/* * 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/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 <asm/semaphore.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, insted 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); static void transmit_phy_packet_callback(struct fw_packet *packet, struct fw_card *card, int status) { kfree(packet); } static void send_phy_packet(struct fw_card *card, u32 data, int generation) { struct fw_packet *packet; packet = kzalloc(sizeof(*packet), GFP_ATOMIC); if (packet == NULL) return; packet->header[0] = data; packet->header[1] = ~data; packet->header_length = 8; packet->payload_length = 0; packet->speed = SCODE_100; packet->generation = generation; packet->callback = transmit_phy_packet_callback; card->driver->send_request(card, packet); } void fw_send_phy_config(struct fw_card *card, int node_id, int generation, int gap_count) { u32 q; q = PHY_IDENTIFIER(PHY_PACKET_CONFIG) | PHY_CONFIG_ROOT_ID(node_id) | PHY_CONFIG_GAP_COUNT(gap_count); send_phy_packet(card, q, generation); } 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_low_memory_region = { .start = 0x000000000000ULL, .end = 0x000100000000ULL, }; const struct fw_address_region fw_high_memory_region = { .start = 0x000100000000ULL, .end = 0xffffe0000000ULL, }; const struct fw_address_region fw_private_region = { .start = 0xffffe0000000ULL, .end = 0xfffff0000000ULL, }; const struct fw_address_region fw_csr_region = { .start = 0xfffff0000000ULL, .end = 0xfffff0000800ULL, }; const struct fw_address_region fw_unit_space_region = { .start = 0xfffff0000900ULL, .end = 0x1000000000000ULL, }; EXPORT_SYMBOL(fw_low_memory_region); EXPORT_SYMBOL(fw_high_memory_region); EXPORT_SYMBOL(fw_private_region); EXPORT_SYMBOL(fw_csr_region); EXPORT_SYMBOL(fw_unit_space_region); /** * 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[0]); 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; } 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 = 0xfffff0001000ull, .end = 0xfffff0001400ull, }; 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; u32 *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 = 0xfffff0000000ull, .end = 0xfffff0000400ull, }; 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(®isters, ®isters_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);