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authorMark Brown <broonie@kernel.org>2015-01-09 18:22:45 +0000
committerMark Brown <broonie@kernel.org>2015-01-09 18:22:45 +0000
commit2156eda2aafa0b0f660656246a11d7c2a9947ff9 (patch)
tree81c2fadeadc2f62e3a03c5fe78b41087d2926233 /Documentation
parentbbba26b2fc88c77239ebcd45d7fb669018511dfe (diff)
parent312ccd6ab1510724d298ae6c19177e501d6c1ca0 (diff)
downloadlinux-linaro-stable-2156eda2aafa0b0f660656246a11d7c2a9947ff9.tar.gz
Merge remote-tracking branch 'lsk/v3.10/topic/coresight' into linux-linaro-lsk
Conflicts: arch/arm/include/asm/hardware/coresight.h drivers/Makefile drivers/of/base.c
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/devicetree/bindings/arm/coresight.txt204
-rw-r--r--Documentation/trace/coresight.txt299
2 files changed, 503 insertions, 0 deletions
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