On 19/11/2019 23:19, Mike Leach wrote:
Add new document covering CTI / CTM usage in CoreSight. Add section in coresight.rst introducing CTI and CTM modules with link to new document. Signed-off-by: Mike Leach <mike.leach@xxxxxxxxxx> --- .../trace/coresight/coresight-ect.rst | 200 ++++++++++++++++++ Documentation/trace/coresight/coresight.rst | 13 ++ 2 files changed, 213 insertions(+) create mode 100644 Documentation/trace/coresight/coresight-ect.rst diff --git a/Documentation/trace/coresight/coresight-ect.rst b/Documentation/trace/coresight/coresight-ect.rst new file mode 100644 index 000000000000..6448cf910f20 --- /dev/null +++ b/Documentation/trace/coresight/coresight-ect.rst @@ -0,0 +1,200 @@ +============================================= +CoreSight Embedded Cross Trigger (CTI & CTM). +============================================= + + :Author: Mike Leach <mike.leach@xxxxxxxxxx> + :Date: November 2019 +
...
+ +Channels API Directory +~~~~~~~~~~~~~~~~~~~~~~ + +This provides an easy way to attach triggers to channels, without needing +the multiple register operations that are required if manipluating the +'regs' sub-dir elements directly. + +A number of files provide this API:: + + >$ ls ./cti_sys0/channels/ + chan_clear chan_inuse chan_xtrigs_view trigin_detach + chan_free chan_pulse chan_xtrigs_view_sel trigout_attach + chan_gate_disable chan_set trig_filter_enable trigout_detach + chan_gate_enable chan_xtrigs_reset trigin_attach trigout_filtered + +Most access to these elements take the form:: + + echo <chan> [<trigger>] > /<device_path>/<operation> + +where the optional <trigger> is only needed for trigXX_attach | detach +operations. + +e.g.:: + + >$ echo 0 1 > ./cti_sys0/channels/trigout_attach + >$ echo 0 > ./cti_sys0/channels/chan_set + +Attaches trigout(1) to channel(0), then activates channel(0) generating a +set state on cti_sys0.trigout(1) + + +*API operations* + + * ``trigin_attach, trigout_attach``: Attach a channel to a trigger signal. + * ``trigin_detach, trigout_detach``: Detach a channel from a trigger signal. + * ``chan_set``: Set the channel - the set state will be propogated around + the CTM to other connected devices. + * ``chan_clear``: Clear the channel. + * ``chan_pulse``: Set the channel for a single CoreSight clock cycle. + * ``chan_gate_enable``: Write operation sets the CTI gate to propagate + (enable) the channel to other devices. This operation takes a channel + number. CTI gate is enabled for all channels by default at power up. Read + to list the currently enabled channels on the gate. + * ``chan_gate_disable``: Write channel number to disable gate for that + channel. + * ``chan_inuse``: Show the current channels attached to any signal + * ``chan_free``: Show channels with no attached signals. + * ``chan_xtrig_view``: write a channel number to select a channel to view, + read to show the cross triggers programmed for the selected channel. + * ``trig_filter_enable``: Defaults to enabled, disable to allow potentially + dangerous output signals to be set. + * ``trigout_filtered``: Trigger out signals that are prevented from being + set if filtering ``trig_filter_enable`` is enabled. One use is to prevent + accidental ``EDBGREQ`` signals stopping a core. + * ``chan_xtrigs_reset``: Write 1 to clear all channel / trigger programming. + Resets device hardware to default state. + +e.g.:: + + .../cti_sys0/channels# echo 2 1 > trigin_attach + .../cti_sys0/channels# echo 2 6 > trigout_attach
minor nit: It may be a good idea to add a comment to describe what you are doing with the above operations, to avoid looking up and mapping it for someone looking it up. I am not too keen, but it is definitely helpful.
+ .../cti_sys0/channels# cat chan_free + 0-1,3 + .../cti_sys0/channels# cat chan_inuse + 2 + .../cti_sys0/channels# echo 2 > chan_xtrigs_view + .../cti_sys0/channels# cat chan_xtrigs_view + [2] IN: 1 OUT: 6 + .../cti_sys0/# echo 1 > enable + .../cti_sys0/channels# echo 2 > chan_set + .../cti_sys0/channels# cat ../regs/choutstatus + 0x4 + .../cti_sys0/channels# cat ../regs/trigoutstatus + 0x40 + .../cti_sys0/channels# echo 2 > chan_clear
+ .../cti_sys0/channels# cat ../regs/trigoutstatus + 0x0 + .../cti_sys0/channels# cat ../regs/trigoutstatus + 0x0
nit: duplicate lines ? Otherwise: Reviewed-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
