[RFC Part4 v1 00/17] Refine support of non-PCI-compliant Message
From: Thomas Gleixner <hidden>
Date: 2014-11-13 13:28:30
Also in:
linux-acpi, linux-pci, lkml
On Thu, 13 Nov 2014, Marc Zyngier wrote:
On 12/11/14 14:46, Thomas Gleixner wrote:quoted
On Wed, 12 Nov 2014, Marc Zyngier wrote:quoted
This patch introduces two optionnal fields to the msi_chip structure: - a pointer to an irq domain, describing the MSI domain associated with this msi_chip. To be populated with msi_create_irq_domain. - a domain_alloc_irqs() callback that has the same purpose as arch_setup_msi_irqs(), with the above domain as an additional parameter. If both of these fields are non-NULL, then domain_alloc_irqs() is called, bypassing the setup_irq callback. This allows the MSI driver to use the domain stacking feature without mandating core support in the architecture.I'd rather have the callback in the irqdomain itself. Along with a callback to free the interrupts. AFAICT is msi_chip more or less a wrapper around the actual MSI irq domain. So we rather move towards assigning irqdomain to the pci bus and get rid of msi_chip instead of adding another level of obscure indirection through msi_chip.I can see that putting the irq domain at the bus level makes a lot of sense (assuming nobody tries to have multiple MSI controllers per bus...).
That would be interesting :)
quoted hunk ↗ jump to hunk
So I'm starting with something like this:diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h index 640a1ec..07e50fc 100644 --- a/include/linux/irqdomain.h +++ b/include/linux/irqdomain.h@@ -41,6 +41,7 @@ struct irq_domain; struct of_device_id; struct irq_chip; struct irq_data; +struct device; /* Number of irqs reserved for a legacy isa controller */ #define NUM_ISA_INTERRUPTS 16@@ -76,6 +77,10 @@ struct irq_domain_ops { unsigned int nr_irqs); void (*activate)(struct irq_domain *d, struct irq_data *irq_data); void (*deactivate)(struct irq_domain *d, struct irq_data *irq_data); + int (*prepare_alloc_irqs)(struct irq_domain *d, struct device *dev, + unsigned int nr_irqs, int type); + int (*cleanup_free_irqs)(struct irq_domain *d, struct device *dev, + unsigned int virq, unsigned int nr_irqs); #endif };How do you see this behaving? At the moment, I have the "prepare" callback directly calling into pci_msi_domain_alloc_irqs() so that the irqs get created, but I have the nagging feeling that it's not what you want... ;-) The main issue I can see is that if more than one domain in the stack implements that, who gets to call pci_msi_domain_alloc_irqs? If we try to decouple those two, there is a problem with the creation of the intermediate structure (the irq_alloc_info that's in Jiang's patches), as this is a arch/driver/whatever specific structure.
Hard to tell. I just saw Jiangs new series arrive and I want to look at that first before muttering nonsense. Thanks, tglx