Hi Suzuki, On Wed, May 22, 2019 at 11:34:33AM +0100, Suzuki K Poulose wrote: > This series adds the support for CoreSight devices on ACPI based > platforms. The device connections are encoded as _DSD graph property[0], > with CoreSight specific extensions to indicate the direction of data > flow as described in [1]. Components attached to CPUs are listed > as child devices of the corresponding CPU, removing explicit links > to the CPU like we do in the DT. > > The majority of the series cleans up the driver and prepares the subsystem > for platform agnostic firwmare probing, naming scheme, searching etc. > > We introduce platform independent helpers to parse the platform supplied > information. Thus we rename the platform handling code from: > of_coresight.c => coresight-platform.c > > The CoreSight driver creates shadow devices that appear on the Coresight > bus, in addition to the real devices (e.g, AMBA bus devices). The name > of these devices match the real device. This makes the device name > a bit cryptic for ACPI platform. So this series also introduces a generic > platform agnostic device naming scheme for the shadow Coresight devices. > Towards this we also make changes to the way we lookup devices to resolve > the connections, as we can't use the names to identify the devices. So, > we use the "fwnode_handle" of the real device for the device lookups. > Towards that we clean up the drivers to keep track of the "CoreSight" > device rather than the "real" device. However, all real operations, > like DMA allocation, Power management etc. must be performed on > the real device which is the parent of the shadow device. > > Finally we add the support for parsing the ACPI platform data. The power > management support is missing in the ACPI (and this is not specific to > CoreSight). The firmware must ensure that the respective power domains > are turned on. > > Applies on v5.2-rc1 > > Tested on a Juno-r0 board with ACPI bindings patch (Patch 31/30) added on > top of [2]. You would need to make sure that the debug power domain is > turned on before the Linux kernel boots. (e.g, connect the DS-5 to the > Juno board while at UEFI). arm32 code is only compile tested.
After I applied this patch set, I found all device names under '/sys/bus/event_source/devices/cs_etm/sinks/' have been changed as below on my DB410c board: # ls /sys/bus/event_source/devices/cs_etm/sinks/ tmc_etf0 tmc_etr0 tpiu0 This leads to below command failure when open PMU device: # perf record -e cs_etm/@826000.etr/ --per-thread uname failed to set sink "826000.etr" on event cs_etm/@826000.etr/ with 2 (No such file or directory) I must use below command so that perf can match string with the device name under '/sys/bus/event_source/devices/cs_etm/sinks/': # perf record -e cs_etm/@tmc_etr0/ --per-thread uname Seems to me, this is an unexpected change and when I worked on the patch set v2, IIRC that version still can use '826000.etr' to open PMU device. Please help confirm for this. Thanks! Leo.
