Re: [PATCH v3 1/5] coresight: etm4x: introduce struct etm4_caps

[Jie Gan <jie.gan@oss.qualcomm.com>]

Hi Yeoreum,

On 4/13/2026 1:55 AM, Yeoreum Yun wrote:
> introduce struct etm4_caps to describe ETMv4 capabilities
> and move capabilities information into it.
> 
> Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
> ---
>   .../coresight/coresight-etm4x-core.c          | 234 +++++++++---------
>   .../coresight/coresight-etm4x-sysfs.c         | 190 ++++++++------
>   drivers/hwtracing/coresight/coresight-etm4x.h | 175 ++++++-------
>   3 files changed, 327 insertions(+), 272 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> index d565a73f0042..6443f3717b37 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c

<...>

> +/**
> + * struct etmv4_caps - specifics ETM capabilities
> + * @nr_pe:	The number of processing entity available for tracing.
> + * @nr_pe_cmp:	The number of processing entity comparator inputs that are
> + *		available for tracing.
> + * @nr_addr_cmp:Number of pairs of address comparators available
> + *		as found in ETMIDR4 0-3.
> + * @nr_cntr:    Number of counters as found in ETMIDR5 bit 28-30.
> + * @nr_ext_inp: Number of external input.
> + * @numcidc:	Number of contextID comparators.

@numextinsel:

> + * @numvmidc:	Number of VMID comparators.
> + * @nrseqstate: The number of sequencer states that are implemented.
> + * @nr_event:	Indicates how many events the trace unit support.
> + * @nr_resource:The number of resource selection pairs available for tracing.
> + * @nr_ss_cmp:	Number of single-shot comparator controls that are available.
> + * @trcid_size: Indicates the trace ID width.
> + * @ts_size:	Global timestamp size field.
> + * @ctxid_size:	Size of the context ID field to consider.
> + * @vmid_size:	Size of the VM ID comparator to consider.
> + * @ccsize:	Indicates the size of the cycle counter in bits.
> + * @ccitmin:	minimum value that can be programmed in
> + * @s_ex_level:	In secure state, indicates whether instruction tracing is
> + *		supported for the corresponding Exception level.
> + * @ns_ex_level:In non-secure state, indicates whether instruction tracing is
> + *		supported for the corresponding Exception level.
> + * @q_support:	Q element support characteristics.
> + * @os_lock_model: OSLock model.
> + * @instrp0:	Tracing of load and store instructions
> + *		as P0 elements is supported.
> + * @q_filt:	Q element filtering support, if Q elements are supported.
> + * @trcbb:	Indicates if the trace unit supports branch broadcast tracing.
> + * @trccond:	If the trace unit supports conditional
> + *		instruction tracing.
> + * @retstack:	Indicates if the implementation supports a return stack.
> + * @trccci:	Indicates if the trace unit supports cycle counting
> + *		for instruction.
> + * @trc_error:	Whether a trace unit can trace a system
> + *		error exception.
> + * @syncpr:	Indicates if an implementation has a fixed
> + *		synchronization period.
> + * @stallctl:	If functionality that prevents trace unit buffer overflows
> + *		is available.
> + * @sysstall:	Does the system support stall control of the PE?
> + * @nooverflow:	Indicate if overflow prevention is supported.
> + * @atbtrig:	If the implementation can support ATB triggers
> + * @lpoverride:	If the implementation can support low-power state over.
> + * @skip_power_up: Indicates if an implementation can skip powering up
> + *		   the trace unit.
> + */
> +struct etmv4_caps {
> +	u8	nr_pe;
> +	u8	nr_pe_cmp;
> +	u8	nr_addr_cmp;
> +	u8	nr_cntr;
> +	u8	nr_ext_inp;
> +	u8	numcidc;
> +	u8	numextinsel;

missed kernel_doc.

Thanks,
Jie

> +	u8	numvmidc;
> +	u8	nrseqstate;
> +	u8	nr_event;
> +	u8	nr_resource;
> +	u8	nr_ss_cmp;
> +	u8	trcid_size;
> +	u8	ts_size;
> +	u8	ctxid_size;
> +	u8	vmid_size;
> +	u8	ccsize;
> +	u16	ccitmin;
> +	u8	s_ex_level;
> +	u8	ns_ex_level;
> +	u8	q_support;
> +	u8	os_lock_model;
> +	bool	instrp0 : 1;
> +	bool	q_filt : 1;
> +	bool	trcbb : 1;
> +	bool	trccond : 1;
> +	bool	retstack : 1;
> +	bool	trccci : 1;
> +	bool	trc_error : 1;
> +	bool	syncpr : 1;
> +	bool	stallctl : 1;
> +	bool	sysstall : 1;
> +	bool	nooverflow : 1;
> +	bool	atbtrig : 1;
> +	bool	lpoverride : 1;
> +	bool	skip_power_up : 1;
> +};
> +
>   /**
>    * struct etmv4_config - configuration information related to an ETMv4
>    * @mode:	Controls various modes supported by this ETM.
> @@ -819,8 +907,8 @@ enum etm_impdef_type {
>    * @cfg:	Controls the tracing options.
>    * @eventctrl0: Controls the tracing of arbitrary events.
>    * @eventctrl1: Controls the behavior of the events that @event_ctrl0 selects.
> - * @stallctl:	If functionality that prevents trace unit buffer overflows
> - *		is available.
> + * @stall_ctrl:	Enables trace unit functionality that prevents trace
> + *		unit buffer overflows.
>    * @ts_ctrl:	Controls the insertion of global timestamps in the
>    *		trace streams.
>    * @syncfreq:	Controls how often trace synchronization requests occur.
> @@ -971,61 +1059,17 @@ struct etmv4_save_state {
>    * @mode:	This tracer's mode, i.e sysFS, Perf or disabled.
>    * @cpu:        The cpu this component is affined to.
>    * @arch:       ETM architecture version.
> - * @nr_pe:	The number of processing entity available for tracing.
> - * @nr_pe_cmp:	The number of processing entity comparator inputs that are
> - *		available for tracing.
> - * @nr_addr_cmp:Number of pairs of address comparators available
> - *		as found in ETMIDR4 0-3.
> - * @nr_cntr:    Number of counters as found in ETMIDR5 bit 28-30.
> - * @nr_ext_inp: Number of external input.
> - * @numcidc:	Number of contextID comparators.
> - * @numvmidc:	Number of VMID comparators.
> - * @nrseqstate: The number of sequencer states that are implemented.
> - * @nr_event:	Indicates how many events the trace unit support.
> - * @nr_resource:The number of resource selection pairs available for tracing.
> - * @nr_ss_cmp:	Number of single-shot comparator controls that are available.
> + * @caps:	ETM capabilities.
>    * @trcid:	value of the current ID for this component.
> - * @trcid_size: Indicates the trace ID width.
> - * @ts_size:	Global timestamp size field.
> - * @ctxid_size:	Size of the context ID field to consider.
> - * @vmid_size:	Size of the VM ID comparator to consider.
> - * @ccsize:	Indicates the size of the cycle counter in bits.
> - * @ccitmin:	minimum value that can be programmed in
> - * @s_ex_level:	In secure state, indicates whether instruction tracing is
> - *		supported for the corresponding Exception level.
> - * @ns_ex_level:In non-secure state, indicates whether instruction tracing is
> - *		supported for the corresponding Exception level.
>    * @sticky_enable: true if ETM base configuration has been done.
>    * @boot_enable:True if we should start tracing at boot time.
>    * @os_unlock:  True if access to management registers is allowed.
> - * @instrp0:	Tracing of load and store instructions
> - *		as P0 elements is supported.
> - * @q_filt:	Q element filtering support, if Q elements are supported.
> - * @trcbb:	Indicates if the trace unit supports branch broadcast tracing.
> - * @trccond:	If the trace unit supports conditional
> - *		instruction tracing.
> - * @retstack:	Indicates if the implementation supports a return stack.
> - * @trccci:	Indicates if the trace unit supports cycle counting
> - *		for instruction.
> - * @q_support:	Q element support characteristics.
> - * @trc_error:	Whether a trace unit can trace a system
> - *		error exception.
> - * @syncpr:	Indicates if an implementation has a fixed
> - *		synchronization period.
> - * @stall_ctrl:	Enables trace unit functionality that prevents trace
> - *		unit buffer overflows.
> - * @sysstall:	Does the system support stall control of the PE?
> - * @nooverflow:	Indicate if overflow prevention is supported.
> - * @atbtrig:	If the implementation can support ATB triggers
> - * @lpoverride:	If the implementation can support low-power state over.
>    * @trfcr:	If the CPU supports FEAT_TRF, value of the TRFCR_ELx that
>    *		allows tracing at all ELs. We don't want to compute this
>    *		at runtime, due to the additional setting of TRFCR_CX when
>    *		in EL2. Otherwise, 0.
>    * @config:	structure holding configuration parameters.
>    * @save_state:	State to be preserved across power loss
> - * @skip_power_up: Indicates if an implementation can skip powering up
> - *		   the trace unit.
>    * @paused:	Indicates if the trace unit is paused.
>    * @arch_features: Bitmap of arch features of etmv4 devices.
>    */
> @@ -1037,46 +1081,11 @@ struct etmv4_drvdata {
>   	raw_spinlock_t			spinlock;
>   	int				cpu;
>   	u8				arch;
> -	u8				nr_pe;
> -	u8				nr_pe_cmp;
> -	u8				nr_addr_cmp;
> -	u8				nr_cntr;
> -	u8				nr_ext_inp;
> -	u8				numcidc;
> -	u8				numextinsel;
> -	u8				numvmidc;
> -	u8				nrseqstate;
> -	u8				nr_event;
> -	u8				nr_resource;
> -	u8				nr_ss_cmp;
> +	struct etmv4_caps		caps;
>   	u8				trcid;
> -	u8				trcid_size;
> -	u8				ts_size;
> -	u8				ctxid_size;
> -	u8				vmid_size;
> -	u8				ccsize;
> -	u16				ccitmin;
> -	u8				s_ex_level;
> -	u8				ns_ex_level;
> -	u8				q_support;
> -	u8				os_lock_model;
>   	bool				sticky_enable : 1;
>   	bool				boot_enable : 1;
>   	bool				os_unlock : 1;
> -	bool				instrp0 : 1;
> -	bool				q_filt : 1;
> -	bool				trcbb : 1;
> -	bool				trccond : 1;
> -	bool				retstack : 1;
> -	bool				trccci : 1;
> -	bool				trc_error : 1;
> -	bool				syncpr : 1;
> -	bool				stallctl : 1;
> -	bool				sysstall : 1;
> -	bool				nooverflow : 1;
> -	bool				atbtrig : 1;
> -	bool				lpoverride : 1;
> -	bool				skip_power_up : 1;
>   	bool				paused : 1;
>   	u64				trfcr;
>   	struct etmv4_config		config;