Messages in this thread | | | Date | Sat, 30 May 2020 12:41:22 +0100 | From | Marc Zyngier <> | Subject | Re: [PATCH v6 4/6] clocksource/drivers/timer-riscv: Use per-CPU timer interrupt |
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On 2020-05-30 11:07, Anup Patel wrote: > Instead of directly calling RISC-V timer interrupt handler from > RISC-V local interrupt conntroller driver, this patch implements > RISC-V timer interrupt as a per-CPU interrupt using per-CPU APIs > of Linux IRQ subsystem. > > Signed-off-by: Anup Patel <anup.patel@wdc.com> > Reviewed-by: Atish Patra <atish.patra@wdc.com> > --- > arch/riscv/include/asm/irq.h | 2 -- > drivers/clocksource/timer-riscv.c | 41 ++++++++++++++++++++++++++++--- > drivers/irqchip/irq-riscv-intc.c | 8 ------ > 3 files changed, 38 insertions(+), 13 deletions(-) > > diff --git a/arch/riscv/include/asm/irq.h > b/arch/riscv/include/asm/irq.h > index a9e5f07a7e9c..9807ad164015 100644 > --- a/arch/riscv/include/asm/irq.h > +++ b/arch/riscv/include/asm/irq.h > @@ -10,8 +10,6 @@ > #include <linux/interrupt.h> > #include <linux/linkage.h> > > -void riscv_timer_interrupt(void); > - > #include <asm-generic/irq.h> > > #endif /* _ASM_RISCV_IRQ_H */ > diff --git a/drivers/clocksource/timer-riscv.c > b/drivers/clocksource/timer-riscv.c > index c4f15c4068c0..1fe847983f50 100644 > --- a/drivers/clocksource/timer-riscv.c > +++ b/drivers/clocksource/timer-riscv.c > @@ -12,8 +12,11 @@ > #include <linux/cpu.h> > #include <linux/delay.h> > #include <linux/irq.h> > +#include <linux/irqdomain.h> > #include <linux/sched_clock.h> > #include <linux/io-64-nonatomic-lo-hi.h> > +#include <linux/interrupt.h> > +#include <linux/of_irq.h> > #include <asm/smp.h> > #include <asm/sbi.h> > > @@ -39,6 +42,7 @@ static int riscv_clock_next_event(unsigned long > delta, > return 0; > } > > +static unsigned int riscv_clock_event_irq; > static DEFINE_PER_CPU(struct clock_event_device, riscv_clock_event) = > { > .name = "riscv_timer_clockevent", > .features = CLOCK_EVT_FEAT_ONESHOT, > @@ -74,30 +78,36 @@ static int riscv_timer_starting_cpu(unsigned int > cpu) > struct clock_event_device *ce = per_cpu_ptr(&riscv_clock_event, cpu); > > ce->cpumask = cpumask_of(cpu); > + ce->irq = riscv_clock_event_irq; > clockevents_config_and_register(ce, riscv_timebase, 100, 0x7fffffff); > > - csr_set(CSR_IE, IE_TIE); > + enable_percpu_irq(riscv_clock_event_irq, > + irq_get_trigger_type(riscv_clock_event_irq)); > return 0; > } > > static int riscv_timer_dying_cpu(unsigned int cpu) > { > - csr_clear(CSR_IE, IE_TIE); > + disable_percpu_irq(riscv_clock_event_irq); > return 0; > } > > /* called directly from the low-level interrupt handler */ > -void riscv_timer_interrupt(void) > +static irqreturn_t riscv_timer_interrupt(int irq, void *dev_id) > { > struct clock_event_device *evdev = this_cpu_ptr(&riscv_clock_event); > > csr_clear(CSR_IE, IE_TIE); > evdev->event_handler(evdev); > + > + return IRQ_HANDLED; > } > > static int __init riscv_timer_init_dt(struct device_node *n) > { > int cpuid, hartid, error; > + struct device_node *child; > + struct irq_domain *domain; > > hartid = riscv_of_processor_hartid(n); > if (hartid < 0) { > @@ -115,6 +125,23 @@ static int __init riscv_timer_init_dt(struct > device_node *n) > if (cpuid != smp_processor_id()) > return 0; > > + domain = NULL; > + for_each_child_of_node(n, child) { > + domain = irq_find_host(child); > + if (domain) > + break; > + }
This is a bit clumsy, and probably better written as:
child = of_get_compatible(n, "riscv,cpu-intc"); if (!child) { error out } domain = irq_find_host(child);
It would be even better if each CPU would have its per-CPU interrupt controller designated as such (with an interrupt-parent property), meaning that you wouldn't have to do anything at all.
Too late for that anyway.
M. -- Jazz is not dead. It just smells funny...
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