On Wed, Feb 9, 2022 at 1:15 PM Anup Patel <anup@xxxxxxxxxxxxxx> wrote:
>
> On Tue, Feb 8, 2022 at 11:46 AM Guo Ren <guoren@xxxxxxxxxx> wrote:
> >
> > Reviewed-by: Guo Ren <guoren@xxxxxxxxxx>
> >
> > small questions:
> >
> > On Wed, Jan 26, 2022 at 7:46 PM Anup Patel <apatel@xxxxxxxxxxxxxxxx> wrote:
> > >
> > > From: Anup Patel <anup.patel@xxxxxxx>
> > >
> > > 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@xxxxxxx>
> > > Signed-off-by: Anup Patel <apatel@xxxxxxxxxxxxxxx>
> > > ---
> > > 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@xxxxxxxxxxxxxxxxxxx
> > > http://lists.infradead.org/mailman/listinfo/kvm-riscv
> >
> >
> >
> > --
> > Best Regards
> > Guo Ren
> >
> > ML: https://lore.kernel.org/linux-csky/
--
Best Regards
Guo Ren
ML: https://lore.kernel.org/linux-csky/
