From 033a65de7eced89f62d2cd166b1ee2d33af4f1e4 Mon Sep 17 00:00:00 2001 From: Anup Patel Date: Mon, 1 Jun 2020 14:45:41 +0530 Subject: [PATCH] clocksource/drivers/timer-riscv: Use per-CPU timer interrupt 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 Reviewed-by: Atish Patra Reviewed-by: Marc Zyngier Signed-off-by: Palmer Dabbelt --- arch/riscv/include/asm/irq.h | 2 -- drivers/clocksource/timer-riscv.c | 43 ++++++++++++++++++++++++++++--- drivers/irqchip/irq-riscv-intc.c | 8 ------ 3 files changed, 40 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 #include -void riscv_timer_interrupt(void); - #include #endif /* _ASM_RISCV_IRQ_H */ diff --git a/drivers/clocksource/timer-riscv.c b/drivers/clocksource/timer-riscv.c index c4f15c4068c0..9de1dabfb126 100644 --- a/drivers/clocksource/timer-riscv.c +++ b/drivers/clocksource/timer-riscv.c @@ -12,8 +12,11 @@ #include #include #include +#include #include #include +#include +#include #include #include @@ -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 +125,25 @@ static int __init riscv_timer_init_dt(struct device_node *n) if (cpuid != smp_processor_id()) return 0; + domain = NULL; + child = of_get_compatible_child(n, "riscv,cpu-intc"); + if (!child) { + pr_err("Failed to find INTC node [%pOF]\n", n); + return -ENODEV; + } + domain = irq_find_host(child); + of_node_put(child); + if (!domain) { + pr_err("Failed to find IRQ domain for node [%pOF]\n", n); + return -ENODEV; + } + + riscv_clock_event_irq = irq_create_mapping(domain, RV_IRQ_TIMER); + if (!riscv_clock_event_irq) { + pr_err("Failed to map timer interrupt for node [%pOF]\n", n); + return -ENODEV; + } + pr_info("%s: Registering clocksource cpuid [%d] hartid [%d]\n", __func__, cpuid, hartid); error = clocksource_register_hz(&riscv_clocksource, riscv_timebase); @@ -126,6 +155,14 @@ 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 a80fb1731c50..a6f97fa6ff69 100644 --- a/drivers/irqchip/irq-riscv-intc.c +++ b/drivers/irqchip/irq-riscv-intc.c @@ -21,20 +21,12 @@ 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: /*