From a685d68328f14579b2e68d6a3a2066089cffbf98 Mon Sep 17 00:00:00 2001 From: Mathieu Poirier Date: Tue, 3 May 2016 11:33:38 -0600 Subject: [PATCH] coresight: adding path for STM device >From a core framework point of view an STM device is a source that is treated the same way as any other tracers. Unlike tracers though STM devices are not associated with a CPU. As such it doesn't make sense to associate the path from an STM device to its sink with a per-cpu variable as it is done for tracers. This patch simply adds another global variable to keep STM paths and the processing in coresight_enable/disable() is updated to deal with STM devices properly. Signed-off-by: Mathieu Poirier Signed-off-by: Chunyan Zhang Signed-off-by: Greg Kroah-Hartman --- drivers/hwtracing/coresight/coresight.c | 106 ++++++++++++++++++------ 1 file changed, 82 insertions(+), 24 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c index 945bc31f0ec5..0995df8f85bc 100644 --- a/drivers/hwtracing/coresight/coresight.c +++ b/drivers/hwtracing/coresight/coresight.c @@ -43,7 +43,15 @@ 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. */ -static DEFINE_PER_CPU(struct list_head *, sysfs_path); +static DEFINE_PER_CPU(struct list_head *, tracer_path); + +/* + * 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 int coresight_id_match(struct device *dev, void *data) { @@ -432,18 +440,45 @@ void coresight_release_path(struct list_head *path) path = NULL; } +/** coresight_validate_source - make sure a source has the right credentials + * @csdev: the device structure for a source. + * @function: the function this was called from. + * + * Assumes the coresight_mutex is held. + */ +static int coresight_validate_source(struct coresight_device *csdev, + const char *function) +{ + u32 type, subtype; + + type = csdev->type; + subtype = csdev->subtype.source_subtype; + + if (type != CORESIGHT_DEV_TYPE_SOURCE) { + dev_err(&csdev->dev, "wrong device type in %s\n", function); + return -EINVAL; + } + + if (subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_PROC && + subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE) { + dev_err(&csdev->dev, "wrong device subtype in %s\n", function); + return -EINVAL; + } + + return 0; +} + int coresight_enable(struct coresight_device *csdev) { - int ret = 0; - int cpu; + int cpu, ret = 0; struct list_head *path; mutex_lock(&coresight_mutex); - if (csdev->type != CORESIGHT_DEV_TYPE_SOURCE) { - ret = -EINVAL; - dev_err(&csdev->dev, "wrong device type in %s\n", __func__); + + ret = coresight_validate_source(csdev, __func__); + if (ret) goto out; - } + if (csdev->enable) goto out; @@ -461,15 +496,25 @@ int coresight_enable(struct coresight_device *csdev) if (ret) goto err_source; - /* - * 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(sysfs_path, cpu) = path; + switch (csdev->subtype.source_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; + } out: mutex_unlock(&coresight_mutex); @@ -486,23 +531,36 @@ EXPORT_SYMBOL_GPL(coresight_enable); void coresight_disable(struct coresight_device *csdev) { - int cpu; - struct list_head *path; + int cpu, ret; + struct list_head *path = NULL; mutex_lock(&coresight_mutex); - if (csdev->type != CORESIGHT_DEV_TYPE_SOURCE) { - dev_err(&csdev->dev, "wrong device type in %s\n", __func__); + + ret = coresight_validate_source(csdev, __func__); + if (ret) goto out; - } + if (!csdev->enable) goto out; - cpu = source_ops(csdev)->cpu_id(csdev); - path = per_cpu(sysfs_path, cpu); + 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; + } + coresight_disable_source(csdev); coresight_disable_path(path); coresight_release_path(path); - per_cpu(sysfs_path, cpu) = NULL; out: mutex_unlock(&coresight_mutex);