/*
 * zfcp device driver
 *
 * Module interface and handling of zfcp data structures.
 *
 * Copyright IBM Corp. 2002, 2013
 */

/*
 * Driver authors:
 *            Martin Peschke (originator of the driver)
 *            Raimund Schroeder
 *            Aron Zeh
 *            Wolfgang Taphorn
 *            Stefan Bader
 *            Heiko Carstens (kernel 2.6 port of the driver)
 *            Andreas Herrmann
 *            Maxim Shchetynin
 *            Volker Sameske
 *            Ralph Wuerthner
 *            Michael Loehr
 *            Swen Schillig
 *            Christof Schmitt
 *            Martin Petermann
 *            Sven Schuetz
 *            Steffen Maier
 */

#define KMSG_COMPONENT "zfcp"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/miscdevice.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/module.h>
#include "zfcp_ext.h"
#include "zfcp_fc.h"
#include "zfcp_reqlist.h"

#define ZFCP_BUS_ID_SIZE        20

MODULE_AUTHOR("IBM Deutschland Entwicklung GmbH - linux390@de.ibm.com");
MODULE_DESCRIPTION("FCP HBA driver");
MODULE_LICENSE("GPL");

static char *init_device;
module_param_named(device, init_device, charp, 0400);
MODULE_PARM_DESC(device, "specify initial device");

static struct kmem_cache * __init zfcp_cache_hw_align(const char *name,
                                                      unsigned long size)
{
        return kmem_cache_create(name, size, roundup_pow_of_two(size), 0, NULL);
}

static void __init zfcp_init_device_configure(char *busid, u64 wwpn, u64 lun)
{
        struct ccw_device *cdev;
        struct zfcp_adapter *adapter;
        struct zfcp_port *port;

        cdev = get_ccwdev_by_busid(&zfcp_ccw_driver, busid);
        if (!cdev)
                return;

        if (ccw_device_set_online(cdev))
                goto out_ccw_device;

        adapter = zfcp_ccw_adapter_by_cdev(cdev);
        if (!adapter)
                goto out_ccw_device;

        port = zfcp_get_port_by_wwpn(adapter, wwpn);
        if (!port)
                goto out_port;
        flush_work(&port->rport_work);

        zfcp_unit_add(port, lun);
        put_device(&port->dev);

out_port:
        zfcp_ccw_adapter_put(adapter);
out_ccw_device:
        put_device(&cdev->dev);
        return;
}

static void __init zfcp_init_device_setup(char *devstr)
{
        char *token;
        char *str, *str_saved;
        char busid[ZFCP_BUS_ID_SIZE];
        u64 wwpn, lun;

        /* duplicate devstr and keep the original for sysfs presentation*/
        str_saved = kstrdup(devstr, GFP_KERNEL);
        str = str_saved;
        if (!str)
                return;

        token = strsep(&str, ",");
        if (!token || strlen(token) >= ZFCP_BUS_ID_SIZE)
                goto err_out;
        strncpy(busid, token, ZFCP_BUS_ID_SIZE);

        token = strsep(&str, ",");
        if (!token || strict_strtoull(token, 0, (unsigned long long *) &wwpn))
                goto err_out;

        token = strsep(&str, ",");
        if (!token || strict_strtoull(token, 0, (unsigned long long *) &lun))
                goto err_out;

        kfree(str_saved);
        zfcp_init_device_configure(busid, wwpn, lun);
        return;

err_out:
        kfree(str_saved);
        pr_err("%s is not a valid SCSI device\n", devstr);
}

static int __init zfcp_module_init(void)
{
        int retval = -ENOMEM;

        zfcp_fsf_qtcb_cache = zfcp_cache_hw_align("zfcp_fsf_qtcb",
                                                  sizeof(struct fsf_qtcb));
        if (!zfcp_fsf_qtcb_cache)
                goto out_qtcb_cache;

        zfcp_fc_req_cache = zfcp_cache_hw_align("zfcp_fc_req",
                                                sizeof(struct zfcp_fc_req));
        if (!zfcp_fc_req_cache)
                goto out_fc_cache;

        zfcp_scsi_transport_template =
                fc_attach_transport(&zfcp_transport_functions);
        if (!zfcp_scsi_transport_template)
                goto out_transport;
        scsi_transport_reserve_device(zfcp_scsi_transport_template,
                                      sizeof(struct zfcp_scsi_dev));

        retval = ccw_driver_register(&zfcp_ccw_driver);
        if (retval) {
                pr_err("The zfcp device driver could not register with "
                       "the common I/O layer\n");
                goto out_ccw_register;
        }

        if (init_device)
                zfcp_init_device_setup(init_device);
        return 0;

out_ccw_register:
        fc_release_transport(zfcp_scsi_transport_template);
out_transport:
        kmem_cache_destroy(zfcp_fc_req_cache);
out_fc_cache:
        kmem_cache_destroy(zfcp_fsf_qtcb_cache);
out_qtcb_cache:
        return retval;
}

module_init(zfcp_module_init);

static void __exit zfcp_module_exit(void)
{
        ccw_driver_unregister(&zfcp_ccw_driver);
        fc_release_transport(zfcp_scsi_transport_template);
        kmem_cache_destroy(zfcp_fc_req_cache);
        kmem_cache_destroy(zfcp_fsf_qtcb_cache);
}

module_exit(zfcp_module_exit);

/**
 * zfcp_get_port_by_wwpn - find port in port list of adapter by wwpn
 * @adapter: pointer to adapter to search for port
 * @wwpn: wwpn to search for
 *
 * Returns: pointer to zfcp_port or NULL
 */
struct zfcp_port *zfcp_get_port_by_wwpn(struct zfcp_adapter *adapter,
                                        u64 wwpn)
{
        unsigned long flags;
        struct zfcp_port *port;

        read_lock_irqsave(&adapter->port_list_lock, flags);
        list_for_each_entry(port, &adapter->port_list, list)
                if (port->wwpn == wwpn) {
                        if (!get_device(&port->dev))
                                port = NULL;
                        read_unlock_irqrestore(&adapter->port_list_lock, flags);
                        return port;
                }
        read_unlock_irqrestore(&adapter->port_list_lock, flags);
        return NULL;
}

static int zfcp_allocate_low_mem_buffers(struct zfcp_adapter *adapter)
{
        adapter->pool.erp_req =
                mempool_create_kmalloc_pool(1, sizeof(struct zfcp_fsf_req));
        if (!adapter->pool.erp_req)
                return -ENOMEM;

        adapter->pool.gid_pn_req =
                mempool_create_kmalloc_pool(1, sizeof(struct zfcp_fsf_req));
        if (!adapter->pool.gid_pn_req)
                return -ENOMEM;

        adapter->pool.scsi_req =
                mempool_create_kmalloc_pool(1, sizeof(struct zfcp_fsf_req));
        if (!adapter->pool.scsi_req)
                return -ENOMEM;

        adapter->pool.scsi_abort =
                mempool_create_kmalloc_pool(1, sizeof(struct zfcp_fsf_req));
        if (!adapter->pool.scsi_abort)
                return -ENOMEM;

        adapter->pool.status_read_req =
                mempool_create_kmalloc_pool(FSF_STATUS_READS_RECOM,
                                            sizeof(struct zfcp_fsf_req));
        if (!adapter->pool.status_read_req)
                return -ENOMEM;

        adapter->pool.qtcb_pool =
                mempool_create_slab_pool(4, zfcp_fsf_qtcb_cache);
        if (!adapter->pool.qtcb_pool)
                return -ENOMEM;

        BUILD_BUG_ON(sizeof(struct fsf_status_read_buffer) > PAGE_SIZE);
        adapter->pool.sr_data =
                mempool_create_page_pool(FSF_STATUS_READS_RECOM, 0);
        if (!adapter->pool.sr_data)
                return -ENOMEM;

        adapter->pool.gid_pn =
                mempool_create_slab_pool(1, zfcp_fc_req_cache);
        if (!adapter->pool.gid_pn)
                return -ENOMEM;

        return 0;
}

static void zfcp_free_low_mem_buffers(struct zfcp_adapter *adapter)
{
        if (adapter->pool.erp_req)
                mempool_destroy(adapter->pool.erp_req);
        if (adapter->pool.scsi_req)
                mempool_destroy(adapter->pool.scsi_req);
        if (adapter->pool.scsi_abort)
                mempool_destroy(adapter->pool.scsi_abort);
        if (adapter->pool.qtcb_pool)
                mempool_destroy(adapter->pool.qtcb_pool);
        if (adapter->pool.status_read_req)
                mempool_destroy(adapter->pool.status_read_req);
        if (adapter->pool.sr_data)
                mempool_destroy(adapter->pool.sr_data);
        if (adapter->pool.gid_pn)
                mempool_destroy(adapter->pool.gid_pn);
}

/**
 * zfcp_status_read_refill - refill the long running status_read_requests
 * @adapter: ptr to struct zfcp_adapter for which the buffers should be refilled
 *
 * Returns: 0 on success, 1 otherwise
 *
 * if there are 16 or more status_read requests missing an adapter_reopen
 * is triggered
 */
int zfcp_status_read_refill(struct zfcp_adapter *adapter)
{
        while (atomic_read(&adapter->stat_miss) > 0)
                if (zfcp_fsf_status_read(adapter->qdio)) {
                        if (atomic_read(&adapter->stat_miss) >=
                            adapter->stat_read_buf_num) {
                                zfcp_erp_adapter_reopen(adapter, 0, "axsref1");
                                return 1;
                        }
                        break;
                } else
                        atomic_dec(&adapter->stat_miss);
        return 0;
}

static void _zfcp_status_read_scheduler(struct work_struct *work)
{
        zfcp_status_read_refill(container_of(work, struct zfcp_adapter,
                                             stat_work));
}

static void zfcp_print_sl(struct seq_file *m, struct service_level *sl)
{
        struct zfcp_adapter *adapter =
                container_of(sl, struct zfcp_adapter, service_level);

        seq_printf(m, "zfcp: %s microcode level %x\n",
                   dev_name(&adapter->ccw_device->dev),
                   adapter->fsf_lic_version);
}

static int zfcp_setup_adapter_work_queue(struct zfcp_adapter *adapter)
{
        char name[TASK_COMM_LEN];

        snprintf(name, sizeof(name), "zfcp_q_%s",
                 dev_name(&adapter->ccw_device->dev));
        adapter->work_queue = create_singlethread_workqueue(name);

        if (adapter->work_queue)
                return 0;
        return -ENOMEM;
}

static void zfcp_destroy_adapter_work_queue(struct zfcp_adapter *adapter)
{
        if (adapter->work_queue)
                destroy_workqueue(adapter->work_queue);
        adapter->work_queue = NULL;

}

/**
 * zfcp_adapter_enqueue - enqueue a new adapter to the list
 * @ccw_device: pointer to the struct cc_device
 *
 * Returns:     struct zfcp_adapter*
 * Enqueues an adapter at the end of the adapter list in the driver data.
 * All adapter internal structures are set up.
 * Proc-fs entries are also created.
 */
struct zfcp_adapter *zfcp_adapter_enqueue(struct ccw_device *ccw_device)
{
        struct zfcp_adapter *adapter;

        if (!get_device(&ccw_device->dev))
                return ERR_PTR(-ENODEV);

        adapter = kzalloc(sizeof(struct zfcp_adapter), GFP_KERNEL);
        if (!adapter) {
                put_device(&ccw_device->dev);
                return ERR_PTR(-ENOMEM);
        }

        kref_init(&adapter->ref);

        ccw_device->handler = NULL;
        adapter->ccw_device = ccw_device;

        INIT_WORK(&adapter->stat_work, _zfcp_status_read_scheduler);
        INIT_DELAYED_WORK(&adapter->scan_work, zfcp_fc_scan_ports);
        INIT_WORK(&adapter->ns_up_work, zfcp_fc_sym_name_update);

        adapter->next_port_scan = jiffies;

        if (zfcp_qdio_setup(adapter))
                goto failed;

        if (zfcp_allocate_low_mem_buffers(adapter))
                goto failed;

        adapter->req_list = zfcp_reqlist_alloc();
        if (!adapter->req_list)
                goto failed;

        if (zfcp_dbf_adapter_register(adapter))
                goto failed;

        if (zfcp_setup_adapter_work_queue(adapter))
                goto failed;

        if (zfcp_fc_gs_setup(adapter))
                goto failed;

        rwlock_init(&adapter->port_list_lock);
        INIT_LIST_HEAD(&adapter->port_list);

        INIT_LIST_HEAD(&adapter->events.list);
        INIT_WORK(&adapter->events.work, zfcp_fc_post_event);
        spin_lock_init(&adapter->events.list_lock);

        init_waitqueue_head(&adapter->erp_ready_wq);
        init_waitqueue_head(&adapter->erp_done_wqh);

        INIT_LIST_HEAD(&adapter->erp_ready_head);
        INIT_LIST_HEAD(&adapter->erp_running_head);

        rwlock_init(&adapter->erp_lock);
        rwlock_init(&adapter->abort_lock);

        if (zfcp_erp_thread_setup(adapter))
                goto failed;

        adapter->service_level.seq_print = zfcp_print_sl;

        dev_set_drvdata(&ccw_device->dev, adapter);

        if (sysfs_create_group(&ccw_device->dev.kobj,
                               &zfcp_sysfs_adapter_attrs))
                goto failed;

        /* report size limit per scatter-gather segment */
        adapter->dma_parms.max_segment_size = ZFCP_QDIO_SBALE_LEN;
        adapter->ccw_device->dev.dma_parms = &adapter->dma_parms;

        adapter->stat_read_buf_num = FSF_STATUS_READS_RECOM;

        if (!zfcp_scsi_adapter_register(adapter))
                return adapter;

failed:
        zfcp_adapter_unregister(adapter);
        return ERR_PTR(-ENOMEM);
}

void zfcp_adapter_unregister(struct zfcp_adapter *adapter)
{
        struct ccw_device *cdev = adapter->ccw_device;

        cancel_delayed_work_sync(&adapter->scan_work);
        cancel_work_sync(&adapter->stat_work);
        cancel_work_sync(&adapter->ns_up_work);
        zfcp_destroy_adapter_work_queue(adapter);

        zfcp_fc_wka_ports_force_offline(adapter->gs);
        zfcp_scsi_adapter_unregister(adapter);
        sysfs_remove_group(&cdev->dev.kobj, &zfcp_sysfs_adapter_attrs);

        zfcp_erp_thread_kill(adapter);
        zfcp_dbf_adapter_unregister(adapter);
        zfcp_qdio_destroy(adapter->qdio);

        zfcp_ccw_adapter_put(adapter); /* final put to release */
}

/**
 * zfcp_adapter_release - remove the adapter from the resource list
 * @ref: pointer to struct kref
 * locks:       adapter list write lock is assumed to be held by caller
 */
void zfcp_adapter_release(struct kref *ref)
{
        struct zfcp_adapter *adapter = container_of(ref, struct zfcp_adapter,
                                                    ref);
        struct ccw_device *cdev = adapter->ccw_device;

        dev_set_drvdata(&adapter->ccw_device->dev, NULL);
        zfcp_fc_gs_destroy(adapter);
        zfcp_free_low_mem_buffers(adapter);
        kfree(adapter->req_list);
        kfree(adapter->fc_stats);
        kfree(adapter->stats_reset_data);
        kfree(adapter);
        put_device(&cdev->dev);
}

/**
 * zfcp_device_unregister - remove port, unit from system
 * @dev: reference to device which is to be removed
 * @grp: related reference to attribute group
 *
 * Helper function to unregister port, unit from system
 */
void zfcp_device_unregister(struct device *dev,
                            const struct attribute_group *grp)
{
        sysfs_remove_group(&dev->kobj, grp);
        device_unregister(dev);
}

static void zfcp_port_release(struct device *dev)
{
        struct zfcp_port *port = container_of(dev, struct zfcp_port, dev);

        zfcp_ccw_adapter_put(port->adapter);
        kfree(port);
}

/**
 * zfcp_port_enqueue - enqueue port to port list of adapter
 * @adapter: adapter where remote port is added
 * @wwpn: WWPN of the remote port to be enqueued
 * @status: initial status for the port
 * @d_id: destination id of the remote port to be enqueued
 * Returns: pointer to enqueued port on success, ERR_PTR on error
 *
 * All port internal structures are set up and the sysfs entry is generated.
 * d_id is used to enqueue ports with a well known address like the Directory
 * Service for nameserver lookup.
 */
struct zfcp_port *zfcp_port_enqueue(struct zfcp_adapter *adapter, u64 wwpn,
                                     u32 status, u32 d_id)
{
        struct zfcp_port *port;
        int retval = -ENOMEM;

        kref_get(&adapter->ref);

        port = zfcp_get_port_by_wwpn(adapter, wwpn);
        if (port) {
                put_device(&port->dev);
                retval = -EEXIST;
                goto err_out;
        }

        port = kzalloc(sizeof(struct zfcp_port), GFP_KERNEL);
        if (!port)
                goto err_out;

        rwlock_init(&port->unit_list_lock);
        INIT_LIST_HEAD(&port->unit_list);
        atomic_set(&port->units, 0);

        INIT_WORK(&port->gid_pn_work, zfcp_fc_port_did_lookup);
        INIT_WORK(&port->test_link_work, zfcp_fc_link_test_work);
        INIT_WORK(&port->rport_work, zfcp_scsi_rport_work);

        port->adapter = adapter;
        port->d_id = d_id;
        port->wwpn = wwpn;
        port->rport_task = RPORT_NONE;
        port->dev.parent = &adapter->ccw_device->dev;
        port->dev.release = zfcp_port_release;

        if (dev_set_name(&port->dev, "0x%016llx", (unsigned long long)wwpn)) {
                kfree(port);
                goto err_out;
        }
        retval = -EINVAL;

        if (device_register(&port->dev)) {
                put_device(&port->dev);
                goto err_out;
        }

        if (sysfs_create_group(&port->dev.kobj,
                               &zfcp_sysfs_port_attrs))
                goto err_out_put;

        write_lock_irq(&adapter->port_list_lock);
        list_add_tail(&port->list, &adapter->port_list);
        write_unlock_irq(&adapter->port_list_lock);

        atomic_set_mask(status | ZFCP_STATUS_COMMON_RUNNING, &port->status);

        return port;

err_out_put:
        device_unregister(&port->dev);
err_out:
        zfcp_ccw_adapter_put(adapter);
        return ERR_PTR(retval);
}

/**
 * zfcp_sg_free_table - free memory used by scatterlists
 * @sg: pointer to scatterlist
 * @count: number of scatterlist which are to be free'ed
 * the scatterlist are expected to reference pages always
 */
void zfcp_sg_free_table(struct scatterlist *sg, int count)
{
        int i;

        for (i = 0; i < count; i++, sg++)
                if (sg)
                        free_page((unsigned long) sg_virt(sg));
                else
                        break;
}

/**
 * zfcp_sg_setup_table - init scatterlist and allocate, assign buffers
 * @sg: pointer to struct scatterlist
 * @count: number of scatterlists which should be assigned with buffers
 * of size page
 *
 * Returns: 0 on success, -ENOMEM otherwise
 */
int zfcp_sg_setup_table(struct scatterlist *sg, int count)
{
        void *addr;
        int i;

        sg_init_table(sg, count);
        for (i = 0; i < count; i++, sg++) {
                addr = (void *) get_zeroed_page(GFP_KERNEL);
                if (!addr) {
                        zfcp_sg_free_table(sg, i);
                        return -ENOMEM;
                }
                sg_set_buf(sg, addr, PAGE_SIZE);
        }
        return 0;
}