Enhancing skeleton PMU with event initialisation. The function makes sure tracers aren't already enabled before going through with the powe up and configuration sequences.
Signed-off-by: Mathieu Poirier <[email protected]> --- drivers/hwtracing/coresight/coresight-etm-perf.c | 176 +++++++++++++++++++++++ 1 file changed, 176 insertions(+) diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c index 759b8d69b4e6..a21171a3e929 100644 --- a/drivers/hwtracing/coresight/coresight-etm-perf.c +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c @@ -30,6 +30,9 @@ static struct pmu etm_pmu; +static DEFINE_PER_CPU(struct coresight_device *, csdev_src); +static DEFINE_PER_CPU(struct coresight_device *, csdev_sink); + /* ETMCR is 'config' */ PMU_FORMAT_ATTR(cycacc, "config:12"); PMU_FORMAT_ATTR(timestamp, "config:28"); @@ -52,6 +55,178 @@ static const struct attribute_group *etm_pmu_attr_groups[] = { static void etm_event_read(struct perf_event *event) {} +static int etm_event_power_single_source(int source, bool power) +{ + int ret = 0; + LIST_HEAD(path); + LIST_HEAD(sinks); + struct coresight_device *csdev; + + csdev = per_cpu(csdev_src, source); + + if (!csdev) + return -EINVAL; + + if (csdev->type != CORESIGHT_DEV_TYPE_SOURCE) + return -EINVAL; + + if (power) { + ret = source_ops(csdev)->poweron(csdev); + if (ret) + goto out; + + ret = coresight_build_paths(csdev, &path, &sinks, true); + if (ret) { + dev_dbg(&csdev->dev, "creating path(s) failed\n"); + source_ops(csdev)->poweroff(csdev); + } + + /* Everything is good, record first enabled sink buffer */ + per_cpu(csdev_sink, source) = + list_first_entry(&sinks, + struct coresight_device, sinks); + } else { + source_ops(csdev)->poweroff(csdev); + ret = coresight_build_paths(csdev, &path, NULL, false); + if (ret) + dev_dbg(&csdev->dev, "releasing path(s) failed\n"); + } + +out: + return ret; +} + +static int etm_event_power_sources(int source, bool power) +{ + int cpu, ret; + + if (source < -1 || source >= nr_cpu_ids) + return -EINVAL; + + /* source == -1 is for all CPUs. */ + if (source != -1) { + /* power up/down one source */ + ret = etm_event_power_single_source(source, power); + goto out; + } + + /* same process as above, but for all CPUs */ + for_each_online_cpu(cpu) { + ret = etm_event_power_single_source(cpu, power); + if (ret) + break; + } + +out: + return ret; +} + +static int etm_event_config_single_source(int source) +{ + struct coresight_device *csdev; + + csdev = per_cpu(csdev_src, source); + + if (!csdev) + return -EINVAL; + + if (csdev->type != CORESIGHT_DEV_TYPE_SOURCE) + return -EINVAL; + + return source_ops(csdev)->configure(csdev); +} + +static int etm_event_config_sources(int source) +{ + int cpu, ret; + + if (source < -1 || source >= nr_cpu_ids) + return -EINVAL; + + /* source == -1 is for all CPUs. */ + if (source != -1) { + /* configure one source */ + ret = etm_event_config_single_source(source); + goto out; + } + + /* same process as above, but for all CPUs */ + for_each_online_cpu(cpu) { + ret = etm_event_config_single_source(cpu); + if (ret) + goto reset; + } + +out: + return ret; +reset: + for_each_online_cpu(cpu) + etm_event_power_sources(cpu, false); + goto out; +} + +static bool etm_event_source_single_enabled(int source) +{ + struct coresight_device *csdev = per_cpu(csdev_src, source); + + if (!csdev) + return true; + + return source_ops(csdev)->is_enabled(csdev); +} + +static bool etm_event_source_enabled(int source) +{ + int cpu; + + if (source != -1) + return etm_event_source_single_enabled(source); + + for_each_online_cpu(cpu) { + if (etm_event_source_single_enabled(cpu)) + return true; + } + + return false; +} + +static void etm_event_destroy(struct perf_event *event) +{ + /* switching off the source will also tear down the path */ + etm_event_power_sources(event->cpu, false); +} + +static int etm_event_init(struct perf_event *event) +{ + int ret; + + if (event->attr.type != etm_pmu.type) + return -ENOENT; + + if (event->cpu >= nr_cpu_ids) + return -EINVAL; + + /* only one session at a time */ + if (etm_event_source_enabled(event->cpu)) + return -EBUSY; + + /* + * Make sure CPUs don't disappear between the + * power up sequence and configuration. + */ + get_online_cpus(); + ret = etm_event_power_sources(event->cpu, true); + if (ret) + goto out; + + ret = etm_event_config_sources(event->cpu); + + event->destroy = etm_event_destroy; +out: + put_online_cpus(); + return ret; +} + static int __init etm_perf_init(void) { etm_pmu.capabilities = PERF_PMU_CAP_EXCLUSIVE; @@ -59,6 +234,7 @@ static int __init etm_perf_init(void) etm_pmu.attr_groups = etm_pmu_attr_groups; etm_pmu.task_ctx_nr = perf_sw_context; etm_pmu.read = etm_event_read; + etm_pmu.event_init = etm_event_init; return perf_pmu_register(&etm_pmu, CORESIGHT_ETM_PMU_NAME, -1); } -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
