sas_discover.c

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/*
 * Serial Attached SCSI (SAS) Discover process
 *
 * Copyright (C) 2005 Adaptec, Inc.  All rights reserved.
 * Copyright (C) 2005 Luben Tuikov <[email protected]>
 *
 * This file is licensed under GPLv2.
 *
 * 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

#include <linux/scatterlist.h>
#include <linux/slab.h>
#include <linux/async.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_eh.h>
#include "sas_internal.h"

#include <scsi/scsi_transport.h>
#include <scsi/scsi_transport_sas.h>
#include <scsi/sas_ata.h>
#include "../scsi_sas_internal.h"

/* ---------- Basic task processing for discovery purposes ---------- */

void sas_init_dev(struct domain_device *dev)
{
    switch (dev->dev_type) {
    case SAS_END_DEV:
        INIT_LIST_HEAD(&dev->ssp_dev.eh_list_node);
        break;
    case EDGE_DEV:
    case FANOUT_DEV:
        INIT_LIST_HEAD(&dev->ex_dev.children);
        mutex_init(&dev->ex_dev.cmd_mutex);
        break;
    default:
        break;
    }
}

/* ---------- Domain device discovery ---------- */

static int sas_get_port_device(struct asd_sas_port *port)
{
    struct asd_sas_phy *phy;
    struct sas_rphy *rphy;
    struct domain_device *dev;
    int rc = -ENODEV;

    dev = sas_alloc_device();
    if (!dev)
        return -ENOMEM;

    spin_lock_irq(&port->phy_list_lock);
    if (list_empty(&port->phy_list)) {
        spin_unlock_irq(&port->phy_list_lock);
        sas_put_device(dev);
        return -ENODEV;
    }
    phy = container_of(port->phy_list.next, struct asd_sas_phy, port_phy_el);
    spin_lock(&phy->frame_rcvd_lock);
    memcpy(dev->frame_rcvd, phy->frame_rcvd, min(sizeof(dev->frame_rcvd),
                         (size_t)phy->frame_rcvd_size));
    spin_unlock(&phy->frame_rcvd_lock);
    spin_unlock_irq(&port->phy_list_lock);

    if (dev->frame_rcvd[0] == 0x34 && port->oob_mode == SATA_OOB_MODE) {
        struct dev_to_host_fis *fis =
            (struct dev_to_host_fis *) dev->frame_rcvd;
        if (fis->interrupt_reason == 1 && fis->lbal == 1 &&
            fis->byte_count_low==0x69 && fis->byte_count_high == 0x96
            && (fis->device & ~0x10) == 0)
            dev->dev_type = SATA_PM;
        else
            dev->dev_type = SATA_DEV;
        dev->tproto = SAS_PROTOCOL_SATA;
    } else {
        struct sas_identify_frame *id =
            (struct sas_identify_frame *) dev->frame_rcvd;
        dev->dev_type = id->dev_type;
        dev->iproto = id->initiator_bits;
        dev->tproto = id->target_bits;
    }

    sas_init_dev(dev);

    dev->port = port;
    switch (dev->dev_type) {
    case SATA_DEV:
        rc = sas_ata_init(dev);
        if (rc) {
            rphy = NULL;
            break;
        }
        /* fall through */
    case SAS_END_DEV:
        rphy = sas_end_device_alloc(port->port);
        break;
    case EDGE_DEV:
        rphy = sas_expander_alloc(port->port,
                      SAS_EDGE_EXPANDER_DEVICE);
        break;
    case FANOUT_DEV:
        rphy = sas_expander_alloc(port->port,
                      SAS_FANOUT_EXPANDER_DEVICE);
        break;
    default:
        printk("ERROR: Unidentified device type %d\n", dev->dev_type);
        rphy = NULL;
        break;
    }

    if (!rphy) {
        sas_put_device(dev);
        return rc;
    }

    rphy->identify.phy_identifier = phy->phy->identify.phy_identifier;
    memcpy(dev->sas_addr, port->attached_sas_addr, SAS_ADDR_SIZE);
    sas_fill_in_rphy(dev, rphy);
    sas_hash_addr(dev->hashed_sas_addr, dev->sas_addr);
    port->port_dev = dev;
    dev->linkrate = port->linkrate;
    dev->min_linkrate = port->linkrate;
    dev->max_linkrate = port->linkrate;
    dev->pathways = port->num_phys;
    memset(port->disc.fanout_sas_addr, 0, SAS_ADDR_SIZE);
    memset(port->disc.eeds_a, 0, SAS_ADDR_SIZE);
    memset(port->disc.eeds_b, 0, SAS_ADDR_SIZE);
    port->disc.max_level = 0;
    sas_device_set_phy(dev, port->port);

    dev->rphy = rphy;
    get_device(&dev->rphy->dev);

    if (dev_is_sata(dev) || dev->dev_type == SAS_END_DEV)
        list_add_tail(&dev->disco_list_node, &port->disco_list);
    else {
        spin_lock_irq(&port->dev_list_lock);
        list_add_tail(&dev->dev_list_node, &port->dev_list);
        spin_unlock_irq(&port->dev_list_lock);
    }

    spin_lock_irq(&port->phy_list_lock);
    list_for_each_entry(phy, &port->phy_list, port_phy_el)
        sas_phy_set_target(phy, dev);
    spin_unlock_irq(&port->phy_list_lock);

    return 0;
}

/* ---------- Discover and Revalidate ---------- */

int sas_notify_lldd_dev_found(struct domain_device *dev)
{
    int res = 0;
    struct sas_ha_struct *sas_ha = dev->port->ha;
    struct Scsi_Host *shost = sas_ha->core.shost;
    struct sas_internal *i = to_sas_internal(shost->transportt);

    if (!i->dft->lldd_dev_found)
        return 0;

    res = i->dft->lldd_dev_found(dev);
    if (res) {
        printk("sas: driver on pcidev %s cannot handle "
               "device %llx, error:%d\n",
               dev_name(sas_ha->dev),
               SAS_ADDR(dev->sas_addr), res);
    }
    set_bit(SAS_DEV_FOUND, &dev->state);
    kref_get(&dev->kref);
    return res;
}


void sas_notify_lldd_dev_gone(struct domain_device *dev)
{
    struct sas_ha_struct *sas_ha = dev->port->ha;
    struct Scsi_Host *shost = sas_ha->core.shost;
    struct sas_internal *i = to_sas_internal(shost->transportt);

    if (!i->dft->lldd_dev_gone)
        return;

    if (test_and_clear_bit(SAS_DEV_FOUND, &dev->state)) {
        i->dft->lldd_dev_gone(dev);
        sas_put_device(dev);
    }
}

static void sas_probe_devices(struct work_struct *work)
{
    struct domain_device *dev, *n;
    struct sas_discovery_event *ev = to_sas_discovery_event(work);
    struct asd_sas_port *port = ev->port;

    clear_bit(DISCE_PROBE, &port->disc.pending);

    /* devices must be domain members before link recovery and probe */
    list_for_each_entry(dev, &port->disco_list, disco_list_node) {
        spin_lock_irq(&port->dev_list_lock);
        list_add_tail(&dev->dev_list_node, &port->dev_list);
        spin_unlock_irq(&port->dev_list_lock);
    }

    sas_probe_sata(port);

    list_for_each_entry_safe(dev, n, &port->disco_list, disco_list_node) {
        int err;

        err = sas_rphy_add(dev->rphy);
        if (err)
            sas_fail_probe(dev, __func__, err);
        else
            list_del_init(&dev->disco_list_node);
    }
}

static void sas_suspend_devices(struct work_struct *work)
{
    struct asd_sas_phy *phy;
    struct domain_device *dev;
    struct sas_discovery_event *ev = to_sas_discovery_event(work);
    struct asd_sas_port *port = ev->port;
    struct Scsi_Host *shost = port->ha->core.shost;
    struct sas_internal *si = to_sas_internal(shost->transportt);

    clear_bit(DISCE_SUSPEND, &port->disc.pending);

    sas_suspend_sata(port);

    /* lldd is free to forget the domain_device across the
     * suspension, we force the issue here to keep the reference
     * counts aligned
     */
    list_for_each_entry(dev, &port->dev_list, dev_list_node)
        sas_notify_lldd_dev_gone(dev);

    /* we are suspending, so we know events are disabled and
     * phy_list is not being mutated
     */
    list_for_each_entry(phy, &port->phy_list, port_phy_el) {
        if (si->dft->lldd_port_formed)
            si->dft->lldd_port_deformed(phy);
        phy->suspended = 1;
        port->suspended = 1;
    }
}

static void sas_resume_devices(struct work_struct *work)
{
    struct sas_discovery_event *ev = to_sas_discovery_event(work);
    struct asd_sas_port *port = ev->port;

    clear_bit(DISCE_RESUME, &port->disc.pending);

    sas_resume_sata(port);
}

int sas_discover_end_dev(struct domain_device *dev)
{
    int res;

    res = sas_notify_lldd_dev_found(dev);
    if (res)
        return res;
    sas_discover_event(dev->port, DISCE_PROBE);

    return 0;
}

/* ---------- Device registration and unregistration ---------- */

void sas_free_device(struct kref *kref)
{
    struct domain_device *dev = container_of(kref, typeof(*dev), kref);

    put_device(&dev->rphy->dev);
    dev->rphy = NULL;

    if (dev->parent)
        sas_put_device(dev->parent);

    sas_port_put_phy(dev->phy);
    dev->phy = NULL;

    /* remove the phys and ports, everything else should be gone */
    if (dev->dev_type == EDGE_DEV || dev->dev_type == FANOUT_DEV)
        kfree(dev->ex_dev.ex_phy);

    if (dev_is_sata(dev) && dev->sata_dev.ap) {
        ata_sas_port_destroy(dev->sata_dev.ap);
        dev->sata_dev.ap = NULL;
    }

    kfree(dev);
}

static void sas_unregister_common_dev(struct asd_sas_port *port, struct domain_device *dev)
{
    struct sas_ha_struct *ha = port->ha;

    sas_notify_lldd_dev_gone(dev);
    if (!dev->parent)
        dev->port->port_dev = NULL;
    else
        list_del_init(&dev->siblings);

    spin_lock_irq(&port->dev_list_lock);
    list_del_init(&dev->dev_list_node);
    if (dev_is_sata(dev))
        sas_ata_end_eh(dev->sata_dev.ap);
    spin_unlock_irq(&port->dev_list_lock);

    spin_lock_irq(&ha->lock);
    if (dev->dev_type == SAS_END_DEV &&
        !list_empty(&dev->ssp_dev.eh_list_node)) {
        list_del_init(&dev->ssp_dev.eh_list_node);
        ha->eh_active--;
    }
    spin_unlock_irq(&ha->lock);

    sas_put_device(dev);
}

static void sas_destruct_devices(struct work_struct *work)
{
    struct domain_device *dev, *n;
    struct sas_discovery_event *ev = to_sas_discovery_event(work);
    struct asd_sas_port *port = ev->port;

    clear_bit(DISCE_DESTRUCT, &port->disc.pending);

    list_for_each_entry_safe(dev, n, &port->destroy_list, disco_list_node) {
        list_del_init(&dev->disco_list_node);

        sas_remove_children(&dev->rphy->dev);
        sas_rphy_delete(dev->rphy);
        sas_unregister_common_dev(port, dev);
    }
}

void sas_unregister_dev(struct asd_sas_port *port, struct domain_device *dev)
{
    if (!test_bit(SAS_DEV_DESTROY, &dev->state) &&
        !list_empty(&dev->disco_list_node)) {
        /* this rphy never saw sas_rphy_add */
        list_del_init(&dev->disco_list_node);
        sas_rphy_free(dev->rphy);
        sas_unregister_common_dev(port, dev);
        return;
    }

    if (!test_and_set_bit(SAS_DEV_DESTROY, &dev->state)) {
        sas_rphy_unlink(dev->rphy);
        list_move_tail(&dev->disco_list_node, &port->destroy_list);
        sas_discover_event(dev->port, DISCE_DESTRUCT);
    }
}

void sas_unregister_domain_devices(struct asd_sas_port *port, int gone)
{
    struct domain_device *dev, *n;

    list_for_each_entry_safe_reverse(dev, n, &port->dev_list, dev_list_node) {
        if (gone)
            set_bit(SAS_DEV_GONE, &dev->state);
        sas_unregister_dev(port, dev);
    }

    list_for_each_entry_safe(dev, n, &port->disco_list, disco_list_node)
        sas_unregister_dev(port, dev);

    port->port->rphy = NULL;

}

void sas_device_set_phy(struct domain_device *dev, struct sas_port *port)
{
    struct sas_ha_struct *ha;
    struct sas_phy *new_phy;

    if (!dev)
        return;

    ha = dev->port->ha;
    new_phy = sas_port_get_phy(port);

    /* pin and record last seen phy */
    spin_lock_irq(&ha->phy_port_lock);
    if (new_phy) {
        sas_port_put_phy(dev->phy);
        dev->phy = new_phy;
    }
    spin_unlock_irq(&ha->phy_port_lock);
}

/* ---------- Discovery and Revalidation ---------- */

static void sas_discover_domain(struct work_struct *work)
{
    struct domain_device *dev;
    int error = 0;
    struct sas_discovery_event *ev = to_sas_discovery_event(work);
    struct asd_sas_port *port = ev->port;

    clear_bit(DISCE_DISCOVER_DOMAIN, &port->disc.pending);

    if (port->port_dev)
        return;

    error = sas_get_port_device(port);
    if (error)
        return;
    dev = port->port_dev;

    SAS_DPRINTK("DOING DISCOVERY on port %d, pid:%d\n", port->id,
            task_pid_nr(current));

    switch (dev->dev_type) {
    case SAS_END_DEV:
        error = sas_discover_end_dev(dev);
        break;
    case EDGE_DEV:
    case FANOUT_DEV:
        error = sas_discover_root_expander(dev);
        break;
    case SATA_DEV:
    case SATA_PM:
#ifdef CONFIG_SCSI_SAS_ATA
        error = sas_discover_sata(dev);
        break;
#else
        SAS_DPRINTK("ATA device seen but CONFIG_SCSI_SAS_ATA=N so cannot attach\n");
        /* Fall through */
#endif
    default:
        error = -ENXIO;
        SAS_DPRINTK("unhandled device %d\n", dev->dev_type);
        break;
    }

    if (error) {
        sas_rphy_free(dev->rphy);
        list_del_init(&dev->disco_list_node);
        spin_lock_irq(&port->dev_list_lock);
        list_del_init(&dev->dev_list_node);
        spin_unlock_irq(&port->dev_list_lock);

        sas_put_device(dev);
        port->port_dev = NULL;
    }

    SAS_DPRINTK("DONE DISCOVERY on port %d, pid:%d, result:%d\n", port->id,
            task_pid_nr(current), error);
}

static void sas_revalidate_domain(struct work_struct *work)
{
    int res = 0;
    struct sas_discovery_event *ev = to_sas_discovery_event(work);
    struct asd_sas_port *port = ev->port;
    struct sas_ha_struct *ha = port->ha;

    /* prevent revalidation from finding sata links in recovery */
    mutex_lock(&ha->disco_mutex);
    if (test_bit(SAS_HA_ATA_EH_ACTIVE, &ha->state)) {
        SAS_DPRINTK("REVALIDATION DEFERRED on port %d, pid:%d\n",
                port->id, task_pid_nr(current));
        goto out;
    }

    clear_bit(DISCE_REVALIDATE_DOMAIN, &port->disc.pending);

    SAS_DPRINTK("REVALIDATING DOMAIN on port %d, pid:%d\n", port->id,
            task_pid_nr(current));

    if (port->port_dev)
        res = sas_ex_revalidate_domain(port->port_dev);

    SAS_DPRINTK("done REVALIDATING DOMAIN on port %d, pid:%d, res 0x%x\n",
            port->id, task_pid_nr(current), res);
 out:
    mutex_unlock(&ha->disco_mutex);
}

/* ---------- Events ---------- */

static void sas_chain_work(struct sas_ha_struct *ha, struct sas_work *sw)
{
    /* chained work is not subject to SA_HA_DRAINING or
     * SAS_HA_REGISTERED, because it is either submitted in the
     * workqueue, or known to be submitted from a context that is
     * not racing against draining
     */
    scsi_queue_work(ha->core.shost, &sw->work);
}

static void sas_chain_event(int event, unsigned long *pending,
                struct sas_work *sw,
                struct sas_ha_struct *ha)
{
    if (!test_and_set_bit(event, pending)) {
        unsigned long flags;

        spin_lock_irqsave(&ha->lock, flags);
        sas_chain_work(ha, sw);
        spin_unlock_irqrestore(&ha->lock, flags);
    }
}

int sas_discover_event(struct asd_sas_port *port, enum discover_event ev)
{
    struct sas_discovery *disc;

    if (!port)
        return 0;
    disc = &port->disc;

    BUG_ON(ev >= DISC_NUM_EVENTS);

    sas_chain_event(ev, &disc->pending, &disc->disc_work[ev].work, port->ha);

    return 0;
}

void sas_init_disc(struct sas_discovery *disc, struct asd_sas_port *port)
{
    int i;

    static const work_func_t sas_event_fns[DISC_NUM_EVENTS] = {
        [DISCE_DISCOVER_DOMAIN] = sas_discover_domain,
        [DISCE_REVALIDATE_DOMAIN] = sas_revalidate_domain,
        [DISCE_PROBE] = sas_probe_devices,
        [DISCE_SUSPEND] = sas_suspend_devices,
        [DISCE_RESUME] = sas_resume_devices,
        [DISCE_DESTRUCT] = sas_destruct_devices,
    };

    disc->pending = 0;
    for (i = 0; i < DISC_NUM_EVENTS; i++) {
        INIT_SAS_WORK(&disc->disc_work[i].work, sas_event_fns[i]);
        disc->disc_work[i].port = port;
    }
}