Linux generic IRQ handling

Table of Contents

1. Introduction

2. Rationale

3. Known Bugs And Assumptions

4. Abstraction layers

Interrupt control flow

High-level Driver API

High-level IRQ flow handlers

Default flow implementations

Default flow handler implementations

Quirks and optimizations

Delayed interrupt disable

Chip-level hardware encapsulation

5. __do_IRQ entry point

6. Locking on SMP

7. Generic interrupt chip

irq_gc_mask_set_bit — Mask chip via setting bit in mask register

irq_gc_mask_clr_bit — Mask chip via clearing bit in mask register

irq_gc_ack_set_bit — Ack pending interrupt via setting bit

irq_alloc_generic_chip — Allocate a generic chip and initialize it

__irq_alloc_domain_generic_chips — Allocate generic chips for an irq domain

irq_get_domain_generic_chip — Get a pointer to the generic chip of a hw_irq

irq_setup_generic_chip — Setup a range of interrupts with a generic chip

irq_setup_alt_chip — Switch to alternative chip

irq_remove_generic_chip — Remove a chip

8. Structures

struct irq_common_data — per irq data shared by all irqchips

struct irq_data — per irq chip data passed down to chip functions

struct irq_chip — hardware interrupt chip descriptor

struct irq_chip_regs — register offsets for struct irq_gci

struct irq_chip_type — Generic interrupt chip instance for a flow type

struct irq_chip_generic — Generic irq chip data structure

enum irq_gc_flags — Initialization flags for generic irq chips

struct irqaction — per interrupt action descriptor

struct irq_affinity_notify — context for notification of IRQ affinity changes

struct irq_affinity — Description for automatic irq affinity assignements

irq_set_affinity — Set the irq affinity of a given irq

irq_force_affinity — Force the irq affinity of a given irq

9. Public Functions Provided

synchronize_hardirq — wait for pending hard IRQ handlers (on other CPUs)

synchronize_irq — wait for pending IRQ handlers (on other CPUs)

irq_set_affinity_notifier — control notification of IRQ affinity changes

irq_set_vcpu_affinity — Set vcpu affinity for the interrupt

disable_irq_nosync — disable an irq without waiting

disable_irq — disable an irq and wait for completion

disable_hardirq — disables an irq and waits for hardirq completion

enable_irq — enable handling of an irq

irq_set_irq_wake — control irq power management wakeup

irq_wake_thread — wake the irq thread for the action identified by dev_id

setup_irq — setup an interrupt

remove_irq — free an interrupt

free_irq — free an interrupt allocated with request_irq

request_threaded_irq — allocate an interrupt line

request_any_context_irq — allocate an interrupt line

irq_percpu_is_enabled — Check whether the per cpu irq is enabled

free_percpu_irq — free an interrupt allocated with request_percpu_irq

request_percpu_irq — allocate a percpu interrupt line

irq_get_irqchip_state — returns the irqchip state of a interrupt.

irq_set_irqchip_state — set the state of a forwarded interrupt.

irq_set_chip — set the irq chip for an irq

irq_set_irq_type — set the irq trigger type for an irq

irq_set_handler_data — set irq handler data for an irq

irq_set_chip_data — set irq chip data for an irq

handle_simple_irq — Simple and software-decoded IRQs.

handle_untracked_irq — Simple and software-decoded IRQs.

handle_level_irq — Level type irq handler

handle_fasteoi_irq — irq handler for transparent controllers

handle_edge_irq — edge type IRQ handler

irq_chip_ack_parent — Acknowledge the parent interrupt

irq_chip_mask_parent — Mask the parent interrupt

irq_chip_unmask_parent — Unmask the parent interrupt

irq_chip_eoi_parent — Invoke EOI on the parent interrupt

irq_chip_set_type_parent — Set IRQ type on the parent interrupt

10. Internal Functions Provided

__handle_domain_irq — Invoke the handler for a HW irq belonging to a domain

irq_get_next_irq — get next allocated irq number

kstat_irqs_cpu — Get the statistics for an interrupt on a cpu

kstat_irqs — Get the statistics for an interrupt

kstat_irqs_usr — Get the statistics for an interrupt

kernel/irq/handle.c — Document generation inconsistency

irq_set_msi_desc_off — set MSI descriptor data for an irq at offset

irq_set_msi_desc — set MSI descriptor data for an irq

irq_disable — Mark interrupt disabled

handle_edge_eoi_irq — edge eoi type IRQ handler

handle_percpu_irq — Per CPU local irq handler

handle_percpu_devid_irq — Per CPU local irq handler with per cpu dev ids

irq_cpu_online — Invoke all irq_cpu_online functions.

irq_cpu_offline — Invoke all irq_cpu_offline functions.

irq_chip_enable_parent — Enable the parent interrupt (defaults to unmask if NULL)

irq_chip_disable_parent — Disable the parent interrupt (defaults to mask if NULL)

irq_chip_set_affinity_parent — Set affinity on the parent interrupt

irq_chip_retrigger_hierarchy — Retrigger an interrupt in hardware

irq_chip_set_vcpu_affinity_parent — Set vcpu affinity on the parent interrupt

irq_chip_set_wake_parent — Set/reset wake-up on the parent interrupt

irq_chip_compose_msi_msg — Componse msi message for a irq chip

irq_chip_pm_get — Enable power for an IRQ chip

irq_chip_pm_put — Disable power for an IRQ chip

11. Credits