Coresight overview
This article explains how Coresight IP is composed, how to configure it, and how to use it.
目录
Framework purpose
ARM Coresight products include a wide range of trace macrocells for ARM processors, system and software instrumentation and a comprehensive set of IP blocks to enable the debug & trace of the most complex, multi-core SoCs. ARM has defined an open CoreSight architecture to allow SoC designers to add debug & trace capabilities for other IP cores in to the CoreSight infrastructure.
Coresight can be used in many different use cases, as mentioned in How to use Coresight section
System overview
Component description
The debug features are based on Arm® CoreSight™ components:
• SWJ-DP: JTAG/Serial-wire debug port
• AXI-AP: AXI access port
• AHB-AP: AHB access port
• APB-AP: APB access port
• ITM: Instrumentation Trace Macrocell
• DWT: Data Watchpoint and Trace
• ETM: Embedded Trace Macrocell
• ETF: Embedded Trace FIFO
• TPIU: Trace Port Interface Unit
• SWO: Serial Wire Output
• CTI: Cross Trigger Interface
• CTM: Cross Trigger Matrix
• Timestamp Generator
• STM: System Trace Macrocell
More information about these components can be found in the Arm® documents referenced [1]
Configuration
Kernel configuration
The Coresight feature is activated by default in ST deliveries. Nevertheless, if a specific configuration is required, you can use Linux Menuconfig tool: Menuconfig or how to configure kernel and select:
For Coresight features:
[*] Device Drivers
[*] HW tracing support
[*] STM (System Trace Module devices)
[*] Kernel console over STM devices
[*] Copy the output from kernel Ftrace to STM engine
[*] Kernel hacking
[*] CoreSight Tracing Support
[*] CoreSight Link and Sink drivers
[*] Coresight generic TMC driver
[*] Coresight generic TPIU driver
[*] Coresight ETBv1.0 driver
[*] CoreSight Embedded Trace Macrocell 3.x driver
[*] CoreSight System Trace Macrocell driver
Device tree configuration
DT bindings documentation deals with all required or optional device tree properties.
Detailed DT configuration for STM32 internal peripherals: Coresight device tree configuration.
How to use Coresight
How to use the Coresight user space interface
Please see examples based on the following use cases:
How to trace and debug the framework
How to monitor
How to monitor with sysfs
sysfs entry can be used to browse Coresight components.
Board $> /sys/bus/coresight# ls devices drivers drivers_autoprobe drivers_probe uevent Board $> /sys/bus/coresight# ls devices/ 50091000.funnel 50092000.etf 50093000.tpiu 500a0000.stm 500dc000.etm 500dd000.etm replicator
How to trace
Coresight Framework print out info and error messages. You can display them with dmesg command:
Board $> dmesg | grep coresight [ 2.510368] coresight-etm3x 500dc000.etm: ETM 3.5 initialized [ 2.515415] coresight-etm3x 500dd000.etm: ETM 3.5 initialized [ 2.521087] coresight-stm 500a0000.stm: stm_register_device failed, probing deffered [ 3.065495] coresight-stm 500a0000.stm: STM500 initialized
How to debug
Source code location
The source files are located inside the Linux kernel.
References
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↑ [1. IHI 0031C (ID080813) - Arm® Debug Interface Architecture Specification ADIv5.0 to
ADIv5.2, Issue C, 8th Aug 2013.
2. DDI 0480F (ID100313) - Arm® CoreSight™ SoC-400 r3p1 Technical Reference Manual, Issue F, 26th Sept 2013.
3. DDI 0461B (ID010111) - Arm® CoreSight™ Trace Memory Controller r0p1 Technical Reference Manual, Issue B, 10 Dec 2010
4. DDI 0314H - Arm® CoreSight™ Components Technical Reference Manual, Issue H, 10 July, 2009
5. DDI 0403D (ID100710) - Arm® v7-M Architecture Reference Manual, Issue Derrata2010_Q3, November 2010
6. DDI 0468A (ID101712) - Arm® CoreSight™ ETM™-A7 r0p0, Issue A, 12 Sept 2011
7. DDI 0440C (ID070610) - Arm® CoreSight™ ETM™-M4 r0p1 Technical Reference Manual, Issue C, 29 June 2012
8. DDI 0528B (ID062514) - Arm® CoreSight™ STM-500 System Trace Macrocell r0p1 Technical Reference Manual, Issue B, 11 March 2014
9. DDI 0464F (ID051113) - Arm® Cortex®-A7 MPCore™ r0p5 Technical Reference Manual, Issue F, 11 April 2013],Arm® documents referenced
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