2017-10-18 10:58 GMT+02:00 Marc Zyngier <[email protected]>: > On 05/10/17 13:44, Bartosz Golaszewski wrote: >> Add a routine allowing to retrieve the offset corresponding with an >> allocated interrupt number from an irq_sim object. >> >> Signed-off-by: Bartosz Golaszewski <[email protected]> >> --- >> include/linux/irq_sim.h | 1 + >> kernel/irq/irq_sim.c | 15 +++++++++++++++ >> 2 files changed, 16 insertions(+) >> >> diff --git a/include/linux/irq_sim.h b/include/linux/irq_sim.h >> index 246f593face8..e9768ca81e3e 100644 >> --- a/include/linux/irq_sim.h >> +++ b/include/linux/irq_sim.h >> @@ -41,5 +41,6 @@ void irq_sim_fini(struct irq_sim *sim); >> void irq_sim_fire(struct irq_sim *sim, unsigned int offset); >> int irq_sim_irqnum(struct irq_sim *sim, unsigned int offset); >> int irq_sim_baseirq(struct irq_sim *sim); >> +unsigned int irq_sim_irq2offset(struct irq_sim *sim, int irq); >> >> #endif /* _LINUX_IRQ_SIM_H */ >> diff --git a/kernel/irq/irq_sim.c b/kernel/irq/irq_sim.c >> index 1be10d0e295f..9a9a1bc8853c 100644 >> --- a/kernel/irq/irq_sim.c >> +++ b/kernel/irq/irq_sim.c >> @@ -174,3 +174,18 @@ int irq_sim_baseirq(struct irq_sim *sim) >> return irq_sim_irqnum(sim, 0); >> } >> EXPORT_SYMBOL_GPL(irq_sim_baseirq); >> + >> +/** >> + * irq_sim_irq2offset - Get the offset of an allocated interrupt. >> + * >> + * @sim: The interrupt simulator object. >> + * irq: Allocated interrupt number. >> + * >> + * Perform a reverse lookup for the interrupt number and return its offset >> in >> + * the array allocated by sim_irq. >> + */ >> +unsigned int irq_sim_irq2offset(struct irq_sim *sim, int irq) >> +{ >> + return irq - sim->irq_base; >> +} >> +EXPORT_SYMBOL_GPL(irq_sim_irq2offset); >> > > How is that useful in a random driver? The irq base and the offset are > things that should be internal to an irqchip. Maybe you could explain > the context you want to use this in. >
The interrupts are allocated within the interrupt simulator code, but it's up to users to actually request these irqs. That's why we already have sim_irq_irqnum(). The IIO dummy driver (one of the users of irq_sim) uses these irq numbers retrieved from the simulator to also access private data stored in the iio_dummy_evgen module. Currently we store the base interrupt number in a separate variable in the dummy_evgen context struct and calculate the offset in the interrupt array manually. We could simplify that code by moving this logic into the interrupt simulator. I hope it's clear enough. Best regards, Bartosz Golaszewski
