// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Char device for device raw access
 *
 * Copyright (C) 2005-2007  Kristian Hoegsberg <krh@bitplanet.net>
 */

#include <linux/bug.h>
#include <linux/compat.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/firewire.h>
#include <linux/firewire-cdev.h>
#include <linux/irqflags.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/kref.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/poll.h>
#include <linux/sched.h> /* required for linux/wait.h */
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/time.h>
#include <linux/uaccess.h>
#include <linux/vmalloc.h>
#include <linux/wait.h>
#include <linux/workqueue.h>


#include "core.h"
#include <trace/events/firewire.h>

#include "packet-header-definitions.h"

/*
 * ABI version history is documented in linux/firewire-cdev.h.
 */
#define FW_CDEV_KERNEL_VERSION                  6
#define FW_CDEV_VERSION_EVENT_REQUEST2          4
#define FW_CDEV_VERSION_ALLOCATE_REGION_END     4
#define FW_CDEV_VERSION_AUTO_FLUSH_ISO_OVERFLOW 5
#define FW_CDEV_VERSION_EVENT_ASYNC_TSTAMP      6

static DEFINE_SPINLOCK(phy_receiver_list_lock);
static LIST_HEAD(phy_receiver_list);

struct client {
        u32 version;
        struct fw_device *device;

        spinlock_t lock;
        bool in_shutdown;
        struct xarray resource_xa;
        struct list_head event_list;
        wait_queue_head_t wait;
        wait_queue_head_t tx_flush_wait;
        u64 bus_reset_closure;

        struct fw_iso_context *iso_context;
        struct mutex iso_context_mutex;
        u64 iso_closure;
        struct fw_iso_buffer buffer;
        unsigned long vm_start;

        struct list_head phy_receiver_link;
        u64 phy_receiver_closure;

        struct list_head link;
        struct kref kref;
};

static inline void client_get(struct client *client)
{
        kref_get(&client->kref);
}

static void client_release(struct kref *kref)
{
        struct client *client = container_of(kref, struct client, kref);

        fw_device_put(client->device);
        kfree(client);
}

static void client_put(struct client *client)
{
        kref_put(&client->kref, client_release);
}

struct client_resource;
typedef void (*client_resource_release_fn_t)(struct client *,
                                             struct client_resource *);
struct client_resource {
        client_resource_release_fn_t release;
        int handle;
};

struct address_handler_resource {
        struct client_resource resource;
        struct fw_address_handler handler;
        __u64 closure;
        struct client *client;
};

struct outbound_transaction_resource {
        struct client_resource resource;
        struct fw_transaction transaction;
};

struct inbound_transaction_resource {
        struct client_resource resource;
        struct fw_card *card;
        struct fw_request *request;
        bool is_fcp;
        void *data;
        size_t length;
};

struct descriptor_resource {
        struct client_resource resource;
        struct fw_descriptor descriptor;
        u32 data[];
};

struct iso_resource {
        struct client_resource resource;
        struct client *client;
        /* Schedule work and access todo only with client->lock held. */
        struct delayed_work work;
        enum {ISO_RES_ALLOC, ISO_RES_REALLOC, ISO_RES_DEALLOC,
              ISO_RES_ALLOC_ONCE, ISO_RES_DEALLOC_ONCE,} todo;
        int generation;
        u64 channels;
        s32 bandwidth;
        struct iso_resource_event *e_alloc, *e_dealloc;
};

static struct address_handler_resource *to_address_handler_resource(struct client_resource *resource)
{
        return container_of(resource, struct address_handler_resource, resource);
}

static struct inbound_transaction_resource *to_inbound_transaction_resource(struct client_resource *resource)
{
        return container_of(resource, struct inbound_transaction_resource, resource);
}

static struct descriptor_resource *to_descriptor_resource(struct client_resource *resource)
{
        return container_of(resource, struct descriptor_resource, resource);
}

static struct iso_resource *to_iso_resource(struct client_resource *resource)
{
        return container_of(resource, struct iso_resource, resource);
}

static void release_iso_resource(struct client *, struct client_resource *);

static int is_iso_resource(const struct client_resource *resource)
{
        return resource->release == release_iso_resource;
}

static void release_transaction(struct client *client,
                                struct client_resource *resource);

static int is_outbound_transaction_resource(const struct client_resource *resource)
{
        return resource->release == release_transaction;
}

static void schedule_iso_resource(struct iso_resource *r, unsigned long delay)
{
        client_get(r->client);
        if (!queue_delayed_work(fw_workqueue, &r->work, delay))
                client_put(r->client);
}

/*
 * dequeue_event() just kfree()'s the event, so the event has to be
 * the first field in a struct XYZ_event.
 */
struct event {
        struct { void *data; size_t size; } v[2];
        struct list_head link;
};

struct bus_reset_event {
        struct event event;
        struct fw_cdev_event_bus_reset reset;
};

struct outbound_transaction_event {
        struct event event;
        struct client *client;
        struct outbound_transaction_resource r;
        union {
                struct fw_cdev_event_response without_tstamp;
                struct fw_cdev_event_response2 with_tstamp;
        } rsp;
};

struct inbound_transaction_event {
        struct event event;
        union {
                struct fw_cdev_event_request request;
                struct fw_cdev_event_request2 request2;
                struct fw_cdev_event_request3 with_tstamp;
        } req;
};

struct iso_interrupt_event {
        struct event event;
        struct fw_cdev_event_iso_interrupt interrupt;
};

struct iso_interrupt_mc_event {
        struct event event;
        struct fw_cdev_event_iso_interrupt_mc interrupt;
};

struct iso_resource_event {
        struct event event;
        struct fw_cdev_event_iso_resource iso_resource;
};

struct outbound_phy_packet_event {
        struct event event;
        struct client *client;
        struct fw_packet p;
        union {
                struct fw_cdev_event_phy_packet without_tstamp;
                struct fw_cdev_event_phy_packet2 with_tstamp;
        } phy_packet;
};

struct inbound_phy_packet_event {
        struct event event;
        union {
                struct fw_cdev_event_phy_packet without_tstamp;
                struct fw_cdev_event_phy_packet2 with_tstamp;
        } phy_packet;
};

#ifdef CONFIG_COMPAT
static void __user *u64_to_uptr(u64 value)
{
        if (in_compat_syscall())
                return compat_ptr(value);
        else
                return (void __user *)(unsigned long)value;
}

static u64 uptr_to_u64(void __user *ptr)
{
        if (in_compat_syscall())
                return ptr_to_compat(ptr);
        else
                return (u64)(unsigned long)ptr;
}
#else
static inline void __user *u64_to_uptr(u64 value)
{
        return (void __user *)(unsigned long)value;
}

static inline u64 uptr_to_u64(void __user *ptr)
{
        return (u64)(unsigned long)ptr;
}
#endif /* CONFIG_COMPAT */

static int fw_device_op_open(struct inode *inode, struct file *file)
{
        struct fw_device *device;
        struct client *client;

        device = fw_device_get_by_devt(inode->i_rdev);
        if (device == NULL)
                return -ENODEV;

        if (fw_device_is_shutdown(device)) {
                fw_device_put(device);
                return -ENODEV;
        }

        client = kzalloc_obj(*client);
        if (client == NULL) {
                fw_device_put(device);
                return -ENOMEM;
        }

        client->device = device;
        spin_lock_init(&client->lock);
        xa_init_flags(&client->resource_xa, XA_FLAGS_ALLOC1 | XA_FLAGS_LOCK_BH);
        INIT_LIST_HEAD(&client->event_list);
        init_waitqueue_head(&client->wait);
        init_waitqueue_head(&client->tx_flush_wait);
        INIT_LIST_HEAD(&client->phy_receiver_link);
        INIT_LIST_HEAD(&client->link);
        kref_init(&client->kref);
        mutex_init(&client->iso_context_mutex);

        file->private_data = client;

        return nonseekable_open(inode, file);
}

static void queue_event(struct client *client, struct event *event,
                        void *data0, size_t size0, void *data1, size_t size1)
{
        event->v[0].data = data0;
        event->v[0].size = size0;
        event->v[1].data = data1;
        event->v[1].size = size1;

        scoped_guard(spinlock_irqsave, &client->lock) {
                if (client->in_shutdown)
                        kfree(event);
                else
                        list_add_tail(&event->link, &client->event_list);
        }

        wake_up_interruptible(&client->wait);
}

static int dequeue_event(struct client *client,
                         char __user *buffer, size_t count)
{
        struct event *event;
        size_t size, total;
        int i, ret;

        ret = wait_event_interruptible(client->wait,
                        !list_empty(&client->event_list) ||
                        fw_device_is_shutdown(client->device));
        if (ret < 0)
                return ret;

        if (list_empty(&client->event_list) &&
                       fw_device_is_shutdown(client->device))
                return -ENODEV;

        scoped_guard(spinlock_irq, &client->lock) {
                event = list_first_entry(&client->event_list, struct event, link);
                list_del(&event->link);
        }

        total = 0;
        for (i = 0; i < ARRAY_SIZE(event->v) && total < count; i++) {
                size = min(event->v[i].size, count - total);
                if (copy_to_user(buffer + total, event->v[i].data, size)) {
                        ret = -EFAULT;
                        goto out;
                }
                total += size;
        }
        ret = total;

 out:
        kfree(event);

        return ret;
}

static ssize_t fw_device_op_read(struct file *file, char __user *buffer,
                                 size_t count, loff_t *offset)
{
        struct client *client = file->private_data;

        return dequeue_event(client, buffer, count);
}

static void fill_bus_reset_event(struct fw_cdev_event_bus_reset *event,
                                 struct client *client)
{
        struct fw_card *card = client->device->card;

        guard(spinlock_irq)(&card->lock);

        event->closure       = client->bus_reset_closure;
        event->type          = FW_CDEV_EVENT_BUS_RESET;
        event->generation    = client->device->generation;
        event->node_id       = client->device->node_id;
        event->local_node_id = card->local_node->node_id;
        event->bm_node_id    = card->bm_node_id;
        event->irm_node_id   = card->irm_node->node_id;
        event->root_node_id  = card->root_node->node_id;
}

static void for_each_client(struct fw_device *device,
                            void (*callback)(struct client *client))
{
        struct client *c;

        guard(mutex)(&device->client_list_mutex);

        list_for_each_entry(c, &device->client_list, link)
                callback(c);
}

static void queue_bus_reset_event(struct client *client)
{
        struct bus_reset_event *e;
        struct client_resource *resource;
        unsigned long index;

        e = kzalloc_obj(*e);
        if (e == NULL)
                return;

        fill_bus_reset_event(&e->reset, client);

        queue_event(client, &e->event,
                    &e->reset, sizeof(e->reset), NULL, 0);

        guard(spinlock_irq)(&client->lock);

        xa_for_each(&client->resource_xa, index, resource) {
                if (is_iso_resource(resource))
                        schedule_iso_resource(to_iso_resource(resource), 0);
        }
}

void fw_device_cdev_update(struct fw_device *device)
{
        for_each_client(device, queue_bus_reset_event);
}

static void wake_up_client(struct client *client)
{
        wake_up_interruptible(&client->wait);
}

void fw_device_cdev_remove(struct fw_device *device)
{
        for_each_client(device, wake_up_client);
}

union ioctl_arg {
        struct fw_cdev_get_info                 get_info;
        struct fw_cdev_send_request             send_request;
        struct fw_cdev_allocate                 allocate;
        struct fw_cdev_deallocate               deallocate;
        struct fw_cdev_send_response            send_response;
        struct fw_cdev_initiate_bus_reset       initiate_bus_reset;
        struct fw_cdev_add_descriptor           add_descriptor;
        struct fw_cdev_remove_descriptor        remove_descriptor;
        struct fw_cdev_create_iso_context       create_iso_context;
        struct fw_cdev_queue_iso                queue_iso;
        struct fw_cdev_start_iso                start_iso;
        struct fw_cdev_stop_iso                 stop_iso;
        struct fw_cdev_get_cycle_timer          get_cycle_timer;
        struct fw_cdev_allocate_iso_resource    allocate_iso_resource;
        struct fw_cdev_send_stream_packet       send_stream_packet;
        struct fw_cdev_get_cycle_timer2         get_cycle_timer2;
        struct fw_cdev_send_phy_packet          send_phy_packet;
        struct fw_cdev_receive_phy_packets      receive_phy_packets;
        struct fw_cdev_set_iso_channels         set_iso_channels;
        struct fw_cdev_flush_iso                flush_iso;
};

static int ioctl_get_info(struct client *client, union ioctl_arg *arg)
{
        struct fw_cdev_get_info *a = &arg->get_info;
        struct fw_cdev_event_bus_reset bus_reset;
        unsigned long ret = 0;

        client->version = a->version;
        a->version = FW_CDEV_KERNEL_VERSION;
        a->card = client->device->card->index;

        scoped_guard(rwsem_read, &fw_device_rwsem) {
                if (a->rom != 0) {
                        size_t want = a->rom_length;
                        size_t have = client->device->config_rom_length * 4;

                        ret = copy_to_user(u64_to_uptr(a->rom), client->device->config_rom,
                                           min(want, have));
                        if (ret != 0)
                                return -EFAULT;
                }
                a->rom_length = client->device->config_rom_length * 4;
        }

        guard(mutex)(&client->device->client_list_mutex);

        client->bus_reset_closure = a->bus_reset_closure;
        if (a->bus_reset != 0) {
                fill_bus_reset_event(&bus_reset, client);
                /* unaligned size of bus_reset is 36 bytes */
                ret = copy_to_user(u64_to_uptr(a->bus_reset), &bus_reset, 36);
        }
        if (ret == 0 && list_empty(&client->link))
                list_add_tail(&client->link, &client->device->client_list);

        return ret ? -EFAULT : 0;
}

static int add_client_resource(struct client *client, struct client_resource *resource,
                               gfp_t gfp_mask)
{
        int ret;

        scoped_guard(spinlock_irqsave, &client->lock) {
                u32 index;

                if (client->in_shutdown) {
                        ret = -ECANCELED;
                } else {
                        if (gfpflags_allow_blocking(gfp_mask)) {
                                ret = xa_alloc(&client->resource_xa, &index, resource, xa_limit_32b,
                                               GFP_NOWAIT);
                        } else {
                                ret = xa_alloc_bh(&client->resource_xa, &index, resource,
                                                  xa_limit_32b, GFP_NOWAIT);
                        }
                }
                if (ret >= 0) {
                        resource->handle = index;
                        client_get(client);
                        if (is_iso_resource(resource))
                                schedule_iso_resource(to_iso_resource(resource), 0);
                }
        }

        return ret < 0 ? ret : 0;
}

static int release_client_resource(struct client *client, u32 handle,
                                   client_resource_release_fn_t release,
                                   struct client_resource **return_resource)
{
        unsigned long index = handle;
        struct client_resource *resource;

        scoped_guard(spinlock_irq, &client->lock) {
                if (client->in_shutdown)
                        return -EINVAL;

                resource = xa_load(&client->resource_xa, index);
                if (!resource || resource->release != release)
                        return -EINVAL;

                xa_erase(&client->resource_xa, handle);
        }

        if (return_resource)
                *return_resource = resource;
        else
                resource->release(client, resource);

        client_put(client);

        return 0;
}

static void release_transaction(struct client *client,
                                struct client_resource *resource)
{
}

static void complete_transaction(struct fw_card *card, int rcode, u32 request_tstamp,
                                 u32 response_tstamp, void *payload, size_t length, void *data)
{
        struct outbound_transaction_event *e = data;
        struct client *client = e->client;
        unsigned long index = e->r.resource.handle;

        scoped_guard(spinlock_irqsave, &client->lock) {
                xa_erase(&client->resource_xa, index);
                if (client->in_shutdown)
                        wake_up(&client->tx_flush_wait);
        }

        switch (e->rsp.without_tstamp.type) {
        case FW_CDEV_EVENT_RESPONSE:
        {
                struct fw_cdev_event_response *rsp = &e->rsp.without_tstamp;

                if (length < rsp->length)
                        rsp->length = length;
                if (rcode == RCODE_COMPLETE)
                        memcpy(rsp->data, payload, rsp->length);

                rsp->rcode = rcode;

                // In the case that sizeof(*rsp) doesn't align with the position of the
                // data, and the read is short, preserve an extra copy of the data
                // to stay compatible with a pre-2.6.27 bug.  Since the bug is harmless
                // for short reads and some apps depended on it, this is both safe
                // and prudent for compatibility.
                if (rsp->length <= sizeof(*rsp) - offsetof(typeof(*rsp), data))
                        queue_event(client, &e->event, rsp, sizeof(*rsp), rsp->data, rsp->length);
                else
                        queue_event(client, &e->event, rsp, sizeof(*rsp) + rsp->length, NULL, 0);

                break;
        }
        case FW_CDEV_EVENT_RESPONSE2:
        {
                struct fw_cdev_event_response2 *rsp = &e->rsp.with_tstamp;

                if (length < rsp->length)
                        rsp->length = length;
                if (rcode == RCODE_COMPLETE)
                        memcpy(rsp->data, payload, rsp->length);

                rsp->rcode = rcode;
                rsp->request_tstamp = request_tstamp;
                rsp->response_tstamp = response_tstamp;

                queue_event(client, &e->event, rsp, sizeof(*rsp) + rsp->length, NULL, 0);

                break;
        }
        default:
                WARN_ON(1);
                break;
        }

        // Drop the xarray's reference.
        client_put(client);
}

static int init_request(struct client *client,
                        struct fw_cdev_send_request *request,
                        int destination_id, int speed)
{
        struct outbound_transaction_event *e;
        void *payload;
        int ret;

        if (request->tcode != TCODE_STREAM_DATA &&
            (request->length > 4096 || request->length > 512 << speed))
                return -EIO;

        if (request->tcode == TCODE_WRITE_QUADLET_REQUEST &&
            request->length < 4)
                return -EINVAL;

        e = kmalloc(sizeof(*e) + request->length, GFP_KERNEL);
        if (e == NULL)
                return -ENOMEM;
        e->client = client;

        if (client->version < FW_CDEV_VERSION_EVENT_ASYNC_TSTAMP) {
                struct fw_cdev_event_response *rsp = &e->rsp.without_tstamp;

                rsp->type = FW_CDEV_EVENT_RESPONSE;
                rsp->length = request->length;
                rsp->closure = request->closure;
                payload = rsp->data;
        } else {
                struct fw_cdev_event_response2 *rsp = &e->rsp.with_tstamp;

                rsp->type = FW_CDEV_EVENT_RESPONSE2;
                rsp->length = request->length;
                rsp->closure = request->closure;
                payload = rsp->data;
        }

        if (request->data && copy_from_user(payload, u64_to_uptr(request->data), request->length)) {
                ret = -EFAULT;
                goto failed;
        }

        e->r.resource.release = release_transaction;
        ret = add_client_resource(client, &e->r.resource, GFP_KERNEL);
        if (ret < 0)
                goto failed;

        fw_send_request_with_tstamp(client->device->card, &e->r.transaction, request->tcode,
                                    destination_id, request->generation, speed, request->offset,
                                    payload, request->length, complete_transaction, e);
        return 0;

 failed:
        kfree(e);

        return ret;
}

static int ioctl_send_request(struct client *client, union ioctl_arg *arg)
{
        switch (arg->send_request.tcode) {
        case TCODE_WRITE_QUADLET_REQUEST:
        case TCODE_WRITE_BLOCK_REQUEST:
        case TCODE_READ_QUADLET_REQUEST:
        case TCODE_READ_BLOCK_REQUEST:
        case TCODE_LOCK_MASK_SWAP:
        case TCODE_LOCK_COMPARE_SWAP:
        case TCODE_LOCK_FETCH_ADD:
        case TCODE_LOCK_LITTLE_ADD:
        case TCODE_LOCK_BOUNDED_ADD:
        case TCODE_LOCK_WRAP_ADD:
        case TCODE_LOCK_VENDOR_DEPENDENT:
                break;
        default:
                return -EINVAL;
        }

        return init_request(client, &arg->send_request, client->device->node_id,
                            client->device->max_speed);
}

static void release_request(struct client *client,
                            struct client_resource *resource)
{
        struct inbound_transaction_resource *r = to_inbound_transaction_resource(resource);

        if (r->is_fcp)
                fw_request_put(r->request);
        else
                fw_send_response(r->card, r->request, RCODE_CONFLICT_ERROR);

        fw_card_put(r->card);
        kfree(r);
}

static void handle_request(struct fw_card *card, struct fw_request *request,
                           int tcode, int destination, int source,
                           int generation, unsigned long long offset,
                           void *payload, size_t length, void *callback_data)
{
        struct address_handler_resource *handler = callback_data;
        bool is_fcp = is_in_fcp_region(offset, length);
        struct inbound_transaction_resource *r;
        struct inbound_transaction_event *e;
        size_t event_size0;
        int ret;

        /* card may be different from handler->client->device->card */
        fw_card_get(card);

        // Extend the lifetime of data for request so that its payload is safely accessible in
        // the process context for the client.
        if (is_fcp)
                fw_request_get(request);

        r = kmalloc_obj(*r, GFP_ATOMIC);
        e = kmalloc_obj(*e, GFP_ATOMIC);
        if (r == NULL || e == NULL)
                goto failed;

        r->card    = card;
        r->request = request;
        r->is_fcp  = is_fcp;
        r->data    = payload;
        r->length  = length;

        r->resource.release = release_request;
        ret = add_client_resource(handler->client, &r->resource, GFP_ATOMIC);
        if (ret < 0)
                goto failed;

        if (handler->client->version < FW_CDEV_VERSION_EVENT_REQUEST2) {
                struct fw_cdev_event_request *req = &e->req.request;

                if (tcode & 0x10)
                        tcode = TCODE_LOCK_REQUEST;

                req->type       = FW_CDEV_EVENT_REQUEST;
                req->tcode      = tcode;
                req->offset     = offset;
                req->length     = length;
                req->handle     = r->resource.handle;
                req->closure    = handler->closure;
                event_size0     = sizeof(*req);
        } else if (handler->client->version < FW_CDEV_VERSION_EVENT_ASYNC_TSTAMP) {
                struct fw_cdev_event_request2 *req = &e->req.request2;

                req->type       = FW_CDEV_EVENT_REQUEST2;
                req->tcode      = tcode;
                req->offset     = offset;
                req->source_node_id = source;
                req->destination_node_id = destination;
                req->card       = card->index;
                req->generation = generation;
                req->length     = length;
                req->handle     = r->resource.handle;
                req->closure    = handler->closure;
                event_size0     = sizeof(*req);
        } else {
                struct fw_cdev_event_request3 *req = &e->req.with_tstamp;

                req->type       = FW_CDEV_EVENT_REQUEST3;
                req->tcode      = tcode;
                req->offset     = offset;
                req->source_node_id = source;
                req->destination_node_id = destination;
                req->card       = card->index;
                req->generation = generation;
                req->length     = length;
                req->handle     = r->resource.handle;
                req->closure    = handler->closure;
                req->tstamp     = fw_request_get_timestamp(request);
                event_size0     = sizeof(*req);
        }

        queue_event(handler->client, &e->event,
                    &e->req, event_size0, r->data, length);
        return;

 failed:
        kfree(r);
        kfree(e);

        if (!is_fcp)
                fw_send_response(card, request, RCODE_CONFLICT_ERROR);
        else
                fw_request_put(request);

        fw_card_put(card);
}

static void release_address_handler(struct client *client,
                                    struct client_resource *resource)
{
        struct address_handler_resource *r = to_address_handler_resource(resource);

        fw_core_remove_address_handler(&r->handler);
        kfree(r);
}

static int ioctl_allocate(struct client *client, union ioctl_arg *arg)
{
        struct fw_cdev_allocate *a = &arg->allocate;
        struct address_handler_resource *r;
        struct fw_address_region region;
        int ret;

        r = kmalloc_obj(*r);
        if (r == NULL)
                return -ENOMEM;

        region.start = a->offset;
        if (client->version < FW_CDEV_VERSION_ALLOCATE_REGION_END)
                region.end = a->offset + a->length;
        else
                region.end = a->region_end;

        r->handler.length           = a->length;
        r->handler.address_callback = handle_request;
        r->handler.callback_data    = r;
        r->closure   = a->closure;
        r->client    = client;

        ret = fw_core_add_address_handler(&r->handler, &region);
        if (ret < 0) {
                kfree(r);
                return ret;
        }
        a->offset = r->handler.offset;

        r->resource.release = release_address_handler;
        ret = add_client_resource(client, &r->resource, GFP_KERNEL);
        if (ret < 0) {
                release_address_handler(client, &r->resource);
                return ret;
        }
        a->handle = r->resource.handle;

        return 0;
}

static int ioctl_deallocate(struct client *client, union ioctl_arg *arg)
{
        return release_client_resource(client, arg->deallocate.handle,
                                       release_address_handler, NULL);
}

static int ioctl_send_response(struct client *client, union ioctl_arg *arg)
{
        struct fw_cdev_send_response *a = &arg->send_response;
        struct client_resource *resource;
        struct inbound_transaction_resource *r;
        int ret = 0;

        if (release_client_resource(client, a->handle,
                                    release_request, &resource) < 0)
                return -EINVAL;

        r = to_inbound_transaction_resource(resource);
        if (r->is_fcp) {
                fw_request_put(r->request);
                goto out;
        }

        if (a->length != fw_get_response_length(r->request)) {
                ret = -EINVAL;
                fw_request_put(r->request);
                goto out;
        }
        if (copy_from_user(r->data, u64_to_uptr(a->data), a->length)) {
                ret = -EFAULT;
                fw_request_put(r->request);
                goto out;
        }
        fw_send_response(r->card, r->request, a->rcode);
 out:
        fw_card_put(r->card);
        kfree(r);

        return ret;
}

static int ioctl_initiate_bus_reset(struct client *client, union ioctl_arg *arg)
{
        fw_schedule_bus_reset(client->device->card, true,
                        arg->initiate_bus_reset.type == FW_CDEV_SHORT_RESET);
        return 0;
}

static void release_descriptor(struct client *client,
                               struct client_resource *resource)
{
        struct descriptor_resource *r = to_descriptor_resource(resource);

        fw_core_remove_descriptor(&r->descriptor);
        kfree(r);
}

static int ioctl_add_descriptor(struct client *client, union ioctl_arg *arg)
{
        struct fw_cdev_add_descriptor *a = &arg->add_descriptor;
        struct descriptor_resource *r;
        int ret;

        /* Access policy: Allow this ioctl only on local nodes' device files. */
        if (!client->device->is_local)
                return -ENOSYS;

        if (a->length > 256)
                return -EINVAL;

        r = kmalloc_flex(*r, data, a->length);
        if (r == NULL)
                return -ENOMEM;

        if (copy_from_user(r->data, u64_to_uptr(a->data),
                           flex_array_size(r, data, a->length))) {
                ret = -EFAULT;
                goto failed;
        }

        r->descriptor.length    = a->length;
        r->descriptor.immediate = a->immediate;
        r->descriptor.key       = a->key;
        r->descriptor.data      = r->data;

        ret = fw_core_add_descriptor(&r->descriptor);
        if (ret < 0)
                goto failed;

        r->resource.release = release_descriptor;
        ret = add_client_resource(client, &r->resource, GFP_KERNEL);
        if (ret < 0) {
                fw_core_remove_descriptor(&r->descriptor);
                goto failed;
        }
        a->handle = r->resource.handle;

        return 0;
 failed:
        kfree(r);

        return ret;
}

static int ioctl_remove_descriptor(struct client *client, union ioctl_arg *arg)
{
        return release_client_resource(client, arg->remove_descriptor.handle,
                                       release_descriptor, NULL);
}

static void iso_callback(struct fw_iso_context *context, u32 cycle,
                         size_t header_length, void *header, void *data)
{
        struct client *client = data;
        struct iso_interrupt_event *e;

        e = kmalloc(sizeof(*e) + header_length, GFP_KERNEL);
        if (e == NULL)
                return;

        e->interrupt.type      = FW_CDEV_EVENT_ISO_INTERRUPT;
        e->interrupt.closure   = client->iso_closure;
        e->interrupt.cycle     = cycle;
        e->interrupt.header_length = header_length;
        memcpy(e->interrupt.header, header, header_length);
        queue_event(client, &e->event, &e->interrupt,
                    sizeof(e->interrupt) + header_length, NULL, 0);
}

static void iso_mc_callback(struct fw_iso_context *context,
                            dma_addr_t completed, void *data)
{
        struct client *client = data;
        struct iso_interrupt_mc_event *e;

        e = kmalloc_obj(*e);
        if (e == NULL)
                return;

        e->interrupt.type      = FW_CDEV_EVENT_ISO_INTERRUPT_MULTICHANNEL;
        e->interrupt.closure   = client->iso_closure;
        e->interrupt.completed = fw_iso_buffer_lookup(&client->buffer,
                                                      completed);
        queue_event(client, &e->event, &e->interrupt,
                    sizeof(e->interrupt), NULL, 0);
}

static enum dma_data_direction iso_dma_direction(struct fw_iso_context *context)
{
                if (context->type == FW_ISO_CONTEXT_TRANSMIT)
                        return DMA_TO_DEVICE;
                else
                        return DMA_FROM_DEVICE;
}

static int ioctl_create_iso_context(struct client *client, union ioctl_arg *arg)
{
        struct fw_cdev_create_iso_context *a = &arg->create_iso_context;
        struct fw_iso_context *context;
        int ret;

        BUILD_BUG_ON(FW_CDEV_ISO_CONTEXT_TRANSMIT != FW_ISO_CONTEXT_TRANSMIT ||
                     FW_CDEV_ISO_CONTEXT_RECEIVE  != FW_ISO_CONTEXT_RECEIVE  ||
                     FW_CDEV_ISO_CONTEXT_RECEIVE_MULTICHANNEL !=
                                        FW_ISO_CONTEXT_RECEIVE_MULTICHANNEL);

        switch (a->type) {
        case FW_ISO_CONTEXT_TRANSMIT:
                if (a->speed > SCODE_3200 || a->channel > 63)
                        return -EINVAL;
                break;

        case FW_ISO_CONTEXT_RECEIVE:
                if (a->header_size < 4 || (a->header_size & 3) ||
                    a->channel > 63)
                        return -EINVAL;
                break;

        case FW_ISO_CONTEXT_RECEIVE_MULTICHANNEL:
                break;

        default:
                return -EINVAL;
        }

        if (a->type == FW_ISO_CONTEXT_RECEIVE_MULTICHANNEL)
                context = fw_iso_mc_context_create(client->device->card, iso_mc_callback, client);
        else
                context = fw_iso_context_create(client->device->card, a->type, a->channel, a->speed,
                                                a->header_size, iso_callback, client);
        if (IS_ERR(context))
                return PTR_ERR(context);
        if (client->version < FW_CDEV_VERSION_AUTO_FLUSH_ISO_OVERFLOW)
                context->flags |= FW_ISO_CONTEXT_FLAG_DROP_OVERFLOW_HEADERS;

        // We only support one context at this time.
        scoped_guard(mutex, &client->iso_context_mutex) {
                if (client->iso_context != NULL) {
                        fw_iso_context_destroy(context);

                        return -EBUSY;
                }
                // The DMA mapping operation is available if the buffer is already allocated by
                // mmap(2) system call. If not, it is delegated to the system call.
                if (client->buffer.pages && !client->buffer.dma_addrs) {
                        ret = fw_iso_buffer_map_dma(&client->buffer, client->device->card,
                                                    iso_dma_direction(context));
                        if (ret < 0) {
                                fw_iso_context_destroy(context);

                                return ret;
                        }
                }
                client->iso_closure = a->closure;
                client->iso_context = context;
        }

        a->handle = 0;

        return 0;
}

static int ioctl_set_iso_channels(struct client *client, union ioctl_arg *arg)
{
        struct fw_cdev_set_iso_channels *a = &arg->set_iso_channels;
        struct fw_iso_context *ctx = client->iso_context;

        if (ctx == NULL || a->handle != 0)
                return -EINVAL;

        return fw_iso_context_set_channels(ctx, &a->channels);
}

/* Macros for decoding the iso packet control header. */
#define GET_PAYLOAD_LENGTH(v)   ((v) & 0xffff)
#define GET_INTERRUPT(v)        (((v) >> 16) & 0x01)
#define GET_SKIP(v)             (((v) >> 17) & 0x01)
#define GET_TAG(v)              (((v) >> 18) & 0x03)
#define GET_SY(v)               (((v) >> 20) & 0x0f)
#define GET_HEADER_LENGTH(v)    (((v) >> 24) & 0xff)

static int ioctl_queue_iso(struct client *client, union ioctl_arg *arg)
{
        struct fw_cdev_queue_iso *a = &arg->queue_iso;
        struct fw_cdev_iso_packet __user *p, *end, *next;
        struct fw_iso_context *ctx = client->iso_context;
        unsigned long payload, buffer_end, transmit_header_bytes = 0;
        u32 control;
        int count;
        DEFINE_RAW_FLEX(struct fw_iso_packet, u, header, 64);

        if (ctx == NULL || a->handle != 0)
                return -EINVAL;

        /*
         * If the user passes a non-NULL data pointer, has mmap()'ed
         * the iso buffer, and the pointer points inside the buffer,
         * we setup the payload pointers accordingly.  Otherwise we
         * set them both to 0, which will still let packets with
         * payload_length == 0 through.  In other words, if no packets
         * use the indirect payload, the iso buffer need not be mapped
         * and the a->data pointer is ignored.
         */
        payload = (unsigned long)a->data - client->vm_start;
        buffer_end = client->buffer.page_count << PAGE_SHIFT;
        if (a->data == 0 || client->buffer.pages == NULL ||
            payload >= buffer_end) {
                payload = 0;
                buffer_end = 0;
        }

        if (ctx->type == FW_ISO_CONTEXT_RECEIVE_MULTICHANNEL && payload & 3)
                return -EINVAL;

        p = (struct fw_cdev_iso_packet __user *)u64_to_uptr(a->packets);

        end = (void __user *)p + a->size;
        count = 0;
        while (p < end) {
                if (get_user(control, &p->control))
                        return -EFAULT;
                u->payload_length = GET_PAYLOAD_LENGTH(control);
                u->interrupt = GET_INTERRUPT(control);
                u->skip = GET_SKIP(control);
                u->tag = GET_TAG(control);
                u->sy = GET_SY(control);
                u->header_length = GET_HEADER_LENGTH(control);

                switch (ctx->type) {
                case FW_ISO_CONTEXT_TRANSMIT:
                        if (u->header_length & 3)
                                return -EINVAL;
                        transmit_header_bytes = u->header_length;
                        break;

                case FW_ISO_CONTEXT_RECEIVE:
                        if (u->header_length == 0 ||
                            u->header_length % ctx->header_size != 0)
                                return -EINVAL;
                        break;

                case FW_ISO_CONTEXT_RECEIVE_MULTICHANNEL:
                        if (u->payload_length == 0 ||
                            u->payload_length & 3)
                                return -EINVAL;
                        break;
                }

                next = (struct fw_cdev_iso_packet __user *)
                        &p->header[transmit_header_bytes / 4];
                if (next > end)
                        return -EINVAL;
                if (copy_from_user
                    (u->header, p->header, transmit_header_bytes))
                        return -EFAULT;
                if (u->skip && ctx->type == FW_ISO_CONTEXT_TRANSMIT &&
                    u->header_length + u->payload_length > 0)
                        return -EINVAL;
                if (payload + u->payload_length > buffer_end)
                        return -EINVAL;

                if (fw_iso_context_queue(ctx, u, &client->buffer, payload))
                        break;

                p = next;
                payload += u->payload_length;
                count++;
        }
        fw_iso_context_queue_flush(ctx);

        a->size    -= uptr_to_u64(p) - a->packets;
        a->packets  = uptr_to_u64(p);
        a->data     = client->vm_start + payload;

        return count;
}

static int ioctl_start_iso(struct client *client, union ioctl_arg *arg)
{
        struct fw_cdev_start_iso *a = &arg->start_iso;

        BUILD_BUG_ON(
            FW_CDEV_ISO_CONTEXT_MATCH_TAG0 != FW_ISO_CONTEXT_MATCH_TAG0 ||
            FW_CDEV_ISO_CONTEXT_MATCH_TAG1 != FW_ISO_CONTEXT_MATCH_TAG1 ||
            FW_CDEV_ISO_CONTEXT_MATCH_TAG2 != FW_ISO_CONTEXT_MATCH_TAG2 ||
            FW_CDEV_ISO_CONTEXT_MATCH_TAG3 != FW_ISO_CONTEXT_MATCH_TAG3 ||
            FW_CDEV_ISO_CONTEXT_MATCH_ALL_TAGS != FW_ISO_CONTEXT_MATCH_ALL_TAGS);

        if (client->iso_context == NULL || a->handle != 0)
                return -EINVAL;

        if (client->iso_context->type == FW_ISO_CONTEXT_RECEIVE &&
            (a->tags == 0 || a->tags > 15 || a->sync > 15))
                return -EINVAL;

        return fw_iso_context_start(client->iso_context,
                                    a->cycle, a->sync, a->tags);
}

static int ioctl_stop_iso(struct client *client, union ioctl_arg *arg)
{
        struct fw_cdev_stop_iso *a = &arg->stop_iso;

        if (client->iso_context == NULL || a->handle != 0)
                return -EINVAL;

        return fw_iso_context_stop(client->iso_context);
}

static int ioctl_flush_iso(struct client *client, union ioctl_arg *arg)
{
        struct fw_cdev_flush_iso *a = &arg->flush_iso;

        if (client->iso_context == NULL || a->handle != 0)
                return -EINVAL;

        return fw_iso_context_flush_completions(client->iso_context);
}

static int ioctl_get_cycle_timer2(struct client *client, union ioctl_arg *arg)
{
        struct fw_cdev_get_cycle_timer2 *a = &arg->get_cycle_timer2;
        struct fw_card *card = client->device->card;
        struct timespec64 ts = {0, 0};
        u32 cycle_time = 0;
        int ret;

        guard(irq)();

        ret = fw_card_read_cycle_time(card, &cycle_time);
        if (ret < 0)
                return ret;

        switch (a->clk_id) {
        case CLOCK_REALTIME:      ktime_get_real_ts64(&ts);     break;
        case CLOCK_MONOTONIC:     ktime_get_ts64(&ts);          break;
        case CLOCK_MONOTONIC_RAW: ktime_get_raw_ts64(&ts);      break;
        default:
                return -EINVAL;
        }

        a->tv_sec      = ts.tv_sec;
        a->tv_nsec     = ts.tv_nsec;
        a->cycle_timer = cycle_time;

        return 0;
}

static int ioctl_get_cycle_timer(struct client *client, union ioctl_arg *arg)
{
        struct fw_cdev_get_cycle_timer *a = &arg->get_cycle_timer;
        struct fw_cdev_get_cycle_timer2 ct2;

        ct2.clk_id = CLOCK_REALTIME;
        ioctl_get_cycle_timer2(client, (union ioctl_arg *)&ct2);

        a->local_time = ct2.tv_sec * USEC_PER_SEC + ct2.tv_nsec / NSEC_PER_USEC;
        a->cycle_timer = ct2.cycle_timer;

        return 0;
}

static void iso_resource_work(struct work_struct *work)
{
        struct iso_resource_event *e;
        struct iso_resource *r = from_work(r, work, work.work);
        struct client *client = r->client;
        unsigned long index = r->resource.handle;
        int generation, channel, bandwidth, todo;
        bool skip, free, success;

        scoped_guard(spinlock_irq, &client->lock) {
                generation = client->device->generation;
                todo = r->todo;
                // Allow 1000ms grace period for other reallocations.
                if (todo == ISO_RES_ALLOC &&
                    time_is_after_jiffies64(client->device->card->reset_jiffies + secs_to_jiffies(1))) {
                        schedule_iso_resource(r, msecs_to_jiffies(333));
                        skip = true;
                } else {
                        // We could be called twice within the same generation.
                        skip = todo == ISO_RES_REALLOC &&
                               r->generation == generation;
                }
                free = todo == ISO_RES_DEALLOC ||
                       todo == ISO_RES_ALLOC_ONCE ||
                       todo == ISO_RES_DEALLOC_ONCE;
                r->generation = generation;
        }

        if (skip)
                goto out;

        bandwidth = r->bandwidth;

        fw_iso_resource_manage(client->device->card, generation,
                        r->channels, &channel, &bandwidth,
                        todo == ISO_RES_ALLOC ||
                        todo == ISO_RES_REALLOC ||
                        todo == ISO_RES_ALLOC_ONCE);
        /*
         * Is this generation outdated already?  As long as this resource sticks
         * in the xarray, it will be scheduled again for a newer generation or at
         * shutdown.
         */
        if (channel == -EAGAIN &&
            (todo == ISO_RES_ALLOC || todo == ISO_RES_REALLOC))
                goto out;

        success = channel >= 0 || bandwidth > 0;

        scoped_guard(spinlock_irq, &client->lock) {
                // Transit from allocation to reallocation, except if the client
                // requested deallocation in the meantime.
                if (r->todo == ISO_RES_ALLOC)
                        r->todo = ISO_RES_REALLOC;
                // Allocation or reallocation failure?  Pull this resource out of the
                // xarray and prepare for deletion, unless the client is shutting down.
                if (r->todo == ISO_RES_REALLOC && !success &&
                    !client->in_shutdown &&
                    xa_erase(&client->resource_xa, index)) {
                        client_put(client);
                        free = true;
                }
        }

        if (todo == ISO_RES_ALLOC && channel >= 0)
                r->channels = 1ULL << channel;

        if (todo == ISO_RES_REALLOC && success)
                goto out;

        if (todo == ISO_RES_ALLOC || todo == ISO_RES_ALLOC_ONCE) {
                e = r->e_alloc;
                r->e_alloc = NULL;
        } else {
                e = r->e_dealloc;
                r->e_dealloc = NULL;
        }
        e->iso_resource.handle    = r->resource.handle;
        e->iso_resource.channel   = channel;
        e->iso_resource.bandwidth = bandwidth;

        queue_event(client, &e->event,
                    &e->iso_resource, sizeof(e->iso_resource), NULL, 0);

        if (free) {
                cancel_delayed_work(&r->work);
                kfree(r->e_alloc);
                kfree(r->e_dealloc);
                kfree(r);
        }
 out:
        client_put(client);
}

static void release_iso_resource(struct client *client,
                                 struct client_resource *resource)
{
        struct iso_resource *r = to_iso_resource(resource);

        guard(spinlock_irq)(&client->lock);

        r->todo = ISO_RES_DEALLOC;
        schedule_iso_resource(r, 0);
}

static int init_iso_resource(struct client *client,
                struct fw_cdev_allocate_iso_resource *request, int todo)
{
        struct iso_resource_event *e1, *e2;
        struct iso_resource *r;
        int ret;

        if ((request->channels == 0 && request->bandwidth == 0) ||
            request->bandwidth > BANDWIDTH_AVAILABLE_INITIAL)
                return -EINVAL;

        r = kmalloc_obj(*r);
        e1 = kmalloc_obj(*e1);
        e2 = kmalloc_obj(*e2);
        if (r == NULL || e1 == NULL || e2 == NULL) {
                ret = -ENOMEM;
                goto fail;
        }

        INIT_DELAYED_WORK(&r->work, iso_resource_work);
        r->client       = client;
        r->todo         = todo;
        r->generation   = -1;
        r->channels     = request->channels;
        r->bandwidth    = request->bandwidth;
        r->e_alloc      = e1;
        r->e_dealloc    = e2;

        e1->iso_resource.closure = request->closure;
        e1->iso_resource.type    = FW_CDEV_EVENT_ISO_RESOURCE_ALLOCATED;
        e2->iso_resource.closure = request->closure;
        e2->iso_resource.type    = FW_CDEV_EVENT_ISO_RESOURCE_DEALLOCATED;

        if (todo == ISO_RES_ALLOC) {
                r->resource.release = release_iso_resource;
                ret = add_client_resource(client, &r->resource, GFP_KERNEL);
                if (ret < 0)
                        goto fail;
        } else {
                r->resource.release = NULL;
                r->resource.handle = -1;
                schedule_iso_resource(r, 0);
        }
        request->handle = r->resource.handle;

        return 0;
 fail:
        kfree(r);
        kfree(e1);
        kfree(e2);

        return ret;
}

static int ioctl_allocate_iso_resource(struct client *client,
                                       union ioctl_arg *arg)
{
        return init_iso_resource(client,
                        &arg->allocate_iso_resource, ISO_RES_ALLOC);
}

static int ioctl_deallocate_iso_resource(struct client *client,
                                         union ioctl_arg *arg)
{
        return release_client_resource(client,
                        arg->deallocate.handle, release_iso_resource, NULL);
}

static int ioctl_allocate_iso_resource_once(struct client *client,
                                            union ioctl_arg *arg)
{
        return init_iso_resource(client,
                        &arg->allocate_iso_resource, ISO_RES_ALLOC_ONCE);
}

static int ioctl_deallocate_iso_resource_once(struct client *client,
                                              union ioctl_arg *arg)
{
        return init_iso_resource(client,
                        &arg->allocate_iso_resource, ISO_RES_DEALLOC_ONCE);
}

/*
 * Returns a speed code:  Maximum speed to or from this device,
 * limited by the device's link speed, the local node's link speed,
 * and all PHY port speeds between the two links.
 */
static int ioctl_get_speed(struct client *client, union ioctl_arg *arg)
{
        return client->device->max_speed;
}

static int ioctl_send_broadcast_request(struct client *client,
                                        union ioctl_arg *arg)
{
        struct fw_cdev_send_request *a = &arg->send_request;

        switch (a->tcode) {
        case TCODE_WRITE_QUADLET_REQUEST:
        case TCODE_WRITE_BLOCK_REQUEST:
                break;
        default:
                return -EINVAL;
        }

        /* Security policy: Only allow accesses to Units Space. */
        if (a->offset < CSR_REGISTER_BASE + CSR_CONFIG_ROM_END)
                return -EACCES;

        return init_request(client, a, LOCAL_BUS | 0x3f, SCODE_100);
}

static int ioctl_send_stream_packet(struct client *client, union ioctl_arg *arg)
{
        struct fw_cdev_send_stream_packet *a = &arg->send_stream_packet;
        struct fw_cdev_send_request request;
        int dest;

        if (a->speed > client->device->card->link_speed ||
            a->length > 1024 << a->speed)
                return -EIO;

        if (a->tag > 3 || a->channel > 63 || a->sy > 15)
                return -EINVAL;

        dest = fw_stream_packet_destination_id(a->tag, a->channel, a->sy);
        request.tcode           = TCODE_STREAM_DATA;
        request.length          = a->length;
        request.closure         = a->closure;
        request.data            = a->data;
        request.generation      = a->generation;

        return init_request(client, &request, dest, a->speed);
}

static void outbound_phy_packet_callback(struct fw_packet *packet,
                                         struct fw_card *card, int status)
{
        struct outbound_phy_packet_event *e =
                container_of(packet, struct outbound_phy_packet_event, p);
        struct client *e_client = e->client;
        u32 rcode;

        trace_async_phy_outbound_complete((uintptr_t)packet, card->index, status, packet->generation,
                                          packet->timestamp);

        switch (status) {
        // expected:
        case ACK_COMPLETE:
                rcode = RCODE_COMPLETE;
                break;
        // should never happen with PHY packets:
        case ACK_PENDING:
                rcode = RCODE_COMPLETE;
                break;
        case ACK_BUSY_X:
        case ACK_BUSY_A:
        case ACK_BUSY_B:
                rcode = RCODE_BUSY;
                break;
        case ACK_DATA_ERROR:
                rcode = RCODE_DATA_ERROR;
                break;
        case ACK_TYPE_ERROR:
                rcode = RCODE_TYPE_ERROR;
                break;
        // stale generation; cancelled; on certain controllers: no ack
        default:
                rcode = status;
                break;
        }

        switch (e->phy_packet.without_tstamp.type) {
        case FW_CDEV_EVENT_PHY_PACKET_SENT:
        {
                struct fw_cdev_event_phy_packet *pp = &e->phy_packet.without_tstamp;

                pp->rcode = rcode;
                pp->data[0] = packet->timestamp;
                queue_event(e->client, &e->event, &e->phy_packet, sizeof(*pp) + pp->length,
                            NULL, 0);
                break;
        }
        case FW_CDEV_EVENT_PHY_PACKET_SENT2:
        {
                struct fw_cdev_event_phy_packet2 *pp = &e->phy_packet.with_tstamp;

                pp->rcode = rcode;
                pp->tstamp = packet->timestamp;
                queue_event(e->client, &e->event, &e->phy_packet, sizeof(*pp) + pp->length,
                            NULL, 0);
                break;
        }
        default:
                WARN_ON(1);
                break;
        }

        client_put(e_client);
}

static int ioctl_send_phy_packet(struct client *client, union ioctl_arg *arg)
{
        struct fw_cdev_send_phy_packet *a = &arg->send_phy_packet;
        struct fw_card *card = client->device->card;
        struct outbound_phy_packet_event *e;

        /* Access policy: Allow this ioctl only on local nodes' device files. */
        if (!client->device->is_local)
                return -ENOSYS;

        e = kzalloc(sizeof(*e) + sizeof(a->data), GFP_KERNEL);
        if (e == NULL)
                return -ENOMEM;

        client_get(client);
        e->client               = client;
        e->p.speed              = SCODE_100;
        e->p.generation         = a->generation;
        async_header_set_tcode(e->p.header, TCODE_LINK_INTERNAL);
        e->p.header[1]          = a->data[0];
        e->p.header[2]          = a->data[1];
        e->p.header_length      = 12;
        e->p.callback           = outbound_phy_packet_callback;

        if (client->version < FW_CDEV_VERSION_EVENT_ASYNC_TSTAMP) {
                struct fw_cdev_event_phy_packet *pp = &e->phy_packet.without_tstamp;

                pp->closure = a->closure;
                pp->type = FW_CDEV_EVENT_PHY_PACKET_SENT;
                if (is_ping_packet(a->data))
                        pp->length = 4;
        } else {
                struct fw_cdev_event_phy_packet2 *pp = &e->phy_packet.with_tstamp;

                pp->closure = a->closure;
                pp->type = FW_CDEV_EVENT_PHY_PACKET_SENT2;
                // Keep the data field so that application can match the response event to the
                // request.
                pp->length = sizeof(a->data);
                memcpy(pp->data, a->data, sizeof(a->data));
        }

        trace_async_phy_outbound_initiate((uintptr_t)&e->p, card->index, e->p.generation,
                                          e->p.header[1], e->p.header[2]);

        card->driver->send_request(card, &e->p);

        return 0;
}

static int ioctl_receive_phy_packets(struct client *client, union ioctl_arg *arg)
{
        struct fw_cdev_receive_phy_packets *a = &arg->receive_phy_packets;

        /* Access policy: Allow this ioctl only on local nodes' device files. */
        if (!client->device->is_local)
                return -ENOSYS;

        // NOTE: This can be without irq when we can guarantee that __fw_send_request() for local
        // destination never runs in any type of IRQ context.
        scoped_guard(spinlock_irq, &phy_receiver_list_lock)
                list_move_tail(&client->phy_receiver_link, &phy_receiver_list);

        client->phy_receiver_closure = a->closure;

        return 0;
}

void fw_cdev_handle_phy_packet(struct fw_card *card, struct fw_packet *p)
{
        struct client *client;

        // NOTE: This can be without irqsave when we can guarantee that __fw_send_request() for local
        // destination never runs in any type of IRQ context.
        guard(spinlock_irqsave)(&phy_receiver_list_lock);

        list_for_each_entry(client, &phy_receiver_list, phy_receiver_link) {
                struct inbound_phy_packet_event *e;

                if (client->device->card != card)
                        continue;

                e = kmalloc(sizeof(*e) + 8, GFP_ATOMIC);
                if (e == NULL)
                        break;

                if (client->version < FW_CDEV_VERSION_EVENT_ASYNC_TSTAMP) {
                        struct fw_cdev_event_phy_packet *pp = &e->phy_packet.without_tstamp;

                        pp->closure = client->phy_receiver_closure;
                        pp->type = FW_CDEV_EVENT_PHY_PACKET_RECEIVED;
                        pp->rcode = RCODE_COMPLETE;
                        pp->length = 8;
                        pp->data[0] = p->header[1];
                        pp->data[1] = p->header[2];
                        queue_event(client, &e->event, &e->phy_packet, sizeof(*pp) + 8, NULL, 0);
                } else {
                        struct fw_cdev_event_phy_packet2 *pp = &e->phy_packet.with_tstamp;

                        pp = &e->phy_packet.with_tstamp;
                        pp->closure = client->phy_receiver_closure;
                        pp->type = FW_CDEV_EVENT_PHY_PACKET_RECEIVED2;
                        pp->rcode = RCODE_COMPLETE;
                        pp->length = 8;
                        pp->tstamp = p->timestamp;
                        pp->data[0] = p->header[1];
                        pp->data[1] = p->header[2];
                        queue_event(client, &e->event, &e->phy_packet, sizeof(*pp) + 8, NULL, 0);
                }
        }
}

static int (* const ioctl_handlers[])(struct client *, union ioctl_arg *) = {
        [0x00] = ioctl_get_info,
        [0x01] = ioctl_send_request,
        [0x02] = ioctl_allocate,
        [0x03] = ioctl_deallocate,
        [0x04] = ioctl_send_response,
        [0x05] = ioctl_initiate_bus_reset,
        [0x06] = ioctl_add_descriptor,
        [0x07] = ioctl_remove_descriptor,
        [0x08] = ioctl_create_iso_context,
        [0x09] = ioctl_queue_iso,
        [0x0a] = ioctl_start_iso,
        [0x0b] = ioctl_stop_iso,
        [0x0c] = ioctl_get_cycle_timer,
        [0x0d] = ioctl_allocate_iso_resource,
        [0x0e] = ioctl_deallocate_iso_resource,
        [0x0f] = ioctl_allocate_iso_resource_once,
        [0x10] = ioctl_deallocate_iso_resource_once,
        [0x11] = ioctl_get_speed,
        [0x12] = ioctl_send_broadcast_request,
        [0x13] = ioctl_send_stream_packet,
        [0x14] = ioctl_get_cycle_timer2,
        [0x15] = ioctl_send_phy_packet,
        [0x16] = ioctl_receive_phy_packets,
        [0x17] = ioctl_set_iso_channels,
        [0x18] = ioctl_flush_iso,
};

static int dispatch_ioctl(struct client *client,
                          unsigned int cmd, void __user *arg)
{
        union ioctl_arg buffer;
        int ret;

        if (fw_device_is_shutdown(client->device))
                return -ENODEV;

        if (_IOC_TYPE(cmd) != '#' ||
            _IOC_NR(cmd) >= ARRAY_SIZE(ioctl_handlers) ||
            _IOC_SIZE(cmd) > sizeof(buffer))
                return -ENOTTY;

        memset(&buffer, 0, sizeof(buffer));

        if (_IOC_DIR(cmd) & _IOC_WRITE)
                if (copy_from_user(&buffer, arg, _IOC_SIZE(cmd)))
                        return -EFAULT;

        ret = ioctl_handlers[_IOC_NR(cmd)](client, &buffer);
        if (ret < 0)
                return ret;

        if (_IOC_DIR(cmd) & _IOC_READ)
                if (copy_to_user(arg, &buffer, _IOC_SIZE(cmd)))
                        return -EFAULT;

        return ret;
}

static long fw_device_op_ioctl(struct file *file,
                               unsigned int cmd, unsigned long arg)
{
        return dispatch_ioctl(file->private_data, cmd, (void __user *)arg);
}

static int fw_device_op_mmap(struct file *file, struct vm_area_struct *vma)
{
        struct client *client = file->private_data;
        unsigned long size;
        int page_count, ret;

        if (fw_device_is_shutdown(client->device))
                return -ENODEV;

        /* FIXME: We could support multiple buffers, but we don't. */
        if (client->buffer.pages != NULL)
                return -EBUSY;

        if (!(vma->vm_flags & VM_SHARED))
                return -EINVAL;

        if (vma->vm_start & ~PAGE_MASK)
                return -EINVAL;

        client->vm_start = vma->vm_start;
        size = vma->vm_end - vma->vm_start;
        page_count = size >> PAGE_SHIFT;
        if (size & ~PAGE_MASK)
                return -EINVAL;

        ret = fw_iso_buffer_alloc(&client->buffer, page_count);
        if (ret < 0)
                return ret;

        scoped_guard(mutex, &client->iso_context_mutex) {
                // The direction of DMA can be determined if the isochronous context is already
                // allocated. If not, the DMA mapping operation is postponed after the allocation.
                if (client->iso_context) {
                        ret = fw_iso_buffer_map_dma(&client->buffer, client->device->card,
                                                    iso_dma_direction(client->iso_context));
                        if (ret < 0)
                                goto fail;
                }
        }

        ret = vm_map_pages_zero(vma, client->buffer.pages,
                                client->buffer.page_count);
        if (ret < 0)
                goto fail;

        return 0;
 fail:
        fw_iso_buffer_destroy(&client->buffer, client->device->card);
        return ret;
}

static bool has_outbound_transactions(struct client *client)
{
        struct client_resource *resource;
        unsigned long index;

        guard(spinlock_irq)(&client->lock);

        xa_for_each(&client->resource_xa, index, resource) {
                if (is_outbound_transaction_resource(resource))
                        return true;
        }

        return false;
}

static int fw_device_op_release(struct inode *inode, struct file *file)
{
        struct client *client = file->private_data;
        struct event *event, *next_event;
        struct client_resource *resource;
        unsigned long index;

        // NOTE: This can be without irq when we can guarantee that __fw_send_request() for local
        // destination never runs in any type of IRQ context.
        scoped_guard(spinlock_irq, &phy_receiver_list_lock)
                list_del(&client->phy_receiver_link);

        scoped_guard(mutex, &client->device->client_list_mutex)
                list_del(&client->link);

        if (client->iso_context)
                fw_iso_context_destroy(client->iso_context);
        mutex_destroy(&client->iso_context_mutex);

        if (client->buffer.pages)
                fw_iso_buffer_destroy(&client->buffer, client->device->card);

        // Freeze client->resource_xa and client->event_list.
        scoped_guard(spinlock_irq, &client->lock)
                client->in_shutdown = true;

        wait_event(client->tx_flush_wait, !has_outbound_transactions(client));

        xa_for_each(&client->resource_xa, index, resource) {
                resource->release(client, resource);
                client_put(client);
        }
        xa_destroy(&client->resource_xa);

        list_for_each_entry_safe(event, next_event, &client->event_list, link)
                kfree(event);

        client_put(client);

        return 0;
}

static __poll_t fw_device_op_poll(struct file *file, poll_table * pt)
{
        struct client *client = file->private_data;
        __poll_t mask = 0;

        poll_wait(file, &client->wait, pt);

        if (fw_device_is_shutdown(client->device))
                mask |= EPOLLHUP | EPOLLERR;
        if (!list_empty(&client->event_list))
                mask |= EPOLLIN | EPOLLRDNORM;

        return mask;
}

const struct file_operations fw_device_ops = {
        .owner          = THIS_MODULE,
        .open           = fw_device_op_open,
        .read           = fw_device_op_read,
        .unlocked_ioctl = fw_device_op_ioctl,
        .mmap           = fw_device_op_mmap,
        .release        = fw_device_op_release,
        .poll           = fw_device_op_poll,
        .compat_ioctl   = compat_ptr_ioctl,
};