// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * V4L2 controls framework Request API implementation.
 *
 * Copyright (C) 2018-2021  Hans Verkuil <hverkuil-cisco@xs4all.nl>
 */

#define pr_fmt(fmt) "v4l2-ctrls: " fmt

#include <linux/export.h>
#include <linux/slab.h>
#include <media/v4l2-ctrls.h>
#include <media/v4l2-dev.h>
#include <media/v4l2-ioctl.h>

#include "v4l2-ctrls-priv.h"

/* Initialize the request-related fields in a control handler */
void v4l2_ctrl_handler_init_request(struct v4l2_ctrl_handler *hdl)
{
        INIT_LIST_HEAD(&hdl->requests);
        INIT_LIST_HEAD(&hdl->requests_queued);
        hdl->request_is_queued = false;
        media_request_object_init(&hdl->req_obj);
}

/* Free the request-related fields in a control handler */
void v4l2_ctrl_handler_free_request(struct v4l2_ctrl_handler *hdl)
{
        struct v4l2_ctrl_handler *req, *next_req;

        /*
         * Do nothing if this isn't the main handler or the main
         * handler is not used in any request.
         *
         * The main handler can be identified by having a NULL ops pointer in
         * the request object.
         */
        if (hdl->req_obj.ops || list_empty(&hdl->requests))
                return;

        /*
         * If the main handler is freed and it is used by handler objects in
         * outstanding requests, then unbind and put those objects before
         * freeing the main handler.
         */
        list_for_each_entry_safe(req, next_req, &hdl->requests, requests) {
                media_request_object_unbind(&req->req_obj);
                media_request_object_put(&req->req_obj);
        }
}

static int v4l2_ctrl_request_clone(struct v4l2_ctrl_handler *hdl,
                                   const struct v4l2_ctrl_handler *from)
{
        struct v4l2_ctrl_ref *ref;
        int err = 0;

        if (WARN_ON(!hdl || hdl == from))
                return -EINVAL;

        if (hdl->error)
                return hdl->error;

        WARN_ON(hdl->lock != &hdl->_lock);

        mutex_lock(from->lock);
        list_for_each_entry(ref, &from->ctrl_refs, node) {
                struct v4l2_ctrl *ctrl = ref->ctrl;
                struct v4l2_ctrl_ref *new_ref;

                /* Skip refs inherited from other devices */
                if (ref->from_other_dev)
                        continue;
                err = handler_new_ref(hdl, ctrl, &new_ref, false, true);
                if (err)
                        break;
        }
        mutex_unlock(from->lock);
        return err;
}

static void v4l2_ctrl_request_queue(struct media_request_object *obj)
{
        struct v4l2_ctrl_handler *hdl =
                container_of(obj, struct v4l2_ctrl_handler, req_obj);
        struct v4l2_ctrl_handler *main_hdl = obj->priv;

        mutex_lock(main_hdl->lock);
        list_add_tail(&hdl->requests_queued, &main_hdl->requests_queued);
        hdl->request_is_queued = true;
        mutex_unlock(main_hdl->lock);
}

static void v4l2_ctrl_request_unbind(struct media_request_object *obj)
{
        struct v4l2_ctrl_handler *hdl =
                container_of(obj, struct v4l2_ctrl_handler, req_obj);
        struct v4l2_ctrl_handler *main_hdl = obj->priv;

        mutex_lock(main_hdl->lock);
        list_del_init(&hdl->requests);
        if (hdl->request_is_queued) {
                list_del_init(&hdl->requests_queued);
                hdl->request_is_queued = false;
        }
        mutex_unlock(main_hdl->lock);
}

static void v4l2_ctrl_request_release(struct media_request_object *obj)
{
        struct v4l2_ctrl_handler *hdl =
                container_of(obj, struct v4l2_ctrl_handler, req_obj);

        v4l2_ctrl_handler_free(hdl);
        kfree(hdl);
}

static const struct media_request_object_ops req_ops = {
        .queue = v4l2_ctrl_request_queue,
        .unbind = v4l2_ctrl_request_unbind,
        .release = v4l2_ctrl_request_release,
};

struct v4l2_ctrl_handler *v4l2_ctrl_request_hdl_find(struct media_request *req,
                                                     struct v4l2_ctrl_handler *parent)
{
        struct media_request_object *obj;

        if (WARN_ON(req->state != MEDIA_REQUEST_STATE_VALIDATING &&
                    req->state != MEDIA_REQUEST_STATE_QUEUED))
                return NULL;

        obj = media_request_object_find(req, &req_ops, parent);
        if (obj)
                return container_of(obj, struct v4l2_ctrl_handler, req_obj);
        return NULL;
}
EXPORT_SYMBOL_GPL(v4l2_ctrl_request_hdl_find);

struct v4l2_ctrl *
v4l2_ctrl_request_hdl_ctrl_find(struct v4l2_ctrl_handler *hdl, u32 id)
{
        struct v4l2_ctrl_ref *ref = find_ref_lock(hdl, id);

        return (ref && ref->valid_p_req) ? ref->ctrl : NULL;
}
EXPORT_SYMBOL_GPL(v4l2_ctrl_request_hdl_ctrl_find);

static int v4l2_ctrl_request_bind(struct media_request *req,
                                  struct v4l2_ctrl_handler *hdl,
                                  struct v4l2_ctrl_handler *from)
{
        int ret;

        ret = v4l2_ctrl_request_clone(hdl, from);

        if (!ret) {
                ret = media_request_object_bind(req, &req_ops,
                                                from, false, &hdl->req_obj);
                if (!ret) {
                        mutex_lock(from->lock);
                        list_add_tail(&hdl->requests, &from->requests);
                        mutex_unlock(from->lock);
                }
        }
        return ret;
}

static struct media_request_object *
v4l2_ctrls_find_req_obj(struct v4l2_ctrl_handler *hdl,
                        struct media_request *req, bool set)
{
        struct media_request_object *obj;
        struct v4l2_ctrl_handler *new_hdl;
        int ret;

        if (IS_ERR(req))
                return ERR_CAST(req);

        if (set && WARN_ON(req->state != MEDIA_REQUEST_STATE_UPDATING))
                return ERR_PTR(-EBUSY);

        obj = media_request_object_find(req, &req_ops, hdl);
        if (obj)
                return obj;
        /*
         * If there are no controls in this completed request,
         * then that can only happen if:
         *
         * 1) no controls were present in the queued request, and
         * 2) v4l2_ctrl_request_complete() could not allocate a
         *    control handler object to store the completed state in.
         *
         * So return ENOMEM to indicate that there was an out-of-memory
         * error.
         */
        if (!set)
                return ERR_PTR(-ENOMEM);

        new_hdl = kzalloc(sizeof(*new_hdl), GFP_KERNEL);
        if (!new_hdl)
                return ERR_PTR(-ENOMEM);

        obj = &new_hdl->req_obj;
        ret = v4l2_ctrl_handler_init(new_hdl, (hdl->nr_of_buckets - 1) * 8);
        if (!ret)
                ret = v4l2_ctrl_request_bind(req, new_hdl, hdl);
        if (ret) {
                v4l2_ctrl_handler_free(new_hdl);
                kfree(new_hdl);
                return ERR_PTR(ret);
        }

        media_request_object_get(obj);
        return obj;
}

int v4l2_g_ext_ctrls_request(struct v4l2_ctrl_handler *hdl, struct video_device *vdev,
                             struct media_device *mdev, struct v4l2_ext_controls *cs)
{
        struct media_request_object *obj = NULL;
        struct media_request *req = NULL;
        int ret;

        if (!mdev || cs->request_fd < 0)
                return -EINVAL;

        req = media_request_get_by_fd(mdev, cs->request_fd);
        if (IS_ERR(req))
                return PTR_ERR(req);

        if (req->state != MEDIA_REQUEST_STATE_COMPLETE) {
                media_request_put(req);
                return -EACCES;
        }

        ret = media_request_lock_for_access(req);
        if (ret) {
                media_request_put(req);
                return ret;
        }

        obj = v4l2_ctrls_find_req_obj(hdl, req, false);
        if (IS_ERR(obj)) {
                media_request_unlock_for_access(req);
                media_request_put(req);
                return PTR_ERR(obj);
        }

        hdl = container_of(obj, struct v4l2_ctrl_handler,
                           req_obj);
        ret = v4l2_g_ext_ctrls_common(hdl, cs, vdev);

        media_request_unlock_for_access(req);
        media_request_object_put(obj);
        media_request_put(req);
        return ret;
}

int try_set_ext_ctrls_request(struct v4l2_fh *fh,
                              struct v4l2_ctrl_handler *hdl,
                              struct video_device *vdev,
                              struct media_device *mdev,
                              struct v4l2_ext_controls *cs, bool set)
{
        struct media_request_object *obj = NULL;
        struct media_request *req = NULL;
        int ret;

        if (!mdev) {
                dprintk(vdev, "%s: missing media device\n",
                        video_device_node_name(vdev));
                return -EINVAL;
        }

        if (cs->request_fd < 0) {
                dprintk(vdev, "%s: invalid request fd %d\n",
                        video_device_node_name(vdev), cs->request_fd);
                return -EINVAL;
        }

        req = media_request_get_by_fd(mdev, cs->request_fd);
        if (IS_ERR(req)) {
                dprintk(vdev, "%s: cannot find request fd %d\n",
                        video_device_node_name(vdev), cs->request_fd);
                return PTR_ERR(req);
        }

        ret = media_request_lock_for_update(req);
        if (ret) {
                dprintk(vdev, "%s: cannot lock request fd %d\n",
                        video_device_node_name(vdev), cs->request_fd);
                media_request_put(req);
                return ret;
        }

        obj = v4l2_ctrls_find_req_obj(hdl, req, set);
        if (IS_ERR(obj)) {
                dprintk(vdev,
                        "%s: cannot find request object for request fd %d\n",
                        video_device_node_name(vdev),
                        cs->request_fd);
                media_request_unlock_for_update(req);
                media_request_put(req);
                return PTR_ERR(obj);
        }

        hdl = container_of(obj, struct v4l2_ctrl_handler,
                           req_obj);
        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);

        media_request_unlock_for_update(req);
        media_request_object_put(obj);
        media_request_put(req);

        return ret;
}

void v4l2_ctrl_request_complete(struct media_request *req,
                                struct v4l2_ctrl_handler *main_hdl)
{
        struct media_request_object *obj;
        struct v4l2_ctrl_handler *hdl;
        struct v4l2_ctrl_ref *ref;

        if (!req || !main_hdl)
                return;

        /*
         * Note that it is valid if nothing was found. It means
         * that this request doesn't have any controls and so just
         * wants to leave the controls unchanged.
         */
        obj = media_request_object_find(req, &req_ops, main_hdl);
        if (!obj) {
                int ret;

                /* Create a new request so the driver can return controls */
                hdl = kzalloc(sizeof(*hdl), GFP_KERNEL);
                if (!hdl)
                        return;

                ret = v4l2_ctrl_handler_init(hdl, (main_hdl->nr_of_buckets - 1) * 8);
                if (!ret)
                        ret = v4l2_ctrl_request_bind(req, hdl, main_hdl);
                if (ret) {
                        v4l2_ctrl_handler_free(hdl);
                        kfree(hdl);
                        return;
                }
                hdl->request_is_queued = true;
                obj = media_request_object_find(req, &req_ops, main_hdl);
        }
        hdl = container_of(obj, struct v4l2_ctrl_handler, req_obj);

        list_for_each_entry(ref, &hdl->ctrl_refs, node) {
                struct v4l2_ctrl *ctrl = ref->ctrl;
                struct v4l2_ctrl *master = ctrl->cluster[0];
                unsigned int i;

                if (ctrl->flags & V4L2_CTRL_FLAG_VOLATILE) {
                        v4l2_ctrl_lock(master);
                        /* g_volatile_ctrl will update the current control values */
                        for (i = 0; i < master->ncontrols; i++)
                                cur_to_new(master->cluster[i]);
                        call_op(master, g_volatile_ctrl);
                        new_to_req(ref);
                        v4l2_ctrl_unlock(master);
                        continue;
                }
                if (ref->valid_p_req)
                        continue;

                /* Copy the current control value into the request */
                v4l2_ctrl_lock(ctrl);
                cur_to_req(ref);
                v4l2_ctrl_unlock(ctrl);
        }

        mutex_lock(main_hdl->lock);
        WARN_ON(!hdl->request_is_queued);
        list_del_init(&hdl->requests_queued);
        hdl->request_is_queued = false;
        mutex_unlock(main_hdl->lock);
        media_request_object_complete(obj);
        media_request_object_put(obj);
}
EXPORT_SYMBOL(v4l2_ctrl_request_complete);

int v4l2_ctrl_request_setup(struct media_request *req,
                            struct v4l2_ctrl_handler *main_hdl)
{
        struct media_request_object *obj;
        struct v4l2_ctrl_handler *hdl;
        struct v4l2_ctrl_ref *ref;
        int ret = 0;

        if (!req || !main_hdl)
                return 0;

        if (WARN_ON(req->state != MEDIA_REQUEST_STATE_QUEUED))
                return -EBUSY;

        /*
         * Note that it is valid if nothing was found. It means
         * that this request doesn't have any controls and so just
         * wants to leave the controls unchanged.
         */
        obj = media_request_object_find(req, &req_ops, main_hdl);
        if (!obj)
                return 0;
        if (obj->completed) {
                media_request_object_put(obj);
                return -EBUSY;
        }
        hdl = container_of(obj, struct v4l2_ctrl_handler, req_obj);

        list_for_each_entry(ref, &hdl->ctrl_refs, node)
                ref->req_done = false;

        list_for_each_entry(ref, &hdl->ctrl_refs, node) {
                struct v4l2_ctrl *ctrl = ref->ctrl;
                struct v4l2_ctrl *master = ctrl->cluster[0];
                bool have_new_data = false;
                int i;

                /*
                 * Skip if this control was already handled by a cluster.
                 * Skip button controls and read-only controls.
                 */
                if (ref->req_done || (ctrl->flags & V4L2_CTRL_FLAG_READ_ONLY))
                        continue;

                v4l2_ctrl_lock(master);
                for (i = 0; i < master->ncontrols; i++) {
                        if (master->cluster[i]) {
                                struct v4l2_ctrl_ref *r =
                                        find_ref(hdl, master->cluster[i]->id);

                                if (r->valid_p_req) {
                                        have_new_data = true;
                                        break;
                                }
                        }
                }
                if (!have_new_data) {
                        v4l2_ctrl_unlock(master);
                        continue;
                }

                for (i = 0; i < master->ncontrols; i++) {
                        if (master->cluster[i]) {
                                struct v4l2_ctrl_ref *r =
                                        find_ref(hdl, master->cluster[i]->id);

                                req_to_new(r);
                                master->cluster[i]->is_new = 1;
                                r->req_done = true;
                        }
                }
                /*
                 * 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)) {
                        s32 new_auto_val = *master->p_new.p_s32;

                        /*
                         * 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);
                }

                ret = try_or_set_cluster(NULL, master, true, 0);
                v4l2_ctrl_unlock(master);

                if (ret)
                        break;
        }

        media_request_object_put(obj);
        return ret;
}
EXPORT_SYMBOL(v4l2_ctrl_request_setup);