core-card.c

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/*
 * Copyright (C) 2005-2007  Kristian Hoegsberg <[email protected]>
 *
 * 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"

#define define_fw_printk_level(func, kern_level)        \
void func(const struct fw_card *card, const char *fmt, ...) \
{                               \
    struct va_format vaf;                   \
    va_list args;                       \
                                \
    va_start(args, fmt);                    \
    vaf.fmt = fmt;                      \
    vaf.va = &args;                     \
    printk(kern_level KBUILD_MODNAME " %s: %pV",        \
           dev_name(card->device), &vaf);           \
    va_end(args);                       \
}
define_fw_printk_level(fw_err, KERN_ERR);
define_fw_printk_level(fw_notice, KERN_NOTICE);

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_notice(card, "failed to allocate broadcast channel\n");
            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_notice(card, "%s, making local node (%02x) root\n",
                  "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_notice(card, "%s, making local node (%02x) root\n",
                  "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_notice(card, "BM lock failed (%s), making local node (%02x) root\n",
                  fw_rcode_string(rcode), 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_notice(card, "phy config: new root=%x, gap_count=%d\n",
              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 int dummy_flush_iso_completions(struct fw_iso_context *ctx)
{
    return -ENODEV;
}

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,
    .flush_iso_completions  = dummy_flush_iso_completions,
};

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

    complete(&card->done);
}
EXPORT_SYMBOL_GPL(fw_card_release);

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);