Hi,
On Thu, 27 Feb 2025 at 09:27, songchai quic_songchai@quicinc.com wrote:
Provide support for the TGU (Trigger Generation Unit), which can be utilized to sense a plurality of signals and create a trigger into the CTI or generate interrupts to processors once the input signal meets the conditions. We can treat the TGU’s workflow as a flowsheet, it has some “steps” regions for customization. In each step region, we can set the signals that we want with priority in priority_group, set the conditions in each step via condition_decode, and set the resultant action by condition_select. Meanwhile, some TGUs (not all) also provide timer/counter functionality. Based on the characteristics described above, we consider the TGU as a helper in the CoreSight subsystem. Its master device is the TPDM, which can transmit signals from other subsystems, and we reuse the existing ports mechanism to link the TPDM to the connected TGU.
I do not believe that his component is part of the Coresight subsystem.
1) It inputs multiple signals from the SoC to process and create an trigger event - however, it can do this irrespective of CoreSight trace being operational, especially where generating interrupts for processors, or triggers for other non-coresight components. It would appear that the TPDM can send output to more than just the TDPA which generates coresight trace packets - a previously undisclosed feature.
2) The ports mechanism is a generic device tree mechanism, not something unique to the Coresight subsystem.
3) The CTI trigger connection will be defined in devicetree under the CTI component, as this is the interface between this component and coresight.
As such this seems more like a general performance and debug component, with optional inputs to the coresight trigger mechanisms, rather than being a coresight component itself. Other SoCs have non-coresight component inputs to CTIs. For example the PL011 serial device on Juno has a signal into one of the system CTIs.
Here is a detailed example to explain how to use the TGU:
In this example, the TGU is configured to use 2 conditions, 2 steps, and the timer. The goal is to look for one of two patterns which are generated from TPDM, giving priority to one, and then generate a trigger once the timer reaches a certain value. In other words, two conditions are used for the first step to look for the two patterns, where the one with the highest priority is used in the first condition. Then, in the second step, the timer is enabled and set to be compared to the given value at each clock cycle. These steps are better shown below.
|-----------------| | | | TPDM | | | |-----------------| | |
| | | | | |--------------------| | | |---- ---> | | Go to next steps | | | | | |--- ---> | Enable timer | | | | v | | | | | | |-----------------| | |--------------------| | | | | | Yes | | | | | | inputs==0xB | ----->| | <-------- | | | | | | | No | | | No | |-----------------| | v | | | | | | |-----------------| | | | | | | | | | | | | | | | timer>=3 |-- | | | v | | | | | | |-----------------| | |-----------------| | | | | | Yes | | | | |--- | inputs==0xA | ----->| | Yes | | | | | | | |-----------------| v | | |-----------------| | | | | | | | Trigger | | | | | | | |-----------------| | | TGU | | |--- --- --- --- --- --- --- --- --- --- --- --- --- --- |--- --- -- | | v |-----------------| |The controllers | |which will use | |triggers further | |-----------------|
steps: 1. Reset TGU /*it will disable tgu and reset dataset*/ - echo 1 > /sys/bus/coresight/devices/<tgu-name>/reset_tgu
2. Set the pattern match for priority0 to 0xA = 0b1010 and for priority 1 to 0xB = 0b1011. - echo 0x11113232 > /sys/bus/coresight/devices/<tgu-name>/step0_priority0/reg0 - echo 0x11113233 > /sys/bus/coresight/devices/<tgu-name>/step0_priority1/reg0 Note: Bit distribution diagram for each priority register |-------------------------------------------------------------------| | Bits | Field Nam | Description | |-------------------------------------------------------------------| | | | 00 = bypass for OR output | | 29:28 | SEL_BIT7_TYPE2 | 01 = bypass for AND output | | | | 10 = sense input '0' is true| | | | 11 = sense input '1' is true| |-------------------------------------------------------------------| | | | 00 = bypass for OR output | | 25:24 | SEL_BIT6_TYPE2 | 01 = bypass for AND output | | | | 10 = sense input '0' is true| | | | 11 = sense input '1' is true| |-------------------------------------------------------------------| | | | 00 = bypass for OR output | | 21:20 | SEL_BIT5_TYPE2 | 01 = bypass for AND output | | | | 10 = sense input '0' is true| | | | 11 = sense input '1' is true| |-------------------------------------------------------------------| | | | 00 = bypass for OR output | | 17:16 | SEL_BIT4_TYPE2 | 01 = bypass for AND output | | | | 10 = sense input '0' is true| | | | 11 = sense input '1' is true| |-------------------------------------------------------------------| | | | 00 = bypass for OR output | | 13:12 | SEL_BIT3_TYPE2 | 01 = bypass for AND output | | | | 10 = sense input '0' is true| | | | 11 = sense input '1' is true| |-------------------------------------------------------------------| | | | 00 = bypass for OR output | | 9:8 | SEL_BIT2_TYPE2 | 01 = bypass for AND output | | | | 10 = sense input '0' is true| | | | 11 = sense input '1' is true| |-------------------------------------------------------------------| | | | 00 = bypass for OR output | | 5:4 | SEL_BIT1_TYPE2 | 01 = bypass for AND output | | | | 10 = sense input '0' is true| | | | 11 = sense input '1' is true| |-------------------------------------------------------------------| | | | 00 = bypass for OR output | | 1:0 | SEL_BIT0_TYPE2 | 01 = bypass for AND output | | | | 10 = sense input '0' is true| | | | 11 = sense input '1' is true| |-------------------------------------------------------------------| These bits are used to identify the signals we want to sense, with a maximum signal number of 140. For example, to sense the signal 0xA (binary 1010), we set the value of bits 0 to 13 to 3232, which represents 1010. The remaining bits are set to 1, as we want to use AND gate to summarize all the signals we want to sense here. For rising or falling edge detection of any input to the priority, set the remaining bits to 0 to use an OR gate. 3. look for the pattern for priority_i i=0,1. - echo 0x3 > /sys/bus/coresight/devices/<tgu-name>/step0_condition_decode/reg0 - echo 0x30 > /sys/bus/coresight/devices/<tgu-name>/step0_condition_decode/reg1 |-------------------------------------------------------------------------------| | Bits | Field Nam | Description | |-------------------------------------------------------------------------------| | | |For each decoded condition, this | | 24 | NOT |inverts the output. If the condition | | | |decodes to true, and the NOT field | | | |is '1', then the output is NOT true. | |-------------------------------------------------------------------------------| | | |When '1' the output from the associated| | 21 | BC0_COMP_ACTIVE |comparator will be actively included in| | | |the decoding of this particular | | | |condition. | |-------------------------------------------------------------------------------| | | |When '1' the output from the associated| | | |comparator will need to be 1 to affect | | 20 | BC0_COMP_HIGH |the decoding of this condition. | | | |Conversely, a '0' here requires a '0' | | | |from the comparator | |-------------------------------------------------------------------------------| | | |When '1' the output from the associated| | 17 | |comparator will be actively included in| | | TC0_COMP_ACTIVE |the decoding of this particular | | | |condition. | |-------------------------------------------------------------------------------| | | |When '1' the output from the associated| | | |comparator will need to be 1 to affect | | 16 | TC0_COMP_HIGH |the decoding of this particular | | | |condition.Conversely, a 0 here | | | |requires a '0' from the comparator | |-------------------------------------------------------------------------------| | | |When '1' the output from Priority_n | | | |OR logic will be actively | | 4n+3 | Priority_n_OR_ACTIVE|included in the decoding of | | | (n=0,1,2,3) |this particular condition. | | | | | |-------------------------------------------------------------------------------| | | |When '1' the output from Priority_n | | | |will need to be '1' to affect the | | 4n+2 | Priority_n_OR_HIGH |decoding of this particular | | | (n=0,1,2,3) |condition. Conversely, a '0' here | | | |requires a '0' from Priority_n OR logic| |-------------------------------------------------------------------------------| | | |When '1' the output from Priority_n | | | |AND logic will be actively | | 4n+1 |Priority_n_AND_ACTIVE|included in the decoding of this | | | (n=0,1,2,3) |particular condition. | | | | | |-------------------------------------------------------------------------------| | | |When '1' the output from Priority_n | | | |AND logic will need to be '1' to | | 4n | Priority_n_AND_HIGH |affect the decoding of this | | | (n=0,1,2,3) |particular condition. Conversely, | | | |a '0' here requires a '0' from | | | |Priority_n AND logic. | |-------------------------------------------------------------------------------| Since we use `priority_0` and `priority_1` with an AND output in step 2, we set `0x3` and `0x30` here to activate them. 4. Set NEXT_STEP = 1 and TC0_ENABLE = 1 so that when the conditions are met then the next step will be step 1 and the timer will be enabled. - echo 0x20008 > /sys/bus/coresight/devices/<tgu-name>/step0_condition_select/reg0 - echo 0x20008 > /sys/bus/coresight/devices/<tgu-name>/step0_condition_select/reg1 |-----------------------------------------------------------------------------| | Bits | Field Nam | Description | |-----------------------------------------------------------------------------| | | |This field defines the next step the | | 18:17 | NEXT_STEP |TGU will 'goto' for the associated | | | |Condition and Step. | |-----------------------------------------------------------------------------| | | |For each possible output trigger | | 13 | TRIGGER |available, set a '1' if you want | | | |the trigger to go active for the | | | |associated condition and Step. | |-----------------------------------------------------------------------------| | | |This will cause BC0 to increment if the| | 9 | BC0_INC |associated Condition is decoded for | | | |this step. | |-----------------------------------------------------------------------------| | | |This will cause BC0 to decrement if the| | 8 | BC0_DEC |associated Condition is decoded for | | | |this step. | |-----------------------------------------------------------------------------| | | |This will clear BC0 count value to 0 if| | 7 | BC0_CLEAR |the associated Condition is decoded | | | |for this step. | |-----------------------------------------------------------------------------| | | |This will cause TC0 to increment until | | 3 | TC0_ENABLE |paused or cleared if the associated | | | |Condition is decoded for this step. | |-----------------------------------------------------------------------------| | | |This will cause TC0 to pause until | | 2 | TC0_PAUSE |enabled if the associated Condition | | | |is decoded for this step. | |-----------------------------------------------------------------------------| | | |This will clear TC0 count value to 0 | | 1 | TC0_CLEAR |if the associated Condition is | | | |decoded for this step. | |-----------------------------------------------------------------------------| | | |This will set the done signal to the | | 0 | DONE |TGU FSM if the associated Condition | | | |is decoded for this step. | |-----------------------------------------------------------------------------| Based on the distribution diagram, we set `0x20008` for `priority0` and `priority1` to achieve "jump to step 1 and enable TC0" once the signal is sensed. 5. activate the timer comparison for this step. - echo 0x30000 > /sys/bus/coresight/devices/<tgu-name>/step1_condition_decode/reg0 |-------------------------------------------------------------------------------| | | |When '1' the output from the associated| | 17 | |comparator will be actively included in| | | TC0_COMP_ACTIVE |the decoding of this particular | | | |condition. | |-------------------------------------------------------------------------------| | | |When '1' the output from the associated| | | |comparator will need to be 1 to affect | | 16 | TC0_COMP_HIGH |the decoding of this particular | | | |condition.Conversely, a 0 here | | | |requires a '0' from the comparator | |-------------------------------------------------------------------------------| Accroding to the decode distribution diagram , we give 0x30000 here to set 16th&17th bit to enable timer comparison. 6. Set the NEXT_STEP = 0 and TC0_PAUSE = 1 and TC0_CLEAR = 1 once the timer has reached the given value. - echo 0x6 > /sys/bus/coresight/devices/<tgu-name>/step1_condition_select/reg0 7. Enable Trigger 0 for TGU when the condition 0 is met in step1, i.e. when the timer reaches 3. - echo 0x2000 > /sys/bus/coresight/devices/<tgu-name>/step1_condition_select/default Note: 1. 'default' register allows for establishing the resultant action for the default condition 2. Trigger:For each possible output trigger available from the Design document, there are three triggers: interrupts, CTI, and Cross-TGU mapping.All three triggers can occur, but the choice of which trigger to use depends on the user's needs. 8. Compare the timer to 3 in step 1. - echo 0x3 > /sys/bus/coresight/devices/<tgu-name>/step1_timer/reg0 9. enale tgu - echo 1 > /sys/bus/coresight/devices/<tgu-name>/enable_tgu
If this is version 3 - where is the list of differences from versions 1 - 2?
Songwei Chai (7): dt-bindings: arm: Add support for Coresight TGU trace coresight: Add coresight TGU driver coresight-tgu: Add signal priority support coresight-tgu: Add TGU decode support coresight-tgu: add support to configure next action coresight-tgu: add timer/counter functionality for TGU coresight-tgu: add reset node to initialize
.../testing/sysfs-bus-coresight-devices-tgu | 51 ++ .../bindings/arm/qcom,coresight-tgu.yaml | 135 ++++ drivers/hwtracing/coresight/Kconfig | 11 + drivers/hwtracing/coresight/Makefile | 1 + drivers/hwtracing/coresight/coresight-tgu.c | 669 ++++++++++++++++++ drivers/hwtracing/coresight/coresight-tgu.h | 242 +++++++ 6 files changed, 1109 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-bus-coresight-devices-tgu create mode 100644 Documentation/devicetree/bindings/arm/qcom,coresight-tgu.yaml create mode 100644 drivers/hwtracing/coresight/coresight-tgu.c create mode 100644 drivers/hwtracing/coresight/coresight-tgu.h
Regards
Mike
-- Mike Leach Principal Engineer, ARM Ltd. Manchester Design Centre. UK