From: Yun Wu <wuyun.wu@huawei.com>
To: <marc.zyngier@arm.com>, <tglx@linutronix.de>, <jason@lakedaemon.net>
Cc: <linux-kernel@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
Yun Wu <wuyun.wu@huawei.com>
Subject: [PATCH v2 5/6] irqchip: gicv3-its: add support for power down
Date: Sun, 15 Feb 2015 17:32:02 +0800 [thread overview]
Message-ID: <1423992723-5028-6-git-send-email-wuyun.wu@huawei.com> (raw)
In-Reply-To: <1423992723-5028-1-git-send-email-wuyun.wu@huawei.com>
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 <wuyun.wu@huawei.com>
---
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
next prev parent reply other threads:[~2015-02-15 9:34 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-15 9:31 [PATCH v2 0/6] enhance configuring an ITS Yun Wu
2015-02-15 9:31 ` [PATCH v2 1/6] irqchip: gicv3-its: zero itt before handling to hardware Yun Wu
2015-02-15 9:31 ` [PATCH v2 2/6] irqchip: gicv3-its: use 64KB page as default granule Yun Wu
2015-02-17 9:46 ` Marc Zyngier
2015-02-15 9:32 ` [PATCH v2 3/6] irqchip: gicv3-its: limit order of DT size to MAX_ORDER Yun Wu
2015-02-17 9:19 ` Marc Zyngier
2015-02-17 10:00 ` Yun Wu (Abel)
2015-02-15 9:32 ` [PATCH v2 4/6] irqchip: gicv3-its: define macros for GITS_CTLR fields Yun Wu
2015-02-15 9:32 ` Yun Wu [this message]
2015-02-17 9:29 ` [PATCH v2 5/6] irqchip: gicv3-its: add support for power down Marc Zyngier
2015-02-17 10:15 ` Yun Wu (Abel)
2015-02-17 11:11 ` Marc Zyngier
2015-02-17 12:27 ` Yun Wu (Abel)
2015-03-04 3:10 ` Yun Wu (Abel)
2015-02-15 9:32 ` [PATCH v2 6/6] irqchip: gicv3: skip ITS init when no ITS available Yun Wu
2015-02-16 10:05 ` Vladimir Murzin
2015-02-16 14:57 ` Yun Wu (Abel)
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