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 */
15 enum 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 */
28 enum stp_packet_flags {
29 STP_PACKET_MARKED = 0x1,
30 STP_PACKET_TIMESTAMPED = 0x2,
31 };
32
33 /**
34 * enum stm_source_type - STM source driver
35 * @STM_USER: any STM trace source
36 * @STM_FTRACE: ftrace STM source
37 */
38 enum stm_source_type {
39 STM_USER,
40 STM_FTRACE,
41 };
42
43 struct stp_policy;
44
45 struct stm_device;
46
47 /**
48 * struct stm_data - STM device description and callbacks
49 * @name: device name
50 * @stm: internal structure, only used by stm class code
51 * @sw_start: first STP master available to software
52 * @sw_end: last STP master available to software
53 * @sw_nchannels: number of STP channels per master
54 * @sw_mmiosz: size of one channel's IO space, for mmap, optional
55 * @hw_override: masters in the STP stream will not match the ones
56 * assigned by software, but are up to the STM hardware
57 * @packet: callback that sends an STP packet
58 * @mmio_addr: mmap callback, optional
59 * @link: called when a new stm_source gets linked to us, optional
60 * @unlink: likewise for unlinking, again optional
61 * @set_options: set device-specific options on a channel
62 *
63 * Fill out this structure before calling stm_register_device() to create
64 * an STM device and stm_unregister_device() to destroy it. It will also be
65 * passed back to @packet(), @mmio_addr(), @link(), @unlink() and @set_options()
66 * callbacks.
67 *
68 * Normally, an STM device will have a range of masters available to software
69 * and the rest being statically assigned to various hardware trace sources.
70 * The former is defined by the range [@sw_start..@sw_end] of the device
71 * description. That is, the lowest master that can be allocated to software
72 * writers is @sw_start and data from this writer will appear is @sw_start
73 * master in the STP stream.
74 *
75 * The @packet callback should adhere to the following rules:
76 * 1) it must return the number of bytes it consumed from the payload;
77 * 2) therefore, if it sent a packet that does not have payload (like FLAG),
78 * it must return zero;
79 * 3) if it does not support the requested packet type/flag combination,
80 * it must return -ENOTSUPP.
81 *
82 * The @unlink callback is called when there are no more active writers so
83 * that the master/channel can be quiesced.
84 */
85 struct stm_data {
86 const char *name;
87 struct stm_device *stm;
88 unsigned int sw_start;
89 unsigned int sw_end;
90 unsigned int sw_nchannels;
91 unsigned int sw_mmiosz;
92 unsigned int hw_override;
93 ssize_t (*packet)(struct stm_data *, unsigned int,
94 unsigned int, unsigned int,
95 unsigned int, unsigned int,
96 const unsigned char *);
97 phys_addr_t (*mmio_addr)(struct stm_data *, unsigned int,
98 unsigned int, unsigned int);
99 int (*link)(struct stm_data *, unsigned int,
100 unsigned int);
101 void (*unlink)(struct stm_data *, unsigned int,
102 unsigned int);
103 long (*set_options)(struct stm_data *, unsigned int,
104 unsigned int, unsigned int,
105 unsigned long);
106 };
107
108 int stm_register_device(struct device *parent, struct stm_data *stm_data,
109 struct module *owner);
110 void stm_unregister_device(struct stm_data *stm_data);
111
112 struct stm_source_device;
113
114 /**
115 * struct stm_source_data - STM source device description and callbacks
116 * @name: device name, will be used for policy lookup
117 * @src: internal structure, only used by stm class code
118 * @nr_chans: number of channels to allocate
119 * @type: type of STM source driver represented by stm_source_type
120 * @link: called when this source gets linked to an STM device
121 * @unlink: called when this source is about to get unlinked from its STM
122 *
123 * Fill in this structure before calling stm_source_register_device() to
124 * register a source device. Also pass it to unregister and write calls.
125 */
126 struct stm_source_data {
127 const char *name;
128 struct stm_source_device *src;
129 unsigned int percpu;
130 unsigned int nr_chans;
131 unsigned int type;
132 int (*link)(struct stm_source_data *data);
133 void (*unlink)(struct stm_source_data *data);
134 };
135
136 int stm_source_register_device(struct device *parent,
137 struct stm_source_data *data);
138 void stm_source_unregister_device(struct stm_source_data *data);
139
140 int notrace stm_source_write(struct stm_source_data *data, unsigned int chan,
141 const char *buf, size_t count);
142
143 #endif /* _STM_H_ */
144
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