con3215.c

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/*
 * 3215 line mode terminal driver.
 *
 * Copyright IBM Corp. 1999, 2009
 * Author(s): Martin Schwidefsky <[email protected]>
 *
 * Updated:
 *  Aug-2000: Added tab support
 *        Dan Morrison, IBM Corporation <[email protected]>
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kdev_t.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/vt_kern.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/interrupt.h>
#include <linux/err.h>
#include <linux/reboot.h>
#include <linux/serial.h> /* ASYNC_* flags */
#include <linux/slab.h>
#include <asm/ccwdev.h>
#include <asm/cio.h>
#include <asm/io.h>
#include <asm/ebcdic.h>
#include <asm/uaccess.h>
#include <asm/delay.h>
#include <asm/cpcmd.h>
#include <asm/setup.h>

#include "ctrlchar.h"

#define NR_3215         1
#define NR_3215_REQ     (4*NR_3215)
#define RAW3215_BUFFER_SIZE 65536     /* output buffer size */
#define RAW3215_INBUF_SIZE  256       /* input buffer size */
#define RAW3215_MIN_SPACE   128       /* minimum free space for wakeup */
#define RAW3215_MIN_WRITE   1024      /* min. length for immediate output */
#define RAW3215_MAX_BYTES   3968      /* max. bytes to write with one ssch */
#define RAW3215_MAX_NEWLINE 50        /* max. lines to write with one ssch */
#define RAW3215_NR_CCWS     3
#define RAW3215_TIMEOUT     HZ/10     /* time for delayed output */

#define RAW3215_WORKING     4         /* set if a request is being worked on */
#define RAW3215_THROTTLED   8         /* set if reading is disabled */
#define RAW3215_STOPPED     16        /* set if writing is disabled */
#define RAW3215_TIMER_RUNS  64        /* set if the output delay timer is on */
#define RAW3215_FLUSHING    128       /* set to flush buffer (no delay) */

#define TAB_STOP_SIZE       8         /* tab stop size */

/*
 * Request types for a 3215 device
 */
enum raw3215_type {
    RAW3215_FREE, RAW3215_READ, RAW3215_WRITE
};

/*
 * Request structure for a 3215 device
 */
struct raw3215_req {
    enum raw3215_type type;       /* type of the request */
    int start, len;           /* start index & len in output buffer */
    int delayable;            /* indication to wait for more data */
    int residual;             /* residual count for read request */
    struct ccw1 ccws[RAW3215_NR_CCWS]; /* space for the channel program */
    struct raw3215_info *info;    /* pointer to main structure */
    struct raw3215_req *next;     /* pointer to next request */
} __attribute__ ((aligned(8)));

struct raw3215_info {
    struct tty_port port;
    struct ccw_device *cdev;      /* device for tty driver */
    spinlock_t *lock;         /* pointer to irq lock */
    int flags;            /* state flags */
    char *buffer;             /* pointer to output buffer */
    char *inbuf;              /* pointer to input buffer */
    int head;             /* first free byte in output buffer */
    int count;            /* number of bytes in output buffer */
    int written;              /* number of bytes in write requests */
    struct raw3215_req *queued_read; /* pointer to queued read requests */
    struct raw3215_req *queued_write;/* pointer to queued write requests */
    struct tasklet_struct tlet;   /* tasklet to invoke tty_wakeup */
    wait_queue_head_t empty_wait; /* wait queue for flushing */
    struct timer_list timer;      /* timer for delayed output */
    int line_pos;             /* position on the line (for tabs) */
    char ubuffer[80];         /* copy_from_user buffer */
};

/* array of 3215 devices structures */
static struct raw3215_info *raw3215[NR_3215];
/* spinlock to protect the raw3215 array */
static DEFINE_SPINLOCK(raw3215_device_lock);
/* list of free request structures */
static struct raw3215_req *raw3215_freelist;
/* spinlock to protect free list */
static spinlock_t raw3215_freelist_lock;

static struct tty_driver *tty3215_driver;

/*
 * Get a request structure from the free list
 */
static inline struct raw3215_req *raw3215_alloc_req(void)
{
    struct raw3215_req *req;
    unsigned long flags;

    spin_lock_irqsave(&raw3215_freelist_lock, flags);
    req = raw3215_freelist;
    raw3215_freelist = req->next;
    spin_unlock_irqrestore(&raw3215_freelist_lock, flags);
    return req;
}

/*
 * Put a request structure back to the free list
 */
static inline void raw3215_free_req(struct raw3215_req *req)
{
    unsigned long flags;

    if (req->type == RAW3215_FREE)
        return;     /* don't free a free request */
    req->type = RAW3215_FREE;
    spin_lock_irqsave(&raw3215_freelist_lock, flags);
    req->next = raw3215_freelist;
    raw3215_freelist = req;
    spin_unlock_irqrestore(&raw3215_freelist_lock, flags);
}

/*
 * Set up a read request that reads up to 160 byte from the 3215 device.
 * If there is a queued read request it is used, but that shouldn't happen
 * because a 3215 terminal won't accept a new read before the old one is
 * completed.
 */
static void raw3215_mk_read_req(struct raw3215_info *raw)
{
    struct raw3215_req *req;
    struct ccw1 *ccw;

    /* there can only be ONE read request at a time */
    req = raw->queued_read;
    if (req == NULL) {
        /* no queued read request, use new req structure */
        req = raw3215_alloc_req();
        req->type = RAW3215_READ;
        req->info = raw;
        raw->queued_read = req;
    }

    ccw = req->ccws;
    ccw->cmd_code = 0x0A; /* read inquiry */
    ccw->flags = 0x20;    /* ignore incorrect length */
    ccw->count = 160;
    ccw->cda = (__u32) __pa(raw->inbuf);
}

/*
 * Set up a write request with the information from the main structure.
 * A ccw chain is created that writes as much as possible from the output
 * buffer to the 3215 device. If a queued write exists it is replaced by
 * the new, probably lengthened request.
 */
static void raw3215_mk_write_req(struct raw3215_info *raw)
{
    struct raw3215_req *req;
    struct ccw1 *ccw;
    int len, count, ix, lines;

    if (raw->count <= raw->written)
        return;
    /* check if there is a queued write request */
    req = raw->queued_write;
    if (req == NULL) {
        /* no queued write request, use new req structure */
        req = raw3215_alloc_req();
        req->type = RAW3215_WRITE;
        req->info = raw;
        raw->queued_write = req;
    } else {
        raw->written -= req->len;
    }

    ccw = req->ccws;
    req->start = (raw->head - raw->count + raw->written) &
             (RAW3215_BUFFER_SIZE - 1);
    /*
     * now we have to count newlines. We can at max accept
     * RAW3215_MAX_NEWLINE newlines in a single ssch due to
     * a restriction in VM
     */
    lines = 0;
    ix = req->start;
    while (lines < RAW3215_MAX_NEWLINE && ix != raw->head) {
        if (raw->buffer[ix] == 0x15)
            lines++;
        ix = (ix + 1) & (RAW3215_BUFFER_SIZE - 1);
    }
    len = ((ix - 1 - req->start) & (RAW3215_BUFFER_SIZE - 1)) + 1;
    if (len > RAW3215_MAX_BYTES)
        len = RAW3215_MAX_BYTES;
    req->len = len;
    raw->written += len;

    /* set the indication if we should try to enlarge this request */
    req->delayable = (ix == raw->head) && (len < RAW3215_MIN_WRITE);

    ix = req->start;
    while (len > 0) {
        if (ccw > req->ccws)
            ccw[-1].flags |= 0x40; /* use command chaining */
        ccw->cmd_code = 0x01; /* write, auto carrier return */
        ccw->flags = 0x20;    /* ignore incorrect length ind.  */
        ccw->cda =
            (__u32) __pa(raw->buffer + ix);
        count = len;
        if (ix + count > RAW3215_BUFFER_SIZE)
            count = RAW3215_BUFFER_SIZE - ix;
        ccw->count = count;
        len -= count;
        ix = (ix + count) & (RAW3215_BUFFER_SIZE - 1);
        ccw++;
    }
    /*
     * Add a NOP to the channel program. 3215 devices are purely
     * emulated and its much better to avoid the channel end
     * interrupt in this case.
     */
    if (ccw > req->ccws)
        ccw[-1].flags |= 0x40; /* use command chaining */
    ccw->cmd_code = 0x03; /* NOP */
    ccw->flags = 0;
    ccw->cda = 0;
    ccw->count = 1;
}

/*
 * Start a read or a write request
 */
static void raw3215_start_io(struct raw3215_info *raw)
{
    struct raw3215_req *req;
    int res;

    req = raw->queued_read;
    if (req != NULL &&
        !(raw->flags & (RAW3215_WORKING | RAW3215_THROTTLED))) {
        /* dequeue request */
        raw->queued_read = NULL;
        res = ccw_device_start(raw->cdev, req->ccws,
                       (unsigned long) req, 0, 0);
        if (res != 0) {
            /* do_IO failed, put request back to queue */
            raw->queued_read = req;
        } else {
            raw->flags |= RAW3215_WORKING;
        }
    }
    req = raw->queued_write;
    if (req != NULL &&
        !(raw->flags & (RAW3215_WORKING | RAW3215_STOPPED))) {
        /* dequeue request */
        raw->queued_write = NULL;
        res = ccw_device_start(raw->cdev, req->ccws,
                       (unsigned long) req, 0, 0);
        if (res != 0) {
            /* do_IO failed, put request back to queue */
            raw->queued_write = req;
        } else {
            raw->flags |= RAW3215_WORKING;
        }
    }
}

/*
 * Function to start a delayed output after RAW3215_TIMEOUT seconds
 */
static void raw3215_timeout(unsigned long __data)
{
    struct raw3215_info *raw = (struct raw3215_info *) __data;
    unsigned long flags;

    spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
    if (raw->flags & RAW3215_TIMER_RUNS) {
        del_timer(&raw->timer);
        raw->flags &= ~RAW3215_TIMER_RUNS;
        if (!(raw->port.flags & ASYNC_SUSPENDED)) {
            raw3215_mk_write_req(raw);
            raw3215_start_io(raw);
        }
    }
    spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
}

/*
 * Function to conditionally start an IO. A read is started immediately,
 * a write is only started immediately if the flush flag is on or the
 * amount of data is bigger than RAW3215_MIN_WRITE. If a write is not
 * done immediately a timer is started with a delay of RAW3215_TIMEOUT.
 */
static inline void raw3215_try_io(struct raw3215_info *raw)
{
    if (!(raw->port.flags & ASYNC_INITIALIZED) ||
            (raw->port.flags & ASYNC_SUSPENDED))
        return;
    if (raw->queued_read != NULL)
        raw3215_start_io(raw);
    else if (raw->queued_write != NULL) {
        if ((raw->queued_write->delayable == 0) ||
            (raw->flags & RAW3215_FLUSHING)) {
            /* execute write requests bigger than minimum size */
            raw3215_start_io(raw);
            if (raw->flags & RAW3215_TIMER_RUNS) {
                del_timer(&raw->timer);
                raw->flags &= ~RAW3215_TIMER_RUNS;
            }
        } else if (!(raw->flags & RAW3215_TIMER_RUNS)) {
            /* delay small writes */
            raw->timer.expires = RAW3215_TIMEOUT + jiffies;
            add_timer(&raw->timer);
            raw->flags |= RAW3215_TIMER_RUNS;
        }
    }
}

/*
 * Call tty_wakeup from tasklet context
 */
static void raw3215_wakeup(unsigned long data)
{
    struct raw3215_info *raw = (struct raw3215_info *) data;
    struct tty_struct *tty;

    tty = tty_port_tty_get(&raw->port);
    if (tty) {
        tty_wakeup(tty);
        tty_kref_put(tty);
    }
}

/*
 * Try to start the next IO and wake up processes waiting on the tty.
 */
static void raw3215_next_io(struct raw3215_info *raw, struct tty_struct *tty)
{
    raw3215_mk_write_req(raw);
    raw3215_try_io(raw);
    if (tty && RAW3215_BUFFER_SIZE - raw->count >= RAW3215_MIN_SPACE)
        tasklet_schedule(&raw->tlet);
}

/*
 * Interrupt routine, called from common io layer
 */
static void raw3215_irq(struct ccw_device *cdev, unsigned long intparm,
            struct irb *irb)
{
    struct raw3215_info *raw;
    struct raw3215_req *req;
    struct tty_struct *tty;
    int cstat, dstat;
    int count;

    raw = dev_get_drvdata(&cdev->dev);
    req = (struct raw3215_req *) intparm;
    tty = tty_port_tty_get(&raw->port);
    cstat = irb->scsw.cmd.cstat;
    dstat = irb->scsw.cmd.dstat;
    if (cstat != 0)
        raw3215_next_io(raw, tty);
    if (dstat & 0x01) { /* we got a unit exception */
        dstat &= ~0x01;  /* we can ignore it */
    }
    switch (dstat) {
    case 0x80:
        if (cstat != 0)
            break;
        /* Attention interrupt, someone hit the enter key */
        raw3215_mk_read_req(raw);
        raw3215_next_io(raw, tty);
        break;
    case 0x08:
    case 0x0C:
        /* Channel end interrupt. */
        if ((raw = req->info) == NULL)
            goto put_tty;        /* That shouldn't happen ... */
        if (req->type == RAW3215_READ) {
            /* store residual count, then wait for device end */
            req->residual = irb->scsw.cmd.count;
        }
        if (dstat == 0x08)
            break;
    case 0x04:
        /* Device end interrupt. */
        if ((raw = req->info) == NULL)
            goto put_tty;        /* That shouldn't happen ... */
        if (req->type == RAW3215_READ && tty != NULL) {
            unsigned int cchar;

            count = 160 - req->residual;
            EBCASC(raw->inbuf, count);
            cchar = ctrlchar_handle(raw->inbuf, count, tty);
            switch (cchar & CTRLCHAR_MASK) {
            case CTRLCHAR_SYSRQ:
                break;

            case CTRLCHAR_CTRL:
                tty_insert_flip_char(tty, cchar, TTY_NORMAL);
                tty_flip_buffer_push(tty);
                break;

            case CTRLCHAR_NONE:
                if (count < 2 ||
                    (strncmp(raw->inbuf+count-2, "\252n", 2) &&
                     strncmp(raw->inbuf+count-2, "^n", 2)) ) {
                    /* add the auto \n */
                    raw->inbuf[count] = '\n';
                    count++;
                } else
                    count -= 2;
                tty_insert_flip_string(tty, raw->inbuf, count);
                tty_flip_buffer_push(tty);
                break;
            }
        } else if (req->type == RAW3215_WRITE) {
            raw->count -= req->len;
            raw->written -= req->len;
        }
        raw->flags &= ~RAW3215_WORKING;
        raw3215_free_req(req);
        /* check for empty wait */
        if (waitqueue_active(&raw->empty_wait) &&
            raw->queued_write == NULL &&
            raw->queued_read == NULL) {
            wake_up_interruptible(&raw->empty_wait);
        }
        raw3215_next_io(raw, tty);
        break;
    default:
        /* Strange interrupt, I'll do my best to clean up */
        if (req != NULL && req->type != RAW3215_FREE) {
            if (req->type == RAW3215_WRITE) {
                raw->count -= req->len;
                raw->written -= req->len;
            }
            raw->flags &= ~RAW3215_WORKING;
            raw3215_free_req(req);
        }
        raw3215_next_io(raw, tty);
    }
put_tty:
    tty_kref_put(tty);
}

/*
 * Drop the oldest line from the output buffer.
 */
static void raw3215_drop_line(struct raw3215_info *raw)
{
    int ix;
    char ch;

    BUG_ON(raw->written != 0);
    ix = (raw->head - raw->count) & (RAW3215_BUFFER_SIZE - 1);
    while (raw->count > 0) {
        ch = raw->buffer[ix];
        ix = (ix + 1) & (RAW3215_BUFFER_SIZE - 1);
        raw->count--;
        if (ch == 0x15)
            break;
    }
    raw->head = ix;
}

/*
 * Wait until length bytes are available int the output buffer.
 * Has to be called with the s390irq lock held. Can be called
 * disabled.
 */
static void raw3215_make_room(struct raw3215_info *raw, unsigned int length)
{
    while (RAW3215_BUFFER_SIZE - raw->count < length) {
        /* While console is frozen for suspend we have no other
         * choice but to drop message from the buffer to make
         * room for even more messages. */
        if (raw->port.flags & ASYNC_SUSPENDED) {
            raw3215_drop_line(raw);
            continue;
        }
        /* there might be a request pending */
        raw->flags |= RAW3215_FLUSHING;
        raw3215_mk_write_req(raw);
        raw3215_try_io(raw);
        raw->flags &= ~RAW3215_FLUSHING;
#ifdef CONFIG_TN3215_CONSOLE
        wait_cons_dev();
#endif
        /* Enough room freed up ? */
        if (RAW3215_BUFFER_SIZE - raw->count >= length)
            break;
        /* there might be another cpu waiting for the lock */
        spin_unlock(get_ccwdev_lock(raw->cdev));
        udelay(100);
        spin_lock(get_ccwdev_lock(raw->cdev));
    }
}

/*
 * String write routine for 3215 devices
 */
static void raw3215_write(struct raw3215_info *raw, const char *str,
              unsigned int length)
{
    unsigned long flags;
    int c, count;

    while (length > 0) {
        spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
        count = (length > RAW3215_BUFFER_SIZE) ?
                         RAW3215_BUFFER_SIZE : length;
        length -= count;

        raw3215_make_room(raw, count);

        /* copy string to output buffer and convert it to EBCDIC */
        while (1) {
            c = min_t(int, count,
                  min(RAW3215_BUFFER_SIZE - raw->count,
                      RAW3215_BUFFER_SIZE - raw->head));
            if (c <= 0)
                break;
            memcpy(raw->buffer + raw->head, str, c);
            ASCEBC(raw->buffer + raw->head, c);
            raw->head = (raw->head + c) & (RAW3215_BUFFER_SIZE - 1);
            raw->count += c;
            raw->line_pos += c;
            str += c;
            count -= c;
        }
        if (!(raw->flags & RAW3215_WORKING)) {
            raw3215_mk_write_req(raw);
            /* start or queue request */
            raw3215_try_io(raw);
        }
        spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
    }
}

/*
 * Put character routine for 3215 devices
 */
static void raw3215_putchar(struct raw3215_info *raw, unsigned char ch)
{
    unsigned long flags;
    unsigned int length, i;

    spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
    if (ch == '\t') {
        length = TAB_STOP_SIZE - (raw->line_pos%TAB_STOP_SIZE);
        raw->line_pos += length;
        ch = ' ';
    } else if (ch == '\n') {
        length = 1;
        raw->line_pos = 0;
    } else {
        length = 1;
        raw->line_pos++;
    }
    raw3215_make_room(raw, length);

    for (i = 0; i < length; i++) {
        raw->buffer[raw->head] = (char) _ascebc[(int) ch];
        raw->head = (raw->head + 1) & (RAW3215_BUFFER_SIZE - 1);
        raw->count++;
    }
    if (!(raw->flags & RAW3215_WORKING)) {
        raw3215_mk_write_req(raw);
        /* start or queue request */
        raw3215_try_io(raw);
    }
    spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
}

/*
 * Flush routine, it simply sets the flush flag and tries to start
 * pending IO.
 */
static void raw3215_flush_buffer(struct raw3215_info *raw)
{
    unsigned long flags;

    spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
    if (raw->count > 0) {
        raw->flags |= RAW3215_FLUSHING;
        raw3215_try_io(raw);
        raw->flags &= ~RAW3215_FLUSHING;
    }
    spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
}

/*
 * Fire up a 3215 device.
 */
static int raw3215_startup(struct raw3215_info *raw)
{
    unsigned long flags;

    if (raw->port.flags & ASYNC_INITIALIZED)
        return 0;
    raw->line_pos = 0;
    raw->port.flags |= ASYNC_INITIALIZED;
    spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
    raw3215_try_io(raw);
    spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);

    return 0;
}

/*
 * Shutdown a 3215 device.
 */
static void raw3215_shutdown(struct raw3215_info *raw)
{
    DECLARE_WAITQUEUE(wait, current);
    unsigned long flags;

    if (!(raw->port.flags & ASYNC_INITIALIZED))
        return;
    /* Wait for outstanding requests, then free irq */
    spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
    if ((raw->flags & RAW3215_WORKING) ||
        raw->queued_write != NULL ||
        raw->queued_read != NULL) {
        raw->port.flags |= ASYNC_CLOSING;
        add_wait_queue(&raw->empty_wait, &wait);
        set_current_state(TASK_INTERRUPTIBLE);
        spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
        schedule();
        spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
        remove_wait_queue(&raw->empty_wait, &wait);
        set_current_state(TASK_RUNNING);
        raw->port.flags &= ~(ASYNC_INITIALIZED | ASYNC_CLOSING);
    }
    spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
}

static struct raw3215_info *raw3215_alloc_info(void)
{
    struct raw3215_info *info;

    info = kzalloc(sizeof(struct raw3215_info), GFP_KERNEL | GFP_DMA);
    if (!info)
        return NULL;

    info->buffer = kzalloc(RAW3215_BUFFER_SIZE, GFP_KERNEL | GFP_DMA);
    info->inbuf = kzalloc(RAW3215_INBUF_SIZE, GFP_KERNEL | GFP_DMA);
    if (!info->buffer || !info->inbuf) {
        kfree(info);
        return NULL;
    }

    setup_timer(&info->timer, raw3215_timeout, (unsigned long)info);
    init_waitqueue_head(&info->empty_wait);
    tasklet_init(&info->tlet, raw3215_wakeup, (unsigned long)info);
    tty_port_init(&info->port);

    return info;
}

static void raw3215_free_info(struct raw3215_info *raw)
{
    kfree(raw->inbuf);
    kfree(raw->buffer);
    kfree(raw);
}

static int raw3215_probe (struct ccw_device *cdev)
{
    struct raw3215_info *raw;
    int line;

    /* Console is special. */
    if (raw3215[0] && (raw3215[0] == dev_get_drvdata(&cdev->dev)))
        return 0;

    raw = raw3215_alloc_info();
    if (raw == NULL)
        return -ENOMEM;

    raw->cdev = cdev;
    dev_set_drvdata(&cdev->dev, raw);
    cdev->handler = raw3215_irq;

    spin_lock(&raw3215_device_lock);
    for (line = 0; line < NR_3215; line++) {
        if (!raw3215[line]) {
            raw3215[line] = raw;
            break;
        }
    }
    spin_unlock(&raw3215_device_lock);
    if (line == NR_3215) {
        raw3215_free_info(raw);
        return -ENODEV;
    }

    return 0;
}

static void raw3215_remove (struct ccw_device *cdev)
{
    struct raw3215_info *raw;
    unsigned int line;

    ccw_device_set_offline(cdev);
    raw = dev_get_drvdata(&cdev->dev);
    if (raw) {
        spin_lock(&raw3215_device_lock);
        for (line = 0; line < NR_3215; line++)
            if (raw3215[line] == raw)
                break;
        raw3215[line] = NULL;
        spin_unlock(&raw3215_device_lock);
        dev_set_drvdata(&cdev->dev, NULL);
        raw3215_free_info(raw);
    }
}

static int raw3215_set_online (struct ccw_device *cdev)
{
    struct raw3215_info *raw;

    raw = dev_get_drvdata(&cdev->dev);
    if (!raw)
        return -ENODEV;

    return raw3215_startup(raw);
}

static int raw3215_set_offline (struct ccw_device *cdev)
{
    struct raw3215_info *raw;

    raw = dev_get_drvdata(&cdev->dev);
    if (!raw)
        return -ENODEV;

    raw3215_shutdown(raw);

    return 0;
}

static int raw3215_pm_stop(struct ccw_device *cdev)
{
    struct raw3215_info *raw;
    unsigned long flags;

    /* Empty the output buffer, then prevent new I/O. */
    raw = dev_get_drvdata(&cdev->dev);
    spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
    raw3215_make_room(raw, RAW3215_BUFFER_SIZE);
    raw->port.flags |= ASYNC_SUSPENDED;
    spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
    return 0;
}

static int raw3215_pm_start(struct ccw_device *cdev)
{
    struct raw3215_info *raw;
    unsigned long flags;

    /* Allow I/O again and flush output buffer. */
    raw = dev_get_drvdata(&cdev->dev);
    spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
    raw->port.flags &= ~ASYNC_SUSPENDED;
    raw->flags |= RAW3215_FLUSHING;
    raw3215_try_io(raw);
    raw->flags &= ~RAW3215_FLUSHING;
    spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
    return 0;
}

static struct ccw_device_id raw3215_id[] = {
    { CCW_DEVICE(0x3215, 0) },
    { /* end of list */ },
};

static struct ccw_driver raw3215_ccw_driver = {
    .driver = {
        .name   = "3215",
        .owner  = THIS_MODULE,
    },
    .ids        = raw3215_id,
    .probe      = &raw3215_probe,
    .remove     = &raw3215_remove,
    .set_online = &raw3215_set_online,
    .set_offline    = &raw3215_set_offline,
    .freeze     = &raw3215_pm_stop,
    .thaw       = &raw3215_pm_start,
    .restore    = &raw3215_pm_start,
    .int_class  = IOINT_C15,
};

#ifdef CONFIG_TN3215_CONSOLE
/*
 * Write a string to the 3215 console
 */
static void con3215_write(struct console *co, const char *str,
              unsigned int count)
{
    struct raw3215_info *raw;
    int i;

    if (count <= 0)
        return;
    raw = raw3215[0];   /* console 3215 is the first one */
    while (count > 0) {
        for (i = 0; i < count; i++)
            if (str[i] == '\t' || str[i] == '\n')
                break;
        raw3215_write(raw, str, i);
        count -= i;
        str += i;
        if (count > 0) {
            raw3215_putchar(raw, *str);
            count--;
            str++;
        }
    }
}

static struct tty_driver *con3215_device(struct console *c, int *index)
{
    *index = c->index;
    return tty3215_driver;
}

/*
 * panic() calls con3215_flush through a panic_notifier
 * before the system enters a disabled, endless loop.
 */
static void con3215_flush(void)
{
    struct raw3215_info *raw;
    unsigned long flags;

    raw = raw3215[0];  /* console 3215 is the first one */
    if (raw->port.flags & ASYNC_SUSPENDED)
        /* The console is still frozen for suspend. */
        if (ccw_device_force_console())
            /* Forcing didn't work, no panic message .. */
            return;
    spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
    raw3215_make_room(raw, RAW3215_BUFFER_SIZE);
    spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
}

static int con3215_notify(struct notifier_block *self,
              unsigned long event, void *data)
{
    con3215_flush();
    return NOTIFY_OK;
}

static struct notifier_block on_panic_nb = {
    .notifier_call = con3215_notify,
    .priority = 0,
};

static struct notifier_block on_reboot_nb = {
    .notifier_call = con3215_notify,
    .priority = 0,
};

/*
 *  The console structure for the 3215 console
 */
static struct console con3215 = {
    .name    = "ttyS",
    .write   = con3215_write,
    .device  = con3215_device,
    .flags   = CON_PRINTBUFFER,
};

/*
 * 3215 console initialization code called from console_init().
 */
static int __init con3215_init(void)
{
    struct ccw_device *cdev;
    struct raw3215_info *raw;
    struct raw3215_req *req;
    int i;

    /* Check if 3215 is to be the console */
    if (!CONSOLE_IS_3215)
        return -ENODEV;

    /* Set the console mode for VM */
    if (MACHINE_IS_VM) {
        cpcmd("TERM CONMODE 3215", NULL, 0, NULL);
        cpcmd("TERM AUTOCR OFF", NULL, 0, NULL);
    }

    /* allocate 3215 request structures */
    raw3215_freelist = NULL;
    spin_lock_init(&raw3215_freelist_lock);
    for (i = 0; i < NR_3215_REQ; i++) {
        req = kzalloc(sizeof(struct raw3215_req), GFP_KERNEL | GFP_DMA);
        req->next = raw3215_freelist;
        raw3215_freelist = req;
    }

    cdev = ccw_device_probe_console();
    if (IS_ERR(cdev))
        return -ENODEV;

    raw3215[0] = raw = raw3215_alloc_info();
    raw->cdev = cdev;
    dev_set_drvdata(&cdev->dev, raw);
    cdev->handler = raw3215_irq;

    /* Request the console irq */
    if (raw3215_startup(raw) != 0) {
        raw3215_free_info(raw);
        raw3215[0] = NULL;
        return -ENODEV;
    }
    atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
    register_reboot_notifier(&on_reboot_nb);
    register_console(&con3215);
    return 0;
}
console_initcall(con3215_init);
#endif

static int tty3215_install(struct tty_driver *driver, struct tty_struct *tty)
{
    struct raw3215_info *raw;

    raw = raw3215[tty->index];
    if (raw == NULL)
        return -ENODEV;

    tty->driver_data = raw;

    return tty_port_install(&raw->port, driver, tty);
}

/*
 * tty3215_open
 *
 * This routine is called whenever a 3215 tty is opened.
 */
static int tty3215_open(struct tty_struct *tty, struct file * filp)
{
    struct raw3215_info *raw = tty->driver_data;
    int retval;

    tty_port_tty_set(&raw->port, tty);

    tty->low_latency = 0;  /* don't use bottom half for pushing chars */
    /*
     * Start up 3215 device
     */
    retval = raw3215_startup(raw);
    if (retval)
        return retval;

    return 0;
}

/*
 * tty3215_close()
 *
 * This routine is called when the 3215 tty is closed. We wait
 * for the remaining request to be completed. Then we clean up.
 */
static void tty3215_close(struct tty_struct *tty, struct file * filp)
{
    struct raw3215_info *raw;

    raw = (struct raw3215_info *) tty->driver_data;
    if (raw == NULL || tty->count > 1)
        return;
    tty->closing = 1;
    /* Shutdown the terminal */
    raw3215_shutdown(raw);
    tasklet_kill(&raw->tlet);
    tty->closing = 0;
    tty_port_tty_set(&raw->port, NULL);
}

/*
 * Returns the amount of free space in the output buffer.
 */
static int tty3215_write_room(struct tty_struct *tty)
{
    struct raw3215_info *raw;

    raw = (struct raw3215_info *) tty->driver_data;

    /* Subtract TAB_STOP_SIZE to allow for a tab, 8 <<< 64K */
    if ((RAW3215_BUFFER_SIZE - raw->count - TAB_STOP_SIZE) >= 0)
        return RAW3215_BUFFER_SIZE - raw->count - TAB_STOP_SIZE;
    else
        return 0;
}

/*
 * String write routine for 3215 ttys
 */
static int tty3215_write(struct tty_struct * tty,
             const unsigned char *buf, int count)
{
    struct raw3215_info *raw;

    if (!tty)
        return 0;
    raw = (struct raw3215_info *) tty->driver_data;
    raw3215_write(raw, buf, count);
    return count;
}

/*
 * Put character routine for 3215 ttys
 */
static int tty3215_put_char(struct tty_struct *tty, unsigned char ch)
{
    struct raw3215_info *raw;

    if (!tty)
        return 0;
    raw = (struct raw3215_info *) tty->driver_data;
    raw3215_putchar(raw, ch);
    return 1;
}

static void tty3215_flush_chars(struct tty_struct *tty)
{
}

/*
 * Returns the number of characters in the output buffer
 */
static int tty3215_chars_in_buffer(struct tty_struct *tty)
{
    struct raw3215_info *raw;

    raw = (struct raw3215_info *) tty->driver_data;
    return raw->count;
}

static void tty3215_flush_buffer(struct tty_struct *tty)
{
    struct raw3215_info *raw;

    raw = (struct raw3215_info *) tty->driver_data;
    raw3215_flush_buffer(raw);
    tty_wakeup(tty);
}

/*
 * Disable reading from a 3215 tty
 */
static void tty3215_throttle(struct tty_struct * tty)
{
    struct raw3215_info *raw;

    raw = (struct raw3215_info *) tty->driver_data;
    raw->flags |= RAW3215_THROTTLED;
}

/*
 * Enable reading from a 3215 tty
 */
static void tty3215_unthrottle(struct tty_struct * tty)
{
    struct raw3215_info *raw;
    unsigned long flags;

    raw = (struct raw3215_info *) tty->driver_data;
    if (raw->flags & RAW3215_THROTTLED) {
        spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
        raw->flags &= ~RAW3215_THROTTLED;
        raw3215_try_io(raw);
        spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
    }
}

/*
 * Disable writing to a 3215 tty
 */
static void tty3215_stop(struct tty_struct *tty)
{
    struct raw3215_info *raw;

    raw = (struct raw3215_info *) tty->driver_data;
    raw->flags |= RAW3215_STOPPED;
}

/*
 * Enable writing to a 3215 tty
 */
static void tty3215_start(struct tty_struct *tty)
{
    struct raw3215_info *raw;
    unsigned long flags;

    raw = (struct raw3215_info *) tty->driver_data;
    if (raw->flags & RAW3215_STOPPED) {
        spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
        raw->flags &= ~RAW3215_STOPPED;
        raw3215_try_io(raw);
        spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
    }
}

static const struct tty_operations tty3215_ops = {
    .install = tty3215_install,
    .open = tty3215_open,
    .close = tty3215_close,
    .write = tty3215_write,
    .put_char = tty3215_put_char,
    .flush_chars = tty3215_flush_chars,
    .write_room = tty3215_write_room,
    .chars_in_buffer = tty3215_chars_in_buffer,
    .flush_buffer = tty3215_flush_buffer,
    .throttle = tty3215_throttle,
    .unthrottle = tty3215_unthrottle,
    .stop = tty3215_stop,
    .start = tty3215_start,
};

/*
 * 3215 tty registration code called from tty_init().
 * Most kernel services (incl. kmalloc) are available at this poimt.
 */
static int __init tty3215_init(void)
{
    struct tty_driver *driver;
    int ret;

    if (!CONSOLE_IS_3215)
        return 0;

    driver = alloc_tty_driver(NR_3215);
    if (!driver)
        return -ENOMEM;

    ret = ccw_driver_register(&raw3215_ccw_driver);
    if (ret) {
        put_tty_driver(driver);
        return ret;
    }
    /*
     * Initialize the tty_driver structure
     * Entries in tty3215_driver that are NOT initialized:
     * proc_entry, set_termios, flush_buffer, set_ldisc, write_proc
     */

    driver->driver_name = "tty3215";
    driver->name = "ttyS";
    driver->major = TTY_MAJOR;
    driver->minor_start = 64;
    driver->type = TTY_DRIVER_TYPE_SYSTEM;
    driver->subtype = SYSTEM_TYPE_TTY;
    driver->init_termios = tty_std_termios;
    driver->init_termios.c_iflag = IGNBRK | IGNPAR;
    driver->init_termios.c_oflag = ONLCR | XTABS;
    driver->init_termios.c_lflag = ISIG;
    driver->flags = TTY_DRIVER_REAL_RAW;
    tty_set_operations(driver, &tty3215_ops);
    ret = tty_register_driver(driver);
    if (ret) {
        put_tty_driver(driver);
        return ret;
    }
    tty3215_driver = driver;
    return 0;
}

static void __exit tty3215_exit(void)
{
    tty_unregister_driver(tty3215_driver);
    put_tty_driver(tty3215_driver);
    ccw_driver_unregister(&raw3215_ccw_driver);
}

module_init(tty3215_init);
module_exit(tty3215_exit);