Messages in this thread |  | | Date | Tue, 18 Nov 2014 11:02:12 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: [patch 04/16] genirq: Introduce irq_chip.irq_compose_msi_msg() to support stacked irqchip |
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On Tue, 18 Nov 2014, Yun Wu (Abel) wrote: > On 2014/11/12 21:42, Thomas Gleixner wrote: > > +int irq_chip_compose_msi_msg(struct irq_data *data, struct msi_msg *msg) > > +{ > > + struct irq_data *pos = NULL; > > + > > +#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY > > + for (; data; data = data->parent_data) > > +#endif > > + if (data->chip && data->chip->irq_compose_msi_msg) > > + pos = data; > > + if (!pos) > > + return -ENOSYS; > > + > > + pos->chip->irq_compose_msi_msg(pos, msg); > > + > > + return 0; > > +} > > Adding message composing routine to struct irq_chip is OK to me, and it should > be because it is interrupt controllers' duty to compose messages (so that they > can parse the messages correctly without any pre-defined rules that endpoint > devices absolutely need not to know). > However a problem comes out when deciding which parameters should be passed to > this routine. A message can associate with multiple interrupts, which makes me > think composing messages for each interrupt is not that appropriate. And we > can take a look at the new routine irq_chip_compose_msi_msg(). It is called by > msi_domain_activate() which will be called by irq_domain_activate_irq() in > irq_startup() for each interrupt descriptor, result in composing a message for > each interrupt, right? (Unless requiring a judge on the parameter @data when > implementing the irq_compose_msi_msg() callback that only compose message for > the first entry of that message. But I really don't like that...)
No, that's not correct. You are looking at some random stale version of this. The current state of affairs is in
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git irq/irqdomain
See also https://lkml.org/lkml/2014/11/17/764
In activate we write the message, which is the right point to do so.
Thanks,
tglx
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