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fw-card.c

/*
 * 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/module.h>
#include <linux/errno.h>
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/crc-itu-t.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 mathces
       * 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;
}
EXPORT_SYMBOL(fw_core_add_descriptor);

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);
}
EXPORT_SYMBOL(fw_core_remove_descriptor);

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

struct bm_data {
      struct fw_transaction t;
      struct {
            __be32 arg;
            __be32 data;
      } lock;
      u32 old;
      int rcode;
      struct completion done;
};

static void
complete_bm_lock(struct fw_card *card, int rcode,
             void *payload, size_t length, void *data)
{
      struct bm_data *bmd = data;

      if (rcode == RCODE_COMPLETE)
            bmd->old = be32_to_cpu(*(__be32 *) payload);
      bmd->rcode = rcode;
      complete(&bmd->done);
}

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;
      struct bm_data bmd;
      unsigned long flags;
      int root_id, new_root_id, irm_id, gap_count, generation, grace;
      int do_reset = 0;

      spin_lock_irqsave(&card->lock, flags);

      generation = card->generation;
      root = card->root_node->data;
      root_id = card->root_node->node_id;
      grace = time_after(jiffies, card->reset_jiffies + DIV_ROUND_UP(HZ, 10));

      if (card->bm_generation + 1 == 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 = card->local_node->node_id;
                  fw_notify("IRM has link off, making local node (%02x) root.\n",
                          new_root_id);
                  goto pick_me;
            }

            bmd.lock.arg = cpu_to_be32(0x3f);
            bmd.lock.data = cpu_to_be32(card->local_node->node_id);

            spin_unlock_irqrestore(&card->lock, flags);

            init_completion(&bmd.done);
            fw_send_request(card, &bmd.t, TCODE_LOCK_COMPARE_SWAP,
                        irm_id, generation,
                        SCODE_100, CSR_REGISTER_BASE + CSR_BUS_MANAGER_ID,
                        &bmd.lock, sizeof(bmd.lock),
                        complete_bm_lock, &bmd);
            wait_for_completion(&bmd.done);

            if (bmd.rcode == RCODE_GENERATION) {
                  /*
                   * Another bus reset happened. Just return,
                   * the BM work has been rescheduled.
                   */
                  return;
            }

            if (bmd.rcode == RCODE_COMPLETE && bmd.old != 0x3f)
                  /* Somebody else is BM, let them do the work. */
                  return;

            spin_lock_irqsave(&card->lock, flags);
            if (bmd.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 = card->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);
            schedule_delayed_work(&card->work, DIV_ROUND_UP(HZ, 10));
            return;
      }

      /*
       * 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 == NULL) {
            /*
             * Either link_on is false, or we failed to read the
             * config rom.  In either case, pick another root.
             */
            new_root_id = card->local_node->node_id;
      } else if (atomic_read(&root->state) != FW_DEVICE_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);
            return;
      } else if (root->config_rom[2] & BIB_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 = card->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 &&
          card->root_node->max_hops < ARRAY_SIZE(gap_count_table))
            gap_count = gap_count_table[card->root_node->max_hops];
      else
            gap_count = 63;

      /*
       * Finally, figure out if we should do a reset or not.  If we've
       * done less that 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 = 1;

      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);
      }
}

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);

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

      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;

      /*
       * The subsystem grabs a reference when the card is added and
       * drops it when the driver calls fw_core_remove_card.
       */
      fw_card_get(card);

      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 = {
      .name            = "dummy",
      .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_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(&card->link);
      mutex_unlock(&card_mutex);

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

      fw_destroy_nodes(card);
      flush_scheduled_work();

      fw_flush_transactions(card);
      del_timer_sync(&card->flush_timer);

      fw_card_put(card);
}
EXPORT_SYMBOL(fw_core_remove_card);

struct fw_card *
fw_card_get(struct fw_card *card)
{
      kref_get(&card->kref);

      return card;
}
EXPORT_SYMBOL(fw_card_get);

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

      kfree(card);
}

/*
 * An assumption for fw_card_put() is that the card driver allocates
 * the fw_card struct with kalloc and that it has been shut down
 * before the last ref is dropped.
 */
void
fw_card_put(struct fw_card *card)
{
      kref_put(&card->kref, release_card);
}
EXPORT_SYMBOL(fw_card_put);

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);

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