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authorYun Wu <wuyun.wu@huawei.com>2015-03-06 19:37:50 +0300
committerJason Cooper <jason@lakedaemon.net>2015-03-08 08:34:58 +0300
commit4559fbb3a9b1bde46afc739fa6c300826acdc19c (patch)
treeb2d257b5b9de9e1f5c70bfa76566aeff5ce2320b /drivers/irqchip
parent7cb991164a46992a499ecdc77b17f8ac94bdb75f (diff)
downloadlinux-4559fbb3a9b1bde46afc739fa6c300826acdc19c.tar.xz
irqchip: gicv3-its: Support safe initialization
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 <marc.zyngier@arm.com> Signed-off-by: Yun Wu <wuyun.wu@huawei.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Link: https://lkml.kernel.org/r/1425659870-11832-12-git-send-email-marc.zyngier@arm.com Signed-off-by: Jason Cooper <jason@lakedaemon.net>
Diffstat (limited to 'drivers/irqchip')
-rw-r--r--drivers/irqchip/irq-gic-v3-its.c35
1 files changed, 35 insertions, 0 deletions
diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 826da706be4b..596b0a9eee99 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);