Messages in this thread Patch in this message | | | Date | Tue, 19 Jul 2022 22:45:00 +0100 | Subject | Re: [PATCH v2 05/13] coresight: etm3x: Update ETM3 driver to use Trace ID API | From | Suzuki K Poulose <> |
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On 04/07/2022 09:11, Mike Leach wrote: > Use the TraceID API to allocate ETM trace IDs dynamically. > > As with the etm4x we allocate on enable / disable for perf, > allocate on enable / reset for sysfs. > > Additionally we allocate on sysfs file read as both perf and sysfs > can read the ID before enabling the hardware. > > Remove sysfs option to write trace ID - which is inconsistent with > both the dynamic allocation method and the fixed allocation method > previously used. > > Signed-off-by: Mike Leach <mike.leach@linaro.org> > --- > drivers/hwtracing/coresight/coresight-etm.h | 2 + > .../coresight/coresight-etm3x-core.c | 68 +++++++++++++++++-- > .../coresight/coresight-etm3x-sysfs.c | 28 +++----- > 3 files changed, 71 insertions(+), 27 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-etm.h b/drivers/hwtracing/coresight/coresight-etm.h > index f3ab96eaf44e..3667428d38b6 100644 > --- a/drivers/hwtracing/coresight/coresight-etm.h > +++ b/drivers/hwtracing/coresight/coresight-etm.h > @@ -287,4 +287,6 @@ int etm_get_trace_id(struct etm_drvdata *drvdata); > void etm_set_default(struct etm_config *config); > void etm_config_trace_mode(struct etm_config *config); > struct etm_config *get_etm_config(struct etm_drvdata *drvdata); > +int etm_read_alloc_trace_id(struct etm_drvdata *drvdata); > +void etm_release_trace_id(struct etm_drvdata *drvdata); > #endif > diff --git a/drivers/hwtracing/coresight/coresight-etm3x-core.c b/drivers/hwtracing/coresight/coresight-etm3x-core.c > index d0ab9933472b..273f37be322b 100644 > --- a/drivers/hwtracing/coresight/coresight-etm3x-core.c > +++ b/drivers/hwtracing/coresight/coresight-etm3x-core.c > @@ -32,6 +32,7 @@ > > #include "coresight-etm.h" > #include "coresight-etm-perf.h" > +#include "coresight-trace-id.h" > > /* > * Not really modular but using module_param is the easiest way to > @@ -490,18 +491,61 @@ static int etm_trace_id(struct coresight_device *csdev) > return etm_get_trace_id(drvdata); > } > > +int etm_read_alloc_trace_id(struct etm_drvdata *drvdata) > +{ > + int trace_id; > + > + /* > + * This will allocate a trace ID to the cpu, > + * or return the one currently allocated. > + */ > + spin_lock(&drvdata->spinlock); > + trace_id = drvdata->traceid; > + if (!trace_id) { > + trace_id = coresight_trace_id_get_cpu_id(drvdata->cpu); > + if (trace_id > 0) > + drvdata->traceid = (u8)trace_id; > + } > + spin_unlock(&drvdata->spinlock); > + > + if (trace_id <= 0) > + pr_err("Failed to allocate trace ID for %s on CPU%d\n", > + dev_name(&drvdata->csdev->dev), drvdata->cpu);
dev_err(&drvdata->csdev->dev, ....)
> + > + return trace_id; > +} > + > +void etm_release_trace_id(struct etm_drvdata *drvdata) > +{ > + spin_lock(&drvdata->spinlock); > + coresight_trace_id_put_cpu_id(drvdata->cpu); > + drvdata->traceid = 0; > + spin_unlock(&drvdata->spinlock); > +} > + > static int etm_enable_perf(struct coresight_device *csdev, > struct perf_event *event) > { > struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); > + int ret; > > if (WARN_ON_ONCE(drvdata->cpu != smp_processor_id())) > return -EINVAL; > > /* Configure the tracer based on the session's specifics */ > etm_parse_event_config(drvdata, event); > + > + /* allocate a trace ID */ > + ret = etm_read_alloc_trace_id(drvdata); > + if (ret < 0) > + return ret; > + > /* And enable it */ > - return etm_enable_hw(drvdata); > + ret = etm_enable_hw(drvdata); > + > + if (ret) > + etm_release_trace_id(drvdata); > + return ret; > } > > static int etm_enable_sysfs(struct coresight_device *csdev) > @@ -510,6 +554,11 @@ static int etm_enable_sysfs(struct coresight_device *csdev) > struct etm_enable_arg arg = { }; > int ret; > > + /* allocate a trace ID */ > + ret = etm_read_alloc_trace_id(drvdata); > + if (ret < 0) > + return ret; > + > spin_lock(&drvdata->spinlock); > > /* > @@ -532,6 +581,8 @@ static int etm_enable_sysfs(struct coresight_device *csdev) > > if (!ret) > dev_dbg(&csdev->dev, "ETM tracing enabled\n"); > + else > + etm_release_trace_id(drvdata); > return ret; > } > > @@ -611,6 +662,8 @@ static void etm_disable_perf(struct coresight_device *csdev) > coresight_disclaim_device_unlocked(csdev); > > CS_LOCK(drvdata->base); > + > + etm_release_trace_id(drvdata); > } > > static void etm_disable_sysfs(struct coresight_device *csdev) > @@ -635,6 +688,13 @@ static void etm_disable_sysfs(struct coresight_device *csdev) > spin_unlock(&drvdata->spinlock); > cpus_read_unlock(); > > + /* > + * unlike for perf session - we only release trace IDs when resetting > + * sysfs. This permits sysfs users to read the trace ID after the trace > + * session has completed. This maintains operational behaviour with > + * prior trace id allocation method > + */ > + > dev_dbg(&csdev->dev, "ETM tracing disabled\n"); > } > > @@ -781,11 +841,6 @@ static void etm_init_arch_data(void *info) > CS_LOCK(drvdata->base); > } > > -static void etm_init_trace_id(struct etm_drvdata *drvdata) > -{ > - drvdata->traceid = coresight_get_trace_id(drvdata->cpu); > -} > - > static int __init etm_hp_setup(void) > { > int ret; > @@ -871,7 +926,6 @@ static int etm_probe(struct amba_device *adev, const struct amba_id *id) > if (etm_arch_supported(drvdata->arch) == false) > return -EINVAL; > > - etm_init_trace_id(drvdata); > etm_set_default(&drvdata->config); > > pdata = coresight_get_platform_data(dev); > diff --git a/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c > index 68fcbf4ce7a8..962d6ac96d64 100644 > --- a/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c > +++ b/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c > @@ -86,6 +86,8 @@ static ssize_t reset_store(struct device *dev, > > etm_set_default(config); > spin_unlock(&drvdata->spinlock); > + /* release trace id outside the spinlock as this fn uses it */ > + etm_release_trace_id(drvdata); > } > > return size; > @@ -1189,30 +1191,16 @@ static DEVICE_ATTR_RO(cpu); > static ssize_t traceid_show(struct device *dev, > struct device_attribute *attr, char *buf) > { > - unsigned long val; > - struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent); > - > - val = etm_get_trace_id(drvdata); > - > - return sprintf(buf, "%#lx\n", val); > -} > - > -static ssize_t traceid_store(struct device *dev, > - struct device_attribute *attr, > - const char *buf, size_t size) > -{ > - int ret; > - unsigned long val; > + int trace_id; > struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent); > > - ret = kstrtoul(buf, 16, &val); > - if (ret) > - return ret; > + trace_id = etm_read_alloc_trace_id(drvdata); > + if (trace_id < 0) > + return trace_id; > > - drvdata->traceid = val & ETM_TRACEID_MASK; > - return size; > + return sprintf(buf, "%#x\n", trace_id);
nit: while at this, please could we switch to sysfs_emit(). Rest looks fine to me.
Suzuki
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