On Mon, Jul 19, 2021 at 07:17:36PM +0800, Qi Liu wrote:
Ultrasoc trace module is a system level solution for tracing, and SMB is the component in trace module to store trace message. This patch brings in a documentation for ultrasoc SMB driver and simple introduces how to use ultrasoc SMB by sysfs interface and perf interface.
Signed-off-by: Qi Liu liuqi115@huawei.com
.../trace/coresight/ultrasoc-trace.rst | 193 ++++++++++++++++++ 1 file changed, 193 insertions(+) create mode 100644 Documentation/trace/coresight/ultrasoc-trace.rst
diff --git a/Documentation/trace/coresight/ultrasoc-trace.rst b/Documentation/trace/coresight/ultrasoc-trace.rst new file mode 100644 index 000000000000..dee133e27bf3 --- /dev/null +++ b/Documentation/trace/coresight/ultrasoc-trace.rst @@ -0,0 +1,193 @@ +======================================================= +Siemens Embedded Analytics - HW Assisted Tracing on SoC +=======================================================
- :Author: Jonathan Zhou Jonathan.zhouwen@huawei.com
Qi Liu <liuqi115@huawei.com>- :Date: July 8th, 2021
+Introduction +------------
+This document is concerned with the Siemens Embedded Analytics Framework, +using for tracing of multiple type SoC. As this module is developed by +Ultrasoc technology, which is acquired by Siemens, we still use "Ultrasoc" +to name document and structures.
+System Memory Buffer is an important component in this Analytics Framework, +it provides a way to buffer and store messages in system memory. It provides +a capability to store messages received on its input message interface to an +area of system memory.
+A typical Siemens trace system would look like the following diagram:
@@@@@@@@@@@@@@ CPU @@@@@@@@@@@@@@############## Coresight ## ETM ############|*********************************** AMBA Advanced Trace Bus (ATB) ******************^***************=============== |=== FUNNEL ==<--- |=======|*@@@@@@@@ TRC @@@@@@@@@@|*
- ************************ Message BUS ***************************
- ******************^************************^****************
| |@@@@@@@@@@@@@@@@@@ | @@@@@@@@@@@@@ Message Engine @ | @ JTAG COM @@@@@@@@@@@@@@@@@@@ | @@@@@@@@@@| |---> @@@@@@@@| @@@@@@@@@@@@@ |@ SMB @ JTAG@@@@@@@@@||*
- **************************** AMBA AXI ****************************
+Acronyms +---------------------------
+Acronyms:
+SMB: System Memory Buffer +TRC: Trace receiver
+Framework and implementation +------------------------------
+SMB is implemented as platform device, each SCCL has one SMB device.
+As TRC receives data from coresight ETM device, SMB can use the following API +to register into coresight framework as a sink device: +.. c:function:: struct coresight_device *coresight_register(struct coresight_desc *desc); +.. c:function:: void coresight_unregister(struct coresight_device *csdev);
+Then users can get trace data by this path: ETM->funnel->SMB. +More information about coresight framework can be found in +Documention/trace/coresight/coresight.rst.
+If everything goes well, the relationship of Embedded Analytics devices will be +described under the sysfs::
- $# ls /sys/bus/platform/devices/
- <HID.smb>:00
- $# ls /sys/bus/coresight/devices/
- etm0 etm14 etm2 etm25 etm30 etm8 funnel4
- etm1 etm15 etm20 etm26 etm31 etm9 funnel5
- etm10 etm16 etm21 etm27 etm4 funnel0 funnel6
- etm11 etm17 etm22 etm28 etm5 funnel1 funnel7
- etm12 etm18 etm23 etm29 etm6 funnel2 sink_smb0
- etm13 etm19 etm24 etm3 etm7 funnel3
- $# ls -l /sys/bus/coresight/devices/funnel0/connections/
- <file details> in:0 -> ../../../../system/cpu/cpu0/ARMHC500:00/etm0
- <file details> in:1 -> ../../../../system/cpu/cpu1/ARMHC500:01/etm1
- <file details> in:2 -> ../../../../system/cpu/cpu2/ARMHC500:02/etm2
- <file details> in:3 -> ../../../../system/cpu/cpu3/ARMHC500:03/etm3
- <file details> nr_links
- <file details> out:0 -> ../../../HISI0391:00/HISI03A1:00/sink_smb0
- $# ls -l /sys/bus/coresight/devices/sink_smb0/connections/
- <file details> in:101 -> ../../../../ARMHC9FE:05/funnel5
- <file details> in:114 -> ../../../../ARMHC9FE:07/funnel7
- <file details> in:121 -> ../../../../ARMHC9FE:03/funnel3
- <file details> in:39 -> ../../../../ARMHC9FE:00/funnel0
- <file details> in:51 -> ../../../../ARMHC9FE:04/funnel4
- <file details> in:61 -> ../../../../ARMHC9FE:06/funnel6
- <file details> in:68 -> ../../../../ARMHC9FE:02/funnel2
- <file details> in:89 -> ../../../../ARMHC9FE:01/funnel1
- <file details> nr_links
+How to use the Embedded Analytics trace module +-----------------------------------------------
+There are two ways to use the Embedded Analytics trace module:
+1. interacting directly with the devices using the sysFS interface. +2. using the perf cmd line tools.
+1) Using the sysFS interface:
+Before trace collection can start, a coresight sink needs to be identified. +There is no limit on the amount of sinks (nor sources) that can be enabled at +any given moment. As a generic operation, all device pertaining to the sink +class will have an "active" entry in sysfs::
- $# ls /sys/bus/coresight/devices/
- etm0 etm14 etm2 etm25 etm30 etm8 funnel4
- etm1 etm15 etm20 etm26 etm31 etm9 funnel5
- etm10 etm16 etm21 etm27 etm4 funnel0 funnel6
- etm11 etm17 etm22 etm28 etm5 funnel1 funnel7
- etm12 etm18 etm23 etm29 etm6 funnel2 sink_smb0
- etm13 etm19 etm24 etm3 etm7 funnel3
- $# ls /sys/bus/coresight/devices/sink_smb0
- connections enable_sink firmware_node power subsystem uevent
- $# echo 1 > /sys/bus/coresight/devices/sink_smb0/enable_sink
- $# cat /sys/bus/coresight/devices/sink_smb0/enable_sink
- 1
+When start trace collection, etm devices corresponding to the enabled sink +should be selected::
- $# echo 1 > /sys/bus/coresight/devices/etm0/enable_source
- $# cat /sys/bus/coresight/devices/etm0/enable_source
- 1
- $# cat /sys/bus/platform/devices/<HID.smb>:00/com_status
- com-type : DOWN-ONLY
- service status : stopped
- interrupt status : 0x00000003
- write point : 0x5437f400 <----- The write pointer is moving
+Trace collection is stopped the same way::
- $# echo 0 > /sys/bus/coresight/devices/etm0/enable_source
- $# echo 0 > /sys/bus/coresight/devices/sink_smb0/enable_sink
+The content of the SMB buffer can be harvested directly from /dev::
- $# dd if=/dev/sink_smb0 of=~/cstrace.bin
- 5233+0 records in
- 5233+0 records out
- 2679296 bytes (2.7 MB) copied, 0.0131708 s, 203 MB/s
- root:/sys/bus/coresight/devices#
+The file cstrace.bin can be decompressed using "ptm2human".
+2) Using perf framework:
+As SMB device has been registered with coresight framework, perf tool can be +used to control Embedded Analytics trace collection, and the method is similar +to using perf to do coresight trace collection.
+The only thing to note is, list of cpus should be correspond to the specified +sink device.
+Example usage of perf::
$# ./perf list pmucs_etm// [Kernel PMU event]- $# ./perf record -e cs_etm/@sink_smb0/ -C 0 --per-thread sleep 2s
- [ perf record: Woken up 2 times to write data ]
- [ perf record: Captured and wrote 0.288 MB perf.data ]
- $# ./perf report
This IP block works like any other sink device and as such I don't really see a need for this documentation - especially since it is mostly conveying the same information already present in coresight.rst.
Thanks, Mathieu
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