/*
   * 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/bug.h>

  #include <linux/completion.h>
  #include <linux/crc-itu-t.h>

  #include <linux/device.h>

  #include <linux/errno.h>

  #include <linux/firewire.h>
  #include <linux/firewire-constants.h>

  #include <linux/jiffies.h>
  #include <linux/kernel.h>

  #include <linux/kref.h>

  #include <linux/list.h>

  #include <linux/module.h>

  #include <linux/mutex.h>

  #include <linux/spinlock.h>

  #include <linux/workqueue.h>

  #include <linux/atomic.h>

  #include <asm/byteorder.h>

  #include "core.h"

  int fw_compute_block_crc(__be32 *block)

  {
  	int length;
  	u16 crc;
  
  	length = (be32_to_cpu(block[0]) >> 16) & 0xff;
  	crc = crc_itu_t(0, (u8 *)&block[1], length * 4);
  	*block |= cpu_to_be32(crc);
  
  	return length;
  }

  static DEFINE_MUTEX(card_mutex);

  static LIST_HEAD(card_list);
  
  static LIST_HEAD(descriptor_list);
  static int descriptor_count;

  static __be32 tmp_config_rom[256];

  /* ROM header, bus info block, root dir header, capabilities = 7 quadlets */
  static size_t config_rom_length = 1 + 4 + 1 + 1;

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

  #define BIB_BUS_NAME		0x31333934 /* "1394" */

  #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_IRMC		((1) << 31)
  #define NODE_CAPABILITIES	0x0c0083c0 /* per IEEE 1394 clause 8.3.2.6.5.2 */

  /*
   * IEEE-1394 specifies a default SPLIT_TIMEOUT value of 800 cycles (100 ms),
   * but we have to make it longer because there are many devices whose firmware
   * is just too slow for that.
   */
  #define DEFAULT_SPLIT_TIMEOUT	(2 * 8000)

  #define CANON_OUI		0x000085

  static void generate_config_rom(struct fw_card *card, __be32 *config_rom)

  {
  	struct fw_descriptor *desc;

  	int i, j, k, 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.
  	 */

  	config_rom[0] = cpu_to_be32(
  		BIB_CRC_LENGTH(4) | BIB_INFO_LENGTH(4) | BIB_CRC(0));

  	config_rom[1] = cpu_to_be32(BIB_BUS_NAME);

  	config_rom[2] = cpu_to_be32(

  		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_IRMC);

  	config_rom[3] = cpu_to_be32(card->guid >> 32);
  	config_rom[4] = cpu_to_be32(card->guid);

  
  	/* Generate root directory. */

  	config_rom[6] = cpu_to_be32(NODE_CAPABILITIES);

  	i = 7;
  	j = 7 + descriptor_count;

  
  	/* Generate root directory entries for descriptors. */
  	list_for_each_entry (desc, &descriptor_list, link) {

  		if (desc->immediate > 0)

  			config_rom[i++] = cpu_to_be32(desc->immediate);
  		config_rom[i] = cpu_to_be32(desc->key | (j - i));

  		i++;
  		j += desc->length;
  	}
  
  	/* Update root directory length. */

  	config_rom[5] = cpu_to_be32((i - 5 - 1) << 16);

  
  	/* End of root directory, now copy in descriptors. */
  	list_for_each_entry (desc, &descriptor_list, link) {

  		for (k = 0; k < desc->length; k++)
  			config_rom[i + k] = cpu_to_be32(desc->data[k]);

  		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);

  	WARN_ON(j != config_rom_length);

  }

  static void update_config_roms(void)

  {
  	struct fw_card *card;

  
  	list_for_each_entry (card, &card_list, link) {

  		generate_config_rom(card, tmp_config_rom);
  		card->driver->set_config_rom(card, tmp_config_rom,
  					     config_rom_length);

  	}
  }

  static size_t required_space(struct fw_descriptor *desc)
  {
  	/* descriptor + entry into root dir + optional immediate entry */
  	return desc->length + 1 + (desc->immediate > 0 ? 1 : 0);
  }

  int fw_core_add_descriptor(struct fw_descriptor *desc)

  {
  	size_t i;

  	int ret;

  	/*
  	 * 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);

  	if (config_rom_length + required_space(desc) > 256) {
  		ret = -EBUSY;
  	} else {
  		list_add_tail(&desc->link, &descriptor_list);
  		config_rom_length += required_space(desc);

  		descriptor_count++;

  		if (desc->immediate > 0)
  			descriptor_count++;
  		update_config_roms();
  		ret = 0;
  	}

  	mutex_unlock(&card_mutex);

  	return ret;

  }

  EXPORT_SYMBOL(fw_core_add_descriptor);

  void fw_core_remove_descriptor(struct fw_descriptor *desc)

  {

  	mutex_lock(&card_mutex);

  
  	list_del(&desc->link);

  	config_rom_length -= required_space(desc);

  	descriptor_count--;

  	if (desc->immediate > 0)
  		descriptor_count--;

  	update_config_roms();

  	mutex_unlock(&card_mutex);

  }

  EXPORT_SYMBOL(fw_core_remove_descriptor);

  static int reset_bus(struct fw_card *card, bool 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);
  }
  
  void fw_schedule_bus_reset(struct fw_card *card, bool delayed, bool short_reset)
  {
  	/* We don't try hard to sort out requests of long vs. short resets. */
  	card->br_short = short_reset;
  
  	/* Use an arbitrary short delay to combine multiple reset requests. */
  	fw_card_get(card);

  	if (!queue_delayed_work(fw_workqueue, &card->br_work,

  				delayed ? DIV_ROUND_UP(HZ, 100) : 0))

  		fw_card_put(card);
  }
  EXPORT_SYMBOL(fw_schedule_bus_reset);
  
  static void br_work(struct work_struct *work)
  {
  	struct fw_card *card = container_of(work, struct fw_card, br_work.work);
  
  	/* Delay for 2s after last reset per IEEE 1394 clause 8.2.1. */
  	if (card->reset_jiffies != 0 &&

  	    time_before64(get_jiffies_64(), card->reset_jiffies + 2 * HZ)) {

  		if (!queue_delayed_work(fw_workqueue, &card->br_work, 2 * HZ))

  			fw_card_put(card);
  		return;
  	}
  
  	fw_send_phy_config(card, FW_PHY_CONFIG_NO_NODE_ID, card->generation,
  			   FW_PHY_CONFIG_CURRENT_GAP_COUNT);
  	reset_bus(card, card->br_short);
  	fw_card_put(card);
  }

  static void allocate_broadcast_channel(struct fw_card *card, int generation)

  {

  	int channel, bandwidth = 0;

  	if (!card->broadcast_channel_allocated) {
  		fw_iso_resource_manage(card, generation, 1ULL << 31,

  				       &channel, &bandwidth, true);

  		if (channel != 31) {
  			fw_notify("failed to allocate broadcast channel
  ");
  			return;
  		}

  		card->broadcast_channel_allocated = true;

  	}

  
  	device_for_each_child(card->device, (void *)(long)generation,
  			      fw_device_set_broadcast_channel);

  }

  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)

  {

  	fw_card_get(card);

  	if (!schedule_delayed_work(&card->bm_work, delay))

  		fw_card_put(card);
  }

  static void bm_work(struct work_struct *work)

  {

  	struct fw_card *card = container_of(work, struct fw_card, bm_work.work);

  	struct fw_device *root_device, *irm_device;

  	struct fw_node *root_node;

  	int root_id, new_root_id, irm_id, bm_id, local_id;

  	int gap_count, generation, grace, rcode;

  	bool do_reset = false;

  	bool root_device_is_running;
  	bool root_device_is_cmc;

  	bool irm_is_1394_1995_only;

  	bool keep_this_irm;

  	__be32 transaction_data[2];

  	spin_lock_irq(&card->lock);

  	if (card->local_node == NULL) {

  		spin_unlock_irq(&card->lock);

  		goto out_put_card;

  	}

  
  	generation = card->generation;

  	root_node = card->root_node;
  	fw_node_get(root_node);

  	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;

  
  	irm_device = card->irm_node->data;
  	irm_is_1394_1995_only = irm_device && irm_device->config_rom &&
  			(irm_device->config_rom[2] & 0x000000f0) == 0;

  	/* Canon MV5i works unreliably if it is not root node. */
  	keep_this_irm = irm_device && irm_device->config_rom &&
  			irm_device->config_rom[3] >> 8 == CANON_OUI;

  	root_id  = root_node->node_id;
  	irm_id   = card->irm_node->node_id;
  	local_id = card->local_node->node_id;

  	grace = time_after64(get_jiffies_64(),
  			     card->reset_jiffies + DIV_ROUND_UP(HZ, 8));

  	if ((is_next_generation(generation, card->bm_generation) &&
  	     !card->bm_abdicate) ||

  	    (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.
  		 */

  		if (!card->irm_node->link_on) {
  			new_root_id = local_id;

  			fw_notify("%s, making local node (%02x) root.
  ",
  				  "IRM has link off", new_root_id);
  			goto pick_me;
  		}

  		if (irm_is_1394_1995_only && !keep_this_irm) {

  			new_root_id = local_id;
  			fw_notify("%s, making local node (%02x) root.
  ",
  				  "IRM is not 1394a compliant", new_root_id);

  			goto pick_me;
  		}

  		transaction_data[0] = cpu_to_be32(0x3f);
  		transaction_data[1] = cpu_to_be32(local_id);

  		spin_unlock_irq(&card->lock);

  		rcode = fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
  				irm_id, generation, SCODE_100,
  				CSR_REGISTER_BASE + CSR_BUS_MANAGER_ID,

  				transaction_data, 8);

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

  			goto out;

  		bm_id = be32_to_cpu(transaction_data[0]);

  		spin_lock_irq(&card->lock);
  		if (rcode == RCODE_COMPLETE && generation == card->generation)
  			card->bm_node_id =
  			    bm_id == 0x3f ? local_id : 0xffc0 | bm_id;
  		spin_unlock_irq(&card->lock);

  		if (rcode == RCODE_COMPLETE && bm_id != 0x3f) {

  			/* Somebody else is BM.  Only act as IRM. */
  			if (local_id == irm_id)
  				allocate_broadcast_channel(card, generation);

  			goto out;

  		}

  		if (rcode == RCODE_SEND_ERROR) {
  			/*
  			 * We have been unable to send the lock request due to
  			 * some local problem.  Let's try again later and hope
  			 * that the problem has gone away by then.
  			 */
  			fw_schedule_bm_work(card, DIV_ROUND_UP(HZ, 8));
  			goto out;
  		}

  		spin_lock_irq(&card->lock);

  		if (rcode != RCODE_COMPLETE && !keep_this_irm) {

  			/*
  			 * 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_id;

  			fw_notify("%s, making local node (%02x) root.
  ",
  				  "BM lock failed", new_root_id);

  			goto pick_me;
  		}
  	} else if (card->bm_generation != generation) {

  		/*

  		 * We weren't BM in the last generation, and the last
  		 * bus reset is less than 125ms ago.  Reschedule this job.

  		 */

  		spin_unlock_irq(&card->lock);

  		fw_schedule_bm_work(card, DIV_ROUND_UP(HZ, 8));

  		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_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_irq(&card->lock);

  		goto out;

  	} else if (root_device_is_cmc) {

  		/*

  		 * We will send out a force root packet for this
  		 * node as part of the gap count optimization.

  		 */

  		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_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_irq(&card->lock);

  	if (do_reset) {
  		fw_notify("phy config: card %d, new root=%x, gap_count=%d
  ",

  			  card->index, new_root_id, gap_count);
  		fw_send_phy_config(card, new_root_id, generation, gap_count);

  		reset_bus(card, true);

  		/* Will allocate broadcast channel after the reset. */

  		goto out;

  	}

  	if (root_device_is_cmc) {
  		/*
  		 * Make sure that the cycle master sends cycle start packets.
  		 */

  		transaction_data[0] = cpu_to_be32(CSR_STATE_BIT_CMSTR);

  		rcode = fw_run_transaction(card, TCODE_WRITE_QUADLET_REQUEST,
  				root_id, generation, SCODE_100,
  				CSR_REGISTER_BASE + CSR_STATE_SET,

  				transaction_data, 4);

  		if (rcode == RCODE_GENERATION)
  			goto out;

  	}

  	if (local_id == irm_id)
  		allocate_broadcast_channel(card, generation);

   out:

  	fw_node_put(root_node);

   out_put_card:
  	fw_card_put(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->split_timeout_hi = DEFAULT_SPLIT_TIMEOUT / 8000;
  	card->split_timeout_lo = (DEFAULT_SPLIT_TIMEOUT % 8000) << 19;
  	card->split_timeout_cycles = DEFAULT_SPLIT_TIMEOUT;
  	card->split_timeout_jiffies =
  			DIV_ROUND_UP(DEFAULT_SPLIT_TIMEOUT * HZ, 8000);

  	card->color = 0;

  	card->broadcast_channel = BROADCAST_CHANNEL_INITIAL;

  	kref_init(&card->kref);
  	init_completion(&card->done);

  	INIT_LIST_HEAD(&card->transaction_list);

  	INIT_LIST_HEAD(&card->phy_receiver_list);

  	spin_lock_init(&card->lock);

  
  	card->local_node = NULL;

  	INIT_DELAYED_WORK(&card->br_work, br_work);
  	INIT_DELAYED_WORK(&card->bm_work, bm_work);

  }
  EXPORT_SYMBOL(fw_card_initialize);

  int fw_card_add(struct fw_card *card,
  		u32 max_receive, u32 link_speed, u64 guid)

  {

  	int ret;

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

  	mutex_lock(&card_mutex);

  	generate_config_rom(card, tmp_config_rom);
  	ret = card->driver->enable(card, tmp_config_rom, config_rom_length);

  	if (ret == 0)
  		list_add_tail(&card->link, &card_list);
  
  	mutex_unlock(&card_mutex);

  
  	return ret;

  }
  EXPORT_SYMBOL(fw_card_add);

  /*

   * The next few functions implement a dummy driver that is used 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 (and failed) by the dummy driver
   * instead of calling into the module.  Only functions for iso context
   * shutdown still need to be provided by the card driver.

   *
   * .read/write_csr() should never be called anymore after the dummy driver
   * was bound since they are only used within request handler context.
   * .set_config_rom() is never called since the card is taken out of card_list
   * before switching to the dummy driver.

   */

  static int dummy_read_phy_reg(struct fw_card *card, int address)

  {

  	return -ENODEV;

  }

  static int dummy_update_phy_reg(struct fw_card *card, int address,
  				int clear_bits, int set_bits)

  {
  	return -ENODEV;
  }

  static void dummy_send_request(struct fw_card *card, struct fw_packet *packet)

  {

  	packet->callback(packet, card, RCODE_CANCELLED);

  }

  static void dummy_send_response(struct fw_card *card, struct fw_packet *packet)

  {

  	packet->callback(packet, card, RCODE_CANCELLED);

  }

  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_iso_context *dummy_allocate_iso_context(struct fw_card *card,
  				int type, int channel, size_t header_size)
  {
  	return ERR_PTR(-ENODEV);
  }
  
  static int dummy_start_iso(struct fw_iso_context *ctx,
  			   s32 cycle, u32 sync, u32 tags)
  {
  	return -ENODEV;
  }
  
  static int dummy_set_iso_channels(struct fw_iso_context *ctx, u64 *channels)
  {
  	return -ENODEV;
  }
  
  static int dummy_queue_iso(struct fw_iso_context *ctx, struct fw_iso_packet *p,
  			   struct fw_iso_buffer *buffer, unsigned long payload)
  {
  	return -ENODEV;
  }

  static void dummy_flush_queue_iso(struct fw_iso_context *ctx)
  {
  }

  static const struct fw_card_driver dummy_driver_template = {

  	.read_phy_reg		= dummy_read_phy_reg,
  	.update_phy_reg		= dummy_update_phy_reg,
  	.send_request		= dummy_send_request,
  	.send_response		= dummy_send_response,
  	.cancel_packet		= dummy_cancel_packet,
  	.enable_phys_dma	= dummy_enable_phys_dma,
  	.allocate_iso_context	= dummy_allocate_iso_context,
  	.start_iso		= dummy_start_iso,
  	.set_iso_channels	= dummy_set_iso_channels,
  	.queue_iso		= dummy_queue_iso,

  	.flush_queue_iso	= dummy_flush_queue_iso,

  };

  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)

  {

  	struct fw_card_driver dummy_driver = dummy_driver_template;

  	card->driver->update_phy_reg(card, 4,
  				     PHY_LINK_ACTIVE | PHY_CONTENDER, 0);

  	fw_schedule_bus_reset(card, false, true);

  	mutex_lock(&card_mutex);

  	list_del_init(&card->link);

  	mutex_unlock(&card_mutex);

  	/* Switch off most of the card driver interface. */
  	dummy_driver.free_iso_context	= card->driver->free_iso_context;
  	dummy_driver.stop_iso		= card->driver->stop_iso;

  	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));

  }
  EXPORT_SYMBOL(fw_core_remove_card);