From 3471644e4a4e249bb53fe43583369b4a652b4906 Mon Sep 17 00:00:00 2001 From: Tingwei Zhang Date: Tue, 13 Aug 2019 22:47:01 -0700 Subject: [PATCH] coresight: add support to enable multiple coresight paths Current coresight implementation supports enabling of a single path. This patch adds support to enable multiple source to sink paths. We build a path from source to sink when any source is enabled and store it in a list. When the source is disabled, we fetch the corresponding path from the list and decrement the refcount on each device in the path. The device is disabled if the refcount reaches zero. Don't store path to coresight data structure of source to avoid unnecessary change to ABI. Change-Id: Idd3dcfd0346bdfd39f41ac13e8e53068907c14e4 Signed-off-by: Satyajit Desai Signed-off-by: Rama Aparna Mallavarapu Signed-off-by: Mulu He Signed-off-by: Tingwei Zhang --- drivers/hwtracing/coresight/coresight.c | 101 +++++++++++++----------- 1 file changed, 56 insertions(+), 45 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c index 0ca512dd44f4..e9492150e845 100644 --- a/drivers/hwtracing/coresight/coresight.c +++ b/drivers/hwtracing/coresight/coresight.c @@ -36,18 +36,16 @@ struct coresight_node { }; /* - * When operating Coresight drivers from the sysFS interface, only a single - * path can exist from a tracer (associated to a CPU) to a sink. + * struct coresight_path - path from source to sink + * @path: Address of path list. + * @link: hook to the list. */ -static DEFINE_PER_CPU(struct list_head *, tracer_path); +struct coresight_path { + struct list_head *path; + struct list_head link; +}; -/* - * As of this writing only a single STM can be found in CS topologies. Since - * there is no way to know if we'll ever see more and what kind of - * configuration they will enact, for the time being only define a single path - * for STM. - */ -static struct list_head *stm_path; +static LIST_HEAD(cs_active_paths); /* * When losing synchronisation a new barrier packet needs to be inserted at the @@ -247,7 +245,7 @@ static void coresight_disable_sink(struct coresight_device *csdev) ret = sink_ops(csdev)->disable(csdev); if (ret) return; - csdev->enable = false; + csdev->activated = false; } static int coresight_enable_link(struct coresight_device *csdev, @@ -484,6 +482,20 @@ err: goto out; } +static struct coresight_device *coresight_get_source(struct list_head *path) +{ + struct coresight_device *csdev; + + if (!path) + return NULL; + + csdev = list_first_entry(path, struct coresight_node, link)->csdev; + if (csdev->type != CORESIGHT_DEV_TYPE_SOURCE) + return NULL; + + return csdev; +} + struct coresight_device *coresight_get_sink(struct list_head *path) { struct coresight_device *csdev; @@ -756,9 +768,23 @@ static int coresight_validate_source(struct coresight_device *csdev, return 0; } +static int coresight_store_path(struct list_head *path) +{ + struct coresight_path *node; + + node = kzalloc(sizeof(struct coresight_path), GFP_KERNEL); + if (!node) + return -ENOMEM; + + node->path = path; + list_add(&node->link, &cs_active_paths); + + return 0; +} + int coresight_enable(struct coresight_device *csdev) { - int cpu, ret = 0; + int ret = 0; struct coresight_device *sink; struct list_head *path; enum coresight_dev_subtype_source subtype; @@ -807,25 +833,9 @@ int coresight_enable(struct coresight_device *csdev) if (ret) goto err_source; - switch (subtype) { - case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC: - /* - * When working from sysFS it is important to keep track - * of the paths that were created so that they can be - * undone in 'coresight_disable()'. Since there can only - * be a single session per tracer (when working from sysFS) - * a per-cpu variable will do just fine. - */ - cpu = source_ops(csdev)->cpu_id(csdev); - per_cpu(tracer_path, cpu) = path; - break; - case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE: - stm_path = path; - break; - default: - /* We can't be here */ - break; - } + ret = coresight_store_path(path); + if (ret) + goto err_source; out: mutex_unlock(&coresight_mutex); @@ -842,8 +852,11 @@ EXPORT_SYMBOL_GPL(coresight_enable); void coresight_disable(struct coresight_device *csdev) { - int cpu, ret; + int ret; struct list_head *path = NULL; + struct coresight_path *cspath = NULL; + struct coresight_path *cspath_next = NULL; + struct coresight_device *src_csdev = NULL; mutex_lock(&coresight_mutex); @@ -854,20 +867,18 @@ void coresight_disable(struct coresight_device *csdev) if (!csdev->enable || !coresight_disable_source(csdev)) goto out; - switch (csdev->subtype.source_subtype) { - case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC: - cpu = source_ops(csdev)->cpu_id(csdev); - path = per_cpu(tracer_path, cpu); - per_cpu(tracer_path, cpu) = NULL; - break; - case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE: - path = stm_path; - stm_path = NULL; - break; - default: - /* We can't be here */ - break; + list_for_each_entry_safe(cspath, cspath_next, &cs_active_paths, link) { + src_csdev = coresight_get_source(cspath->path); + if (!src_csdev) + continue; + if (src_csdev == csdev) { + path = cspath->path; + list_del(&cspath->link); + kfree(cspath); + } } + if (path == NULL) + goto out; coresight_disable_path(path); coresight_release_path(path);