[PATCH v6 11/13] coresight: etm3x: introduce struct etm_caps

Yeoreum Yun
2026-04-22T13:23:02Z

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 | 42 ++++++++++++-------
.../coresight/coresight-etm3x-core.c | 39 ++++++++++-------
.../coresight/coresight-etm3x-sysfs.c | 29 ++++++++-----
3 files changed, 67 insertions(+), 43 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm.h b/drivers/hwtracing/coresight/coresight-etm.h
index 40f20daded4f..932bec82fb47 100644
--- a/drivers/hwtracing/coresight/coresight-etm.h
+++ b/drivers/hwtracing/coresight/coresight-etm.h
@@ -140,6 +140,30 @@
ETM_ADD_COMP_0 | \
ETM_EVENT_NOT_A)

+/**
+ * struct etm_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.
+ * @retstack: Return stack 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;
+ bool retstack : 1;
+};
+
/**
* struct etm_config - configuration information related to an ETM
* @mode: controls various modes supported by this ETM/PTM.
@@ -212,19 +236,12 @@ 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 +251,12 @@ struct etm_drvdata {
struct coresight_device *csdev;
raw_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 4a702b515733..e42ca346da91 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x-core.c
@@ -308,6 +308,7 @@ void etm_config_trace_mode(struct etm_config *config)
static int etm_parse_event_config(struct etm_drvdata *drvdata,
struct perf_event *event)
{
+ const struct etm_caps *caps = &drvdata->caps;
struct etm_config *config = &drvdata->config;
struct perf_event_attr *attr = &event->attr;
u8 ts_level;
@@ -356,8 +357,7 @@ static int etm_parse_event_config(struct etm_drvdata *drvdata,
* has ret stack) on the same SoC. So only enable when it can be honored
* - trace will still continue normally otherwise.
*/
- if (ATTR_CFG_GET_FLD(attr, retstack) &&
- (drvdata->etmccer & ETMCCER_RETSTACK))
+ if (ATTR_CFG_GET_FLD(attr, retstack) && (caps->retstack))
config->ctrl |= ETMCR_RETURN_STACK;

return 0;
@@ -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);
@@ -563,6 +564,7 @@ static int etm_enable(struct coresight_device *csdev, struct perf_event *event,
static void etm_disable_hw(struct etm_drvdata *drvdata)
{
int i;
+ const struct etm_caps *caps = &drvdata->caps;
struct etm_config *config = &drvdata->config;
struct coresight_device *csdev = drvdata->csdev;

@@ -572,7 +574,7 @@ 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++)
config->cntr_val[i] = etm_readl(drvdata, ETMCNTVRn(i));

etm_set_pwrdwn(drvdata);
@@ -754,7 +756,9 @@ 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 +783,19 @@ 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 = !!(etmccer & ETMCCER_TIMESTAMP);
+ caps->retstack = !!(etmccer & ETMCCER_RETSTACK);

- 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 = !!(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 42b12c33516b..f7330d830e21 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c
@@ -15,8 +15,9 @@ static ssize_t nr_addr_cmp_show(struct device *dev,
{
unsigned long val;
struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
+ const struct etm_caps *caps = &drvdata->caps;

- val = drvdata->nr_addr_cmp;
+ val = caps->nr_addr_cmp;
return sprintf(buf, "%#lx\n", val);
}
static DEVICE_ATTR_RO(nr_addr_cmp);
@@ -25,8 +26,9 @@ static ssize_t nr_cntr_show(struct device *dev,
struct device_attribute *attr, char *buf)
{ unsigned long val;
struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
+ const struct etm_caps *caps = &drvdata->caps;

- val = drvdata->nr_cntr;
+ val = caps->nr_cntr;
return sprintf(buf, "%#lx\n", val);
}
static DEVICE_ATTR_RO(nr_cntr);
@@ -37,7 +39,7 @@ static ssize_t nr_ctxid_cmp_show(struct device *dev,
unsigned long val;
struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);

- val = drvdata->nr_ctxid_cmp;
+ val = drvdata->caps.nr_ctxid_cmp;
return sprintf(buf, "%#lx\n", val);
}
static DEVICE_ATTR_RO(nr_ctxid_cmp);
@@ -80,7 +82,7 @@ static ssize_t reset_store(struct device *dev,
memset(config, 0, sizeof(struct etm_config));
config->mode = ETM_MODE_EXCLUDE;
config->trigger_event = ETM_DEFAULT_EVENT_VAL;
- for (i = 0; i < drvdata->nr_addr_cmp; i++) {
+ for (i = 0; i < drvdata->caps.nr_addr_cmp; i++) {
config->addr_type[i] = ETM_ADDR_TYPE_NONE;
}

@@ -111,6 +113,7 @@ 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 +134,7 @@ 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 +144,7 @@ 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 +289,14 @@ 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 +593,14 @@ 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
@@ -720,18 +725,19 @@ static ssize_t cntr_val_show(struct device *dev,
int i, ret = 0;
u32 val;
struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
+ const struct etm_caps *caps = &drvdata->caps;
struct etm_config *config = &drvdata->config;

if (!coresight_get_mode(drvdata->csdev)) {
raw_spin_lock(&drvdata->spinlock);
- for (i = 0; i < drvdata->nr_cntr; i++)
+ for (i = 0; i < caps->nr_cntr; i++)
ret += sprintf(buf, "counter %d: %x\n",
i, config->cntr_val[i]);
raw_spin_unlock(&drvdata->spinlock);
return ret;
}

- for (i = 0; i < drvdata->nr_cntr; i++) {
+ for (i = 0; i < caps->nr_cntr; i++) {
val = etm_readl(drvdata, ETMCNTVRn(i));
ret += sprintf(buf, "counter %d: %x\n", i, val);
}
@@ -999,13 +1005,14 @@ 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;

/*