On Fri, Apr 15, 2016 at 07:06:41PM +0200, Tomasz Nowicki wrote: > To enable PCI legacy IRQs on platforms booting with ACPI, arch code > should include ACPI specific callbacks that parse and set-up the > device IRQ number, equivalent to the DT boot path. Owing to the current > ACPI core scan handlers implementation, ACPI PCI legacy IRQs bindings > cannot be parsed at device add time, since that would trigger ACPI scan > handlers ordering issues depending on how the ACPI tables are defined. Can you be a little more specific about the issue here? I think you mean pci_device_add()-time, because that's where we call pcibios_add_device. Which ACPI tables are involved? _PRT? Why is that a problem? We don't cache those tables any more after 181380b702ee ("PCI/ACPI: Don't cache _PRT, and don't associate them with bus numbers"). x86 and ia64 both call acpi_pci_irq_enable() from pcibios_enable_device(). Could you do the same on ARM64? pcibios_enable_device() happens later than either pci_device_add() or pci_device_probe(). > To solve this problem and consolidate FW PCI legacy IRQs parsing in > one single pcibios callback (pending final removal), this patch moves > DT PCI IRQ parsing to the pcibios_alloc_irq() callback (called by > PCI core code at device probe time) and adds ACPI PCI legacy IRQs > parsing to the same callback too, so that FW PCI legacy IRQs parsing > is confined in one single arch callback that can be easily removed > when code parsing PCI legacy IRQs is consolidated and moved to core > PCI code. > > Signed-off-by: Tomasz Nowicki <tn@xxxxxxxxxxxx> > Suggested-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx> > --- > arch/arm64/kernel/pci.c | 11 ++++++++--- > 1 file changed, 8 insertions(+), 3 deletions(-) > > diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c > index c72de66..15109c11 100644 > --- a/arch/arm64/kernel/pci.c > +++ b/arch/arm64/kernel/pci.c > @@ -50,11 +50,16 @@ int pcibios_enable_device(struct pci_dev *dev, int mask) > } > > /* > - * Try to assign the IRQ number from DT when adding a new device > + * Try to assign the IRQ number when probing a new device > */ > -int pcibios_add_device(struct pci_dev *dev) > +int pcibios_alloc_irq(struct pci_dev *dev) > { > - dev->irq = of_irq_parse_and_map_pci(dev, 0, 0); > + if (acpi_disabled) > + dev->irq = of_irq_parse_and_map_pci(dev, 0, 0); > +#ifdef CONFIG_ACPI > + else > + return acpi_pci_irq_enable(dev); > +#endif Not your problem, but your patch makes it obvious: it's ugly that we set dev->irq to the IRQ returned from of_irq_parse_and_map_pci(), but acpi_pci_irq_enable() sets dev->irq internally. x86 also has the situation of calling either acpi_pci_irq_enable() or of_irq_parse_and_map_pci(), and it looks like they can even decide at run-time as you can here. If we're solving the same problem, can we use a similar mechanism? x86 sets a pcibios_enable_irq function pointer. > return 0; > } > -- > 1.9.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html