LXR linux/include/linux/irqbypass.h

   1/*
   2 * IRQ offload/bypass manager
   3 *
   4 * Copyright (C) 2015 Red Hat, Inc.
   5 * Copyright (c) 2015 Linaro Ltd.
   6 *
   7 * This program is free software; you can redistribute it and/or modify
   8 * it under the terms of the GNU General Public License version 2 as
   9 * published by the Free Software Foundation.
  10 */
  11#ifndef IRQBYPASS_H
  12#define IRQBYPASS_H
  13
  14#include <linux/list.h>
  15
  16struct irq_bypass_consumer;
  17
  18/*
  19 * Theory of operation
  20 *
  21 * The IRQ bypass manager is a simple set of lists and callbacks that allows
  22 * IRQ producers (ex. physical interrupt sources) to be matched to IRQ
  23 * consumers (ex. virtualization hardware that allows IRQ bypass or offload)
  24 * via a shared token (ex. eventfd_ctx).  Producers and consumers register
  25 * independently.  When a token match is found, the optional @stop callback
  26 * will be called for each participant.  The pair will then be connected via
  27 * the @add_* callbacks, and finally the optional @start callback will allow
  28 * any final coordination.  When either participant is unregistered, the
  29 * process is repeated using the @del_* callbacks in place of the @add_*
  30 * callbacks.  Match tokens must be unique per producer/consumer, 1:N pairings
  31 * are not supported.
  32 */
  33
  34/**
  35 * struct irq_bypass_producer - IRQ bypass producer definition
  36 * @node: IRQ bypass manager private list management
  37 * @token: opaque token to match between producer and consumer (non-NULL)
  38 * @irq: Linux IRQ number for the producer device
  39 * @add_consumer: Connect the IRQ producer to an IRQ consumer (optional)
  40 * @del_consumer: Disconnect the IRQ producer from an IRQ consumer (optional)
  41 * @stop: Perform any quiesce operations necessary prior to add/del (optional)
  42 * @start: Perform any startup operations necessary after add/del (optional)
  43 *
  44 * The IRQ bypass producer structure represents an interrupt source for
  45 * participation in possible host bypass, for instance an interrupt vector
  46 * for a physical device assigned to a VM.
  47 */
  48struct irq_bypass_producer {
  49        struct list_head node;
  50        void *token;
  51        int irq;
  52        int (*add_consumer)(struct irq_bypass_producer *,
  53                            struct irq_bypass_consumer *);
  54        void (*del_consumer)(struct irq_bypass_producer *,
  55                             struct irq_bypass_consumer *);
  56        void (*stop)(struct irq_bypass_producer *);
  57        void (*start)(struct irq_bypass_producer *);
  58};
  59
  60/**
  61 * struct irq_bypass_consumer - IRQ bypass consumer definition
  62 * @node: IRQ bypass manager private list management
  63 * @token: opaque token to match between producer and consumer (non-NULL)
  64 * @add_producer: Connect the IRQ consumer to an IRQ producer
  65 * @del_producer: Disconnect the IRQ consumer from an IRQ producer
  66 * @stop: Perform any quiesce operations necessary prior to add/del (optional)
  67 * @start: Perform any startup operations necessary after add/del (optional)
  68 *
  69 * The IRQ bypass consumer structure represents an interrupt sink for
  70 * participation in possible host bypass, for instance a hypervisor may
  71 * support offloads to allow bypassing the host entirely or offload
  72 * portions of the interrupt handling to the VM.
  73 */
  74struct irq_bypass_consumer {
  75        struct list_head node;
  76        void *token;
  77        int (*add_producer)(struct irq_bypass_consumer *,
  78                            struct irq_bypass_producer *);
  79        void (*del_producer)(struct irq_bypass_consumer *,
  80                             struct irq_bypass_producer *);
  81        void (*stop)(struct irq_bypass_consumer *);
  82        void (*start)(struct irq_bypass_consumer *);
  83};
  84
  85int irq_bypass_register_producer(struct irq_bypass_producer *);
  86void irq_bypass_unregister_producer(struct irq_bypass_producer *);
  87int irq_bypass_register_consumer(struct irq_bypass_consumer *);
  88void irq_bypass_unregister_consumer(struct irq_bypass_consumer *);
  89
  90#endif /* IRQBYPASS_H */
  91