[PATCH v4 5/5] irqchip: gicv3-its: support safe initialization
From: Yun Wu <hidden>
Date: 2015-03-06 04:14:45
Also in:
lkml
Subsystem:
arm generic interrupt controller drivers, irqchip drivers, the rest · Maintainers:
Marc Zyngier, Thomas Gleixner, Linus Torvalds
It's unsafe to change the configurations of an activated ITS directly since this will lead to unpredictable results. This patch guarantees the ITSes being initialized are quiescent. Acked-by: Marc Zyngier <redacted> Signed-off-by: Yun Wu <redacted> --- drivers/irqchip/irq-gic-v3-its.c | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+)
diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index d13c24e..9e09aa0 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c@@ -1320,6 +1320,34 @@ static const struct irq_domain_ops its_domain_ops = { .deactivate = its_irq_domain_deactivate, }; +static int its_force_quiescent(void __iomem *base) +{ + u32 count = 1000000; /* 1s */ + u32 val; + + val = readl_relaxed(base + GITS_CTLR); + if (val & GITS_CTLR_QUIESCENT) + return 0; + + /* Disable the generation of all interrupts to this ITS */ + val &= ~GITS_CTLR_ENABLE; + writel_relaxed(val, base + GITS_CTLR); + + /* Poll GITS_CTLR and wait until ITS becomes quiescent */ + while (1) { + val = readl_relaxed(base + GITS_CTLR); + if (val & GITS_CTLR_QUIESCENT) + return 0; + + count--; + if (!count) + return -EBUSY; + + cpu_relax(); + udelay(1); + } +} + static int its_probe(struct device_node *node, struct irq_domain *parent) { struct resource res;
@@ -1348,6 +1376,13 @@ static int its_probe(struct device_node *node, struct irq_domain *parent) goto out_unmap; } + err = its_force_quiescent(its_base); + if (err) { + pr_warn("%s: failed to quiesce, giving up\n", + node->full_name); + goto out_unmap; + } + pr_info("ITS: %s\n", node->full_name); its = kzalloc(sizeof(*its), GFP_KERNEL); --
1.8.0