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  */
  23 enum 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  */
  36 enum stp_packet_flags {
  37         STP_PACKET_MARKED       = 0x1,
  38         STP_PACKET_TIMESTAMPED  = 0x2,
  39 };
  40
  41 struct stp_policy;
  42
  43 struct 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  */
  81 struct 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
 103 int stm_register_device(struct device *parent, struct stm_data *stm_data,
 104                         struct module *owner);
 105 void stm_unregister_device(struct stm_data *stm_data);
 106
 107 struct 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  */
 120 struct 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
 129 int stm_source_register_device(struct device *parent,
 130                                struct stm_source_data *data);
 131 void stm_source_unregister_device(struct stm_source_data *data);
 132
 133 int stm_source_write(struct stm_source_data *data, unsigned int chan,
 134                      const char *buf, size_t count);
 135
 136 #endif /* _STM_H_ */