linux-kernel - [PATCH 2/2] irqchip: mips-gic: Implement activate op for device domain

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Date:   Fri, 19 Aug 2016 18:07:15 +0100
From:   Paul Burton <paul.burton@...tec.com>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>,
        Marc Zyngier <marc.zyngier@....com>,
        <linux-kernel@...r.kernel.org>
CC:     <linux-mips@...ux-mips.org>, <stable@...r.kernel.org>,
        Paul Burton <paul.burton@...tec.com>
Subject: [PATCH 2/2] irqchip: mips-gic: Implement activate op for device domain

If an IRQ is setup using __setup_irq(), which is used by the
request_irq() family of functions, and we are using an SMP kernel then
the affinity of the IRQ will be set via setup_affinity() immediately
after the IRQ is enabled. This call to gic_set_affinity() will lead to
the interrupt being mapped to a VPE. However there are other ways to use
IRQs which don't cause affinity to be set, for example if it is used to
chain to another IRQ controller with irq_set_chained_handler_and_data().
The irq_set_chained_handler_and_data() code path will enable the IRQ,
but will not trigger a call to gic_set_affinity() and in this case
nothing will map the interrupt to a VPE, meaning that the interrupt is
never received.

Fix this by implementing the activate operation for the GIC device IRQ
domain, using gic_shared_irq_domain_map() to map the interrupt to the
correct pin of cpu 0.

Signed-off-by: Paul Burton <paul.burton@...tec.com>
Fixes: c98c1822ee13 ("irqchip/mips-gic: Add device hierarchy domain")
Cc: stable@...r.kernel.org # v4.6+
---
This one would be great to get in ASAP, for v4.8 if possible, as it breaks
certain uses of GIC interrupts.
---
 drivers/irqchip/irq-mips-gic.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/irqchip/irq-mips-gic.c b/drivers/irqchip/irq-mips-gic.c
index d7ec984..d3ef0fc 100644
--- a/drivers/irqchip/irq-mips-gic.c
+++ b/drivers/irqchip/irq-mips-gic.c
@@ -893,10 +893,17 @@ void gic_dev_domain_free(struct irq_domain *d, unsigned int virq,
 	return;
 }

+static void gic_dev_domain_activate(struct irq_domain *domain,
+				    struct irq_data *d)
+{
+	gic_shared_irq_domain_map(domain, d->irq, d->hwirq, 0);
+}
+
 static struct irq_domain_ops gic_dev_domain_ops = {
 	.xlate = gic_dev_domain_xlate,
 	.alloc = gic_dev_domain_alloc,
 	.free = gic_dev_domain_free,
+	.activate = gic_dev_domain_activate,
 };

 static int gic_ipi_domain_xlate(struct irq_domain *d, struct device_node *ctrlr,
-- 
2.9.3