// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * V4L2 controls framework uAPI implementation:
 *
 * Copyright (C) 2010-2021  Hans Verkuil <hverkuil-cisco@xs4all.nl>
 */

#define pr_fmt(fmt) "v4l2-ctrls: " 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 {
        /* Pointer to the control reference of the master control */
        struct v4l2_ctrl_ref *mref;
        /* The control ref corresponding to the v4l2_ext_control ID field. */
        struct v4l2_ctrl_ref *ref;
        /*
         * v4l2_ext_control index of the next control belonging to the
         * same cluster, or 0 if there isn't any.
         */
        u32 next;
};

/*
 * 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)
{
        u32 len;

        if (ctrl->is_ptr && !ctrl->is_string)
                return copy_to_user(c->ptr, ptr.p_const, c->size) ?
                       -EFAULT : 0;

        switch (ctrl->type) {
        case V4L2_CTRL_TYPE_STRING:
                len = strlen(ptr.p_char);
                if (c->size < len + 1) {
                        c->size = ctrl->elem_size;
                        return -ENOSPC;
                }
                return copy_to_user(c->string, ptr.p_char, len + 1) ?
                       -EFAULT : 0;
        case V4L2_CTRL_TYPE_INTEGER64:
                c->value64 = *ptr.p_s64;
                break;
        default:
                c->value = *ptr.p_s32;
                break;
        }
        return 0;
}

/* 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)
{
        return ptr_to_user(c, ctrl, ctrl->p_cur);
}

/* 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)
{
        return ptr_to_user(c, ctrl, ctrl->p_new);
}

/* 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)
{
        return ptr_to_user(c, ref->ctrl, ref->p_req);
}

/* 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)
{
        int idx;

        for (idx = 0; idx < ctrl->elems; idx++)
                ctrl->type_ops->init(ctrl, idx, ctrl->p_new);

        return ptr_to_user(c, ctrl, ctrl->p_new);
}

/* Helper function: copy the caller-provider value to the given control value */
static int user_to_ptr(struct v4l2_ext_control *c,
                       struct v4l2_ctrl *ctrl,
                       union v4l2_ctrl_ptr ptr)
{
        int ret;
        u32 size;

        ctrl->is_new = 1;
        if (ctrl->is_ptr && !ctrl->is_string) {
                unsigned int idx;

                ret = copy_from_user(ptr.p, c->ptr, c->size) ? -EFAULT : 0;
                if (ret || !ctrl->is_array)
                        return ret;
                for (idx = c->size / ctrl->elem_size; idx < ctrl->elems; idx++)
                        ctrl->type_ops->init(ctrl, idx, ptr);
                return 0;
        }

        switch (ctrl->type) {
        case V4L2_CTRL_TYPE_INTEGER64:
                *ptr.p_s64 = c->value64;
                break;
        case V4L2_CTRL_TYPE_STRING:
                size = c->size;
                if (size == 0)
                        return -ERANGE;
                if (size > ctrl->maximum + 1)
                        size = ctrl->maximum + 1;
                ret = copy_from_user(ptr.p_char, c->string, size) ? -EFAULT : 0;
                if (!ret) {
                        char last = ptr.p_char[size - 1];

                        ptr.p_char[size - 1] = 0;
                        /*
                         * If the string was longer than ctrl->maximum,
                         * then return an error.
                         */
                        if (strlen(ptr.p_char) == ctrl->maximum && last)
                                return -ERANGE;
                }
                return ret;
        default:
                *ptr.p_s32 = c->value;
                break;
        }
        return 0;
}

/* 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)
{
        return user_to_ptr(c, ctrl, ctrl->p_new);
}

/*
 * 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)
{
        struct v4l2_ctrl_helper *h;
        bool have_clusters = false;
        u32 i;

        for (i = 0, h = helpers; i < cs->count; i++, h++) {
                struct v4l2_ext_control *c = &cs->controls[i];
                struct v4l2_ctrl_ref *ref;
                struct v4l2_ctrl *ctrl;
                u32 id = c->id & V4L2_CTRL_ID_MASK;

                cs->error_idx = i;

                if (cs->which &&
                    cs->which != V4L2_CTRL_WHICH_DEF_VAL &&
                    cs->which != V4L2_CTRL_WHICH_REQUEST_VAL &&
                    V4L2_CTRL_ID2WHICH(id) != cs->which) {
                        dprintk(vdev,
                                "invalid which 0x%x or control id 0x%x\n",
                                cs->which, id);
                        return -EINVAL;
                }

                /*
                 * Old-style private controls are not allowed for
                 * extended controls.
                 */
                if (id >= V4L2_CID_PRIVATE_BASE) {
                        dprintk(vdev,
                                "old-style private controls not allowed\n");
                        return -EINVAL;
                }
                ref = find_ref_lock(hdl, id);
                if (!ref) {
                        dprintk(vdev, "cannot find control id 0x%x\n", id);
                        return -EINVAL;
                }
                h->ref = ref;
                ctrl = ref->ctrl;
                if (ctrl->flags & V4L2_CTRL_FLAG_DISABLED) {
                        dprintk(vdev, "control id 0x%x is disabled\n", id);
                        return -EINVAL;
                }

                if (ctrl->cluster[0]->ncontrols > 1)
                        have_clusters = true;
                if (ctrl->cluster[0] != ctrl)
                        ref = find_ref_lock(hdl, ctrl->cluster[0]->id);
                if (ctrl->is_ptr && !ctrl->is_string) {
                        unsigned int tot_size = ctrl->elems * ctrl->elem_size;

                        if (c->size < tot_size) {
                                /*
                                 * In the get case the application first
                                 * queries to obtain the size of the control.
                                 */
                                if (get) {
                                        c->size = tot_size;
                                        return -ENOSPC;
                                }
                                dprintk(vdev,
                                        "pointer control id 0x%x size too small, %d bytes but %d bytes needed\n",
                                        id, c->size, tot_size);
                                return -EFAULT;
                        }
                        c->size = tot_size;
                }
                /* Store the ref to the master control of the cluster */
                h->mref = ref;
                /*
                 * Initially set next to 0, meaning that there is no other
                 * control in this helper array belonging to the same
                 * cluster.
                 */
                h->next = 0;
        }

        /*
         * We are done if there were no controls that belong to a multi-
         * control cluster.
         */
        if (!have_clusters)
                return 0;

        /*
         * The code below figures out in O(n) time which controls in the list
         * belong to the same cluster.
         */

        /* This has to be done with the handler lock taken. */
        mutex_lock(hdl->lock);

        /* First zero the helper field in the master control references */
        for (i = 0; i < cs->count; i++)
                helpers[i].mref->helper = NULL;
        for (i = 0, h = helpers; i < cs->count; i++, h++) {
                struct v4l2_ctrl_ref *mref = h->mref;

                /*
                 * If the mref->helper is set, then it points to an earlier
                 * helper that belongs to the same cluster.
                 */
                if (mref->helper) {
                        /*
                         * Set the next field of mref->helper to the current
                         * index: this means that the earlier helper now
                         * points to the next helper in the same cluster.
                         */
                        mref->helper->next = i;
                        /*
                         * mref should be set only for the first helper in the
                         * cluster, clear the others.
                         */
                        h->mref = NULL;
                }
                /* Point the mref helper to the current helper struct. */
                mref->helper = h;
        }
        mutex_unlock(hdl->lock);
        return 0;
}

/*
 * 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)
{
        if (which == 0 || which == V4L2_CTRL_WHICH_DEF_VAL ||
            which == V4L2_CTRL_WHICH_REQUEST_VAL)
                return 0;
        return find_ref_lock(hdl, which | 1) ? 0 : -EINVAL;
}

/*
 * 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 valid_p_req 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)
{
        struct v4l2_ctrl_helper helper[4];
        struct v4l2_ctrl_helper *helpers = helper;
        int ret;
        int i, j;
        bool is_default, is_request;

        is_default = (cs->which == V4L2_CTRL_WHICH_DEF_VAL);
        is_request = (cs->which == V4L2_CTRL_WHICH_REQUEST_VAL);

        cs->error_idx = cs->count;
        cs->which = V4L2_CTRL_ID2WHICH(cs->which);

        if (!hdl)
                return -EINVAL;

        if (cs->count == 0)
                return class_check(hdl, cs->which);

        if (cs->count > ARRAY_SIZE(helper)) {
                helpers = kvmalloc_array(cs->count, sizeof(helper[0]),
                                         GFP_KERNEL);
                if (!helpers)
                        return -ENOMEM;
        }

        ret = prepare_ext_ctrls(hdl, cs, helpers, vdev, true);
        cs->error_idx = cs->count;

        for (i = 0; !ret && i < cs->count; i++)
                if (helpers[i].ref->ctrl->flags & V4L2_CTRL_FLAG_WRITE_ONLY)
                        ret = -EACCES;

        for (i = 0; !ret && i < cs->count; i++) {
                struct v4l2_ctrl *master;
                bool is_volatile = false;
                u32 idx = i;

                if (!helpers[i].mref)
                        continue;

                master = helpers[i].mref->ctrl;
                cs->error_idx = i;

                v4l2_ctrl_lock(master);

                /*
                 * g_volatile_ctrl will update the new control values.
                 * This makes no sense for V4L2_CTRL_WHICH_DEF_VAL and
                 * V4L2_CTRL_WHICH_REQUEST_VAL. In the case of requests
                 * it is v4l2_ctrl_request_complete() that copies the
                 * volatile controls at the time of request completion
                 * to the request, so you don't want to do that again.
                 */
                if (!is_default && !is_request &&
                    ((master->flags & V4L2_CTRL_FLAG_VOLATILE) ||
                    (master->has_volatiles && !is_cur_manual(master)))) {
                        for (j = 0; j < master->ncontrols; j++)
                                cur_to_new(master->cluster[j]);
                        ret = call_op(master, g_volatile_ctrl);
                        is_volatile = true;
                }

                if (ret) {
                        v4l2_ctrl_unlock(master);
                        break;
                }

                /*
                 * Copy the default value (if is_default is true), the
                 * request value (if is_request is true and p_req is valid),
                 * the new volatile value (if is_volatile is true) or the
                 * current value.
                 */
                do {
                        struct v4l2_ctrl_ref *ref = helpers[idx].ref;

                        if (is_default)
                                ret = def_to_user(cs->controls + idx, ref->ctrl);
                        else if (is_request && ref->valid_p_req)
                                ret = req_to_user(cs->controls + idx, ref);
                        else if (is_volatile)
                                ret = new_to_user(cs->controls + idx, ref->ctrl);
                        else
                                ret = cur_to_user(cs->controls + idx, ref->ctrl);
                        idx = helpers[idx].next;
                } while (!ret && idx);

                v4l2_ctrl_unlock(master);
        }

        if (cs->count > ARRAY_SIZE(helper))
                kvfree(helpers);
        return ret;
}

int v4l2_g_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct video_device *vdev,
                     struct media_device *mdev, struct v4l2_ext_controls *cs)
{
        if (cs->which == V4L2_CTRL_WHICH_REQUEST_VAL)
                return v4l2_g_ext_ctrls_request(hdl, vdev, mdev, cs);

        return v4l2_g_ext_ctrls_common(hdl, cs, vdev);
}
EXPORT_SYMBOL(v4l2_g_ext_ctrls);

/* Validate controls. */
static int validate_ctrls(struct v4l2_ext_controls *cs,
                          struct v4l2_ctrl_helper *helpers,
                          struct video_device *vdev,
                          bool set)
{
        unsigned int i;
        int ret = 0;

        cs->error_idx = cs->count;
        for (i = 0; i < cs->count; i++) {
                struct v4l2_ctrl *ctrl = helpers[i].ref->ctrl;
                union v4l2_ctrl_ptr p_new;

                cs->error_idx = i;

                if (ctrl->flags & V4L2_CTRL_FLAG_READ_ONLY) {
                        dprintk(vdev,
                                "control id 0x%x is read-only\n",
                                ctrl->id);
                        return -EACCES;
                }
                /*
                 * This test is also done in try_set_control_cluster() which
                 * is called in atomic context, so that has the final say,
                 * but it makes sense to do an up-front check as well. Once
                 * an error occurs in try_set_control_cluster() some other
                 * controls may have been set already and we want to do a
                 * best-effort to avoid that.
                 */
                if (set && (ctrl->flags & V4L2_CTRL_FLAG_GRABBED)) {
                        dprintk(vdev,
                                "control id 0x%x is grabbed, cannot set\n",
                                ctrl->id);
                        return -EBUSY;
                }
                /*
                 * Skip validation for now if the payload needs to be copied
                 * from userspace into kernelspace. We'll validate those later.
                 */
                if (ctrl->is_ptr)
                        continue;
                if (ctrl->type == V4L2_CTRL_TYPE_INTEGER64)
                        p_new.p_s64 = &cs->controls[i].value64;
                else
                        p_new.p_s32 = &cs->controls[i].value;
                ret = validate_new(ctrl, p_new);
                if (ret)
                        return ret;
        }
        return 0;
}

/* 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)
{
        struct v4l2_ctrl_helper helper[4];
        struct v4l2_ctrl_helper *helpers = helper;
        unsigned int i, j;
        int ret;

        cs->error_idx = cs->count;

        /* Default value cannot be changed */
        if (cs->which == V4L2_CTRL_WHICH_DEF_VAL) {
                dprintk(vdev, "%s: cannot change default value\n",
                        video_device_node_name(vdev));
                return -EINVAL;
        }

        cs->which = V4L2_CTRL_ID2WHICH(cs->which);

        if (!hdl) {
                dprintk(vdev, "%s: invalid null control handler\n",
                        video_device_node_name(vdev));
                return -EINVAL;
        }

        if (cs->count == 0)
                return class_check(hdl, cs->which);

        if (cs->count > ARRAY_SIZE(helper)) {
                helpers = kvmalloc_array(cs->count, sizeof(helper[0]),
                                         GFP_KERNEL);
                if (!helpers)
                        return -ENOMEM;
        }
        ret = prepare_ext_ctrls(hdl, cs, helpers, vdev, false);
        if (!ret)
                ret = validate_ctrls(cs, helpers, vdev, set);
        if (ret && set)
                cs->error_idx = cs->count;
        for (i = 0; !ret && i < cs->count; i++) {
                struct v4l2_ctrl *master;
                u32 idx = i;

                if (!helpers[i].mref)
                        continue;

                cs->error_idx = i;
                master = helpers[i].mref->ctrl;
                v4l2_ctrl_lock(master);

                /* Reset the 'is_new' flags of the cluster */
                for (j = 0; j < master->ncontrols; j++)
                        if (master->cluster[j])
                                master->cluster[j]->is_new = 0;

                /*
                 * For volatile autoclusters that are currently in auto mode
                 * we need to discover if it will be set to manual mode.
                 * If so, then we have to copy the current volatile values
                 * first since those will become the new manual values (which
                 * may be overwritten by explicit new values from this set
                 * of controls).
                 */
                if (master->is_auto && master->has_volatiles &&
                    !is_cur_manual(master)) {
                        /* Pick an initial non-manual value */
                        s32 new_auto_val = master->manual_mode_value + 1;
                        u32 tmp_idx = idx;

                        do {
                                /*
                                 * Check if the auto control is part of the
                                 * list, and remember the new value.
                                 */
                                if (helpers[tmp_idx].ref->ctrl == master)
                                        new_auto_val = cs->controls[tmp_idx].value;
                                tmp_idx = helpers[tmp_idx].next;
                        } while (tmp_idx);
                        /*
                         * If the new value == the manual value, then copy
                         * the current volatile values.
                         */
                        if (new_auto_val == master->manual_mode_value)
                                update_from_auto_cluster(master);
                }

                /*
                 * Copy the new caller-supplied control values.
                 * user_to_new() sets 'is_new' to 1.
                 */
                do {
                        struct v4l2_ctrl *ctrl = helpers[idx].ref->ctrl;

                        ret = user_to_new(cs->controls + idx, ctrl);
                        if (!ret && ctrl->is_ptr) {
                                ret = validate_new(ctrl, ctrl->p_new);
                                if (ret)
                                        dprintk(vdev,
                                                "failed to validate control %s (%d)\n",
                                                v4l2_ctrl_get_name(ctrl->id), ret);
                        }
                        idx = helpers[idx].next;
                } while (!ret && idx);

                if (!ret)
                        ret = try_or_set_cluster(fh, master,
                                                 !hdl->req_obj.req && set, 0);
                if (!ret && hdl->req_obj.req && set) {
                        for (j = 0; j < master->ncontrols; j++) {
                                struct v4l2_ctrl_ref *ref =
                                        find_ref(hdl, master->cluster[j]->id);

                                new_to_req(ref);
                        }
                }

                /* Copy the new values back to userspace. */
                if (!ret) {
                        idx = i;
                        do {
                                ret = new_to_user(cs->controls + idx,
                                                  helpers[idx].ref->ctrl);
                                idx = helpers[idx].next;
                        } while (!ret && idx);
                }
                v4l2_ctrl_unlock(master);
        }

        if (cs->count > ARRAY_SIZE(helper))
                kvfree(helpers);
        return ret;
}

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 ret;

        if (cs->which == V4L2_CTRL_WHICH_REQUEST_VAL)
                return try_set_ext_ctrls_request(fh, hdl, vdev, mdev, cs, set);

        ret = try_set_ext_ctrls_common(fh, hdl, cs, vdev, set);
        if (ret)
                dprintk(vdev,
                        "%s: try_set_ext_ctrls_common failed (%d)\n",
                        video_device_node_name(vdev), ret);

        return ret;
}

int v4l2_try_ext_ctrls(struct v4l2_ctrl_handler *hdl,
                       struct video_device *vdev,
                       struct media_device *mdev,
                       struct v4l2_ext_controls *cs)
{
        return try_set_ext_ctrls(NULL, hdl, vdev, mdev, cs, false);
}
EXPORT_SYMBOL(v4l2_try_ext_ctrls);

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)
{
        return try_set_ext_ctrls(fh, hdl, vdev, mdev, cs, true);
}
EXPORT_SYMBOL(v4l2_s_ext_ctrls);

/*
 * 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)
{
        struct v4l2_ctrl *master = ctrl->cluster[0];
        int ret = 0;
        int i;

        /* Compound controls are not supported. The new_to_user() and
         * cur_to_user() calls below would need to be modified not to access
         * userspace memory when called from get_ctrl().
         */
        if (!ctrl->is_int && ctrl->type != V4L2_CTRL_TYPE_INTEGER64)
                return -EINVAL;

        if (ctrl->flags & V4L2_CTRL_FLAG_WRITE_ONLY)
                return -EACCES;

        v4l2_ctrl_lock(master);
        /* g_volatile_ctrl will update the current control values */
        if (ctrl->flags & V4L2_CTRL_FLAG_VOLATILE) {
                for (i = 0; i < master->ncontrols; i++)
                        cur_to_new(master->cluster[i]);
                ret = call_op(master, g_volatile_ctrl);
                new_to_user(c, ctrl);
        } else {
                cur_to_user(c, ctrl);
        }
        v4l2_ctrl_unlock(master);
        return ret;
}

int v4l2_g_ctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_control *control)
{
        struct v4l2_ctrl *ctrl = v4l2_ctrl_find(hdl, control->id);
        struct v4l2_ext_control c;
        int ret;

        if (!ctrl || !ctrl->is_int)
                return -EINVAL;
        ret = get_ctrl(ctrl, &c);
        control->value = c.value;
        return ret;
}
EXPORT_SYMBOL(v4l2_g_ctrl);

/* Helper function for VIDIOC_S_CTRL compatibility */
static int set_ctrl(struct v4l2_fh *fh, struct v4l2_ctrl *ctrl, u32 ch_flags)
{
        struct v4l2_ctrl *master = ctrl->cluster[0];
        int ret;
        int i;

        /* Reset the 'is_new' flags of the cluster */
        for (i = 0; i < master->ncontrols; i++)
                if (master->cluster[i])
                        master->cluster[i]->is_new = 0;

        ret = validate_new(ctrl, ctrl->p_new);
        if (ret)
                return ret;

        /*
         * For autoclusters with volatiles that are switched from auto to
         * manual mode we have to update the current volatile values since
         * those will become the initial manual values after such a switch.
         */
        if (master->is_auto && master->has_volatiles && ctrl == master &&
            !is_cur_manual(master) && ctrl->val == master->manual_mode_value)
                update_from_auto_cluster(master);

        ctrl->is_new = 1;
        return try_or_set_cluster(fh, master, true, 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 ret;

        v4l2_ctrl_lock(ctrl);
        user_to_new(c, ctrl);
        ret = set_ctrl(fh, ctrl, 0);
        if (!ret)
                cur_to_user(c, ctrl);
        v4l2_ctrl_unlock(ctrl);
        return ret;
}

int v4l2_s_ctrl(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl,
                struct v4l2_control *control)
{
        struct v4l2_ctrl *ctrl = v4l2_ctrl_find(hdl, control->id);
        struct v4l2_ext_control c = { control->id };
        int ret;

        if (!ctrl || !ctrl->is_int)
                return -EINVAL;

        if (ctrl->flags & V4L2_CTRL_FLAG_READ_ONLY)
                return -EACCES;

        c.value = control->value;
        ret = set_ctrl_lock(fh, ctrl, &c);
        control->value = c.value;
        return ret;
}
EXPORT_SYMBOL(v4l2_s_ctrl);

/*
 * Helper functions for drivers to get/set controls.
 */

s32 v4l2_ctrl_g_ctrl(struct v4l2_ctrl *ctrl)
{
        struct v4l2_ext_control c;

        /* It's a driver bug if this happens. */
        if (WARN_ON(!ctrl->is_int))
                return 0;
        c.value = 0;
        get_ctrl(ctrl, &c);
        return c.value;
}
EXPORT_SYMBOL(v4l2_ctrl_g_ctrl);

s64 v4l2_ctrl_g_ctrl_int64(struct v4l2_ctrl *ctrl)
{
        struct v4l2_ext_control c;

        /* It's a driver bug if this happens. */
        if (WARN_ON(ctrl->is_ptr || ctrl->type != V4L2_CTRL_TYPE_INTEGER64))
                return 0;
        c.value64 = 0;
        get_ctrl(ctrl, &c);
        return c.value64;
}
EXPORT_SYMBOL(v4l2_ctrl_g_ctrl_int64);

int __v4l2_ctrl_s_ctrl(struct v4l2_ctrl *ctrl, s32 val)
{
        lockdep_assert_held(ctrl->handler->lock);

        /* It's a driver bug if this happens. */
        if (WARN_ON(!ctrl->is_int))
                return -EINVAL;
        ctrl->val = val;
        return set_ctrl(NULL, ctrl, 0);
}
EXPORT_SYMBOL(__v4l2_ctrl_s_ctrl);

int __v4l2_ctrl_s_ctrl_int64(struct v4l2_ctrl *ctrl, s64 val)
{
        lockdep_assert_held(ctrl->handler->lock);

        /* It's a driver bug if this happens. */
        if (WARN_ON(ctrl->is_ptr || ctrl->type != V4L2_CTRL_TYPE_INTEGER64))
                return -EINVAL;
        *ctrl->p_new.p_s64 = val;
        return set_ctrl(NULL, ctrl, 0);
}
EXPORT_SYMBOL(__v4l2_ctrl_s_ctrl_int64);

int __v4l2_ctrl_s_ctrl_string(struct v4l2_ctrl *ctrl, const char *s)
{
        lockdep_assert_held(ctrl->handler->lock);

        /* It's a driver bug if this happens. */
        if (WARN_ON(ctrl->type != V4L2_CTRL_TYPE_STRING))
                return -EINVAL;
        strscpy(ctrl->p_new.p_char, s, ctrl->maximum + 1);
        return set_ctrl(NULL, ctrl, 0);
}
EXPORT_SYMBOL(__v4l2_ctrl_s_ctrl_string);

int __v4l2_ctrl_s_ctrl_compound(struct v4l2_ctrl *ctrl,
                                enum v4l2_ctrl_type type, const void *p)
{
        lockdep_assert_held(ctrl->handler->lock);

        /* It's a driver bug if this happens. */
        if (WARN_ON(ctrl->type != type))
                return -EINVAL;
        memcpy(ctrl->p_new.p, p, ctrl->elems * ctrl->elem_size);
        return set_ctrl(NULL, ctrl, 0);
}
EXPORT_SYMBOL(__v4l2_ctrl_s_ctrl_compound);

/*
 * Modify the range of a control.
 */
int __v4l2_ctrl_modify_range(struct v4l2_ctrl *ctrl,
                             s64 min, s64 max, u64 step, s64 def)
{
        bool value_changed;
        bool range_changed = false;
        int ret;

        lockdep_assert_held(ctrl->handler->lock);

        switch (ctrl->type) {
        case V4L2_CTRL_TYPE_INTEGER:
        case V4L2_CTRL_TYPE_INTEGER64:
        case V4L2_CTRL_TYPE_BOOLEAN:
        case V4L2_CTRL_TYPE_MENU:
        case V4L2_CTRL_TYPE_INTEGER_MENU:
        case V4L2_CTRL_TYPE_BITMASK:
        case V4L2_CTRL_TYPE_U8:
        case V4L2_CTRL_TYPE_U16:
        case V4L2_CTRL_TYPE_U32:
                if (ctrl->is_array)
                        return -EINVAL;
                ret = check_range(ctrl->type, min, max, step, def);
                if (ret)
                        return ret;
                break;
        default:
                return -EINVAL;
        }
        if (ctrl->minimum != min || ctrl->maximum != max ||
            ctrl->step != step || ctrl->default_value != def) {
                range_changed = true;
                ctrl->minimum = min;
                ctrl->maximum = max;
                ctrl->step = step;
                ctrl->default_value = def;
        }
        cur_to_new(ctrl);
        if (validate_new(ctrl, ctrl->p_new)) {
                if (ctrl->type == V4L2_CTRL_TYPE_INTEGER64)
                        *ctrl->p_new.p_s64 = def;
                else
                        *ctrl->p_new.p_s32 = def;
        }

        if (ctrl->type == V4L2_CTRL_TYPE_INTEGER64)
                value_changed = *ctrl->p_new.p_s64 != *ctrl->p_cur.p_s64;
        else
                value_changed = *ctrl->p_new.p_s32 != *ctrl->p_cur.p_s32;
        if (value_changed)
                ret = set_ctrl(NULL, ctrl, V4L2_EVENT_CTRL_CH_RANGE);
        else if (range_changed)
                send_event(NULL, ctrl, V4L2_EVENT_CTRL_CH_RANGE);
        return ret;
}
EXPORT_SYMBOL(__v4l2_ctrl_modify_range);

/* Implement VIDIOC_QUERY_EXT_CTRL */
int v4l2_query_ext_ctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_query_ext_ctrl *qc)
{
        const unsigned int next_flags = V4L2_CTRL_FLAG_NEXT_CTRL | V4L2_CTRL_FLAG_NEXT_COMPOUND;
        u32 id = qc->id & V4L2_CTRL_ID_MASK;
        struct v4l2_ctrl_ref *ref;
        struct v4l2_ctrl *ctrl;

        if (!hdl)
                return -EINVAL;

        mutex_lock(hdl->lock);

        /* Try to find it */
        ref = find_ref(hdl, id);

        if ((qc->id & next_flags) && !list_empty(&hdl->ctrl_refs)) {
                bool is_compound;
                /* Match any control that is not hidden */
                unsigned int mask = 1;
                bool match = false;

                if ((qc->id & next_flags) == V4L2_CTRL_FLAG_NEXT_COMPOUND) {
                        /* Match any hidden control */
                        match = true;
                } else if ((qc->id & next_flags) == next_flags) {
                        /* Match any control, compound or not */
                        mask = 0;
                }

                /* Find the next control with ID > qc->id */

                /* Did we reach the end of the control list? */
                if (id >= node2id(hdl->ctrl_refs.prev)) {
                        ref = NULL; /* Yes, so there is no next control */
                } else if (ref) {
                        /*
                         * We found a control with the given ID, so just get
                         * the next valid one in the list.
                         */
                        list_for_each_entry_continue(ref, &hdl->ctrl_refs, node) {
                                is_compound = ref->ctrl->is_array ||
                                        ref->ctrl->type >= V4L2_CTRL_COMPOUND_TYPES;
                                if (id < ref->ctrl->id &&
                                    (is_compound & mask) == match)
                                        break;
                        }
                        if (&ref->node == &hdl->ctrl_refs)
                                ref = NULL;
                } else {
                        /*
                         * No control with the given ID exists, so start
                         * searching for the next largest ID. We know there
                         * is one, otherwise the first 'if' above would have
                         * been true.
                         */
                        list_for_each_entry(ref, &hdl->ctrl_refs, node) {
                                is_compound = ref->ctrl->is_array ||
                                        ref->ctrl->type >= V4L2_CTRL_COMPOUND_TYPES;
                                if (id < ref->ctrl->id &&
                                    (is_compound & mask) == match)
                                        break;

                        }
                        if (&ref->node == &hdl->ctrl_refs)
                                ref = NULL;
                }
        }
        mutex_unlock(hdl->lock);

        if (!ref)
                return -EINVAL;

        ctrl = ref->ctrl;
        memset(qc, 0, sizeof(*qc));
        if (id >= V4L2_CID_PRIVATE_BASE)
                qc->id = id;
        else
                qc->id = ctrl->id;
        strscpy(qc->name, ctrl->name, sizeof(qc->name));
        qc->flags = user_flags(ctrl);
        qc->type = ctrl->type;
        qc->elem_size = ctrl->elem_size;
        qc->elems = ctrl->elems;
        qc->nr_of_dims = ctrl->nr_of_dims;
        memcpy(qc->dims, ctrl->dims, qc->nr_of_dims * sizeof(qc->dims[0]));
        qc->minimum = ctrl->minimum;
        qc->maximum = ctrl->maximum;
        qc->default_value = ctrl->default_value;
        if (ctrl->type == V4L2_CTRL_TYPE_MENU ||
            ctrl->type == V4L2_CTRL_TYPE_INTEGER_MENU)
                qc->step = 1;
        else
                qc->step = ctrl->step;
        return 0;
}
EXPORT_SYMBOL(v4l2_query_ext_ctrl);

/* Implement VIDIOC_QUERYCTRL */
int v4l2_queryctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_queryctrl *qc)
{
        struct v4l2_query_ext_ctrl qec = { qc->id };
        int rc;

        rc = v4l2_query_ext_ctrl(hdl, &qec);
        if (rc)
                return rc;

        qc->id = qec.id;
        qc->type = qec.type;
        qc->flags = qec.flags;
        strscpy(qc->name, qec.name, sizeof(qc->name));
        switch (qc->type) {
        case V4L2_CTRL_TYPE_INTEGER:
        case V4L2_CTRL_TYPE_BOOLEAN:
        case V4L2_CTRL_TYPE_MENU:
        case V4L2_CTRL_TYPE_INTEGER_MENU:
        case V4L2_CTRL_TYPE_STRING:
        case V4L2_CTRL_TYPE_BITMASK:
                qc->minimum = qec.minimum;
                qc->maximum = qec.maximum;
                qc->step = qec.step;
                qc->default_value = qec.default_value;
                break;
        default:
                qc->minimum = 0;
                qc->maximum = 0;
                qc->step = 0;
                qc->default_value = 0;
                break;
        }
        return 0;
}
EXPORT_SYMBOL(v4l2_queryctrl);

/* Implement VIDIOC_QUERYMENU */
int v4l2_querymenu(struct v4l2_ctrl_handler *hdl, struct v4l2_querymenu *qm)
{
        struct v4l2_ctrl *ctrl;
        u32 i = qm->index;

        ctrl = v4l2_ctrl_find(hdl, qm->id);
        if (!ctrl)
                return -EINVAL;

        qm->reserved = 0;
        /* Sanity checks */
        switch (ctrl->type) {
        case V4L2_CTRL_TYPE_MENU:
                if (!ctrl->qmenu)
                        return -EINVAL;
                break;
        case V4L2_CTRL_TYPE_INTEGER_MENU:
                if (!ctrl->qmenu_int)
                        return -EINVAL;
                break;
        default:
                return -EINVAL;
        }

        if (i < ctrl->minimum || i > ctrl->maximum)
                return -EINVAL;

        /* Use mask to see if this menu item should be skipped */
        if (ctrl->menu_skip_mask & (1ULL << i))
                return -EINVAL;
        /* Empty menu items should also be skipped */
        if (ctrl->type == V4L2_CTRL_TYPE_MENU) {
                if (!ctrl->qmenu[i] || ctrl->qmenu[i][0] == '\0')
                        return -EINVAL;
                strscpy(qm->name, ctrl->qmenu[i], sizeof(qm->name));
        } else {
                qm->value = ctrl->qmenu_int[i];
        }
        return 0;
}
EXPORT_SYMBOL(v4l2_querymenu);

/*
 * VIDIOC_LOG_STATUS helpers
 */

int v4l2_ctrl_log_status(struct file *file, void *fh)
{
        struct video_device *vfd = video_devdata(file);
        struct v4l2_fh *vfh = file->private_data;

        if (test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags) && vfd->v4l2_dev)
                v4l2_ctrl_handler_log_status(vfh->ctrl_handler,
                                             vfd->v4l2_dev->name);
        return 0;
}
EXPORT_SYMBOL(v4l2_ctrl_log_status);

int v4l2_ctrl_subdev_log_status(struct v4l2_subdev *sd)
{
        v4l2_ctrl_handler_log_status(sd->ctrl_handler, sd->name);
        return 0;
}
EXPORT_SYMBOL(v4l2_ctrl_subdev_log_status);

/*
 * VIDIOC_(UN)SUBSCRIBE_EVENT implementation
 */

static int v4l2_ctrl_add_event(struct v4l2_subscribed_event *sev,
                               unsigned int elems)
{
        struct v4l2_ctrl *ctrl = v4l2_ctrl_find(sev->fh->ctrl_handler, sev->id);

        if (!ctrl)
                return -EINVAL;

        v4l2_ctrl_lock(ctrl);
        list_add_tail(&sev->node, &ctrl->ev_subs);
        if (ctrl->type != V4L2_CTRL_TYPE_CTRL_CLASS &&
            (sev->flags & V4L2_EVENT_SUB_FL_SEND_INITIAL))
                send_initial_event(sev->fh, ctrl);
        v4l2_ctrl_unlock(ctrl);
        return 0;
}

static void v4l2_ctrl_del_event(struct v4l2_subscribed_event *sev)
{
        struct v4l2_ctrl *ctrl = v4l2_ctrl_find(sev->fh->ctrl_handler, sev->id);

        if (!ctrl)
                return;

        v4l2_ctrl_lock(ctrl);
        list_del(&sev->node);
        v4l2_ctrl_unlock(ctrl);
}

void v4l2_ctrl_replace(struct v4l2_event *old, const struct v4l2_event *new)
{
        u32 old_changes = old->u.ctrl.changes;

        old->u.ctrl = new->u.ctrl;
        old->u.ctrl.changes |= old_changes;
}
EXPORT_SYMBOL(v4l2_ctrl_replace);

void v4l2_ctrl_merge(const struct v4l2_event *old, struct v4l2_event *new)
{
        new->u.ctrl.changes |= old->u.ctrl.changes;
}
EXPORT_SYMBOL(v4l2_ctrl_merge);

const struct v4l2_subscribed_event_ops v4l2_ctrl_sub_ev_ops = {
        .add = v4l2_ctrl_add_event,
        .del = v4l2_ctrl_del_event,
        .replace = v4l2_ctrl_replace,
        .merge = v4l2_ctrl_merge,
};
EXPORT_SYMBOL(v4l2_ctrl_sub_ev_ops);

int v4l2_ctrl_subscribe_event(struct v4l2_fh *fh,
                              const struct v4l2_event_subscription *sub)
{
        if (sub->type == V4L2_EVENT_CTRL)
                return v4l2_event_subscribe(fh, sub, 0, &v4l2_ctrl_sub_ev_ops);
        return -EINVAL;
}
EXPORT_SYMBOL(v4l2_ctrl_subscribe_event);

int v4l2_ctrl_subdev_subscribe_event(struct v4l2_subdev *sd, struct v4l2_fh *fh,
                                     struct v4l2_event_subscription *sub)
{
        if (!sd->ctrl_handler)
                return -EINVAL;
        return v4l2_ctrl_subscribe_event(fh, sub);
}
EXPORT_SYMBOL(v4l2_ctrl_subdev_subscribe_event);

/*
 * poll helper
 */
__poll_t v4l2_ctrl_poll(struct file *file, struct poll_table_struct *wait)
{
        struct v4l2_fh *fh = file->private_data;

        poll_wait(file, &fh->wait, wait);
        if (v4l2_event_pending(fh))
                return EPOLLPRI;
        return 0;
}
EXPORT_SYMBOL(v4l2_ctrl_poll);