// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
/*
 * Copyright (c) 2014 Raspberry Pi (Trading) Ltd. All rights reserved.
 * Copyright (c) 2010-2012 Broadcom. All rights reserved.
 */

#include <linux/cdev.h>
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/compat.h>
#include <linux/miscdevice.h>

#include <linux/raspberrypi/vchiq_core.h>
#include <linux/raspberrypi/vchiq_arm.h>
#include <linux/raspberrypi/vchiq_debugfs.h>

#include "vchiq_ioctl.h"

static const char *const ioctl_names[] = {
        "CONNECT",
        "SHUTDOWN",
        "CREATE_SERVICE",
        "REMOVE_SERVICE",
        "QUEUE_MESSAGE",
        "QUEUE_BULK_TRANSMIT",
        "QUEUE_BULK_RECEIVE",
        "AWAIT_COMPLETION",
        "DEQUEUE_MESSAGE",
        "GET_CLIENT_ID",
        "GET_CONFIG",
        "CLOSE_SERVICE",
        "USE_SERVICE",
        "RELEASE_SERVICE",
        "SET_SERVICE_OPTION",
        "DUMP_PHYS_MEM",
        "LIB_VERSION",
        "CLOSE_DELIVERED"
};

static_assert(ARRAY_SIZE(ioctl_names) == (VCHIQ_IOC_MAX + 1));

static void
user_service_free(void *userdata)
{
        kfree(userdata);
}

static void close_delivered(struct user_service *user_service)
{
        dev_dbg(user_service->service->state->dev,
                "arm: (handle=%x)\n", user_service->service->handle);

        if (user_service->close_pending) {
                /* Allow the underlying service to be culled */
                vchiq_service_put(user_service->service);

                /* Wake the user-thread blocked in close_ or remove_service */
                complete(&user_service->close_event);

                user_service->close_pending = 0;
        }
}

struct vchiq_io_copy_callback_context {
        struct vchiq_element *element;
        size_t element_offset;
        unsigned long elements_to_go;
};

static ssize_t vchiq_ioc_copy_element_data(void *context, void *dest,
                                           size_t offset, size_t maxsize)
{
        struct vchiq_io_copy_callback_context *cc = context;
        size_t total_bytes_copied = 0;
        size_t bytes_this_round;

        while (total_bytes_copied < maxsize) {
                if (!cc->elements_to_go)
                        return total_bytes_copied;

                if (!cc->element->size) {
                        cc->elements_to_go--;
                        cc->element++;
                        cc->element_offset = 0;
                        continue;
                }

                bytes_this_round = min(cc->element->size - cc->element_offset,
                                       maxsize - total_bytes_copied);

                if (copy_from_user(dest + total_bytes_copied,
                                   cc->element->data + cc->element_offset,
                                   bytes_this_round))
                        return -EFAULT;

                cc->element_offset += bytes_this_round;
                total_bytes_copied += bytes_this_round;

                if (cc->element_offset == cc->element->size) {
                        cc->elements_to_go--;
                        cc->element++;
                        cc->element_offset = 0;
                }
        }

        return maxsize;
}

static int
vchiq_ioc_queue_message(struct vchiq_instance *instance, unsigned int handle,
                        struct vchiq_element *elements, unsigned long count)
{
        struct vchiq_io_copy_callback_context context;
        int status = 0;
        unsigned long i;
        size_t total_size = 0;

        context.element = elements;
        context.element_offset = 0;
        context.elements_to_go = count;

        for (i = 0; i < count; i++) {
                if (!elements[i].data && elements[i].size != 0)
                        return -EFAULT;

                total_size += elements[i].size;
        }

        status = vchiq_queue_message(instance, handle, vchiq_ioc_copy_element_data,
                                     &context, total_size);

        if (status == -EINVAL)
                return -EIO;
        else if (status == -EAGAIN)
                return -EINTR;
        return 0;
}

static int vchiq_ioc_create_service(struct vchiq_instance *instance,
                                    struct vchiq_create_service *args)
{
        struct user_service *user_service = NULL;
        struct vchiq_service *service;
        int status = 0;
        struct vchiq_service_params_kernel params;
        int srvstate;

        if (args->is_open && !instance->connected)
                return -ENOTCONN;

        user_service = kmalloc_obj(*user_service);
        if (!user_service)
                return -ENOMEM;

        if (args->is_open) {
                srvstate = VCHIQ_SRVSTATE_OPENING;
        } else {
                srvstate = instance->connected ?
                         VCHIQ_SRVSTATE_LISTENING : VCHIQ_SRVSTATE_HIDDEN;
        }

        params = (struct vchiq_service_params_kernel) {
                .fourcc   = args->params.fourcc,
                .callback = service_callback,
                .userdata = user_service,
                .version  = args->params.version,
                .version_min = args->params.version_min,
        };
        service = vchiq_add_service_internal(instance->state, &params,
                                             srvstate, instance,
                                             user_service_free);
        if (!service) {
                kfree(user_service);
                return -EEXIST;
        }

        user_service->service = service;
        user_service->userdata = args->params.userdata;
        user_service->instance = instance;
        user_service->is_vchi = (args->is_vchi != 0);
        user_service->dequeue_pending = 0;
        user_service->close_pending = 0;
        user_service->message_available_pos = instance->completion_remove - 1;
        user_service->msg_insert = 0;
        user_service->msg_remove = 0;
        init_completion(&user_service->insert_event);
        init_completion(&user_service->remove_event);
        init_completion(&user_service->close_event);

        if (args->is_open) {
                status = vchiq_open_service_internal(service, instance->pid);
                if (status) {
                        vchiq_remove_service(instance, service->handle);
                        return (status == -EAGAIN) ?
                                -EINTR : -EIO;
                }
        }
        args->handle = service->handle;

        return 0;
}

static int vchiq_ioc_dequeue_message(struct vchiq_instance *instance,
                                     struct vchiq_dequeue_message *args)
{
        struct user_service *user_service;
        struct vchiq_service *service;
        struct vchiq_header *header;
        int ret;

        DEBUG_INITIALISE(instance->state->local);
        DEBUG_TRACE(DEQUEUE_MESSAGE_LINE);
        service = find_service_for_instance(instance, args->handle);
        if (!service)
                return -EINVAL;

        user_service = (struct user_service *)service->base.userdata;
        if (user_service->is_vchi == 0) {
                ret = -EINVAL;
                goto out;
        }

        spin_lock(&service->state->msg_queue_spinlock);
        if (user_service->msg_remove == user_service->msg_insert) {
                if (!args->blocking) {
                        spin_unlock(&service->state->msg_queue_spinlock);
                        DEBUG_TRACE(DEQUEUE_MESSAGE_LINE);
                        ret = -EWOULDBLOCK;
                        goto out;
                }
                user_service->dequeue_pending = 1;
                ret = 0;
                do {
                        spin_unlock(&service->state->msg_queue_spinlock);
                        DEBUG_TRACE(DEQUEUE_MESSAGE_LINE);
                        if (wait_for_completion_interruptible(&user_service->insert_event)) {
                                dev_dbg(service->state->dev, "arm: DEQUEUE_MESSAGE interrupted\n");
                                ret = -EINTR;
                                break;
                        }
                        spin_lock(&service->state->msg_queue_spinlock);
                } while (user_service->msg_remove == user_service->msg_insert);

                if (ret)
                        goto out;
        }

        if (WARN_ON_ONCE((int)(user_service->msg_insert -
                         user_service->msg_remove) < 0)) {
                spin_unlock(&service->state->msg_queue_spinlock);
                ret = -EINVAL;
                goto out;
        }

        header = user_service->msg_queue[user_service->msg_remove &
                (MSG_QUEUE_SIZE - 1)];
        user_service->msg_remove++;
        spin_unlock(&service->state->msg_queue_spinlock);

        complete(&user_service->remove_event);
        if (!header) {
                ret = -ENOTCONN;
        } else if (header->size <= args->bufsize) {
                /* Copy to user space if msgbuf is not NULL */
                if (!args->buf || (copy_to_user(args->buf, header->data, header->size) == 0)) {
                        ret = header->size;
                        vchiq_release_message(instance, service->handle, header);
                } else {
                        ret = -EFAULT;
                }
        } else {
                dev_err(service->state->dev,
                        "arm: header %p: bufsize %x < size %x\n",
                        header, args->bufsize, header->size);
                WARN(1, "invalid size\n");
                ret = -EMSGSIZE;
        }
        DEBUG_TRACE(DEQUEUE_MESSAGE_LINE);
out:
        vchiq_service_put(service);
        return ret;
}

static int vchiq_irq_queue_bulk_tx_rx(struct vchiq_instance *instance,
                                      struct vchiq_queue_bulk_transfer *args,
                                      enum vchiq_bulk_dir dir,
                                      enum vchiq_bulk_mode __user *mode)
{
        struct vchiq_service *service;
        struct bulk_waiter_node *waiter = NULL, *iter;
        struct vchiq_bulk bulk_params = {};
        int status = 0;
        int ret;

        service = find_service_for_instance(instance, args->handle);
        if (!service)
                return -EINVAL;

        if (args->mode == VCHIQ_BULK_MODE_BLOCKING) {
                waiter = kzalloc_obj(*waiter);
                if (!waiter) {
                        ret = -ENOMEM;
                        goto out;
                }

                bulk_params.uoffset = args->data;
                bulk_params.mode = args->mode;
                bulk_params.size = args->size;
                bulk_params.dir = dir;
                bulk_params.waiter = &waiter->bulk_waiter;

                status = vchiq_bulk_xfer_blocking(instance, args->handle,
                                                  &bulk_params);
        } else if (args->mode == VCHIQ_BULK_MODE_WAITING) {
                mutex_lock(&instance->bulk_waiter_list_mutex);
                list_for_each_entry(iter, &instance->bulk_waiter_list,
                                    list) {
                        if (iter->pid == current->pid) {
                                list_del(&iter->list);
                                waiter = iter;
                                break;
                        }
                }
                mutex_unlock(&instance->bulk_waiter_list_mutex);
                if (!waiter) {
                        dev_err(service->state->dev,
                                "arm: no bulk_waiter found for pid %d\n", current->pid);
                        ret = -ESRCH;
                        goto out;
                }
                dev_dbg(service->state->dev, "arm: found bulk_waiter %p for pid %d\n",
                        waiter, current->pid);

                status = vchiq_bulk_xfer_waiting(instance, args->handle,
                                                 &waiter->bulk_waiter);
        } else {
                bulk_params.uoffset = args->data;
                bulk_params.mode = args->mode;
                bulk_params.size = args->size;
                bulk_params.dir = dir;
                bulk_params.cb_userdata = args->userdata;

                status = vchiq_bulk_xfer_callback(instance, args->handle,
                                                  &bulk_params);
        }

        if (!waiter) {
                ret = 0;
                goto out;
        }

        if ((status != -EAGAIN) || fatal_signal_pending(current) ||
            !waiter->bulk_waiter.bulk) {
                if (waiter->bulk_waiter.bulk) {
                        /* Cancel the signal when the transfer completes. */
                        spin_lock(&service->state->bulk_waiter_spinlock);
                        waiter->bulk_waiter.bulk->waiter = NULL;
                        spin_unlock(&service->state->bulk_waiter_spinlock);
                }
                kfree(waiter);
                ret = 0;
        } else {
                const enum vchiq_bulk_mode mode_waiting =
                        VCHIQ_BULK_MODE_WAITING;
                waiter->pid = current->pid;
                mutex_lock(&instance->bulk_waiter_list_mutex);
                list_add(&waiter->list, &instance->bulk_waiter_list);
                mutex_unlock(&instance->bulk_waiter_list_mutex);
                dev_dbg(service->state->dev, "arm: saved bulk_waiter %p for pid %d\n",
                        waiter, current->pid);

                ret = put_user(mode_waiting, mode);
        }
out:
        vchiq_service_put(service);
        if (ret)
                return ret;
        else if (status == -EINVAL)
                return -EIO;
        else if (status == -EAGAIN)
                return -EINTR;
        return 0;
}

/* read a user pointer value from an array pointers in user space */
static inline int vchiq_get_user_ptr(void __user **buf, void __user *ubuf, int index)
{
        int ret;

        if (in_compat_syscall()) {
                compat_uptr_t ptr32;
                compat_uptr_t __user *uptr = ubuf;

                ret = get_user(ptr32, uptr + index);
                if (ret)
                        return ret;

                *buf = compat_ptr(ptr32);
        } else {
                uintptr_t ptr, __user *uptr = ubuf;

                ret = get_user(ptr, uptr + index);

                if (ret)
                        return ret;

                *buf = (void __user *)ptr;
        }

        return 0;
}

struct vchiq_completion_data32 {
        enum vchiq_reason reason;
        compat_uptr_t header;
        compat_uptr_t service_userdata;
        compat_uptr_t cb_data;
};

static int vchiq_put_completion(struct vchiq_completion_data __user *buf,
                                struct vchiq_completion_data *completion,
                                int index)
{
        struct vchiq_completion_data32 __user *buf32 = (void __user *)buf;

        if (in_compat_syscall()) {
                struct vchiq_completion_data32 tmp = {
                        .reason           = completion->reason,
                        .header           = ptr_to_compat(completion->header),
                        .service_userdata = ptr_to_compat(completion->service_userdata),
                        .cb_data          = ptr_to_compat(completion->cb_userdata),
                };
                if (copy_to_user(&buf32[index], &tmp, sizeof(tmp)))
                        return -EFAULT;
        } else {
                if (copy_to_user(&buf[index], completion, sizeof(*completion)))
                        return -EFAULT;
        }

        return 0;
}

static int vchiq_ioc_await_completion(struct vchiq_instance *instance,
                                      struct vchiq_await_completion *args,
                                      int __user *msgbufcountp)
{
        int msgbufcount;
        int remove;
        int ret;

        DEBUG_INITIALISE(instance->state->local);

        DEBUG_TRACE(AWAIT_COMPLETION_LINE);
        if (!instance->connected)
                return -ENOTCONN;

        mutex_lock(&instance->completion_mutex);

        DEBUG_TRACE(AWAIT_COMPLETION_LINE);
        while ((instance->completion_remove == instance->completion_insert) && !instance->closing) {
                int rc;

                DEBUG_TRACE(AWAIT_COMPLETION_LINE);
                mutex_unlock(&instance->completion_mutex);
                rc = wait_for_completion_interruptible(&instance->insert_event);
                mutex_lock(&instance->completion_mutex);
                if (rc) {
                        DEBUG_TRACE(AWAIT_COMPLETION_LINE);
                        dev_dbg(instance->state->dev, "arm: AWAIT_COMPLETION interrupted\n");
                        ret = -EINTR;
                        goto out;
                }
        }
        DEBUG_TRACE(AWAIT_COMPLETION_LINE);

        msgbufcount = args->msgbufcount;
        remove = instance->completion_remove;

        for (ret = 0; ret < args->count; ret++) {
                struct vchiq_completion_data_kernel *completion;
                struct vchiq_completion_data user_completion;
                struct vchiq_service *service;
                struct user_service *user_service;
                struct vchiq_header *header;

                if (remove == instance->completion_insert)
                        break;

                completion = &instance->completions[remove & (MAX_COMPLETIONS - 1)];

                /*
                 * A read memory barrier is needed to stop
                 * prefetch of a stale completion record
                 */
                rmb();

                service = completion->service_userdata;
                user_service = service->base.userdata;

                memset(&user_completion, 0, sizeof(user_completion));
                user_completion = (struct vchiq_completion_data) {
                        .reason = completion->reason,
                        .service_userdata = user_service->userdata,
                };

                header = completion->header;
                if (header) {
                        void __user *msgbuf;
                        int msglen;

                        msglen = header->size + sizeof(struct vchiq_header);
                        /* This must be a VCHIQ-style service */
                        if (args->msgbufsize < msglen) {
                                dev_err(service->state->dev,
                                        "arm: header %p: msgbufsize %x < msglen %x\n",
                                        header, args->msgbufsize, msglen);
                                WARN(1, "invalid message size\n");
                                if (ret == 0)
                                        ret = -EMSGSIZE;
                                break;
                        }
                        if (msgbufcount <= 0)
                                /* Stall here for lack of a buffer for the message. */
                                break;
                        /* Get the pointer from user space */
                        msgbufcount--;
                        if (vchiq_get_user_ptr(&msgbuf, args->msgbufs,
                                               msgbufcount)) {
                                if (ret == 0)
                                        ret = -EFAULT;
                                break;
                        }

                        /* Copy the message to user space */
                        if (copy_to_user(msgbuf, header, msglen)) {
                                if (ret == 0)
                                        ret = -EFAULT;
                                break;
                        }

                        /* Now it has been copied, the message can be released. */
                        vchiq_release_message(instance, service->handle, header);

                        /* The completion must point to the msgbuf. */
                        user_completion.header = msgbuf;
                }

                if ((completion->reason == VCHIQ_SERVICE_CLOSED) &&
                    !instance->use_close_delivered)
                        vchiq_service_put(service);

                user_completion.cb_userdata = completion->cb_userdata;

                if (vchiq_put_completion(args->buf, &user_completion, ret)) {
                        if (ret == 0)
                                ret = -EFAULT;
                        break;
                }

                /*
                 * Ensure that the above copy has completed
                 * before advancing the remove pointer.
                 */
                mb();
                remove++;
                instance->completion_remove = remove;
        }

        if (msgbufcount != args->msgbufcount) {
                if (put_user(msgbufcount, msgbufcountp))
                        ret = -EFAULT;
        }
out:
        if (ret)
                complete(&instance->remove_event);
        mutex_unlock(&instance->completion_mutex);
        DEBUG_TRACE(AWAIT_COMPLETION_LINE);

        return ret;
}

static long
vchiq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
        struct vchiq_instance *instance = file->private_data;
        int status = 0;
        struct vchiq_service *service = NULL;
        long ret = 0;
        int i, rc;

        dev_dbg(instance->state->dev, "arm: instance %p, cmd %s, arg %lx\n", instance,
                ((_IOC_TYPE(cmd) == VCHIQ_IOC_MAGIC) && (_IOC_NR(cmd) <= VCHIQ_IOC_MAX)) ?
                ioctl_names[_IOC_NR(cmd)] : "<invalid>", arg);

        switch (cmd) {
        case VCHIQ_IOC_SHUTDOWN:
                if (!instance->connected)
                        break;

                /* Remove all services */
                i = 0;
                while ((service = next_service_by_instance(instance->state,
                                                           instance, &i))) {
                        status = vchiq_remove_service(instance, service->handle);
                        vchiq_service_put(service);
                        if (status)
                                break;
                }
                service = NULL;

                if (!status) {
                        /* Wake the completion thread and ask it to exit */
                        instance->closing = 1;
                        complete(&instance->insert_event);
                }

                break;

        case VCHIQ_IOC_CONNECT:
                if (instance->connected) {
                        ret = -EINVAL;
                        break;
                }
                rc = mutex_lock_killable(&instance->state->mutex);
                if (rc) {
                        dev_err(instance->state->dev,
                                "arm: vchiq: connect: could not lock mutex for state %d: %d\n",
                                instance->state->id, rc);
                        ret = -EINTR;
                        break;
                }
                status = vchiq_connect_internal(instance->state, instance);
                mutex_unlock(&instance->state->mutex);

                if (!status)
                        instance->connected = 1;
                else
                        dev_err(instance->state->dev,
                                "arm: vchiq: could not connect: %d\n", status);
                break;

        case VCHIQ_IOC_CREATE_SERVICE: {
                struct vchiq_create_service __user *argp;
                struct vchiq_create_service args;

                argp = (void __user *)arg;
                if (copy_from_user(&args, argp, sizeof(args))) {
                        ret = -EFAULT;
                        break;
                }

                ret = vchiq_ioc_create_service(instance, &args);
                if (ret < 0)
                        break;

                if (put_user(args.handle, &argp->handle)) {
                        vchiq_remove_service(instance, args.handle);
                        ret = -EFAULT;
                }
        } break;

        case VCHIQ_IOC_CLOSE_SERVICE:
        case VCHIQ_IOC_REMOVE_SERVICE: {
                unsigned int handle = (unsigned int)arg;
                struct user_service *user_service;

                service = find_service_for_instance(instance, handle);
                if (!service) {
                        ret = -EINVAL;
                        break;
                }

                user_service = service->base.userdata;

                /*
                 * close_pending is false on first entry, and when the
                 * wait in vchiq_close_service has been interrupted.
                 */
                if (!user_service->close_pending) {
                        status = (cmd == VCHIQ_IOC_CLOSE_SERVICE) ?
                                 vchiq_close_service(instance, service->handle) :
                                 vchiq_remove_service(instance, service->handle);
                        if (status)
                                break;
                }

                /*
                 * close_pending is true once the underlying service
                 * has been closed until the client library calls the
                 * CLOSE_DELIVERED ioctl, signalling close_event.
                 */
                if (user_service->close_pending &&
                    wait_for_completion_interruptible(&user_service->close_event))
                        status = -EAGAIN;
                break;
        }

        case VCHIQ_IOC_USE_SERVICE:
        case VCHIQ_IOC_RELEASE_SERVICE: {
                unsigned int handle = (unsigned int)arg;

                service = find_service_for_instance(instance, handle);
                if (service) {
                        ret = (cmd == VCHIQ_IOC_USE_SERVICE) ?
                                vchiq_use_service_internal(service) :
                                vchiq_release_service_internal(service);
                        if (ret) {
                                dev_err(instance->state->dev,
                                        "suspend: cmd %s returned error %ld for service %p4cc:%03d\n",
                                        (cmd == VCHIQ_IOC_USE_SERVICE) ?
                                        "VCHIQ_IOC_USE_SERVICE" :
                                        "VCHIQ_IOC_RELEASE_SERVICE",
                                        ret, &service->base.fourcc,
                                        service->client_id);
                        }
                } else {
                        ret = -EINVAL;
                }
        } break;

        case VCHIQ_IOC_QUEUE_MESSAGE: {
                struct vchiq_queue_message args;

                if (copy_from_user(&args, (const void __user *)arg,
                                   sizeof(args))) {
                        ret = -EFAULT;
                        break;
                }

                service = find_service_for_instance(instance, args.handle);

                if (service && (args.count <= MAX_ELEMENTS)) {
                        /* Copy elements into kernel space */
                        struct vchiq_element elements[MAX_ELEMENTS];

                        if (copy_from_user(elements, args.elements,
                                           args.count * sizeof(struct vchiq_element)) == 0)
                                ret = vchiq_ioc_queue_message(instance, args.handle, elements,
                                                              args.count);
                        else
                                ret = -EFAULT;
                } else {
                        ret = -EINVAL;
                }
        } break;

        case VCHIQ_IOC_QUEUE_BULK_TRANSMIT:
        case VCHIQ_IOC_QUEUE_BULK_RECEIVE: {
                struct vchiq_queue_bulk_transfer args;
                struct vchiq_queue_bulk_transfer __user *argp;

                enum vchiq_bulk_dir dir =
                        (cmd == VCHIQ_IOC_QUEUE_BULK_TRANSMIT) ?
                        VCHIQ_BULK_TRANSMIT : VCHIQ_BULK_RECEIVE;

                argp = (void __user *)arg;
                if (copy_from_user(&args, argp, sizeof(args))) {
                        ret = -EFAULT;
                        break;
                }

                ret = vchiq_irq_queue_bulk_tx_rx(instance, &args,
                                                 dir, &argp->mode);
        } break;

        case VCHIQ_IOC_AWAIT_COMPLETION: {
                struct vchiq_await_completion args;
                struct vchiq_await_completion __user *argp;

                argp = (void __user *)arg;
                if (copy_from_user(&args, argp, sizeof(args))) {
                        ret = -EFAULT;
                        break;
                }

                ret = vchiq_ioc_await_completion(instance, &args,
                                                 &argp->msgbufcount);
        } break;

        case VCHIQ_IOC_DEQUEUE_MESSAGE: {
                struct vchiq_dequeue_message args;

                if (copy_from_user(&args, (const void __user *)arg,
                                   sizeof(args))) {
                        ret = -EFAULT;
                        break;
                }

                ret = vchiq_ioc_dequeue_message(instance, &args);
        } break;

        case VCHIQ_IOC_GET_CLIENT_ID: {
                unsigned int handle = (unsigned int)arg;

                ret = vchiq_get_client_id(instance, handle);
        } break;

        case VCHIQ_IOC_GET_CONFIG: {
                struct vchiq_get_config args;
                struct vchiq_config config;

                if (copy_from_user(&args, (const void __user *)arg,
                                   sizeof(args))) {
                        ret = -EFAULT;
                        break;
                }
                if (args.config_size > sizeof(config)) {
                        ret = -EINVAL;
                        break;
                }

                vchiq_get_config(&config);
                if (copy_to_user(args.pconfig, &config, args.config_size)) {
                        ret = -EFAULT;
                        break;
                }
        } break;

        case VCHIQ_IOC_SET_SERVICE_OPTION: {
                struct vchiq_set_service_option args;

                if (copy_from_user(&args, (const void __user *)arg,
                                   sizeof(args))) {
                        ret = -EFAULT;
                        break;
                }

                service = find_service_for_instance(instance, args.handle);
                if (!service) {
                        ret = -EINVAL;
                        break;
                }

                ret = vchiq_set_service_option(instance, args.handle, args.option,
                                               args.value);
        } break;

        case VCHIQ_IOC_LIB_VERSION: {
                unsigned int lib_version = (unsigned int)arg;

                if (lib_version < VCHIQ_VERSION_MIN)
                        ret = -EINVAL;
                else if (lib_version >= VCHIQ_VERSION_CLOSE_DELIVERED)
                        instance->use_close_delivered = 1;
        } break;

        case VCHIQ_IOC_CLOSE_DELIVERED: {
                unsigned int handle = (unsigned int)arg;

                service = find_closed_service_for_instance(instance, handle);
                if (service) {
                        struct user_service *user_service =
                                (struct user_service *)service->base.userdata;
                        close_delivered(user_service);
                } else {
                        ret = -EINVAL;
                }
        } break;

        default:
                ret = -ENOTTY;
                break;
        }

        if (service)
                vchiq_service_put(service);

        if (ret == 0) {
                if (status == -EINVAL)
                        ret = -EIO;
                else if (status == -EAGAIN)
                        ret = -EINTR;
        }

        if (!status && (ret < 0) && (ret != -EINTR) && (ret != -EWOULDBLOCK)) {
                dev_dbg(instance->state->dev,
                        "arm: ioctl instance %p, cmd %s -> status %d, %ld\n",
                        instance, (_IOC_NR(cmd) <= VCHIQ_IOC_MAX) ?
                        ioctl_names[_IOC_NR(cmd)] : "<invalid>", status, ret);
        } else {
                dev_dbg(instance->state->dev,
                        "arm: ioctl instance %p, cmd %s -> status %d\n, %ld\n",
                        instance, (_IOC_NR(cmd) <= VCHIQ_IOC_MAX) ?
                        ioctl_names[_IOC_NR(cmd)] : "<invalid>", status, ret);
        }

        return ret;
}

#if defined(CONFIG_COMPAT)

struct vchiq_service_params32 {
        int fourcc;
        compat_uptr_t callback;
        compat_uptr_t userdata;
        short version; /* Increment for non-trivial changes */
        short version_min; /* Update for incompatible changes */
};

struct vchiq_create_service32 {
        struct vchiq_service_params32 params;
        int is_open;
        int is_vchi;
        unsigned int handle; /* OUT */
};

#define VCHIQ_IOC_CREATE_SERVICE32 \
        _IOWR(VCHIQ_IOC_MAGIC, 2, struct vchiq_create_service32)

static long
vchiq_compat_ioctl_create_service(struct file *file, unsigned int cmd,
                                  struct vchiq_create_service32 __user *ptrargs32)
{
        struct vchiq_create_service args;
        struct vchiq_create_service32 args32;
        struct vchiq_instance *instance = file->private_data;
        long ret;

        if (copy_from_user(&args32, ptrargs32, sizeof(args32)))
                return -EFAULT;

        args = (struct vchiq_create_service) {
                .params = {
                        .fourcc      = args32.params.fourcc,
                        .callback    = compat_ptr(args32.params.callback),
                        .userdata    = compat_ptr(args32.params.userdata),
                        .version     = args32.params.version,
                        .version_min = args32.params.version_min,
                },
                .is_open = args32.is_open,
                .is_vchi = args32.is_vchi,
                .handle  = args32.handle,
        };

        ret = vchiq_ioc_create_service(instance, &args);
        if (ret < 0)
                return ret;

        if (put_user(args.handle, &ptrargs32->handle)) {
                vchiq_remove_service(instance, args.handle);
                return -EFAULT;
        }

        return 0;
}

struct vchiq_element32 {
        compat_uptr_t data;
        unsigned int size;
};

struct vchiq_queue_message32 {
        unsigned int handle;
        unsigned int count;
        compat_uptr_t elements;
};

#define VCHIQ_IOC_QUEUE_MESSAGE32 \
        _IOW(VCHIQ_IOC_MAGIC,  4, struct vchiq_queue_message32)

static long
vchiq_compat_ioctl_queue_message(struct file *file,
                                 unsigned int cmd,
                                 struct vchiq_queue_message32 __user *arg)
{
        struct vchiq_queue_message args;
        struct vchiq_queue_message32 args32;
        struct vchiq_service *service;
        struct vchiq_instance *instance = file->private_data;
        int ret;

        if (copy_from_user(&args32, arg, sizeof(args32)))
                return -EFAULT;

        args = (struct vchiq_queue_message) {
                .handle   = args32.handle,
                .count    = args32.count,
                .elements = compat_ptr(args32.elements),
        };

        if (args32.count > MAX_ELEMENTS)
                return -EINVAL;

        service = find_service_for_instance(instance, args.handle);
        if (!service)
                return -EINVAL;

        if (args32.elements && args32.count) {
                struct vchiq_element32 element32[MAX_ELEMENTS];
                struct vchiq_element elements[MAX_ELEMENTS];
                unsigned int count;

                if (copy_from_user(&element32, args.elements,
                                   sizeof(element32))) {
                        vchiq_service_put(service);
                        return -EFAULT;
                }

                for (count = 0; count < args32.count; count++) {
                        elements[count].data =
                                compat_ptr(element32[count].data);
                        elements[count].size = element32[count].size;
                }
                ret = vchiq_ioc_queue_message(instance, args.handle, elements,
                                              args.count);
        } else {
                ret = -EINVAL;
        }
        vchiq_service_put(service);

        return ret;
}

struct vchiq_queue_bulk_transfer32 {
        unsigned int handle;
        compat_uptr_t data;
        unsigned int size;
        compat_uptr_t userdata;
        enum vchiq_bulk_mode mode;
};

#define VCHIQ_IOC_QUEUE_BULK_TRANSMIT32 \
        _IOWR(VCHIQ_IOC_MAGIC, 5, struct vchiq_queue_bulk_transfer32)
#define VCHIQ_IOC_QUEUE_BULK_RECEIVE32 \
        _IOWR(VCHIQ_IOC_MAGIC, 6, struct vchiq_queue_bulk_transfer32)

static long
vchiq_compat_ioctl_queue_bulk(struct file *file,
                              unsigned int cmd,
                              struct vchiq_queue_bulk_transfer32 __user *argp)
{
        struct vchiq_queue_bulk_transfer32 args32;
        struct vchiq_queue_bulk_transfer args;
        enum vchiq_bulk_dir dir = (cmd == VCHIQ_IOC_QUEUE_BULK_TRANSMIT32) ?
                                  VCHIQ_BULK_TRANSMIT : VCHIQ_BULK_RECEIVE;

        if (copy_from_user(&args32, argp, sizeof(args32)))
                return -EFAULT;

        args = (struct vchiq_queue_bulk_transfer) {
                .handle   = args32.handle,
                .data     = compat_ptr(args32.data),
                .size     = args32.size,
                .userdata = compat_ptr(args32.userdata),
                .mode     = args32.mode,
        };

        return vchiq_irq_queue_bulk_tx_rx(file->private_data, &args,
                                          dir, &argp->mode);
}

struct vchiq_await_completion32 {
        unsigned int count;
        compat_uptr_t buf;
        unsigned int msgbufsize;
        unsigned int msgbufcount; /* IN/OUT */
        compat_uptr_t msgbufs;
};

#define VCHIQ_IOC_AWAIT_COMPLETION32 \
        _IOWR(VCHIQ_IOC_MAGIC, 7, struct vchiq_await_completion32)

static long
vchiq_compat_ioctl_await_completion(struct file *file,
                                    unsigned int cmd,
                                    struct vchiq_await_completion32 __user *argp)
{
        struct vchiq_await_completion args;
        struct vchiq_await_completion32 args32;

        if (copy_from_user(&args32, argp, sizeof(args32)))
                return -EFAULT;

        args = (struct vchiq_await_completion) {
                .count          = args32.count,
                .buf            = compat_ptr(args32.buf),
                .msgbufsize     = args32.msgbufsize,
                .msgbufcount    = args32.msgbufcount,
                .msgbufs        = compat_ptr(args32.msgbufs),
        };

        return vchiq_ioc_await_completion(file->private_data, &args,
                                          &argp->msgbufcount);
}

struct vchiq_dequeue_message32 {
        unsigned int handle;
        int blocking;
        unsigned int bufsize;
        compat_uptr_t buf;
};

#define VCHIQ_IOC_DEQUEUE_MESSAGE32 \
        _IOWR(VCHIQ_IOC_MAGIC, 8, struct vchiq_dequeue_message32)

static long
vchiq_compat_ioctl_dequeue_message(struct file *file,
                                   unsigned int cmd,
                                   struct vchiq_dequeue_message32 __user *arg)
{
        struct vchiq_dequeue_message32 args32;
        struct vchiq_dequeue_message args;

        if (copy_from_user(&args32, arg, sizeof(args32)))
                return -EFAULT;

        args = (struct vchiq_dequeue_message) {
                .handle         = args32.handle,
                .blocking       = args32.blocking,
                .bufsize        = args32.bufsize,
                .buf            = compat_ptr(args32.buf),
        };

        return vchiq_ioc_dequeue_message(file->private_data, &args);
}

struct vchiq_get_config32 {
        unsigned int config_size;
        compat_uptr_t pconfig;
};

#define VCHIQ_IOC_GET_CONFIG32 \
        _IOWR(VCHIQ_IOC_MAGIC, 10, struct vchiq_get_config32)

static long
vchiq_compat_ioctl_get_config(struct file *file,
                              unsigned int cmd,
                              struct vchiq_get_config32 __user *arg)
{
        struct vchiq_get_config32 args32;
        struct vchiq_config config;
        void __user *ptr;

        if (copy_from_user(&args32, arg, sizeof(args32)))
                return -EFAULT;
        if (args32.config_size > sizeof(config))
                return -EINVAL;

        vchiq_get_config(&config);
        ptr = compat_ptr(args32.pconfig);
        if (copy_to_user(ptr, &config, args32.config_size))
                return -EFAULT;

        return 0;
}

static long
vchiq_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
        void __user *argp = compat_ptr(arg);

        switch (cmd) {
        case VCHIQ_IOC_CREATE_SERVICE32:
                return vchiq_compat_ioctl_create_service(file, cmd, argp);
        case VCHIQ_IOC_QUEUE_MESSAGE32:
                return vchiq_compat_ioctl_queue_message(file, cmd, argp);
        case VCHIQ_IOC_QUEUE_BULK_TRANSMIT32:
        case VCHIQ_IOC_QUEUE_BULK_RECEIVE32:
                return vchiq_compat_ioctl_queue_bulk(file, cmd, argp);
        case VCHIQ_IOC_AWAIT_COMPLETION32:
                return vchiq_compat_ioctl_await_completion(file, cmd, argp);
        case VCHIQ_IOC_DEQUEUE_MESSAGE32:
                return vchiq_compat_ioctl_dequeue_message(file, cmd, argp);
        case VCHIQ_IOC_GET_CONFIG32:
                return vchiq_compat_ioctl_get_config(file, cmd, argp);
        default:
                return vchiq_ioctl(file, cmd, (unsigned long)argp);
        }
}

#endif

static int vchiq_open(struct inode *inode, struct file *file)
{
        struct miscdevice *vchiq_miscdev = file->private_data;
        struct vchiq_drv_mgmt *mgmt = dev_get_drvdata(vchiq_miscdev->parent);
        struct vchiq_state *state = &mgmt->state;
        struct vchiq_instance *instance;

        dev_dbg(state->dev, "arm: vchiq open\n");

        if (!vchiq_remote_initialised(state)) {
                dev_dbg(state->dev, "arm: vchiq has no connection to VideoCore\n");
                return -ENOTCONN;
        }

        instance = kzalloc_obj(*instance);
        if (!instance)
                return -ENOMEM;

        instance->state = state;
        instance->pid = current->tgid;

        vchiq_debugfs_add_instance(instance);

        init_completion(&instance->insert_event);
        init_completion(&instance->remove_event);
        mutex_init(&instance->completion_mutex);
        mutex_init(&instance->bulk_waiter_list_mutex);
        INIT_LIST_HEAD(&instance->bulk_waiter_list);

        file->private_data = instance;

        return 0;
}

static int vchiq_release(struct inode *inode, struct file *file)
{
        struct vchiq_instance *instance = file->private_data;
        struct vchiq_state *state = instance->state;
        struct vchiq_service *service;
        int ret = 0;
        int i;

        dev_dbg(state->dev, "arm: instance=%p\n", instance);

        if (!vchiq_remote_initialised(state)) {
                ret = -EPERM;
                goto out;
        }

        /* Ensure videocore is awake to allow termination. */
        vchiq_use_internal(instance->state, NULL, USE_TYPE_VCHIQ);

        mutex_lock(&instance->completion_mutex);

        /* Wake the completion thread and ask it to exit */
        instance->closing = 1;
        complete(&instance->insert_event);

        mutex_unlock(&instance->completion_mutex);

        /* Wake the slot handler if the completion queue is full. */
        complete(&instance->remove_event);

        /* Mark all services for termination... */
        i = 0;
        while ((service = next_service_by_instance(state, instance, &i))) {
                struct user_service *user_service = service->base.userdata;

                /* Wake the slot handler if the msg queue is full. */
                complete(&user_service->remove_event);

                vchiq_terminate_service_internal(service);
                vchiq_service_put(service);
        }

        /* ...and wait for them to die */
        i = 0;
        while ((service = next_service_by_instance(state, instance, &i))) {
                struct user_service *user_service = service->base.userdata;

                wait_for_completion(&service->remove_event);

                if (WARN_ON(service->srvstate != VCHIQ_SRVSTATE_FREE)) {
                        vchiq_service_put(service);
                        break;
                }

                spin_lock(&service->state->msg_queue_spinlock);

                while (user_service->msg_remove != user_service->msg_insert) {
                        struct vchiq_header *header;
                        int m = user_service->msg_remove & (MSG_QUEUE_SIZE - 1);

                        header = user_service->msg_queue[m];
                        user_service->msg_remove++;
                        spin_unlock(&service->state->msg_queue_spinlock);

                        if (header)
                                vchiq_release_message(instance, service->handle, header);
                        spin_lock(&service->state->msg_queue_spinlock);
                }

                spin_unlock(&service->state->msg_queue_spinlock);

                vchiq_service_put(service);
        }

        /* Release any closed services */
        while (instance->completion_remove != instance->completion_insert) {
                struct vchiq_completion_data_kernel *completion;
                struct vchiq_service *service;

                completion = &instance->completions[instance->completion_remove
                                                    & (MAX_COMPLETIONS - 1)];
                service = completion->service_userdata;
                if (completion->reason == VCHIQ_SERVICE_CLOSED) {
                        struct user_service *user_service =
                                                        service->base.userdata;

                        /* Wake any blocked user-thread */
                        if (instance->use_close_delivered)
                                complete(&user_service->close_event);
                        vchiq_service_put(service);
                }
                instance->completion_remove++;
        }

        /* Release the PEER service count. */
        vchiq_release_internal(instance->state, NULL);

        free_bulk_waiter(instance);

        vchiq_debugfs_remove_instance(instance);

        kfree(instance);
        file->private_data = NULL;

out:
        return ret;
}

static const struct file_operations
vchiq_fops = {
        .owner = THIS_MODULE,
        .unlocked_ioctl = vchiq_ioctl,
#if defined(CONFIG_COMPAT)
        .compat_ioctl = vchiq_compat_ioctl,
#endif
        .open = vchiq_open,
        .release = vchiq_release,
};

static struct miscdevice vchiq_miscdev = {
        .fops = &vchiq_fops,
        .minor = MISC_DYNAMIC_MINOR,
        .name = "vchiq",

};

/**
 *      vchiq_register_chrdev - Register the char driver for vchiq
 *                              and create the necessary class and
 *                              device files in userspace.
 *      @parent:        The parent of the char device.
 *
 *      Returns 0 on success else returns the error code.
 */
int vchiq_register_chrdev(struct device *parent)
{
        vchiq_miscdev.parent = parent;

        return misc_register(&vchiq_miscdev);
}

/**
 *      vchiq_deregister_chrdev - Deregister and cleanup the vchiq char
 *                                driver and device files
 */
void vchiq_deregister_chrdev(void)
{
        misc_deregister(&vchiq_miscdev);
}