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Linux 6.18.37 · ABI / testing

CoreSight ETB10 trace sink sysfs ABI

CoreSight ETB10 sink enable, post-trigger Trace RAM word count, hardware context label과 RDP·STS·RRP·RWP·TRG·CTL·FFSR·FFCR management registers를 설명합니다.

Source pathDocumentation/ABI/testing/sysfs-bus-coresight-devices-etb10
Source versionLinux v6.18.37
TranslationDUJINLABS 전문 번역 + 해설

요약·해설과 원문, 전문 번역을 서로 분리했습니다. API 이름, symbol, source path는 원문 표기를 사용합니다.

1. 요약·해설

원문의 핵심 논리와 kernel programming 관점의 보충 설명입니다. 아래의 전문 번역과는 별도로 작성했습니다.

Trace sink와 post-trigger capture

sysfs-bus-coresight-devices-etb10:1-20

enable_sink는 trace path에 ETB sink를 추가·제거하며 multiple sources가 공유할 수 있고, trigger_cntr는 event 뒤 register+1개의 32-bit words를 저장한 후 formatter를 멈춥니다.

Hardware context label

sysfs-bus-coresight-devices-etb10:22-26

label은 ETB device의 hardware context information을 보여 줍니다.

ETB Trace RAM과 formatter registers

sysfs-bus-coresight-devices-etb10:28-88

mgmt files는 Trace RAM depth·status·read/write pointers, trigger·control과 formatter/flush status·control registers를 hardware offset에서 직접 읽습니다.

2. 영어 원문 전체

번역 기준이 된 Linux v6.18.37 원문입니다. 줄 번호는 이 버전의 파일 좌표입니다.

원문 전체 펼치기
1 What: /sys/bus/coresight/devices/<memory_map>.etb/enable_sink
2 Date: November 2014
3 KernelVersion: 3.19
4 Contact: Mathieu Poirier <mathieu.poirier@linaro.org>
5 Description: (RW) Add/remove a sink from a trace path. There can be multiple
6 source for a single sink.
7
8 ex::
9
10 echo 1 > /sys/bus/coresight/devices/20010000.etb/enable_sink
11
12 What: /sys/bus/coresight/devices/<memory_map>.etb/trigger_cntr
13 Date: November 2014
14 KernelVersion: 3.19
15 Contact: Mathieu Poirier <mathieu.poirier@linaro.org>
16 Description: (RW) Disables write access to the Trace RAM by stopping the
17 formatter after a defined number of words have been stored
18 following the trigger event. The number of 32-bit words written
19 into the Trace RAM following the trigger event is equal to the
20 value stored in this register+1 (from ARM ETB-TRM).
21
22 What: /sys/bus/coresight/devices/<memory_map>.etb/label
23 Date: Aug 2025
24 KernelVersion 6.18
25 Contact: Mao Jinlong <quic_jinlmao@quicinc.com>
26 Description: (Read) Show hardware context information of device.
27
28 What: /sys/bus/coresight/devices/<memory_map>.etb/mgmt/rdp
29 Date: March 2016
30 KernelVersion: 4.7
31 Contact: Mathieu Poirier <mathieu.poirier@linaro.org>
32 Description: (Read) Defines the depth, in words, of the trace RAM in powers of
33 2. The value is read directly from HW register RDP, 0x004.
34
35 What: /sys/bus/coresight/devices/<memory_map>.etb/mgmt/sts
36 Date: March 2016
37 KernelVersion: 4.7
38 Contact: Mathieu Poirier <mathieu.poirier@linaro.org>
39 Description: (Read) Shows the value held by the ETB status register. The value
40 is read directly from HW register STS, 0x00C.
41
42 What: /sys/bus/coresight/devices/<memory_map>.etb/mgmt/rrp
43 Date: March 2016
44 KernelVersion: 4.7
45 Contact: Mathieu Poirier <mathieu.poirier@linaro.org>
46 Description: (Read) Shows the value held by the ETB RAM Read Pointer register
47 that is used to read entries from the Trace RAM over the APB
48 interface. The value is read directly from HW register RRP,
49 0x014.
50
51 What: /sys/bus/coresight/devices/<memory_map>.etb/mgmt/rwp
52 Date: March 2016
53 KernelVersion: 4.7
54 Contact: Mathieu Poirier <mathieu.poirier@linaro.org>
55 Description: (Read) Shows the value held by the ETB RAM Write Pointer register
56 that is used to sets the write pointer to write entries from
57 the CoreSight bus into the Trace RAM. The value is read directly
58 from HW register RWP, 0x018.
59
60 What: /sys/bus/coresight/devices/<memory_map>.etb/mgmt/trg
61 Date: March 2016
62 KernelVersion: 4.7
63 Contact: Mathieu Poirier <mathieu.poirier@linaro.org>
64 Description: (Read) Similar to "trigger_cntr" above except that this value is
65 read directly from HW register TRG, 0x01C.
66
67 What: /sys/bus/coresight/devices/<memory_map>.etb/mgmt/ctl
68 Date: March 2016
69 KernelVersion: 4.7
70 Contact: Mathieu Poirier <mathieu.poirier@linaro.org>
71 Description: (Read) Shows the value held by the ETB Control register. The value
72 is read directly from HW register CTL, 0x020.
73
74 What: /sys/bus/coresight/devices/<memory_map>.etb/mgmt/ffsr
75 Date: March 2016
76 KernelVersion: 4.7
77 Contact: Mathieu Poirier <mathieu.poirier@linaro.org>
78 Description: (Read) Shows the value held by the ETB Formatter and Flush Status
79 register. The value is read directly from HW register FFSR,
80 0x300.
81
82 What: /sys/bus/coresight/devices/<memory_map>.etb/mgmt/ffcr
83 Date: March 2016
84 KernelVersion: 4.7
85 Contact: Mathieu Poirier <mathieu.poirier@linaro.org>
86 Description: (Read) Shows the value held by the ETB Formatter and Flush Control
87 register. The value is read directly from HW register FFCR,
88 0x304.
89

3. 한국어 전문 번역

영어 원문의 문단 순서와 의미를 유지한 전체 번역입니다. 코드, 함수명, symbol과 URL은 원문 표기를 유지합니다.

ETB trace sink enable과 trigger counter

1-20
WhatDateKernelVersionContact전문 번역
/sys/bus/coresight/devices/<memory_map>.etb/enable_sink2014년 11월3.19Mathieu Poirier <mathieu.poirier@linaro.org>(RW) Trace path에 sink를 추가하거나 제거합니다. 하나의 sink에 multiple source가 있을 수 있습니다.
/sys/bus/coresight/devices/<memory_map>.etb/trigger_cntr2014년 11월3.19Mathieu Poirier <mathieu.poirier@linaro.org>(RW) Trigger event 뒤 정의된 word 수를 저장한 후 formatter를 멈춰 Trace RAM에 대한 write access를 disable합니다. Trigger event 뒤 Trace RAM에 쓰는 32-bit word 수는 이 register에 저장된 값 + 1과 같습니다(ARM ETB-TRM 기준).

Sink enable 원문 예시는 다음과 같습니다.

echo 1 > /sys/bus/coresight/devices/20010000.etb/enable_sink
ETB sink capture path
Trace source ACoreSight trace pathETB sinkTrace RAM
Trace source BCoreSight trace pathETB sink
Trigger eventWrite trigger_cntr + 1 wordsStop formatterDisable Trace RAM writes

여러 trace source가 하나의 ETB Trace RAM으로 합류하고 trigger 뒤 정해진 word 수만 더 기록한 후 formatter가 멈춘다.

ETB hardware context label

22-26
항목전문 번역
What/sys/bus/coresight/devices/<memory_map>.etb/label
Date2025년 8월
KernelVersion6.18
ContactMao Jinlong <quic_jinlmao@quicinc.com>
Description(Read) Device의 hardware context information을 보여 줍니다.

ETB management register views

28-88
공통 항목내용
Date2016년 3월
KernelVersion4.7
ContactMathieu Poirier <mathieu.poirier@linaro.org>
WhatHW registerOffset전문 번역
/sys/bus/coresight/devices/<memory_map>.etb/mgmt/rdpRDP0x004(Read) Trace RAM의 word 단위 depth를 2의 거듭제곱으로 정의합니다. Hardware RDP register에서 값을 직접 읽습니다.
/sys/bus/coresight/devices/<memory_map>.etb/mgmt/stsSTS0x00C(Read) ETB status register가 담은 값을 보여 줍니다. Hardware STS register에서 직접 읽습니다.
/sys/bus/coresight/devices/<memory_map>.etb/mgmt/rrpRRP0x014(Read) APB interface를 통해 Trace RAM entry를 읽을 때 사용하는 ETB RAM Read Pointer register의 값을 보여 줍니다. Hardware RRP register에서 직접 읽습니다.
/sys/bus/coresight/devices/<memory_map>.etb/mgmt/rwpRWP0x018(Read) CoreSight bus에서 Trace RAM으로 entry를 쓸 write pointer를 설정하는 ETB RAM Write Pointer register의 값을 보여 줍니다. Hardware RWP register에서 직접 읽습니다.
/sys/bus/coresight/devices/<memory_map>.etb/mgmt/trgTRG0x01C(Read) 위의 trigger_cntr와 비슷하지만 hardware TRG register에서 값을 직접 읽습니다.
/sys/bus/coresight/devices/<memory_map>.etb/mgmt/ctlCTL0x020(Read) ETB Control register가 담은 값을 보여 줍니다. Hardware CTL register에서 직접 읽습니다.
/sys/bus/coresight/devices/<memory_map>.etb/mgmt/ffsrFFSR0x300(Read) ETB Formatter and Flush Status register가 담은 값을 보여 줍니다. Hardware FFSR register에서 직접 읽습니다.
/sys/bus/coresight/devices/<memory_map>.etb/mgmt/ffcrFFCR0x304(Read) ETB Formatter and Flush Control register가 담은 값을 보여 줍니다. Hardware FFCR register에서 직접 읽습니다.
ETB Trace RAM pointers와 interfaces
CoreSight bus trace entriesRWP at 0x018Trace RAM
Trace RAMRRP at 0x014APB interface reader
RDP at 0x004Trace RAM depth in words
FormatterFFSR status at 0x300FFCR control at 0x304

CoreSight bus write pointer와 APB read pointer가 같은 Trace RAM을 서로 다른 방향으로 접근한다.