Re: [PATCH v7 05/15] dt-bindings: arm: Adds CoreSight CTI hardware definitions.

On Tue, Jan 7, 2020 at 10:11 AM Mike Leach mike.leach@linaro.org wrote:

Hi Rob,

Thanks for the feedback.

On Fri, 3 Jan 2020 at 22:24, Rob Herring robh@kernel.org wrote:

...

On Mon, Dec 30, 2019 at 04:41:37PM +0000, Mike Leach wrote:

...

Adds new coresight-cti.yaml file describing the bindings required to define CTI in the device trees.

Adds an include file to dt-bindings/arm to define constants describing common signal functionality used in CoreSight and generic usage.

What's going on with the message threading in this series?

Not entirely sure what is expected here.

TL;DR: what git-send-email defaults to.

Each message should set 'in-reply-to' to the 1st message.

...

...

Signed-off-by: Mike Leach mike.leach@linaro.org Reviewed-by: Mathieu Poirier mathieu.poirier@linaro.org Reviewed-by: Suzuki K Poulose suzuki.poulose@arm.com

---

.../bindings/arm/coresight-cti.yaml | 326 ++++++++++++++++++ .../devicetree/bindings/arm/coresight.txt | 7 + MAINTAINERS | 2 + include/dt-bindings/arm/coresight-cti-dt.h | 37 ++ 4 files changed, 372 insertions(+) create mode 100644 Documentation/devicetree/bindings/arm/coresight-cti.yaml create mode 100644 include/dt-bindings/arm/coresight-cti-dt.h

diff --git a/Documentation/devicetree/bindings/arm/coresight-cti.yaml b/Documentation/devicetree/bindings/arm/coresight-cti.yaml new file mode 100644 index 000000000000..e4d28cee5dfd --- /dev/null +++ b/Documentation/devicetree/bindings/arm/coresight-cti.yaml @@ -0,0 +1,326 @@ +# SPDX-License-Identifier: GPL-2.0-only or BSD-2-Clause +# Copyright 2019 Linaro Ltd. +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/arm/coresight-cti.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml#

+title: ARM Coresight Cross Trigger Interface (CTI) device.

+description: |

• The CoreSight Embedded Cross Trigger (ECT) consists of CTI devices connected
• to one or more CoreSight components and/or a CPU, with CTIs interconnected in
• a star topology via the Cross Trigger Matrix (CTM), which is not programmable.
• The ECT components are not part of the trace generation data path and are thus
• not part of the CoreSight graph described in the general CoreSight bindings
• file coresight.txt.
• The CTI component properties define the connections between the individual
• CTI and the components it is directly connected to, consisting of input and
• output hardware trigger signals. CTIs can have a maximum number of input and
• output hardware trigger signals (8 each for v1 CTI, 32 each for v2 CTI). The
• number is defined at design time, the maximum of each defined in the DEVID
• register.
• CTIs are interconnected in a star topology via the CTM, using a number of
• programmable channels, usually 4, but again implementation defined and
• described in the DEVID register. The star topology is not required to be
• described in the bindings as the actual connections are software
• programmable.
• In general the connections between CTI and components via the trigger signals
• are implementation defined, except when the CTI is connected to an ARM v8
• architecture core and optional ETM.
• In this case the ARM v8 architecture defines the required signal connections
• between CTI and the CPU core and ETM if present. In the case of a v8
• architecturally connected CTI an additional compatible string is used to
• indicate this feature (arm,coresight-cti-v8-arch).
• When CTI trigger connection information is unavailable then a minimal driver
• binding can be declared with no explicit trigger signals. This will result
• the driver detecting the maximum available triggers and channels from the
• DEVID register and make them all available for use as a single default
• connection. Any user / client application will require additional information
• on the connections between the CTI and other components for correct operation.
• This information might be found by enabling the Integration Test registers in
• the driver (set CONFIG_CORESIGHT_CTI_INTEGRATION_TEST in Kernel
• configuration). These registers may be used to explore the trigger connections
• between CTI and other CoreSight components.
• Certain triggers between CoreSight devices and the CTI have specific types
• and usages. These can be defined along with the signal indexes with the
• constants defined in <dt-bindings/arm/coresight-cti-dt.h>
• For example a CTI connected to a core will usually have a DBGREQ signal. This
• is defined in the binding as type PE_EDBGREQ. These types will appear in an
• optional array alongside the signal indexes. Omitting types will default all
• signals to GEN_IO.
• Note that some hardware trigger signals can be connected to non-CoreSight
• components (e.g. UART etc) depending on hardware implementation.

+maintainers:

• • Mike Leach mike.leach@linaro.org

+allOf:

• • $ref: /schemas/arm/primecell.yaml#

+# Need a custom select here or 'arm,primecell' will match on lots of nodes +select:

• properties:
• compatible:

•  contains:
  

•    enum:
  

•      - arm,coresight-cti
  

• required:
• • compatible

+properties:

• $nodename:
• pattern: "^cti(@[0-9a-f]+)$"
• compatible:
• oneOf:

•  - items:
  

•    - const: arm,coresight-cti
  

•    - const: arm,primecell
  

•  - items:
  

•    - const: arm,coresight-cti-v8-arch
  

•    - const: arm,coresight-cti
  

•    - const: arm,primecell
  

• reg:
• maxItems: 1
• cpu:
• $ref: /schemas/types.yaml#/definitions/phandle
• description:

•  Handle to cpu this device is associated with. This must appear in the
  

•  base cti node if compatible string arm,coresight-cti-v8-arch is used,
  

•  or may appear in a trig-conns child node when appropriate.
  

• arm,cti-ctm-id:
• $ref: /schemas/types.yaml#/definitions/uint32
• description:

•  Defines the CTM this CTI is connected to, in large systems with multiple
  

•  separate CTI/CTM nets. Typically multi-socket systems where the CTM is
  

•  propagated between sockets.
  

• arm,cs-dev-assoc:
• $ref: /schemas/types.yaml#/definitions/phandle
• description:

•  defines a phandle reference to an associated CoreSight trace device.
  

•  When the associated trace device is enabled, then the respective CTI
  

•  will be enabled. Use in a trig-conns node, or in CTI base node when
  

•  compatible string arm,coresight-cti-v8-arch used. If the associated
  

•  device has not been registered then the node name will be stored as
  

•  the connection name for later resolution. If the associated device is
  

•  not a CoreSight device or not registered then the node name will remain
  

•  the connection name and automatic enabling will not occur.
  

+patternProperties:

• '^trig-conns@([0-9]+)$':
• type: object
• description:

•  A trigger connections child node which describes the trigger signals
  

•  between this CTI and another hardware device. This device may be a CPU,
  

•  CoreSight device, any other hardware device or simple external IO lines.
  

•  The connection may have both input and output triggers, or only one or the
  

•  other.
  

• properties:

•  arm,trig-in-sigs:
  

•    allOf:
  

•      - $ref: /schemas/types.yaml#/definitions/uint32-array
  

•    minItems: 1
  

•    maxItems: 32
  

•    description:
  

•      List of CTI trigger in signal numbers in use by a trig-conns node.
  

•  arm,trig-in-types:
  

•    allOf:
  

•      - $ref: /schemas/types.yaml#/definitions/uint32-array
  

•    minItems: 1
  

•    maxItems: 32
  

•    description:
  

•      List of constants representing the types for the CTI trigger in
  

•      signals. Types in this array match to the corresponding signal in the
  

•      arm,trig-in-sigs array. If the -types array is smaller, or omitted
  

•      completely, then the types will default to GEN_IO.
  

•  arm,trig-out-sigs:
  

•    allOf:
  

•      - $ref: /schemas/types.yaml#/definitions/uint32-array
  

•    minItems: 1
  

•    maxItems: 32
  

•    description:
  

•      List of CTI trigger out signal numbers in use by a trig-conns node.
  

•  arm,trig-out-types:
  

•    allOf:
  

•      - $ref: /schemas/types.yaml#/definitions/uint32-array
  

•    minItems: 1
  

•    maxItems: 32
  

•    description:
  

•      List of constants representing the types for the CTI trigger out
  

•      signals. Types in this array match to the corresponding signal
  

•      in the arm,trig-out-sigs array. If the "-types" array is smaller,
  

•      or omitted completely, then the types will default to GEN_IO.
  

•  arm,trig-filters:
  

•    allOf:
  

•      - $ref: /schemas/types.yaml#/definitions/uint32-array
  

•    minItems: 1
  

•    maxItems: 32
  

•    description:
  

•      List of CTI trigger out signals that will be blocked from becoming
  

•      active, unless filtering is disabled on the driver.
  

•  arm,trig-conn-name:
  

•    allOf:
  

•      - $ref: /schemas/types.yaml#/definitions/string
  

•    description:
  

•      Defines a connection name that will be displayed, if the cpu or
  

•      arm,cs-dev-assoc properties are not being used in this connection.
  

•      Principle use for CTI that are connected to non-CoreSight devices, or
  

•      external IO.
  

• anyOf:

•  - required:
  

•    - arm,trig-in-sigs
  

•  - required:
  

•    - arm,trig-out-sigs
  

• oneOf:

•  - required:
  

•    - arm,trig-conn-name
  

•  - required:
  

•    - cpu
  

•  - required:
  

•    - arm,cs-dev-assoc
  

• required:

•  - reg
  

You need 'reg' defined as a property too along with any constraints.

OK - will do.

...

You also need #size-cells and #address-cells in the parent. And are they required?

Size cells/ address cells can be defined and limited to appropriate values.

However they are only required if the binding defines optional child nodes per the patternProperties: '^trig-conns@([0-9]+)$': pattern. I have not been able to find a form a .yaml that can encode this requirement. if ( element matches "trig-conns") then required (#size-cells, #address-cells.)

I think there's not yet a way until something like this is accepted:

https://github.com/json-schema-org/json-schema-spec/issues/117

You could express it if you knew there's always at least 'trig-conns@0' or some other unit-address. But if you don't know what unit-addresses you'll have, then you can't.

What I do find is that if a trig-conns element has been defined, then the binding will not compile correctly without #size-cells and #address-cells.

Right, dtc checks this already, so not too important that the schema be able to.

Rob