On 03/20/2019 06:49 PM, 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.
As a prepartion for the ACPI support, we merge the driver for dynamic
and non-programmable replicators. 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 v5.1-rc1
Tested on a Juno-r0 board with ACPI bindings patch (Patch 26/25) 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.
[0] ACPI Device Graphs using _DSD (Not available online yet, approved but
awaiting publish and eventually should be linked at).
https://uefi.org/sites/default/files/resources/_DSD-implementation-guide-toplevel-1_1.htm
[1] https://developer.arm.com/docs/den0067/latest/acpi-for-coresighttm-10-platform-design-document
[2] https://github.com/tianocore/edk2-platforms.git
The kernel patches are also available here :
git://linux-arm.org/linux-skp.git coresight-acpi/v1
Kind regards
Suzuki
