// SPDX-License-Identifier: GPL-2.0-or-later /* * V4L2 controls framework uAPI implementation: * * Copyright (C) 2010-2021 Hans Verkuil <[email protected]> */ #define pr_fmt(fmt) … #include <linux/export.h> #include <linux/mm.h> #include <linux/slab.h> #include <media/v4l2-ctrls.h> #include <media/v4l2-dev.h> #include <media/v4l2-device.h> #include <media/v4l2-event.h> #include <media/v4l2-ioctl.h> #include "v4l2-ctrls-priv.h" /* Internal temporary helper struct, one for each v4l2_ext_control */ struct v4l2_ctrl_helper { … }; /* * Helper functions to copy control payload data from kernel space to * user space and vice versa. */ /* Helper function: copy the given control value back to the caller */ static int ptr_to_user(struct v4l2_ext_control *c, struct v4l2_ctrl *ctrl, union v4l2_ctrl_ptr ptr) { … } /* Helper function: copy the current control value back to the caller */ static int cur_to_user(struct v4l2_ext_control *c, struct v4l2_ctrl *ctrl) { … } /* Helper function: copy the new control value back to the caller */ static int new_to_user(struct v4l2_ext_control *c, struct v4l2_ctrl *ctrl) { … } /* Helper function: copy the request value back to the caller */ static int req_to_user(struct v4l2_ext_control *c, struct v4l2_ctrl_ref *ref) { … } /* Helper function: copy the initial control value back to the caller */ static int def_to_user(struct v4l2_ext_control *c, struct v4l2_ctrl *ctrl) { … } /* Helper function: copy the caller-provider value as the new control value */ static int user_to_new(struct v4l2_ext_control *c, struct v4l2_ctrl *ctrl) { … } /* * VIDIOC_G/TRY/S_EXT_CTRLS implementation */ /* * Some general notes on the atomic requirements of VIDIOC_G/TRY/S_EXT_CTRLS: * * It is not a fully atomic operation, just best-effort only. After all, if * multiple controls have to be set through multiple i2c writes (for example) * then some initial writes may succeed while others fail. Thus leaving the * system in an inconsistent state. The question is how much effort you are * willing to spend on trying to make something atomic that really isn't. * * From the point of view of an application the main requirement is that * when you call VIDIOC_S_EXT_CTRLS and some values are invalid then an * error should be returned without actually affecting any controls. * * If all the values are correct, then it is acceptable to just give up * in case of low-level errors. * * It is important though that the application can tell when only a partial * configuration was done. The way we do that is through the error_idx field * of struct v4l2_ext_controls: if that is equal to the count field then no * controls were affected. Otherwise all controls before that index were * successful in performing their 'get' or 'set' operation, the control at * the given index failed, and you don't know what happened with the controls * after the failed one. Since if they were part of a control cluster they * could have been successfully processed (if a cluster member was encountered * at index < error_idx), they could have failed (if a cluster member was at * error_idx), or they may not have been processed yet (if the first cluster * member appeared after error_idx). * * It is all fairly theoretical, though. In practice all you can do is to * bail out. If error_idx == count, then it is an application bug. If * error_idx < count then it is only an application bug if the error code was * EBUSY. That usually means that something started streaming just when you * tried to set the controls. In all other cases it is a driver/hardware * problem and all you can do is to retry or bail out. * * Note that these rules do not apply to VIDIOC_TRY_EXT_CTRLS: since that * never modifies controls the error_idx is just set to whatever control * has an invalid value. */ /* * Prepare for the extended g/s/try functions. * Find the controls in the control array and do some basic checks. */ static int prepare_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *cs, struct v4l2_ctrl_helper *helpers, struct video_device *vdev, bool get) { … } /* * Handles the corner case where cs->count == 0. It checks whether the * specified control class exists. If that class ID is 0, then it checks * whether there are any controls at all. */ static int class_check(struct v4l2_ctrl_handler *hdl, u32 which) { … } /* * Get extended controls. Allocates the helpers array if needed. * * Note that v4l2_g_ext_ctrls_common() with 'which' set to * V4L2_CTRL_WHICH_REQUEST_VAL is only called if the request was * completed, and in that case p_req_valid is true for all controls. */ int v4l2_g_ext_ctrls_common(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *cs, struct video_device *vdev) { … } int v4l2_g_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct video_device *vdev, struct media_device *mdev, struct v4l2_ext_controls *cs) { … } EXPORT_SYMBOL(…); /* Validate a new control */ static int validate_new(const struct v4l2_ctrl *ctrl, union v4l2_ctrl_ptr p_new) { … } /* Validate controls. */ static int validate_ctrls(struct v4l2_ext_controls *cs, struct v4l2_ctrl_helper *helpers, struct video_device *vdev, bool set) { … } /* Try or try-and-set controls */ int try_set_ext_ctrls_common(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *cs, struct video_device *vdev, bool set) { … } static int try_set_ext_ctrls(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl, struct video_device *vdev, struct media_device *mdev, struct v4l2_ext_controls *cs, bool set) { … } int v4l2_try_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct video_device *vdev, struct media_device *mdev, struct v4l2_ext_controls *cs) { … } EXPORT_SYMBOL(…); int v4l2_s_ext_ctrls(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl, struct video_device *vdev, struct media_device *mdev, struct v4l2_ext_controls *cs) { … } EXPORT_SYMBOL(…); /* * VIDIOC_G/S_CTRL implementation */ /* Helper function to get a single control */ static int get_ctrl(struct v4l2_ctrl *ctrl, struct v4l2_ext_control *c) { … } int v4l2_g_ctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_control *control) { … } EXPORT_SYMBOL(…); /* Helper function for VIDIOC_S_CTRL compatibility */ static int set_ctrl(struct v4l2_fh *fh, struct v4l2_ctrl *ctrl, u32 ch_flags) { … } /* Helper function for VIDIOC_S_CTRL compatibility */ static int set_ctrl_lock(struct v4l2_fh *fh, struct v4l2_ctrl *ctrl, struct v4l2_ext_control *c) { … } int v4l2_s_ctrl(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl, struct v4l2_control *control) { … } EXPORT_SYMBOL(…); /* * Helper functions for drivers to get/set controls. */ s32 v4l2_ctrl_g_ctrl(struct v4l2_ctrl *ctrl) { … } EXPORT_SYMBOL(…); s64 v4l2_ctrl_g_ctrl_int64(struct v4l2_ctrl *ctrl) { … } EXPORT_SYMBOL(…); int __v4l2_ctrl_s_ctrl(struct v4l2_ctrl *ctrl, s32 val) { … } EXPORT_SYMBOL(…); int __v4l2_ctrl_s_ctrl_int64(struct v4l2_ctrl *ctrl, s64 val) { … } EXPORT_SYMBOL(…); int __v4l2_ctrl_s_ctrl_string(struct v4l2_ctrl *ctrl, const char *s) { … } EXPORT_SYMBOL(…); int __v4l2_ctrl_s_ctrl_compound(struct v4l2_ctrl *ctrl, enum v4l2_ctrl_type type, const void *p) { … } EXPORT_SYMBOL(…); /* * Modify the range of a control. */ int __v4l2_ctrl_modify_range(struct v4l2_ctrl *ctrl, s64 min, s64 max, u64 step, s64 def) { … } EXPORT_SYMBOL(…); int __v4l2_ctrl_modify_dimensions(struct v4l2_ctrl *ctrl, u32 dims[V4L2_CTRL_MAX_DIMS]) { … } EXPORT_SYMBOL(…); /* Implement VIDIOC_QUERY_EXT_CTRL */ int v4l2_query_ext_ctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_query_ext_ctrl *qc) { … } EXPORT_SYMBOL(…); /* Implement VIDIOC_QUERYCTRL */ int v4l2_queryctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_queryctrl *qc) { … } EXPORT_SYMBOL(…); /* Implement VIDIOC_QUERYMENU */ int v4l2_querymenu(struct v4l2_ctrl_handler *hdl, struct v4l2_querymenu *qm) { … } EXPORT_SYMBOL(…); /* * VIDIOC_LOG_STATUS helpers */ int v4l2_ctrl_log_status(struct file *file, void *fh) { … } EXPORT_SYMBOL(…); int v4l2_ctrl_subdev_log_status(struct v4l2_subdev *sd) { … } EXPORT_SYMBOL(…); /* * VIDIOC_(UN)SUBSCRIBE_EVENT implementation */ static int v4l2_ctrl_add_event(struct v4l2_subscribed_event *sev, unsigned int elems) { … } static void v4l2_ctrl_del_event(struct v4l2_subscribed_event *sev) { … } void v4l2_ctrl_replace(struct v4l2_event *old, const struct v4l2_event *new) { … } EXPORT_SYMBOL(…); void v4l2_ctrl_merge(const struct v4l2_event *old, struct v4l2_event *new) { … } EXPORT_SYMBOL(…); const struct v4l2_subscribed_event_ops v4l2_ctrl_sub_ev_ops = …; EXPORT_SYMBOL(…); int v4l2_ctrl_subscribe_event(struct v4l2_fh *fh, const struct v4l2_event_subscription *sub) { … } EXPORT_SYMBOL(…); int v4l2_ctrl_subdev_subscribe_event(struct v4l2_subdev *sd, struct v4l2_fh *fh, struct v4l2_event_subscription *sub) { … } EXPORT_SYMBOL(…); /* * poll helper */ __poll_t v4l2_ctrl_poll(struct file *file, struct poll_table_struct *wait) { … } EXPORT_SYMBOL(…);
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