Messages in this thread Patch in this message | | | Date | Wed, 16 Sep 2020 09:27:40 +0800 | From | "liush" <> | Subject | 回复:[PATCH] cpuidle: add riscv cpuidle driver |
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Hi Palmer,
> > This patch adds a cpuidle driver for systems based RISCV architecture. > > This patch supports state WFI. Other states will be supported in the > > future. > > > > Signed-off-by: liush <liush@allwinnertech.com> > > --- > > arch/riscv/Kconfig | 7 +++++ > > arch/riscv/include/asm/cpuidle.h | 7 +++++ > > arch/riscv/kernel/Makefile | 1 + > > arch/riscv/kernel/cpuidle.c | 8 ++++++ > > drivers/cpuidle/Kconfig | 5 ++++ > > drivers/cpuidle/Kconfig.riscv | 11 ++++++++ > > drivers/cpuidle/Makefile | 4 +++ > > drivers/cpuidle/cpuidle-riscv.c | 55 ++++++++++++++++++++++++++++++++++++++++ > > 8 files changed, 98 insertions(+) > > create mode 100644 arch/riscv/include/asm/cpuidle.h > > create mode 100644 arch/riscv/kernel/cpuidle.c > > create mode 100644 drivers/cpuidle/Kconfig.riscv > > create mode 100644 drivers/cpuidle/cpuidle-riscv.c > > > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > > index df18372..c7ddb9d 100644 > > --- a/arch/riscv/Kconfig > > +++ b/arch/riscv/Kconfig > > @@ -86,6 +86,7 @@ config RISCV > > select SPARSE_IRQ > > select SYSCTL_EXCEPTION_TRACE > > select THREAD_INFO_IN_TASK > > + select CPU_IDLE > > > > config ARCH_MMAP_RND_BITS_MIN > > default 18 if 64BIT > > @@ -407,6 +408,12 @@ config BUILTIN_DTB > > depends on RISCV_M_MODE > > depends on OF > > > > +menu "CPU Power Management" > > + > > +source "drivers/cpuidle/Kconfig" > > + > > +endmenu > > + > > menu "Power management options" > > > > source "kernel/power/Kconfig" > > diff --git a/arch/riscv/include/asm/cpuidle.h b/arch/riscv/include/asm/cpuidle.h > > new file mode 100644 > > index 00000000..2599d2f > > --- /dev/null > > +++ b/arch/riscv/include/asm/cpuidle.h > > @@ -0,0 +1,7 @@ > > +/* SPDX-License-Identifier: GPL-2.0 */ > > +#ifndef __RISCV_CPUIDLE_H > > +#define __RISCV_CPUIDLE_H > > + > +extern void cpu_do_idle(void); > > + > > +#endif > > diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile > > index dc93710..396ba9c 100644 > > --- a/arch/riscv/kernel/Makefile > > +++ b/arch/riscv/kernel/Makefile > > @@ -29,6 +29,7 @@ obj-y += riscv_ksyms.o > > obj-y += stacktrace.o > > obj-y += cacheinfo.o > > obj-y += patch.o > > +obj-y += cpuidle.o
> Presumably we want this to be a Kconfig option, if only to avoid excess size on > the smaller systems?
Thank you for your suggestions. I am considering following Anup's suggestion - delete cpuidle.c and implement cpu_do_idle in cpuidle.h.
> > obj-$(CONFIG_MMU) += vdso.o vdso/ > > > > obj-$(CONFIG_RISCV_M_MODE) += traps_misaligned.o > > diff --git a/arch/riscv/kernel/cpuidle.c b/arch/riscv/kernel/cpuidle.c > > new file mode 100644 > > index 00000000..a3289e7 > > --- /dev/null > > +++ b/arch/riscv/kernel/cpuidle.c > > @@ -0,0 +1,8 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > +#include <asm/cpuidle.h> > > + > > +void cpu_do_idle(void) > > +{ > > + __asm__ __volatile__ ("wfi"); > > +
> We have wait_for_interrupt() that does this already, but it's one line so it > doesn't really matter. Either way, there's an extra newline here.
Thanks, i'll modify it
> Additionally, we have arch_cpu_idle() which is calling cpu_do_idle() on other > platforms. Presumably we should be doing something similar, under the > assumption that we will eventually have cpu_do_idle() hook into CPU idle > drivers here?
Based on your comments, I run a test and found that arch_cpu_idle could be executed normally without enabling the idle driver.Part of the code of the experiment:
+static inline void cpu_do_idle(void) +{ + mb(); + wait_for_interrupt(); +} void arch_cpu_idle(void) { - wait_for_interrupt(); + cpu_do_idle(); local_irq_enable(); } > > +} > > diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig > > index c0aeedd..f6be0fd 100644 > > --- a/drivers/cpuidle/Kconfig > > +++ b/drivers/cpuidle/Kconfig > > @@ -62,6 +62,11 @@ depends on PPC > > source "drivers/cpuidle/Kconfig.powerpc" > > endmenu > > > > +menu "RISCV CPU Idle Drivers" > > +depends on RISCV > > +source "drivers/cpuidle/Kconfig.riscv" > > +endmenu > > + > > config HALTPOLL_CPUIDLE > > tristate "Halt poll cpuidle driver" > > depends on X86 && KVM_GUEST > > diff --git a/drivers/cpuidle/Kconfig.riscv b/drivers/cpuidle/Kconfig.riscv > > new file mode 100644 > > index 00000000..e86d36b > > --- /dev/null > > +++ b/drivers/cpuidle/Kconfig.riscv > > @@ -0,0 +1,11 @@ > > +# SPDX-License-Identifier: GPL-2.0-only > > +# > > +# RISCV CPU Idle drivers > > +# > > +config RISCV_CPUIDLE > > + bool "Generic RISCV CPU idle Driver" > > + select DT_IDLE_STATES > > + select CPU_IDLE_MULTIPLE_DRIVERS > Looks like there's some space/tab issues here. IIRC checkpatch will catch this > sort of thing.
yes, i'll modify it
> > + help > > + Select this option to enable generic cpuidle driver for RISCV. > > + Now only support C0 State. > > diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile > > index 26bbc5e..4c83c4e 100644 > > --- a/drivers/cpuidle/Makefile > > +++ b/drivers/cpuidle/Makefile > > @@ -34,3 +34,7 @@ obj-$(CONFIG_MIPS_CPS_CPUIDLE) += cpuidle-cps.o > > # POWERPC drivers > > obj-$(CONFIG_PSERIES_CPUIDLE) += cpuidle-pseries.o > > obj-$(CONFIG_POWERNV_CPUIDLE) += cpuidle-powernv.o > > + > > +############################################################################### > > +# RISCV drivers > > +obj-$(CONFIG_RISCV_CPUIDLE) += cpuidle-riscv.o > > diff --git a/drivers/cpuidle/cpuidle-riscv.c b/drivers/cpuidle/cpuidle-riscv.c > > new file mode 100644 > > index 00000000..5dddcfa > > --- /dev/null > > +++ b/drivers/cpuidle/cpuidle-riscv.c > > @@ -0,0 +1,55 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > +/* > > + * RISC-V CPU idle driver. > > + * > > + * Copyright (C) 2020-2022 Allwinner Ltd > > + * > > + * Based on code - driver/cpuidle/cpuidle-at91.c > > + * > > + */ > > +#include <linux/cpuidle.h> > > +#include <linux/cpumask.h> > > +#include <linux/cpu_pm.h> > > +#include <linux/kernel.h> > > +#include <linux/module.h> > > +#include <linux/of.h> > > +#include <linux/slab.h> > > +#include <linux/platform_device.h> > > +#include <asm/cpuidle.h> > > + > > +#define MAX_IDLE_STATES 1 > > + > > +/* TODO: Implement deeper idle states */ > > +static int riscv_low_level_suspend_enter(int state) > > +{ > > + return 0;
> As far as I can tell, this driver just doesn't do anything? Assuming that's > the case, it's probably best to just drop everything but cpu_do_idle() until we > have something to exercise this.
Although, the driver in this case is not necessary, it is essential when work in the macro CPU_PM_CPU_IDLE_ENTER_PARAM.And it could also be used for supporting other deeper states in the future. So I think it would be better to keep riscv_low_level_suspend_enter but change it to __weak function.
> > +} > > + > > +/* Actual code that puts the SoC in different idle states */ > > +static int riscv_enter_idle(struct cpuidle_device *dev, > > + struct cpuidle_driver *drv, > > + int index) > > +{ > > + return CPU_PM_CPU_IDLE_ENTER_PARAM(riscv_low_level_suspend_enter, > > + index, 0); > > +} > > + > > +static struct cpuidle_driver riscv_idle_driver = { > > + .name = "riscv_idle", > > + .owner = THIS_MODULE, > > + .states[0] = { > > + .enter = riscv_enter_idle, > > + .exit_latency = 1, > > + .target_residency = 1, > > + .name = "WFI", > > + .desc = "RISCV WFI", > > + }, > > + .state_count = MAX_IDLE_STATES, > > +}; > > + > > +static int __init riscv_cpuidle_init(void) > > +{ > > + return cpuidle_register(&riscv_idle_driver, NULL); > > +} > > + > > +device_initcall(riscv_cpuidle_init);
Regards, liush | |