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

From: Jie Gan

Date: Sun Apr 12 2026 - 10:24:23 EST




On 4/12/2026 10:21 PM, Jie Gan wrote:


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@xxxxxxx>
---
  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

Have comments below in previous message... ignore the mistake to end the message...


          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;
      /*