Re: [PATCH v2 4/5] coresight: etm3x: introduce struct etm_caps

Yeoreum Yun
2026-04-12T15:43:37Z

Hi Jie,

>
>
> On 4/10/2026 3:43 PM, Yeoreum Yun wrote:
> > Introduce struct etm_caps to describe ETMv3 capabilities
> > and move capabilities information into it.
> >
> > Since drvdata->etmccr and drvdata->etmccer are used to check
> > whether it supports fifofull logic and timestamping,
> > remove etmccr and etmccer field from drvdata and add relevant fields
> > in etm_caps structure.
> >
> > Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
> > ---
> > drivers/hwtracing/coresight/coresight-etm.h | 40 +++++++++++--------
> > .../coresight/coresight-etm3x-core.c | 33 ++++++++-------
> > .../coresight/coresight-etm3x-sysfs.c | 14 ++++---
> > 3 files changed, 52 insertions(+), 35 deletions(-)
> >
> > diff --git a/drivers/hwtracing/coresight/coresight-etm.h b/drivers/hwtracing/coresight/coresight-etm.h
> > index 1d753cca2943..6fda26039db8 100644
> > --- a/drivers/hwtracing/coresight/coresight-etm.h
> > +++ b/drivers/hwtracing/coresight/coresight-etm.h
> > @@ -140,6 +140,28 @@
> > ETM_ADD_COMP_0 | \
> > ETM_EVENT_NOT_A)
> > +/**
> > + * struct etmv4_caps - specifics ETM capabilities
> > + * @port_size: port size as reported by ETMCR bit 4-6 and 21.
> > + * @nr_addr_cmp:Number of pairs of address comparators as found in ETMCCR.
> > + * @nr_cntr: Number of counters as found in ETMCCR bit 13-15.
> > + * @nr_ext_inp: Number of external input as found in ETMCCR bit 17-19.
> > + * @nr_ext_out: Number of external output as found in ETMCCR bit 20-22.
> > + * @nr_ctxid_cmp: Number of contextID comparators as found in ETMCCR bit 24-25.
> > + * @fifofull: FIFOFULL logic is present.
> > + * @timestamp: Timestamping is implemented.
> > + */
> > +struct etm_caps {
> > + int port_size;
> > + u8 nr_addr_cmp;
> > + u8 nr_cntr;
> > + u8 nr_ext_inp;
> > + u8 nr_ext_out;
> > + u8 nr_ctxid_cmp;
> > + bool fifofull : 1;
> > + bool timestamp : 1;
> > +};
> > +
> > /**
> > * struct etm_config - configuration information related to an ETM
> > * @mode: controls various modes supported by this ETM/PTM.
> > @@ -212,19 +234,12 @@ struct etm_config {
> > * @csdev: component vitals needed by the framework.
> > * @spinlock: only one at a time pls.
> > * @cpu: the cpu this component is affined to.
> > - * @port_size: port size as reported by ETMCR bit 4-6 and 21.
> > * @arch: ETM/PTM version number.
> > + * @caps: ETM capabilities.
> > * @use_cpu14: true if management registers need to be accessed via CP14.
> > * @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.
> > - * @nr_addr_cmp:Number of pairs of address comparators as found in ETMCCR.
> > - * @nr_cntr: Number of counters as found in ETMCCR bit 13-15.
> > - * @nr_ext_inp: Number of external input as found in ETMCCR bit 17-19.
> > - * @nr_ext_out: Number of external output as found in ETMCCR bit 20-22.
> > - * @nr_ctxid_cmp: Number of contextID comparators as found in ETMCCR bit 24-25.
> > - * @etmccr: value of register ETMCCR.
> > - * @etmccer: value of register ETMCCER.
> > * @traceid: value of the current ID for this component.
> > * @config: structure holding configuration parameters.
> > */
> > @@ -234,19 +249,12 @@ struct etm_drvdata {
> > struct coresight_device *csdev;
> > spinlock_t spinlock;
> > int cpu;
> > - int port_size;
> > u8 arch;
> > + struct etm_caps caps;
> > bool use_cp14;
> > bool sticky_enable;
> > bool boot_enable;
> > bool os_unlock;
> > - u8 nr_addr_cmp;
> > - u8 nr_cntr;
> > - u8 nr_ext_inp;
> > - u8 nr_ext_out;
> > - u8 nr_ctxid_cmp;
> > - u32 etmccr;
> > - u32 etmccer;
> > u32 traceid;
> > struct etm_config config;
> > };
> > diff --git a/drivers/hwtracing/coresight/coresight-etm3x-core.c b/drivers/hwtracing/coresight/coresight-etm3x-core.c
> > index a547a6d2e0bd..b7e977defb1c 100644
> > --- a/drivers/hwtracing/coresight/coresight-etm3x-core.c
> > +++ b/drivers/hwtracing/coresight/coresight-etm3x-core.c
> > @@ -367,6 +367,7 @@ static int etm_enable_hw(struct etm_drvdata *drvdata)
> > {
> > int i, rc;
> > u32 etmcr;
> > + const struct etm_caps *caps = &drvdata->caps;
> > struct etm_config *config = &drvdata->config;
> > struct coresight_device *csdev = drvdata->csdev;
> > @@ -388,7 +389,7 @@ static int etm_enable_hw(struct etm_drvdata *drvdata)
> > etmcr = etm_readl(drvdata, ETMCR);
> > /* Clear setting from a previous run if need be */
> > etmcr &= ~ETM3X_SUPPORTED_OPTIONS;
> > - etmcr |= drvdata->port_size;
> > + etmcr |= caps->port_size;
> > etmcr |= ETMCR_ETM_EN;
> > etm_writel(drvdata, config->ctrl | etmcr, ETMCR);
> > etm_writel(drvdata, config->trigger_event, ETMTRIGGER);
> > @@ -396,11 +397,11 @@ static int etm_enable_hw(struct etm_drvdata *drvdata)
> > etm_writel(drvdata, config->enable_event, ETMTEEVR);
> > etm_writel(drvdata, config->enable_ctrl1, ETMTECR1);
> > etm_writel(drvdata, config->fifofull_level, ETMFFLR);
> > - for (i = 0; i < drvdata->nr_addr_cmp; i++) {
> > + for (i = 0; i < caps->nr_addr_cmp; i++) {
> > etm_writel(drvdata, config->addr_val[i], ETMACVRn(i));
> > etm_writel(drvdata, config->addr_acctype[i], ETMACTRn(i));
> > }
> > - for (i = 0; i < drvdata->nr_cntr; i++) {
> > + for (i = 0; i < caps->nr_cntr; i++) {
> > etm_writel(drvdata, config->cntr_rld_val[i], ETMCNTRLDVRn(i));
> > etm_writel(drvdata, config->cntr_event[i], ETMCNTENRn(i));
> > etm_writel(drvdata, config->cntr_rld_event[i],
> > @@ -414,9 +415,9 @@ static int etm_enable_hw(struct etm_drvdata *drvdata)
> > etm_writel(drvdata, config->seq_32_event, ETMSQ32EVR);
> > etm_writel(drvdata, config->seq_13_event, ETMSQ13EVR);
> > etm_writel(drvdata, config->seq_curr_state, ETMSQR);
> > - for (i = 0; i < drvdata->nr_ext_out; i++)
> > + for (i = 0; i < caps->nr_ext_out; i++)
> > etm_writel(drvdata, ETM_DEFAULT_EVENT_VAL, ETMEXTOUTEVRn(i));
> > - for (i = 0; i < drvdata->nr_ctxid_cmp; i++)
> > + for (i = 0; i < caps->nr_ctxid_cmp; i++)
> > etm_writel(drvdata, config->ctxid_pid[i], ETMCIDCVRn(i));
> > etm_writel(drvdata, config->ctxid_mask, ETMCIDCMR);
> > etm_writel(drvdata, config->sync_freq, ETMSYNCFR);
> > @@ -572,7 +573,7 @@ static void etm_disable_hw(struct etm_drvdata *drvdata)
> > /* Read back sequencer and counters for post trace analysis */
> > config->seq_curr_state = (etm_readl(drvdata, ETMSQR) & ETM_SQR_MASK);
> > - for (i = 0; i < drvdata->nr_cntr; i++)
> > + for (i = 0; i < caps->nr_cntr; i++)
>
> caps undeclared.
>
> Thanks,
> Jie

Sorry to mistake. I'll change.

>
> > config->cntr_val[i] = etm_readl(drvdata, ETMCNTVRn(i));
> > etm_set_pwrdwn(drvdata);
> > @@ -754,7 +755,9 @@ static void etm_init_arch_data(void *info)
> > {
> > u32 etmidr;
> > u32 etmccr;
> > + u32 etmccer;
> > struct etm_drvdata *drvdata = info;
> > + struct etm_caps *caps = &drvdata->caps;
> > /* Make sure all registers are accessible */
> > etm_os_unlock(drvdata);
> > @@ -779,16 +782,18 @@ static void etm_init_arch_data(void *info)
> > /* Find all capabilities */
> > etmidr = etm_readl(drvdata, ETMIDR);
> > drvdata->arch = BMVAL(etmidr, 4, 11);
> > - drvdata->port_size = etm_readl(drvdata, ETMCR) & PORT_SIZE_MASK;
> > + caps->port_size = etm_readl(drvdata, ETMCR) & PORT_SIZE_MASK;
> > +
> > + etmccer = etm_readl(drvdata, ETMCCER);
> > + caps->timestamp = !!(drvdata->etmccer & ETMCCER_TIMESTAMP);
>
> caps->timestamp = !!(etmccer & ETMCCER_TIMESTAMP);
>
> > - drvdata->etmccer = etm_readl(drvdata, ETMCCER);
> > etmccr = etm_readl(drvdata, ETMCCR);
> > - drvdata->etmccr = etmccr;
> > - drvdata->nr_addr_cmp = BMVAL(etmccr, 0, 3) * 2;
> > - drvdata->nr_cntr = BMVAL(etmccr, 13, 15);
> > - drvdata->nr_ext_inp = BMVAL(etmccr, 17, 19);
> > - drvdata->nr_ext_out = BMVAL(etmccr, 20, 22);
> > - drvdata->nr_ctxid_cmp = BMVAL(etmccr, 24, 25);
> > + caps->fifofull = !!(drvdata->etmccr & ETMCCR_FIFOFULL);
>
> caps->fifofull = !!(etmccr & ETMCCR_FIFOFULL);
>
> > + caps->nr_addr_cmp = BMVAL(etmccr, 0, 3) * 2;
> > + caps->nr_cntr = BMVAL(etmccr, 13, 15);
> > + caps->nr_ext_inp = BMVAL(etmccr, 17, 19);
> > + caps->nr_ext_out = BMVAL(etmccr, 20, 22);
> > + caps->nr_ctxid_cmp = BMVAL(etmccr, 24, 25);
> > coresight_clear_self_claim_tag_unlocked(&drvdata->csa);
> > etm_set_pwrdwn(drvdata);
> > diff --git a/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c
> > index 762109307b86..0d8dac29d055 100644
> > --- a/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c
> > +++ b/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c
> > @@ -111,6 +111,7 @@ static ssize_t mode_store(struct device *dev,
> > int ret;
> > unsigned long val;
> > struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> > + const struct etm_caps *caps = &drvdata->caps;
> > struct etm_config *config = &drvdata->config;
> > ret = kstrtoul(buf, 16, &val);
> > @@ -131,7 +132,7 @@ static ssize_t mode_store(struct device *dev,
> > config->ctrl &= ~ETMCR_CYC_ACC;
> > if (config->mode & ETM_MODE_STALL) {
> > - if (!(drvdata->etmccr & ETMCCR_FIFOFULL)) {
> > + if (!caps->fifofull) {
> > dev_warn(dev, "stall mode not supported\n");
> > ret = -EINVAL;
> > goto err_unlock;
> > @@ -141,7 +142,7 @@ static ssize_t mode_store(struct device *dev,
> > config->ctrl &= ~ETMCR_STALL_MODE;
> > if (config->mode & ETM_MODE_TIMESTAMP) {
> > - if (!(drvdata->etmccer & ETMCCER_TIMESTAMP)) {
> > + if (!caps->timestamp) {
> > dev_warn(dev, "timestamp not supported\n");
> > ret = -EINVAL;
> > goto err_unlock;
> > @@ -286,13 +287,14 @@ static ssize_t addr_idx_store(struct device *dev,
> > int ret;
> > unsigned long val;
> > struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> > + const struct etm_caps *caps = &drvdata->caps;
> > struct etm_config *config = &drvdata->config;
> > ret = kstrtoul(buf, 16, &val);
> > if (ret)
> > return ret;
> > - if (val >= drvdata->nr_addr_cmp)
> > + if (val >= caps->nr_addr_cmp)
> > return -EINVAL;
> > /*
> > @@ -589,13 +591,14 @@ static ssize_t cntr_idx_store(struct device *dev,
> > int ret;
> > unsigned long val;
> > struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> > + const struct etm_caps *caps = &drvdata->caps;
> > struct etm_config *config = &drvdata->config;
> > ret = kstrtoul(buf, 16, &val);
> > if (ret)
> > return ret;
> > - if (val >= drvdata->nr_cntr)
> > + if (val >= caps->nr_cntr)
> > return -EINVAL;
> > /*
> > * Use spinlock to ensure index doesn't change while it gets
> > @@ -999,13 +1002,14 @@ static ssize_t ctxid_idx_store(struct device *dev,
> > int ret;
> > unsigned long val;
> > struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> > + const struct etm_caps *caps = &drvdata->caps;
> > struct etm_config *config = &drvdata->config;
> > ret = kstrtoul(buf, 16, &val);
> > if (ret)
> > return ret;
> > - if (val >= drvdata->nr_ctxid_cmp)
> > + if (val >= caps->nr_ctxid_cmp)
> > return -EINVAL;
> > /*
>

--
Sincerely,
Yeoreum Yun