1 .. SPDX-License-Identifier: GPL-2.0
2
3 ===================
4 MIPI SyS-T over STP
5 ===================
6
7 The MIPI SyS-T protocol driver can be used wit
8 generate standardized trace stream. Aside from
9 provides better trace source identification an
10
11 In order to use the MIPI SyS-T protocol driver
12 first, you'll need CONFIG_STM_PROTO_SYS_T.
13
14 Now, you can select which protocol driver you
15 a policy for your STM device, by specifying it
16
17 # mkdir /config/stp-policy/dummy_stm.0:p_sys-t
18
19 In other words, the policy name format is exte
20
21 <device_name>:<protocol_name>.<policy_name>
22
23 With Intel TH, therefore it can look like "0-s
24
25 If the protocol name is omitted, the STM class
26 protocol driver was loaded first.
27
28 You can also double check that everything is w
29
30 # cat /config/stp-policy/dummy_stm.0:p_sys-t.m
31 p_sys-t
32
33 Now, with the MIPI SyS-T protocol driver, each
34 configfs gets a few additional attributes, whi
35 parameters specific to the protocol:
36
37 # mkdir /config/stp-policy/dummy_stm.0:p_sys-t
38 # ls /config/stp-policy/dummy_stm.0:p_sys-t.my
39 channels
40 clocksync_interval
41 do_len
42 masters
43 ts_interval
44 uuid
45
46 The most important one here is the "uuid", whi
47 that will be used to tag all data coming from
48 automatically generated when a new node is cre
49 that you would want to change it.
50
51 do_len switches on/off the additional "payload
52 MIPI SyS-T message header. It is off by defaul
53 marks message boundaries.
54
55 ts_interval and clocksync_interval determine h
56 can pass before we need to include a protocol
57 timestamp in a message header or send a CLOCKS
58
59 See Documentation/ABI/testing/configfs-stp-pol
60 details.
61
62 * [1] https://www.mipi.org/specifications/sys-
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