raw3270.c

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/*
 * IBM/3270 Driver - core functions.
 *
 * Author(s):
 *   Original 3270 Code for 2.4 written by Richard Hitt (UTS Global)
 *   Rewritten for 2.5 by Martin Schwidefsky <[email protected]>
 *     Copyright IBM Corp. 2003, 2009
 */

#include <linux/module.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/wait.h>

#include <asm/ccwdev.h>
#include <asm/cio.h>
#include <asm/ebcdic.h>
#include <asm/diag.h>

#include "raw3270.h"

#include <linux/major.h>
#include <linux/kdev_t.h>
#include <linux/device.h>
#include <linux/mutex.h>

static struct class *class3270;

/* The main 3270 data structure. */
struct raw3270 {
    struct list_head list;
    struct ccw_device *cdev;
    int minor;

    short model, rows, cols;
    unsigned long flags;

    struct list_head req_queue; /* Request queue. */
    struct list_head view_list; /* List of available views. */
    struct raw3270_view *view;  /* Active view. */

    struct timer_list timer;    /* Device timer. */

    unsigned char *ascebc;      /* ascii -> ebcdic table */
    struct device *clttydev;    /* 3270-class tty device ptr */
    struct device *cltubdev;    /* 3270-class tub device ptr */

    struct raw3270_request init_request;
    unsigned char init_data[256];
};

/* raw3270->flags */
#define RAW3270_FLAGS_14BITADDR 0   /* 14-bit buffer addresses */
#define RAW3270_FLAGS_BUSY  1   /* Device busy, leave it alone */
#define RAW3270_FLAGS_ATTN  2   /* Device sent an ATTN interrupt */
#define RAW3270_FLAGS_READY 4   /* Device is useable by views */
#define RAW3270_FLAGS_CONSOLE   8   /* Device is the console. */
#define RAW3270_FLAGS_FROZEN    16  /* set if 3270 is frozen for suspend */

/* Semaphore to protect global data of raw3270 (devices, views, etc). */
static DEFINE_MUTEX(raw3270_mutex);

/* List of 3270 devices. */
static LIST_HEAD(raw3270_devices);

/*
 * Flag to indicate if the driver has been registered. Some operations
 * like waiting for the end of i/o need to be done differently as long
 * as the kernel is still starting up (console support).
 */
static int raw3270_registered;

/* Module parameters */
static bool tubxcorrect = 0;
module_param(tubxcorrect, bool, 0);

/*
 * Wait queue for device init/delete, view delete.
 */
DECLARE_WAIT_QUEUE_HEAD(raw3270_wait_queue);

/*
 * Encode array for 12 bit 3270 addresses.
 */
static unsigned char raw3270_ebcgraf[64] =  {
    0x40, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7,
    0xc8, 0xc9, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,
    0x50, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7,
    0xd8, 0xd9, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f,
    0x60, 0x61, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7,
    0xe8, 0xe9, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,
    0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7,
    0xf8, 0xf9, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f
};

void
raw3270_buffer_address(struct raw3270 *rp, char *cp, unsigned short addr)
{
    if (test_bit(RAW3270_FLAGS_14BITADDR, &rp->flags)) {
        cp[0] = (addr >> 8) & 0x3f;
        cp[1] = addr & 0xff;
    } else {
        cp[0] = raw3270_ebcgraf[(addr >> 6) & 0x3f];
        cp[1] = raw3270_ebcgraf[addr & 0x3f];
    }
}

/*
 * Allocate a new 3270 ccw request
 */
struct raw3270_request *
raw3270_request_alloc(size_t size)
{
    struct raw3270_request *rq;

    /* Allocate request structure */
    rq = kzalloc(sizeof(struct raw3270_request), GFP_KERNEL | GFP_DMA);
    if (!rq)
        return ERR_PTR(-ENOMEM);

    /* alloc output buffer. */
    if (size > 0) {
        rq->buffer = kmalloc(size, GFP_KERNEL | GFP_DMA);
        if (!rq->buffer) {
            kfree(rq);
            return ERR_PTR(-ENOMEM);
        }
    }
    rq->size = size;
    INIT_LIST_HEAD(&rq->list);

    /*
     * Setup ccw.
     */
    rq->ccw.cda = __pa(rq->buffer);
    rq->ccw.flags = CCW_FLAG_SLI;

    return rq;
}

/*
 * Free 3270 ccw request
 */
void
raw3270_request_free (struct raw3270_request *rq)
{
    kfree(rq->buffer);
    kfree(rq);
}

/*
 * Reset request to initial state.
 */
void
raw3270_request_reset(struct raw3270_request *rq)
{
    BUG_ON(!list_empty(&rq->list));
    rq->ccw.cmd_code = 0;
    rq->ccw.count = 0;
    rq->ccw.cda = __pa(rq->buffer);
    rq->ccw.flags = CCW_FLAG_SLI;
    rq->rescnt = 0;
    rq->rc = 0;
}

/*
 * Set command code to ccw of a request.
 */
void
raw3270_request_set_cmd(struct raw3270_request *rq, u8 cmd)
{
    rq->ccw.cmd_code = cmd;
}

/*
 * Add data fragment to output buffer.
 */
int
raw3270_request_add_data(struct raw3270_request *rq, void *data, size_t size)
{
    if (size + rq->ccw.count > rq->size)
        return -E2BIG;
    memcpy(rq->buffer + rq->ccw.count, data, size);
    rq->ccw.count += size;
    return 0;
}

/*
 * Set address/length pair to ccw of a request.
 */
void
raw3270_request_set_data(struct raw3270_request *rq, void *data, size_t size)
{
    rq->ccw.cda = __pa(data);
    rq->ccw.count = size;
}

/*
 * Set idal buffer to ccw of a request.
 */
void
raw3270_request_set_idal(struct raw3270_request *rq, struct idal_buffer *ib)
{
    rq->ccw.cda = __pa(ib->data);
    rq->ccw.count = ib->size;
    rq->ccw.flags |= CCW_FLAG_IDA;
}

/*
 * Stop running ccw.
 */
static int
raw3270_halt_io_nolock(struct raw3270 *rp, struct raw3270_request *rq)
{
    int retries;
    int rc;

    if (raw3270_request_final(rq))
        return 0;
    /* Check if interrupt has already been processed */
    for (retries = 0; retries < 5; retries++) {
        if (retries < 2)
            rc = ccw_device_halt(rp->cdev, (long) rq);
        else
            rc = ccw_device_clear(rp->cdev, (long) rq);
        if (rc == 0)
            break;      /* termination successful */
    }
    return rc;
}

static int
raw3270_halt_io(struct raw3270 *rp, struct raw3270_request *rq)
{
    unsigned long flags;
    int rc;

    spin_lock_irqsave(get_ccwdev_lock(rp->cdev), flags);
    rc = raw3270_halt_io_nolock(rp, rq);
    spin_unlock_irqrestore(get_ccwdev_lock(rp->cdev), flags);
    return rc;
}

/*
 * Add the request to the request queue, try to start it if the
 * 3270 device is idle. Return without waiting for end of i/o.
 */
static int
__raw3270_start(struct raw3270 *rp, struct raw3270_view *view,
        struct raw3270_request *rq)
{
    rq->view = view;
    raw3270_get_view(view);
    if (list_empty(&rp->req_queue) &&
        !test_bit(RAW3270_FLAGS_BUSY, &rp->flags)) {
        /* No other requests are on the queue. Start this one. */
        rq->rc = ccw_device_start(rp->cdev, &rq->ccw,
                           (unsigned long) rq, 0, 0);
        if (rq->rc) {
            raw3270_put_view(view);
            return rq->rc;
        }
    }
    list_add_tail(&rq->list, &rp->req_queue);
    return 0;
}

int
raw3270_start(struct raw3270_view *view, struct raw3270_request *rq)
{
    unsigned long flags;
    struct raw3270 *rp;
    int rc;

    spin_lock_irqsave(get_ccwdev_lock(view->dev->cdev), flags);
    rp = view->dev;
    if (!rp || rp->view != view ||
        test_bit(RAW3270_FLAGS_FROZEN, &rp->flags))
        rc = -EACCES;
    else if (!test_bit(RAW3270_FLAGS_READY, &rp->flags))
        rc = -ENODEV;
    else
        rc =  __raw3270_start(rp, view, rq);
    spin_unlock_irqrestore(get_ccwdev_lock(view->dev->cdev), flags);
    return rc;
}

int
raw3270_start_locked(struct raw3270_view *view, struct raw3270_request *rq)
{
    struct raw3270 *rp;
    int rc;

    rp = view->dev;
    if (!rp || rp->view != view ||
        test_bit(RAW3270_FLAGS_FROZEN, &rp->flags))
        rc = -EACCES;
    else if (!test_bit(RAW3270_FLAGS_READY, &rp->flags))
        rc = -ENODEV;
    else
        rc =  __raw3270_start(rp, view, rq);
    return rc;
}

int
raw3270_start_irq(struct raw3270_view *view, struct raw3270_request *rq)
{
    struct raw3270 *rp;

    rp = view->dev;
    rq->view = view;
    raw3270_get_view(view);
    list_add_tail(&rq->list, &rp->req_queue);
    return 0;
}

/*
 * 3270 interrupt routine, called from the ccw_device layer
 */
static void
raw3270_irq (struct ccw_device *cdev, unsigned long intparm, struct irb *irb)
{
    struct raw3270 *rp;
    struct raw3270_view *view;
    struct raw3270_request *rq;
    int rc;

    rp = dev_get_drvdata(&cdev->dev);
    if (!rp)
        return;
    rq = (struct raw3270_request *) intparm;
    view = rq ? rq->view : rp->view;

    if (IS_ERR(irb))
        rc = RAW3270_IO_RETRY;
    else if (irb->scsw.cmd.fctl & SCSW_FCTL_HALT_FUNC) {
        rq->rc = -EIO;
        rc = RAW3270_IO_DONE;
    } else if (irb->scsw.cmd.dstat == (DEV_STAT_CHN_END | DEV_STAT_DEV_END |
                       DEV_STAT_UNIT_EXCEP)) {
        /* Handle CE-DE-UE and subsequent UDE */
        set_bit(RAW3270_FLAGS_BUSY, &rp->flags);
        rc = RAW3270_IO_BUSY;
    } else if (test_bit(RAW3270_FLAGS_BUSY, &rp->flags)) {
        /* Wait for UDE if busy flag is set. */
        if (irb->scsw.cmd.dstat & DEV_STAT_DEV_END) {
            clear_bit(RAW3270_FLAGS_BUSY, &rp->flags);
            /* Got it, now retry. */
            rc = RAW3270_IO_RETRY;
        } else
            rc = RAW3270_IO_BUSY;
    } else if (view)
        rc = view->fn->intv(view, rq, irb);
    else
        rc = RAW3270_IO_DONE;

    switch (rc) {
    case RAW3270_IO_DONE:
        break;
    case RAW3270_IO_BUSY:
        /* 
         * Intervention required by the operator. We have to wait
         * for unsolicited device end.
         */
        return;
    case RAW3270_IO_RETRY:
        if (!rq)
            break;
        rq->rc = ccw_device_start(rp->cdev, &rq->ccw,
                      (unsigned long) rq, 0, 0);
        if (rq->rc == 0)
            return; /* Successfully restarted. */
        break;
    case RAW3270_IO_STOP:
        if (!rq)
            break;
        raw3270_halt_io_nolock(rp, rq);
        rq->rc = -EIO;
        break;
    default:
        BUG();
    }
    if (rq) {
        BUG_ON(list_empty(&rq->list));
        /* The request completed, remove from queue and do callback. */
        list_del_init(&rq->list);
        if (rq->callback)
            rq->callback(rq, rq->callback_data);
        /* Do put_device for get_device in raw3270_start. */
        raw3270_put_view(view);
    }
    /*
     * Try to start each request on request queue until one is
     * started successful.
     */
    while (!list_empty(&rp->req_queue)) {
        rq = list_entry(rp->req_queue.next,struct raw3270_request,list);
        rq->rc = ccw_device_start(rp->cdev, &rq->ccw,
                      (unsigned long) rq, 0, 0);
        if (rq->rc == 0)
            break;
        /* Start failed. Remove request and do callback. */
        list_del_init(&rq->list);
        if (rq->callback)
            rq->callback(rq, rq->callback_data);
        /* Do put_device for get_device in raw3270_start. */
        raw3270_put_view(view);
    }
}

/*
 * Size sensing.
 */

struct raw3270_ua { /* Query Reply structure for Usable Area */
    struct {    /* Usable Area Query Reply Base */
        short l;    /* Length of this structured field */
        char  sfid; /* 0x81 if Query Reply */
        char  qcode;    /* 0x81 if Usable Area */
        char  flags0;
        char  flags1;
        short w;    /* Width of usable area */
        short h;    /* Heigth of usavle area */
        char  units;    /* 0x00:in; 0x01:mm */
        int   xr;
        int   yr;
        char  aw;
        char  ah;
        short buffsz;   /* Character buffer size, bytes */
        char  xmin;
        char  ymin;
        char  xmax;
        char  ymax;
    } __attribute__ ((packed)) uab;
    struct {    /* Alternate Usable Area Self-Defining Parameter */
        char  l;    /* Length of this Self-Defining Parm */
        char  sdpid;    /* 0x02 if Alternate Usable Area */
        char  res;
        char  auaid;    /* 0x01 is Id for the A U A */
        short wauai;    /* Width of AUAi */
        short hauai;    /* Height of AUAi */
        char  auaunits; /* 0x00:in, 0x01:mm */
        int   auaxr;
        int   auayr;
        char  awauai;
        char  ahauai;
    } __attribute__ ((packed)) aua;
} __attribute__ ((packed));

static struct diag210 raw3270_init_diag210;
static DEFINE_MUTEX(raw3270_init_mutex);

static int
raw3270_init_irq(struct raw3270_view *view, struct raw3270_request *rq,
         struct irb *irb)
{
    /*
     * Unit-Check Processing:
     * Expect Command Reject or Intervention Required.
     */
    if (irb->scsw.cmd.dstat & DEV_STAT_UNIT_CHECK) {
        /* Request finished abnormally. */
        if (irb->ecw[0] & SNS0_INTERVENTION_REQ) {
            set_bit(RAW3270_FLAGS_BUSY, &view->dev->flags);
            return RAW3270_IO_BUSY;
        }
    }
    if (rq) {
        if (irb->scsw.cmd.dstat & DEV_STAT_UNIT_CHECK) {
            if (irb->ecw[0] & SNS0_CMD_REJECT)
                rq->rc = -EOPNOTSUPP;
            else
                rq->rc = -EIO;
        } else
            /* Request finished normally. Copy residual count. */
            rq->rescnt = irb->scsw.cmd.count;
    }
    if (irb->scsw.cmd.dstat & DEV_STAT_ATTENTION) {
        set_bit(RAW3270_FLAGS_ATTN, &view->dev->flags);
        wake_up(&raw3270_wait_queue);
    }
    return RAW3270_IO_DONE;
}

static struct raw3270_fn raw3270_init_fn = {
    .intv = raw3270_init_irq
};

static struct raw3270_view raw3270_init_view = {
    .fn = &raw3270_init_fn
};

/*
 * raw3270_wait/raw3270_wait_interruptible/__raw3270_wakeup
 * Wait for end of request. The request must have been started
 * with raw3270_start, rc = 0. The device lock may NOT have been
 * released between calling raw3270_start and raw3270_wait.
 */
static void
raw3270_wake_init(struct raw3270_request *rq, void *data)
{
    wake_up((wait_queue_head_t *) data);
}

/*
 * Special wait function that can cope with console initialization.
 */
static int
raw3270_start_init(struct raw3270 *rp, struct raw3270_view *view,
           struct raw3270_request *rq)
{
    unsigned long flags;
    int rc;

#ifdef CONFIG_TN3270_CONSOLE
    if (raw3270_registered == 0) {
        spin_lock_irqsave(get_ccwdev_lock(view->dev->cdev), flags);
        rq->callback = NULL;
        rc = __raw3270_start(rp, view, rq);
        if (rc == 0)
            while (!raw3270_request_final(rq)) {
                wait_cons_dev();
                barrier();
            }
        spin_unlock_irqrestore(get_ccwdev_lock(view->dev->cdev), flags);
        return rq->rc;
    }
#endif
    rq->callback = raw3270_wake_init;
    rq->callback_data = &raw3270_wait_queue;
    spin_lock_irqsave(get_ccwdev_lock(view->dev->cdev), flags);
    rc = __raw3270_start(rp, view, rq);
    spin_unlock_irqrestore(get_ccwdev_lock(view->dev->cdev), flags);
    if (rc)
        return rc;
    /* Now wait for the completion. */
    rc = wait_event_interruptible(raw3270_wait_queue,
                      raw3270_request_final(rq));
    if (rc == -ERESTARTSYS) {   /* Interrupted by a signal. */
        raw3270_halt_io(view->dev, rq);
        /* No wait for the halt to complete. */
        wait_event(raw3270_wait_queue, raw3270_request_final(rq));
        return -ERESTARTSYS;
    }
    return rq->rc;
}

static int
__raw3270_size_device_vm(struct raw3270 *rp)
{
    int rc, model;
    struct ccw_dev_id dev_id;

    ccw_device_get_id(rp->cdev, &dev_id);
    raw3270_init_diag210.vrdcdvno = dev_id.devno;
    raw3270_init_diag210.vrdclen = sizeof(struct diag210);
    rc = diag210(&raw3270_init_diag210);
    if (rc)
        return rc;
    model = raw3270_init_diag210.vrdccrmd;
    switch (model) {
    case 2:
        rp->model = model;
        rp->rows = 24;
        rp->cols = 80;
        break;
    case 3:
        rp->model = model;
        rp->rows = 32;
        rp->cols = 80;
        break;
    case 4:
        rp->model = model;
        rp->rows = 43;
        rp->cols = 80;
        break;
    case 5:
        rp->model = model;
        rp->rows = 27;
        rp->cols = 132;
        break;
    default:
        rc = -EOPNOTSUPP;
        break;
    }
    return rc;
}

static int
__raw3270_size_device(struct raw3270 *rp)
{
    static const unsigned char wbuf[] =
        { 0x00, 0x07, 0x01, 0xff, 0x03, 0x00, 0x81 };
    struct raw3270_ua *uap;
    int rc;

    /*
     * To determine the size of the 3270 device we need to do:
     * 1) send a 'read partition' data stream to the device
     * 2) wait for the attn interrupt that precedes the query reply
     * 3) do a read modified to get the query reply
     * To make things worse we have to cope with intervention
     * required (3270 device switched to 'stand-by') and command
     * rejects (old devices that can't do 'read partition').
     */
    memset(&rp->init_request, 0, sizeof(rp->init_request));
    memset(&rp->init_data, 0, 256);
    /* Store 'read partition' data stream to init_data */
    memcpy(&rp->init_data, wbuf, sizeof(wbuf));
    INIT_LIST_HEAD(&rp->init_request.list);
    rp->init_request.ccw.cmd_code = TC_WRITESF;
    rp->init_request.ccw.flags = CCW_FLAG_SLI;
    rp->init_request.ccw.count = sizeof(wbuf);
    rp->init_request.ccw.cda = (__u32) __pa(&rp->init_data);

    rc = raw3270_start_init(rp, &raw3270_init_view, &rp->init_request);
    if (rc)
        /* Check error cases: -ERESTARTSYS, -EIO and -EOPNOTSUPP */
        return rc;

    /* Wait for attention interrupt. */
#ifdef CONFIG_TN3270_CONSOLE
    if (raw3270_registered == 0) {
        unsigned long flags;

        spin_lock_irqsave(get_ccwdev_lock(rp->cdev), flags);
        while (!test_and_clear_bit(RAW3270_FLAGS_ATTN, &rp->flags))
            wait_cons_dev();
        spin_unlock_irqrestore(get_ccwdev_lock(rp->cdev), flags);
    } else
#endif
        rc = wait_event_interruptible(raw3270_wait_queue,
            test_and_clear_bit(RAW3270_FLAGS_ATTN, &rp->flags));
    if (rc)
        return rc;

    /*
     * The device accepted the 'read partition' command. Now
     * set up a read ccw and issue it.
     */
    rp->init_request.ccw.cmd_code = TC_READMOD;
    rp->init_request.ccw.flags = CCW_FLAG_SLI;
    rp->init_request.ccw.count = sizeof(rp->init_data);
    rp->init_request.ccw.cda = (__u32) __pa(rp->init_data);
    rc = raw3270_start_init(rp, &raw3270_init_view, &rp->init_request);
    if (rc)
        return rc;
    /* Got a Query Reply */
    uap = (struct raw3270_ua *) (rp->init_data + 1);
    /* Paranoia check. */
    if (rp->init_data[0] != 0x88 || uap->uab.qcode != 0x81)
        return -EOPNOTSUPP;
    /* Copy rows/columns of default Usable Area */
    rp->rows = uap->uab.h;
    rp->cols = uap->uab.w;
    /* Check for 14 bit addressing */
    if ((uap->uab.flags0 & 0x0d) == 0x01)
        set_bit(RAW3270_FLAGS_14BITADDR, &rp->flags);
    /* Check for Alternate Usable Area */
    if (uap->uab.l == sizeof(struct raw3270_ua) &&
        uap->aua.sdpid == 0x02) {
        rp->rows = uap->aua.hauai;
        rp->cols = uap->aua.wauai;
    }
    return 0;
}

static int
raw3270_size_device(struct raw3270 *rp)
{
    int rc;

    mutex_lock(&raw3270_init_mutex);
    rp->view = &raw3270_init_view;
    raw3270_init_view.dev = rp;
    if (MACHINE_IS_VM)
        rc = __raw3270_size_device_vm(rp);
    else
        rc = __raw3270_size_device(rp);
    raw3270_init_view.dev = NULL;
    rp->view = NULL;
    mutex_unlock(&raw3270_init_mutex);
    if (rc == 0) {  /* Found something. */
        /* Try to find a model. */
        rp->model = 0;
        if (rp->rows == 24 && rp->cols == 80)
            rp->model = 2;
        if (rp->rows == 32 && rp->cols == 80)
            rp->model = 3;
        if (rp->rows == 43 && rp->cols == 80)
            rp->model = 4;
        if (rp->rows == 27 && rp->cols == 132)
            rp->model = 5;
    } else {
        /* Couldn't detect size. Use default model 2. */
        rp->model = 2;
        rp->rows = 24;
        rp->cols = 80;
        return 0;
    }
    return rc;
}

static int
raw3270_reset_device(struct raw3270 *rp)
{
    int rc;

    mutex_lock(&raw3270_init_mutex);
    memset(&rp->init_request, 0, sizeof(rp->init_request));
    memset(&rp->init_data, 0, sizeof(rp->init_data));
    /* Store reset data stream to init_data/init_request */
    rp->init_data[0] = TW_KR;
    INIT_LIST_HEAD(&rp->init_request.list);
    rp->init_request.ccw.cmd_code = TC_EWRITEA;
    rp->init_request.ccw.flags = CCW_FLAG_SLI;
    rp->init_request.ccw.count = 1;
    rp->init_request.ccw.cda = (__u32) __pa(rp->init_data);
    rp->view = &raw3270_init_view;
    raw3270_init_view.dev = rp;
    rc = raw3270_start_init(rp, &raw3270_init_view, &rp->init_request);
    raw3270_init_view.dev = NULL;
    rp->view = NULL;
    mutex_unlock(&raw3270_init_mutex);
    return rc;
}

int
raw3270_reset(struct raw3270_view *view)
{
    struct raw3270 *rp;
    int rc;

    rp = view->dev;
    if (!rp || rp->view != view ||
        test_bit(RAW3270_FLAGS_FROZEN, &rp->flags))
        rc = -EACCES;
    else if (!test_bit(RAW3270_FLAGS_READY, &rp->flags))
        rc = -ENODEV;
    else
        rc = raw3270_reset_device(view->dev);
    return rc;
}

/*
 * Setup new 3270 device.
 */
static int
raw3270_setup_device(struct ccw_device *cdev, struct raw3270 *rp, char *ascebc)
{
    struct list_head *l;
    struct raw3270 *tmp;
    int minor;

    memset(rp, 0, sizeof(struct raw3270));
    /* Copy ebcdic -> ascii translation table. */
    memcpy(ascebc, _ascebc, 256);
    if (tubxcorrect) {
        /* correct brackets and circumflex */
        ascebc['['] = 0xad;
        ascebc[']'] = 0xbd;
        ascebc['^'] = 0xb0;
    }
    rp->ascebc = ascebc;

    /* Set defaults. */
    rp->rows = 24;
    rp->cols = 80;

    INIT_LIST_HEAD(&rp->req_queue);
    INIT_LIST_HEAD(&rp->view_list);

    /*
     * Add device to list and find the smallest unused minor
     * number for it. Note: there is no device with minor 0,
     * see special case for fs3270.c:fs3270_open().
     */
    mutex_lock(&raw3270_mutex);
    /* Keep the list sorted. */
    minor = RAW3270_FIRSTMINOR;
    rp->minor = -1;
    list_for_each(l, &raw3270_devices) {
        tmp = list_entry(l, struct raw3270, list);
        if (tmp->minor > minor) {
            rp->minor = minor;
            __list_add(&rp->list, l->prev, l);
            break;
        }
        minor++;
    }
    if (rp->minor == -1 && minor < RAW3270_MAXDEVS + RAW3270_FIRSTMINOR) {
        rp->minor = minor;
        list_add_tail(&rp->list, &raw3270_devices);
    }
    mutex_unlock(&raw3270_mutex);
    /* No free minor number? Then give up. */
    if (rp->minor == -1)
        return -EUSERS;
    rp->cdev = cdev;
    dev_set_drvdata(&cdev->dev, rp);
    cdev->handler = raw3270_irq;
    return 0;
}

#ifdef CONFIG_TN3270_CONSOLE
/*
 * Setup 3270 device configured as console.
 */
struct raw3270 __init *raw3270_setup_console(struct ccw_device *cdev)
{
    struct raw3270 *rp;
    char *ascebc;
    int rc;

    rp = kzalloc(sizeof(struct raw3270), GFP_KERNEL | GFP_DMA);
    ascebc = kzalloc(256, GFP_KERNEL);
    rc = raw3270_setup_device(cdev, rp, ascebc);
    if (rc)
        return ERR_PTR(rc);
    set_bit(RAW3270_FLAGS_CONSOLE, &rp->flags);
    rc = raw3270_reset_device(rp);
    if (rc)
        return ERR_PTR(rc);
    rc = raw3270_size_device(rp);
    if (rc)
        return ERR_PTR(rc);
    rc = raw3270_reset_device(rp);
    if (rc)
        return ERR_PTR(rc);
    set_bit(RAW3270_FLAGS_READY, &rp->flags);
    return rp;
}

void
raw3270_wait_cons_dev(struct raw3270 *rp)
{
    unsigned long flags;

    spin_lock_irqsave(get_ccwdev_lock(rp->cdev), flags);
    wait_cons_dev();
    spin_unlock_irqrestore(get_ccwdev_lock(rp->cdev), flags);
}

#endif

/*
 * Create a 3270 device structure.
 */
static struct raw3270 *
raw3270_create_device(struct ccw_device *cdev)
{
    struct raw3270 *rp;
    char *ascebc;
    int rc;

    rp = kmalloc(sizeof(struct raw3270), GFP_KERNEL | GFP_DMA);
    if (!rp)
        return ERR_PTR(-ENOMEM);
    ascebc = kmalloc(256, GFP_KERNEL);
    if (!ascebc) {
        kfree(rp);
        return ERR_PTR(-ENOMEM);
    }
    rc = raw3270_setup_device(cdev, rp, ascebc);
    if (rc) {
        kfree(rp->ascebc);
        kfree(rp);
        rp = ERR_PTR(rc);
    }
    /* Get reference to ccw_device structure. */
    get_device(&cdev->dev);
    return rp;
}

/*
 * Activate a view.
 */
int
raw3270_activate_view(struct raw3270_view *view)
{
    struct raw3270 *rp;
    struct raw3270_view *oldview, *nv;
    unsigned long flags;
    int rc;

    rp = view->dev;
    if (!rp)
        return -ENODEV;
    spin_lock_irqsave(get_ccwdev_lock(rp->cdev), flags);
    if (rp->view == view)
        rc = 0;
    else if (!test_bit(RAW3270_FLAGS_READY, &rp->flags))
        rc = -ENODEV;
    else if (test_bit(RAW3270_FLAGS_FROZEN, &rp->flags))
        rc = -EACCES;
    else {
        oldview = NULL;
        if (rp->view) {
            oldview = rp->view;
            oldview->fn->deactivate(oldview);
        }
        rp->view = view;
        rc = view->fn->activate(view);
        if (rc) {
            /* Didn't work. Try to reactivate the old view. */
            rp->view = oldview;
            if (!oldview || oldview->fn->activate(oldview) != 0) {
                /* Didn't work as well. Try any other view. */
                list_for_each_entry(nv, &rp->view_list, list)
                    if (nv != view && nv != oldview) {
                        rp->view = nv;
                        if (nv->fn->activate(nv) == 0)
                            break;
                        rp->view = NULL;
                    }
            }
        }
    }
    spin_unlock_irqrestore(get_ccwdev_lock(rp->cdev), flags);
    return rc;
}

/*
 * Deactivate current view.
 */
void
raw3270_deactivate_view(struct raw3270_view *view)
{
    unsigned long flags;
    struct raw3270 *rp;

    rp = view->dev;
    if (!rp)
        return;
    spin_lock_irqsave(get_ccwdev_lock(rp->cdev), flags);
    if (rp->view == view) {
        view->fn->deactivate(view);
        rp->view = NULL;
        /* Move deactivated view to end of list. */
        list_del_init(&view->list);
        list_add_tail(&view->list, &rp->view_list);
        /* Try to activate another view. */
        if (test_bit(RAW3270_FLAGS_READY, &rp->flags) &&
            !test_bit(RAW3270_FLAGS_FROZEN, &rp->flags)) {
            list_for_each_entry(view, &rp->view_list, list) {
                rp->view = view;
                if (view->fn->activate(view) == 0)
                    break;
                rp->view = NULL;
            }
        }
    }
    spin_unlock_irqrestore(get_ccwdev_lock(rp->cdev), flags);
}

/*
 * Add view to device with minor "minor".
 */
int
raw3270_add_view(struct raw3270_view *view, struct raw3270_fn *fn, int minor)
{
    unsigned long flags;
    struct raw3270 *rp;
    int rc;

    if (minor <= 0)
        return -ENODEV;
    mutex_lock(&raw3270_mutex);
    rc = -ENODEV;
    list_for_each_entry(rp, &raw3270_devices, list) {
        if (rp->minor != minor)
            continue;
        spin_lock_irqsave(get_ccwdev_lock(rp->cdev), flags);
        if (test_bit(RAW3270_FLAGS_READY, &rp->flags)) {
            atomic_set(&view->ref_count, 2);
            view->dev = rp;
            view->fn = fn;
            view->model = rp->model;
            view->rows = rp->rows;
            view->cols = rp->cols;
            view->ascebc = rp->ascebc;
            spin_lock_init(&view->lock);
            list_add(&view->list, &rp->view_list);
            rc = 0;
        }
        spin_unlock_irqrestore(get_ccwdev_lock(rp->cdev), flags);
        break;
    }
    mutex_unlock(&raw3270_mutex);
    return rc;
}

/*
 * Find specific view of device with minor "minor".
 */
struct raw3270_view *
raw3270_find_view(struct raw3270_fn *fn, int minor)
{
    struct raw3270 *rp;
    struct raw3270_view *view, *tmp;
    unsigned long flags;

    mutex_lock(&raw3270_mutex);
    view = ERR_PTR(-ENODEV);
    list_for_each_entry(rp, &raw3270_devices, list) {
        if (rp->minor != minor)
            continue;
        spin_lock_irqsave(get_ccwdev_lock(rp->cdev), flags);
        if (test_bit(RAW3270_FLAGS_READY, &rp->flags)) {
            view = ERR_PTR(-ENOENT);
            list_for_each_entry(tmp, &rp->view_list, list) {
                if (tmp->fn == fn) {
                    raw3270_get_view(tmp);
                    view = tmp;
                    break;
                }
            }
        }
        spin_unlock_irqrestore(get_ccwdev_lock(rp->cdev), flags);
        break;
    }
    mutex_unlock(&raw3270_mutex);
    return view;
}

/*
 * Remove view from device and free view structure via call to view->fn->free.
 */
void
raw3270_del_view(struct raw3270_view *view)
{
    unsigned long flags;
    struct raw3270 *rp;
    struct raw3270_view *nv;

    rp = view->dev;
    spin_lock_irqsave(get_ccwdev_lock(rp->cdev), flags);
    if (rp->view == view) {
        view->fn->deactivate(view);
        rp->view = NULL;
    }
    list_del_init(&view->list);
    if (!rp->view && test_bit(RAW3270_FLAGS_READY, &rp->flags) &&
        !test_bit(RAW3270_FLAGS_FROZEN, &rp->flags)) {
        /* Try to activate another view. */
        list_for_each_entry(nv, &rp->view_list, list) {
            if (nv->fn->activate(nv) == 0) {
                rp->view = nv;
                break;
            }
        }
    }
    spin_unlock_irqrestore(get_ccwdev_lock(rp->cdev), flags);
    /* Wait for reference counter to drop to zero. */
    atomic_dec(&view->ref_count);
    wait_event(raw3270_wait_queue, atomic_read(&view->ref_count) == 0);
    if (view->fn->free)
        view->fn->free(view);
}

/*
 * Remove a 3270 device structure.
 */
static void
raw3270_delete_device(struct raw3270 *rp)
{
    struct ccw_device *cdev;

    /* Remove from device chain. */
    mutex_lock(&raw3270_mutex);
    if (rp->clttydev && !IS_ERR(rp->clttydev))
        device_destroy(class3270, MKDEV(IBM_TTY3270_MAJOR, rp->minor));
    if (rp->cltubdev && !IS_ERR(rp->cltubdev))
        device_destroy(class3270, MKDEV(IBM_FS3270_MAJOR, rp->minor));
    list_del_init(&rp->list);
    mutex_unlock(&raw3270_mutex);

    /* Disconnect from ccw_device. */
    cdev = rp->cdev;
    rp->cdev = NULL;
    dev_set_drvdata(&cdev->dev, NULL);
    cdev->handler = NULL;

    /* Put ccw_device structure. */
    put_device(&cdev->dev);

    /* Now free raw3270 structure. */
    kfree(rp->ascebc);
    kfree(rp);
}

static int
raw3270_probe (struct ccw_device *cdev)
{
    return 0;
}

/*
 * Additional attributes for a 3270 device
 */
static ssize_t
raw3270_model_show(struct device *dev, struct device_attribute *attr, char *buf)
{
    return snprintf(buf, PAGE_SIZE, "%i\n",
            ((struct raw3270 *) dev_get_drvdata(dev))->model);
}
static DEVICE_ATTR(model, 0444, raw3270_model_show, NULL);

static ssize_t
raw3270_rows_show(struct device *dev, struct device_attribute *attr, char *buf)
{
    return snprintf(buf, PAGE_SIZE, "%i\n",
            ((struct raw3270 *) dev_get_drvdata(dev))->rows);
}
static DEVICE_ATTR(rows, 0444, raw3270_rows_show, NULL);

static ssize_t
raw3270_columns_show(struct device *dev, struct device_attribute *attr, char *buf)
{
    return snprintf(buf, PAGE_SIZE, "%i\n",
            ((struct raw3270 *) dev_get_drvdata(dev))->cols);
}
static DEVICE_ATTR(columns, 0444, raw3270_columns_show, NULL);

static struct attribute * raw3270_attrs[] = {
    &dev_attr_model.attr,
    &dev_attr_rows.attr,
    &dev_attr_columns.attr,
    NULL,
};

static struct attribute_group raw3270_attr_group = {
    .attrs = raw3270_attrs,
};

static int raw3270_create_attributes(struct raw3270 *rp)
{
    int rc;

    rc = sysfs_create_group(&rp->cdev->dev.kobj, &raw3270_attr_group);
    if (rc)
        goto out;

    rp->clttydev = device_create(class3270, &rp->cdev->dev,
                     MKDEV(IBM_TTY3270_MAJOR, rp->minor), NULL,
                     "tty%s", dev_name(&rp->cdev->dev));
    if (IS_ERR(rp->clttydev)) {
        rc = PTR_ERR(rp->clttydev);
        goto out_ttydev;
    }

    rp->cltubdev = device_create(class3270, &rp->cdev->dev,
                     MKDEV(IBM_FS3270_MAJOR, rp->minor), NULL,
                     "tub%s", dev_name(&rp->cdev->dev));
    if (!IS_ERR(rp->cltubdev))
        goto out;

    rc = PTR_ERR(rp->cltubdev);
    device_destroy(class3270, MKDEV(IBM_TTY3270_MAJOR, rp->minor));

out_ttydev:
    sysfs_remove_group(&rp->cdev->dev.kobj, &raw3270_attr_group);
out:
    return rc;
}

/*
 * Notifier for device addition/removal
 */
struct raw3270_notifier {
    struct list_head list;
    void (*notifier)(int, int);
};

static LIST_HEAD(raw3270_notifier);

int raw3270_register_notifier(void (*notifier)(int, int))
{
    struct raw3270_notifier *np;
    struct raw3270 *rp;

    np = kmalloc(sizeof(struct raw3270_notifier), GFP_KERNEL);
    if (!np)
        return -ENOMEM;
    np->notifier = notifier;
    mutex_lock(&raw3270_mutex);
    list_add_tail(&np->list, &raw3270_notifier);
    list_for_each_entry(rp, &raw3270_devices, list) {
        get_device(&rp->cdev->dev);
        notifier(rp->minor, 1);
    }
    mutex_unlock(&raw3270_mutex);
    return 0;
}

void raw3270_unregister_notifier(void (*notifier)(int, int))
{
    struct raw3270_notifier *np;

    mutex_lock(&raw3270_mutex);
    list_for_each_entry(np, &raw3270_notifier, list)
        if (np->notifier == notifier) {
            list_del(&np->list);
            kfree(np);
            break;
        }
    mutex_unlock(&raw3270_mutex);
}

/*
 * Set 3270 device online.
 */
static int
raw3270_set_online (struct ccw_device *cdev)
{
    struct raw3270 *rp;
    struct raw3270_notifier *np;
    int rc;

    rp = raw3270_create_device(cdev);
    if (IS_ERR(rp))
        return PTR_ERR(rp);
    rc = raw3270_reset_device(rp);
    if (rc)
        goto failure;
    rc = raw3270_size_device(rp);
    if (rc)
        goto failure;
    rc = raw3270_reset_device(rp);
    if (rc)
        goto failure;
    rc = raw3270_create_attributes(rp);
    if (rc)
        goto failure;
    set_bit(RAW3270_FLAGS_READY, &rp->flags);
    mutex_lock(&raw3270_mutex);
    list_for_each_entry(np, &raw3270_notifier, list)
        np->notifier(rp->minor, 1);
    mutex_unlock(&raw3270_mutex);
    return 0;

failure:
    raw3270_delete_device(rp);
    return rc;
}

/*
 * Remove 3270 device structure.
 */
static void
raw3270_remove (struct ccw_device *cdev)
{
    unsigned long flags;
    struct raw3270 *rp;
    struct raw3270_view *v;
    struct raw3270_notifier *np;

    rp = dev_get_drvdata(&cdev->dev);
    /*
     * _remove is the opposite of _probe; it's probe that
     * should set up rp.  raw3270_remove gets entered for
     * devices even if they haven't been varied online.
     * Thus, rp may validly be NULL here.
     */
    if (rp == NULL)
        return;
    clear_bit(RAW3270_FLAGS_READY, &rp->flags);

    sysfs_remove_group(&cdev->dev.kobj, &raw3270_attr_group);

    /* Deactivate current view and remove all views. */
    spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
    if (rp->view) {
        rp->view->fn->deactivate(rp->view);
        rp->view = NULL;
    }
    while (!list_empty(&rp->view_list)) {
        v = list_entry(rp->view_list.next, struct raw3270_view, list);
        if (v->fn->release)
            v->fn->release(v);
        spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
        raw3270_del_view(v);
        spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
    }
    spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);

    mutex_lock(&raw3270_mutex);
    list_for_each_entry(np, &raw3270_notifier, list)
        np->notifier(rp->minor, 0);
    mutex_unlock(&raw3270_mutex);

    /* Reset 3270 device. */
    raw3270_reset_device(rp);
    /* And finally remove it. */
    raw3270_delete_device(rp);
}

/*
 * Set 3270 device offline.
 */
static int
raw3270_set_offline (struct ccw_device *cdev)
{
    struct raw3270 *rp;

    rp = dev_get_drvdata(&cdev->dev);
    if (test_bit(RAW3270_FLAGS_CONSOLE, &rp->flags))
        return -EBUSY;
    raw3270_remove(cdev);
    return 0;
}

static int raw3270_pm_stop(struct ccw_device *cdev)
{
    struct raw3270 *rp;
    struct raw3270_view *view;
    unsigned long flags;

    rp = dev_get_drvdata(&cdev->dev);
    if (!rp)
        return 0;
    spin_lock_irqsave(get_ccwdev_lock(rp->cdev), flags);
    if (rp->view)
        rp->view->fn->deactivate(rp->view);
    if (!test_bit(RAW3270_FLAGS_CONSOLE, &rp->flags)) {
        /*
         * Release tty and fullscreen for all non-console
         * devices.
         */
        list_for_each_entry(view, &rp->view_list, list) {
            if (view->fn->release)
                view->fn->release(view);
        }
    }
    set_bit(RAW3270_FLAGS_FROZEN, &rp->flags);
    spin_unlock_irqrestore(get_ccwdev_lock(rp->cdev), flags);
    return 0;
}

static int raw3270_pm_start(struct ccw_device *cdev)
{
    struct raw3270 *rp;
    unsigned long flags;

    rp = dev_get_drvdata(&cdev->dev);
    if (!rp)
        return 0;
    spin_lock_irqsave(get_ccwdev_lock(rp->cdev), flags);
    clear_bit(RAW3270_FLAGS_FROZEN, &rp->flags);
    if (rp->view)
        rp->view->fn->activate(rp->view);
    spin_unlock_irqrestore(get_ccwdev_lock(rp->cdev), flags);
    return 0;
}

void raw3270_pm_unfreeze(struct raw3270_view *view)
{
#ifdef CONFIG_TN3270_CONSOLE
    struct raw3270 *rp;

    rp = view->dev;
    if (rp && test_bit(RAW3270_FLAGS_FROZEN, &rp->flags))
        ccw_device_force_console();
#endif
}

static struct ccw_device_id raw3270_id[] = {
    { CCW_DEVICE(0x3270, 0) },
    { CCW_DEVICE(0x3271, 0) },
    { CCW_DEVICE(0x3272, 0) },
    { CCW_DEVICE(0x3273, 0) },
    { CCW_DEVICE(0x3274, 0) },
    { CCW_DEVICE(0x3275, 0) },
    { CCW_DEVICE(0x3276, 0) },
    { CCW_DEVICE(0x3277, 0) },
    { CCW_DEVICE(0x3278, 0) },
    { CCW_DEVICE(0x3279, 0) },
    { CCW_DEVICE(0x3174, 0) },
    { /* end of list */ },
};

static struct ccw_driver raw3270_ccw_driver = {
    .driver = {
        .name   = "3270",
        .owner  = THIS_MODULE,
    },
    .ids        = raw3270_id,
    .probe      = &raw3270_probe,
    .remove     = &raw3270_remove,
    .set_online = &raw3270_set_online,
    .set_offline    = &raw3270_set_offline,
    .freeze     = &raw3270_pm_stop,
    .thaw       = &raw3270_pm_start,
    .restore    = &raw3270_pm_start,
    .int_class  = IOINT_C70,
};

static int
raw3270_init(void)
{
    struct raw3270 *rp;
    int rc;

    if (raw3270_registered)
        return 0;
    raw3270_registered = 1;
    rc = ccw_driver_register(&raw3270_ccw_driver);
    if (rc == 0) {
        /* Create attributes for early (= console) device. */
        mutex_lock(&raw3270_mutex);
        class3270 = class_create(THIS_MODULE, "3270");
        list_for_each_entry(rp, &raw3270_devices, list) {
            get_device(&rp->cdev->dev);
            raw3270_create_attributes(rp);
        }
        mutex_unlock(&raw3270_mutex);
    }
    return rc;
}

static void
raw3270_exit(void)
{
    ccw_driver_unregister(&raw3270_ccw_driver);
    class_destroy(class3270);
}

MODULE_LICENSE("GPL");

module_init(raw3270_init);
module_exit(raw3270_exit);

EXPORT_SYMBOL(raw3270_request_alloc);
EXPORT_SYMBOL(raw3270_request_free);
EXPORT_SYMBOL(raw3270_request_reset);
EXPORT_SYMBOL(raw3270_request_set_cmd);
EXPORT_SYMBOL(raw3270_request_add_data);
EXPORT_SYMBOL(raw3270_request_set_data);
EXPORT_SYMBOL(raw3270_request_set_idal);
EXPORT_SYMBOL(raw3270_buffer_address);
EXPORT_SYMBOL(raw3270_add_view);
EXPORT_SYMBOL(raw3270_del_view);
EXPORT_SYMBOL(raw3270_find_view);
EXPORT_SYMBOL(raw3270_activate_view);
EXPORT_SYMBOL(raw3270_deactivate_view);
EXPORT_SYMBOL(raw3270_start);
EXPORT_SYMBOL(raw3270_start_locked);
EXPORT_SYMBOL(raw3270_start_irq);
EXPORT_SYMBOL(raw3270_reset);
EXPORT_SYMBOL(raw3270_register_notifier);
EXPORT_SYMBOL(raw3270_unregister_notifier);
EXPORT_SYMBOL(raw3270_wait_queue);