/*
   * System Trace Module (STM) infrastructure apis
   * Copyright (C) 2014 Intel Corporation.
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms and conditions of the GNU General Public License,
   * version 2, as published by the Free Software Foundation.
   *
   * This program is distributed in the hope it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
   * more details.
   */
  
  #ifndef _STM_H_
  #define _STM_H_
  
  #include <linux/device.h>
  
  /**
   * enum stp_packet_type - STP packets that an STM driver sends
   */
  enum stp_packet_type {
  	STP_PACKET_DATA = 0,
  	STP_PACKET_FLAG,
  	STP_PACKET_USER,
  	STP_PACKET_MERR,
  	STP_PACKET_GERR,
  	STP_PACKET_TRIG,
  	STP_PACKET_XSYNC,
  };
  
  /**
   * enum stp_packet_flags - STP packet modifiers
   */
  enum stp_packet_flags {
  	STP_PACKET_MARKED	= 0x1,
  	STP_PACKET_TIMESTAMPED	= 0x2,
  };
  
  struct stp_policy;
  
  struct stm_device;
  
  /**
   * struct stm_data - STM device description and callbacks
   * @name:		device name
   * @stm:		internal structure, only used by stm class code
   * @sw_start:		first STP master available to software
   * @sw_end:		last STP master available to software
   * @sw_nchannels:	number of STP channels per master
   * @sw_mmiosz:		size of one channel's IO space, for mmap, optional

   * @hw_override:	masters in the STP stream will not match the ones
   *			assigned by software, but are up to the STM hardware

   * @packet:		callback that sends an STP packet
   * @mmio_addr:		mmap callback, optional
   * @link:		called when a new stm_source gets linked to us, optional
   * @unlink:		likewise for unlinking, again optional
   * @set_options:	set device-specific options on a channel
   *
   * Fill out this structure before calling stm_register_device() to create
   * an STM device and stm_unregister_device() to destroy it. It will also be
   * passed back to @packet(), @mmio_addr(), @link(), @unlink() and @set_options()
   * callbacks.
   *
   * Normally, an STM device will have a range of masters available to software
   * and the rest being statically assigned to various hardware trace sources.
   * The former is defined by the the range [@sw_start..@sw_end] of the device
   * description. That is, the lowest master that can be allocated to software
   * writers is @sw_start and data from this writer will appear is @sw_start
   * master in the STP stream.

   *
   * The @packet callback should adhere to the following rules:
   *   1) it must return the number of bytes it consumed from the payload;
   *   2) therefore, if it sent a packet that does not have payload (like FLAG),
   *      it must return zero;
   *   3) if it does not support the requested packet type/flag combination,
   *      it must return -ENOTSUPP.

   *
   * The @unlink callback is called when there are no more active writers so
   * that the master/channel can be quiesced.

   */
  struct stm_data {
  	const char		*name;
  	struct stm_device	*stm;
  	unsigned int		sw_start;
  	unsigned int		sw_end;
  	unsigned int		sw_nchannels;
  	unsigned int		sw_mmiosz;

  	unsigned int		hw_override;

  	ssize_t			(*packet)(struct stm_data *, unsigned int,
  					  unsigned int, unsigned int,
  					  unsigned int, unsigned int,
  					  const unsigned char *);
  	phys_addr_t		(*mmio_addr)(struct stm_data *, unsigned int,
  					     unsigned int, unsigned int);
  	int			(*link)(struct stm_data *, unsigned int,
  					unsigned int);
  	void			(*unlink)(struct stm_data *, unsigned int,
  					  unsigned int);
  	long			(*set_options)(struct stm_data *, unsigned int,
  					       unsigned int, unsigned int,
  					       unsigned long);
  };
  
  int stm_register_device(struct device *parent, struct stm_data *stm_data,
  			struct module *owner);
  void stm_unregister_device(struct stm_data *stm_data);
  
  struct stm_source_device;
  
  /**
   * struct stm_source_data - STM source device description and callbacks
   * @name:	device name, will be used for policy lookup
   * @src:	internal structure, only used by stm class code
   * @nr_chans:	number of channels to allocate
   * @link:	called when this source gets linked to an STM device
   * @unlink:	called when this source is about to get unlinked from its STM
   *
   * Fill in this structure before calling stm_source_register_device() to
   * register a source device. Also pass it to unregister and write calls.
   */
  struct stm_source_data {
  	const char		*name;
  	struct stm_source_device *src;
  	unsigned int		percpu;
  	unsigned int		nr_chans;
  	int			(*link)(struct stm_source_data *data);
  	void			(*unlink)(struct stm_source_data *data);
  };
  
  int stm_source_register_device(struct device *parent,
  			       struct stm_source_data *data);
  void stm_source_unregister_device(struct stm_source_data *data);

  int notrace stm_source_write(struct stm_source_data *data, unsigned int chan,
  			     const char *buf, size_t count);

  
  #endif /* _STM_H_ */