Commit 033a65de authored by Anup Patel's avatar Anup Patel Committed by Palmer Dabbelt

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: default avatarAnup Patel <anup.patel@wdc.com>
Reviewed-by: default avatarAtish Patra <atish.patra@wdc.com>
Reviewed-by: default avatarMarc Zyngier <maz@kernel.org>
Signed-off-by: default avatarPalmer Dabbelt <palmerdabbelt@google.com>
parent 6b7ce892
......@@ -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 */
......@@ -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 +125,25 @@ 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);
......
......@@ -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:
/*
......
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