LXR linux/include/linux/stm.h

   1/*
   2 * System Trace Module (STM) infrastructure apis
   3 * Copyright (C) 2014 Intel Corporation.
   4 *
   5 * This program is free software; you can redistribute it and/or modify it
   6 * under the terms and conditions of the GNU General Public License,
   7 * version 2, as published by the Free Software Foundation.
   8 *
   9 * This program is distributed in the hope it will be useful, but WITHOUT
  10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12 * more details.
  13 */
  14
  15#ifndef _STM_H_
  16#define _STM_H_
  17
  18#include <linux/device.h>
  19
  20/**
  21 * enum stp_packet_type - STP packets that an STM driver sends
  22 */
  23enum stp_packet_type {
  24        STP_PACKET_DATA = 0,
  25        STP_PACKET_FLAG,
  26        STP_PACKET_USER,
  27        STP_PACKET_MERR,
  28        STP_PACKET_GERR,
  29        STP_PACKET_TRIG,
  30        STP_PACKET_XSYNC,
  31};
  32
  33/**
  34 * enum stp_packet_flags - STP packet modifiers
  35 */
  36enum stp_packet_flags {
  37        STP_PACKET_MARKED       = 0x1,
  38        STP_PACKET_TIMESTAMPED  = 0x2,
  39};
  40
  41struct stp_policy;
  42
  43struct stm_device;
  44
  45/**
  46 * struct stm_data - STM device description and callbacks
  47 * @name:               device name
  48 * @stm:                internal structure, only used by stm class code
  49 * @sw_start:           first STP master available to software
  50 * @sw_end:             last STP master available to software
  51 * @sw_nchannels:       number of STP channels per master
  52 * @sw_mmiosz:          size of one channel's IO space, for mmap, optional
  53 * @packet:             callback that sends an STP packet
  54 * @mmio_addr:          mmap callback, optional
  55 * @link:               called when a new stm_source gets linked to us, optional
  56 * @unlink:             likewise for unlinking, again optional
  57 * @set_options:        set device-specific options on a channel
  58 *
  59 * Fill out this structure before calling stm_register_device() to create
  60 * an STM device and stm_unregister_device() to destroy it. It will also be
  61 * passed back to @packet(), @mmio_addr(), @link(), @unlink() and @set_options()
  62 * callbacks.
  63 *
  64 * Normally, an STM device will have a range of masters available to software
  65 * and the rest being statically assigned to various hardware trace sources.
  66 * The former is defined by the the range [@sw_start..@sw_end] of the device
  67 * description. That is, the lowest master that can be allocated to software
  68 * writers is @sw_start and data from this writer will appear is @sw_start
  69 * master in the STP stream.
  70 *
  71 * The @packet callback should adhere to the following rules:
  72 *   1) it must return the number of bytes it consumed from the payload;
  73 *   2) therefore, if it sent a packet that does not have payload (like FLAG),
  74 *      it must return zero;
  75 *   3) if it does not support the requested packet type/flag combination,
  76 *      it must return -ENOTSUPP.
  77 *
  78 * The @unlink callback is called when there are no more active writers so
  79 * that the master/channel can be quiesced.
  80 */
  81struct stm_data {
  82        const char              *name;
  83        struct stm_device       *stm;
  84        unsigned int            sw_start;
  85        unsigned int            sw_end;
  86        unsigned int            sw_nchannels;
  87        unsigned int            sw_mmiosz;
  88        ssize_t                 (*packet)(struct stm_data *, unsigned int,
  89                                          unsigned int, unsigned int,
  90                                          unsigned int, unsigned int,
  91                                          const unsigned char *);
  92        phys_addr_t             (*mmio_addr)(struct stm_data *, unsigned int,
  93                                             unsigned int, unsigned int);
  94        int                     (*link)(struct stm_data *, unsigned int,
  95                                        unsigned int);
  96        void                    (*unlink)(struct stm_data *, unsigned int,
  97                                          unsigned int);
  98        long                    (*set_options)(struct stm_data *, unsigned int,
  99                                               unsigned int, unsigned int,
 100                                               unsigned long);
 101};
 102
 103int stm_register_device(struct device *parent, struct stm_data *stm_data,
 104                        struct module *owner);
 105void stm_unregister_device(struct stm_data *stm_data);
 106
 107struct stm_source_device;
 108
 109/**
 110 * struct stm_source_data - STM source device description and callbacks
 111 * @name:       device name, will be used for policy lookup
 112 * @src:        internal structure, only used by stm class code
 113 * @nr_chans:   number of channels to allocate
 114 * @link:       called when this source gets linked to an STM device
 115 * @unlink:     called when this source is about to get unlinked from its STM
 116 *
 117 * Fill in this structure before calling stm_source_register_device() to
 118 * register a source device. Also pass it to unregister and write calls.
 119 */
 120struct stm_source_data {
 121        const char              *name;
 122        struct stm_source_device *src;
 123        unsigned int            percpu;
 124        unsigned int            nr_chans;
 125        int                     (*link)(struct stm_source_data *data);
 126        void                    (*unlink)(struct stm_source_data *data);
 127};
 128
 129int stm_source_register_device(struct device *parent,
 130                               struct stm_source_data *data);
 131void stm_source_unregister_device(struct stm_source_data *data);
 132
 133int stm_source_write(struct stm_source_data *data, unsigned int chan,
 134                     const char *buf, size_t count);
 135
 136#endif /* _STM_H_ */
 137