LXR linux/include/linux/irqbypass.h

   1/* SPDX-License-Identifier: GPL-2.0-only */
   2/*
   3 * IRQ offload/bypass manager
   4 *
   5 * Copyright (C) 2015 Red Hat, Inc.
   6 * Copyright (c) 2015 Linaro Ltd.
   7 */
   8#ifndef IRQBYPASS_H
   9#define IRQBYPASS_H
  10
  11#include <linux/list.h>
  12
  13struct irq_bypass_consumer;
  14
  15/*
  16 * Theory of operation
  17 *
  18 * The IRQ bypass manager is a simple set of lists and callbacks that allows
  19 * IRQ producers (ex. physical interrupt sources) to be matched to IRQ
  20 * consumers (ex. virtualization hardware that allows IRQ bypass or offload)
  21 * via a shared token (ex. eventfd_ctx).  Producers and consumers register
  22 * independently.  When a token match is found, the optional @stop callback
  23 * will be called for each participant.  The pair will then be connected via
  24 * the @add_* callbacks, and finally the optional @start callback will allow
  25 * any final coordination.  When either participant is unregistered, the
  26 * process is repeated using the @del_* callbacks in place of the @add_*
  27 * callbacks.  Match tokens must be unique per producer/consumer, 1:N pairings
  28 * are not supported.
  29 */
  30
  31/**
  32 * struct irq_bypass_producer - IRQ bypass producer definition
  33 * @node: IRQ bypass manager private list management
  34 * @token: opaque token to match between producer and consumer (non-NULL)
  35 * @irq: Linux IRQ number for the producer device
  36 * @add_consumer: Connect the IRQ producer to an IRQ consumer (optional)
  37 * @del_consumer: Disconnect the IRQ producer from an IRQ consumer (optional)
  38 * @stop: Perform any quiesce operations necessary prior to add/del (optional)
  39 * @start: Perform any startup operations necessary after add/del (optional)
  40 *
  41 * The IRQ bypass producer structure represents an interrupt source for
  42 * participation in possible host bypass, for instance an interrupt vector
  43 * for a physical device assigned to a VM.
  44 */
  45struct irq_bypass_producer {
  46        struct list_head node;
  47        void *token;
  48        int irq;
  49        int (*add_consumer)(struct irq_bypass_producer *,
  50                            struct irq_bypass_consumer *);
  51        void (*del_consumer)(struct irq_bypass_producer *,
  52                             struct irq_bypass_consumer *);
  53        void (*stop)(struct irq_bypass_producer *);
  54        void (*start)(struct irq_bypass_producer *);
  55};
  56
  57/**
  58 * struct irq_bypass_consumer - IRQ bypass consumer definition
  59 * @node: IRQ bypass manager private list management
  60 * @token: opaque token to match between producer and consumer (non-NULL)
  61 * @add_producer: Connect the IRQ consumer to an IRQ producer
  62 * @del_producer: Disconnect the IRQ consumer from an IRQ producer
  63 * @stop: Perform any quiesce operations necessary prior to add/del (optional)
  64 * @start: Perform any startup operations necessary after add/del (optional)
  65 *
  66 * The IRQ bypass consumer structure represents an interrupt sink for
  67 * participation in possible host bypass, for instance a hypervisor may
  68 * support offloads to allow bypassing the host entirely or offload
  69 * portions of the interrupt handling to the VM.
  70 */
  71struct irq_bypass_consumer {
  72        struct list_head node;
  73        void *token;
  74        int (*add_producer)(struct irq_bypass_consumer *,
  75                            struct irq_bypass_producer *);
  76        void (*del_producer)(struct irq_bypass_consumer *,
  77                             struct irq_bypass_producer *);
  78        void (*stop)(struct irq_bypass_consumer *);
  79        void (*start)(struct irq_bypass_consumer *);
  80};
  81
  82int irq_bypass_register_producer(struct irq_bypass_producer *);
  83void irq_bypass_unregister_producer(struct irq_bypass_producer *);
  84int irq_bypass_register_consumer(struct irq_bypass_consumer *);
  85void irq_bypass_unregister_consumer(struct irq_bypass_consumer *);
  86
  87#endif /* IRQBYPASS_H */
  88