Re: [PATCH v3 2/5] coresight: etm4x: exclude ss_status from drvdata->config

Yeoreum Yun
2026-04-13T10:04:46Z

Hi Jie,

>
>
> On 4/13/2026 1:55 AM, Yeoreum Yun wrote:
> > The purpose of TRCSSCSRn register is to show status of
> > the corresponding Single-shot Comparator Control and input supports.
> > That means writable field's purpose for reset or restore from idle status
> > not for configuration.
> >
> > Therefore, exclude ss_status from drvdata->config, move it to etm4x_caps.
> > This includes remove TRCSSCRn from configurable item and
> > remove saving in etm4_disable_hw().
> >
> > Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
> > ---
> > .../hwtracing/coresight/coresight-etm4x-cfg.c | 1 -
> > .../hwtracing/coresight/coresight-etm4x-core.c | 18 +++++-------------
> > .../coresight/coresight-etm4x-sysfs.c | 7 ++-----
> > drivers/hwtracing/coresight/coresight-etm4x.h | 3 ++-
> > 4 files changed, 9 insertions(+), 20 deletions(-)
> >
> > diff --git a/drivers/hwtracing/coresight/coresight-etm4x-cfg.c b/drivers/hwtracing/coresight/coresight-etm4x-cfg.c
> > index c302072b293a..d14d7c8a23e5 100644
> > --- a/drivers/hwtracing/coresight/coresight-etm4x-cfg.c
> > +++ b/drivers/hwtracing/coresight/coresight-etm4x-cfg.c
> > @@ -86,7 +86,6 @@ static int etm4_cfg_map_reg_offset(struct etmv4_drvdata *drvdata,
> > off_mask = (offset & GENMASK(11, 5));
> > do {
> > CHECKREGIDX(TRCSSCCRn(0), ss_ctrl, idx, off_mask);
> > - CHECKREGIDX(TRCSSCSRn(0), ss_status, idx, off_mask);
> > CHECKREGIDX(TRCSSPCICRn(0), ss_pe_cmp, idx, off_mask);
> > } while (0);
> > } else if ((offset >= TRCCIDCVRn(0)) && (offset <= TRCVMIDCVRn(7))) {
> > diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> > index 6443f3717b37..8ebfd3924143 100644
> > --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
> > +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> > @@ -91,7 +91,7 @@ static bool etm4x_sspcicrn_present(struct etmv4_drvdata *drvdata, int n)
> > const struct etmv4_caps *caps = &drvdata->caps;
> > return (n < caps->nr_ss_cmp) && caps->nr_pe &&
> > - (drvdata->config.ss_status[n] & TRCSSCSRn_PC);
> > + (caps->ss_status[n] & TRCSSCSRn_PC);
> > }
> > u64 etm4x_sysreg_read(u32 offset, bool _relaxed, bool _64bit)
> > @@ -571,11 +571,9 @@ static int etm4_enable_hw(struct etmv4_drvdata *drvdata)
> > etm4x_relaxed_write32(csa, config->res_ctrl[i], TRCRSCTLRn(i));
> > for (i = 0; i < caps->nr_ss_cmp; i++) {
> > - /* always clear status bit on restart if using single-shot */
> > - if (config->ss_ctrl[i] || config->ss_pe_cmp[i])
> > - config->ss_status[i] &= ~TRCSSCSRn_STATUS;
> > etm4x_relaxed_write32(csa, config->ss_ctrl[i], TRCSSCCRn(i));
> > - etm4x_relaxed_write32(csa, config->ss_status[i], TRCSSCSRn(i));
> > + /* always clear status and pending bits on restart if using single-shot */
> > + etm4x_relaxed_write32(csa, caps->ss_status[i], TRCSSCSRn(i));
> > if (etm4x_sspcicrn_present(drvdata, i))
> > etm4x_relaxed_write32(csa, config->ss_pe_cmp[i], TRCSSPCICRn(i));
> > }
> > @@ -1053,12 +1051,6 @@ static void etm4_disable_hw(struct etmv4_drvdata *drvdata)
> > etm4_disable_trace_unit(drvdata);
> > - /* read the status of the single shot comparators */
> > - for (i = 0; i < caps->nr_ss_cmp; i++) {
> > - config->ss_status[i] =
> > - etm4x_relaxed_read32(csa, TRCSSCSRn(i));
> > - }
> > -
> > /* read back the current counter values */
> > for (i = 0; i < caps->nr_cntr; i++) {
> > config->cntr_val[i] =
> > @@ -1501,8 +1493,8 @@ static void etm4_init_arch_data(void *info)
> > */
> > caps->nr_ss_cmp = FIELD_GET(TRCIDR4_NUMSSCC_MASK, etmidr4);
> > for (i = 0; i < caps->nr_ss_cmp; i++) {
> > - drvdata->config.ss_status[i] =
> > - etm4x_relaxed_read32(csa, TRCSSCSRn(i));
> > + caps->ss_status[i] = etm4x_relaxed_read32(csa, TRCSSCSRn(i));
> > + caps->ss_status[i] &= ~(TRCSSCSRn_STATUS | TRCSSCSRn_PENDING);
> > }
> > /* NUMCIDC, bits[27:24] number of Context ID comparators for tracing */
> > caps->numcidc = FIELD_GET(TRCIDR4_NUMCIDC_MASK, etmidr4);
> > diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> > index 50408215d1ac..dd62f01674cf 100644
> > --- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> > +++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> > @@ -1827,8 +1827,6 @@ static ssize_t sshot_ctrl_store(struct device *dev,
> > raw_spin_lock(&drvdata->spinlock);
> > idx = config->ss_idx;
> > config->ss_ctrl[idx] = FIELD_PREP(TRCSSCCRn_SAC_ARC_RST_MASK, val);
> > - /* must clear bit 31 in related status register on programming */
> > - config->ss_status[idx] &= ~TRCSSCSRn_STATUS;
> > raw_spin_unlock(&drvdata->spinlock);
> > return size;
> > }
> > @@ -1839,10 +1837,11 @@ static ssize_t sshot_status_show(struct device *dev,
> > {
> > unsigned long val;
> > struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
> > + const struct etmv4_caps *caps = &drvdata->caps;
> > struct etmv4_config *config = &drvdata->config;
> > raw_spin_lock(&drvdata->spinlock);
> > - val = config->ss_status[config->ss_idx];
> > + val = caps->ss_status[config->ss_idx];
> > raw_spin_unlock(&drvdata->spinlock);
> > return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
> > }
> > @@ -1877,8 +1876,6 @@ static ssize_t sshot_pe_ctrl_store(struct device *dev,
> > raw_spin_lock(&drvdata->spinlock);
> > idx = config->ss_idx;
> > config->ss_pe_cmp[idx] = FIELD_PREP(TRCSSPCICRn_PC_MASK, val);
> > - /* must clear bit 31 in related status register on programming */
> > - config->ss_status[idx] &= ~TRCSSCSRn_STATUS;
> > raw_spin_unlock(&drvdata->spinlock);
> > return size;
> > }
> > diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h
> > index 8eebb83fcaeb..3cc1ca76c933 100644
> > --- a/drivers/hwtracing/coresight/coresight-etm4x.h
> > +++ b/drivers/hwtracing/coresight/coresight-etm4x.h
> > @@ -213,6 +213,7 @@
> > #define TRCACATRn_EXLEVEL_MASK GENMASK(14, 8)
> > #define TRCSSCSRn_STATUS BIT(31)
> > +#define TRCSSCSRn_PENDING BIT(30)
> > #define TRCSSCCRn_SAC_ARC_RST_MASK GENMASK(24, 0)
> > #define TRCSSPCICRn_PC_MASK GENMASK(7, 0)
> > @@ -898,6 +899,7 @@ struct etmv4_caps {
> > bool atbtrig : 1;
> > bool lpoverride : 1;
> > bool skip_power_up : 1;
> > + u32 ss_status[ETM_MAX_SS_CMP];
>
> Needs kernel_doc also.

Thanks .I'll add comment for ss_status
>
> Thanks,
> Jie
>
>
> > };
> > /**
> > @@ -976,7 +978,6 @@ struct etmv4_config {
> > u32 res_ctrl[ETM_MAX_RES_SEL]; /* TRCRSCTLRn */
> > u8 ss_idx;
> > u32 ss_ctrl[ETM_MAX_SS_CMP];
> > - u32 ss_status[ETM_MAX_SS_CMP];
> > u32 ss_pe_cmp[ETM_MAX_SS_CMP];
> > u8 addr_idx;
> > u64 addr_val[ETM_MAX_SINGLE_ADDR_CMP];
>

--
Sincerely,
Yeoreum Yun