[RFC PATCH v1 7/9] MIPS: cevt-r4k: percpu_devid interrupt support
From: Paul Burton <hidden>
Date: 2017-09-07 23:28:10
Also in:
lkml
Subsystem:
mips, the rest · Maintainers:
Thomas Bogendoerfer, Linus Torvalds
The MIPS coprocessor 0 count/compare interrupt, used by the cevt-r4k driver, is really a percpu interrupt but up until now we have not used the percpu interrupt APIs to configure & control it. In preparation for doing so, introduce support for percpu_devid interrupts in cevt-r4k. We switch from using request_irq() to using either setup_irq() or setup_percpu_irq() with an explicit struct irqaction such that we can set the flags, handler & name for that struct irqaction once rather than needing to duplicate them in calls to request_irq() and request_percpu_irq(). The IRQF_NOAUTOEN flag is passed because percpu interrupts automatically get IRQ_NOAUTOEN set by irq_set_percpu_devid_flags(). We opt into accepting this behaviour & explicitly enable the interrupt in r4k_clockevent_init() which is called on all CPUs during bringup. Signed-off-by: Paul Burton <redacted> Cc: James Hogan <redacted> Cc: Jason Cooper <redacted> Cc: Marc Zyngier <redacted> Cc: Ralf Baechle <redacted> Cc: Thomas Gleixner <redacted> Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org --- arch/mips/kernel/cevt-r4k.c | 29 ++++++++++++++++++++++------- 1 file changed, 22 insertions(+), 7 deletions(-)
diff --git a/arch/mips/kernel/cevt-r4k.c b/arch/mips/kernel/cevt-r4k.c
index 893aa32759d9..0021fc1226f3 100644
--- a/arch/mips/kernel/cevt-r4k.c
+++ b/arch/mips/kernel/cevt-r4k.c@@ -8,6 +8,7 @@ */ #include <linux/clockchips.h> #include <linux/interrupt.h> +#include <linux/once.h> #include <linux/percpu.h> #include <linux/smp.h> #include <linux/irq.h>
@@ -106,7 +107,6 @@ static unsigned int calculate_min_delta(void) } DEFINE_PER_CPU(struct clock_event_device, mips_clockevent_device); -int cp0_timer_irq_installed; irqreturn_t c0_compare_interrupt(int irq, void *dev_id) {
@@ -136,8 +136,9 @@ struct irqaction c0_compare_irqaction = { * IRQF_SHARED: The timer interrupt may be shared with other interrupts * such as perf counter and FDC interrupts. */ - .flags = IRQF_PERCPU | IRQF_TIMER | IRQF_SHARED, + .flags = IRQF_PERCPU | IRQF_TIMER | IRQF_SHARED | IRQF_NOAUTOEN, .name = "timer", + .percpu_dev_id = &mips_clockevent_device, };
@@ -222,11 +223,20 @@ unsigned int __weak get_c0_compare_int(void) return MIPS_CPU_IRQ_BASE + cp0_compare_irq; } +static void setup_c0_compare_int(int irq, int *err) +{ + if (irq_is_percpu_devid(irq)) + *err = setup_percpu_irq(irq, &c0_compare_irqaction); + else + *err = setup_irq(irq, &c0_compare_irqaction); +} + int r4k_clockevent_init(void) { unsigned int cpu = smp_processor_id(); struct clock_event_device *cd; unsigned int irq, min_delta; + int err; if (!cpu_has_counter || !mips_hpt_frequency) return -ENXIO;
@@ -258,12 +268,17 @@ int r4k_clockevent_init(void) clockevents_config_and_register(cd, mips_hpt_frequency, min_delta, 0x7fffffff); - if (cp0_timer_irq_installed) - return 0; - - cp0_timer_irq_installed = 1; + err = 0; + DO_ONCE(setup_c0_compare_int, irq, &err); + if (err) { + pr_err("Unable to setup timer IRQ %d: %d\n", irq, err); + return err; + } - setup_irq(irq, &c0_compare_irqaction); + if (irq_is_percpu_devid(irq)) + enable_percpu_irq(irq, IRQ_TYPE_NONE); + else + enable_irq(irq); return 0; }
--
2.14.1