On Thu, May 21, 2020 at 6:34 AM Anup Patel <anup.pa...@wdc.com> 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.pa...@wdc.com> > --- > arch/riscv/include/asm/irq.h | 2 -- > drivers/clocksource/timer-riscv.c | 30 +++++++++++++++++++++++++++--- > drivers/irqchip/irq-riscv-intc.c | 8 -------- > 3 files changed, 27 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..5fb7c5ba5c91 100644 > --- a/drivers/clocksource/timer-riscv.c > +++ b/drivers/clocksource/timer-riscv.c > @@ -14,6 +14,9 @@ > #include <linux/irq.h> > #include <linux/sched_clock.h> > #include <linux/io-64-nonatomic-lo-hi.h> > +#include <linux/irqchip/irq-riscv-intc.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 +78,35 @@ 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 of_phandle_args oirq; > > hartid = riscv_of_processor_hartid(n); > if (hartid < 0) { > @@ -115,6 +124,13 @@ static int __init riscv_timer_init_dt(struct device_node > *n) > if (cpuid != smp_processor_id()) > return 0; > > + oirq.np = riscv_of_intc_domain_node(); > + oirq.args_count = 1; > + oirq.args[0] = RV_IRQ_TIMER; > + riscv_clock_event_irq = irq_create_of_mapping(&oirq); > + if (!riscv_clock_event_irq) > + return -ENODEV; > +
As the error case will result in a system without a clock, a warning message may be a good option. > pr_info("%s: Registering clocksource cpuid [%d] hartid [%d]\n", > __func__, cpuid, hartid); > error = clocksource_register_hz(&riscv_clocksource, riscv_timebase); > @@ -126,6 +142,14 @@ static int __init riscv_timer_init_dt(struct device_node > *n) > > sched_clock_register(riscv_sched_clock, 64, riscv_timebase); > > + error = request_percpu_irq(riscv_clock_event_irq, > + riscv_timer_interrupt, > + "riscv-timer", &riscv_clock_event); > + if (error) { > + pr_err("registering percpu irq failed [%d]\n", error); > + return error; > + } > + > error = cpuhp_setup_state(CPUHP_AP_RISCV_TIMER_STARTING, > "clockevents/riscv/timer:starting", > riscv_timer_starting_cpu, riscv_timer_dying_cpu); > diff --git a/drivers/irqchip/irq-riscv-intc.c > b/drivers/irqchip/irq-riscv-intc.c > index 2f364e6a87f9..d4fbc3543459 100644 > --- a/drivers/irqchip/irq-riscv-intc.c > +++ b/drivers/irqchip/irq-riscv-intc.c > @@ -23,20 +23,12 @@ static struct irq_domain *intc_domain; > > static asmlinkage void riscv_intc_irq(struct pt_regs *regs) > { > - struct pt_regs *old_regs; > unsigned long cause = regs->cause & ~CAUSE_IRQ_FLAG; > > if (unlikely(cause >= BITS_PER_LONG)) > panic("unexpected interrupt cause"); > > switch (cause) { > - case RV_IRQ_TIMER: > - old_regs = set_irq_regs(regs); > - irq_enter(); > - riscv_timer_interrupt(); > - irq_exit(); > - set_irq_regs(old_regs); > - break; > #ifdef CONFIG_SMP > case RV_IRQ_SOFT: > /* > -- > 2.25.1 > > Otherwise, LGTM. Reviewed-by: Atish Patra <atish.pa...@wdc.com> -- Regards, Atish