trace/coresight/coresight-ect.rst

1 .. SPDX-License-Identifier: GPL-2.0
11 --------------------
21  0 C   0----------->:     :             +======>(other CTI channel IO)
22  0  P  0<-----------:     :             v
24  0000000            : CTI :<=========>*CTM*<====>: CTI :---+
25  #######  in_trigs  :     : (id 0-3)  *****      :::::::   v
26  # ETM #----------->:     :                         ^   #######
27  #     #<-----------:     :                         +---# ETR #
31 channels. When an input trigger becomes active, the attached channel will
32 become active. Any output trigger attached to that channel will also
33 become active. The active channel is propagated to other CTIs via the CTM,
35 channel gate.
37 It is also possible to activate a channel using system software directly
43 no programmed trigger/channel attachments, so will not affect the system
50 The hardware trigger signals can also be connected to non-CoreSight devices
54 single effective CTM (one CTM, or multiple CTMs all interconnected), but it is
60 ---------------------------
78 *Key file items are:-*
82    * ``ctmid`` : associated CTM - only relevant if system has multiple CTI+CTM
84    * ``nr_trigger_cons`` : total connections - triggers<N> directories.
87 *Sub-directories:-*
89    * ``channels``: Contains the channel API - CTI main programming interface.
101 CoreSight and non-CoreSight connections.
119     0-2
123     0-1
134 the multiple register operations that are required if manipulating the
135 'regs' sub-directory elements directly.
158 Attaches trigout(1) to channel(0), then activates channel(0) generating a
164    * ``trigin_attach, trigout_attach``: Attach a channel to a trigger signal.
165    * ``trigin_detach, trigout_detach``: Detach a channel from a trigger signal.
166    * ``chan_set``: Set the channel - the set state will be propagated around
168    * ``chan_clear``: Clear the channel.
169    * ``chan_pulse``: Set the channel for a single CoreSight clock cycle.
171      (enable) the channel to other devices. This operation takes a channel
174    * ``chan_gate_disable``: Write channel number to disable gate for that
175      channel.
178    * ``chan_xtrigs_sel``: write a channel number to select a channel to view,
179      read to show the selected channel number.
181      the selected view channel.
183      the selected view channel.
189    * ``chan_xtrigs_reset``: Write 1 to clear all channel / trigger programming.
193 The example below attaches input trigger index 1 to channel 2, and output
194 trigger index 6 to the same channel. It then examines the state of the
195 channel / trigger connections using the appropriate sysfs attributes.
197 The settings mean that if either input trigger 1, or channel 2 go active then
199 channel control to activate channel 2. We see the active channel on the
201 register. Finally clearing the channel removes this.
208    0-1,3