Hi Suzuki, On 7/26/2023 9:59 AM, Suzuki K Poulose wrote: > On 10/07/2023 07:24, Anshuman Khandual wrote: >> CoreSight ETM4x devices could be accessed either via MMIO (handled via >> amba_driver) or CPU system instructions (handled via platform driver). >> But >> this has the following issues : >> >> - Each new CPU comes up with its own PID and thus we need to keep on >> adding the "known" PIDs to get it working with AMBA driver. While >> the ETM4 architecture (and CoreSight architecture) defines way to >> identify a device as ETM4. Thus older kernels won't be able to >> "discover" a newer CPU, unless we add the PIDs. >> >> - With ACPI, the ETM4x devices have the same HID to identify the >> device >> irrespective of the mode of access. This creates a problem where two >> different drivers (both AMBA based driver and platform driver) would >> hook into the "HID" and could conflict. e.g., if AMBA driver gets >> hold of a non-MMIO device, the probe fails. If we have single driver >> hooked into the given "HID", we could handle them seamlessly, >> irrespective of the mode of access. >> >> - CoreSight is heavily dependent on the runtime power management. With >> ACPI, amba_driver doesn't get us anywhere with handling the power >> and thus one need to always turn the power ON to use them. Moving to >> platform driver gives us the power management for free. >> >> Due to all of the above, we are moving ACPI MMIO based etm4x devices >> to be >> supported via tha platform driver. The series makes the existing platform >> driver generic to handle both type of the access modes. Although existing >> AMBA driver would still continue to support DT based etm4x MMIO devices. >> Although some problems still remain, such as manually adding PIDs for all >> new AMBA DT based devices. >> >> The series applies on 6.5-rc1. >> >> Changes in V6: >> >> - Rebased on 6.5-rc1 >> > > I have queued this version for v6.6, should appear on coresight/next soon. > > Suzuki Is there anyway to queue this for 6.5? Or has that ship sailed? Thanks, Steve C.
