// SPDX-License-Identifier: GPL-2.0
/*
 * Serial Attached SCSI (SAS) Expander discovery and configuration
 *
 * Copyright (C) 2005 Adaptec, Inc.  All rights reserved.
 * Copyright (C) 2005 Luben Tuikov <luben_tuikov@adaptec.com>
 *
 * This file is licensed under GPLv2.
 */

#include <linux/scatterlist.h>
#include <linux/blkdev.h>
#include <linux/slab.h>
#include <asm/unaligned.h>

#include "sas_internal.h"

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

static int sas_discover_expander(struct domain_device *dev);
static int sas_configure_routing(struct domain_device *dev, u8 *sas_addr);
static int sas_configure_phy(struct domain_device *dev, int phy_id,
                             u8 *sas_addr, int include);
static int sas_disable_routing(struct domain_device *dev,  u8 *sas_addr);

/* ---------- SMP task management ---------- */

static void smp_task_timedout(struct timer_list *t)
{
        struct sas_task_slow *slow = from_timer(slow, t, timer);
        struct sas_task *task = slow->task;
        unsigned long flags;

        spin_lock_irqsave(&task->task_state_lock, flags);
        if (!(task->task_state_flags & SAS_TASK_STATE_DONE)) {
                task->task_state_flags |= SAS_TASK_STATE_ABORTED;
                complete(&task->slow_task->completion);
        }
        spin_unlock_irqrestore(&task->task_state_lock, flags);
}

static void smp_task_done(struct sas_task *task)
{
        del_timer(&task->slow_task->timer);
        complete(&task->slow_task->completion);
}

/* Give it some long enough timeout. In seconds. */
#define SMP_TIMEOUT 10

static int smp_execute_task_sg(struct domain_device *dev,
                struct scatterlist *req, struct scatterlist *resp)
{
        int res, retry;
        struct sas_task *task = NULL;
        struct sas_internal *i =
                to_sas_internal(dev->port->ha->core.shost->transportt);

        mutex_lock(&dev->ex_dev.cmd_mutex);
        for (retry = 0; retry < 3; retry++) {
                if (test_bit(SAS_DEV_GONE, &dev->state)) {
                        res = -ECOMM;
                        break;
                }

                task = sas_alloc_slow_task(GFP_KERNEL);
                if (!task) {
                        res = -ENOMEM;
                        break;
                }
                task->dev = dev;
                task->task_proto = dev->tproto;
                task->smp_task.smp_req = *req;
                task->smp_task.smp_resp = *resp;

                task->task_done = smp_task_done;

                task->slow_task->timer.function = smp_task_timedout;
                task->slow_task->timer.expires = jiffies + SMP_TIMEOUT*HZ;
                add_timer(&task->slow_task->timer);

                res = i->dft->lldd_execute_task(task, GFP_KERNEL);

                if (res) {
                        del_timer(&task->slow_task->timer);
                        pr_notice("executing SMP task failed:%d\n", res);
                        break;
                }

                wait_for_completion(&task->slow_task->completion);
                res = -ECOMM;
                if ((task->task_state_flags & SAS_TASK_STATE_ABORTED)) {
                        pr_notice("smp task timed out or aborted\n");
                        i->dft->lldd_abort_task(task);
                        if (!(task->task_state_flags & SAS_TASK_STATE_DONE)) {
                                pr_notice("SMP task aborted and not done\n");
                                break;
                        }
                }
                if (task->task_status.resp == SAS_TASK_COMPLETE &&
                    task->task_status.stat == SAS_SAM_STAT_GOOD) {
                        res = 0;
                        break;
                }
                if (task->task_status.resp == SAS_TASK_COMPLETE &&
                    task->task_status.stat == SAS_DATA_UNDERRUN) {
                        /* no error, but return the number of bytes of
                         * underrun */
                        res = task->task_status.residual;
                        break;
                }
                if (task->task_status.resp == SAS_TASK_COMPLETE &&
                    task->task_status.stat == SAS_DATA_OVERRUN) {
                        res = -EMSGSIZE;
                        break;
                }
                if (task->task_status.resp == SAS_TASK_UNDELIVERED &&
                    task->task_status.stat == SAS_DEVICE_UNKNOWN)
                        break;
                else {
                        pr_notice("%s: task to dev %016llx response: 0x%x status 0x%x\n",
                                  __func__,
                                  SAS_ADDR(dev->sas_addr),
                                  task->task_status.resp,
                                  task->task_status.stat);
                        sas_free_task(task);
                        task = NULL;
                }
        }
        mutex_unlock(&dev->ex_dev.cmd_mutex);

        BUG_ON(retry == 3 && task != NULL);
        sas_free_task(task);
        return res;
}

static int smp_execute_task(struct domain_device *dev, void *req, int req_size,
                            void *resp, int resp_size)
{
        struct scatterlist req_sg;
        struct scatterlist resp_sg;

        sg_init_one(&req_sg, req, req_size);
        sg_init_one(&resp_sg, resp, resp_size);
        return smp_execute_task_sg(dev, &req_sg, &resp_sg);
}

/* ---------- Allocations ---------- */

static inline void *alloc_smp_req(int size)
{
        u8 *p = kzalloc(size, GFP_KERNEL);
        if (p)
                p[0] = SMP_REQUEST;
        return p;
}

static inline void *alloc_smp_resp(int size)
{
        return kzalloc(size, GFP_KERNEL);
}

static char sas_route_char(struct domain_device *dev, struct ex_phy *phy)
{
        switch (phy->routing_attr) {
        case TABLE_ROUTING:
                if (dev->ex_dev.t2t_supp)
                        return 'U';
                else
                        return 'T';
        case DIRECT_ROUTING:
                return 'D';
        case SUBTRACTIVE_ROUTING:
                return 'S';
        default:
                return '?';
        }
}

static enum sas_device_type to_dev_type(struct discover_resp *dr)
{
        /* This is detecting a failure to transmit initial dev to host
         * FIS as described in section J.5 of sas-2 r16
         */
        if (dr->attached_dev_type == SAS_PHY_UNUSED && dr->attached_sata_dev &&
            dr->linkrate >= SAS_LINK_RATE_1_5_GBPS)
                return SAS_SATA_PENDING;
        else
                return dr->attached_dev_type;
}

static void sas_set_ex_phy(struct domain_device *dev, int phy_id, void *rsp)
{
        enum sas_device_type dev_type;
        enum sas_linkrate linkrate;
        u8 sas_addr[SAS_ADDR_SIZE];
        struct smp_resp *resp = rsp;
        struct discover_resp *dr = &resp->disc;
        struct sas_ha_struct *ha = dev->port->ha;
        struct expander_device *ex = &dev->ex_dev;
        struct ex_phy *phy = &ex->ex_phy[phy_id];
        struct sas_rphy *rphy = dev->rphy;
        bool new_phy = !phy->phy;
        char *type;

        if (new_phy) {
                if (WARN_ON_ONCE(test_bit(SAS_HA_ATA_EH_ACTIVE, &ha->state)))
                        return;
                phy->phy = sas_phy_alloc(&rphy->dev, phy_id);

                /* FIXME: error_handling */
                BUG_ON(!phy->phy);
        }

        switch (resp->result) {
        case SMP_RESP_PHY_VACANT:
                phy->phy_state = PHY_VACANT;
                break;
        default:
                phy->phy_state = PHY_NOT_PRESENT;
                break;
        case SMP_RESP_FUNC_ACC:
                phy->phy_state = PHY_EMPTY; /* do not know yet */
                break;
        }

        /* check if anything important changed to squelch debug */
        dev_type = phy->attached_dev_type;
        linkrate  = phy->linkrate;
        memcpy(sas_addr, phy->attached_sas_addr, SAS_ADDR_SIZE);

        /* Handle vacant phy - rest of dr data is not valid so skip it */
        if (phy->phy_state == PHY_VACANT) {
                memset(phy->attached_sas_addr, 0, SAS_ADDR_SIZE);
                phy->attached_dev_type = SAS_PHY_UNUSED;
                if (!test_bit(SAS_HA_ATA_EH_ACTIVE, &ha->state)) {
                        phy->phy_id = phy_id;
                        goto skip;
                } else
                        goto out;
        }

        phy->attached_dev_type = to_dev_type(dr);
        if (test_bit(SAS_HA_ATA_EH_ACTIVE, &ha->state))
                goto out;
        phy->phy_id = phy_id;
        phy->linkrate = dr->linkrate;
        phy->attached_sata_host = dr->attached_sata_host;
        phy->attached_sata_dev  = dr->attached_sata_dev;
        phy->attached_sata_ps   = dr->attached_sata_ps;
        phy->attached_iproto = dr->iproto << 1;
        phy->attached_tproto = dr->tproto << 1;
        /* help some expanders that fail to zero sas_address in the 'no
         * device' case
         */
        if (phy->attached_dev_type == SAS_PHY_UNUSED ||
            phy->linkrate < SAS_LINK_RATE_1_5_GBPS)
                memset(phy->attached_sas_addr, 0, SAS_ADDR_SIZE);
        else
                memcpy(phy->attached_sas_addr, dr->attached_sas_addr, SAS_ADDR_SIZE);
        phy->attached_phy_id = dr->attached_phy_id;
        phy->phy_change_count = dr->change_count;
        phy->routing_attr = dr->routing_attr;
        phy->virtual = dr->virtual;
        phy->last_da_index = -1;

        phy->phy->identify.sas_address = SAS_ADDR(phy->attached_sas_addr);
        phy->phy->identify.device_type = dr->attached_dev_type;
        phy->phy->identify.initiator_port_protocols = phy->attached_iproto;
        phy->phy->identify.target_port_protocols = phy->attached_tproto;
        if (!phy->attached_tproto && dr->attached_sata_dev)
                phy->phy->identify.target_port_protocols = SAS_PROTOCOL_SATA;
        phy->phy->identify.phy_identifier = phy_id;
        phy->phy->minimum_linkrate_hw = dr->hmin_linkrate;
        phy->phy->maximum_linkrate_hw = dr->hmax_linkrate;
        phy->phy->minimum_linkrate = dr->pmin_linkrate;
        phy->phy->maximum_linkrate = dr->pmax_linkrate;
        phy->phy->negotiated_linkrate = phy->linkrate;
        phy->phy->enabled = (phy->linkrate != SAS_PHY_DISABLED);

 skip:
        if (new_phy)
                if (sas_phy_add(phy->phy)) {
                        sas_phy_free(phy->phy);
                        return;
                }

 out:
        switch (phy->attached_dev_type) {
        case SAS_SATA_PENDING:
                type = "stp pending";
                break;
        case SAS_PHY_UNUSED:
                type = "no device";
                break;
        case SAS_END_DEVICE:
                if (phy->attached_iproto) {
                        if (phy->attached_tproto)
                                type = "host+target";
                        else
                                type = "host";
                } else {
                        if (dr->attached_sata_dev)
                                type = "stp";
                        else
                                type = "ssp";
                }
                break;
        case SAS_EDGE_EXPANDER_DEVICE:
        case SAS_FANOUT_EXPANDER_DEVICE:
                type = "smp";
                break;
        default:
                type = "unknown";
        }

        /* this routine is polled by libata error recovery so filter
         * unimportant messages
         */
        if (new_phy || phy->attached_dev_type != dev_type ||
            phy->linkrate != linkrate ||
            SAS_ADDR(phy->attached_sas_addr) != SAS_ADDR(sas_addr))
                /* pass */;
        else
                return;

        /* if the attached device type changed and ata_eh is active,
         * make sure we run revalidation when eh completes (see:
         * sas_enable_revalidation)
         */
        if (test_bit(SAS_HA_ATA_EH_ACTIVE, &ha->state))
                set_bit(DISCE_REVALIDATE_DOMAIN, &dev->port->disc.pending);

        pr_debug("%sex %016llx phy%02d:%c:%X attached: %016llx (%s)\n",
                 test_bit(SAS_HA_ATA_EH_ACTIVE, &ha->state) ? "ata: " : "",
                 SAS_ADDR(dev->sas_addr), phy->phy_id,
                 sas_route_char(dev, phy), phy->linkrate,
                 SAS_ADDR(phy->attached_sas_addr), type);
}

/* check if we have an existing attached ata device on this expander phy */
struct domain_device *sas_ex_to_ata(struct domain_device *ex_dev, int phy_id)
{
        struct ex_phy *ex_phy = &ex_dev->ex_dev.ex_phy[phy_id];
        struct domain_device *dev;
        struct sas_rphy *rphy;

        if (!ex_phy->port)
                return NULL;

        rphy = ex_phy->port->rphy;
        if (!rphy)
                return NULL;

        dev = sas_find_dev_by_rphy(rphy);

        if (dev && dev_is_sata(dev))
                return dev;

        return NULL;
}

#define DISCOVER_REQ_SIZE  16
#define DISCOVER_RESP_SIZE 56

static int sas_ex_phy_discover_helper(struct domain_device *dev, u8 *disc_req,
                                      u8 *disc_resp, int single)
{
        struct discover_resp *dr;
        int res;

        disc_req[9] = single;

        res = smp_execute_task(dev, disc_req, DISCOVER_REQ_SIZE,
                               disc_resp, DISCOVER_RESP_SIZE);
        if (res)
                return res;
        dr = &((struct smp_resp *)disc_resp)->disc;
        if (memcmp(dev->sas_addr, dr->attached_sas_addr, SAS_ADDR_SIZE) == 0) {
                pr_notice("Found loopback topology, just ignore it!\n");
                return 0;
        }
        sas_set_ex_phy(dev, single, disc_resp);
        return 0;
}

int sas_ex_phy_discover(struct domain_device *dev, int single)
{
        struct expander_device *ex = &dev->ex_dev;
        int  res = 0;
        u8   *disc_req;
        u8   *disc_resp;

        disc_req = alloc_smp_req(DISCOVER_REQ_SIZE);
        if (!disc_req)
                return -ENOMEM;

        disc_resp = alloc_smp_resp(DISCOVER_RESP_SIZE);
        if (!disc_resp) {
                kfree(disc_req);
                return -ENOMEM;
        }

        disc_req[1] = SMP_DISCOVER;

        if (0 <= single && single < ex->num_phys) {
                res = sas_ex_phy_discover_helper(dev, disc_req, disc_resp, single);
        } else {
                int i;

                for (i = 0; i < ex->num_phys; i++) {
                        res = sas_ex_phy_discover_helper(dev, disc_req,
                                                         disc_resp, i);
                        if (res)
                                goto out_err;
                }
        }
out_err:
        kfree(disc_resp);
        kfree(disc_req);
        return res;
}

static int sas_expander_discover(struct domain_device *dev)
{
        struct expander_device *ex = &dev->ex_dev;
        int res;

        ex->ex_phy = kcalloc(ex->num_phys, sizeof(*ex->ex_phy), GFP_KERNEL);
        if (!ex->ex_phy)
                return -ENOMEM;

        res = sas_ex_phy_discover(dev, -1);
        if (res)
                goto out_err;

        return 0;
 out_err:
        kfree(ex->ex_phy);
        ex->ex_phy = NULL;
        return res;
}

#define MAX_EXPANDER_PHYS 128

static void ex_assign_report_general(struct domain_device *dev,
                                            struct smp_resp *resp)
{
        struct report_general_resp *rg = &resp->rg;

        dev->ex_dev.ex_change_count = be16_to_cpu(rg->change_count);
        dev->ex_dev.max_route_indexes = be16_to_cpu(rg->route_indexes);
        dev->ex_dev.num_phys = min(rg->num_phys, (u8)MAX_EXPANDER_PHYS);
        dev->ex_dev.t2t_supp = rg->t2t_supp;
        dev->ex_dev.conf_route_table = rg->conf_route_table;
        dev->ex_dev.configuring = rg->configuring;
        memcpy(dev->ex_dev.enclosure_logical_id, rg->enclosure_logical_id, 8);
}

#define RG_REQ_SIZE   8
#define RG_RESP_SIZE 32

static int sas_ex_general(struct domain_device *dev)
{
        u8 *rg_req;
        struct smp_resp *rg_resp;
        int res;
        int i;

        rg_req = alloc_smp_req(RG_REQ_SIZE);
        if (!rg_req)
                return -ENOMEM;

        rg_resp = alloc_smp_resp(RG_RESP_SIZE);
        if (!rg_resp) {
                kfree(rg_req);
                return -ENOMEM;
        }

        rg_req[1] = SMP_REPORT_GENERAL;

        for (i = 0; i < 5; i++) {
                res = smp_execute_task(dev, rg_req, RG_REQ_SIZE, rg_resp,
                                       RG_RESP_SIZE);

                if (res) {
                        pr_notice("RG to ex %016llx failed:0x%x\n",
                                  SAS_ADDR(dev->sas_addr), res);
                        goto out;
                } else if (rg_resp->result != SMP_RESP_FUNC_ACC) {
                        pr_debug("RG:ex %016llx returned SMP result:0x%x\n",
                                 SAS_ADDR(dev->sas_addr), rg_resp->result);
                        res = rg_resp->result;
                        goto out;
                }

                ex_assign_report_general(dev, rg_resp);

                if (dev->ex_dev.configuring) {
                        pr_debug("RG: ex %016llx self-configuring...\n",
                                 SAS_ADDR(dev->sas_addr));
                        schedule_timeout_interruptible(5*HZ);
                } else
                        break;
        }
out:
        kfree(rg_req);
        kfree(rg_resp);
        return res;
}

static void ex_assign_manuf_info(struct domain_device *dev, void
                                        *_mi_resp)
{
        u8 *mi_resp = _mi_resp;
        struct sas_rphy *rphy = dev->rphy;
        struct sas_expander_device *edev = rphy_to_expander_device(rphy);

        memcpy(edev->vendor_id, mi_resp + 12, SAS_EXPANDER_VENDOR_ID_LEN);
        memcpy(edev->product_id, mi_resp + 20, SAS_EXPANDER_PRODUCT_ID_LEN);
        memcpy(edev->product_rev, mi_resp + 36,
               SAS_EXPANDER_PRODUCT_REV_LEN);

        if (mi_resp[8] & 1) {
                memcpy(edev->component_vendor_id, mi_resp + 40,
                       SAS_EXPANDER_COMPONENT_VENDOR_ID_LEN);
                edev->component_id = mi_resp[48] << 8 | mi_resp[49];
                edev->component_revision_id = mi_resp[50];
        }
}

#define MI_REQ_SIZE   8
#define MI_RESP_SIZE 64

static int sas_ex_manuf_info(struct domain_device *dev)
{
        u8 *mi_req;
        u8 *mi_resp;
        int res;

        mi_req = alloc_smp_req(MI_REQ_SIZE);
        if (!mi_req)
                return -ENOMEM;

        mi_resp = alloc_smp_resp(MI_RESP_SIZE);
        if (!mi_resp) {
                kfree(mi_req);
                return -ENOMEM;
        }

        mi_req[1] = SMP_REPORT_MANUF_INFO;

        res = smp_execute_task(dev, mi_req, MI_REQ_SIZE, mi_resp, MI_RESP_SIZE);
        if (res) {
                pr_notice("MI: ex %016llx failed:0x%x\n",
                          SAS_ADDR(dev->sas_addr), res);
                goto out;
        } else if (mi_resp[2] != SMP_RESP_FUNC_ACC) {
                pr_debug("MI ex %016llx returned SMP result:0x%x\n",
                         SAS_ADDR(dev->sas_addr), mi_resp[2]);
                goto out;
        }

        ex_assign_manuf_info(dev, mi_resp);
out:
        kfree(mi_req);
        kfree(mi_resp);
        return res;
}

#define PC_REQ_SIZE  44
#define PC_RESP_SIZE 8

int sas_smp_phy_control(struct domain_device *dev, int phy_id,
                        enum phy_func phy_func,
                        struct sas_phy_linkrates *rates)
{
        u8 *pc_req;
        u8 *pc_resp;
        int res;

        pc_req = alloc_smp_req(PC_REQ_SIZE);
        if (!pc_req)
                return -ENOMEM;

        pc_resp = alloc_smp_resp(PC_RESP_SIZE);
        if (!pc_resp) {
                kfree(pc_req);
                return -ENOMEM;
        }

        pc_req[1] = SMP_PHY_CONTROL;
        pc_req[9] = phy_id;
        pc_req[10] = phy_func;
        if (rates) {
                pc_req[32] = rates->minimum_linkrate << 4;
                pc_req[33] = rates->maximum_linkrate << 4;
        }

        res = smp_execute_task(dev, pc_req, PC_REQ_SIZE, pc_resp, PC_RESP_SIZE);
        if (res) {
                pr_err("ex %016llx phy%02d PHY control failed: %d\n",
                       SAS_ADDR(dev->sas_addr), phy_id, res);
        } else if (pc_resp[2] != SMP_RESP_FUNC_ACC) {
                pr_err("ex %016llx phy%02d PHY control failed: function result 0x%x\n",
                       SAS_ADDR(dev->sas_addr), phy_id, pc_resp[2]);
                res = pc_resp[2];
        }
        kfree(pc_resp);
        kfree(pc_req);
        return res;
}

static void sas_ex_disable_phy(struct domain_device *dev, int phy_id)
{
        struct expander_device *ex = &dev->ex_dev;
        struct ex_phy *phy = &ex->ex_phy[phy_id];

        sas_smp_phy_control(dev, phy_id, PHY_FUNC_DISABLE, NULL);
        phy->linkrate = SAS_PHY_DISABLED;
}

static void sas_ex_disable_port(struct domain_device *dev, u8 *sas_addr)
{
        struct expander_device *ex = &dev->ex_dev;
        int i;

        for (i = 0; i < ex->num_phys; i++) {
                struct ex_phy *phy = &ex->ex_phy[i];

                if (phy->phy_state == PHY_VACANT ||
                    phy->phy_state == PHY_NOT_PRESENT)
                        continue;

                if (SAS_ADDR(phy->attached_sas_addr) == SAS_ADDR(sas_addr))
                        sas_ex_disable_phy(dev, i);
        }
}

static int sas_dev_present_in_domain(struct asd_sas_port *port,
                                            u8 *sas_addr)
{
        struct domain_device *dev;

        if (SAS_ADDR(port->sas_addr) == SAS_ADDR(sas_addr))
                return 1;
        list_for_each_entry(dev, &port->dev_list, dev_list_node) {
                if (SAS_ADDR(dev->sas_addr) == SAS_ADDR(sas_addr))
                        return 1;
        }
        return 0;
}

#define RPEL_REQ_SIZE   16
#define RPEL_RESP_SIZE  32
int sas_smp_get_phy_events(struct sas_phy *phy)
{
        int res;
        u8 *req;
        u8 *resp;
        struct sas_rphy *rphy = dev_to_rphy(phy->dev.parent);
        struct domain_device *dev = sas_find_dev_by_rphy(rphy);

        req = alloc_smp_req(RPEL_REQ_SIZE);
        if (!req)
                return -ENOMEM;

        resp = alloc_smp_resp(RPEL_RESP_SIZE);
        if (!resp) {
                kfree(req);
                return -ENOMEM;
        }

        req[1] = SMP_REPORT_PHY_ERR_LOG;
        req[9] = phy->number;

        res = smp_execute_task(dev, req, RPEL_REQ_SIZE,
                               resp, RPEL_RESP_SIZE);

        if (res)
                goto out;

        phy->invalid_dword_count = get_unaligned_be32(&resp[12]);
        phy->running_disparity_error_count = get_unaligned_be32(&resp[16]);
        phy->loss_of_dword_sync_count = get_unaligned_be32(&resp[20]);
        phy->phy_reset_problem_count = get_unaligned_be32(&resp[24]);

 out:
        kfree(req);
        kfree(resp);
        return res;

}

#ifdef CONFIG_SCSI_SAS_ATA

#define RPS_REQ_SIZE  16
#define RPS_RESP_SIZE 60

int sas_get_report_phy_sata(struct domain_device *dev, int phy_id,
                            struct smp_resp *rps_resp)
{
        int res;
        u8 *rps_req = alloc_smp_req(RPS_REQ_SIZE);
        u8 *resp = (u8 *)rps_resp;

        if (!rps_req)
                return -ENOMEM;

        rps_req[1] = SMP_REPORT_PHY_SATA;
        rps_req[9] = phy_id;

        res = smp_execute_task(dev, rps_req, RPS_REQ_SIZE,
                               rps_resp, RPS_RESP_SIZE);

        /* 0x34 is the FIS type for the D2H fis.  There's a potential
         * standards cockup here.  sas-2 explicitly specifies the FIS
         * should be encoded so that FIS type is in resp[24].
         * However, some expanders endian reverse this.  Undo the
         * reversal here */
        if (!res && resp[27] == 0x34 && resp[24] != 0x34) {
                int i;

                for (i = 0; i < 5; i++) {
                        int j = 24 + (i*4);
                        u8 a, b;
                        a = resp[j + 0];
                        b = resp[j + 1];
                        resp[j + 0] = resp[j + 3];
                        resp[j + 1] = resp[j + 2];
                        resp[j + 2] = b;
                        resp[j + 3] = a;
                }
        }

        kfree(rps_req);
        return res;
}
#endif

static void sas_ex_get_linkrate(struct domain_device *parent,
                                       struct domain_device *child,
                                       struct ex_phy *parent_phy)
{
        struct expander_device *parent_ex = &parent->ex_dev;
        struct sas_port *port;
        int i;

        child->pathways = 0;

        port = parent_phy->port;

        for (i = 0; i < parent_ex->num_phys; i++) {
                struct ex_phy *phy = &parent_ex->ex_phy[i];

                if (phy->phy_state == PHY_VACANT ||
                    phy->phy_state == PHY_NOT_PRESENT)
                        continue;

                if (SAS_ADDR(phy->attached_sas_addr) ==
                    SAS_ADDR(child->sas_addr)) {

                        child->min_linkrate = min(parent->min_linkrate,
                                                  phy->linkrate);
                        child->max_linkrate = max(parent->max_linkrate,
                                                  phy->linkrate);
                        child->pathways++;
                        sas_port_add_phy(port, phy->phy);
                }
        }
        child->linkrate = min(parent_phy->linkrate, child->max_linkrate);
        child->pathways = min(child->pathways, parent->pathways);
}

static struct domain_device *sas_ex_discover_end_dev(
        struct domain_device *parent, int phy_id)
{
        struct expander_device *parent_ex = &parent->ex_dev;
        struct ex_phy *phy = &parent_ex->ex_phy[phy_id];
        struct domain_device *child = NULL;
        struct sas_rphy *rphy;
        int res;

        if (phy->attached_sata_host || phy->attached_sata_ps)
                return NULL;

        child = sas_alloc_device();
        if (!child)
                return NULL;

        kref_get(&parent->kref);
        child->parent = parent;
        child->port   = parent->port;
        child->iproto = phy->attached_iproto;
        memcpy(child->sas_addr, phy->attached_sas_addr, SAS_ADDR_SIZE);
        sas_hash_addr(child->hashed_sas_addr, child->sas_addr);
        if (!phy->port) {
                phy->port = sas_port_alloc(&parent->rphy->dev, phy_id);
                if (unlikely(!phy->port))
                        goto out_err;
                if (unlikely(sas_port_add(phy->port) != 0)) {
                        sas_port_free(phy->port);
                        goto out_err;
                }
        }
        sas_ex_get_linkrate(parent, child, phy);
        sas_device_set_phy(child, phy->port);

#ifdef CONFIG_SCSI_SAS_ATA
        if ((phy->attached_tproto & SAS_PROTOCOL_STP) || phy->attached_sata_dev) {
                if (child->linkrate > parent->min_linkrate) {
                        struct sas_phy *cphy = child->phy;
                        enum sas_linkrate min_prate = cphy->minimum_linkrate,
                                parent_min_lrate = parent->min_linkrate,
                                min_linkrate = (min_prate > parent_min_lrate) ?
                                               parent_min_lrate : 0;
                        struct sas_phy_linkrates rates = {
                                .maximum_linkrate = parent->min_linkrate,
                                .minimum_linkrate = min_linkrate,
                        };
                        int ret;

                        pr_notice("ex %016llx phy%02d SATA device linkrate > min pathway connection rate, attempting to lower device linkrate\n",
                                   SAS_ADDR(child->sas_addr), phy_id);
                        ret = sas_smp_phy_control(parent, phy_id,
                                                  PHY_FUNC_LINK_RESET, &rates);
                        if (ret) {
                                pr_err("ex %016llx phy%02d SATA device could not set linkrate (%d)\n",
                                       SAS_ADDR(child->sas_addr), phy_id, ret);
                                goto out_free;
                        }
                        pr_notice("ex %016llx phy%02d SATA device set linkrate successfully\n",
                                  SAS_ADDR(child->sas_addr), phy_id);
                        child->linkrate = child->min_linkrate;
                }
                res = sas_get_ata_info(child, phy);
                if (res)
                        goto out_free;

                sas_init_dev(child);
                res = sas_ata_init(child);
                if (res)
                        goto out_free;
                rphy = sas_end_device_alloc(phy->port);
                if (!rphy)
                        goto out_free;
                rphy->identify.phy_identifier = phy_id;

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

                list_add_tail(&child->disco_list_node, &parent->port->disco_list);

                res = sas_discover_sata(child);
                if (res) {
                        pr_notice("sas_discover_sata() for device %16llx at %016llx:%02d returned 0x%x\n",
                                  SAS_ADDR(child->sas_addr),
                                  SAS_ADDR(parent->sas_addr), phy_id, res);
                        goto out_list_del;
                }
        } else
#endif
          if (phy->attached_tproto & SAS_PROTOCOL_SSP) {
                child->dev_type = SAS_END_DEVICE;
                rphy = sas_end_device_alloc(phy->port);
                /* FIXME: error handling */
                if (unlikely(!rphy))
                        goto out_free;
                child->tproto = phy->attached_tproto;
                sas_init_dev(child);

                child->rphy = rphy;
                get_device(&rphy->dev);
                rphy->identify.phy_identifier = phy_id;
                sas_fill_in_rphy(child, rphy);

                list_add_tail(&child->disco_list_node, &parent->port->disco_list);

                res = sas_discover_end_dev(child);
                if (res) {
                        pr_notice("sas_discover_end_dev() for device %016llx at %016llx:%02d returned 0x%x\n",
                                  SAS_ADDR(child->sas_addr),
                                  SAS_ADDR(parent->sas_addr), phy_id, res);
                        goto out_list_del;
                }
        } else {
                pr_notice("target proto 0x%x at %016llx:0x%x not handled\n",
                          phy->attached_tproto, SAS_ADDR(parent->sas_addr),
                          phy_id);
                goto out_free;
        }

        list_add_tail(&child->siblings, &parent_ex->children);
        return child;

 out_list_del:
        sas_rphy_free(child->rphy);
        list_del(&child->disco_list_node);
        spin_lock_irq(&parent->port->dev_list_lock);
        list_del(&child->dev_list_node);
        spin_unlock_irq(&parent->port->dev_list_lock);
 out_free:
        sas_port_delete(phy->port);
 out_err:
        phy->port = NULL;
        sas_put_device(child);
        return NULL;
}

/* See if this phy is part of a wide port */
static bool sas_ex_join_wide_port(struct domain_device *parent, int phy_id)
{
        struct ex_phy *phy = &parent->ex_dev.ex_phy[phy_id];
        int i;

        for (i = 0; i < parent->ex_dev.num_phys; i++) {
                struct ex_phy *ephy = &parent->ex_dev.ex_phy[i];

                if (ephy == phy)
                        continue;

                if (!memcmp(phy->attached_sas_addr, ephy->attached_sas_addr,
                            SAS_ADDR_SIZE) && ephy->port) {
                        sas_port_add_phy(ephy->port, phy->phy);
                        phy->port = ephy->port;
                        phy->phy_state = PHY_DEVICE_DISCOVERED;
                        return true;
                }
        }

        return false;
}

static struct domain_device *sas_ex_discover_expander(
        struct domain_device *parent, int phy_id)
{
        struct sas_expander_device *parent_ex = rphy_to_expander_device(parent->rphy);
        struct ex_phy *phy = &parent->ex_dev.ex_phy[phy_id];
        struct domain_device *child = NULL;
        struct sas_rphy *rphy;
        struct sas_expander_device *edev;
        struct asd_sas_port *port;
        int res;

        if (phy->routing_attr == DIRECT_ROUTING) {
                pr_warn("ex %016llx:%02d:D <--> ex %016llx:0x%x is not allowed\n",
                        SAS_ADDR(parent->sas_addr), phy_id,
                        SAS_ADDR(phy->attached_sas_addr),
                        phy->attached_phy_id);
                return NULL;
        }
        child = sas_alloc_device();
        if (!child)
                return NULL;

        phy->port = sas_port_alloc(&parent->rphy->dev, phy_id);
        /* FIXME: better error handling */
        BUG_ON(sas_port_add(phy->port) != 0);


        switch (phy->attached_dev_type) {
        case SAS_EDGE_EXPANDER_DEVICE:
                rphy = sas_expander_alloc(phy->port,
                                          SAS_EDGE_EXPANDER_DEVICE);
                break;
        case SAS_FANOUT_EXPANDER_DEVICE:
                rphy = sas_expander_alloc(phy->port,
                                          SAS_FANOUT_EXPANDER_DEVICE);
                break;
        default:
                rphy = NULL;    /* shut gcc up */
                BUG();
        }
        port = parent->port;
        child->rphy = rphy;
        get_device(&rphy->dev);
        edev = rphy_to_expander_device(rphy);
        child->dev_type = phy->attached_dev_type;
        kref_get(&parent->kref);
        child->parent = parent;
        child->port = port;
        child->iproto = phy->attached_iproto;
        child->tproto = phy->attached_tproto;
        memcpy(child->sas_addr, phy->attached_sas_addr, SAS_ADDR_SIZE);
        sas_hash_addr(child->hashed_sas_addr, child->sas_addr);
        sas_ex_get_linkrate(parent, child, phy);
        edev->level = parent_ex->level + 1;
        parent->port->disc.max_level = max(parent->port->disc.max_level,
                                           edev->level);
        sas_init_dev(child);
        sas_fill_in_rphy(child, rphy);
        sas_rphy_add(rphy);

        spin_lock_irq(&parent->port->dev_list_lock);
        list_add_tail(&child->dev_list_node, &parent->port->dev_list);
        spin_unlock_irq(&parent->port->dev_list_lock);

        res = sas_discover_expander(child);
        if (res) {
                sas_rphy_delete(rphy);
                spin_lock_irq(&parent->port->dev_list_lock);
                list_del(&child->dev_list_node);
                spin_unlock_irq(&parent->port->dev_list_lock);
                sas_put_device(child);
                sas_port_delete(phy->port);
                phy->port = NULL;
                return NULL;
        }
        list_add_tail(&child->siblings, &parent->ex_dev.children);
        return child;
}

static int sas_ex_discover_dev(struct domain_device *dev, int phy_id)
{
        struct expander_device *ex = &dev->ex_dev;
        struct ex_phy *ex_phy = &ex->ex_phy[phy_id];
        struct domain_device *child = NULL;
        int res = 0;

        /* Phy state */
        if (ex_phy->linkrate == SAS_SATA_SPINUP_HOLD) {
                if (!sas_smp_phy_control(dev, phy_id, PHY_FUNC_LINK_RESET, NULL))
                        res = sas_ex_phy_discover(dev, phy_id);
                if (res)
                        return res;
        }

        /* Parent and domain coherency */
        if (!dev->parent && (SAS_ADDR(ex_phy->attached_sas_addr) ==
                             SAS_ADDR(dev->port->sas_addr))) {
                sas_add_parent_port(dev, phy_id);
                return 0;
        }
        if (dev->parent && (SAS_ADDR(ex_phy->attached_sas_addr) ==
                            SAS_ADDR(dev->parent->sas_addr))) {
                sas_add_parent_port(dev, phy_id);
                if (ex_phy->routing_attr == TABLE_ROUTING)
                        sas_configure_phy(dev, phy_id, dev->port->sas_addr, 1);
                return 0;
        }

        if (sas_dev_present_in_domain(dev->port, ex_phy->attached_sas_addr))
                sas_ex_disable_port(dev, ex_phy->attached_sas_addr);

        if (ex_phy->attached_dev_type == SAS_PHY_UNUSED) {
                if (ex_phy->routing_attr == DIRECT_ROUTING) {
                        memset(ex_phy->attached_sas_addr, 0, SAS_ADDR_SIZE);
                        sas_configure_routing(dev, ex_phy->attached_sas_addr);
                }
                return 0;
        } else if (ex_phy->linkrate == SAS_LINK_RATE_UNKNOWN)
                return 0;

        if (ex_phy->attached_dev_type != SAS_END_DEVICE &&
            ex_phy->attached_dev_type != SAS_FANOUT_EXPANDER_DEVICE &&
            ex_phy->attached_dev_type != SAS_EDGE_EXPANDER_DEVICE &&
            ex_phy->attached_dev_type != SAS_SATA_PENDING) {
                pr_warn("unknown device type(0x%x) attached to ex %016llx phy%02d\n",
                        ex_phy->attached_dev_type,
                        SAS_ADDR(dev->sas_addr),
                        phy_id);
                return 0;
        }

        res = sas_configure_routing(dev, ex_phy->attached_sas_addr);
        if (res) {
                pr_notice("configure routing for dev %016llx reported 0x%x. Forgotten\n",
                          SAS_ADDR(ex_phy->attached_sas_addr), res);
                sas_disable_routing(dev, ex_phy->attached_sas_addr);
                return res;
        }

        if (sas_ex_join_wide_port(dev, phy_id)) {
                pr_debug("Attaching ex phy%02d to wide port %016llx\n",
                         phy_id, SAS_ADDR(ex_phy->attached_sas_addr));
                return res;
        }

        switch (ex_phy->attached_dev_type) {
        case SAS_END_DEVICE:
        case SAS_SATA_PENDING:
                child = sas_ex_discover_end_dev(dev, phy_id);
                break;
        case SAS_FANOUT_EXPANDER_DEVICE:
                if (SAS_ADDR(dev->port->disc.fanout_sas_addr)) {
                        pr_debug("second fanout expander %016llx phy%02d attached to ex %016llx phy%02d\n",
                                 SAS_ADDR(ex_phy->attached_sas_addr),
                                 ex_phy->attached_phy_id,
                                 SAS_ADDR(dev->sas_addr),
                                 phy_id);
                        sas_ex_disable_phy(dev, phy_id);
                        return res;
                } else
                        memcpy(dev->port->disc.fanout_sas_addr,
                               ex_phy->attached_sas_addr, SAS_ADDR_SIZE);
                fallthrough;
        case SAS_EDGE_EXPANDER_DEVICE:
                child = sas_ex_discover_expander(dev, phy_id);
                break;
        default:
                break;
        }

        if (!child)
                pr_notice("ex %016llx phy%02d failed to discover\n",
                          SAS_ADDR(dev->sas_addr), phy_id);
        return res;
}

static int sas_find_sub_addr(struct domain_device *dev, u8 *sub_addr)
{
        struct expander_device *ex = &dev->ex_dev;
        int i;

        for (i = 0; i < ex->num_phys; i++) {
                struct ex_phy *phy = &ex->ex_phy[i];

                if (phy->phy_state == PHY_VACANT ||
                    phy->phy_state == PHY_NOT_PRESENT)
                        continue;

                if (dev_is_expander(phy->attached_dev_type) &&
                    phy->routing_attr == SUBTRACTIVE_ROUTING) {

                        memcpy(sub_addr, phy->attached_sas_addr, SAS_ADDR_SIZE);

                        return 1;
                }
        }
        return 0;
}

static int sas_check_level_subtractive_boundary(struct domain_device *dev)
{
        struct expander_device *ex = &dev->ex_dev;
        struct domain_device *child;
        u8 sub_addr[SAS_ADDR_SIZE] = {0, };

        list_for_each_entry(child, &ex->children, siblings) {
                if (!dev_is_expander(child->dev_type))
                        continue;
                if (sub_addr[0] == 0) {
                        sas_find_sub_addr(child, sub_addr);
                        continue;
                } else {
                        u8 s2[SAS_ADDR_SIZE];

                        if (sas_find_sub_addr(child, s2) &&
                            (SAS_ADDR(sub_addr) != SAS_ADDR(s2))) {

                                pr_notice("ex %016llx->%016llx-?->%016llx diverges from subtractive boundary %016llx\n",
                                          SAS_ADDR(dev->sas_addr),
                                          SAS_ADDR(child->sas_addr),
                                          SAS_ADDR(s2),
                                          SAS_ADDR(sub_addr));

                                sas_ex_disable_port(child, s2);
                        }
                }
        }
        return 0;
}
/**
 * sas_ex_discover_devices - discover devices attached to this expander
 * @dev: pointer to the expander domain device
 * @single: if you want to do a single phy, else set to -1;
 *
 * Configure this expander for use with its devices and register the
 * devices of this expander.
 */
static int sas_ex_discover_devices(struct domain_device *dev, int single)
{
        struct expander_device *ex = &dev->ex_dev;
        int i = 0, end = ex->num_phys;
        int res = 0;

        if (0 <= single && single < end) {
                i = single;
                end = i+1;
        }

        for ( ; i < end; i++) {
                struct ex_phy *ex_phy = &ex->ex_phy[i];

                if (ex_phy->phy_state == PHY_VACANT ||
                    ex_phy->phy_state == PHY_NOT_PRESENT ||
                    ex_phy->phy_state == PHY_DEVICE_DISCOVERED)
                        continue;

                switch (ex_phy->linkrate) {
                case SAS_PHY_DISABLED:
                case SAS_PHY_RESET_PROBLEM:
                case SAS_SATA_PORT_SELECTOR:
                        continue;
                default:
                        res = sas_ex_discover_dev(dev, i);
                        if (res)
                                break;
                        continue;
                }
        }

        if (!res)
                sas_check_level_subtractive_boundary(dev);

        return res;
}

static int sas_check_ex_subtractive_boundary(struct domain_device *dev)
{
        struct expander_device *ex = &dev->ex_dev;
        int i;
        u8  *sub_sas_addr = NULL;

        if (dev->dev_type != SAS_EDGE_EXPANDER_DEVICE)
                return 0;

        for (i = 0; i < ex->num_phys; i++) {
                struct ex_phy *phy = &ex->ex_phy[i];

                if (phy->phy_state == PHY_VACANT ||
                    phy->phy_state == PHY_NOT_PRESENT)
                        continue;

                if (dev_is_expander(phy->attached_dev_type) &&
                    phy->routing_attr == SUBTRACTIVE_ROUTING) {

                        if (!sub_sas_addr)
                                sub_sas_addr = &phy->attached_sas_addr[0];
                        else if (SAS_ADDR(sub_sas_addr) !=
                                 SAS_ADDR(phy->attached_sas_addr)) {

                                pr_notice("ex %016llx phy%02d diverges(%016llx) on subtractive boundary(%016llx). Disabled\n",
                                          SAS_ADDR(dev->sas_addr), i,
                                          SAS_ADDR(phy->attached_sas_addr),
                                          SAS_ADDR(sub_sas_addr));
                                sas_ex_disable_phy(dev, i);
                        }
                }
        }
        return 0;
}

static void sas_print_parent_topology_bug(struct domain_device *child,
                                                 struct ex_phy *parent_phy,
                                                 struct ex_phy *child_phy)
{
        static const char *ex_type[] = {
                [SAS_EDGE_EXPANDER_DEVICE] = "edge",
                [SAS_FANOUT_EXPANDER_DEVICE] = "fanout",
        };
        struct domain_device *parent = child->parent;

        pr_notice("%s ex %016llx phy%02d <--> %s ex %016llx phy%02d has %c:%c routing link!\n",
                  ex_type[parent->dev_type],
                  SAS_ADDR(parent->sas_addr),
                  parent_phy->phy_id,

                  ex_type[child->dev_type],
                  SAS_ADDR(child->sas_addr),
                  child_phy->phy_id,

                  sas_route_char(parent, parent_phy),
                  sas_route_char(child, child_phy));
}

static int sas_check_eeds(struct domain_device *child,
                                 struct ex_phy *parent_phy,
                                 struct ex_phy *child_phy)
{
        int res = 0;
        struct domain_device *parent = child->parent;

        if (SAS_ADDR(parent->port->disc.fanout_sas_addr) != 0) {
                res = -ENODEV;
                pr_warn("edge ex %016llx phy S:%02d <--> edge ex %016llx phy S:%02d, while there is a fanout ex %016llx\n",
                        SAS_ADDR(parent->sas_addr),
                        parent_phy->phy_id,
                        SAS_ADDR(child->sas_addr),
                        child_phy->phy_id,
                        SAS_ADDR(parent->port->disc.fanout_sas_addr));
        } else if (SAS_ADDR(parent->port->disc.eeds_a) == 0) {
                memcpy(parent->port->disc.eeds_a, parent->sas_addr,
                       SAS_ADDR_SIZE);
                memcpy(parent->port->disc.eeds_b, child->sas_addr,
                       SAS_ADDR_SIZE);
        } else if (((SAS_ADDR(parent->port->disc.eeds_a) ==
                    SAS_ADDR(parent->sas_addr)) ||
                   (SAS_ADDR(parent->port->disc.eeds_a) ==
                    SAS_ADDR(child->sas_addr)))
                   &&
                   ((SAS_ADDR(parent->port->disc.eeds_b) ==
                     SAS_ADDR(parent->sas_addr)) ||
                    (SAS_ADDR(parent->port->disc.eeds_b) ==
                     SAS_ADDR(child->sas_addr))))
                ;
        else {
                res = -ENODEV;
                pr_warn("edge ex %016llx phy%02d <--> edge ex %016llx phy%02d link forms a third EEDS!\n",
                        SAS_ADDR(parent->sas_addr),
                        parent_phy->phy_id,
                        SAS_ADDR(child->sas_addr),
                        child_phy->phy_id);
        }

        return res;
}

/* Here we spill over 80 columns.  It is intentional.
 */
static int sas_check_parent_topology(struct domain_device *child)
{
        struct expander_device *child_ex = &child->ex_dev;
        struct expander_device *parent_ex;
        int i;
        int res = 0;

        if (!child->parent)
                return 0;

        if (!dev_is_expander(child->parent->dev_type))
                return 0;

        parent_ex = &child->parent->ex_dev;

        for (i = 0; i < parent_ex->num_phys; i++) {
                struct ex_phy *parent_phy = &parent_ex->ex_phy[i];
                struct ex_phy *child_phy;

                if (parent_phy->phy_state == PHY_VACANT ||
                    parent_phy->phy_state == PHY_NOT_PRESENT)
                        continue;

                if (SAS_ADDR(parent_phy->attached_sas_addr) != SAS_ADDR(child->sas_addr))
                        continue;

                child_phy = &child_ex->ex_phy[parent_phy->attached_phy_id];

                switch (child->parent->dev_type) {
                case SAS_EDGE_EXPANDER_DEVICE:
                        if (child->dev_type == SAS_FANOUT_EXPANDER_DEVICE) {
                                if (parent_phy->routing_attr != SUBTRACTIVE_ROUTING ||
                                    child_phy->routing_attr != TABLE_ROUTING) {
                                        sas_print_parent_topology_bug(child, parent_phy, child_phy);
                                        res = -ENODEV;
                                }
                        } else if (parent_phy->routing_attr == SUBTRACTIVE_ROUTING) {
                                if (child_phy->routing_attr == SUBTRACTIVE_ROUTING) {
                                        res = sas_check_eeds(child, parent_phy, child_phy);
                                } else if (child_phy->routing_attr != TABLE_ROUTING) {
                                        sas_print_parent_topology_bug(child, parent_phy, child_phy);
                                        res = -ENODEV;
                                }
                        } else if (parent_phy->routing_attr == TABLE_ROUTING) {
                                if (child_phy->routing_attr == SUBTRACTIVE_ROUTING ||
                                    (child_phy->routing_attr == TABLE_ROUTING &&
                                     child_ex->t2t_supp && parent_ex->t2t_supp)) {
                                        /* All good */;
                                } else {
                                        sas_print_parent_topology_bug(child, parent_phy, child_phy);
                                        res = -ENODEV;
                                }
                        }
                        break;
                case SAS_FANOUT_EXPANDER_DEVICE:
                        if (parent_phy->routing_attr != TABLE_ROUTING ||
                            child_phy->routing_attr != SUBTRACTIVE_ROUTING) {
                                sas_print_parent_topology_bug(child, parent_phy, child_phy);
                                res = -ENODEV;
                        }
                        break;
                default:
                        break;
                }
        }

        return res;
}

#define RRI_REQ_SIZE  16
#define RRI_RESP_SIZE 44

static int sas_configure_present(struct domain_device *dev, int phy_id,
                                 u8 *sas_addr, int *index, int *present)
{
        int i, res = 0;
        struct expander_device *ex = &dev->ex_dev;
        struct ex_phy *phy = &ex->ex_phy[phy_id];
        u8 *rri_req;
        u8 *rri_resp;

        *present = 0;
        *index = 0;

        rri_req = alloc_smp_req(RRI_REQ_SIZE);
        if (!rri_req)
                return -ENOMEM;

        rri_resp = alloc_smp_resp(RRI_RESP_SIZE);
        if (!rri_resp) {
                kfree(rri_req);
                return -ENOMEM;
        }

        rri_req[1] = SMP_REPORT_ROUTE_INFO;
        rri_req[9] = phy_id;

        for (i = 0; i < ex->max_route_indexes ; i++) {
                *(__be16 *)(rri_req+6) = cpu_to_be16(i);
                res = smp_execute_task(dev, rri_req, RRI_REQ_SIZE, rri_resp,
                                       RRI_RESP_SIZE);
                if (res)
                        goto out;
                res = rri_resp[2];
                if (res == SMP_RESP_NO_INDEX) {
                        pr_warn("overflow of indexes: dev %016llx phy%02d index 0x%x\n",
                                SAS_ADDR(dev->sas_addr), phy_id, i);
                        goto out;
                } else if (res != SMP_RESP_FUNC_ACC) {
                        pr_notice("%s: dev %016llx phy%02d index 0x%x result 0x%x\n",
                                  __func__, SAS_ADDR(dev->sas_addr), phy_id,
                                  i, res);
                        goto out;
                }
                if (SAS_ADDR(sas_addr) != 0) {
                        if (SAS_ADDR(rri_resp+16) == SAS_ADDR(sas_addr)) {
                                *index = i;
                                if ((rri_resp[12] & 0x80) == 0x80)
                                        *present = 0;
                                else
                                        *present = 1;
                                goto out;
                        } else if (SAS_ADDR(rri_resp+16) == 0) {
                                *index = i;
                                *present = 0;
                                goto out;
                        }
                } else if (SAS_ADDR(rri_resp+16) == 0 &&
                           phy->last_da_index < i) {
                        phy->last_da_index = i;
                        *index = i;
                        *present = 0;
                        goto out;
                }
        }
        res = -1;
out:
        kfree(rri_req);
        kfree(rri_resp);
        return res;
}

#define CRI_REQ_SIZE  44
#define CRI_RESP_SIZE  8

static int sas_configure_set(struct domain_device *dev, int phy_id,
                             u8 *sas_addr, int index, int include)
{
        int res;
        u8 *cri_req;
        u8 *cri_resp;

        cri_req = alloc_smp_req(CRI_REQ_SIZE);
        if (!cri_req)
                return -ENOMEM;

        cri_resp = alloc_smp_resp(CRI_RESP_SIZE);
        if (!cri_resp) {
                kfree(cri_req);
                return -ENOMEM;
        }

        cri_req[1] = SMP_CONF_ROUTE_INFO;
        *(__be16 *)(cri_req+6) = cpu_to_be16(index);
        cri_req[9] = phy_id;
        if (SAS_ADDR(sas_addr) == 0 || !include)
                cri_req[12] |= 0x80;
        memcpy(cri_req+16, sas_addr, SAS_ADDR_SIZE);

        res = smp_execute_task(dev, cri_req, CRI_REQ_SIZE, cri_resp,
                               CRI_RESP_SIZE);
        if (res)
                goto out;
        res = cri_resp[2];
        if (res == SMP_RESP_NO_INDEX) {
                pr_warn("overflow of indexes: dev %016llx phy%02d index 0x%x\n",
                        SAS_ADDR(dev->sas_addr), phy_id, index);
        }
out:
        kfree(cri_req);
        kfree(cri_resp);
        return res;
}

static int sas_configure_phy(struct domain_device *dev, int phy_id,
                                    u8 *sas_addr, int include)
{
        int index;
        int present;
        int res;

        res = sas_configure_present(dev, phy_id, sas_addr, &index, &present);
        if (res)
                return res;
        if (include ^ present)
                return sas_configure_set(dev, phy_id, sas_addr, index,
                                         include);

        return res;
}

/**
 * sas_configure_parent - configure routing table of parent
 * @parent: parent expander
 * @child: child expander
 * @sas_addr: SAS port identifier of device directly attached to child
 * @include: whether or not to include @child in the expander routing table
 */
static int sas_configure_parent(struct domain_device *parent,
                                struct domain_device *child,
                                u8 *sas_addr, int include)
{
        struct expander_device *ex_parent = &parent->ex_dev;
        int res = 0;
        int i;

        if (parent->parent) {
                res = sas_configure_parent(parent->parent, parent, sas_addr,
                                           include);
                if (res)
                        return res;
        }

        if (ex_parent->conf_route_table == 0) {
                pr_debug("ex %016llx has self-configuring routing table\n",
                         SAS_ADDR(parent->sas_addr));
                return 0;
        }

        for (i = 0; i < ex_parent->num_phys; i++) {
                struct ex_phy *phy = &ex_parent->ex_phy[i];

                if ((phy->routing_attr == TABLE_ROUTING) &&
                    (SAS_ADDR(phy->attached_sas_addr) ==
                     SAS_ADDR(child->sas_addr))) {
                        res = sas_configure_phy(parent, i, sas_addr, include);
                        if (res)
                                return res;
                }
        }

        return res;
}

/**
 * sas_configure_routing - configure routing
 * @dev: expander device
 * @sas_addr: port identifier of device directly attached to the expander device
 */
static int sas_configure_routing(struct domain_device *dev, u8 *sas_addr)
{
        if (dev->parent)
                return sas_configure_parent(dev->parent, dev, sas_addr, 1);
        return 0;
}

static int sas_disable_routing(struct domain_device *dev,  u8 *sas_addr)
{
        if (dev->parent)
                return sas_configure_parent(dev->parent, dev, sas_addr, 0);
        return 0;
}

/**
 * sas_discover_expander - expander discovery
 * @dev: pointer to expander domain device
 *
 * See comment in sas_discover_sata().
 */
static int sas_discover_expander(struct domain_device *dev)
{
        int res;

        res = sas_notify_lldd_dev_found(dev);
        if (res)
                return res;

        res = sas_ex_general(dev);
        if (res)
                goto out_err;
        res = sas_ex_manuf_info(dev);
        if (res)
                goto out_err;

        res = sas_expander_discover(dev);
        if (res) {
                pr_warn("expander %016llx discovery failed(0x%x)\n",
                        SAS_ADDR(dev->sas_addr), res);
                goto out_err;
        }

        sas_check_ex_subtractive_boundary(dev);
        res = sas_check_parent_topology(dev);
        if (res)
                goto out_err;
        return 0;
out_err:
        sas_notify_lldd_dev_gone(dev);
        return res;
}

static int sas_ex_level_discovery(struct asd_sas_port *port, const int level)
{
        int res = 0;
        struct domain_device *dev;

        list_for_each_entry(dev, &port->dev_list, dev_list_node) {
                if (dev_is_expander(dev->dev_type)) {
                        struct sas_expander_device *ex =
                                rphy_to_expander_device(dev->rphy);

                        if (level == ex->level)
                                res = sas_ex_discover_devices(dev, -1);
                        else if (level > 0)
                                res = sas_ex_discover_devices(port->port_dev, -1);

                }
        }

        return res;
}

static int sas_ex_bfs_disc(struct asd_sas_port *port)
{
        int res;
        int level;

        do {
                level = port->disc.max_level;
                res = sas_ex_level_discovery(port, level);
                mb();
        } while (level < port->disc.max_level);

        return res;
}

int sas_discover_root_expander(struct domain_device *dev)
{
        int res;
        struct sas_expander_device *ex = rphy_to_expander_device(dev->rphy);

        res = sas_rphy_add(dev->rphy);
        if (res)
                goto out_err;

        ex->level = dev->port->disc.max_level; /* 0 */
        res = sas_discover_expander(dev);
        if (res)
                goto out_err2;

        sas_ex_bfs_disc(dev->port);

        return res;

out_err2:
        sas_rphy_remove(dev->rphy);
out_err:
        return res;
}

/* ---------- Domain revalidation ---------- */

static int sas_get_phy_discover(struct domain_device *dev,
                                int phy_id, struct smp_resp *disc_resp)
{
        int res;
        u8 *disc_req;

        disc_req = alloc_smp_req(DISCOVER_REQ_SIZE);
        if (!disc_req)
                return -ENOMEM;

        disc_req[1] = SMP_DISCOVER;
        disc_req[9] = phy_id;

        res = smp_execute_task(dev, disc_req, DISCOVER_REQ_SIZE,
                               disc_resp, DISCOVER_RESP_SIZE);
        if (res)
                goto out;
        else if (disc_resp->result != SMP_RESP_FUNC_ACC) {
                res = disc_resp->result;
                goto out;
        }
out:
        kfree(disc_req);
        return res;
}

static int sas_get_phy_change_count(struct domain_device *dev,
                                    int phy_id, int *pcc)
{
        int res;
        struct smp_resp *disc_resp;

        disc_resp = alloc_smp_resp(DISCOVER_RESP_SIZE);
        if (!disc_resp)
                return -ENOMEM;

        res = sas_get_phy_discover(dev, phy_id, disc_resp);
        if (!res)
                *pcc = disc_resp->disc.change_count;

        kfree(disc_resp);
        return res;
}

static int sas_get_phy_attached_dev(struct domain_device *dev, int phy_id,
                                    u8 *sas_addr, enum sas_device_type *type)
{
        int res;
        struct smp_resp *disc_resp;
        struct discover_resp *dr;

        disc_resp = alloc_smp_resp(DISCOVER_RESP_SIZE);
        if (!disc_resp)
                return -ENOMEM;
        dr = &disc_resp->disc;

        res = sas_get_phy_discover(dev, phy_id, disc_resp);
        if (res == 0) {
                memcpy(sas_addr, disc_resp->disc.attached_sas_addr,
                       SAS_ADDR_SIZE);
                *type = to_dev_type(dr);
                if (*type == 0)
                        memset(sas_addr, 0, SAS_ADDR_SIZE);
        }
        kfree(disc_resp);
        return res;
}

static int sas_find_bcast_phy(struct domain_device *dev, int *phy_id,
                              int from_phy, bool update)
{
        struct expander_device *ex = &dev->ex_dev;
        int res = 0;
        int i;

        for (i = from_phy; i < ex->num_phys; i++) {
                int phy_change_count = 0;

                res = sas_get_phy_change_count(dev, i, &phy_change_count);
                switch (res) {
                case SMP_RESP_PHY_VACANT:
                case SMP_RESP_NO_PHY:
                        continue;
                case SMP_RESP_FUNC_ACC:
                        break;
                default:
                        return res;
                }

                if (phy_change_count != ex->ex_phy[i].phy_change_count) {
                        if (update)
                                ex->ex_phy[i].phy_change_count =
                                        phy_change_count;
                        *phy_id = i;
                        return 0;
                }
        }
        return 0;
}

static int sas_get_ex_change_count(struct domain_device *dev, int *ecc)
{
        int res;
        u8  *rg_req;
        struct smp_resp  *rg_resp;

        rg_req = alloc_smp_req(RG_REQ_SIZE);
        if (!rg_req)
                return -ENOMEM;

        rg_resp = alloc_smp_resp(RG_RESP_SIZE);
        if (!rg_resp) {
                kfree(rg_req);
                return -ENOMEM;
        }

        rg_req[1] = SMP_REPORT_GENERAL;

        res = smp_execute_task(dev, rg_req, RG_REQ_SIZE, rg_resp,
                               RG_RESP_SIZE);
        if (res)
                goto out;
        if (rg_resp->result != SMP_RESP_FUNC_ACC) {
                res = rg_resp->result;
                goto out;
        }

        *ecc = be16_to_cpu(rg_resp->rg.change_count);
out:
        kfree(rg_resp);
        kfree(rg_req);
        return res;
}
/**
 * sas_find_bcast_dev -  find the device issue BROADCAST(CHANGE).
 * @dev:domain device to be detect.
 * @src_dev: the device which originated BROADCAST(CHANGE).
 *
 * Add self-configuration expander support. Suppose two expander cascading,
 * when the first level expander is self-configuring, hotplug the disks in
 * second level expander, BROADCAST(CHANGE) will not only be originated
 * in the second level expander, but also be originated in the first level
 * expander (see SAS protocol SAS 2r-14, 7.11 for detail), it is to say,
 * expander changed count in two level expanders will all increment at least
 * once, but the phy which chang count has changed is the source device which
 * we concerned.
 */

static int sas_find_bcast_dev(struct domain_device *dev,
                              struct domain_device **src_dev)
{
        struct expander_device *ex = &dev->ex_dev;
        int ex_change_count = -1;
        int phy_id = -1;
        int res;
        struct domain_device *ch;

        res = sas_get_ex_change_count(dev, &ex_change_count);
        if (res)
                goto out;
        if (ex_change_count != -1 && ex_change_count != ex->ex_change_count) {
                /* Just detect if this expander phys phy change count changed,
                * in order to determine if this expander originate BROADCAST,
                * and do not update phy change count field in our structure.
                */
                res = sas_find_bcast_phy(dev, &phy_id, 0, false);
                if (phy_id != -1) {
                        *src_dev = dev;
                        ex->ex_change_count = ex_change_count;
                        pr_info("ex %016llx phy%02d change count has changed\n",
                                SAS_ADDR(dev->sas_addr), phy_id);
                        return res;
                } else
                        pr_info("ex %016llx phys DID NOT change\n",
                                SAS_ADDR(dev->sas_addr));
        }
        list_for_each_entry(ch, &ex->children, siblings) {
                if (dev_is_expander(ch->dev_type)) {
                        res = sas_find_bcast_dev(ch, src_dev);
                        if (*src_dev)
                                return res;
                }
        }
out:
        return res;
}

static void sas_unregister_ex_tree(struct asd_sas_port *port, struct domain_device *dev)
{
        struct expander_device *ex = &dev->ex_dev;
        struct domain_device *child, *n;

        list_for_each_entry_safe(child, n, &ex->children, siblings) {
                set_bit(SAS_DEV_GONE, &child->state);
                if (dev_is_expander(child->dev_type))
                        sas_unregister_ex_tree(port, child);
                else
                        sas_unregister_dev(port, child);
        }
        sas_unregister_dev(port, dev);
}

static void sas_unregister_devs_sas_addr(struct domain_device *parent,
                                         int phy_id, bool last)
{
        struct expander_device *ex_dev = &parent->ex_dev;
        struct ex_phy *phy = &ex_dev->ex_phy[phy_id];
        struct domain_device *child, *n, *found = NULL;
        if (last) {
                list_for_each_entry_safe(child, n,
                        &ex_dev->children, siblings) {
                        if (SAS_ADDR(child->sas_addr) ==
                            SAS_ADDR(phy->attached_sas_addr)) {
                                set_bit(SAS_DEV_GONE, &child->state);
                                if (dev_is_expander(child->dev_type))
                                        sas_unregister_ex_tree(parent->port, child);
                                else
                                        sas_unregister_dev(parent->port, child);
                                found = child;
                                break;
                        }
                }
                sas_disable_routing(parent, phy->attached_sas_addr);
        }
        memset(phy->attached_sas_addr, 0, SAS_ADDR_SIZE);
        if (phy->port) {
                sas_port_delete_phy(phy->port, phy->phy);
                sas_device_set_phy(found, phy->port);
                if (phy->port->num_phys == 0)
                        list_add_tail(&phy->port->del_list,
                                &parent->port->sas_port_del_list);
                phy->port = NULL;
        }
}

static int sas_discover_bfs_by_root_level(struct domain_device *root,
                                          const int level)
{
        struct expander_device *ex_root = &root->ex_dev;
        struct domain_device *child;
        int res = 0;

        list_for_each_entry(child, &ex_root->children, siblings) {
                if (dev_is_expander(child->dev_type)) {
                        struct sas_expander_device *ex =
                                rphy_to_expander_device(child->rphy);

                        if (level > ex->level)
                                res = sas_discover_bfs_by_root_level(child,
                                                                     level);
                        else if (level == ex->level)
                                res = sas_ex_discover_devices(child, -1);
                }
        }
        return res;
}

static int sas_discover_bfs_by_root(struct domain_device *dev)
{
        int res;
        struct sas_expander_device *ex = rphy_to_expander_device(dev->rphy);
        int level = ex->level+1;

        res = sas_ex_discover_devices(dev, -1);
        if (res)
                goto out;
        do {
                res = sas_discover_bfs_by_root_level(dev, level);
                mb();
                level += 1;
        } while (level <= dev->port->disc.max_level);
out:
        return res;
}

static int sas_discover_new(struct domain_device *dev, int phy_id)
{
        struct ex_phy *ex_phy = &dev->ex_dev.ex_phy[phy_id];
        struct domain_device *child;
        int res;

        pr_debug("ex %016llx phy%02d new device attached\n",
                 SAS_ADDR(dev->sas_addr), phy_id);
        res = sas_ex_phy_discover(dev, phy_id);
        if (res)
                return res;

        if (sas_ex_join_wide_port(dev, phy_id))
                return 0;

        res = sas_ex_discover_devices(dev, phy_id);
        if (res)
                return res;
        list_for_each_entry(child, &dev->ex_dev.children, siblings) {
                if (SAS_ADDR(child->sas_addr) ==
                    SAS_ADDR(ex_phy->attached_sas_addr)) {
                        if (dev_is_expander(child->dev_type))
                                res = sas_discover_bfs_by_root(child);
                        break;
                }
        }
        return res;
}

static bool dev_type_flutter(enum sas_device_type new, enum sas_device_type old)
{
        if (old == new)
                return true;

        /* treat device directed resets as flutter, if we went
         * SAS_END_DEVICE to SAS_SATA_PENDING the link needs recovery
         */
        if ((old == SAS_SATA_PENDING && new == SAS_END_DEVICE) ||
            (old == SAS_END_DEVICE && new == SAS_SATA_PENDING))
                return true;

        return false;
}

static int sas_rediscover_dev(struct domain_device *dev, int phy_id,
                              bool last, int sibling)
{
        struct expander_device *ex = &dev->ex_dev;
        struct ex_phy *phy = &ex->ex_phy[phy_id];
        enum sas_device_type type = SAS_PHY_UNUSED;

        u8 sas_addr[SAS_ADDR_SIZE];
        char msg[80] = "";
        int res;

        if (!last)
                sprintf(msg, ", part of a wide port with phy%02d", sibling);

        pr_debug("ex %016llx rediscovering phy%02d%s\n",
                 SAS_ADDR(dev->sas_addr), phy_id, msg);

        memset(sas_addr, 0, SAS_ADDR_SIZE);
        res = sas_get_phy_attached_dev(dev, phy_id, sas_addr, &type);
        switch (res) {
        case SMP_RESP_NO_PHY:
                phy->phy_state = PHY_NOT_PRESENT;
                sas_unregister_devs_sas_addr(dev, phy_id, last);
                return res;
        case SMP_RESP_PHY_VACANT:
                phy->phy_state = PHY_VACANT;
                sas_unregister_devs_sas_addr(dev, phy_id, last);
                return res;
        case SMP_RESP_FUNC_ACC:
                break;
        case -ECOMM:
                break;
        default:
                return res;
        }

        if ((SAS_ADDR(sas_addr) == 0) || (res == -ECOMM)) {
                phy->phy_state = PHY_EMPTY;
                sas_unregister_devs_sas_addr(dev, phy_id, last);
                /*
                 * Even though the PHY is empty, for convenience we discover
                 * the PHY to update the PHY info, like negotiated linkrate.
                 */
                sas_ex_phy_discover(dev, phy_id);
                return res;
        } else if (SAS_ADDR(sas_addr) == SAS_ADDR(phy->attached_sas_addr) &&
                   dev_type_flutter(type, phy->attached_dev_type)) {
                struct domain_device *ata_dev = sas_ex_to_ata(dev, phy_id);
                char *action = "";

                sas_ex_phy_discover(dev, phy_id);

                if (ata_dev && phy->attached_dev_type == SAS_SATA_PENDING)
                        action = ", needs recovery";
                pr_debug("ex %016llx phy%02d broadcast flutter%s\n",
                         SAS_ADDR(dev->sas_addr), phy_id, action);
                return res;
        }

        /* we always have to delete the old device when we went here */
        pr_info("ex %016llx phy%02d replace %016llx\n",
                SAS_ADDR(dev->sas_addr), phy_id,
                SAS_ADDR(phy->attached_sas_addr));
        sas_unregister_devs_sas_addr(dev, phy_id, last);

        return sas_discover_new(dev, phy_id);
}

/**
 * sas_rediscover - revalidate the domain.
 * @dev:domain device to be detect.
 * @phy_id: the phy id will be detected.
 *
 * NOTE: this process _must_ quit (return) as soon as any connection
 * errors are encountered.  Connection recovery is done elsewhere.
 * Discover process only interrogates devices in order to discover the
 * domain.For plugging out, we un-register the device only when it is
 * the last phy in the port, for other phys in this port, we just delete it
 * from the port.For inserting, we do discovery when it is the
 * first phy,for other phys in this port, we add it to the port to
 * forming the wide-port.
 */
static int sas_rediscover(struct domain_device *dev, const int phy_id)
{
        struct expander_device *ex = &dev->ex_dev;
        struct ex_phy *changed_phy = &ex->ex_phy[phy_id];
        int res = 0;
        int i;
        bool last = true;       /* is this the last phy of the port */

        pr_debug("ex %016llx phy%02d originated BROADCAST(CHANGE)\n",
                 SAS_ADDR(dev->sas_addr), phy_id);

        if (SAS_ADDR(changed_phy->attached_sas_addr) != 0) {
                for (i = 0; i < ex->num_phys; i++) {
                        struct ex_phy *phy = &ex->ex_phy[i];

                        if (i == phy_id)
                                continue;
                        if (SAS_ADDR(phy->attached_sas_addr) ==
                            SAS_ADDR(changed_phy->attached_sas_addr)) {
                                last = false;
                                break;
                        }
                }
                res = sas_rediscover_dev(dev, phy_id, last, i);
        } else
                res = sas_discover_new(dev, phy_id);
        return res;
}

/**
 * sas_ex_revalidate_domain - revalidate the domain
 * @port_dev: port domain device.
 *
 * NOTE: this process _must_ quit (return) as soon as any connection
 * errors are encountered.  Connection recovery is done elsewhere.
 * Discover process only interrogates devices in order to discover the
 * domain.
 */
int sas_ex_revalidate_domain(struct domain_device *port_dev)
{
        int res;
        struct domain_device *dev = NULL;

        res = sas_find_bcast_dev(port_dev, &dev);
        if (res == 0 && dev) {
                struct expander_device *ex = &dev->ex_dev;
                int i = 0, phy_id;

                do {
                        phy_id = -1;
                        res = sas_find_bcast_phy(dev, &phy_id, i, true);
                        if (phy_id == -1)
                                break;
                        res = sas_rediscover(dev, phy_id);
                        i = phy_id + 1;
                } while (i < ex->num_phys);
        }
        return res;
}

void sas_smp_handler(struct bsg_job *job, struct Scsi_Host *shost,
                struct sas_rphy *rphy)
{
        struct domain_device *dev;
        unsigned int rcvlen = 0;
        int ret = -EINVAL;

        /* no rphy means no smp target support (ie aic94xx host) */
        if (!rphy)
                return sas_smp_host_handler(job, shost);

        switch (rphy->identify.device_type) {
        case SAS_EDGE_EXPANDER_DEVICE:
        case SAS_FANOUT_EXPANDER_DEVICE:
                break;
        default:
                pr_err("%s: can we send a smp request to a device?\n",
                       __func__);
                goto out;
        }

        dev = sas_find_dev_by_rphy(rphy);
        if (!dev) {
                pr_err("%s: fail to find a domain_device?\n", __func__);
                goto out;
        }

        /* do we need to support multiple segments? */
        if (job->request_payload.sg_cnt > 1 ||
            job->reply_payload.sg_cnt > 1) {
                pr_info("%s: multiple segments req %u, rsp %u\n",
                        __func__, job->request_payload.payload_len,
                        job->reply_payload.payload_len);
                goto out;
        }

        ret = smp_execute_task_sg(dev, job->request_payload.sg_list,
                        job->reply_payload.sg_list);
        if (ret >= 0) {
                /* bsg_job_done() requires the length received  */
                rcvlen = job->reply_payload.payload_len - ret;
                ret = 0;
        }

out:
        bsg_job_done(job, ret, rcvlen);
}