diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-coresight-devices-etb10 | 24 | ||||
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-coresight-devices-etm3x | 253 | ||||
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-coresight-devices-funnel | 12 | ||||
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-coresight-devices-tmc | 8 | ||||
| -rw-r--r-- | Documentation/DocBook/uio-howto.tmpl | 2 | ||||
| -rw-r--r-- | Documentation/devicetree/bindings/arm/coresight.txt | 204 | ||||
| -rw-r--r-- | Documentation/trace/coresight.txt | 299 |
7 files changed, 801 insertions, 1 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etb10 b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etb10 new file mode 100644 index 000000000000..4b8d6ec92e2b --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etb10 @@ -0,0 +1,24 @@ +What: /sys/bus/coresight/devices/<memory_map>.etb/enable_sink +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Add/remove a sink from a trace path. There can be multiple + source for a single sink. + ex: echo 1 > /sys/bus/coresight/devices/20010000.etb/enable_sink + +What: /sys/bus/coresight/devices/<memory_map>.etb/status +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (R) List various control and status registers. The specific + layout and content is driver specific. + +What: /sys/bus/coresight/devices/<memory_map>.etb/trigger_cntr +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Disables write access to the Trace RAM by stopping the + formatter after a defined number of words have been stored + following the trigger event. The number of 32-bit words written + into the Trace RAM following the trigger event is equal to the + value stored in this register+1 (from ARM ETB-TRM). diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm3x b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm3x new file mode 100644 index 000000000000..b4d0b99afffb --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm3x @@ -0,0 +1,253 @@ +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/enable_source +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Enable/disable tracing on this specific trace entiry. + Enabling a source implies the source has been configured + properly and a sink has been identidifed for it. The path + of coresight components linking the source to the sink is + configured and managed automatically by the coresight framework. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/status +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (R) List various control and status registers. The specific + layout and content is driver specific. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/addr_idx +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: Select which address comparator or pair (of comparators) to + work with. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/addr_acctype +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Used in conjunction with @addr_idx. Specifies + characteristics about the address comparator being configure, + for example the access type, the kind of instruction to trace, + processor contect ID to trigger on, etc. Individual fields in + the access type register may vary on the version of the trace + entity. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/addr_range +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Used in conjunction with @addr_idx. Specifies the range of + addresses to trigger on. Inclusion or exclusion is specificed + in the corresponding access type register. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/addr_single +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Used in conjunction with @addr_idx. Specifies the single + address to trigger on, highly influenced by the configuration + options of the corresponding access type register. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/addr_start +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Used in conjunction with @addr_idx. Specifies the single + address to start tracing on, highly influenced by the + configuration options of the corresponding access type register. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/addr_stop +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Used in conjunction with @addr_idx. Specifies the single + address to stop tracing on, highly influenced by the + configuration options of the corresponding access type register. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/cntr_idx +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Specifies the counter to work on. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/cntr_event +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Used in conjunction with cntr_idx, give access to the + counter event register. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/cntr_val +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Used in conjunction with cntr_idx, give access to the + counter value register. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/cntr_rld_val +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Used in conjunction with cntr_idx, give access to the + counter reload value register. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/cntr_rld_event +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Used in conjunction with cntr_idx, give access to the + counter reload event register. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/ctxid_idx +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Specifies the index of the context ID register to be + selected. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/ctxid_mask +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Mask to apply to all the context ID comparator. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/ctxid_val +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Used with the ctxid_idx, specify with context ID to trigger + on. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/enable_event +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Defines which event triggers a trace. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/etmsr +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Gives access to the ETM status register, which holds + programming information and status on certains events. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/fifofull_level +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Number of byte left in the fifo before considering it full. + Depending on the tracer's version, can also hold threshold for + data suppression. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/mode +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Interface with the driver's 'mode' field, controlling + various aspect of the trace entity such as time stamping, + context ID size and cycle accurate tracing. Driver specific + and bound to change depending on the driver. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/nr_addr_cmp +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (R) Provides the number of address comparators pairs accessible + on a trace unit, as specified by bit 3:0 of register ETMCCR. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/nr_cntr +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (R) Provides the number of counters accessible on a trace unit, + as specified by bit 15:13 of register ETMCCR. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/nr_ctxid_cmp +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (R) Provides the number of context ID comparator available on a + trace unit, as specified by bit 25:24 of register ETMCCR. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/reset +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (W) Cancels all configuration on a trace unit and set it back + to its boot configuration. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/seq_12_event +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Defines the event that causes the sequencer to transition + from state 1 to state 2. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/seq_13_event +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Defines the event that causes the sequencer to transition + from state 1 to state 3. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/seq_21_event +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Defines the event that causes the sequencer to transition + from state 2 to state 1. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/seq_23_event +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Defines the event that causes the sequencer to transition + from state 2 to state 3. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/seq_31_event +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Defines the event that causes the sequencer to transition + from state 3 to state 1. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/seq_32_event +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Defines the event that causes the sequencer to transition + from state 3 to state 2. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/curr_seq_state +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (R) Holds the current state of the sequencer. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/sync_freq +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Holds the trace synchronization frequency value - must be + programmed with the various implementation behavior in mind. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/timestamp_event +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Defines an event that requests the insertion of a timestamp + into the trace stream. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/traceid +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Holds the trace ID that will appear in the trace stream + coming from this trace entity. + +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/trigger_event +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Define the event that controls the trigger. diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-funnel b/Documentation/ABI/testing/sysfs-bus-coresight-devices-funnel new file mode 100644 index 000000000000..d75acda5e1b3 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-funnel @@ -0,0 +1,12 @@ +What: /sys/bus/coresight/devices/<memory_map>.funnel/funnel_ctrl +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Enables the slave ports and defines the hold time of the + slave ports. + +What: /sys/bus/coresight/devices/<memory_map>.funnel/priority +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Defines input port priority order. diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tmc b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tmc new file mode 100644 index 000000000000..f38cded5fa22 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tmc @@ -0,0 +1,8 @@ +What: /sys/bus/coresight/devices/<memory_map>.tmc/trigger_cntr +Date: November 2014 +KernelVersion: 3.19 +Contact: Mathieu Poirier <mathieu.poirier@linaro.org> +Description: (RW) Disables write access to the Trace RAM by stopping the + formatter after a defined number of words have been stored + following the trigger event. Additional interface for this + driver are expected to be added as it matures. diff --git a/Documentation/DocBook/uio-howto.tmpl b/Documentation/DocBook/uio-howto.tmpl index bbe9c1fd5cef..1fdc246e4256 100644 --- a/Documentation/DocBook/uio-howto.tmpl +++ b/Documentation/DocBook/uio-howto.tmpl @@ -540,7 +540,7 @@ appears in sysfs. </para></listitem> <listitem><para> -<varname>unsigned long size</varname>: Fill in the size of the +<varname>resource_size_t size</varname>: Fill in the size of the memory block that <varname>addr</varname> points to. If <varname>size</varname> is zero, the mapping is considered unused. Note that you <emphasis>must</emphasis> initialize <varname>size</varname> with zero for diff --git a/Documentation/devicetree/bindings/arm/coresight.txt b/Documentation/devicetree/bindings/arm/coresight.txt new file mode 100644 index 000000000000..d790f49066f3 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/coresight.txt @@ -0,0 +1,204 @@ +* CoreSight Components: + +CoreSight components are compliant with the ARM CoreSight architecture +specification and can be connected in various topologies to suit a particular +SoCs tracing needs. These trace components can generally be classified as +sinks, links and sources. Trace data produced by one or more sources flows +through the intermediate links connecting the source to the currently selected +sink. Each CoreSight component device should use these properties to describe +its hardware characteristcs. + +* Required properties for all components *except* non-configurable replicators: + + * compatible: These have to be supplemented with "arm,primecell" as + drivers are using the AMBA bus interface. Possible values include: + - "arm,coresight-etb10", "arm,primecell"; + - "arm,coresight-tpiu", "arm,primecell"; + - "arm,coresight-tmc", "arm,primecell"; + - "arm,coresight-funnel", "arm,primecell"; + - "arm,coresight-etm3x", "arm,primecell"; + + * reg: physical base address and length of the register + set(s) of the component. + + * clocks: the clock associated to this component. + + * clock-names: the name of the clock as referenced by the code. + Since we are using the AMBA framework, the name should be + "apb_pclk". + + * port or ports: The representation of the component's port + layout using the generic DT graph presentation found in + "bindings/graph.txt". + +* Required properties for devices that don't show up on the AMBA bus, such as + non-configurable replicators: + + * compatible: Currently supported value is (note the absence of the + AMBA markee): + - "arm,coresight-replicator" + + * id: a unique number that will identify this replicator. + + * port or ports: same as above. + +* Optional properties for ETM/PTMs: + + * arm,cp14: must be present if the system accesses ETM/PTM management + registers via co-processor 14. + + * cpu: the cpu phandle this ETM/PTM is affined to. When omitted the + source is considered to belong to CPU0. + +* Optional property for TMC: + + * arm,buffer-size: size of contiguous buffer space for TMC ETR + (embedded trace router) + + +Example: + +1. Sinks + etb@20010000 { + compatible = "arm,coresight-etb10", "arm,primecell"; + reg = <0 0x20010000 0 0x1000>; + + coresight-default-sink; + clocks = <&oscclk6a>; + clock-names = "apb_pclk"; + port { + etb_in_port: endpoint@0 { + slave-mode; + remote-endpoint = <&replicator_out_port0>; + }; + }; + }; + + tpiu@20030000 { + compatible = "arm,coresight-tpiu", "arm,primecell"; + reg = <0 0x20030000 0 0x1000>; + + clocks = <&oscclk6a>; + clock-names = "apb_pclk"; + port { + tpiu_in_port: endpoint@0 { + slave-mode; + remote-endpoint = <&replicator_out_port1>; + }; + }; + }; + +2. Links + replicator { + /* non-configurable replicators don't show up on the + * AMBA bus. As such no need to add "arm,primecell". + */ + compatible = "arm,coresight-replicator"; + /* this will show up in debugfs as "0.replicator" */ + id = <0>; + + ports { + #address-cells = <1>; + #size-cells = <0>; + + /* replicator output ports */ + port@0 { + reg = <0>; + replicator_out_port0: endpoint { + remote-endpoint = <&etb_in_port>; + }; + }; + + port@1 { + reg = <1>; + replicator_out_port1: endpoint { + remote-endpoint = <&tpiu_in_port>; + }; + }; + + /* replicator input port */ + port@2 { + reg = <0>; + replicator_in_port0: endpoint { + slave-mode; + remote-endpoint = <&funnel_out_port0>; + }; + }; + }; + }; + + funnel@20040000 { + compatible = "arm,coresight-funnel", "arm,primecell"; + reg = <0 0x20040000 0 0x1000>; + + clocks = <&oscclk6a>; + clock-names = "apb_pclk"; + ports { + #address-cells = <1>; + #size-cells = <0>; + + /* funnel output port */ + port@0 { + reg = <0>; + funnel_out_port0: endpoint { + remote-endpoint = + <&replicator_in_port0>; + }; + }; + + /* funnel input ports */ + port@1 { + reg = <0>; + funnel_in_port0: endpoint { + slave-mode; + remote-endpoint = <&ptm0_out_port>; + }; + }; + + port@2 { + reg = <1>; + funnel_in_port1: endpoint { + slave-mode; + remote-endpoint = <&ptm1_out_port>; + }; + }; + + port@3 { + reg = <2>; + funnel_in_port2: endpoint { + slave-mode; + remote-endpoint = <&etm0_out_port>; + }; + }; + + }; + }; + +3. Sources + ptm@2201c000 { + compatible = "arm,coresight-etm3x", "arm,primecell"; + reg = <0 0x2201c000 0 0x1000>; + + cpu = <&cpu0>; + clocks = <&oscclk6a>; + clock-names = "apb_pclk"; + port { + ptm0_out_port: endpoint { + remote-endpoint = <&funnel_in_port0>; + }; + }; + }; + + ptm@2201d000 { + compatible = "arm,coresight-etm3x", "arm,primecell"; + reg = <0 0x2201d000 0 0x1000>; + + cpu = <&cpu1>; + clocks = <&oscclk6a>; + clock-names = "apb_pclk"; + port { + ptm1_out_port: endpoint { + remote-endpoint = <&funnel_in_port1>; + }; + }; + }; diff --git a/Documentation/trace/coresight.txt b/Documentation/trace/coresight.txt new file mode 100644 index 000000000000..bba7dbfc49ed --- /dev/null +++ b/Documentation/trace/coresight.txt @@ -0,0 +1,299 @@ + Coresight - HW Assisted Tracing on ARM + ====================================== + + Author: Mathieu Poirier <mathieu.poirier@linaro.org> + Date: September 11th, 2014 + +Introduction +------------ + +Coresight is an umbrella of technologies allowing for the debugging of ARM +based SoC. It includes solutions for JTAG and HW assisted tracing. This +document is concerned with the latter. + +HW assisted tracing is becoming increasingly useful when dealing with systems +that have many SoCs and other components like GPU and DMA engines. ARM has +developed a HW assisted tracing solution by means of different components, each +being added to a design at systhesis time to cater to specific tracing needs. +Compoments are generally categorised as source, link and sinks and are +(usually) discovered using the AMBA bus. + +"Sources" generate a compressed stream representing the processor instruction +path based on tracing scenarios as configured by users. From there the stream +flows through the coresight system (via ATB bus) using links that are connecting +the emanating source to a sink(s). Sinks serve as endpoints to the coresight +implementation, either storing the compressed stream in a memory buffer or +creating an interface to the outside world where data can be transferred to a +host without fear of filling up the onboard coresight memory buffer. + +At typical coresight system would look like this: + + ***************************************************************** + **************************** AMBA AXI ****************************===|| + ***************************************************************** || + ^ ^ | || + | | * ** + 0000000 ::::: 0000000 ::::: ::::: @@@@@@@ |||||||||||| + 0 CPU 0<-->: C : 0 CPU 0<-->: C : : C : @ STM @ || System || + |->0000000 : T : |->0000000 : T : : T :<--->@@@@@ || Memory || + | #######<-->: I : | #######<-->: I : : I : @@@<-| |||||||||||| + | # ETM # ::::: | # PTM # ::::: ::::: @ | + | ##### ^ ^ | ##### ^ ! ^ ! . | ||||||||| + | |->### | ! | |->### | ! | ! . | || DAP || + | | # | ! | | # | ! | ! . | ||||||||| + | | . | ! | | . | ! | ! . | | | + | | . | ! | | . | ! | ! . | | * + | | . | ! | | . | ! | ! . | | SWD/ + | | . | ! | | . | ! | ! . | | JTAG + *****************************************************************<-| + *************************** AMBA Debug ABP ************************ + ***************************************************************** + | . ! . ! ! . | + | . * . * * . | + ***************************************************************** + ******************** Cross Trigger Matrix (CTM) ******************* + ***************************************************************** + | . ^ . . | + | * ! * * | + ***************************************************************** + ****************** AMBA Advanced Trace Bus (ATB) ****************** + ***************************************************************** + | ! =============== | + | * ===== F =====<---------| + | ::::::::: ==== U ==== + |-->:: CTI ::<!! === N === + | ::::::::: ! == N == + | ^ * == E == + | ! &&&&&&&&& IIIIIII == L == + |------>&& ETB &&<......II I ======= + | ! &&&&&&&&& II I . + | ! I I . + | ! I REP I<.......... + | ! I I + | !!>&&&&&&&&& II I *Source: ARM ltd. + |------>& TPIU &<......II I DAP = Debug Access Port + &&&&&&&&& IIIIIII ETM = Embedded Trace Macrocell + ; PTM = Program Trace Macrocell + ; CTI = Cross Trigger Interface + * ETB = Embedded Trace Buffer + To trace port TPIU= Trace Port Interface Unit + SWD = Serial Wire Debug + +While on target configuration of the components is done via the ABP bus, +all trace data are carried out-of-band on the ATB bus. The CTM provides +a way to aggregate and distribute signals between CoreSight components. + +The coresight framework provides a central point to represent, configure and +manage coresight devices on a platform. This first implementation centers on +the basic tracing functionality, enabling components such ETM/PTM, funnel, +replicator, TMC, TPIU and ETB. Future work will enable more +intricate IP blocks such as STM and CTI. + + +Acronyms and Classification +--------------------------- + +Acronyms: + +PTM: Program Trace Macrocell +ETM: Embedded Trace Macrocell +STM: System trace Macrocell +ETB: Embedded Trace Buffer +ITM: Instrumentation Trace Macrocell +TPIU: Trace Port Interface Unit +TMC-ETR: Trace Memory Controller, configured as Embedded Trace Router +TMC-ETF: Trace Memory Controller, configured as Embedded Trace FIFO +CTI: Cross Trigger Interface + +Classification: + +Source: + ETMv3.x ETMv4, PTMv1.0, PTMv1.1, STM, STM500, ITM +Link: + Funnel, replicator (intelligent or not), TMC-ETR +Sinks: + ETBv1.0, ETB1.1, TPIU, TMC-ETF +Misc: + CTI + + +Device Tree Bindings +---------------------- + +See Documentation/devicetree/bindings/arm/coresight.txt for details. + +As of this writing drivers for ITM, STMs and CTIs are not provided but are +expected to be added as the solution matures. + + +Framework and implementation +---------------------------- + +The coresight framework provides a central point to represent, configure and +manage coresight devices on a platform. Any coresight compliant device can +register with the framework for as long as they use the right APIs: + +struct coresight_device *coresight_register(struct coresight_desc *desc); +void coresight_unregister(struct coresight_device *csdev); + +The registering function is taking a "struct coresight_device *csdev" and +register the device with the core framework. The unregister function takes +a reference to a "strut coresight_device", obtained at registration time. + +If everything goes well during the registration process the new devices will +show up under /sys/bus/coresight/devices, as showns here for a TC2 platform: + +root:~# ls /sys/bus/coresight/devices/ +replicator 20030000.tpiu 2201c000.ptm 2203c000.etm 2203e000.etm +20010000.etb 20040000.funnel 2201d000.ptm 2203d000.etm +root:~# + +The functions take a "struct coresight_device", which looks like this: + +struct coresight_desc { + enum coresight_dev_type type; + struct coresight_dev_subtype subtype; + const struct coresight_ops *ops; + struct coresight_platform_data *pdata; + struct device *dev; + const struct attribute_group **groups; +}; + + +The "coresight_dev_type" identifies what the device is, i.e, source link or +sink while the "coresight_dev_subtype" will characterise that type further. + +The "struct coresight_ops" is mandatory and will tell the framework how to +perform base operations related to the components, each component having +a different set of requirement. For that "struct coresight_ops_sink", +"struct coresight_ops_link" and "struct coresight_ops_source" have been +provided. + +The next field, "struct coresight_platform_data *pdata" is acquired by calling +"of_get_coresight_platform_data()", as part of the driver's _probe routine and +"struct device *dev" gets the device reference embedded in the "amba_device": + +static int etm_probe(struct amba_device *adev, const struct amba_id *id) +{ + ... + ... + drvdata->dev = &adev->dev; + ... +} + +Specific class of device (source, link, or sink) have generic operations +that can be performed on them (see "struct coresight_ops"). The +"**groups" is a list of sysfs entries pertaining to operations +specific to that component only. "Implementation defined" customisations are +expected to be accessed and controlled using those entries. + +Last but not least, "struct module *owner" is expected to be set to reflect +the information carried in "THIS_MODULE". + +How to use +---------- + +Before trace collection can start, a coresight sink needs to be identify. +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: + +root:/sys/bus/coresight/devices# ls +replicator 20030000.tpiu 2201c000.ptm 2203c000.etm 2203e000.etm +20010000.etb 20040000.funnel 2201d000.ptm 2203d000.etm +root:/sys/bus/coresight/devices# ls 20010000.etb +enable_sink status trigger_cntr +root:/sys/bus/coresight/devices# echo 1 > 20010000.etb/enable_sink +root:/sys/bus/coresight/devices# cat 20010000.etb/enable_sink +1 +root:/sys/bus/coresight/devices# + +At boot time the current etm3x driver will configure the first address +comparator with "_stext" and "_etext", essentially tracing any instruction +that falls within that range. As such "enabling" a source will immediately +trigger a trace capture: + +root:/sys/bus/coresight/devices# echo 1 > 2201c000.ptm/enable_source +root:/sys/bus/coresight/devices# cat 2201c000.ptm/enable_source +1 +root:/sys/bus/coresight/devices# cat 20010000.etb/status +Depth: 0x2000 +Status: 0x1 +RAM read ptr: 0x0 +RAM wrt ptr: 0x19d3 <----- The write pointer is moving +Trigger cnt: 0x0 +Control: 0x1 +Flush status: 0x0 +Flush ctrl: 0x2001 +root:/sys/bus/coresight/devices# + +Trace collection is stopped the same way: + +root:/sys/bus/coresight/devices# echo 0 > 2201c000.ptm/enable_source +root:/sys/bus/coresight/devices# + +The content of the ETB buffer can be harvested directly from /dev: + +root:/sys/bus/coresight/devices# dd if=/dev/20010000.etb \ +of=~/cstrace.bin + +64+0 records in +64+0 records out +32768 bytes (33 kB) copied, 0.00125258 s, 26.2 MB/s +root:/sys/bus/coresight/devices# + +The file cstrace.bin can be decompressed using "ptm2human", DS-5 or Trace32. + +Following is a DS-5 output of an experimental loop that increments a variable up +to a certain value. The example is simple and yet provides a glimpse of the +wealth of possibilities that coresight provides. + +Info Tracing enabled +Instruction 106378866 0x8026B53C E52DE004 false PUSH {lr} +Instruction 0 0x8026B540 E24DD00C false SUB sp,sp,#0xc +Instruction 0 0x8026B544 E3A03000 false MOV r3,#0 +Instruction 0 0x8026B548 E58D3004 false STR r3,[sp,#4] +Instruction 0 0x8026B54C E59D3004 false LDR r3,[sp,#4] +Instruction 0 0x8026B550 E3530004 false CMP r3,#4 +Instruction 0 0x8026B554 E2833001 false ADD r3,r3,#1 +Instruction 0 0x8026B558 E58D3004 false STR r3,[sp,#4] +Instruction 0 0x8026B55C DAFFFFFA true BLE {pc}-0x10 ; 0x8026b54c +Timestamp Timestamp: 17106715833 +Instruction 319 0x8026B54C E59D3004 false LDR r3,[sp,#4] +Instruction 0 0x8026B550 E3530004 false CMP r3,#4 +Instruction 0 0x8026B554 E2833001 false ADD r3,r3,#1 +Instruction 0 0x8026B558 E58D3004 false STR r3,[sp,#4] +Instruction 0 0x8026B55C DAFFFFFA true BLE {pc}-0x10 ; 0x8026b54c +Instruction 9 0x8026B54C E59D3004 false LDR r3,[sp,#4] +Instruction 0 0x8026B550 E3530004 false CMP r3,#4 +Instruction 0 0x8026B554 E2833001 false ADD r3,r3,#1 +Instruction 0 0x8026B558 E58D3004 false STR r3,[sp,#4] +Instruction 0 0x8026B55C DAFFFFFA true BLE {pc}-0x10 ; 0x8026b54c +Instruction 7 0x8026B54C E59D3004 false LDR r3,[sp,#4] +Instruction 0 0x8026B550 E3530004 false CMP r3,#4 +Instruction 0 0x8026B554 E2833001 false ADD r3,r3,#1 +Instruction 0 0x8026B558 E58D3004 false STR r3,[sp,#4] +Instruction 0 0x8026B55C DAFFFFFA true BLE {pc}-0x10 ; 0x8026b54c +Instruction 7 0x8026B54C E59D3004 false LDR r3,[sp,#4] +Instruction 0 0x8026B550 E3530004 false CMP r3,#4 +Instruction 0 0x8026B554 E2833001 false ADD r3,r3,#1 +Instruction 0 0x8026B558 E58D3004 false STR r3,[sp,#4] +Instruction 0 0x8026B55C DAFFFFFA true BLE {pc}-0x10 ; 0x8026b54c +Instruction 10 0x8026B54C E59D3004 false LDR r3,[sp,#4] +Instruction 0 0x8026B550 E3530004 false CMP r3,#4 +Instruction 0 0x8026B554 E2833001 false ADD r3,r3,#1 +Instruction 0 0x8026B558 E58D3004 false STR r3,[sp,#4] +Instruction 0 0x8026B55C DAFFFFFA true BLE {pc}-0x10 ; 0x8026b54c +Instruction 6 0x8026B560 EE1D3F30 false MRC p15,#0x0,r3,c13,c0,#1 +Instruction 0 0x8026B564 E1A0100D false MOV r1,sp +Instruction 0 0x8026B568 E3C12D7F false BIC r2,r1,#0x1fc0 +Instruction 0 0x8026B56C E3C2203F false BIC r2,r2,#0x3f +Instruction 0 0x8026B570 E59D1004 false LDR r1,[sp,#4] +Instruction 0 0x8026B574 E59F0010 false LDR r0,[pc,#16] ; [0x8026B58C] = 0x80550368 +Instruction 0 0x8026B578 E592200C false LDR r2,[r2,#0xc] +Instruction 0 0x8026B57C E59221D0 false LDR r2,[r2,#0x1d0] +Instruction 0 0x8026B580 EB07A4CF true BL {pc}+0x1e9344 ; 0x804548c4 +Info Tracing enabled +Instruction 13570831 0x8026B584 E28DD00C false ADD sp,sp,#0xc +Instruction 0 0x8026B588 E8BD8000 true LDM sp!,{pc} +Timestamp Timestamp: 17107041535 |