On Wed, Apr 15, 2026 at 05:55:20PM +0100, Yeoreum Yun wrote:
[...]
@@ -573,11 +573,9 @@ 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_status[i], TRCSSCSRn(i));
/* always clear status and pending bits on restart if using single-shot */etm4x_relaxed_write32(csa, 0x0, TRCSSCSRn(i));
In Arm ARM, D24.4.60 TRCSSCSR<n>, bits[0..3] are RO. I think it is fine for directly clear the regiser with zero (means it will only clear status / pending bits).
[...]
@@ -1841,10 +1839,11 @@ 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_cmp[config->ss_idx]; raw_spin_unlock(&drvdata->spinlock); return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
}
This sysfs knob never can print out a realtime status for sshot, I am fine for only printing caps->ss_cmp, this can avoid any misleading.
@Suzuki, @Mike, do you agree with the change above?
If maintainers agree with this, as Jie suggested, it is good to add a comment in the code and update the document:
Documentation/trace/coresight/coresight-etm4x-reference.rst
Thanks, Leo