Good day, On Tue, May 28, 2019 at 01:19:24PM +0800, Leo Yan wrote: > 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
Yes, that is the expected behavior. > > 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) Correct. > > 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 Correct. > > 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. Correct - v2 did not address the new naming convention for devices present under 'event_source', something that was corrected in v3. > Please help confirm for this. Thanks! > > Leo.
