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
  16 struct 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  */
  48 struct 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  */
  74 struct 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
  85 int irq_bypass_register_producer(struct irq_bypass_producer *);
  86 void irq_bypass_unregister_producer(struct irq_bypass_producer *);
  87 int irq_bypass_register_consumer(struct irq_bypass_consumer *);
  88 void irq_bypass_unregister_consumer(struct irq_bypass_consumer *);
  89
  90 #endif /* IRQBYPASS_H */