Messages in this thread | | | Date | Thu, 20 Oct 2022 17:03:47 +0100 | Subject | Re: [Question] Question about supporting sysreg only CoreSight ETMv4.4 on ACPI machines | From | Suzuki K Poulose <> |
| |
Hi
On 19/10/2022 03:04, Xiongfeng Wang wrote: > Hi, Suzuki, Anshuman > > On 2022/10/18 17:18, Suzuki Kuruppassery Poulose wrote: >> Hi, >> >> Cc: Anshuman >> >> On 18/10/2022 03:04, Xiongfeng Wang wrote: >>> Hi, Suzuki >>> >>> We are testing CoreSight ETMv4.4 and TRBE recently. ETMv4.4 obsoletes memory >>> mapped access to ETM and mandates the system registers. The following commit add >>> driver for sysreg only devices, but it only support device tree. >>> commit 5214b563588e8414193bd7a174c52350256942a6 >>> coresight: etm4x: Add support for sysreg only devices >>> >>> ACPI machine can use 'ARMHC500' to report a ETM4x device. But the corresponding >>> driver is etm4x_amba_driver. It needs memory resouces and doesn't support sysreg >>> only device. >> >> That is true. Unfortunately, supporting this requires us to move away from the >> AMBA framework (at least) for ETM4x devices. This is currently >> developed by Anshuman. We can share it as soon as this is complete. > > Thanks a lot. Really appreciate ! > By the way, do we have plan to add ACPI support for TRBE driver? ACPI 6.5 add a
Yes, this is again in our pipeline. But, without the ETE support, TRBE is literally unusable. So, this will follow the ETE/ETMv4 sysreg ACPI support.
> field 'TRBE Interrupt' in GICC Structure. In the beginning, I plan to add a > platform device when got this IRQ, just like what SPE does in the following commit > commit d24a0c7099b32b6981d7f126c45348e381718350 > arm_pmu: acpi: spe: Add initial MADT/SPE probing
> But it seems that TRBE still needs _DSD method to report the links(input port > and output port). Do you have some other advices? Thanks a lot.
TRBE doesn't need to specify the input/output ports. It is a per-CPU sink and the TRBE driver registers it as such for each CPU that it probes.
Suzuki
| |