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kernel/linux-rt-4.4.41/include/linux/irqbypass.h 3.57 KB
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  /*
   * IRQ offload/bypass manager
   *
   * Copyright (C) 2015 Red Hat, Inc.
   * Copyright (c) 2015 Linaro Ltd.
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */
  #ifndef IRQBYPASS_H
  #define IRQBYPASS_H
  
  #include <linux/list.h>
  
  struct irq_bypass_consumer;
  
  /*
   * Theory of operation
   *
   * The IRQ bypass manager is a simple set of lists and callbacks that allows
   * IRQ producers (ex. physical interrupt sources) to be matched to IRQ
   * consumers (ex. virtualization hardware that allows IRQ bypass or offload)
   * via a shared token (ex. eventfd_ctx).  Producers and consumers register
   * independently.  When a token match is found, the optional @stop callback
   * will be called for each participant.  The pair will then be connected via
   * the @add_* callbacks, and finally the optional @start callback will allow
   * any final coordination.  When either participant is unregistered, the
   * process is repeated using the @del_* callbacks in place of the @add_*
   * callbacks.  Match tokens must be unique per producer/consumer, 1:N pairings
   * are not supported.
   */
  
  /**
   * struct irq_bypass_producer - IRQ bypass producer definition
   * @node: IRQ bypass manager private list management
   * @token: opaque token to match between producer and consumer
   * @irq: Linux IRQ number for the producer device
   * @add_consumer: Connect the IRQ producer to an IRQ consumer (optional)
   * @del_consumer: Disconnect the IRQ producer from an IRQ consumer (optional)
   * @stop: Perform any quiesce operations necessary prior to add/del (optional)
   * @start: Perform any startup operations necessary after add/del (optional)
   *
   * The IRQ bypass producer structure represents an interrupt source for
   * participation in possible host bypass, for instance an interrupt vector
   * for a physical device assigned to a VM.
   */
  struct irq_bypass_producer {
  	struct list_head node;
  	void *token;
  	int irq;
  	int (*add_consumer)(struct irq_bypass_producer *,
  			    struct irq_bypass_consumer *);
  	void (*del_consumer)(struct irq_bypass_producer *,
  			     struct irq_bypass_consumer *);
  	void (*stop)(struct irq_bypass_producer *);
  	void (*start)(struct irq_bypass_producer *);
  };
  
  /**
   * struct irq_bypass_consumer - IRQ bypass consumer definition
   * @node: IRQ bypass manager private list management
   * @token: opaque token to match between producer and consumer
   * @add_producer: Connect the IRQ consumer to an IRQ producer
   * @del_producer: Disconnect the IRQ consumer from an IRQ producer
   * @stop: Perform any quiesce operations necessary prior to add/del (optional)
   * @start: Perform any startup operations necessary after add/del (optional)
   *
   * The IRQ bypass consumer structure represents an interrupt sink for
   * participation in possible host bypass, for instance a hypervisor may
   * support offloads to allow bypassing the host entirely or offload
   * portions of the interrupt handling to the VM.
   */
  struct irq_bypass_consumer {
  	struct list_head node;
  	void *token;
  	int (*add_producer)(struct irq_bypass_consumer *,
  			    struct irq_bypass_producer *);
  	void (*del_producer)(struct irq_bypass_consumer *,
  			     struct irq_bypass_producer *);
  	void (*stop)(struct irq_bypass_consumer *);
  	void (*start)(struct irq_bypass_consumer *);
  };
  
  int irq_bypass_register_producer(struct irq_bypass_producer *);
  void irq_bypass_unregister_producer(struct irq_bypass_producer *);
  int irq_bypass_register_consumer(struct irq_bypass_consumer *);
  void irq_bypass_unregister_consumer(struct irq_bypass_consumer *);
  
  #endif /* IRQBYPASS_H */