1// SPDX-License-Identifier: GPL-2.0
2/*
3 * System Trace Module (STM) infrastructure apis
4 * Copyright (C) 2014 Intel Corporation.
5 */
6
7#ifndef _STM_H_
8#define _STM_H_
9
10#include <linux/device.h>
11
12/**
13 * enum stp_packet_type - STP packets that an STM driver sends
14 */
15enum stp_packet_type {
16 STP_PACKET_DATA = 0,
17 STP_PACKET_FLAG,
18 STP_PACKET_USER,
19 STP_PACKET_MERR,
20 STP_PACKET_GERR,
21 STP_PACKET_TRIG,
22 STP_PACKET_XSYNC,
23};
24
25/**
26 * enum stp_packet_flags - STP packet modifiers
27 */
28enum stp_packet_flags {
29 STP_PACKET_MARKED = 0x1,
30 STP_PACKET_TIMESTAMPED = 0x2,
31};
32
33struct stp_policy;
34
35struct stm_device;
36
37/**
38 * struct stm_data - STM device description and callbacks
39 * @name: device name
40 * @stm: internal structure, only used by stm class code
41 * @sw_start: first STP master available to software
42 * @sw_end: last STP master available to software
43 * @sw_nchannels: number of STP channels per master
44 * @sw_mmiosz: size of one channel's IO space, for mmap, optional
45 * @hw_override: masters in the STP stream will not match the ones
46 * assigned by software, but are up to the STM hardware
47 * @packet: callback that sends an STP packet
48 * @mmio_addr: mmap callback, optional
49 * @link: called when a new stm_source gets linked to us, optional
50 * @unlink: likewise for unlinking, again optional
51 * @set_options: set device-specific options on a channel
52 *
53 * Fill out this structure before calling stm_register_device() to create
54 * an STM device and stm_unregister_device() to destroy it. It will also be
55 * passed back to @packet(), @mmio_addr(), @link(), @unlink() and @set_options()
56 * callbacks.
57 *
58 * Normally, an STM device will have a range of masters available to software
59 * and the rest being statically assigned to various hardware trace sources.
60 * The former is defined by the the range [@sw_start..@sw_end] of the device
61 * description. That is, the lowest master that can be allocated to software
62 * writers is @sw_start and data from this writer will appear is @sw_start
63 * master in the STP stream.
64 *
65 * The @packet callback should adhere to the following rules:
66 * 1) it must return the number of bytes it consumed from the payload;
67 * 2) therefore, if it sent a packet that does not have payload (like FLAG),
68 * it must return zero;
69 * 3) if it does not support the requested packet type/flag combination,
70 * it must return -ENOTSUPP.
71 *
72 * The @unlink callback is called when there are no more active writers so
73 * that the master/channel can be quiesced.
74 */
75struct stm_data {
76 const char *name;
77 struct stm_device *stm;
78 unsigned int sw_start;
79 unsigned int sw_end;
80 unsigned int sw_nchannels;
81 unsigned int sw_mmiosz;
82 unsigned int hw_override;
83 ssize_t (*packet)(struct stm_data *, unsigned int,
84 unsigned int, unsigned int,
85 unsigned int, unsigned int,
86 const unsigned char *);
87 phys_addr_t (*mmio_addr)(struct stm_data *, unsigned int,
88 unsigned int, unsigned int);
89 int (*link)(struct stm_data *, unsigned int,
90 unsigned int);
91 void (*unlink)(struct stm_data *, unsigned int,
92 unsigned int);
93 long (*set_options)(struct stm_data *, unsigned int,
94 unsigned int, unsigned int,
95 unsigned long);
96};
97
98int stm_register_device(struct device *parent, struct stm_data *stm_data,
99 struct module *owner);
100void stm_unregister_device(struct stm_data *stm_data);
101
102struct stm_source_device;
103
104/**
105 * struct stm_source_data - STM source device description and callbacks
106 * @name: device name, will be used for policy lookup
107 * @src: internal structure, only used by stm class code
108 * @nr_chans: number of channels to allocate
109 * @link: called when this source gets linked to an STM device
110 * @unlink: called when this source is about to get unlinked from its STM
111 *
112 * Fill in this structure before calling stm_source_register_device() to
113 * register a source device. Also pass it to unregister and write calls.
114 */
115struct stm_source_data {
116 const char *name;
117 struct stm_source_device *src;
118 unsigned int percpu;
119 unsigned int nr_chans;
120 int (*link)(struct stm_source_data *data);
121 void (*unlink)(struct stm_source_data *data);
122};
123
124int stm_source_register_device(struct device *parent,
125 struct stm_source_data *data);
126void stm_source_unregister_device(struct stm_source_data *data);
127
128int notrace stm_source_write(struct stm_source_data *data, unsigned int chan,
129 const char *buf, size_t count);
130
131#endif /* _STM_H_ */
132