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>
Reviewed-by: Atish Patra <atish.pa...@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;
+ }
+ if (!domain) {
+ pr_err("Failed to find interrupt 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 +153,14 @@ 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 84e7bda3a090..e6c07d8f3893 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:
/*
--
2.25.1
