drivers/firewire/fw-card.c - kernel/msm-4.9 - Gitiles

 /*
  * Copyright (C) 2005-2007  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/crc-itu-t.h>
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/errno.h>
 #include <linux/kref.h>
 #include <linux/module.h>
 #include <linux/mutex.h>

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

 int fw_compute_block_crc(u32 *block)
 {
 	__be32 be32_block[256];
 	int i, length;

 	length = (*block >> 16) & 0xff;
 	for (i = 0; i < length; i++)
 		be32_block[i] = cpu_to_be32(block[i + 1]);
 	*block |= crc_itu_t(0, (u8 *) be32_block, length * 4);

 	return length;
 }

 static DEFINE_MUTEX(card_mutex);
 static LIST_HEAD(card_list);

 static LIST_HEAD(descriptor_list);
 static int descriptor_count;

 #define BIB_CRC(v)		((v) <<  0)
 #define BIB_CRC_LENGTH(v)	((v) << 16)
 #define BIB_INFO_LENGTH(v)	((v) << 24)

 #define BIB_LINK_SPEED(v)	((v) <<  0)
 #define BIB_GENERATION(v)	((v) <<  4)
 #define BIB_MAX_ROM(v)		((v) <<  8)
 #define BIB_MAX_RECEIVE(v)	((v) << 12)
 #define BIB_CYC_CLK_ACC(v)	((v) << 16)
 #define BIB_PMC			((1) << 27)
 #define BIB_BMC			((1) << 28)
 #define BIB_ISC			((1) << 29)
 #define BIB_CMC			((1) << 30)
 #define BIB_IMC			((1) << 31)

 static u32 *
 generate_config_rom(struct fw_card *card, size_t *config_rom_length)
 {
 	struct fw_descriptor *desc;
 	static u32 config_rom[256];
 	int i, j, length;

 	/*
 	 * Initialize contents of config rom buffer.  On the OHCI
 	 * controller, block reads to the config rom accesses the host
 	 * memory, but quadlet read access the hardware bus info block
 	 * registers.  That's just crack, but it means we should make
 	 * sure the contents of bus info block in host memory matches
 	 * the version stored in the OHCI registers.
 	 */

 	memset(config_rom, 0, sizeof(config_rom));
 	config_rom[0] = BIB_CRC_LENGTH(4) | BIB_INFO_LENGTH(4) | BIB_CRC(0);
 	config_rom[1] = 0x31333934;

 	config_rom[2] =
 		BIB_LINK_SPEED(card->link_speed) |
 		BIB_GENERATION(card->config_rom_generation++ % 14 + 2) |
 		BIB_MAX_ROM(2) |
 		BIB_MAX_RECEIVE(card->max_receive) |
 		BIB_BMC | BIB_ISC | BIB_CMC | BIB_IMC;
 	config_rom[3] = card->guid >> 32;
 	config_rom[4] = card->guid;

 	/* Generate root directory. */
 	i = 5;
 	config_rom[i++] = 0;
 	config_rom[i++] = 0x0c0083c0; /* node capabilities */
 	j = i + descriptor_count;

 	/* Generate root directory entries for descriptors. */
 	list_for_each_entry (desc, &descriptor_list, link) {
 		if (desc->immediate > 0)
 			config_rom[i++] = desc->immediate;
 		config_rom[i] = desc->key | (j - i);
 		i++;
 		j += desc->length;
 	}

 	/* Update root directory length. */
 	config_rom[5] = (i - 5 - 1) << 16;

 	/* End of root directory, now copy in descriptors. */
 	list_for_each_entry (desc, &descriptor_list, link) {
 		memcpy(&config_rom[i], desc->data, desc->length * 4);
 		i += desc->length;
 	}

 	/* Calculate CRCs for all blocks in the config rom.  This
 	 * assumes that CRC length and info length are identical for
 	 * the bus info block, which is always the case for this
 	 * implementation. */
 	for (i = 0; i < j; i += length + 1)
 		length = fw_compute_block_crc(config_rom + i);

 	*config_rom_length = j;

 	return config_rom;
 }

 static void
 update_config_roms(void)
 {
 	struct fw_card *card;
 	u32 *config_rom;
 	size_t length;

 	list_for_each_entry (card, &card_list, link) {
 		config_rom = generate_config_rom(card, &length);
 		card->driver->set_config_rom(card, config_rom, length);
 	}
 }

 int
 fw_core_add_descriptor(struct fw_descriptor *desc)
 {
 	size_t i;

 	/*
 	 * Check descriptor is valid; the length of all blocks in the
 	 * descriptor has to add up to exactly the length of the
 	 * block.
 	 */
 	i = 0;
 	while (i < desc->length)
 		i += (desc->data[i] >> 16) + 1;

 	if (i != desc->length)
 		return -EINVAL;

 	mutex_lock(&card_mutex);

 	list_add_tail(&desc->link, &descriptor_list);
 	descriptor_count++;
 	if (desc->immediate > 0)
 		descriptor_count++;
 	update_config_roms();

 	mutex_unlock(&card_mutex);

 	return 0;
 }

 void
 fw_core_remove_descriptor(struct fw_descriptor *desc)
 {
 	mutex_lock(&card_mutex);

 	list_del(&desc->link);
 	descriptor_count--;
 	if (desc->immediate > 0)
 		descriptor_count--;
 	update_config_roms();

 	mutex_unlock(&card_mutex);
 }

 static const char gap_count_table[] = {
 	63, 5, 7, 8, 10, 13, 16, 18, 21, 24, 26, 29, 32, 35, 37, 40
 };

 void
 fw_schedule_bm_work(struct fw_card *card, unsigned long delay)
 {
 	int scheduled;

 	fw_card_get(card);
 	scheduled = schedule_delayed_work(&card->work, delay);
 	if (!scheduled)
 		fw_card_put(card);
 }

 static void
 fw_card_bm_work(struct work_struct *work)
 {
 	struct fw_card *card = container_of(work, struct fw_card, work.work);
 	struct fw_device *root_device;
 	struct fw_node *root_node, *local_node;
 	unsigned long flags;
 	int root_id, new_root_id, irm_id, gap_count, generation, grace, rcode;
 	bool do_reset = false;
 	bool root_device_is_running;
 	bool root_device_is_cmc;
 	__be32 lock_data[2];

 	spin_lock_irqsave(&card->lock, flags);
 	local_node = card->local_node;
 	root_node  = card->root_node;

 	if (local_node == NULL) {
 		spin_unlock_irqrestore(&card->lock, flags);
 		goto out_put_card;
 	}
 	fw_node_get(local_node);
 	fw_node_get(root_node);

 	generation = card->generation;
 	root_device = root_node->data;
 	root_device_is_running = root_device &&
 			atomic_read(&root_device->state) == FW_DEVICE_RUNNING;
 	root_device_is_cmc = root_device && root_device->cmc;
 	root_id = root_node->node_id;
 	grace = time_after(jiffies, card->reset_jiffies + DIV_ROUND_UP(HZ, 10));

 	if (is_next_generation(generation, card->bm_generation) ||
 	    (card->bm_generation != generation && grace)) {
 		/*
 		 * This first step is to figure out who is IRM and
 		 * then try to become bus manager.  If the IRM is not
 		 * well defined (e.g. does not have an active link
 		 * layer or does not responds to our lock request, we
 		 * will have to do a little vigilante bus management.
 		 * In that case, we do a goto into the gap count logic
 		 * so that when we do the reset, we still optimize the
 		 * gap count.  That could well save a reset in the
 		 * next generation.
 		 */

 		irm_id = card->irm_node->node_id;
 		if (!card->irm_node->link_on) {
 			new_root_id = local_node->node_id;
 			fw_notify("IRM has link off, making local node (%02x) root.\n",
 				  new_root_id);
 			goto pick_me;
 		}

 		lock_data[0] = cpu_to_be32(0x3f);
 		lock_data[1] = cpu_to_be32(local_node->node_id);

 		spin_unlock_irqrestore(&card->lock, flags);

 		rcode = fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
 				irm_id, generation, SCODE_100,
 				CSR_REGISTER_BASE + CSR_BUS_MANAGER_ID,
 				lock_data, sizeof(lock_data));

 		if (rcode == RCODE_GENERATION)
 			/* Another bus reset, BM work has been rescheduled. */
 			goto out;

 		if (rcode == RCODE_COMPLETE &&
 		    lock_data[0] != cpu_to_be32(0x3f))
 			/* Somebody else is BM, let them do the work. */
 			goto out;

 		spin_lock_irqsave(&card->lock, flags);

 		if (rcode != RCODE_COMPLETE) {
 			/*
 			 * The lock request failed, maybe the IRM
 			 * isn't really IRM capable after all. Let's
 			 * do a bus reset and pick the local node as
 			 * root, and thus, IRM.
 			 */
 			new_root_id = local_node->node_id;
 			fw_notify("BM lock failed, making local node (%02x) root.\n",
 				  new_root_id);
 			goto pick_me;
 		}
 	} else if (card->bm_generation != generation) {
 		/*
 		 * OK, we weren't BM in the last generation, and it's
 		 * less than 100ms since last bus reset. Reschedule
 		 * this task 100ms from now.
 		 */
 		spin_unlock_irqrestore(&card->lock, flags);
 		fw_schedule_bm_work(card, DIV_ROUND_UP(HZ, 10));
 		goto out;
 	}

 	/*
 	 * We're bus manager for this generation, so next step is to
 	 * make sure we have an active cycle master and do gap count
 	 * optimization.
 	 */
 	card->bm_generation = generation;

 	if (root_device == NULL) {
 		/*
 		 * Either link_on is false, or we failed to read the
 		 * config rom.  In either case, pick another root.
 		 */
 		new_root_id = local_node->node_id;
 	} else if (!root_device_is_running) {
 		/*
 		 * If we haven't probed this device yet, bail out now
 		 * and let's try again once that's done.
 		 */
 		spin_unlock_irqrestore(&card->lock, flags);
 		goto out;
 	} else if (root_device_is_cmc) {
 		/*
 		 * FIXME: I suppose we should set the cmstr bit in the
 		 * STATE_CLEAR register of this node, as described in
 		 * 1394-1995, 8.4.2.6.  Also, send out a force root
 		 * packet for this node.
 		 */
 		new_root_id = root_id;
 	} else {
 		/*
 		 * Current root has an active link layer and we
 		 * successfully read the config rom, but it's not
 		 * cycle master capable.
 		 */
 		new_root_id = local_node->node_id;
 	}

  pick_me:
 	/*
 	 * Pick a gap count from 1394a table E-1.  The table doesn't cover
 	 * the typically much larger 1394b beta repeater delays though.
 	 */
 	if (!card->beta_repeaters_present &&
 	    root_node->max_hops < ARRAY_SIZE(gap_count_table))
 		gap_count = gap_count_table[root_node->max_hops];
 	else
 		gap_count = 63;

 	/*
 	 * Finally, figure out if we should do a reset or not.  If we have
 	 * done less than 5 resets with the same physical topology and we
 	 * have either a new root or a new gap count setting, let's do it.
 	 */

 	if (card->bm_retries++ < 5 &&
 	    (card->gap_count != gap_count || new_root_id != root_id))
 		do_reset = true;

 	spin_unlock_irqrestore(&card->lock, flags);

 	if (do_reset) {
 		fw_notify("phy config: card %d, new root=%x, gap_count=%d\n",
 			  card->index, new_root_id, gap_count);
 		fw_send_phy_config(card, new_root_id, generation, gap_count);
 		fw_core_initiate_bus_reset(card, 1);
 	}
  out:
 	fw_node_put(root_node);
 	fw_node_put(local_node);
  out_put_card:
 	fw_card_put(card);
 }

 static void
 flush_timer_callback(unsigned long data)
 {
 	struct fw_card *card = (struct fw_card *)data;

 	fw_flush_transactions(card);
 }

 void
 fw_card_initialize(struct fw_card *card, const struct fw_card_driver *driver,
 		   struct device *device)
 {
 	static atomic_t index = ATOMIC_INIT(-1);

 	card->index = atomic_inc_return(&index);
 	card->driver = driver;
 	card->device = device;
 	card->current_tlabel = 0;
 	card->tlabel_mask = 0;
 	card->color = 0;
 	card->broadcast_channel = BROADCAST_CHANNEL_INITIAL;

 	kref_init(&card->kref);
 	init_completion(&card->done);
 	INIT_LIST_HEAD(&card->transaction_list);
 	spin_lock_init(&card->lock);
 	setup_timer(&card->flush_timer,
 		    flush_timer_callback, (unsigned long)card);

 	card->local_node = NULL;

 	INIT_DELAYED_WORK(&card->work, fw_card_bm_work);
 }
 EXPORT_SYMBOL(fw_card_initialize);

 int
 fw_card_add(struct fw_card *card,
 	    u32 max_receive, u32 link_speed, u64 guid)
 {
 	u32 *config_rom;
 	size_t length;

 	card->max_receive = max_receive;
 	card->link_speed = link_speed;
 	card->guid = guid;

 	mutex_lock(&card_mutex);
 	config_rom = generate_config_rom(card, &length);
 	list_add_tail(&card->link, &card_list);
 	mutex_unlock(&card_mutex);

 	return card->driver->enable(card, config_rom, length);
 }
 EXPORT_SYMBOL(fw_card_add);


 /*
  * The next few functions implements a dummy driver that use once a
  * card driver shuts down an fw_card.  This allows the driver to
  * cleanly unload, as all IO to the card will be handled by the dummy
  * driver instead of calling into the (possibly) unloaded module.  The
  * dummy driver just fails all IO.
  */

 static int
 dummy_enable(struct fw_card *card, u32 *config_rom, size_t length)
 {
 	BUG();
 	return -1;
 }

 static int
 dummy_update_phy_reg(struct fw_card *card, int address,
 		     int clear_bits, int set_bits)
 {
 	return -ENODEV;
 }

 static int
 dummy_set_config_rom(struct fw_card *card,
 		     u32 *config_rom, size_t length)
 {
 	/*
 	 * We take the card out of card_list before setting the dummy
 	 * driver, so this should never get called.
 	 */
 	BUG();
 	return -1;
 }

 static void
 dummy_send_request(struct fw_card *card, struct fw_packet *packet)
 {
 	packet->callback(packet, card, -ENODEV);
 }

 static void
 dummy_send_response(struct fw_card *card, struct fw_packet *packet)
 {
 	packet->callback(packet, card, -ENODEV);
 }

 static int
 dummy_cancel_packet(struct fw_card *card, struct fw_packet *packet)
 {
 	return -ENOENT;
 }

 static int
 dummy_enable_phys_dma(struct fw_card *card,
 		      int node_id, int generation)
 {
 	return -ENODEV;
 }

 static struct fw_card_driver dummy_driver = {
 	.enable          = dummy_enable,
 	.update_phy_reg  = dummy_update_phy_reg,
 	.set_config_rom  = dummy_set_config_rom,
 	.send_request    = dummy_send_request,
 	.cancel_packet   = dummy_cancel_packet,
 	.send_response   = dummy_send_response,
 	.enable_phys_dma = dummy_enable_phys_dma,
 };

 void
 fw_card_release(struct kref *kref)
 {
 	struct fw_card *card = container_of(kref, struct fw_card, kref);

 	complete(&card->done);
 }

 void
 fw_core_remove_card(struct fw_card *card)
 {
 	card->driver->update_phy_reg(card, 4,
 				     PHY_LINK_ACTIVE | PHY_CONTENDER, 0);
 	fw_core_initiate_bus_reset(card, 1);

 	mutex_lock(&card_mutex);
 	list_del_init(&card->link);
 	mutex_unlock(&card_mutex);

 	/* Set up the dummy driver. */
 	card->driver = &dummy_driver;

 	fw_destroy_nodes(card);

 	/* Wait for all users, especially device workqueue jobs, to finish. */
 	fw_card_put(card);
 	wait_for_completion(&card->done);

 	WARN_ON(!list_empty(&card->transaction_list));
 	del_timer_sync(&card->flush_timer);
 }
 EXPORT_SYMBOL(fw_core_remove_card);

 int
 fw_core_initiate_bus_reset(struct fw_card *card, int short_reset)
 {
 	int reg = short_reset ? 5 : 1;
 	int bit = short_reset ? PHY_BUS_SHORT_RESET : PHY_BUS_RESET;

 	return card->driver->update_phy_reg(card, reg, 0, bit);
 }
 EXPORT_SYMBOL(fw_core_initiate_bus_reset);
	/*
	* Copyright (C) 2005-2007 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/crc-itu-t.h>
	#include <linux/delay.h>
	#include <linux/device.h>
	#include <linux/errno.h>
	#include <linux/kref.h>
	#include <linux/module.h>
	#include <linux/mutex.h>

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

	int fw_compute_block_crc(u32 *block)
	{
	__be32 be32_block[256];
	int i, length;

	length = (*block >> 16) & 0xff;
	for (i = 0; i < length; i++)
	be32_block[i] = cpu_to_be32(block[i + 1]);
	block \|= crc_itu_t(0, (u8 ) be32_block, length * 4);

	return length;
	}

	static DEFINE_MUTEX(card_mutex);
	static LIST_HEAD(card_list);

	static LIST_HEAD(descriptor_list);
	static int descriptor_count;

	#define BIB_CRC(v) ((v) << 0)
	#define BIB_CRC_LENGTH(v) ((v) << 16)
	#define BIB_INFO_LENGTH(v) ((v) << 24)

	#define BIB_LINK_SPEED(v) ((v) << 0)
	#define BIB_GENERATION(v) ((v) << 4)
	#define BIB_MAX_ROM(v) ((v) << 8)
	#define BIB_MAX_RECEIVE(v) ((v) << 12)
	#define BIB_CYC_CLK_ACC(v) ((v) << 16)
	#define BIB_PMC ((1) << 27)
	#define BIB_BMC ((1) << 28)
	#define BIB_ISC ((1) << 29)
	#define BIB_CMC ((1) << 30)
	#define BIB_IMC ((1) << 31)

	static u32 *
	generate_config_rom(struct fw_card card, size_t config_rom_length)
	{
	struct fw_descriptor *desc;
	static u32 config_rom[256];
	int i, j, length;

	/*
	* Initialize contents of config rom buffer. On the OHCI
	* controller, block reads to the config rom accesses the host
	* memory, but quadlet read access the hardware bus info block
	* registers. That's just crack, but it means we should make
	* sure the contents of bus info block in host memory matches
	* the version stored in the OHCI registers.
	*/

	memset(config_rom, 0, sizeof(config_rom));
	config_rom[0] = BIB_CRC_LENGTH(4) \| BIB_INFO_LENGTH(4) \| BIB_CRC(0);
	config_rom[1] = 0x31333934;

	config_rom[2] =
	BIB_LINK_SPEED(card->link_speed) \|
	BIB_GENERATION(card->config_rom_generation++ % 14 + 2) \|
	BIB_MAX_ROM(2) \|
	BIB_MAX_RECEIVE(card->max_receive) \|
	BIB_BMC \| BIB_ISC \| BIB_CMC \| BIB_IMC;
	config_rom[3] = card->guid >> 32;
	config_rom[4] = card->guid;

	/* Generate root directory. */
	i = 5;
	config_rom[i++] = 0;
	config_rom[i++] = 0x0c0083c0; /* node capabilities */
	j = i + descriptor_count;

	/* Generate root directory entries for descriptors. */
	list_for_each_entry (desc, &descriptor_list, link) {
	if (desc->immediate > 0)
	config_rom[i++] = desc->immediate;
	config_rom[i] = desc->key \| (j - i);
	i++;
	j += desc->length;
	}

	/* Update root directory length. */
	config_rom[5] = (i - 5 - 1) << 16;

	/* End of root directory, now copy in descriptors. */
	list_for_each_entry (desc, &descriptor_list, link) {
	memcpy(&config_rom[i], desc->data, desc->length * 4);
	i += desc->length;
	}

	/* Calculate CRCs for all blocks in the config rom. This
	* assumes that CRC length and info length are identical for
	* the bus info block, which is always the case for this
	* implementation. */
	for (i = 0; i < j; i += length + 1)
	length = fw_compute_block_crc(config_rom + i);

	*config_rom_length = j;

	return config_rom;
	}

	static void
	update_config_roms(void)
	{
	struct fw_card *card;
	u32 *config_rom;
	size_t length;

	list_for_each_entry (card, &card_list, link) {
	config_rom = generate_config_rom(card, &length);
	card->driver->set_config_rom(card, config_rom, length);
	}
	}

	int
	fw_core_add_descriptor(struct fw_descriptor *desc)
	{
	size_t i;

	/*
	* Check descriptor is valid; the length of all blocks in the
	* descriptor has to add up to exactly the length of the
	* block.
	*/
	i = 0;
	while (i < desc->length)
	i += (desc->data[i] >> 16) + 1;

	if (i != desc->length)
	return -EINVAL;

	mutex_lock(&card_mutex);

	list_add_tail(&desc->link, &descriptor_list);
	descriptor_count++;
	if (desc->immediate > 0)
	descriptor_count++;
	update_config_roms();

	mutex_unlock(&card_mutex);

	return 0;
	}

	void
	fw_core_remove_descriptor(struct fw_descriptor *desc)
	{
	mutex_lock(&card_mutex);

	list_del(&desc->link);
	descriptor_count--;
	if (desc->immediate > 0)
	descriptor_count--;
	update_config_roms();

	mutex_unlock(&card_mutex);
	}

	static const char gap_count_table[] = {
	63, 5, 7, 8, 10, 13, 16, 18, 21, 24, 26, 29, 32, 35, 37, 40
	};

	void
	fw_schedule_bm_work(struct fw_card *card, unsigned long delay)
	{
	int scheduled;

	fw_card_get(card);
	scheduled = schedule_delayed_work(&card->work, delay);
	if (!scheduled)
	fw_card_put(card);
	}

	static void
	fw_card_bm_work(struct work_struct *work)
	{
	struct fw_card *card = container_of(work, struct fw_card, work.work);
	struct fw_device *root_device;
	struct fw_node root_node, local_node;
	unsigned long flags;
	int root_id, new_root_id, irm_id, gap_count, generation, grace, rcode;
	bool do_reset = false;
	bool root_device_is_running;
	bool root_device_is_cmc;
	__be32 lock_data[2];

	spin_lock_irqsave(&card->lock, flags);
	local_node = card->local_node;
	root_node = card->root_node;

	if (local_node == NULL) {
	spin_unlock_irqrestore(&card->lock, flags);
	goto out_put_card;
	}
	fw_node_get(local_node);
	fw_node_get(root_node);

	generation = card->generation;
	root_device = root_node->data;
	root_device_is_running = root_device &&
	atomic_read(&root_device->state) == FW_DEVICE_RUNNING;
	root_device_is_cmc = root_device && root_device->cmc;
	root_id = root_node->node_id;
	grace = time_after(jiffies, card->reset_jiffies + DIV_ROUND_UP(HZ, 10));

	if (is_next_generation(generation, card->bm_generation) \|\|
	(card->bm_generation != generation && grace)) {
	/*
	* This first step is to figure out who is IRM and
	* then try to become bus manager. If the IRM is not
	* well defined (e.g. does not have an active link
	* layer or does not responds to our lock request, we
	* will have to do a little vigilante bus management.
	* In that case, we do a goto into the gap count logic
	* so that when we do the reset, we still optimize the
	* gap count. That could well save a reset in the
	* next generation.
	*/

	irm_id = card->irm_node->node_id;
	if (!card->irm_node->link_on) {
	new_root_id = local_node->node_id;
	fw_notify("IRM has link off, making local node (%02x) root.\n",
	new_root_id);
	goto pick_me;
	}

	lock_data[0] = cpu_to_be32(0x3f);
	lock_data[1] = cpu_to_be32(local_node->node_id);

	spin_unlock_irqrestore(&card->lock, flags);

	rcode = fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
	irm_id, generation, SCODE_100,
	CSR_REGISTER_BASE + CSR_BUS_MANAGER_ID,
	lock_data, sizeof(lock_data));

	if (rcode == RCODE_GENERATION)
	/* Another bus reset, BM work has been rescheduled. */
	goto out;

	if (rcode == RCODE_COMPLETE &&
	lock_data[0] != cpu_to_be32(0x3f))
	/* Somebody else is BM, let them do the work. */
	goto out;

	spin_lock_irqsave(&card->lock, flags);

	if (rcode != RCODE_COMPLETE) {
	/*
	* The lock request failed, maybe the IRM
	* isn't really IRM capable after all. Let's
	* do a bus reset and pick the local node as
	* root, and thus, IRM.
	*/
	new_root_id = local_node->node_id;
	fw_notify("BM lock failed, making local node (%02x) root.\n",
	new_root_id);
	goto pick_me;
	}
	} else if (card->bm_generation != generation) {
	/*
	* OK, we weren't BM in the last generation, and it's
	* less than 100ms since last bus reset. Reschedule
	* this task 100ms from now.
	*/
	spin_unlock_irqrestore(&card->lock, flags);
	fw_schedule_bm_work(card, DIV_ROUND_UP(HZ, 10));
	goto out;
	}

	/*
	* We're bus manager for this generation, so next step is to
	* make sure we have an active cycle master and do gap count
	* optimization.
	*/
	card->bm_generation = generation;

	if (root_device == NULL) {
	/*
	* Either link_on is false, or we failed to read the
	* config rom. In either case, pick another root.
	*/
	new_root_id = local_node->node_id;
	} else if (!root_device_is_running) {
	/*
	* If we haven't probed this device yet, bail out now
	* and let's try again once that's done.
	*/
	spin_unlock_irqrestore(&card->lock, flags);
	goto out;
	} else if (root_device_is_cmc) {
	/*
	* FIXME: I suppose we should set the cmstr bit in the
	* STATE_CLEAR register of this node, as described in
	* 1394-1995, 8.4.2.6. Also, send out a force root
	* packet for this node.
	*/
	new_root_id = root_id;
	} else {
	/*
	* Current root has an active link layer and we
	* successfully read the config rom, but it's not
	* cycle master capable.
	*/
	new_root_id = local_node->node_id;
	}

	pick_me:
	/*
	* Pick a gap count from 1394a table E-1. The table doesn't cover
	* the typically much larger 1394b beta repeater delays though.
	*/
	if (!card->beta_repeaters_present &&
	root_node->max_hops < ARRAY_SIZE(gap_count_table))
	gap_count = gap_count_table[root_node->max_hops];
	else
	gap_count = 63;

	/*
	* Finally, figure out if we should do a reset or not. If we have
	* done less than 5 resets with the same physical topology and we
	* have either a new root or a new gap count setting, let's do it.
	*/

	if (card->bm_retries++ < 5 &&
	(card->gap_count != gap_count \|\| new_root_id != root_id))
	do_reset = true;

	spin_unlock_irqrestore(&card->lock, flags);

	if (do_reset) {
	fw_notify("phy config: card %d, new root=%x, gap_count=%d\n",
	card->index, new_root_id, gap_count);
	fw_send_phy_config(card, new_root_id, generation, gap_count);
	fw_core_initiate_bus_reset(card, 1);
	}
	out:
	fw_node_put(root_node);
	fw_node_put(local_node);
	out_put_card:
	fw_card_put(card);
	}

	static void
	flush_timer_callback(unsigned long data)
	{
	struct fw_card card = (struct fw_card )data;

	fw_flush_transactions(card);
	}

	void
	fw_card_initialize(struct fw_card card, const struct fw_card_driver driver,
	struct device *device)
	{
	static atomic_t index = ATOMIC_INIT(-1);

	card->index = atomic_inc_return(&index);
	card->driver = driver;
	card->device = device;
	card->current_tlabel = 0;
	card->tlabel_mask = 0;
	card->color = 0;
	card->broadcast_channel = BROADCAST_CHANNEL_INITIAL;

	kref_init(&card->kref);
	init_completion(&card->done);
	INIT_LIST_HEAD(&card->transaction_list);
	spin_lock_init(&card->lock);
	setup_timer(&card->flush_timer,
	flush_timer_callback, (unsigned long)card);

	card->local_node = NULL;

	INIT_DELAYED_WORK(&card->work, fw_card_bm_work);
	}
	EXPORT_SYMBOL(fw_card_initialize);

	int
	fw_card_add(struct fw_card *card,
	u32 max_receive, u32 link_speed, u64 guid)
	{
	u32 *config_rom;
	size_t length;

	card->max_receive = max_receive;
	card->link_speed = link_speed;
	card->guid = guid;

	mutex_lock(&card_mutex);
	config_rom = generate_config_rom(card, &length);
	list_add_tail(&card->link, &card_list);
	mutex_unlock(&card_mutex);

	return card->driver->enable(card, config_rom, length);
	}
	EXPORT_SYMBOL(fw_card_add);


	/*
	* The next few functions implements a dummy driver that use once a
	* card driver shuts down an fw_card. This allows the driver to
	* cleanly unload, as all IO to the card will be handled by the dummy
	* driver instead of calling into the (possibly) unloaded module. The
	* dummy driver just fails all IO.
	*/

	static int
	dummy_enable(struct fw_card card, u32 config_rom, size_t length)
	{
	BUG();
	return -1;
	}

	static int
	dummy_update_phy_reg(struct fw_card *card, int address,
	int clear_bits, int set_bits)
	{
	return -ENODEV;
	}

	static int
	dummy_set_config_rom(struct fw_card *card,
	u32 *config_rom, size_t length)
	{
	/*
	* We take the card out of card_list before setting the dummy
	* driver, so this should never get called.
	*/
	BUG();
	return -1;
	}

	static void
	dummy_send_request(struct fw_card card, struct fw_packet packet)
	{
	packet->callback(packet, card, -ENODEV);
	}

	static void
	dummy_send_response(struct fw_card card, struct fw_packet packet)
	{
	packet->callback(packet, card, -ENODEV);
	}

	static int
	dummy_cancel_packet(struct fw_card card, struct fw_packet packet)
	{
	return -ENOENT;
	}

	static int
	dummy_enable_phys_dma(struct fw_card *card,
	int node_id, int generation)
	{
	return -ENODEV;
	}

	static struct fw_card_driver dummy_driver = {
	.enable = dummy_enable,
	.update_phy_reg = dummy_update_phy_reg,
	.set_config_rom = dummy_set_config_rom,
	.send_request = dummy_send_request,
	.cancel_packet = dummy_cancel_packet,
	.send_response = dummy_send_response,
	.enable_phys_dma = dummy_enable_phys_dma,
	};

	void
	fw_card_release(struct kref *kref)
	{
	struct fw_card *card = container_of(kref, struct fw_card, kref);

	complete(&card->done);
	}

	void
	fw_core_remove_card(struct fw_card *card)
	{
	card->driver->update_phy_reg(card, 4,
	PHY_LINK_ACTIVE \| PHY_CONTENDER, 0);
	fw_core_initiate_bus_reset(card, 1);

	mutex_lock(&card_mutex);
	list_del_init(&card->link);
	mutex_unlock(&card_mutex);

	/* Set up the dummy driver. */
	card->driver = &dummy_driver;

	fw_destroy_nodes(card);

	/* Wait for all users, especially device workqueue jobs, to finish. */
	fw_card_put(card);
	wait_for_completion(&card->done);

	WARN_ON(!list_empty(&card->transaction_list));
	del_timer_sync(&card->flush_timer);
	}
	EXPORT_SYMBOL(fw_core_remove_card);

	int
	fw_core_initiate_bus_reset(struct fw_card *card, int short_reset)
	{
	int reg = short_reset ? 5 : 1;
	int bit = short_reset ? PHY_BUS_SHORT_RESET : PHY_BUS_RESET;

	return card->driver->update_phy_reg(card, reg, 0, bit);
	}
	EXPORT_SYMBOL(fw_core_initiate_bus_reset);