diff options
Diffstat (limited to 'include/media/v4l2-subdev.h')
| -rw-r--r-- | include/media/v4l2-subdev.h | 133 |
1 files changed, 127 insertions, 6 deletions
diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h index eab8e4342613..f967c27e41c3 100644 --- a/include/media/v4l2-subdev.h +++ b/include/media/v4l2-subdev.h @@ -658,6 +658,8 @@ struct v4l2_subdev_pad_config { /** * struct v4l2_subdev_state - Used for storing subdev state information. * + * @_lock: default for 'lock' + * @lock: mutex for the state. May be replaced by the user. * @pads: &struct v4l2_subdev_pad_config array * * This structure only needs to be passed to the pad op if the 'which' field @@ -665,6 +667,9 @@ struct v4l2_subdev_pad_config { * %V4L2_SUBDEV_FORMAT_ACTIVE it is safe to pass %NULL. */ struct v4l2_subdev_state { + /* lock for the struct v4l2_subdev_state fields */ + struct mutex _lock; + struct mutex *lock; struct v4l2_subdev_pad_config *pads; }; @@ -888,6 +893,9 @@ struct v4l2_subdev_platform_data { * @subdev_notifier: A sub-device notifier implicitly registered for the sub- * device using v4l2_async_register_subdev_sensor(). * @pdata: common part of subdevice platform data + * @state_lock: A pointer to a lock used for all the subdev's states, set by the + * driver. This is optional. If NULL, each state instance will get + * a lock of its own. * @active_state: Active state for the subdev (NULL for subdevs tracking the * state internally). Initialized by calling * v4l2_subdev_init_finalize(). @@ -922,6 +930,7 @@ struct v4l2_subdev { struct v4l2_async_notifier *notifier; struct v4l2_async_notifier *subdev_notifier; struct v4l2_subdev_platform_data *pdata; + struct mutex *state_lock; /* * The fields below are private, and should only be accessed via @@ -1157,12 +1166,16 @@ int v4l2_subdev_link_validate(struct media_link *link); * __v4l2_subdev_state_alloc - allocate v4l2_subdev_state * * @sd: pointer to &struct v4l2_subdev for which the state is being allocated. + * @lock_name: name of the state lock + * @key: lock_class_key for the lock * * Must call __v4l2_subdev_state_free() when state is no longer needed. * * Not to be called directly by the drivers. */ -struct v4l2_subdev_state *__v4l2_subdev_state_alloc(struct v4l2_subdev *sd); +struct v4l2_subdev_state *__v4l2_subdev_state_alloc(struct v4l2_subdev *sd, + const char *lock_name, + struct lock_class_key *key); /** * __v4l2_subdev_state_free - free a v4l2_subdev_state @@ -1187,7 +1200,16 @@ void __v4l2_subdev_state_free(struct v4l2_subdev_state *state); * * The user must call v4l2_subdev_cleanup() when the subdev is being removed. */ -int v4l2_subdev_init_finalize(struct v4l2_subdev *sd); +#define v4l2_subdev_init_finalize(sd) \ + ({ \ + static struct lock_class_key __key; \ + const char *name = KBUILD_BASENAME \ + ":" __stringify(__LINE__) ":sd->active_state->lock"; \ + __v4l2_subdev_init_finalize(sd, name, &__key); \ + }) + +int __v4l2_subdev_init_finalize(struct v4l2_subdev *sd, const char *name, + struct lock_class_key *key); /** * v4l2_subdev_cleanup() - Releases the resources allocated by the subdevice @@ -1199,16 +1221,85 @@ int v4l2_subdev_init_finalize(struct v4l2_subdev *sd); void v4l2_subdev_cleanup(struct v4l2_subdev *sd); /** - * v4l2_subdev_get_active_state() - Returns the active subdev state for - * subdevice + * v4l2_subdev_lock_state() - Locks the subdev state + * @state: The subdevice state + * + * Locks the given subdev state. + * + * The state must be unlocked with v4l2_subdev_unlock_state() after use. + */ +static inline void v4l2_subdev_lock_state(struct v4l2_subdev_state *state) +{ + mutex_lock(state->lock); +} + +/** + * v4l2_subdev_unlock_state() - Unlocks the subdev state + * @state: The subdevice state + * + * Unlocks the given subdev state. + */ +static inline void v4l2_subdev_unlock_state(struct v4l2_subdev_state *state) +{ + mutex_unlock(state->lock); +} + +/** + * v4l2_subdev_get_unlocked_active_state() - Checks that the active subdev state + * is unlocked and returns it + * @sd: The subdevice + * + * Returns the active state for the subdevice, or NULL if the subdev does not + * support active state. If the state is not NULL, calls + * lockdep_assert_not_held() to issue a warning if the state is locked. + * + * This function is to be used e.g. when getting the active state for the sole + * purpose of passing it forward, without accessing the state fields. + */ +static inline struct v4l2_subdev_state * +v4l2_subdev_get_unlocked_active_state(struct v4l2_subdev *sd) +{ + if (sd->active_state) + lockdep_assert_not_held(sd->active_state->lock); + return sd->active_state; +} + +/** + * v4l2_subdev_get_locked_active_state() - Checks that the active subdev state + * is locked and returns it + * * @sd: The subdevice * * Returns the active state for the subdevice, or NULL if the subdev does not - * support active state. + * support active state. If the state is not NULL, calls lockdep_assert_held() + * to issue a warning if the state is not locked. + * + * This function is to be used when the caller knows that the active state is + * already locked. + */ +static inline struct v4l2_subdev_state * +v4l2_subdev_get_locked_active_state(struct v4l2_subdev *sd) +{ + if (sd->active_state) + lockdep_assert_held(sd->active_state->lock); + return sd->active_state; +} + +/** + * v4l2_subdev_lock_and_get_active_state() - Locks and returns the active subdev + * state for the subdevice + * @sd: The subdevice + * + * Returns the locked active state for the subdevice, or NULL if the subdev + * does not support active state. + * + * The state must be unlocked with v4l2_subdev_unlock_state() after use. */ static inline struct v4l2_subdev_state * -v4l2_subdev_get_active_state(struct v4l2_subdev *sd) +v4l2_subdev_lock_and_get_active_state(struct v4l2_subdev *sd) { + if (sd->active_state) + v4l2_subdev_lock_state(sd->active_state); return sd->active_state; } @@ -1256,6 +1347,36 @@ extern const struct v4l2_subdev_ops v4l2_subdev_call_wrappers; }) /** + * v4l2_subdev_call_state_active - call an operation of a v4l2_subdev which + * takes state as a parameter, passing the + * subdev its active state. + * + * @sd: pointer to the &struct v4l2_subdev + * @o: name of the element at &struct v4l2_subdev_ops that contains @f. + * Each element there groups a set of callbacks functions. + * @f: callback function to be called. + * The callback functions are defined in groups, according to + * each element at &struct v4l2_subdev_ops. + * @args: arguments for @f. + * + * This is similar to v4l2_subdev_call(), except that this version can only be + * used for ops that take a subdev state as a parameter. The macro will get the + * active state, lock it before calling the op and unlock it after the call. + */ +#define v4l2_subdev_call_state_active(sd, o, f, args...) \ + ({ \ + int __result; \ + struct v4l2_subdev_state *state; \ + state = v4l2_subdev_get_unlocked_active_state(sd); \ + if (state) \ + v4l2_subdev_lock_state(state); \ + __result = v4l2_subdev_call(sd, o, f, state, ##args); \ + if (state) \ + v4l2_subdev_unlock_state(state); \ + __result; \ + }) + +/** * v4l2_subdev_has_op - Checks if a subdev defines a certain operation. * * @sd: pointer to the &struct v4l2_subdev |