On Tue, May 28, 2019 at 08:51:26AM -0600, Mathieu Poirier wrote: > 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.
Thanks for confirmation, Mathieu.
