[PATCH v2 11/11] coresight: etm4x: docs: Adds detailed document for programming etm4x.

Mike Leach
2019-08-29T21:36:16Z

Add in detailed programmers reference for users wanting to program the
CoreSight ETM 4.x driver using sysfs.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
---
.../coresight/coresight-etm4x-reference.txt | 458 ++++++++++++++++++
1 file changed, 458 insertions(+)
create mode 100644 Documentation/trace/coresight/coresight-etm4x-reference.txt

diff --git a/Documentation/trace/coresight/coresight-etm4x-reference.txt b/Documentation/trace/coresight/coresight-etm4x-reference.txt
new file mode 100644
index 000000000000..f0c370870992
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@@ -0,0 +1,458 @@
+ETMv4 sysfs linux driver programming reference - v2.
+====================================================
+
+Supplement to existing ETMv4 driver documentation.
+
+Sysfs files and directories
+---------------------------
+
+Root: /sys/bus/coresight/devices/etm<N>
+
+
+The following paragraphs explain the association between sysfs files and the
+ETMv4 registers that they effect. Note the register names are given without
+the ‘TRC’ prefix.
+
+File : mode (rw)
+Trace Registers : {CONFIGR + others}
+Notes : Bit select trace features. See ‘mode’ section below. Bits
+ in this will cause equivalent programming of trace config and
+ other registers to enable the features requested.
+Syntax & eg : 'echo bitfield > mode'
+ bitfield up to 32 bits setting trace features.
+Example : $> echo 0x > mode
+
+File : reset (wo)
+Trace Registers : All
+Notes : Reset all programming to trace nothing / no logic programmed.
+Syntax : 'echo 1 > reset'
+
+File : enable_source (wo)
+Trace Registers : PRGCTLR, All hardware regs.
+Notes : >0: Programs up the hardware with the current values held in
+ the driver and enables trace.
+ 0: disable trace hardware.
+Syntax : 'echo 1 > enable_source'
+
+File : cpu (ro)
+Trace Registers : None.
+Notes : CPU ID that this ETM is attached to.
+Example :$> cat cpu
+ $> 0
+
+File : addr_idx (rw)
+Trace Registers : None.
+Notes : Virtual register to index address comparator and range
+ features. Set index for first of the pair in a range.
+Syntax : 'echo idx > addr_idx'
+ Where idx <  nr_addr_cmp x 2
+
+File : addr_range (rw)
+Trace Registers : ACVR[idx, idx+1], VIIECTLR
+Notes : Pair of addresses for a range selected by addr_idx. Include
+ / exclude according to the optional parameter, or if omitted
+ uses the current ‘mode’ setting. Select comparator range in
+ control register. Error if index is odd value.
+Depends : mode, addr_idx
+Syntax : 'echo addr1 addr2 [exclude] > addr_range'
+ Where addr1 and addr2 define the range and addr1 < addr2.
+ Optional exclude value - 0 for include, 1 for exclude.
+Example : $> echo 0x0000 0x2000 0 > addr_range
+
+File : addr_single (rw)
+Trace Registers : ACVR[idx]
+Notes : Set a single address comparator according to addr_idx. This
+ is used if the address comparator is used as part of event
+ generation logic etc.
+Depends : addr_idx
+Syntax : 'echo addr1 > addr_single'
+
+File : addr_start (rw)
+Trace Registers : ACVR[idx], VISSCTLR
+Notes : Set a trace start address comparator according to addr_idx.
+ Select comparator in control register.
+Depends : addr_idx
+Syntax : 'echo addr1 > addr_start'
+
+File : addr_stop (rw)
+Trace Registers : ACVR[idx], VISSCTLR
+Notes : Set a trace stop address comparator according to addr_idx.
+ Select comparator in control register.
+Depends : addr_idx
+Syntax : 'echo addr1 > addr_stop'
+
+File : addr_context (rw)
+Trace Registers : ACATR[idx,{6:4}]
+Notes : Link context ID comparator to address comparator addr_idx
+Depends : addr_idx.
+Syntax : 'echo ctxt_idx > addr_context'
+ Where ctxt_idx is the index of the linked context id / vmid
+ comparator.
+
+File : addr_ctxtype (rw)
+Trace Registers : ACATR[idx,{3:2}]
+Notes : Input value string. Set type for linked context ID comparator
+Depends : addr_idx
+Syntax : 'echo type > addr_ctxtype'
+ Type one of {all, vmid, ctxid, none}
+Example : $> echo ctxid > addr_ctxtype
+
+File : addr_exlevel_s_ns (rw)
+Trace Registers : ACATR[idx,{14:8}]
+Notes : Set the ELx secure and non-secure matching bits for the
+ selected address comparator
+Depends : addr_idx
+Syntax : 'echo val > addr_exlevel_s_ns'
+ val is a 7 bit value for exception levels to exclude. Input
+ value shifted to correct bits in register.
+Example : $> echo 0x4F > addr_exlevel_s_ns
+
+File : addr_instdatatype (rw)
+Trace Registers : ACATR[idx,{1:0}]
+Notes : Set the comparator address type for matching. Driver only
+ supports setting instruction address type.
+Depends : addr_idx
+
+File : addr_cmp_view (ro)
+Trace Registers : ACVR[idx, idx+1], ACATR[idx], VIIECTLR
+Notes : Read the currently selected address comparator. If part of
+ address range then display both addresses.
+Depends : addr_idx
+Syntax : 'cat addr_cmp_view'
+Example : $> cat addr_cmp_view
+ addr_cmp[0] range 0x0 0xffffffffffffffff include ctrl(0x4b00)
+
+File : nr_addr_cmp (ro)
+Trace Registers : From IDR4
+Notes : Number of address comparator pairs
+
+File : sshot_idx (rw)
+Trace Registers : None
+Notes : Select  single shot register set.
+
+File : sshot_ctrl (rw)
+Trace Registers : SSCCR[idx]
+Notes : Access a single shot comparator control register.
+Depends : sshot_idx
+Syntax : 'echo val > sshot_ctrl'
+ Writes val into the selected control register.
+
+File : sshot_status (ro)
+Trace Registers : SSCSR[idx]
+Notes : Read a single shot comparator status register
+Depends : sshot_idx
+Syntax : 'cat sshot_status'
+ Read status.
+Example : $> cat sshot_status
+ 0x1
+
+File : sshot_pe_ctrl (rw)
+Trace Registers : SSPCICR[idx]
+Notes : Access a single shot PE comparator input control register.
+Depends : sshot_idx
+Syntax : echo val > sshot_pe_ctrl
+ Writes val into the selected control register.
+
+File : ns_exlevel_vinst (rw)
+Trace Registers : VICTLR{23:20}
+Notes : Program non-secure exception level filters. Set / clear NS
+ exception filter bits. Setting ‘1’ excludes trace from the
+ exception level.
+Syntax : 'echo bitfield > ns_exlevel_viinst'
+ Where bitfield contains bits to set clear for EL0 to EL2
+Example : %> echo 0x4 > ns_exlevel_viinst
+ ; Exclude EL2 NS trace.
+
+File : vinst_pe_cmp_start_stop (rw)
+Trace Registers : VIPCSSCTLR
+Notes : Access PE start stop comparator input control registers
+
+File : bb_ctrl (rw)
+Trace Registers : BBCTLR
+Notes : Define ranges that Branch Broadcast will operate in.
+ Default (0x0) is all addresses.
+Depends : BB enabled.
+
+File : cyc_threshold (rw)
+Trace Registers : CCCTLR
+Notes : Set the threshold for which cycle counts will be emitted.
+ Error if attempt to set below minimum defined in IDR3, masked
+ to width of valid bits.
+Depends : CC enabled.
+
+File : syncfreq (rw)
+Trace Registers : SYNCPR
+Notes : Set trace synchronisation period. Power of 2 value, 0 (off)
+ or 8-20. Driver defaults to 12 (every 4096 bytes).
+
+File : cntr_idx (rw)
+Trace Registers : none
+Notes : Select the counter to access
+Syntax : 'echo idx > cntr_idx'
+ Where idx <  nr_cntr
+
+File : cntr_ctrl (rw)
+Trace Registers : CNTCTLR[idx]
+Notes : Set counter control value
+Depends : cntr_idx
+Syntax : 'echo val > cntr_ctrl'
+ Where val is per ETMv4 spec.
+
+File : cntrldvr (rw)
+Trace Registers : CNTRLDVR[idx]
+Notes : Set counter reload value
+Depends : cntr_idx
+Syntax : 'echo val > cntrldvr'
+ Where val is per ETMv4 spec.
+
+File : nr_cntr (ro)
+Trace Registers : From IDR5
+Notes : Number of counters implemented.
+
+File : ctxid_idx (rw)
+Trace Registers : None
+Notes : Select the context ID comparator to access
+Syntax : 'echo idx > ctxid_idx'
+ Where idx <  numcidc
+
+File : ctxid_pid (rw)
+Trace Registers : CIDCVR[idx]
+Notes : Set the context ID comparator value
+Depends : ctxid_idx
+
+File : ctxid_masks (rw)
+Trace Registers : CIDCCTLR0, CIDCCTLR1, CIDCVR<0-7>
+Notes : Pair of values to set the byte masks for 1-8 context ID
+ comparators. Automatically clears masked bytes to 0 in CID
+ value registers.
+Syntax : 'echo m3m2m1m0 [m7m6m5m4] > ctxid_masks'
+ 32 bit values made up of mask bytes, where mN represents a
+ byte mask value for Ctxt ID comparator N.
+ Second value not required on systems that have fewer than 4
+ context ID comparators
+
+File : numcidc (ro)
+Trace Registers : From IDR4
+Notes : Number of Context ID comparators
+
+File : vmid_idx (rw)
+Trace Registers : None
+Notes : Select the VM ID comparator to access.
+Syntax : 'echo idx > vmid_idx'
+ Where idx <  numvmidc
+
+File : vmid_val (rw)
+Trace Registers : VMIDCVR[idx]
+Notes : Set the VM ID comparator value
+Depends : vmid_idx
+
+File : vmid_masks (rw)
+Trace Registers : VMIDCCTLR0, VMIDCCTLR1, VMIDCVR<0-7>
+Notes : Pair of values to set the byte masks for 1-8 VM ID
+ comparators. Automatically clears masked bytes to 0 in VMID
+ value registers.
+Syntax : 'echo m3m2m1m0 [m7m6m5m4] > vmid_masks'
+ Where mN represents a byte mask value for VMID comparator N.
+ Second value not required on systems that have fewer than
+ 4 VMID comparators.
+
+File : numvmidc (ro)
+Trace Registers : From IDR4
+Notes : Number of VMID comparators
+
+File : res_idx (rw)
+Trace Registers : None.
+Notes : Select the resource selector control to access. Must be 2 or
+ higher as selectors 0 and 1 are hardwired.
+Syntax : 'echo idx > res_idx'
+ Where 2 <= idx < nr_resource x 2
+
+File : res_ctrl (rw)
+Trace Registers : RSCTLR[idx]
+Notes : Set resource selector control value. Value per ETMv4 spec.
+Depends : res_idx
+Syntax : 'echo val > res_cntr'
+ Where val is per ETMv4 spec.
+
+File : nr_resource (ro)
+Trace Registers : From IDR4
+Notes : Number of resource selector pairs
+
+File : event (rw)
+Trace Registers : EVENTCTRL0R
+Notes : Set up to 4 implemented event fields.
+Syntax : 'echo ev3ev2ev1ev0 > event'
+ Where evN is an 8 bit event field. Up to 4 event fields make up
+ the 32bit input value. Number of valid fields implementation
+ dependent defined in IDR0.
+
+File : event_instren (rw)
+Trace Registers : EVENTCTRL1R
+Notes : Choose events which insert event packets into trace stream.
+Depends : EVENTCTRL0R
+Syntax : 'echo bitfield > event_instren'
+ Where bitfield is up to 4 bits according to number of event
+ fields.
+
+File : event_ts (rw)
+Trace Registers : TSCTLR
+Notes : Set the event that will generate timestamp requests.
+Depends : TS activated
+Syntax : 'echo evfield > event_ts'
+ Where evfield is an 8 bit event selector.
+
+File : seq_idx (rw)
+Trace Registers : None
+Notes : Sequencer event register select - 0 to 2
+
+
+File : seq_state (rw)
+Trace Registers : SEQSTR
+Notes : Sequencer current state - 0 to 3.
+
+File : seq_event (rw)
+Trace Registers : SEQEVR[idx]
+Notes : State transition event registers
+Depends : seq_idx
+Syntax : 'echo evBevF > seq_event'
+ Where evBevF is a 16 bit value made up of two event selectors,
+ evB - back, evF - forwards.
+
+File : seq_reset_event (rw)
+Trace Registers : SEQRSTEVR
+Notes : Sequencer reset event
+Syntax : 'echo evfield > seq_reset_event'
+ Where evfield is an 8 bit event selector.
+
+File : nrseqstate (ro)
+Trace Registers : From IDR5
+Notes : Number of sequencer states (0 or 4)
+
+File : nr_pe_cmp (ro)
+Trace Registers : From IDR4
+Notes : Number of PE comparator inputs
+
+File : nr_ext_inp (ro)
+Trace Registers : From IDR5
+Notes : Number of external inputs
+
+File : nr_ss_cmp (ro)
+Trace Registers : From IDR4
+Notes : Number of Single Shot control registers
+
+Note: When programming any address comparator the driver will tag the
+comparator with a type used - i.e. RANGE, SINGLE, START, STOP. Once this tag
+is set, then only the values can be changed using the same sysfs file / type
+used to program it.
+
+Thus:-
+% echo 0 > addr_idx ; select address comparator 0
+% echo 0x1000 0x5000 0 > addr_range ; set address range on comparators 0 and 1.
+% echo 0x2000 > addr_start ; this will error as comparator 0 is a
+ ; range comparator
+% echo 2 > addr_idx ; select address comparator 2
+% echo 0x2000 > addr_start ; this is OK as comparator 2 is unused,
+% echo 0x3000 > addr_stop ; this will error as comparator 2 a start
+ ; address comparator
+% echo 2 > addr_idx ; select address comparator 3
+% echo 0x3000 > addr_stop ; this is OK
+
+To remove programming on all the comparators (and all the other hardware) use
+the reset parameter:
+
+% echo 1 > reset
+
+The ‘mode’ sysfs parameter.
+---------------------------
+
+This is a bitfield selection parameter that sets the overall trace mode for the
+ETM. The table below describes the bits, using the defines from the driver
+source file, along with a description of the feature these represent. Many
+features are optional and therefore dependent on implementation in the
+hardware.
+
+Bit assignements shown below:-
+
+bit (0) : #define ETM_MODE_EXCLUDE
+description : This is the default value for the include / exclude function when
+ setting address ranges. Set 1 for exclude range. When the mode
+ parameter is set this value is applied to the currently indexed
+ address range.
+
+bit (4) : #define ETM_MODE_BB
+description : Set to enable branch broadcast if supported in hardware [IDR0].
+
+bit (5) : #define ETMv4_MODE_CYCACC
+description : Set to enable cycle accurate trace if supported [IDR0].
+
+bit (6) : ETMv4_MODE_CTXID
+description : Set to enable context ID tracing if supported in hardware [IDR2].
+
+bit (7) : ETM_MODE_VMID
+description : Set to enable virtual machine ID tracing if supported [IDR2].
+
+bit (11) : ETMv4_MODE_TIMESTAMP
+description : Set to enable timestamp generation if supported [IDR0].
+
+bit (12) : ETM_MODE_RETURNSTACK
+description : Set to enable trace return stack use if supported [IDR0].
+
+bit (13-14) : ETM_MODE_QELEM(val)
+description : ‘val’ determines level of Q element support enabled if
+ implemented by the ETM [IDR0]
+
+bit (19) : ETM_MODE_ATB_TRIGGER
+description : Set to enable the ATBTRIGGER bit in the event control register
+ [EVENTCTLR1] if supported [IDR5].
+
+bit (20) : ETM_MODE_LPOVERRIDE
+description : Set to enable the LPOVERRIDE bit in the event control register
+ [EVENTCTLR1], if supported [IDR5].
+
+bit (21) : ETM_MODE_ISTALL_EN
+description : Set to enable the ISTALL bit in the stall control register
+ [STALLCTLR]
+
+bit (23) : ETM_MODE_INSTPRIO
+description : Set to enable the INSTPRIORITY bit in the stall control register
+ [STALLCTLR] , if supported [IDR0].
+
+bit (24) : ETM_MODE_NOOVERFLOW
+description : Set to enable the NOOVERFLOW bit in the stall control register
+ [STALLCTLR], if supported [IDR3].
+
+bit (25) : ETM_MODE_TRACE_RESET
+description : Set to enable the TRCRESET bit in the viewinst control register
+ [VICTLR] , if supported [IDR3].
+
+bit (26) : ETM_MODE_TRACE_ERR
+description : Set to enable the TRCCTRL bit in the viewinst control register
+ [VICTLR].
+
+bit (27) : ETM_MODE_VIEWINST_STARTSTOP
+description : Set the initial state value of the ViewInst start / stop logic
+ in the viewinst control register [VICTLR]
+
+bit (30) : ETM_MODE_EXCL_KERN
+description : Set default trace setup to exclude kernel mode trace (see note a)
+
+bit (31) : ETM_MODE_EXCL_USER
+description : Set default trace setup to exclude user space trace (see note a)
+
+Note a) On startup the ETM is programmed to trace the complete address space
+using address range comparator 0. ‘mode’ bits 30 / 31 modify this setting to
+set EL exclude bits for NS state in either user space (EL0) or kernel space
+(EL1) in the address range comparator. (the default setting excludes all
+secure EL, and NS EL2)
+
+Once the reset parameter has been used, and/or custom programming has been
+implemented - using these bits will result in the EL bits for address
+comparator 0 being set in the same way.
+
+Note b) Bits 2-3, 8-10, 15-16, 18, 22, control features that only work with
+data trace. As A profile data trace is architecturally prohibited in ETMv4,
+these have been omitted here. Possible uses could be where a kernel has
+support for control of R or M profile infrastructure as part of a heterogeneous
+system.
+
+Bits 17, 28-29 are unused.
--
2.17.1