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con3215.c

/*
 *  drivers/s390/char/con3215.c
 *    3215 line mode terminal driver.
 *
 *  S390 version
 *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
 *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
 *
 *  Updated:
 *   Aug-2000: Added tab support
 *           Dan Morrison, IBM Corporation (dmorriso@cse.buffalo.edu)
 */

#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/slab.h>
#include <linux/bootmem.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_FIXED       1       /* 3215 console device is not be freed */
#define RAW3215_ACTIVE      2       /* set if the device is in use */
#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_CLOSING     32            /* set while in close process */
#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 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 tty_struct *tty;       /* pointer to tty structure if present */
      struct tasklet_struct tasklet;
      struct raw3215_req *queued_read; /* pointer to queued read requests */
      struct raw3215_req *queued_write;/* pointer to queued write requests */
      wait_queue_head_t empty_wait; /* wait queue for flushing */
      struct timer_list timer;      /* timer for delayed output */
      char *message;                /* pending message from raw3215_irq */
      int msg_dstat;                /* dstat for pending message */
      int msg_cstat;                /* cstat for pending message */
      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;
            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->flags & RAW3215_ACTIVE))
            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 */
                  init_timer(&raw->timer);
                  raw->timer.expires = RAW3215_TIMEOUT + jiffies;
                  raw->timer.data = (unsigned long) raw;
                  raw->timer.function = raw3215_timeout;
                  add_timer(&raw->timer);
                  raw->flags |= RAW3215_TIMER_RUNS;
            }
      }
}

/*
 * The bottom half handler routine for 3215 devices. It tries to start
 * the next IO and wakes up processes waiting on the tty.
 */
static void
raw3215_tasklet(void *data)
{
      struct raw3215_info *raw;
      struct tty_struct *tty;
      unsigned long flags;

      raw = (struct raw3215_info *) data;
      spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
      raw3215_mk_write_req(raw);
      raw3215_try_io(raw);
      spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
      /* Check for pending message from raw3215_irq */
      if (raw->message != NULL) {
            printk(raw->message, raw->msg_dstat, raw->msg_cstat);
            raw->message = NULL;
      }
      tty = raw->tty;
      if (tty != NULL &&
          RAW3215_BUFFER_SIZE - raw->count >= RAW3215_MIN_SPACE) {
            tty_wakeup(tty);
      }
}

/*
 * 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, slen;

      raw = cdev->dev.driver_data;
      req = (struct raw3215_req *) intparm;
      cstat = irb->scsw.cstat;
      dstat = irb->scsw.dstat;
      if (cstat != 0) {
            raw->message = KERN_WARNING
                  "Got nonzero channel status in raw3215_irq "
                  "(dev sts 0x%2x, sch sts 0x%2x)";
            raw->msg_dstat = dstat;
            raw->msg_cstat = cstat;
            tasklet_schedule(&raw->tasklet);
      }
      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);
            if (MACHINE_IS_P390)
                  memset(raw->inbuf, 0, RAW3215_INBUF_SIZE);
            tasklet_schedule(&raw->tasklet);
            break;
      case 0x08:
      case 0x0C:
            /* Channel end interrupt. */
            if ((raw = req->info) == NULL)
                  return;                /* That shouldn't happen ... */
            if (req->type == RAW3215_READ) {
                  /* store residual count, then wait for device end */
                  req->residual = irb->scsw.count;
            }
            if (dstat == 0x08)
                  break;
      case 0x04:
            /* Device end interrupt. */
            if ((raw = req->info) == NULL)
                  return;                /* That shouldn't happen ... */
            if (req->type == RAW3215_READ && raw->tty != NULL) {
                  unsigned int cchar;

                  tty = raw->tty;
                  count = 160 - req->residual;
                  if (MACHINE_IS_P390) {
                        slen = strnlen(raw->inbuf, RAW3215_INBUF_SIZE);
                        if (count > slen)
                              count = slen;
                  } else
                  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(raw->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(raw->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);
            }
            tasklet_schedule(&raw->tasklet);
            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);
            }
            raw->message = KERN_WARNING
                  "Spurious interrupt in in raw3215_irq "
                  "(dev sts 0x%2x, sch sts 0x%2x)";
            raw->msg_dstat = dstat;
            raw->msg_cstat = cstat;
            tasklet_schedule(&raw->tasklet);
      }
      return;
}

/*
 * 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) {
            /* 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->flags & RAW3215_ACTIVE)
            return 0;
      raw->line_pos = 0;
      raw->flags |= RAW3215_ACTIVE;
      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->flags & RAW3215_ACTIVE) || (raw->flags & RAW3215_FIXED))
            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->flags |= RAW3215_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->flags &= ~(RAW3215_ACTIVE | RAW3215_CLOSING);
      }
      spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
}

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

      /* Console is special. */
      if (raw3215[0] && (cdev->dev.driver_data == raw3215[0]))
            return 0;
      raw = kmalloc(sizeof(struct raw3215_info) +
                  RAW3215_INBUF_SIZE, GFP_KERNEL|GFP_DMA);
      if (raw == NULL)
            return -ENOMEM;

      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) {
            kfree(raw);
            return -ENODEV;
      }

      raw->cdev = cdev;
      raw->inbuf = (char *) raw + sizeof(struct raw3215_info);
      memset(raw, 0, sizeof(struct raw3215_info));
      raw->buffer = kmalloc(RAW3215_BUFFER_SIZE,
                               GFP_KERNEL|GFP_DMA);
      if (raw->buffer == NULL) {
            spin_lock(&raw3215_device_lock);
            raw3215[line] = NULL;
            spin_unlock(&raw3215_device_lock);
            kfree(raw);
            return -ENOMEM;
      }
      tasklet_init(&raw->tasklet,
                 (void (*)(unsigned long)) raw3215_tasklet,
                 (unsigned long) raw);
      init_waitqueue_head(&raw->empty_wait);

      cdev->dev.driver_data = raw;
      cdev->handler = raw3215_irq;

      return 0;
}

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

      ccw_device_set_offline(cdev);
      raw = cdev->dev.driver_data;
      if (raw) {
            cdev->dev.driver_data = NULL;
            kfree(raw->buffer);
            kfree(raw);
      }
}

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

      raw = cdev->dev.driver_data;
      if (!raw)
            return -ENODEV;

      return raw3215_startup(raw);
}

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

      raw = cdev->dev.driver_data;
      if (!raw)
            return -ENODEV;

      raw3215_shutdown(raw);

      return 0;
}

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

static struct ccw_driver raw3215_ccw_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,
};

#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 console_unblank before the system enters a
 * disabled, endless loop.
 */
static void
con3215_unblank(void)
{
      struct raw3215_info *raw;
      unsigned long flags;

      raw = raw3215[0];  /* console 3215 is the first one */
      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);
}

/*
 *  The console structure for the 3215 console
 */
static struct console con3215 = {
      .name  = "ttyS",
      .write       = con3215_write,
      .device      = con3215_device,
      .unblank = con3215_unblank,
      .flags       = CON_PRINTBUFFER,
};

/*
 * 3215 console initialization code called from console_init().
 * NOTE: This is called before kmalloc is available.
 */
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 = (struct raw3215_req *) alloc_bootmem_low(sizeof(struct raw3215_req));
            req->next = raw3215_freelist;
            raw3215_freelist = req;
      }

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

      raw3215[0] = raw = (struct raw3215_info *)
            alloc_bootmem_low(sizeof(struct raw3215_info));
      memset(raw, 0, sizeof(struct raw3215_info));
      raw->buffer = (char *) alloc_bootmem_low(RAW3215_BUFFER_SIZE);
      raw->inbuf = (char *) alloc_bootmem_low(RAW3215_INBUF_SIZE);
      raw->cdev = cdev;
      cdev->dev.driver_data = raw;
      cdev->handler = raw3215_irq;

      raw->flags |= RAW3215_FIXED;
      tasklet_init(&raw->tasklet,
                 (void (*)(unsigned long)) raw3215_tasklet,
                 (unsigned long) raw);
      init_waitqueue_head(&raw->empty_wait);

      /* Request the console irq */
      if (raw3215_startup(raw) != 0) {
            free_bootmem((unsigned long) raw->inbuf, RAW3215_INBUF_SIZE);
            free_bootmem((unsigned long) raw->buffer, RAW3215_BUFFER_SIZE);
            free_bootmem((unsigned long) raw, sizeof(struct raw3215_info));
            raw3215[0] = NULL;
            printk("Couldn't find a 3215 console device\n");
            return -ENODEV;
      }
      register_console(&con3215);
      return 0;
}
console_initcall(con3215_init);
#endif

/*
 * 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;
      int retval, line;

      line = tty->index;
      if ((line < 0) || (line >= NR_3215))
            return -ENODEV;

      raw = raw3215[line];
      if (raw == NULL)
            return -ENODEV;

      tty->driver_data = raw;
      raw->tty = 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);
      tty->closing = 0;
      raw->tty = 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 void
tty3215_put_char(struct tty_struct *tty, unsigned char ch)
{
      struct raw3215_info *raw;

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

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);
}

/*
 * Currently we don't have any io controls for 3215 ttys
 */
static int
tty3215_ioctl(struct tty_struct *tty, struct file * file,
            unsigned int cmd, unsigned long arg)
{
      if (tty->flags & (1 << TTY_IO_ERROR))
            return -EIO;

      switch (cmd) {
      default:
            return -ENOIOCTLCMD;
      }
      return 0;
}

/*
 * 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 = {
      .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,
      .ioctl = tty3215_ioctl,
      .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->owner = THIS_MODULE;
      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) {
            printk("Couldn't register tty3215 driver\n");
            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);

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