diff options
Diffstat (limited to 'include/linux/coresight.h')
| -rw-r--r-- | include/linux/coresight.h | 148 |
1 files changed, 57 insertions, 91 deletions
diff --git a/include/linux/coresight.h b/include/linux/coresight.h index a4cb7dd6ca2374..5f288d475490c9 100644 --- a/include/linux/coresight.h +++ b/include/linux/coresight.h @@ -35,7 +35,7 @@ #define CORESIGHT_UNLOCK 0xc5acce55 -extern struct bus_type coresight_bustype; +extern const struct bus_type coresight_bustype; enum coresight_dev_type { CORESIGHT_DEV_TYPE_SINK, @@ -226,13 +226,26 @@ struct coresight_sysfs_link { * by @coresight_ops. * @access: Device i/o access abstraction for this device. * @dev: The device entity associated to this component. - * @refcnt: keep track of what is in use. + * @mode: This tracer's mode, i.e sysFS, Perf or disabled. This is + * actually an 'enum cs_mode', but is stored in an atomic type. + * This is always accessed through local_read() and local_set(), + * but wherever it's done from within the Coresight device's lock, + * a non-atomic read would also work. This is the main point of + * synchronisation between code happening inside the sysfs mode's + * coresight_mutex and outside when running in Perf mode. A compare + * and exchange swap is done to atomically claim one mode or the + * other. + * @refcnt: keep track of what is in use. Only access this outside of the + * device's spinlock when the coresight_mutex held and mode == + * CS_MODE_SYSFS. Otherwise it must be accessed from inside the + * spinlock. * @orphan: true if the component has connections that haven't been linked. - * @enable: 'true' if component is currently part of an active path. - * @activated: 'true' only if a _sink_ has been activated. A sink can be - * activated but not yet enabled. Enabling for a _sink_ - * happens when a source has been selected and a path is enabled - * from source to that sink. + * @sysfs_sink_activated: 'true' when a sink has been selected for use via sysfs + * by writing a 1 to the 'enable_sink' file. A sink can be + * activated but not yet enabled. Enabling for a _sink_ happens + * when a source has been selected and a path is enabled from + * source to that sink. A sink can also become enabled but not + * activated if it's used via Perf. * @ea: Device attribute for sink representation under PMU directory. * @def_sink: cached reference to default sink found for this device. * @nr_links: number of sysfs links created to other components from this @@ -250,11 +263,11 @@ struct coresight_device { const struct coresight_ops *ops; struct csdev_access access; struct device dev; - atomic_t refcnt; + local_t mode; + int refcnt; bool orphan; - bool enable; /* true only if configured as part of a path */ /* sink specific fields */ - bool activated; /* true only if a sink is part of a path */ + bool sysfs_sink_activated; struct dev_ext_attribute *ea; struct coresight_device *def_sink; /* sysfs links between components */ @@ -378,8 +391,6 @@ struct coresight_ops { const struct coresight_ops_helper *helper_ops; }; -#if IS_ENABLED(CONFIG_CORESIGHT) - static inline u32 csdev_access_relaxed_read32(struct csdev_access *csa, u32 offset) { @@ -569,11 +580,43 @@ static inline bool coresight_is_percpu_sink(struct coresight_device *csdev) (csdev->subtype.sink_subtype == CORESIGHT_DEV_SUBTYPE_SINK_PERCPU_SYSMEM); } +/* + * Atomically try to take the device and set a new mode. Returns true on + * success, false if the device is already taken by someone else. + */ +static inline bool coresight_take_mode(struct coresight_device *csdev, + enum cs_mode new_mode) +{ + return local_cmpxchg(&csdev->mode, CS_MODE_DISABLED, new_mode) == + CS_MODE_DISABLED; +} + +static inline enum cs_mode coresight_get_mode(struct coresight_device *csdev) +{ + return local_read(&csdev->mode); +} + +static inline void coresight_set_mode(struct coresight_device *csdev, + enum cs_mode new_mode) +{ + enum cs_mode current_mode = coresight_get_mode(csdev); + + /* + * Changing to a new mode must be done from an already disabled state + * unless it's synchronized with coresight_take_mode(). Otherwise the + * device is already in use and signifies a locking issue. + */ + WARN(new_mode != CS_MODE_DISABLED && current_mode != CS_MODE_DISABLED && + current_mode != new_mode, "Device already in use\n"); + + local_set(&csdev->mode, new_mode); +} + extern struct coresight_device * coresight_register(struct coresight_desc *desc); extern void coresight_unregister(struct coresight_device *csdev); -extern int coresight_enable(struct coresight_device *csdev); -extern void coresight_disable(struct coresight_device *csdev); +extern int coresight_enable_sysfs(struct coresight_device *csdev); +extern void coresight_disable_sysfs(struct coresight_device *csdev); extern int coresight_timeout(struct csdev_access *csa, u32 offset, int position, int value); @@ -598,83 +641,6 @@ void coresight_relaxed_write64(struct coresight_device *csdev, u64 val, u32 offset); void coresight_write64(struct coresight_device *csdev, u64 val, u32 offset); -#else -static inline struct coresight_device * -coresight_register(struct coresight_desc *desc) { return NULL; } -static inline void coresight_unregister(struct coresight_device *csdev) {} -static inline int -coresight_enable(struct coresight_device *csdev) { return -ENOSYS; } -static inline void coresight_disable(struct coresight_device *csdev) {} - -static inline int coresight_timeout(struct csdev_access *csa, u32 offset, - int position, int value) -{ - return 1; -} - -static inline int coresight_claim_device_unlocked(struct coresight_device *csdev) -{ - return -EINVAL; -} - -static inline int coresight_claim_device(struct coresight_device *csdev) -{ - return -EINVAL; -} - -static inline void coresight_disclaim_device(struct coresight_device *csdev) {} -static inline void coresight_disclaim_device_unlocked(struct coresight_device *csdev) {} - -static inline bool coresight_loses_context_with_cpu(struct device *dev) -{ - return false; -} - -static inline u32 coresight_relaxed_read32(struct coresight_device *csdev, u32 offset) -{ - WARN_ON_ONCE(1); - return 0; -} - -static inline u32 coresight_read32(struct coresight_device *csdev, u32 offset) -{ - WARN_ON_ONCE(1); - return 0; -} - -static inline void coresight_write32(struct coresight_device *csdev, u32 val, u32 offset) -{ -} - -static inline void coresight_relaxed_write32(struct coresight_device *csdev, - u32 val, u32 offset) -{ -} - -static inline u64 coresight_relaxed_read64(struct coresight_device *csdev, - u32 offset) -{ - WARN_ON_ONCE(1); - return 0; -} - -static inline u64 coresight_read64(struct coresight_device *csdev, u32 offset) -{ - WARN_ON_ONCE(1); - return 0; -} - -static inline void coresight_relaxed_write64(struct coresight_device *csdev, - u64 val, u32 offset) -{ -} - -static inline void coresight_write64(struct coresight_device *csdev, u64 val, u32 offset) -{ -} - -#endif /* IS_ENABLED(CONFIG_CORESIGHT) */ - extern int coresight_get_cpu(struct device *dev); struct coresight_platform_data *coresight_get_platform_data(struct device *dev); |