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coresight: etm3x: Update ETM3 driver to use Trace ID API

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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>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230116124928.5440-7-mike.leach@linaro.org
This commit is contained in:
Mike Leach 2023-01-16 12:49:19 +00:00 committed by Suzuki K Poulose
parent df4871204e
commit 9edf291091
4 changed files with 76 additions and 27 deletions
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2
Documentation/ABI/testing/sysfs-bus-coresight-devices-etm3x
View File

@ -236,7 +236,7 @@ What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/traceid
Date: November 2014
KernelVersion: 3.19
Contact: Mathieu Poirier <mathieu.poirier@linaro.org>
Description: (RW) Holds the trace ID that will appear in the trace stream
Description: (RO) Holds the trace ID that will appear in the trace stream
coming from this trace entity.
What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/trigger_event

2
drivers/hwtracing/coresight/coresight-etm.h
View File

@ -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

72
drivers/hwtracing/coresight/coresight-etm3x-core.c
View File

@ -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
@ -490,16 +491,59 @@ 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.
*
* trace id function has its own lock
*/
trace_id = coresight_trace_id_get_cpu_id(drvdata->cpu);
if (IS_VALID_CS_TRACE_ID(trace_id))
drvdata->traceid = (u8)trace_id;
else
dev_err(&drvdata->csdev->dev,
"Failed to allocate trace ID for %s on CPU%d\n",
dev_name(&drvdata->csdev->dev), drvdata->cpu);
return trace_id;
}
void etm_release_trace_id(struct etm_drvdata *drvdata)
{
coresight_trace_id_put_cpu_id(drvdata->cpu);
}
static int etm_enable_perf(struct coresight_device *csdev,
struct perf_event *event)
{
struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
int trace_id;
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);
/*
* perf allocates cpu ids as part of _setup_aux() - device needs to use
* the allocated ID. This reads the current version without allocation.
*
* This does not use the trace id lock to prevent lock_dep issues
* with perf locks - we know the ID cannot change until perf shuts down
* the session
*/
trace_id = coresight_trace_id_read_cpu_id(drvdata->cpu);
if (!IS_VALID_CS_TRACE_ID(trace_id)) {
dev_err(&drvdata->csdev->dev, "Failed to set trace ID for %s on CPU%d\n",
dev_name(&drvdata->csdev->dev), drvdata->cpu);
return -EINVAL;
}
drvdata->traceid = (u8)trace_id;
/* And enable it */
return etm_enable_hw(drvdata);
}
@ -512,6 +556,11 @@ static int etm_enable_sysfs(struct coresight_device *csdev)
spin_lock(&drvdata->spinlock);
/* sysfs needs to allocate and set a trace ID */
ret = etm_read_alloc_trace_id(drvdata);
if (ret < 0)
goto unlock_enable_sysfs;
/*
* Configure the ETM only if the CPU is online. If it isn't online
* hw configuration will take place on the local CPU during bring up.
@ -528,6 +577,10 @@ static int etm_enable_sysfs(struct coresight_device *csdev)
ret = -ENODEV;
}
if (ret)
etm_release_trace_id(drvdata);
unlock_enable_sysfs:
spin_unlock(&drvdata->spinlock);
if (!ret)
@ -611,6 +664,12 @@ static void etm_disable_perf(struct coresight_device *csdev)
coresight_disclaim_device_unlocked(csdev);
CS_LOCK(drvdata->base);
/*
* perf will release trace ids when _free_aux()
* is called at the end of the session
*/
}
static void etm_disable_sysfs(struct coresight_device *csdev)
@ -635,6 +694,13 @@ static void etm_disable_sysfs(struct coresight_device *csdev)
spin_unlock(&drvdata->spinlock);
cpus_read_unlock();
/*
* 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 +847,6 @@ 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 +932,6 @@ 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);

27
drivers/hwtracing/coresight/coresight-etm3x-sysfs.c
View File

@ -85,6 +85,7 @@ static ssize_t reset_store(struct device *dev,
}
etm_set_default(config);
etm_release_trace_id(drvdata);
spin_unlock(&drvdata->spinlock);
}
@ -1189,30 +1190,16 @@ static DEVICE_ATTR_RO(cpu);
static ssize_t traceid_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
unsigned long val;
int trace_id;
struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
val = etm_get_trace_id(drvdata);
trace_id = etm_read_alloc_trace_id(drvdata);
if (trace_id < 0)
return trace_id;
return sprintf(buf, "%#lx\n", val);
return sysfs_emit(buf, "%#x\n", trace_id);
}
static ssize_t traceid_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t size)
{
int ret;
unsigned long val;
struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
ret = kstrtoul(buf, 16, &val);
if (ret)
return ret;
drvdata->traceid = val & ETM_TRACEID_MASK;
return size;
}
static DEVICE_ATTR_RW(traceid);
static DEVICE_ATTR_RO(traceid);
static struct attribute *coresight_etm_attrs[] = {
&dev_attr_nr_addr_cmp.attr,