Re: [PATCH v6 0/5] Coresight: Add Coresight TMC Control Unit driver

[Jie Gan <quic_jiegan@quicinc.com>]

On 10/9/2024 7:24 PM, Jie Gan wrote:
> The Coresight TMC Control Unit(CTCU) device hosts miscellaneous configuration
> registers to control various features related to TMC ETR device.
> 
> The CTCU device works as a helper device physically connected to the TMC ETR device.
> ---------------------------------------------------------
>               |ETR0|             |ETR1|
>                . \                 / .
>                .  \               /  .
>                .   \             /   .
>                .    \           /    .
> ---------------------------------------------------
> ETR0ATID0-ETR0ATID3     CTCU    ETR1ATID0-ETR1ATID3
> ---------------------------------------------------
> Each ETR has four ATID registers with 128 bits long in total.
> e.g. ETR0ATID0-ETR0ATID3 registers are used by ETR0 device.
> 
> Based on the trace id which is programed in CTCU ATID register of
> specific ETR, trace data with that trace id can get into ETR's buffer
> while other trace data gets ignored. The number of CTCU ATID registers
> depends on the number of defined TMC ETR devices. For example, two TMC
> ETR devices need eight ATID registers. ETR0 with ETR0ATID0-ETR0ATID3
> and ETR1 with ETR1ATID0-ETRATID3.
> 
> The significant challenge in enabling the data filter function is how
> to collect the trace ID of the source device. The introduction of
> trace_id callback function addresses this challenge. The callback function
> collects trace ID of the device and return it back. The trace ID will be
> stored in the structure called cs_sink_data and transmitted to helper
> and sink devices.
> 
> The cs_sink_data structure is created to address how to transmit
> parameters needs by coresight_enable_path/coresight_disbale_path
> functions.
> 
> Here is an example of the struct cs_sink_data:
> struct cs_sink_data {
>          struct perf_output_handle  *handle; //used by perf mode
>          struct coresight_device    *sink;   //used to retrieve atid_offset
>          u32                        traceid; //traceid needed by CTCU
> };
> 
> The atid_offset mentioned before is the offset to ATID register in CTCU
> device.
> 
> Enabling the source device will configure one bit in the ATID register based
> on its trace ID.
> Disabling the source devices will reset the bit in the AITD register
> based on its trace ID.
> 
[...]

Kindly remainder, Please help to review the patch series.

Thanks,
Jie