Some HW has static trace id which cannot be changed via software programming. For this case, configure the trace id in device tree with "arm,static-trace-id = <xxx>", and call coresight_trace_id_get_static_system_id with the trace id value in device probe function. The id will be reserved for the HW all the time if the device is probed. Changes since V6: 1. Add code to handle a case where the preferred_id is not valid when use static id. 2. Returen busy when static id is not freed. Changes since V5: 1. Remove the warn for staic id not available. 2. Drop the system_id if registering the coresight device fails. 3. Return busy when static id is not available in dummy driver. Changes since V4: 1. Use fwnode_property_read_u32 in fwnode_property_read_u32. 2. Update date and version in sysfs-bus-coresight-devices-dummy-source Changes since V3: 1. Adda new API function int coresight_trace_id_get_system_static_id(int trace_id). 2. Use the term "static trace id" for these devices where the hardware sets a non-programmable trace ID. Changes since V2: 1. Change "trace-id" to "arm,trace-id". 2. Add trace id flag for getting preferred id or ODD id. Changes since V1: 1. Add argument to coresight_trace_id_get_system_id for preferred id instead of adding new function coresight_trace_id_reserve_system_id. 2. Add constraint to trace-id in dt-binding file. Mao Jinlong (3): dt-bindings: arm: Add arm,static-trace-id for coresight dummy source coresight: Add support to get static id for system trace sources coresight: dummy: Add static trace id support for dummy source .../sysfs-bus-coresight-devices-dummy-source | 15 ++++ .../arm/arm,coresight-dummy-source.yaml | 6 ++ drivers/hwtracing/coresight/coresight-dummy.c | 81 ++++++++++++++++--- .../hwtracing/coresight/coresight-platform.c | 6 ++ .../hwtracing/coresight/coresight-trace-id.c | 43 +++++++--- .../hwtracing/coresight/coresight-trace-id.h | 9 +++ include/linux/coresight.h | 1 + 7 files changed, 140 insertions(+), 21 deletions(-) create mode 100644 Documentation/ABI/testing/sysfs-bus-coresight-devices-dummy-source -- 2.17.1
