Quelle  core-transaction.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Core IEEE1394 transaction logic
 *
 * Copyright (C) 2004-2006 Kristian Hoegsberg <krh@bitplanet.net>
 */

#include <linux/bug.h>
#include <linux/completion.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/firewire.h>
#include <linux/firewire-constants.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/rculist.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/timer.h>
#include <linux/types.h>
#include <linux/workqueue.h>

#include <asm/byteorder.h>

#include "core.h"
#include "packet-header-definitions.h"
#include "phy-packet-definitions.h"
#include <trace/events/firewire.h>

#define HEADER_DESTINATION_IS_BROADCAST(header) \
 ((async_header_get_destination(header) & 0x3f) == 0x3f)

/* returns 0 if the split timeout handler is already running */
static int try_cancel_split_timeout(struct fw_transaction *t)
{
 if (t->is_split_transaction)
  return timer_delete(&t->split_timeout_timer);
 else
  return 1;
}

static int close_transaction(struct fw_transaction *transaction, struct fw_card *card, int rcode,
        u32 response_tstamp)
{
 struct fw_transaction *t = NULL, *iter;

 scoped_guard(spinlock_irqsave, &card->lock) {
  list_for_each_entry(iter, &card->transaction_list, link) {
   if (iter == transaction) {
    if (try_cancel_split_timeout(iter)) {
     list_del_init(&iter->link);
     card->tlabel_mask &= ~(1ULL << iter->tlabel);
     t = iter;
    }
    break;
   }
  }
 }

 if (!t)
  return -ENOENT;

 if (!t->with_tstamp) {
  t->callback.without_tstamp(card, rcode, NULL, 0, t->callback_data);
 } else {
  t->callback.with_tstamp(card, rcode, t->packet.timestamp, response_tstamp, NULL, 0,
     t->callback_data);
 }

 return 0;
}

/*
 * Only valid for transactions that are potentially pending (ie have
 * been sent).
 */
int fw_cancel_transaction(struct fw_card *card,
     struct fw_transaction *transaction)
{
 u32 tstamp;

 /*
 * Cancel the packet transmission if it's still queued.  That
 * will call the packet transmission callback which cancels
 * the transaction.
 */

 if (card->driver->cancel_packet(card, &transaction->packet) == 0)
  return 0;

 /*
 * If the request packet has already been sent, we need to see
 * if the transaction is still pending and remove it in that case.
 */

 if (transaction->packet.ack == 0) {
  // The timestamp is reused since it was just read now.
  tstamp = transaction->packet.timestamp;
 } else {
  u32 curr_cycle_time = 0;

  (void)fw_card_read_cycle_time(card, &curr_cycle_time);
  tstamp = cycle_time_to_ohci_tstamp(curr_cycle_time);
 }

 return close_transaction(transaction, card, RCODE_CANCELLED, tstamp);
}
EXPORT_SYMBOL(fw_cancel_transaction);

static void split_transaction_timeout_callback(struct timer_list *timer)
{
 struct fw_transaction *t = timer_container_of(t, timer, split_timeout_timer);
 struct fw_card *card = t->card;

 scoped_guard(spinlock_irqsave, &card->lock) {
  if (list_empty(&t->link))
   return;
  list_del(&t->link);
  card->tlabel_mask &= ~(1ULL << t->tlabel);
 }

 if (!t->with_tstamp) {
  t->callback.without_tstamp(card, RCODE_CANCELLED, NULL, 0, t->callback_data);
 } else {
  t->callback.with_tstamp(card, RCODE_CANCELLED, t->packet.timestamp,
     t->split_timeout_cycle, NULL, 0, t->callback_data);
 }
}

static void start_split_transaction_timeout(struct fw_transaction *t,
         struct fw_card *card)
{
 guard(spinlock_irqsave)(&card->lock);

 if (list_empty(&t->link) || WARN_ON(t->is_split_transaction))
  return;

 t->is_split_transaction = true;
 mod_timer(&t->split_timeout_timer,
    jiffies + card->split_timeout_jiffies);
}

static u32 compute_split_timeout_timestamp(struct fw_card *card, u32 request_timestamp);

static void transmit_complete_callback(struct fw_packet *packet,
           struct fw_card *card, int status)
{
 struct fw_transaction *t =
     container_of(packet, struct fw_transaction, packet);

 trace_async_request_outbound_complete((uintptr_t)t, card->index, packet->generation,
           packet->speed, status, packet->timestamp);

 switch (status) {
 case ACK_COMPLETE:
  close_transaction(t, card, RCODE_COMPLETE, packet->timestamp);
  break;
 case ACK_PENDING:
 {
  t->split_timeout_cycle =
   compute_split_timeout_timestamp(card, packet->timestamp) & 0xffff;
  start_split_transaction_timeout(t, card);
  break;
 }
 case ACK_BUSY_X:
 case ACK_BUSY_A:
 case ACK_BUSY_B:
  close_transaction(t, card, RCODE_BUSY, packet->timestamp);
  break;
 case ACK_DATA_ERROR:
  close_transaction(t, card, RCODE_DATA_ERROR, packet->timestamp);
  break;
 case ACK_TYPE_ERROR:
  close_transaction(t, card, RCODE_TYPE_ERROR, packet->timestamp);
  break;
 default:
  /*
 * In this case the ack is really a juju specific
 * rcode, so just forward that to the callback.
 */
  close_transaction(t, card, status, packet->timestamp);
  break;
 }
}

static void fw_fill_request(struct fw_packet *packet, int tcode, int tlabel,
  int destination_id, int source_id, int generation, int speed,
  unsigned long long offset, void *payload, size_t length)
{
 int ext_tcode;

 if (tcode == TCODE_STREAM_DATA) {
  // The value of destination_id argument should include tag, channel, and sy fields
  // as isochronous packet header has.
  packet->header[0] = destination_id;
  isoc_header_set_data_length(packet->header, length);
  isoc_header_set_tcode(packet->header, TCODE_STREAM_DATA);
  packet->header_length = 4;
  packet->payload = payload;
  packet->payload_length = length;

  goto common;
 }

 if (tcode > 0x10) {
  ext_tcode = tcode & ~0x10;
  tcode = TCODE_LOCK_REQUEST;
 } else
  ext_tcode = 0;

 async_header_set_retry(packet->header, RETRY_X);
 async_header_set_tlabel(packet->header, tlabel);
 async_header_set_tcode(packet->header, tcode);
 async_header_set_destination(packet->header, destination_id);
 async_header_set_source(packet->header, source_id);
 async_header_set_offset(packet->header, offset);

 switch (tcode) {
 case TCODE_WRITE_QUADLET_REQUEST:
  async_header_set_quadlet_data(packet->header, *(u32 *)payload);
  packet->header_length = 16;
  packet->payload_length = 0;
  break;

 case TCODE_LOCK_REQUEST:
 case TCODE_WRITE_BLOCK_REQUEST:
  async_header_set_data_length(packet->header, length);
  async_header_set_extended_tcode(packet->header, ext_tcode);
  packet->header_length = 16;
  packet->payload = payload;
  packet->payload_length = length;
  break;

 case TCODE_READ_QUADLET_REQUEST:
  packet->header_length = 12;
  packet->payload_length = 0;
  break;

 case TCODE_READ_BLOCK_REQUEST:
  async_header_set_data_length(packet->header, length);
  async_header_set_extended_tcode(packet->header, ext_tcode);
  packet->header_length = 16;
  packet->payload_length = 0;
  break;

 default:
  WARN(1, "wrong tcode %d\n", tcode);
 }
 common:
 packet->speed = speed;
 packet->generation = generation;
 packet->ack = 0;
 packet->payload_mapped = false;
}

static int allocate_tlabel(struct fw_card *card)
{
 int tlabel;

 tlabel = card->current_tlabel;
 while (card->tlabel_mask & (1ULL << tlabel)) {
  tlabel = (tlabel + 1) & 0x3f;
  if (tlabel == card->current_tlabel)
   return -EBUSY;
 }

 card->current_tlabel = (tlabel + 1) & 0x3f;
 card->tlabel_mask |= 1ULL << tlabel;

 return tlabel;
}

/**
 * __fw_send_request() - submit a request packet for transmission to generate callback for response
 *  subaction with or without time stamp.
 * @card: interface to send the request at
 * @t: transaction instance to which the request belongs
 * @tcode: transaction code
 * @destination_id: destination node ID, consisting of bus_ID and phy_ID
 * @generation: bus generation in which request and response are valid
 * @speed: transmission speed
 * @offset: 48bit wide offset into destination's address space
 * @payload: data payload for the request subaction
 * @length: length of the payload, in bytes
 * @callback: union of two functions whether to receive time stamp or not for response
 * subaction.
 * @with_tstamp: Whether to receive time stamp or not for response subaction.
 * @callback_data: data to be passed to the transaction completion callback
 *
 * Submit a request packet into the asynchronous request transmission queue.
 * Can be called from atomic context.  If you prefer a blocking API, use
 * fw_run_transaction() in a context that can sleep.
 *
 * In case of lock requests, specify one of the firewire-core specific %TCODE_
 * constants instead of %TCODE_LOCK_REQUEST in @tcode.
 *
 * Make sure that the value in @destination_id is not older than the one in
 * @generation.  Otherwise the request is in danger to be sent to a wrong node.
 *
 * In case of asynchronous stream packets i.e. %TCODE_STREAM_DATA, the caller
 * needs to synthesize @destination_id with fw_stream_packet_destination_id().
 * It will contain tag, channel, and sy data instead of a node ID then.
 *
 * The payload buffer at @data is going to be DMA-mapped except in case of
 * @length <= 8 or of local (loopback) requests.  Hence make sure that the
 * buffer complies with the restrictions of the streaming DMA mapping API.
 * @payload must not be freed before the @callback is called.
 *
 * In case of request types without payload, @data is NULL and @length is 0.
 *
 * After the transaction is completed successfully or unsuccessfully, the
 * @callback will be called.  Among its parameters is the response code which
 * is either one of the rcodes per IEEE 1394 or, in case of internal errors,
 * the firewire-core specific %RCODE_SEND_ERROR.  The other firewire-core
 * specific rcodes (%RCODE_CANCELLED, %RCODE_BUSY, %RCODE_GENERATION,
 * %RCODE_NO_ACK) denote transaction timeout, busy responder, stale request
 * generation, or missing ACK respectively.
 *
 * Note some timing corner cases:  fw_send_request() may complete much earlier
 * than when the request packet actually hits the wire.  On the other hand,
 * transaction completion and hence execution of @callback may happen even
 * before fw_send_request() returns.
 */
void __fw_send_request(struct fw_card *card, struct fw_transaction *t, int tcode,
  int destination_id, int generation, int speed, unsigned long long offset,
  void *payload, size_t length, union fw_transaction_callback callback,
  bool with_tstamp, void *callback_data)
{
 unsigned long flags;
 int tlabel;

 /*
 * Allocate tlabel from the bitmap and put the transaction on
 * the list while holding the card spinlock.
 */

 spin_lock_irqsave(&card->lock, flags);

 tlabel = allocate_tlabel(card);
 if (tlabel < 0) {
  spin_unlock_irqrestore(&card->lock, flags);
  if (!with_tstamp) {
   callback.without_tstamp(card, RCODE_SEND_ERROR, NULL, 0, callback_data);
  } else {
   // Timestamping on behalf of hardware.
   u32 curr_cycle_time = 0;
   u32 tstamp;

   (void)fw_card_read_cycle_time(card, &curr_cycle_time);
   tstamp = cycle_time_to_ohci_tstamp(curr_cycle_time);

   callback.with_tstamp(card, RCODE_SEND_ERROR, tstamp, tstamp, NULL, 0,
          callback_data);
  }
  return;
 }

 t->node_id = destination_id;
 t->tlabel = tlabel;
 t->card = card;
 t->is_split_transaction = false;
 timer_setup(&t->split_timeout_timer, split_transaction_timeout_callback, 0);
 t->callback = callback;
 t->with_tstamp = with_tstamp;
 t->callback_data = callback_data;

 fw_fill_request(&t->packet, tcode, t->tlabel, destination_id, card->node_id, generation,
   speed, offset, payload, length);
 t->packet.callback = transmit_complete_callback;

 list_add_tail(&t->link, &card->transaction_list);

 spin_unlock_irqrestore(&card->lock, flags);

 trace_async_request_outbound_initiate((uintptr_t)t, card->index, generation, speed,
           t->packet.header, payload,
           tcode_is_read_request(tcode) ? 0 : length / 4);

 card->driver->send_request(card, &t->packet);
}
EXPORT_SYMBOL_GPL(__fw_send_request);

struct transaction_callback_data {
 struct completion done;
 void *payload;
 int rcode;
};

static void transaction_callback(struct fw_card *card, int rcode,
     void *payload, size_t length, void *data)
{
 struct transaction_callback_data *d = data;

 if (rcode == RCODE_COMPLETE)
  memcpy(d->payload, payload, length);
 d->rcode = rcode;
 complete(&d->done);
}

/**
 * fw_run_transaction() - send request and sleep until transaction is completed
 * @card: card interface for this request
 * @tcode: transaction code
 * @destination_id: destination node ID, consisting of bus_ID and phy_ID
 * @generation: bus generation in which request and response are valid
 * @speed: transmission speed
 * @offset: 48bit wide offset into destination's address space
 * @payload: data payload for the request subaction
 * @length: length of the payload, in bytes
 *
 * Returns the RCODE.  See fw_send_request() for parameter documentation.
 * Unlike fw_send_request(), @data points to the payload of the request or/and
 * to the payload of the response.  DMA mapping restrictions apply to outbound
 * request payloads of >= 8 bytes but not to inbound response payloads.
 */
int fw_run_transaction(struct fw_card *card, int tcode, int destination_id,
         int generation, int speed, unsigned long long offset,
         void *payload, size_t length)
{
 struct transaction_callback_data d;
 struct fw_transaction t;

 timer_setup_on_stack(&t.split_timeout_timer, NULL, 0);
 init_completion(&d.done);
 d.payload = payload;
 fw_send_request(card, &t, tcode, destination_id, generation, speed,
   offset, payload, length, transaction_callback, &d);
 wait_for_completion(&d.done);
 timer_destroy_on_stack(&t.split_timeout_timer);

 return d.rcode;
}
EXPORT_SYMBOL(fw_run_transaction);

static DEFINE_MUTEX(phy_config_mutex);
static DECLARE_COMPLETION(phy_config_done);

static void transmit_phy_packet_callback(struct fw_packet *packet,
      struct fw_card *card, int status)
{
 trace_async_phy_outbound_complete((uintptr_t)packet, card->index, packet->generation, status,
       packet->timestamp);
 complete(&phy_config_done);
}

static struct fw_packet phy_config_packet = {
 .header_length = 12,
 .payload_length = 0,
 .speed  = SCODE_100,
 .callback = transmit_phy_packet_callback,
};

void fw_send_phy_config(struct fw_card *card,
   int node_id, int generation, int gap_count)
{
 long timeout = DIV_ROUND_UP(HZ, 10);
 u32 data = 0;

 phy_packet_set_packet_identifier(&data, PHY_PACKET_PACKET_IDENTIFIER_PHY_CONFIG);

 if (node_id != FW_PHY_CONFIG_NO_NODE_ID) {
  phy_packet_phy_config_set_root_id(&data, node_id);
  phy_packet_phy_config_set_force_root_node(&data, true);
 }

 if (gap_count == FW_PHY_CONFIG_CURRENT_GAP_COUNT) {
  gap_count = card->driver->read_phy_reg(card, 1);
  if (gap_count < 0)
   return;

  gap_count &= 63;
  if (gap_count == 63)
   return;
 }
 phy_packet_phy_config_set_gap_count(&data, gap_count);
 phy_packet_phy_config_set_gap_count_optimization(&data, true);

 guard(mutex)(&phy_config_mutex);

 async_header_set_tcode(phy_config_packet.header, TCODE_LINK_INTERNAL);
 phy_config_packet.header[1] = data;
 phy_config_packet.header[2] = ~data;
 phy_config_packet.generation = generation;
 reinit_completion(&phy_config_done);

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

 card->driver->send_request(card, &phy_config_packet);
 wait_for_completion_timeout(&phy_config_done, timeout);
}

static struct fw_address_handler *lookup_overlapping_address_handler(
 struct list_head *list, unsigned long long offset, size_t length)
{
 struct fw_address_handler *handler;

 list_for_each_entry_rcu(handler, list, link) {
  if (handler->offset < offset + length &&
      offset < handler->offset + handler->length)
   return handler;
 }

 return NULL;
}

static bool is_enclosing_handler(struct fw_address_handler *handler,
     unsigned long long offset, size_t length)
{
 return handler->offset <= offset &&
  offset + length <= handler->offset + handler->length;
}

static struct fw_address_handler *lookup_enclosing_address_handler(
 struct list_head *list, unsigned long long offset, size_t length)
{
 struct fw_address_handler *handler;

 list_for_each_entry_rcu(handler, list, link) {
  if (is_enclosing_handler(handler, offset, length))
   return handler;
 }

 return NULL;
}

static DEFINE_SPINLOCK(address_handler_list_lock);
static LIST_HEAD(address_handler_list);

const struct fw_address_region fw_high_memory_region =
 { .start = FW_MAX_PHYSICAL_RANGE, .end = 0xffffe0000000ULL, };
EXPORT_SYMBOL(fw_high_memory_region);

static const struct fw_address_region low_memory_region =
 { .start = 0x000000000000ULL, .end = FW_MAX_PHYSICAL_RANGE, };

#if 0
const struct fw_address_region fw_private_region =
 { .start = 0xffffe0000000ULL, .end = 0xfffff0000000ULL,  };
const struct fw_address_region fw_csr_region =
 { .start = CSR_REGISTER_BASE,
   .end   = CSR_REGISTER_BASE | CSR_CONFIG_ROM_END,  };
const struct fw_address_region fw_unit_space_region =
 { .start = 0xfffff0000900ULL, .end = 0x1000000000000ULL, };
#endif  /*  0  */

static void complete_address_handler(struct kref *kref)
{
 struct fw_address_handler *handler = container_of(kref, struct fw_address_handler, kref);

 complete(&handler->done);
}

static void get_address_handler(struct fw_address_handler *handler)
{
 kref_get(&handler->kref);
}

static int put_address_handler(struct fw_address_handler *handler)
{
 return kref_put(&handler->kref, complete_address_handler);
}

/**
 * fw_core_add_address_handler() - register for incoming requests
 * @handler: callback
 * @region: region in the IEEE 1212 node space address range
 *
 * region->start, ->end, and handler->length have to be quadlet-aligned.
 *
 * When a request is received that falls within the specified address range, the specified callback
 * is invoked.  The parameters passed to the callback give the details of the particular request.
 * The callback is invoked in the workqueue context in most cases. However, if the request is
 * initiated by the local node, the callback is invoked in the initiator's context.
 *
 * To be called in process context.
 * Return value:  0 on success, non-zero otherwise.
 *
 * The start offset of the handler's address region is determined by
 * fw_core_add_address_handler() and is returned in handler->offset.
 *
 * Address allocations are exclusive, except for the FCP registers.
 */
int fw_core_add_address_handler(struct fw_address_handler *handler,
    const struct fw_address_region *region)
{
 struct fw_address_handler *other;
 int ret = -EBUSY;

 if (region->start & 0xffff000000000003ULL ||
     region->start >= region->end ||
     region->end   > 0x0001000000000000ULL ||
     handler->length & 3 ||
     handler->length == 0)
  return -EINVAL;

 guard(spinlock)(&address_handler_list_lock);

 handler->offset = region->start;
 while (handler->offset + handler->length <= region->end) {
  if (is_in_fcp_region(handler->offset, handler->length))
   other = NULL;
  else
   other = lookup_overlapping_address_handler
     (&address_handler_list,
      handler->offset, handler->length);
  if (other != NULL) {
   handler->offset += other->length;
  } else {
   init_completion(&handler->done);
   kref_init(&handler->kref);
   list_add_tail_rcu(&handler->link, &address_handler_list);
   ret = 0;
   break;
  }
 }

 return ret;
}
EXPORT_SYMBOL(fw_core_add_address_handler);

/**
 * fw_core_remove_address_handler() - unregister an address handler
 * @handler: callback
 *
 * To be called in process context.
 *
 * When fw_core_remove_address_handler() returns, @handler->callback() is
 * guaranteed to not run on any CPU anymore.
 */
void fw_core_remove_address_handler(struct fw_address_handler *handler)
{
 scoped_guard(spinlock, &address_handler_list_lock)
  list_del_rcu(&handler->link);

 synchronize_rcu();

 if (!put_address_handler(handler))
  wait_for_completion(&handler->done);
}
EXPORT_SYMBOL(fw_core_remove_address_handler);

struct fw_request {
 struct kref kref;
 struct fw_packet response;
 u32 request_header[ASYNC_HEADER_QUADLET_COUNT];
 int ack;
 u32 timestamp;
 u32 length;
 u32 data[];
};

void fw_request_get(struct fw_request *request)
{
 kref_get(&request->kref);
}

static void release_request(struct kref *kref)
{
 struct fw_request *request = container_of(kref, struct fw_request, kref);

 kfree(request);
}

void fw_request_put(struct fw_request *request)
{
 kref_put(&request->kref, release_request);
}

static void free_response_callback(struct fw_packet *packet,
       struct fw_card *card, int status)
{
 struct fw_request *request = container_of(packet, struct fw_request, response);

 trace_async_response_outbound_complete((uintptr_t)request, card->index, packet->generation,
            packet->speed, status, packet->timestamp);

 // Decrease the reference count since not at in-flight.
 fw_request_put(request);

 // Decrease the reference count to release the object.
 fw_request_put(request);
}

int fw_get_response_length(struct fw_request *r)
{
 int tcode, ext_tcode, data_length;

 tcode = async_header_get_tcode(r->request_header);

 switch (tcode) {
 case TCODE_WRITE_QUADLET_REQUEST:
 case TCODE_WRITE_BLOCK_REQUEST:
  return 0;

 case TCODE_READ_QUADLET_REQUEST:
  return 4;

 case TCODE_READ_BLOCK_REQUEST:
  data_length = async_header_get_data_length(r->request_header);
  return data_length;

 case TCODE_LOCK_REQUEST:
  ext_tcode = async_header_get_extended_tcode(r->request_header);
  data_length = async_header_get_data_length(r->request_header);
  switch (ext_tcode) {
  case EXTCODE_FETCH_ADD:
  case EXTCODE_LITTLE_ADD:
   return data_length;
  default:
   return data_length / 2;
  }

 default:
  WARN(1, "wrong tcode %d\n", tcode);
  return 0;
 }
}

void fw_fill_response(struct fw_packet *response, u32 *request_header,
        int rcode, void *payload, size_t length)
{
 int tcode, tlabel, extended_tcode, source, destination;

 tcode = async_header_get_tcode(request_header);
 tlabel = async_header_get_tlabel(request_header);
 source = async_header_get_destination(request_header); // Exchange.
 destination = async_header_get_source(request_header); // Exchange.
 extended_tcode = async_header_get_extended_tcode(request_header);

 async_header_set_retry(response->header, RETRY_1);
 async_header_set_tlabel(response->header, tlabel);
 async_header_set_destination(response->header, destination);
 async_header_set_source(response->header, source);
 async_header_set_rcode(response->header, rcode);
 response->header[2] = 0; // The field is reserved.

 switch (tcode) {
 case TCODE_WRITE_QUADLET_REQUEST:
 case TCODE_WRITE_BLOCK_REQUEST:
  async_header_set_tcode(response->header, TCODE_WRITE_RESPONSE);
  response->header_length = 12;
  response->payload_length = 0;
  break;

 case TCODE_READ_QUADLET_REQUEST:
  async_header_set_tcode(response->header, TCODE_READ_QUADLET_RESPONSE);
  if (payload != NULL)
   async_header_set_quadlet_data(response->header, *(u32 *)payload);
  else
   async_header_set_quadlet_data(response->header, 0);
  response->header_length = 16;
  response->payload_length = 0;
  break;

 case TCODE_READ_BLOCK_REQUEST:
 case TCODE_LOCK_REQUEST:
  async_header_set_tcode(response->header, tcode + 2);
  async_header_set_data_length(response->header, length);
  async_header_set_extended_tcode(response->header, extended_tcode);
  response->header_length = 16;
  response->payload = payload;
  response->payload_length = length;
  break;

 default:
  WARN(1, "wrong tcode %d\n", tcode);
 }

 response->payload_mapped = false;
}
EXPORT_SYMBOL(fw_fill_response);

static u32 compute_split_timeout_timestamp(struct fw_card *card,
        u32 request_timestamp)
{
 unsigned int cycles;
 u32 timestamp;

 cycles = card->split_timeout_cycles;
 cycles += request_timestamp & 0x1fff;

 timestamp = request_timestamp & ~0x1fff;
 timestamp += (cycles / 8000) << 13;
 timestamp |= cycles % 8000;

 return timestamp;
}

static struct fw_request *allocate_request(struct fw_card *card,
        struct fw_packet *p)
{
 struct fw_request *request;
 u32 *data, length;
 int request_tcode;

 request_tcode = async_header_get_tcode(p->header);
 switch (request_tcode) {
 case TCODE_WRITE_QUADLET_REQUEST:
  data = &p->header[3];
  length = 4;
  break;

 case TCODE_WRITE_BLOCK_REQUEST:
 case TCODE_LOCK_REQUEST:
  data = p->payload;
  length = async_header_get_data_length(p->header);
  break;

 case TCODE_READ_QUADLET_REQUEST:
  data = NULL;
  length = 4;
  break;

 case TCODE_READ_BLOCK_REQUEST:
  data = NULL;
  length = async_header_get_data_length(p->header);
  break;

 default:
  fw_notice(card, "ERROR - corrupt request received - %08x %08x %08x\n",
    p->header[0], p->header[1], p->header[2]);
  return NULL;
 }

 request = kmalloc(sizeof(*request) + length, GFP_ATOMIC);
 if (request == NULL)
  return NULL;
 kref_init(&request->kref);

 request->response.speed = p->speed;
 request->response.timestamp =
   compute_split_timeout_timestamp(card, p->timestamp);
 request->response.generation = p->generation;
 request->response.ack = 0;
 request->response.callback = free_response_callback;
 request->ack = p->ack;
 request->timestamp = p->timestamp;
 request->length = length;
 if (data)
  memcpy(request->data, data, length);

 memcpy(request->request_header, p->header, sizeof(p->header));

 return request;
}

/**
 * fw_send_response: - send response packet for asynchronous transaction.
 * @card: interface to send the response at.
 * @request: firewire request data for the transaction.
 * @rcode: response code to send.
 *
 * Submit a response packet into the asynchronous response transmission queue. The @request
 * is going to be released when the transmission successfully finishes later.
 */
void fw_send_response(struct fw_card *card,
        struct fw_request *request, int rcode)
{
 u32 *data = NULL;
 unsigned int data_length = 0;

 /* unified transaction or broadcast transaction: don't respond */
 if (request->ack != ACK_PENDING ||
     HEADER_DESTINATION_IS_BROADCAST(request->request_header)) {
  fw_request_put(request);
  return;
 }

 if (rcode == RCODE_COMPLETE) {
  data = request->data;
  data_length = fw_get_response_length(request);
 }

 fw_fill_response(&request->response, request->request_header, rcode, data, data_length);

 // Increase the reference count so that the object is kept during in-flight.
 fw_request_get(request);

 trace_async_response_outbound_initiate((uintptr_t)request, card->index,
            request->response.generation, request->response.speed,
            request->response.header, data,
            data ? data_length / 4 : 0);

 card->driver->send_response(card, &request->response);
}
EXPORT_SYMBOL(fw_send_response);

/**
 * fw_get_request_speed() - returns speed at which the @request was received
 * @request: firewire request data
 */
int fw_get_request_speed(struct fw_request *request)
{
 return request->response.speed;
}
EXPORT_SYMBOL(fw_get_request_speed);

/**
 * fw_request_get_timestamp: Get timestamp of the request.
 * @request: The opaque pointer to request structure.
 *
 * Get timestamp when 1394 OHCI controller receives the asynchronous request subaction. The
 * timestamp consists of the low order 3 bits of second field and the full 13 bits of count
 * field of isochronous cycle time register.
 *
 * Returns: timestamp of the request.
 */
u32 fw_request_get_timestamp(const struct fw_request *request)
{
 return request->timestamp;
}
EXPORT_SYMBOL_GPL(fw_request_get_timestamp);

static void handle_exclusive_region_request(struct fw_card *card,
         struct fw_packet *p,
         struct fw_request *request,
         unsigned long long offset)
{
 struct fw_address_handler *handler;
 int tcode, destination, source;

 destination = async_header_get_destination(p->header);
 source = async_header_get_source(p->header);
 tcode = async_header_get_tcode(p->header);
 if (tcode == TCODE_LOCK_REQUEST)
  tcode = 0x10 + async_header_get_extended_tcode(p->header);

 scoped_guard(rcu) {
  handler = lookup_enclosing_address_handler(&address_handler_list, offset,
          request->length);
  if (handler)
   get_address_handler(handler);
 }

 if (!handler) {
  fw_send_response(card, request, RCODE_ADDRESS_ERROR);
  return;
 }

 // Outside the RCU read-side critical section. Without spinlock. With reference count.
 handler->address_callback(card, request, tcode, destination, source, p->generation, offset,
      request->data, request->length, handler->callback_data);
 put_address_handler(handler);
}

// To use kmalloc allocator efficiently, this should be power of two.
#define BUFFER_ON_KERNEL_STACK_SIZE 4

static void handle_fcp_region_request(struct fw_card *card,
          struct fw_packet *p,
          struct fw_request *request,
          unsigned long long offset)
{
 struct fw_address_handler *buffer_on_kernel_stack[BUFFER_ON_KERNEL_STACK_SIZE];
 struct fw_address_handler *handler, **handlers;
 int tcode, destination, source, i, count, buffer_size;

 if ((offset != (CSR_REGISTER_BASE | CSR_FCP_COMMAND) &&
      offset != (CSR_REGISTER_BASE | CSR_FCP_RESPONSE)) ||
     request->length > 0x200) {
  fw_send_response(card, request, RCODE_ADDRESS_ERROR);

  return;
 }

 tcode = async_header_get_tcode(p->header);
 destination = async_header_get_destination(p->header);
 source = async_header_get_source(p->header);

 if (tcode != TCODE_WRITE_QUADLET_REQUEST &&
     tcode != TCODE_WRITE_BLOCK_REQUEST) {
  fw_send_response(card, request, RCODE_TYPE_ERROR);

  return;
 }

 count = 0;
 handlers = buffer_on_kernel_stack;
 buffer_size = ARRAY_SIZE(buffer_on_kernel_stack);
 scoped_guard(rcu) {
  list_for_each_entry_rcu(handler, &address_handler_list, link) {
   if (is_enclosing_handler(handler, offset, request->length)) {
    if (count >= buffer_size) {
     int next_size = buffer_size * 2;
     struct fw_address_handler **buffer_on_kernel_heap;

     if (handlers == buffer_on_kernel_stack)
      buffer_on_kernel_heap = NULL;
     else
      buffer_on_kernel_heap = handlers;

     buffer_on_kernel_heap =
      krealloc_array(buffer_on_kernel_heap, next_size,
       sizeof(*buffer_on_kernel_heap), GFP_ATOMIC);
     // FCP is used for purposes unrelated to significant system
     // resources (e.g. storage or networking), so allocation
     // failures are not considered so critical.
     if (!buffer_on_kernel_heap)
      break;

     if (handlers == buffer_on_kernel_stack) {
      memcpy(buffer_on_kernel_heap, buffer_on_kernel_stack,
             sizeof(buffer_on_kernel_stack));
     }

     handlers = buffer_on_kernel_heap;
     buffer_size = next_size;
    }
    get_address_handler(handler);
    handlers[count++] = handler;
   }
  }
 }

 for (i = 0; i < count; ++i) {
  handler = handlers[i];
  handler->address_callback(card, request, tcode, destination, source,
       p->generation, offset, request->data,
       request->length, handler->callback_data);
  put_address_handler(handler);
 }

 if (handlers != buffer_on_kernel_stack)
  kfree(handlers);

 fw_send_response(card, request, RCODE_COMPLETE);
}

void fw_core_handle_request(struct fw_card *card, struct fw_packet *p)
{
 struct fw_request *request;
 unsigned long long offset;
 unsigned int tcode;

 if (p->ack != ACK_PENDING && p->ack != ACK_COMPLETE)
  return;

 tcode = async_header_get_tcode(p->header);
 if (tcode_is_link_internal(tcode)) {
  trace_async_phy_inbound((uintptr_t)p, card->index, p->generation, p->ack, p->timestamp,
      p->header[1], p->header[2]);
  fw_cdev_handle_phy_packet(card, p);
  return;
 }

 request = allocate_request(card, p);
 if (request == NULL) {
  /* FIXME: send statically allocated busy packet. */
  return;
 }

 trace_async_request_inbound((uintptr_t)request, card->index, p->generation, p->speed,
        p->ack, p->timestamp, p->header, request->data,
        tcode_is_read_request(tcode) ? 0 : request->length / 4);

 offset = async_header_get_offset(p->header);

 if (!is_in_fcp_region(offset, request->length))
  handle_exclusive_region_request(card, p, request, offset);
 else
  handle_fcp_region_request(card, p, request, offset);

}
EXPORT_SYMBOL(fw_core_handle_request);

void fw_core_handle_response(struct fw_card *card, struct fw_packet *p)
{
 struct fw_transaction *t = NULL, *iter;
 u32 *data;
 size_t data_length;
 int tcode, tlabel, source, rcode;

 tcode = async_header_get_tcode(p->header);
 tlabel = async_header_get_tlabel(p->header);
 source = async_header_get_source(p->header);
 rcode = async_header_get_rcode(p->header);

 // FIXME: sanity check packet, is length correct, does tcodes
 // and addresses match to the transaction request queried later.
 //
 // For the tracepoints event, let us decode the header here against the concern.

 switch (tcode) {
 case TCODE_READ_QUADLET_RESPONSE:
  data = (u32 *) &p->header[3];
  data_length = 4;
  break;

 case TCODE_WRITE_RESPONSE:
  data = NULL;
  data_length = 0;
  break;

 case TCODE_READ_BLOCK_RESPONSE:
 case TCODE_LOCK_RESPONSE:
  data = p->payload;
  data_length = async_header_get_data_length(p->header);
  break;

 default:
  /* Should never happen, this is just to shut up gcc. */
  data = NULL;
  data_length = 0;
  break;
 }

 scoped_guard(spinlock_irqsave, &card->lock) {
  list_for_each_entry(iter, &card->transaction_list, link) {
   if (iter->node_id == source && iter->tlabel == tlabel) {
    if (try_cancel_split_timeout(iter)) {
     list_del_init(&iter->link);
     card->tlabel_mask &= ~(1ULL << iter->tlabel);
     t = iter;
    }
    break;
   }
  }
 }

 trace_async_response_inbound((uintptr_t)t, card->index, p->generation, p->speed, p->ack,
         p->timestamp, p->header, data, data_length / 4);

 if (!t) {
  fw_notice(card, "unsolicited response (source %x, tlabel %x)\n",
     source, tlabel);
  return;
 }

 /*
 * The response handler may be executed while the request handler
 * is still pending.  Cancel the request handler.
 */
 card->driver->cancel_packet(card, &t->packet);

 if (!t->with_tstamp) {
  t->callback.without_tstamp(card, rcode, data, data_length, t->callback_data);
 } else {
  t->callback.with_tstamp(card, rcode, t->packet.timestamp, p->timestamp, data,
     data_length, t->callback_data);
 }
}
EXPORT_SYMBOL(fw_core_handle_response);

/**
 * fw_rcode_string - convert a firewire result code to an error description
 * @rcode: the result code
 */
const char *fw_rcode_string(int rcode)
{
 static const char *const names[] = {
  [RCODE_COMPLETE]       = "no error",
  [RCODE_CONFLICT_ERROR] = "conflict error",
  [RCODE_DATA_ERROR]     = "data error",
  [RCODE_TYPE_ERROR]     = "type error",
  [RCODE_ADDRESS_ERROR]  = "address error",
  [RCODE_SEND_ERROR]     = "send error",
  [RCODE_CANCELLED]      = "timeout",
  [RCODE_BUSY]           = "busy",
  [RCODE_GENERATION]     = "bus reset",
  [RCODE_NO_ACK]         = "no ack",
 };

 if ((unsigned int)rcode < ARRAY_SIZE(names) && names[rcode])
  return names[rcode];
 else
  return "unknown";
}
EXPORT_SYMBOL(fw_rcode_string);

static const struct fw_address_region topology_map_region =
 { .start = CSR_REGISTER_BASE | CSR_TOPOLOGY_MAP,
   .end   = CSR_REGISTER_BASE | CSR_TOPOLOGY_MAP_END, };

static void handle_topology_map(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)
{
 int start;

 if (!tcode_is_read_request(tcode)) {
  fw_send_response(card, request, RCODE_TYPE_ERROR);
  return;
 }

 if ((offset & 3) > 0 || (length & 3) > 0) {
  fw_send_response(card, request, RCODE_ADDRESS_ERROR);
  return;
 }

 start = (offset - topology_map_region.start) / 4;
 memcpy(payload, &card->topology_map[start], length);

 fw_send_response(card, request, RCODE_COMPLETE);
}

static struct fw_address_handler topology_map = {
 .length   = 0x400,
 .address_callback = handle_topology_map,
};

static const struct fw_address_region registers_region =
 { .start = CSR_REGISTER_BASE,
   .end   = CSR_REGISTER_BASE | CSR_CONFIG_ROM, };

static void update_split_timeout(struct fw_card *card)
{
 unsigned int cycles;

 cycles = card->split_timeout_hi * 8000 + (card->split_timeout_lo >> 19);

 /* minimum per IEEE 1394, maximum which doesn't overflow OHCI */
 cycles = clamp(cycles, 800u, 3u * 8000u);

 card->split_timeout_cycles = cycles;
 card->split_timeout_jiffies = DIV_ROUND_UP(cycles * HZ, 8000);
}

static void handle_registers(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)
{
 int reg = offset & ~CSR_REGISTER_BASE;
 __be32 *data = payload;
 int rcode = RCODE_COMPLETE;

 switch (reg) {
 case CSR_PRIORITY_BUDGET:
  if (!card->priority_budget_implemented) {
   rcode = RCODE_ADDRESS_ERROR;
   break;
  }
  fallthrough;

 case CSR_NODE_IDS:
  /*
 * per IEEE 1394-2008 8.3.22.3, not IEEE 1394.1-2004 3.2.8
 * and 9.6, but interoperable with IEEE 1394.1-2004 bridges
 */
  fallthrough;

 case CSR_STATE_CLEAR:
 case CSR_STATE_SET:
 case CSR_CYCLE_TIME:
 case CSR_BUS_TIME:
 case CSR_BUSY_TIMEOUT:
  if (tcode == TCODE_READ_QUADLET_REQUEST)
   *data = cpu_to_be32(card->driver->read_csr(card, reg));
  else if (tcode == TCODE_WRITE_QUADLET_REQUEST)
   card->driver->write_csr(card, reg, be32_to_cpu(*data));
  else
   rcode = RCODE_TYPE_ERROR;
  break;

 case CSR_RESET_START:
  if (tcode == TCODE_WRITE_QUADLET_REQUEST)
   card->driver->write_csr(card, CSR_STATE_CLEAR,
      CSR_STATE_BIT_ABDICATE);
  else
   rcode = RCODE_TYPE_ERROR;
  break;

 case CSR_SPLIT_TIMEOUT_HI:
  if (tcode == TCODE_READ_QUADLET_REQUEST) {
   *data = cpu_to_be32(card->split_timeout_hi);
  } else if (tcode == TCODE_WRITE_QUADLET_REQUEST) {
   guard(spinlock_irqsave)(&card->lock);

   card->split_timeout_hi = be32_to_cpu(*data) & 7;
   update_split_timeout(card);
  } else {
   rcode = RCODE_TYPE_ERROR;
  }
  break;

 case CSR_SPLIT_TIMEOUT_LO:
  if (tcode == TCODE_READ_QUADLET_REQUEST) {
   *data = cpu_to_be32(card->split_timeout_lo);
  } else if (tcode == TCODE_WRITE_QUADLET_REQUEST) {
   guard(spinlock_irqsave)(&card->lock);

   card->split_timeout_lo = be32_to_cpu(*data) & 0xfff80000;
   update_split_timeout(card);
  } else {
   rcode = RCODE_TYPE_ERROR;
  }
  break;

 case CSR_MAINT_UTILITY:
  if (tcode == TCODE_READ_QUADLET_REQUEST)
   *data = card->maint_utility_register;
  else if (tcode == TCODE_WRITE_QUADLET_REQUEST)
   card->maint_utility_register = *data;
  else
   rcode = RCODE_TYPE_ERROR;
  break;

 case CSR_BROADCAST_CHANNEL:
  if (tcode == TCODE_READ_QUADLET_REQUEST)
   *data = cpu_to_be32(card->broadcast_channel);
  else if (tcode == TCODE_WRITE_QUADLET_REQUEST)
   card->broadcast_channel =
       (be32_to_cpu(*data) & BROADCAST_CHANNEL_VALID) |
       BROADCAST_CHANNEL_INITIAL;
  else
   rcode = RCODE_TYPE_ERROR;
  break;

 case CSR_BUS_MANAGER_ID:
 case CSR_BANDWIDTH_AVAILABLE:
 case CSR_CHANNELS_AVAILABLE_HI:
 case CSR_CHANNELS_AVAILABLE_LO:
  /*
 * FIXME: these are handled by the OHCI hardware and
 * the stack never sees these request. If we add
 * support for a new type of controller that doesn't
 * handle this in hardware we need to deal with these
 * transactions.
 */
  BUG();
  break;

 default:
  rcode = RCODE_ADDRESS_ERROR;
  break;
 }

 fw_send_response(card, request, rcode);
}

static struct fw_address_handler registers = {
 .length   = 0x400,
 .address_callback = handle_registers,
};

static void handle_low_memory(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)
{
 /*
 * This catches requests not handled by the physical DMA unit,
 * i.e., wrong transaction types or unauthorized source nodes.
 */
 fw_send_response(card, request, RCODE_TYPE_ERROR);
}

static struct fw_address_handler low_memory = {
 .length   = FW_MAX_PHYSICAL_RANGE,
 .address_callback = handle_low_memory,
};

MODULE_AUTHOR("Kristian Hoegsberg ");
MODULE_DESCRIPTION("Core IEEE1394 transaction logic");
MODULE_LICENSE("GPL");

static const u32 vendor_textual_descriptor[] = {
 /* textual descriptor leaf () */
 0x00060000,
 0x00000000,
 0x00000000,
 0x4c696e75,  /* L i n u */
 0x78204669,  /* x   F i */
 0x72657769,  /* r e w i */
 0x72650000,  /* r e     */
};

static const u32 model_textual_descriptor[] = {
 /* model descriptor leaf () */
 0x00030000,
 0x00000000,
 0x00000000,
 0x4a756a75,  /* J u j u */
};

static struct fw_descriptor vendor_id_descriptor = {
 .length = ARRAY_SIZE(vendor_textual_descriptor),
 .immediate = 0x03001f11,
 .key = 0x81000000,
 .data = vendor_textual_descriptor,
};

static struct fw_descriptor model_id_descriptor = {
 .length = ARRAY_SIZE(model_textual_descriptor),
 .immediate = 0x17023901,
 .key = 0x81000000,
 .data = model_textual_descriptor,
};

static int __init fw_core_init(void)
{
 int ret;

 fw_workqueue = alloc_workqueue("firewire", WQ_MEM_RECLAIM, 0);
 if (!fw_workqueue)
  return -ENOMEM;

 ret = bus_register(&fw_bus_type);
 if (ret < 0) {
  destroy_workqueue(fw_workqueue);
  return ret;
 }

 fw_cdev_major = register_chrdev(0, "firewire", &fw_device_ops);
 if (fw_cdev_major < 0) {
  bus_unregister(&fw_bus_type);
  destroy_workqueue(fw_workqueue);
  return fw_cdev_major;
 }

 fw_core_add_address_handler(&topology_map, &topology_map_region);
 fw_core_add_address_handler(®isters, ®isters_region);
 fw_core_add_address_handler(&low_memory, &low_memory_region);
 fw_core_add_descriptor(&vendor_id_descriptor);
 fw_core_add_descriptor(&model_id_descriptor);

 return 0;
}

static void __exit fw_core_cleanup(void)
{
 unregister_chrdev(fw_cdev_major, "firewire");
 bus_unregister(&fw_bus_type);
 destroy_workqueue(fw_workqueue);
 xa_destroy(&fw_device_xa);
}

module_init(fw_core_init);
module_exit(fw_core_cleanup);