=y
> > diff --git a/arch/riscv/configs/rv32_defconfig b/arch/riscv/configs/rv32_defconfig
> > index 8b56a7f1eb06..d1b87db54d68 100644
> > --- a/arch/riscv/configs/rv32_defconfig
> > +++ b/arch/riscv/configs/rv32_defconfig
> > @@ -20,6 +20,7 @@ CONFIG_SOC_VIRT=y
> >  CONFIG_ARCH_RV32I=y
> >  CONFIG_SMP=y
> >  CONFIG_HOTPLUG_CPU=y
> > +CONFIG_CPU_IDLE=y
> >  CONFIG_VIRTUALIZATION=y
> >  CONFIG_KVM=m
> >  CONFIG_JUMP_LABEL=y
> > diff --git a/arch/riscv/include/asm/cpuidle.h b/arch/riscv/include/asm/cpuidle.h
> > new file mode 100644
> > index 000000000000..71fdc607d4bc
> > --- /dev/null
> > +++ b/arch/riscv/include/asm/cpuidle.h
> > @@ -0,0 +1,24 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * Copyright (C) 2021 Allwinner Ltd
> > + * Copyright (C) 2021 Western Digital Corporation or its affiliates.
> > + */
> > +
> > +#ifndef _ASM_RISCV_CPUIDLE_H
> > +#define _ASM_RISCV_CPUIDLE_H
> > +
> > +#include <asm/barrier.h>
> > +#include <asm/processor.h>
> > +
> > +static inline void cpu_do_idle(void)
> > +{
> > +       /*
> > +        * Add mb() here to ensure that all
> > +        * IO/MEM accesses are completed prior
> > +        * to entering WFI.
> > +        */
> > +       mb();
> I think it's a separate fixup.

This one is tricky to move as separate fixup because there
is no cpu_do_idle() until this patch adds it.

If we deliberately have a separate patch for "mb()" then it
will be only fixing cpu_do_idle() function added by previous
patch in the same series.

Regards,
Anup

>
> > +       wait_for_interrupt();
> > +}
> > +
> > +#endif
> > diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
> > index 03ac3aa611f5..504b496787aa 100644
> > --- a/arch/riscv/kernel/process.c
> > +++ b/arch/riscv/kernel/process.c
> > @@ -23,6 +23,7 @@
> >  #include <asm/string.h>
> >  #include <asm/switch_to.h>
> >  #include <asm/thread_info.h>
> > +#include <asm/cpuidle.h>
> >
> >  register unsigned long gp_in_global __asm__("gp");
> >
> > @@ -37,7 +38,7 @@ extern asmlinkage void ret_from_kernel_thread(void);
> >
> >  void arch_cpu_idle(void)
> >  {
> maybe below is enough.
> + mb();
>    wait_for_interrupt();
>
> > -       wait_for_interrupt();
> > +       cpu_do_idle();
>
>
> >         raw_local_irq_enable();
> >  }
> >
> > --
> > 2.25.1
> >
> >
> > --
> > kvm-riscv mailing list
> > kvm-riscv@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/kvm-riscv
>
>
>
> --
> Best Regards
>  Guo Ren
>
> ML: https://lore.kernel.org/linux-csky/
Anup Patel Feb. 9, 2022, 5:20 a.m. UTC | #3 
On Tue, Feb 8, 2022 at 11:46 AM Guo Ren <guoren@kernel.org> wrote:
>
> Reviewed-by: Guo Ren <guoren@kernel.org>
>
> small questions:
>
> On Wed, Jan 26, 2022 at 7:46 PM Anup Patel <apatel@ventanamicro.com> wrote:
> >
> > From: Anup Patel <anup.patel@wdc.com>
> >
> > We force select CPU_PM and provide asm/cpuidle.h so that we can
> > use CPU IDLE drivers for Linux RISC-V kernel.
> >
> > Signed-off-by: Anup Patel <anup.patel@wdc.com>
> > Signed-off-by: Anup Patel <apatel@vetanamicro.com>
> > ---
> >  arch/riscv/Kconfig                |  7 +++++++
> >  arch/riscv/configs/defconfig      |  1 +
> >  arch/riscv/configs/rv32_defconfig |  1 +
> >  arch/riscv/include/asm/cpuidle.h  | 24 ++++++++++++++++++++++++
> >  arch/riscv/kernel/process.c       |  3 ++-
> >  5 files changed, 35 insertions(+), 1 deletion(-)
> >  create mode 100644 arch/riscv/include/asm/cpuidle.h
> >
> > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> > index 5adcbd9b5e88..76976d12b463 100644
> > --- a/arch/riscv/Kconfig
> > +++ b/arch/riscv/Kconfig
> > @@ -46,6 +46,7 @@ config RISCV
> >         select CLONE_BACKWARDS
> >         select CLINT_TIMER if !MMU
> >         select COMMON_CLK
> > +       select CPU_PM if CPU_IDLE
> >         select EDAC_SUPPORT
> >         select GENERIC_ARCH_TOPOLOGY if SMP
> >         select GENERIC_ATOMIC64 if !64BIT
> > @@ -547,4 +548,10 @@ source "kernel/power/Kconfig"
> >
> >  endmenu
> >
> > +menu "CPU Power Management"
> > +
> > +source "drivers/cpuidle/Kconfig"
> > +
> > +endmenu
> > +
> >  source "arch/riscv/kvm/Kconfig"
> > diff --git a/arch/riscv/configs/defconfig b/arch/riscv/configs/defconfig
> > index f120fcc43d0a..a5e0482a4969 100644
> > --- a/arch/riscv/configs/defconfig
> > +++ b/arch/riscv/configs/defconfig
> > @@ -20,6 +20,7 @@ CONFIG_SOC_SIFIVE=y
> >  CONFIG_SOC_VIRT=y
> >  CONFIG_SMP=y
> >  CONFIG_HOTPLUG_CPU=y
> > +CONFIG_CPU_IDLE=y
> >  CONFIG_VIRTUALIZATION=y
> >  CONFIG_KVM=m
> >  CONFIG_JUMP_LABEL=y
> > diff --git a/arch/riscv/configs/rv32_defconfig b/arch/riscv/configs/rv32_defconfig
> > index 8b56a7f1eb06..d1b87db54d68 100644
> > --- a/arch/riscv/configs/rv32_defconfig
> > +++ b/arch/riscv/configs/rv32_defconfig
> > @@ -20,6 +20,7 @@ CONFIG_SOC_VIRT=y
> >  CONFIG_ARCH_RV32I=y
> >  CONFIG_SMP=y
> >  CONFIG_HOTPLUG_CPU=y
> > +CONFIG_CPU_IDLE=y
> >  CONFIG_VIRTUALIZATION=y
> >  CONFIG_KVM=m
> >  CONFIG_JUMP_LABEL=y
> > diff --git a/arch/riscv/include/asm/cpuidle.h b/arch/riscv/include/asm/cpuidle.h
> > new file mode 100644
> > index 000000000000..71fdc607d4bc
> > --- /dev/null
> > +++ b/arch/riscv/include/asm/cpuidle.h
> > @@ -0,0 +1,24 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * Copyright (C) 2021 Allwinner Ltd
> > + * Copyright (C) 2021 Western Digital Corporation or its affiliates.
> > + */
> > +
> > +#ifndef _ASM_RISCV_CPUIDLE_H
> > +#define _ASM_RISCV_CPUIDLE_H
> > +
> > +#include <asm/barrier.h>
> > +#include <asm/processor.h>
> > +
> > +static inline void cpu_do_idle(void)
> > +{
> > +       /*
> > +        * Add mb() here to ensure that all
> > +        * IO/MEM accesses are completed prior
> > +        * to entering WFI.
> > +        */
> > +       mb();
> I think it's a separate fixup.
>
> > +       wait_for_interrupt();
> > +}
> > +
> > +#endif
> > diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
> > index 03ac3aa611f5..504b496787aa 100644
> > --- a/arch/riscv/kernel/process.c
> > +++ b/arch/riscv/kernel/process.c
> > @@ -23,6 +23,7 @@
> >  #include <asm/string.h>
> >  #include <asm/switch_to.h>
> >  #include <asm/thread_info.h>
> > +#include <asm/cpuidle.h>
> >
> >  register unsigned long gp_in_global __asm__("gp");
> >
> > @@ -37,7 +38,7 @@ extern asmlinkage void ret_from_kernel_thread(void);
> >
> >  void arch_cpu_idle(void)
> >  {
> maybe below is enough.
> + mb();

We can't add "mb()" here because cpu_do_idle() is called
directly from linux/cpuidle.h and arch_cpu_idle() is only
called when CPU idle is disabled.

Regards,
Anup

>    wait_for_interrupt();
>
> > -       wait_for_interrupt();
> > +       cpu_do_idle();
>
>
> >         raw_local_irq_enable();
> >  }
> >
> > --
> > 2.25.1
> >
> >
> > --
> > kvm-riscv mailing list
> > kvm-riscv@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/kvm-riscv
>
>
>
> --
> Best Regards
>  Guo Ren
>
> ML: https://lore.kernel.org/linux-csky/
Guo Ren Feb. 9, 2022, 6 a.m. UTC | #4 
On Wed, Feb 9, 2022 at 1:15 PM Anup Patel <anup@brainfault.org> wrote:
>
> On Tue, Feb 8, 2022 at 11:46 AM Guo Ren <guoren@kernel.org> wrote:
> >
> > Reviewed-by: Guo Ren <guoren@kernel.org>
> >
> > small questions:
> >
> > On Wed, Jan 26, 2022 at 7:46 PM Anup Patel <apatel@ventanamicro.com> wrote:
> > >
> > > From: Anup Patel <anup.patel@wdc.com>
> > >
> > > We force select CPU_PM and provide asm/cpuidle.h so that we can
> > > use CPU IDLE drivers for Linux RISC-V kernel.
> > >
> > > Signed-off-by: Anup Patel <anup.patel@wdc.com>
> > > Signed-off-by: Anup Patel <apatel@vetanamicro.com>
> > > ---
> > >  arch/riscv/Kconfig                |  7 +++++++
> > >  arch/riscv/configs/defconfig      |  1 +
> > >  arch/riscv/configs/rv32_defconfig |  1 +
> > >  arch/riscv/include/asm/cpuidle.h  | 24 ++++++++++++++++++++++++
> > >  arch/riscv/kernel/process.c       |  3 ++-
> > >  5 files changed, 35 insertions(+), 1 deletion(-)
> > >  create mode 100644 arch/riscv/include/asm/cpuidle.h
> > >
> > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> > > index 5adcbd9b5e88..76976d12b463 100644
> > > --- a/arch/riscv/Kconfig
> > > +++ b/arch/riscv/Kconfig
> > > @@ -46,6 +46,7 @@ config RISCV
> > >         select CLONE_BACKWARDS
> > >         select CLINT_TIMER if !MMU
> > >         select COMMON_CLK
> > > +       select CPU_PM if CPU_IDLE
> > >         select EDAC_SUPPORT
> > >         select GENERIC_ARCH_TOPOLOGY if SMP
> > >         select GENERIC_ATOMIC64 if !64BIT
> > > @@ -547,4 +548,10 @@ source "kernel/power/Kconfig"
> > >
> > >  endmenu
> > >
> > > +menu "CPU Power Management"
> > > +
> > > +source "drivers/cpuidle/Kconfig"
> > > +
> > > +endmenu
> > > +
> > >  source "arch/riscv/kvm/Kconfig"
> > > diff --git a/arch/riscv/configs/defconfig b/arch/riscv/configs/defconfig
> > > index f120fcc43d0a..a5e0482a4969 100644
> > > --- a/arch/riscv/configs/defconfig
> > > +++ b/arch/riscv/configs/defconfig
> > > @@ -20,6 +20,7 @@ CONFIG_SOC_SIFIVE=y
> > >  CONFIG_SOC_VIRT=y
> > >  CONFIG_SMP=y
> > >  CONFIG_HOTPLUG_CPU=y
> > > +CONFIG_CPU_IDLE=y
> > >  CONFIG_VIRTUALIZATION=y
> > >  CONFIG_KVM=m
> > >  CONFIG_JUMP_LABEL=y
> > > diff --git a/arch/riscv/configs/rv32_defconfig b/arch/riscv/configs/rv32_defconfig
> > > index 8b56a7f1eb06..d1b87db54d68 100644
> > > --- a/arch/riscv/configs/rv32_defconfig
> > > +++ b/arch/riscv/configs/rv32_defconfig
> > > @@ -20,6 +20,7 @@ CONFIG_SOC_VIRT=y
> > >  CONFIG_ARCH_RV32I=y
> > >  CONFIG_SMP=y
> > >  CONFIG_HOTPLUG_CPU=y
> > > +CONFIG_CPU_IDLE=y
> > >  CONFIG_VIRTUALIZATION=y
> > >  CONFIG_KVM=m
> > >  CONFIG_JUMP_LABEL=y
> > > diff --git a/arch/riscv/include/asm/cpuidle.h b/arch/riscv/include/asm/cpuidle.h
> > > new file mode 100644
> > > index 000000000000..71fdc607d4bc
> > > --- /dev/null
> > > +++ b/arch/riscv/include/asm/cpuidle.h
> > > @@ -0,0 +1,24 @@
> > > +/* SPDX-License-Identifier: GPL-2.0 */
> > > +/*
> > > + * Copyright (C) 2021 Allwinner Ltd
> > > + * Copyright (C) 2021 Western Digital Corporation or its affiliates.
> > > + */
> > > +
> > > +#ifndef _ASM_RISCV_CPUIDLE_H
> > > +#define _ASM_RISCV_CPUIDLE_H
> > > +
> > > +#include <asm/barrier.h>
> > > +#include <asm/processor.h>
> > > +
> > > +static inline void cpu_do_idle(void)
> > > +{
> > > +       /*
> > > +        * Add mb() here to ensure that all
> > > +        * IO/MEM accesses are completed prior
> > > +        * to entering WFI.
> > > +        */
> > > +       mb();
> > I think it's a separate fixup.
>
> This one is tricky to move as separate fixup because there
> is no cpu_do_idle() until this patch adds it.
>
> If we deliberately have a separate patch for "mb()" then it
> will be only fixing cpu_do_idle() function added by previous
> patch in the same series.
You are right, I misunderstood the usage of asm/cpuidle.h.

>
> Regards,
> Anup
>
> >
> > > +       wait_for_interrupt();
> > > +}
> > > +
> > > +#endif
> > > diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
> > > index 03ac3aa611f5..504b496787aa 100644
> > > --- a/arch/riscv/kernel/process.c
> > > +++ b/arch/riscv/kernel/process.c
> > > @@ -23,6 +23,7 @@
> > >  #include <asm/string.h>
> > >  #include <asm/switch_to.h>
> > >  #include <asm/thread_info.h>
> > > +#include <asm/cpuidle.h>
> > >
> > >  register unsigned long gp_in_global __asm__("gp");
> > >
> > > @@ -37,7 +38,7 @@ extern asmlinkage void ret_from_kernel_thread(void);
> > >
> > >  void arch_cpu_idle(void)
> > >  {
> > maybe below is enough.
> > + mb();
> >    wait_for_interrupt();
> >
> > > -       wait_for_interrupt();
> > > +       cpu_do_idle();
> >
> >
> > >         raw_local_irq_enable();
> > >  }
> > >
> > > --
> > > 2.25.1
> > >
> > >
> > > --
> > > kvm-riscv mailing list
> > > kvm-riscv@lists.infradead.org
> > > http://lists.infradead.org/mailman/listinfo/kvm-riscv
> >
> >
> >
> > --
> > Best Regards
> >  Guo Ren
> >
> > ML: https://lore.kernel.org/linux-csky/
diff mbox series

Patch

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 5adcbd9b5e88..76976d12b463 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -46,6 +46,7 @@  config RISCV
 	select CLONE_BACKWARDS
 	select CLINT_TIMER if !MMU
 	select COMMON_CLK
+	select CPU_PM if CPU_IDLE
 	select EDAC_SUPPORT
 	select GENERIC_ARCH_TOPOLOGY if SMP
 	select GENERIC_ATOMIC64 if !64BIT
@@ -547,4 +548,10 @@  source "kernel/power/Kconfig"
 
 endmenu
 
+menu "CPU Power Management"
+
+source "drivers/cpuidle/Kconfig"
+
+endmenu
+
 source "arch/riscv/kvm/Kconfig"
diff --git a/arch/riscv/configs/defconfig b/arch/riscv/configs/defconfig
index f120fcc43d0a..a5e0482a4969 100644
--- a/arch/riscv/configs/defconfig
+++ b/arch/riscv/configs/defconfig
@@ -20,6 +20,7 @@  CONFIG_SOC_SIFIVE=y
 CONFIG_SOC_VIRT=y
 CONFIG_SMP=y
 CONFIG_HOTPLUG_CPU=y
+CONFIG_CPU_IDLE=y
 CONFIG_VIRTUALIZATION=y
 CONFIG_KVM=m
 CONFIG_JUMP_LABEL=y
diff --git a/arch/riscv/configs/rv32_defconfig b/arch/riscv/configs/rv32_defconfig
index 8b56a7f1eb06..d1b87db54d68 100644
--- a/arch/riscv/configs/rv32_defconfig
+++ b/arch/riscv/configs/rv32_defconfig
@@ -20,6 +20,7 @@  CONFIG_SOC_VIRT=y
 CONFIG_ARCH_RV32I=y
 CONFIG_SMP=y
 CONFIG_HOTPLUG_CPU=y
+CONFIG_CPU_IDLE=y
 CONFIG_VIRTUALIZATION=y
 CONFIG_KVM=m
 CONFIG_JUMP_LABEL=y
diff --git a/arch/riscv/include/asm/cpuidle.h b/arch/riscv/include/asm/cpuidle.h
new file mode 100644
index 000000000000..71fdc607d4bc
--- /dev/null
+++ b/arch/riscv/include/asm/cpuidle.h
@@ -0,0 +1,24 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2021 Allwinner Ltd
+ * Copyright (C) 2021 Western Digital Corporation or its affiliates.
+ */
+
+#ifndef _ASM_RISCV_CPUIDLE_H
+#define _ASM_RISCV_CPUIDLE_H
+
+#include <asm/barrier.h>
+#include <asm/processor.h>
+
+static inline void cpu_do_idle(void)
+{
+	/*
+	 * Add mb() here to ensure that all
+	 * IO/MEM accesses are completed prior
+	 * to entering WFI.
+	 */
+	mb();
+	wait_for_interrupt();
+}
+
+#endif
diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
index 03ac3aa611f5..504b496787aa 100644
--- a/arch/riscv/kernel/process.c
+++ b/arch/riscv/kernel/process.c
@@ -23,6 +23,7 @@ 
 #include <asm/string.h>
 #include <asm/switch_to.h>
 #include <asm/thread_info.h>
+#include <asm/cpuidle.h>
 
 register unsigned long gp_in_global __asm__("gp");
 
@@ -37,7 +38,7 @@  extern asmlinkage void ret_from_kernel_thread(void);
 
 void arch_cpu_idle(void)
 {
-	wait_for_interrupt();
+	cpu_do_idle();
 	raw_local_irq_enable();
 }