Hi,

On 4/21/26 11:30, Yeoreum Yun wrote:

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Hi Mike,

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Hi,

This register [bit 31] indicates if a single shot comparator has matched. So read-back provides information to the user post run to determine which if any of the comparators set in this way has actually matched.

Okay. so after disable sysfs session, to check former session check whether comprator has matched.

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Moreover, the specification states "Software must reset this bit to 0 to re-enable single-shot control" and "Reset state is unknown. STATUS must be written to set an initial state...."

Therefore this register must be written as part of any configuration so should be available in the drvdata->config for both read and write,

But I don't think this is the reason for locate ss_status into "config" since its write purpose is not to configure but the "clear" former bit. That's why I think it's enough to clear when the new sysfs session starts.

IOW, I think it's better to remove ss_status from configfs item and

• add field ss_cmp in etm4_cpas
• add another field ss_status under "etm4_drvdata" to show "PENDING and STATUS" bits to sysfs after finishing session.

Is is valid for you?

No. Why two different locations for a single register read? If I have the ETMv4 hardware manual I am going to look for a something that is recognizable as being related to the single shot comparator status register(s).

So in sysfs I would expect to see all the bits from the register, displayed, without masking off the STATUS and PENDING bits as happens now.

In the code I would expect to see a single location with a sensible name - ss_cmp doesn't really correlate terribly well with TRCSSCSR. If you do not like the original ss_status, then ss_cmp_status may actually be better, ss_cmp could be either the ss comparator status or control register.

Regards

Mike

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-- Sincerely, Yeoreum Yun

-- Sincerely, Yeoreum Yun