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From: Paul Burton <paul.burton@imgtec.com>
To: Thomas Gleixner <tglx@linutronix.de>, Ralf Baechle <ralf@linux-mips.org>
Cc: <dianders@chromium.org>, James Hogan <james.hogan@imgtec.com>,
	Brian Norris <briannorris@chromium.org>,
	Jason Cooper <jason@lakedaemon.net>, <jeffy.chen@rock-chips.com>,
	Marc Zyngier <marc.zyngier@arm.com>,
	<linux-kernel@vger.kernel.org>, <linux-mips@linux-mips.org>,
	<tfiga@chromium.org>, Paul Burton <paul.burton@imgtec.com>
Subject: [RFC PATCH v1 7/9] MIPS: cevt-r4k: percpu_devid interrupt support
Date: Thu, 7 Sep 2017 16:25:40 -0700
Message-ID: <20170907232542.20589-8-paul.burton@imgtec.com> (raw)
In-Reply-To: <20170907232542.20589-1-paul.burton@imgtec.com>

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 <paul.burton@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
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

  parent reply index

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1682867.tATABVWsV9@np-p-burton>
2017-09-07 23:25 ` [RFC PATCH v1 0/9] Support shared percpu interrupts; clean up MIPS hacks Paul Burton
2017-09-07 23:25   ` [RFC PATCH v1 1/9] genirq: Allow shared interrupt users to opt into IRQ_NOAUTOEN Paul Burton
2017-09-07 23:25   ` [RFC PATCH v1 2/9] genirq: Support shared per_cpu_devid interrupts Paul Burton
2017-09-25 21:06     ` Thomas Gleixner
2017-09-26 12:00       ` Thomas Gleixner
2017-10-19 14:08         ` Thomas Gleixner
2017-09-07 23:25   ` [RFC PATCH v1 3/9] genirq: Introduce irq_is_percpu_devid() Paul Burton
2017-09-07 23:25   ` [RFC PATCH v1 4/9] MIPS: Remove perf_irq interrupt sharing fallback Paul Burton
2017-09-07 23:25   ` [RFC PATCH v1 5/9] MIPS: Remove perf_irq Paul Burton
2017-09-07 23:25   ` [RFC PATCH v1 6/9] MIPS: perf: percpu_devid interrupt support Paul Burton
2017-10-19 14:12     ` Thomas Gleixner
2017-09-07 23:25   ` Paul Burton [this message]
2017-09-07 23:25   ` [RFC PATCH v1 8/9] irqchip: mips-cpu: Set timer, FDC & perf interrupts percpu_devid Paul Burton
2017-09-07 23:25   ` [RFC PATCH v1 9/9] irqchip: mips-gic: Remove gic_all_vpes_local_irq_controller Paul Burton

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