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/*

 * 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);