From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Mathieu Poirier Subject: [PATCH 3/7] coresight: Use event attributes for sink selection Date: Tue, 15 Jan 2019 16:07:38 -0700 Message-Id: <20190115230742.13730-4-mathieu.poirier@linaro.org> In-Reply-To: <20190115230742.13730-1-mathieu.poirier@linaro.org> References: <20190115230742.13730-1-mathieu.poirier@linaro.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org List-Archive: To: acme@kernel.org, peterz@infradead.org, gregkh@linuxfoundation.org Cc: mark.rutland@arm.com, linux-s390@vger.kernel.org, suzuki.poulose@arm.com, alexander.shishkin@linux.intel.com, will.deacon@arm.com, heiko.carstens@de.ibm.com, adrian.hunter@intel.com, ast@kernel.org, mingo@redhat.com, linux-arm-kernel@lists.infradead.org, hpa@zytor.com, schwidefsky@de.ibm.com, namhyung@kernel.org, tglx@linutronix.de, jolsa@redhat.com, linux-kernel@vger.kernel.org List-ID: This patch uses the information conveyed by perf_event::attr::config2 to select a sink to use for the session. That way a sink can easily be selected to be used by more than one source, something that isn't currently possible with the sysfs implementation. Signed-off-by: Mathieu Poirier --- .../hwtracing/coresight/coresight-etm-perf.c | 16 ++------ drivers/hwtracing/coresight/coresight-priv.h | 1 + drivers/hwtracing/coresight/coresight.c | 39 +++++++++++++++++++ 3 files changed, 44 insertions(+), 12 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c index 292bd409a68c..685d16001d0b 100644 --- a/drivers/hwtracing/coresight/coresight-etm-perf.c +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c @@ -201,18 +201,10 @@ static void *etm_setup_aux(struct perf_event *event, void **pages, return NULL; INIT_WORK(&event_data->work, free_event_data); - /* - * In theory nothing prevent tracers in a trace session from being - * associated with different sinks, nor having a sink per tracer. But - * until we have HW with this kind of topology we need to assume tracers - * in a trace session are using the same sink. Therefore go through - * the coresight bus and pick the first enabled sink. - * - * When operated from sysFS users are responsible to enable the sink - * while from perf, the perf tools will do it based on the choice made - * on the cmd line. As such the "enable_sink" flag in sysFS is reset. - */ - sink = coresight_get_enabled_sink(true); + /* First get the selected sink from user space. */ + sink = coresight_get_sink_by_id(event->attr.config2); + if (!sink) + sink = coresight_get_enabled_sink(true); if (!sink || !sink_ops(sink)->alloc_buffer) goto err; diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h index 579f34943bf1..071bb98d358f 100644 --- a/drivers/hwtracing/coresight/coresight-priv.h +++ b/drivers/hwtracing/coresight/coresight-priv.h @@ -147,6 +147,7 @@ void coresight_disable_path(struct list_head *path); int coresight_enable_path(struct list_head *path, u32 mode, void *sink_data); struct coresight_device *coresight_get_sink(struct list_head *path); struct coresight_device *coresight_get_enabled_sink(bool reset); +struct coresight_device *coresight_get_sink_by_id(u64 id); struct list_head *coresight_build_path(struct coresight_device *csdev, struct coresight_device *sink); void coresight_release_path(struct list_head *path); diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c index 526f122a38ee..7e2ce0beb2a0 100644 --- a/drivers/hwtracing/coresight/coresight.c +++ b/drivers/hwtracing/coresight/coresight.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #include #include @@ -541,6 +542,44 @@ struct coresight_device *coresight_get_enabled_sink(bool deactivate) return dev ? to_coresight_device(dev) : NULL; } +static int coresight_sink_by_id(struct device *dev, void *data) +{ + struct coresight_device *csdev = to_coresight_device(dev); + unsigned long hash; + + if (csdev->type == CORESIGHT_DEV_TYPE_SINK || + csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) { + /* + * See function etm_perf_sink_name_show() to know where this + * comes from. + */ + hash = hashlen_hash(hashlen_string(NULL, dev_name(dev))); + + if (hash == (*(unsigned long *)data)) + return 1; + } + + return 0; +} + +/** + * coresight_get_sink_by_id - returns the sink that matches the id + * @id: Id of the sink to match + * + * The name of a sink is unique, whether it is found on the AMBA bus or + * otherwise. As such the hash of that name can easily be used to identify + * a sink. + */ +struct coresight_device *coresight_get_sink_by_id(u64 id) +{ + struct device *dev = NULL; + + dev = bus_find_device(&coresight_bustype, NULL, &id, + coresight_sink_by_id); + + return dev ? to_coresight_device(dev) : NULL; +} + /* * coresight_grab_device - Power up this device and any of the helper * devices connected to it for trace operation. Since the helper devices -- 2.17.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel