| Date | Thu, 27 Aug 2020 09:17:13 +0100 | From | Marc Zyngier <> | Subject | Re: [patch V2 43/46] genirq/msi: Provide and use msi_domain_set_default_info_flags() |
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On 2020-08-26 12:17, Thomas Gleixner wrote: > MSI interrupts have some common flags which should be set not only for > PCI/MSI interrupts. > > Move the PCI/MSI flag setting into a common function so it can be > reused. > > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > --- > V2: New patch > --- > drivers/pci/msi.c | 7 +------ > include/linux/msi.h | 1 + > kernel/irq/msi.c | 24 ++++++++++++++++++++++++ > 3 files changed, 26 insertions(+), 6 deletions(-) > > --- a/drivers/pci/msi.c > +++ b/drivers/pci/msi.c > @@ -1469,12 +1469,7 @@ struct irq_domain *pci_msi_create_irq_do > if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS) > pci_msi_domain_update_chip_ops(info); > > - info->flags |= MSI_FLAG_ACTIVATE_EARLY; > - if (IS_ENABLED(CONFIG_GENERIC_IRQ_RESERVATION_MODE)) > - info->flags |= MSI_FLAG_MUST_REACTIVATE; > - > - /* PCI-MSI is oneshot-safe */ > - info->chip->flags |= IRQCHIP_ONESHOT_SAFE; > + msi_domain_set_default_info_flags(info); > > domain = msi_create_irq_domain(fwnode, info, parent); > if (!domain) > --- a/include/linux/msi.h > +++ b/include/linux/msi.h > @@ -410,6 +410,7 @@ int platform_msi_domain_alloc(struct irq > void platform_msi_domain_free(struct irq_domain *domain, unsigned int > virq, > unsigned int nvec); > void *platform_msi_get_host_data(struct irq_domain *domain); > +void msi_domain_set_default_info_flags(struct msi_domain_info *info); > #endif /* CONFIG_GENERIC_MSI_IRQ_DOMAIN */ > > #ifdef CONFIG_PCI_MSI_IRQ_DOMAIN > --- a/kernel/irq/msi.c > +++ b/kernel/irq/msi.c > @@ -70,6 +70,30 @@ void get_cached_msi_msg(unsigned int irq > EXPORT_SYMBOL_GPL(get_cached_msi_msg); > > #ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN > +void msi_domain_set_default_info_flags(struct msi_domain_info *info) > +{ > + /* Required so that a device latches a valid MSI message on startup > */ > + info->flags |= MSI_FLAG_ACTIVATE_EARLY;
As far as I remember the story behind this flag (it's been a while), it was working around a PCI-specific issue, hence being located in the PCI code.
Now, the "program the MSI before enabling it" concept makes sense no matter what bus this is on, and I wonder why we are even keeping this flag around. Can't we just drop it together with the check in msi_domain_alloc_irqs()?
Thanks,
M. -- Jazz is not dead. It just smells funny...
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