[PATCH v2 5/6] irqchip: gicv3-its: add support for power down
From: Yun Wu <hidden>
Date: 2015-02-15 09:34:51
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 a safe quiescent status before initializing an ITS. Signed-off-by: Yun Wu <redacted> --- drivers/irqchip/irq-gic-v3-its.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+)
diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 42c03b2..29eb665 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c@@ -1321,6 +1321,31 @@ static const struct irq_domain_ops its_domain_ops = { .deactivate = its_irq_domain_deactivate, }; +static int its_check_quiesced(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 (count--) { + val = readl_relaxed(base + GITS_CTLR); + if (val & GITS_CTLR_QUIESCENT) + return 0; + cpu_relax(); + udelay(1); + } + + return -EBUSY; +} + static int its_probe(struct device_node *node, struct irq_domain *parent) { struct resource res;
@@ -1349,6 +1374,13 @@ static int its_probe(struct device_node *node, struct irq_domain *parent) goto out_unmap; } + err = its_check_quiesced(its_base); + if (err) { + pr_warn("%s: failed to quiesce, behaviour unpredictable\n", + node->full_name); + goto out_unmap; + } + pr_info("ITS: %s\n", node->full_name); its = kzalloc(sizeof(*its), GFP_KERNEL); --
1.8.0