diff options
Diffstat (limited to 'drivers/hwtracing/coresight/coresight-etb10.c')
| -rw-r--r-- | drivers/hwtracing/coresight/coresight-etb10.c | 97 |
1 files changed, 68 insertions, 29 deletions
diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c index 105782ea64c7..4ee4c80a4354 100644 --- a/drivers/hwtracing/coresight/coresight-etb10.c +++ b/drivers/hwtracing/coresight/coresight-etb10.c @@ -5,6 +5,7 @@ * Description: CoreSight Embedded Trace Buffer driver */ +#include <linux/atomic.h> #include <linux/kernel.h> #include <linux/init.h> #include <linux/types.h> @@ -71,6 +72,8 @@ * @miscdev: specifics to handle "/dev/xyz.etb" entry. * @spinlock: only one at a time pls. * @reading: synchronise user space access to etb buffer. + * @pid: Process ID of the process being monitored by the session + * that is using this component. * @buf: area of memory where ETB buffer content gets sent. * @mode: this ETB is being used. * @buffer_depth: size of @buf. @@ -84,6 +87,7 @@ struct etb_drvdata { struct miscdevice miscdev; spinlock_t spinlock; local_t reading; + pid_t pid; u8 *buf; u32 mode; u32 buffer_depth; @@ -93,17 +97,9 @@ struct etb_drvdata { static int etb_set_buffer(struct coresight_device *csdev, struct perf_output_handle *handle); -static unsigned int etb_get_buffer_depth(struct etb_drvdata *drvdata) +static inline unsigned int etb_get_buffer_depth(struct etb_drvdata *drvdata) { - u32 depth = 0; - - pm_runtime_get_sync(drvdata->dev); - - /* RO registers don't need locking */ - depth = readl_relaxed(drvdata->base + ETB_RAM_DEPTH_REG); - - pm_runtime_put(drvdata->dev); - return depth; + return readl_relaxed(drvdata->base + ETB_RAM_DEPTH_REG); } static void __etb_enable_hw(struct etb_drvdata *drvdata) @@ -159,14 +155,15 @@ static int etb_enable_sysfs(struct coresight_device *csdev) goto out; } - /* Nothing to do, the tracer is already enabled. */ - if (drvdata->mode == CS_MODE_SYSFS) - goto out; + if (drvdata->mode == CS_MODE_DISABLED) { + ret = etb_enable_hw(drvdata); + if (ret) + goto out; - ret = etb_enable_hw(drvdata); - if (!ret) drvdata->mode = CS_MODE_SYSFS; + } + atomic_inc(csdev->refcnt); out: spin_unlock_irqrestore(&drvdata->spinlock, flags); return ret; @@ -175,29 +172,52 @@ out: static int etb_enable_perf(struct coresight_device *csdev, void *data) { int ret = 0; + pid_t pid; unsigned long flags; struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); + struct perf_output_handle *handle = data; spin_lock_irqsave(&drvdata->spinlock, flags); - /* No need to continue if the component is already in use. */ - if (drvdata->mode != CS_MODE_DISABLED) { + /* No need to continue if the component is already in used by sysFS. */ + if (drvdata->mode == CS_MODE_SYSFS) { + ret = -EBUSY; + goto out; + } + + /* Get a handle on the pid of the process to monitor */ + pid = task_pid_nr(handle->event->owner); + + if (drvdata->pid != -1 && drvdata->pid != pid) { ret = -EBUSY; goto out; } /* + * No HW configuration is needed if the sink is already in + * use for this session. + */ + if (drvdata->pid == pid) { + atomic_inc(csdev->refcnt); + goto out; + } + + /* * We don't have an internal state to clean up if we fail to setup * the perf buffer. So we can perform the step before we turn the * ETB on and leave without cleaning up. */ - ret = etb_set_buffer(csdev, (struct perf_output_handle *)data); + ret = etb_set_buffer(csdev, handle); if (ret) goto out; ret = etb_enable_hw(drvdata); - if (!ret) + if (!ret) { + /* Associate with monitored process. */ + drvdata->pid = pid; drvdata->mode = CS_MODE_PERF; + atomic_inc(csdev->refcnt); + } out: spin_unlock_irqrestore(&drvdata->spinlock, flags); @@ -325,27 +345,35 @@ static void etb_disable_hw(struct etb_drvdata *drvdata) coresight_disclaim_device(drvdata->base); } -static void etb_disable(struct coresight_device *csdev) +static int etb_disable(struct coresight_device *csdev) { struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); unsigned long flags; spin_lock_irqsave(&drvdata->spinlock, flags); - /* Disable the ETB only if it needs to */ - if (drvdata->mode != CS_MODE_DISABLED) { - etb_disable_hw(drvdata); - drvdata->mode = CS_MODE_DISABLED; + if (atomic_dec_return(csdev->refcnt)) { + spin_unlock_irqrestore(&drvdata->spinlock, flags); + return -EBUSY; } + + /* Complain if we (somehow) got out of sync */ + WARN_ON_ONCE(drvdata->mode == CS_MODE_DISABLED); + etb_disable_hw(drvdata); + /* Dissociate from monitored process. */ + drvdata->pid = -1; + drvdata->mode = CS_MODE_DISABLED; spin_unlock_irqrestore(&drvdata->spinlock, flags); dev_dbg(drvdata->dev, "ETB disabled\n"); + return 0; } -static void *etb_alloc_buffer(struct coresight_device *csdev, int cpu, - void **pages, int nr_pages, bool overwrite) +static void *etb_alloc_buffer(struct coresight_device *csdev, + struct perf_event *event, void **pages, + int nr_pages, bool overwrite) { - int node; + int node, cpu = event->cpu; struct cs_buffers *buf; if (cpu == -1) @@ -404,7 +432,7 @@ static unsigned long etb_update_buffer(struct coresight_device *csdev, const u32 *barrier; u32 read_ptr, write_ptr, capacity; u32 status, read_data; - unsigned long offset, to_read; + unsigned long offset, to_read = 0, flags; struct cs_buffers *buf = sink_config; struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); @@ -413,6 +441,12 @@ static unsigned long etb_update_buffer(struct coresight_device *csdev, capacity = drvdata->buffer_depth * ETB_FRAME_SIZE_WORDS; + spin_lock_irqsave(&drvdata->spinlock, flags); + + /* Don't do anything if another tracer is using this sink */ + if (atomic_read(csdev->refcnt) != 1) + goto out; + __etb_disable_hw(drvdata); CS_UNLOCK(drvdata->base); @@ -523,6 +557,8 @@ static unsigned long etb_update_buffer(struct coresight_device *csdev, } __etb_enable_hw(drvdata); CS_LOCK(drvdata->base); +out: + spin_unlock_irqrestore(&drvdata->spinlock, flags); return to_read; } @@ -720,7 +756,6 @@ static int etb_probe(struct amba_device *adev, const struct amba_id *id) spin_lock_init(&drvdata->spinlock); drvdata->buffer_depth = etb_get_buffer_depth(drvdata); - pm_runtime_put(&adev->dev); if (drvdata->buffer_depth & 0x80000000) return -EINVAL; @@ -730,6 +765,9 @@ static int etb_probe(struct amba_device *adev, const struct amba_id *id) if (!drvdata->buf) return -ENOMEM; + /* This device is not associated with a session */ + drvdata->pid = -1; + desc.type = CORESIGHT_DEV_TYPE_SINK; desc.subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_BUFFER; desc.ops = &etb_cs_ops; @@ -747,6 +785,7 @@ static int etb_probe(struct amba_device *adev, const struct amba_id *id) if (ret) goto err_misc_register; + pm_runtime_put(&adev->dev); return 0; err_misc_register: |