Messages in this thread | | | Date | Thu, 05 Mar 2015 12:05:33 +0000 | From | Marc Zyngier <> | Subject | Re: [PATCH v3 5/5] irqchip: gicv3-its: support safe initialization |
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On 04/03/15 03:18, Yun Wu wrote: > 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. > > Signed-off-by: Yun Wu <wuyun.wu@huawei.com> > --- > 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_check_quiesced(void __iomem *base)
Another nitpick: Rather than "its_check_quiesced", how about "its_force_quiescent" instead? Because this does a lot more than just checking.
> +{ > + 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); > + } > +} > +
I still dislike this repeated pattern, but I don't have a good solution so far.
> 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_check_quiesced(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 > > >
Assuming you fix the above nitpick:
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
M. -- Jazz is not dead. It just smells funny...
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