proc: simplify locking in remove_proc_entry()

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / firewire / fw-transaction.c

/*
 * Core IEEE1394 transaction logic
 *
 * Copyright (C) 2004-2006 Kristian Hoegsberg <krh@bitplanet.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include <linux/completion.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/pci.h>
#include <linux/delay.h>
#include <linux/poll.h>
#include <linux/list.h>
#include <linux/kthread.h>
#include <asm/uaccess.h>

#include "fw-transaction.h"
#include "fw-topology.h"
#include "fw-device.h"

#define HEADER_PRI(pri)                 ((pri) << 0)
#define HEADER_TCODE(tcode)             ((tcode) << 4)
#define HEADER_RETRY(retry)             ((retry) << 8)
#define HEADER_TLABEL(tlabel)           ((tlabel) << 10)
#define HEADER_DESTINATION(destination) ((destination) << 16)
#define HEADER_SOURCE(source)           ((source) << 16)
#define HEADER_RCODE(rcode)             ((rcode) << 12)
#define HEADER_OFFSET_HIGH(offset_high) ((offset_high) << 0)
#define HEADER_DATA_LENGTH(length)      ((length) << 16)
#define HEADER_EXTENDED_TCODE(tcode)    ((tcode) << 0)

#define HEADER_GET_TCODE(q)             (((q) >> 4) & 0x0f)
#define HEADER_GET_TLABEL(q)            (((q) >> 10) & 0x3f)
#define HEADER_GET_RCODE(q)             (((q) >> 12) & 0x0f)
#define HEADER_GET_DESTINATION(q)       (((q) >> 16) & 0xffff)
#define HEADER_GET_SOURCE(q)            (((q) >> 16) & 0xffff)
#define HEADER_GET_OFFSET_HIGH(q)       (((q) >> 0) & 0xffff)
#define HEADER_GET_DATA_LENGTH(q)       (((q) >> 16) & 0xffff)
#define HEADER_GET_EXTENDED_TCODE(q)    (((q) >> 0) & 0xffff)

#define PHY_CONFIG_GAP_COUNT(gap_count) (((gap_count) << 16) | (1 << 22))
#define PHY_CONFIG_ROOT_ID(node_id)     ((((node_id) & 0x3f) << 24) | (1 << 23))
#define PHY_IDENTIFIER(id)              ((id) << 30)

static int
close_transaction(struct fw_transaction *transaction,
                  struct fw_card *card, int rcode,
                  u32 *payload, size_t length)
{
        struct fw_transaction *t;
        unsigned long flags;

        spin_lock_irqsave(&card->lock, flags);
        list_for_each_entry(t, &card->transaction_list, link) {
                if (t == transaction) {
                        list_del(&t->link);
                        card->tlabel_mask &= ~(1 << t->tlabel);
                        break;
                }
        }
        spin_unlock_irqrestore(&card->lock, flags);

        if (&t->link != &card->transaction_list) {
                t->callback(card, rcode, payload, length, t->callback_data);
                return 0;
        }

        return -ENOENT;
}

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

        return close_transaction(transaction, card, RCODE_CANCELLED, NULL, 0);
}
EXPORT_SYMBOL(fw_cancel_transaction);

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);

        switch (status) {
        case ACK_COMPLETE:
                close_transaction(t, card, RCODE_COMPLETE, NULL, 0);
                break;
        case ACK_PENDING:
                t->timestamp = packet->timestamp;
                break;
        case ACK_BUSY_X:
        case ACK_BUSY_A:
        case ACK_BUSY_B:
                close_transaction(t, card, RCODE_BUSY, NULL, 0);
                break;
        case ACK_DATA_ERROR:
                close_transaction(t, card, RCODE_DATA_ERROR, NULL, 0);
                break;
        case ACK_TYPE_ERROR:
                close_transaction(t, card, RCODE_TYPE_ERROR, NULL, 0);
                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, NULL, 0);
                break;
        }
}

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

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

        packet->header[0] =
                HEADER_RETRY(RETRY_X) |
                HEADER_TLABEL(tlabel) |
                HEADER_TCODE(tcode) |
                HEADER_DESTINATION(node_id);
        packet->header[1] =
                HEADER_OFFSET_HIGH(offset >> 32) | HEADER_SOURCE(source_id);
        packet->header[2] =
                offset;

        switch (tcode) {
        case TCODE_WRITE_QUADLET_REQUEST:
                packet->header[3] = *(u32 *)payload;
                packet->header_length = 16;
                packet->payload_length = 0;
                break;

        case TCODE_LOCK_REQUEST:
        case TCODE_WRITE_BLOCK_REQUEST:
                packet->header[3] =
                        HEADER_DATA_LENGTH(length) |
                        HEADER_EXTENDED_TCODE(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:
                packet->header[3] =
                        HEADER_DATA_LENGTH(length) |
                        HEADER_EXTENDED_TCODE(ext_tcode);
                packet->header_length = 16;
                packet->payload_length = 0;
                break;
        }

        packet->speed = speed;
        packet->generation = generation;
        packet->ack = 0;
}

/**
 * This function provides low-level access to the IEEE1394 transaction
 * logic.  Most C programs would use either fw_read(), fw_write() or
 * fw_lock() instead - those function are convenience wrappers for
 * this function.  The fw_send_request() function is primarily
 * provided as a flexible, one-stop entry point for languages bindings
 * and protocol bindings.
 *
 * FIXME: Document this function further, in particular the possible
 * values for rcode in the callback.  In short, we map ACK_COMPLETE to
 * RCODE_COMPLETE, internal errors set errno and set rcode to
 * RCODE_SEND_ERROR (which is out of range for standard ieee1394
 * rcodes).  All other rcodes are forwarded unchanged.  For all
 * errors, payload is NULL, length is 0.
 *
 * Can not expect the callback to be called before the function
 * returns, though this does happen in some cases (ACK_COMPLETE and
 * errors).
 *
 * The payload is only used for write requests and must not be freed
 * until the callback has been called.
 *
 * @param card the card from which to send the request
 * @param tcode the tcode for this transaction.  Do not use
 *   TCODE_LOCK_REQUEST directly, instead use TCODE_LOCK_MASK_SWAP
 *   etc. to specify tcode and ext_tcode.
 * @param node_id the destination node ID (bus ID and PHY ID concatenated)
 * @param generation the generation for which node_id is valid
 * @param speed the speed to use for sending the request
 * @param offset the 48 bit offset on the destination node
 * @param payload the data payload for the request subaction
 * @param length the length in bytes of the data to read
 * @param callback function to be called when the transaction is completed
 * @param callback_data pointer to arbitrary data, which will be
 *   passed to the callback
 */
void
fw_send_request(struct fw_card *card, struct fw_transaction *t,
                int tcode, int node_id, int generation, int speed,
                unsigned long long offset,
                void *payload, size_t length,
                fw_transaction_callback_t callback, void *callback_data)
{
        unsigned long flags;
        int tlabel, source;

        /*
         * Bump the flush timer up 100ms first of all so we
         * don't race with a flush timer callback.
         */

        mod_timer(&card->flush_timer, jiffies + DIV_ROUND_UP(HZ, 10));

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

        spin_lock_irqsave(&card->lock, flags);

        source = card->node_id;
        tlabel = card->current_tlabel;
        if (card->tlabel_mask & (1 << tlabel)) {
                spin_unlock_irqrestore(&card->lock, flags);
                callback(card, RCODE_SEND_ERROR, NULL, 0, callback_data);
                return;
        }

        card->current_tlabel = (card->current_tlabel + 1) & 0x1f;
        card->tlabel_mask |= (1 << tlabel);

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

        spin_unlock_irqrestore(&card->lock, flags);

        /* Initialize rest of transaction, fill out packet and send it. */
        t->node_id = node_id;
        t->tlabel = tlabel;
        t->callback = callback;
        t->callback_data = callback_data;

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

        card->driver->send_request(card, &t->packet);
}
EXPORT_SYMBOL(fw_send_request);

struct fw_phy_packet {
        struct fw_packet packet;
        struct completion done;
};

static void
transmit_phy_packet_callback(struct fw_packet *packet,
                             struct fw_card *card, int status)
{
        struct fw_phy_packet *p =
                        container_of(packet, struct fw_phy_packet, packet);

        complete(&p->done);
}

void fw_send_phy_config(struct fw_card *card,
                        int node_id, int generation, int gap_count)
{
        struct fw_phy_packet p;
        u32 data = PHY_IDENTIFIER(PHY_PACKET_CONFIG) |
                   PHY_CONFIG_ROOT_ID(node_id) |
                   PHY_CONFIG_GAP_COUNT(gap_count);

        p.packet.header[0] = data;
        p.packet.header[1] = ~data;
        p.packet.header_length = 8;
        p.packet.payload_length = 0;
        p.packet.speed = SCODE_100;
        p.packet.generation = generation;
        p.packet.callback = transmit_phy_packet_callback;
        init_completion(&p.done);

        card->driver->send_request(card, &p.packet);
        wait_for_completion(&p.done);
}

void fw_flush_transactions(struct fw_card *card)
{
        struct fw_transaction *t, *next;
        struct list_head list;
        unsigned long flags;

        INIT_LIST_HEAD(&list);
        spin_lock_irqsave(&card->lock, flags);
        list_splice_init(&card->transaction_list, &list);
        card->tlabel_mask = 0;
        spin_unlock_irqrestore(&card->lock, flags);

        list_for_each_entry_safe(t, next, &list, link) {
                card->driver->cancel_packet(card, &t->packet);

                /*
                 * At this point cancel_packet will never call the
                 * transaction callback, since we just took all the
                 * transactions out of the list.  So do it here.
                 */
                t->callback(card, RCODE_CANCELLED, NULL, 0, t->callback_data);
        }
}

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

        return NULL;
}

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

        return NULL;
}

static DEFINE_SPINLOCK(address_handler_lock);
static LIST_HEAD(address_handler_list);

const struct fw_address_region fw_high_memory_region =
        { .start = 0x000100000000ULL, .end = 0xffffe0000000ULL,  };
EXPORT_SYMBOL(fw_high_memory_region);

#if 0
const struct fw_address_region fw_low_memory_region =
        { .start = 0x000000000000ULL, .end = 0x000100000000ULL,  };
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  */

/**
 * Allocate a range of addresses in the node space of the OHCI
 * controller.  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.
 *
 * 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.
 * The offset is quadlet-aligned.
 */
int
fw_core_add_address_handler(struct fw_address_handler *handler,
                            const struct fw_address_region *region)
{
        struct fw_address_handler *other;
        unsigned long flags;
        int ret = -EBUSY;

        spin_lock_irqsave(&address_handler_lock, flags);

        handler->offset = roundup(region->start, 4);
        while (handler->offset + handler->length <= region->end) {
                other =
                    lookup_overlapping_address_handler(&address_handler_list,
                                                       handler->offset,
                                                       handler->length);
                if (other != NULL) {
                        handler->offset =
                            roundup(other->offset + other->length, 4);
                } else {
                        list_add_tail(&handler->link, &address_handler_list);
                        ret = 0;
                        break;
                }
        }

        spin_unlock_irqrestore(&address_handler_lock, flags);

        return ret;
}
EXPORT_SYMBOL(fw_core_add_address_handler);

/**
 * Deallocate a range of addresses allocated with fw_allocate.  This
 * will call the associated callback one last time with a the special
 * tcode TCODE_DEALLOCATE, to let the client destroy the registered
 * callback data.  For convenience, the callback parameters offset and
 * length are set to the start and the length respectively for the
 * deallocated region, payload is set to NULL.
 */
void fw_core_remove_address_handler(struct fw_address_handler *handler)
{
        unsigned long flags;

        spin_lock_irqsave(&address_handler_lock, flags);
        list_del(&handler->link);
        spin_unlock_irqrestore(&address_handler_lock, flags);
}
EXPORT_SYMBOL(fw_core_remove_address_handler);

struct fw_request {
        struct fw_packet response;
        u32 request_header[4];
        int ack;
        u32 length;
        u32 data[0];
};

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

        request = container_of(packet, struct fw_request, response);
        kfree(request);
}

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          = HEADER_GET_TCODE(request_header[0]);
        tlabel         = HEADER_GET_TLABEL(request_header[0]);
        source         = HEADER_GET_DESTINATION(request_header[0]);
        destination    = HEADER_GET_SOURCE(request_header[1]);
        extended_tcode = HEADER_GET_EXTENDED_TCODE(request_header[3]);

        response->header[0] =
                HEADER_RETRY(RETRY_1) |
                HEADER_TLABEL(tlabel) |
                HEADER_DESTINATION(destination);
        response->header[1] =
                HEADER_SOURCE(source) |
                HEADER_RCODE(rcode);
        response->header[2] = 0;

        switch (tcode) {
        case TCODE_WRITE_QUADLET_REQUEST:
        case TCODE_WRITE_BLOCK_REQUEST:
                response->header[0] |= HEADER_TCODE(TCODE_WRITE_RESPONSE);
                response->header_length = 12;
                response->payload_length = 0;
                break;

        case TCODE_READ_QUADLET_REQUEST:
                response->header[0] |=
                        HEADER_TCODE(TCODE_READ_QUADLET_RESPONSE);
                if (payload != NULL)
                        response->header[3] = *(u32 *)payload;
                else
                        response->header[3] = 0;
                response->header_length = 16;
                response->payload_length = 0;
                break;

        case TCODE_READ_BLOCK_REQUEST:
        case TCODE_LOCK_REQUEST:
                response->header[0] |= HEADER_TCODE(tcode + 2);
                response->header[3] =
                        HEADER_DATA_LENGTH(length) |
                        HEADER_EXTENDED_TCODE(extended_tcode);
                response->header_length = 16;
                response->payload = payload;
                response->payload_length = length;
                break;

        default:
                BUG();
                return;
        }
}
EXPORT_SYMBOL(fw_fill_response);

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

        request_tcode = HEADER_GET_TCODE(p->header[0]);
        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 = HEADER_GET_DATA_LENGTH(p->header[3]);
                break;

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

        case TCODE_READ_BLOCK_REQUEST:
                data = NULL;
                length = HEADER_GET_DATA_LENGTH(p->header[3]);
                break;

        default:
                BUG();
                return NULL;
        }

        request = kmalloc(sizeof(*request) + length, GFP_ATOMIC);
        if (request == NULL)
                return NULL;

        t = (p->timestamp & 0x1fff) + 4000;
        if (t >= 8000)
                t = (p->timestamp & ~0x1fff) + 0x2000 + t - 8000;
        else
                t = (p->timestamp & ~0x1fff) + t;

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

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

        return request;
}

void
fw_send_response(struct fw_card *card, struct fw_request *request, int rcode)
{
        /*
         * Broadcast packets are reported as ACK_COMPLETE, so this
         * check is sufficient to ensure we don't send response to
         * broadcast packets or posted writes.
         */
        if (request->ack != ACK_PENDING) {
                kfree(request);
                return;
        }

        if (rcode == RCODE_COMPLETE)
                fw_fill_response(&request->response, request->request_header,
                                 rcode, request->data, request->length);
        else
                fw_fill_response(&request->response, request->request_header,
                                 rcode, NULL, 0);

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

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

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

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

        offset      =
                ((unsigned long long)
                 HEADER_GET_OFFSET_HIGH(p->header[1]) << 32) | p->header[2];
        tcode       = HEADER_GET_TCODE(p->header[0]);
        destination = HEADER_GET_DESTINATION(p->header[0]);
        source      = HEADER_GET_SOURCE(p->header[1]);

        spin_lock_irqsave(&address_handler_lock, flags);
        handler = lookup_enclosing_address_handler(&address_handler_list,
                                                   offset, request->length);
        spin_unlock_irqrestore(&address_handler_lock, flags);

        /*
         * FIXME: lookup the fw_node corresponding to the sender of
         * this request and pass that to the address handler instead
         * of the node ID.  We may also want to move the address
         * allocations to fw_node so we only do this callback if the
         * upper layers registered it for this node.
         */

        if (handler == NULL)
                fw_send_response(card, request, RCODE_ADDRESS_ERROR);
        else
                handler->address_callback(card, request,
                                          tcode, destination, source,
                                          p->generation, p->speed, offset,
                                          request->data, request->length,
                                          handler->callback_data);
}
EXPORT_SYMBOL(fw_core_handle_request);

void
fw_core_handle_response(struct fw_card *card, struct fw_packet *p)
{
        struct fw_transaction *t;
        unsigned long flags;
        u32 *data;
        size_t data_length;
        int tcode, tlabel, destination, source, rcode;

        tcode       = HEADER_GET_TCODE(p->header[0]);
        tlabel      = HEADER_GET_TLABEL(p->header[0]);
        destination = HEADER_GET_DESTINATION(p->header[0]);
        source      = HEADER_GET_SOURCE(p->header[1]);
        rcode       = HEADER_GET_RCODE(p->header[1]);

        spin_lock_irqsave(&card->lock, flags);
        list_for_each_entry(t, &card->transaction_list, link) {
                if (t->node_id == source && t->tlabel == tlabel) {
                        list_del(&t->link);
                        card->tlabel_mask &= ~(1 << t->tlabel);
                        break;
                }
        }
        spin_unlock_irqrestore(&card->lock, flags);

        if (&t->link == &card->transaction_list) {
                fw_notify("Unsolicited response (source %x, tlabel %x)\n",
                          source, tlabel);
                return;
        }

        /*
         * FIXME: sanity check packet, is length correct, does tcodes
         * and addresses match.
         */

        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 = HEADER_GET_DATA_LENGTH(p->header[3]);
                break;

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

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

        t->callback(card, rcode, data, data_length, t->callback_data);
}
EXPORT_SYMBOL(fw_core_handle_response);

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, int speed,
                    unsigned long long offset,
                    void *payload, size_t length, void *callback_data)
{
        int i, start, end;
        __be32 *map;

        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;
        end = start + length / 4;
        map = payload;

        for (i = 0; i < length / 4; i++)
                map[i] = cpu_to_be32(card->topology_map[start + i]);

        fw_send_response(card, request, RCODE_COMPLETE);
}

static struct fw_address_handler topology_map = {
        .length                 = 0x200,
        .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
handle_registers(struct fw_card *card, struct fw_request *request,
                 int tcode, int destination, int source,
                 int generation, int speed,
                 unsigned long long offset,
                 void *payload, size_t length, void *callback_data)
{
        int reg = offset & ~CSR_REGISTER_BASE;
        unsigned long long bus_time;
        __be32 *data = payload;

        switch (reg) {
        case CSR_CYCLE_TIME:
        case CSR_BUS_TIME:
                if (!TCODE_IS_READ_REQUEST(tcode) || length != 4) {
                        fw_send_response(card, request, RCODE_TYPE_ERROR);
                        break;
                }

                bus_time = card->driver->get_bus_time(card);
                if (reg == CSR_CYCLE_TIME)
                        *data = cpu_to_be32(bus_time);
                else
                        *data = cpu_to_be32(bus_time >> 25);
                fw_send_response(card, request, RCODE_COMPLETE);
                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;

        case CSR_BUSY_TIMEOUT:
                /* FIXME: Implement this. */
        default:
                fw_send_response(card, request, RCODE_ADDRESS_ERROR);
                break;
        }
}

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

MODULE_AUTHOR("Kristian Hoegsberg <krh@bitplanet.net>");
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 = 0x03d00d1e,
        .key = 0x81000000,
        .data = vendor_textual_descriptor,
};

static struct fw_descriptor model_id_descriptor = {
        .length = ARRAY_SIZE(model_textual_descriptor),
        .immediate = 0x17000001,
        .key = 0x81000000,
        .data = model_textual_descriptor,
};

static int __init fw_core_init(void)
{
        int retval;

        retval = bus_register(&fw_bus_type);
        if (retval < 0)
                return retval;

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

        retval = fw_core_add_address_handler(&topology_map,
                                             &topology_map_region);
        BUG_ON(retval < 0);

        retval = fw_core_add_address_handler(&registers,
                                             &registers_region);
        BUG_ON(retval < 0);

        /* Add the vendor textual descriptor. */
        retval = fw_core_add_descriptor(&vendor_id_descriptor);
        BUG_ON(retval < 0);
        retval = fw_core_add_descriptor(&model_id_descriptor);
        BUG_ON(retval < 0);

        return 0;
}

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

module_init(fw_core_init);
module_exit(fw_core_cleanup);