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tty3270.c

/*
 *  drivers/s390/char/tty3270.c
 *    IBM/3270 Driver - tty functions.
 *
 *  Author(s):
 *    Original 3270 Code for 2.4 written by Richard Hitt (UTS Global)
 *    Rewritten for 2.5 by Martin Schwidefsky <schwidefsky@de.ibm.com>
 *    -- Copyright (C) 2003 IBM Deutschland Entwicklung GmbH, IBM Corporation
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kdev_t.h>
#include <linux/tty.h>
#include <linux/vt_kern.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/interrupt.h>

#include <linux/slab.h>
#include <linux/bootmem.h>

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

#include "raw3270.h"
#include "tty3270.h"
#include "keyboard.h"

#define TTY3270_CHAR_BUF_SIZE 256
#define TTY3270_OUTPUT_BUFFER_SIZE 1024
#define TTY3270_STRING_PAGES 5

struct tty_driver *tty3270_driver;
static int tty3270_max_index;

static struct raw3270_fn tty3270_fn;

struct tty3270_cell {
      unsigned char character;
      unsigned char highlight;
      unsigned char f_color;
};

struct tty3270_line {
      struct tty3270_cell *cells;
      int len;
};

#define ESCAPE_NPAR 8

/*
 * The main tty view data structure.
 * FIXME:
 * 1) describe line orientation & lines list concept against screen
 * 2) describe conversion of screen to lines
 * 3) describe line format.
 */
struct tty3270 {
      struct raw3270_view view;
      struct tty_struct *tty;       /* Pointer to tty structure */
      void **freemem_pages;         /* Array of pages used for freemem. */
      struct list_head freemem;     /* List of free memory for strings. */

      /* Output stuff. */
      struct list_head lines;       /* List of lines. */
      struct list_head update;      /* List of lines to update. */
      unsigned char wcc;            /* Write control character. */
      int nr_lines;                 /* # lines in list. */
      int nr_up;              /* # lines up in history. */
      unsigned long update_flags;   /* Update indication bits. */
      struct string *status;        /* Lower right of display. */
      struct raw3270_request *write;      /* Single write request. */
      struct timer_list timer;      /* Output delay timer. */

      /* Current tty screen. */
      unsigned int cx, cy;          /* Current output position. */
      unsigned int highlight;       /* Blink/reverse/underscore */
      unsigned int f_color;         /* Foreground color */
      struct tty3270_line *screen;

      /* Input stuff. */
      struct string *prompt;        /* Output string for input area. */
      struct string *input;         /* Input string for read request. */
      struct raw3270_request *read; /* Single read request. */
      struct raw3270_request *kreset;     /* Single keyboard reset request. */
      unsigned char inattr;         /* Visible/invisible input. */
      int throttle, attn;           /* tty throttle/unthrottle. */
      struct tasklet_struct readlet;      /* Tasklet to issue read request. */
      struct kbd_data *kbd;         /* key_maps stuff. */

      /* Escape sequence parsing. */
      int esc_state, esc_ques, esc_npar;
      int esc_par[ESCAPE_NPAR];
      unsigned int saved_cx, saved_cy;
      unsigned int saved_highlight, saved_f_color;

      /* Command recalling. */
      struct list_head rcl_lines;   /* List of recallable lines. */
      struct list_head *rcl_walk;   /* Point in rcl_lines list. */
      int rcl_nr, rcl_max;          /* Number/max number of rcl_lines. */

      /* Character array for put_char/flush_chars. */
      unsigned int char_count;
      char char_buf[TTY3270_CHAR_BUF_SIZE];
};

/* tty3270->update_flags. See tty3270_update for details. */
#define TTY_UPDATE_ERASE      1     /* Use EWRITEA instead of WRITE. */
#define TTY_UPDATE_LIST       2     /* Update lines in tty3270->update. */
#define TTY_UPDATE_INPUT      4     /* Update input line. */
#define TTY_UPDATE_STATUS     8     /* Update status line. */
#define TTY_UPDATE_ALL        15

static void tty3270_update(struct tty3270 *);

/*
 * Setup timeout for a device. On timeout trigger an update.
 */
static void tty3270_set_timer(struct tty3270 *tp, int expires)
{
      if (expires == 0) {
            if (timer_pending(&tp->timer) && del_timer(&tp->timer))
                  raw3270_put_view(&tp->view);
            return;
      }
      if (timer_pending(&tp->timer) &&
          mod_timer(&tp->timer, jiffies + expires))
            return;
      raw3270_get_view(&tp->view);
      tp->timer.function = (void (*)(unsigned long)) tty3270_update;
      tp->timer.data = (unsigned long) tp;
      tp->timer.expires = jiffies + expires;
      add_timer(&tp->timer);
}

/*
 * The input line are the two last lines of the screen.
 */
static void
tty3270_update_prompt(struct tty3270 *tp, char *input, int count)
{
      struct string *line;
      unsigned int off;

      line = tp->prompt;
      if (count != 0)
            line->string[5] = TF_INMDT;
      else
            line->string[5] = tp->inattr;
      if (count > tp->view.cols * 2 - 11)
            count = tp->view.cols * 2 - 11;
      memcpy(line->string + 6, input, count);
      line->string[6 + count] = TO_IC;
      /* Clear to end of input line. */
      if (count < tp->view.cols * 2 - 11) {
            line->string[7 + count] = TO_RA;
            line->string[10 + count] = 0;
            off = tp->view.cols * tp->view.rows - 9;
            raw3270_buffer_address(tp->view.dev, line->string+count+8, off);
            line->len = 11 + count;
      } else
            line->len = 7 + count;
      tp->update_flags |= TTY_UPDATE_INPUT;
}

static void
tty3270_create_prompt(struct tty3270 *tp)
{
      static const unsigned char blueprint[] =
            { TO_SBA, 0, 0, 0x6e, TO_SF, TF_INPUT,
              /* empty input string */
              TO_IC, TO_RA, 0, 0, 0 };
      struct string *line;
      unsigned int offset;

      line = alloc_string(&tp->freemem,
                      sizeof(blueprint) + tp->view.cols * 2 - 9);
      tp->prompt = line;
      tp->inattr = TF_INPUT;
      /* Copy blueprint to status line */
      memcpy(line->string, blueprint, sizeof(blueprint));
      line->len = sizeof(blueprint);
      /* Set output offsets. */
      offset = tp->view.cols * (tp->view.rows - 2);
      raw3270_buffer_address(tp->view.dev, line->string + 1, offset);
      offset = tp->view.cols * tp->view.rows - 9;
      raw3270_buffer_address(tp->view.dev, line->string + 8, offset);

      /* Allocate input string for reading. */
      tp->input = alloc_string(&tp->freemem, tp->view.cols * 2 - 9 + 6);
}

/*
 * The status line is the last line of the screen. It shows the string
 * "Running"/"Holding" in the lower right corner of the screen.
 */
static void
tty3270_update_status(struct tty3270 * tp)
{
      char *str;

      str = (tp->nr_up != 0) ? "History" : "Running";
      memcpy(tp->status->string + 8, str, 7);
      codepage_convert(tp->view.ascebc, tp->status->string + 8, 7);
      tp->update_flags |= TTY_UPDATE_STATUS;
}

static void
tty3270_create_status(struct tty3270 * tp)
{
      static const unsigned char blueprint[] =
            { TO_SBA, 0, 0, TO_SF, TF_LOG, TO_SA, TAT_COLOR, TAC_GREEN,
              0, 0, 0, 0, 0, 0, 0, TO_SF, TF_LOG, TO_SA, TAT_COLOR,
              TAC_RESET };
      struct string *line;
      unsigned int offset;

      line = alloc_string(&tp->freemem,sizeof(blueprint));
      tp->status = line;
      /* Copy blueprint to status line */
      memcpy(line->string, blueprint, sizeof(blueprint));
      /* Set address to start of status string (= last 9 characters). */
      offset = tp->view.cols * tp->view.rows - 9;
      raw3270_buffer_address(tp->view.dev, line->string + 1, offset);
}

/*
 * Set output offsets to 3270 datastream fragment of a tty string.
 * (TO_SBA offset at the start and TO_RA offset at the end of the string)
 */
static void
tty3270_update_string(struct tty3270 *tp, struct string *line, int nr)
{
      unsigned char *cp;

      raw3270_buffer_address(tp->view.dev, line->string + 1,
                         tp->view.cols * nr);
      cp = line->string + line->len - 4;
      if (*cp == TO_RA)
            raw3270_buffer_address(tp->view.dev, cp + 1,
                               tp->view.cols * (nr + 1));
}

/*
 * Rebuild update list to print all lines.
 */
static void
tty3270_rebuild_update(struct tty3270 *tp)
{
      struct string *s, *n;
      int line, nr_up;

      /* 
       * Throw away update list and create a new one,
       * containing all lines that will fit on the screen.
       */
      list_for_each_entry_safe(s, n, &tp->update, update)
            list_del_init(&s->update);
      line = tp->view.rows - 3;
      nr_up = tp->nr_up;
      list_for_each_entry_reverse(s, &tp->lines, list) {
            if (nr_up > 0) {
                  nr_up--;
                  continue;
            }
            tty3270_update_string(tp, s, line);
            list_add(&s->update, &tp->update);
            if (--line < 0)
                  break;
      }
      tp->update_flags |= TTY_UPDATE_LIST;
}

/*
 * Alloc string for size bytes. If there is not enough room in
 * freemem, free strings until there is room.
 */
static struct string *
tty3270_alloc_string(struct tty3270 *tp, size_t size)
{
      struct string *s, *n;

      s = alloc_string(&tp->freemem, size);
      if (s)
            return s;
      list_for_each_entry_safe(s, n, &tp->lines, list) {
            BUG_ON(tp->nr_lines <= tp->view.rows - 2);
            list_del(&s->list);
            if (!list_empty(&s->update))
                  list_del(&s->update);
            tp->nr_lines--;
            if (free_string(&tp->freemem, s) >= size)
                  break;
      }
      s = alloc_string(&tp->freemem, size);
      BUG_ON(!s);
      if (tp->nr_up != 0 &&
          tp->nr_up + tp->view.rows - 2 >= tp->nr_lines) {
            tp->nr_up = tp->nr_lines - tp->view.rows + 2;
            tty3270_rebuild_update(tp);
            tty3270_update_status(tp);
      }
      return s;
}

/*
 * Add an empty line to the list.
 */
static void
tty3270_blank_line(struct tty3270 *tp)
{
      static const unsigned char blueprint[] =
            { TO_SBA, 0, 0, TO_SA, TAT_EXTHI, TAX_RESET,
              TO_SA, TAT_COLOR, TAC_RESET, TO_RA, 0, 0, 0 };
      struct string *s;

      s = tty3270_alloc_string(tp, sizeof(blueprint));
      memcpy(s->string, blueprint, sizeof(blueprint));
      s->len = sizeof(blueprint);
      list_add_tail(&s->list, &tp->lines);
      tp->nr_lines++;
      if (tp->nr_up != 0)
            tp->nr_up++;
}

/*
 * Write request completion callback.
 */
static void
tty3270_write_callback(struct raw3270_request *rq, void *data)
{
      struct tty3270 *tp;

      tp = (struct tty3270 *) rq->view;
      if (rq->rc != 0) {
            /* Write wasn't successfull. Refresh all. */
            tty3270_rebuild_update(tp);
            tp->update_flags = TTY_UPDATE_ALL;
            tty3270_set_timer(tp, 1);
      }
      raw3270_request_reset(rq);
      xchg(&tp->write, rq);
}

/*
 * Update 3270 display.
 */
static void
tty3270_update(struct tty3270 *tp)
{
      static char invalid_sba[2] = { 0xff, 0xff };
      struct raw3270_request *wrq;
      unsigned long updated;
      struct string *s, *n;
      char *sba, *str;
      int rc, len;

      wrq = xchg(&tp->write, 0);
      if (!wrq) {
            tty3270_set_timer(tp, 1);
            return;
      }

      spin_lock(&tp->view.lock);
      updated = 0;
      if (tp->update_flags & TTY_UPDATE_ERASE) {
            /* Use erase write alternate to erase display. */
            raw3270_request_set_cmd(wrq, TC_EWRITEA);
            updated |= TTY_UPDATE_ERASE;
      } else
            raw3270_request_set_cmd(wrq, TC_WRITE);

      raw3270_request_add_data(wrq, &tp->wcc, 1);
      tp->wcc = TW_NONE;

      /*
       * Update status line.
       */
      if (tp->update_flags & TTY_UPDATE_STATUS)
            if (raw3270_request_add_data(wrq, tp->status->string,
                                   tp->status->len) == 0)
                  updated |= TTY_UPDATE_STATUS;

      /*
       * Write input line.
       */
      if (tp->update_flags & TTY_UPDATE_INPUT)
            if (raw3270_request_add_data(wrq, tp->prompt->string,
                                   tp->prompt->len) == 0)
                  updated |= TTY_UPDATE_INPUT;

      sba = invalid_sba;
      
      if (tp->update_flags & TTY_UPDATE_LIST) {
            /* Write strings in the update list to the screen. */
            list_for_each_entry_safe(s, n, &tp->update, update) {
                  str = s->string;
                  len = s->len;
                  /*
                   * Skip TO_SBA at the start of the string if the
                   * last output position matches the start address
                   * of this line.
                   */
                  if (s->string[1] == sba[0] && s->string[2] == sba[1])
                        str += 3, len -= 3;
                  if (raw3270_request_add_data(wrq, str, len) != 0)
                        break;
                  list_del_init(&s->update);
                  sba = s->string + s->len - 3;
            }
            if (list_empty(&tp->update))
                  updated |= TTY_UPDATE_LIST;
      }
      wrq->callback = tty3270_write_callback;
      rc = raw3270_start(&tp->view, wrq);
      if (rc == 0) {
            tp->update_flags &= ~updated;
            if (tp->update_flags)
                  tty3270_set_timer(tp, 1);
      } else {
            raw3270_request_reset(wrq);
            xchg(&tp->write, wrq);
      }
      spin_unlock(&tp->view.lock);
      raw3270_put_view(&tp->view);
}

/*
 * Command recalling.
 */
static void
tty3270_rcl_add(struct tty3270 *tp, char *input, int len)
{
      struct string *s;

      tp->rcl_walk = NULL;
      if (len <= 0)
            return;
      if (tp->rcl_nr >= tp->rcl_max) {
            s = list_entry(tp->rcl_lines.next, struct string, list);
            list_del(&s->list);
            free_string(&tp->freemem, s);
            tp->rcl_nr--;
      }
      s = tty3270_alloc_string(tp, len);
      memcpy(s->string, input, len);
      list_add_tail(&s->list, &tp->rcl_lines);
      tp->rcl_nr++;
}

static void
tty3270_rcl_backward(struct kbd_data *kbd)
{
      struct tty3270 *tp;
      struct string *s;

      tp = kbd->tty->driver_data;
      spin_lock_bh(&tp->view.lock);
      if (tp->inattr == TF_INPUT) {
            if (tp->rcl_walk && tp->rcl_walk->prev != &tp->rcl_lines)
                  tp->rcl_walk = tp->rcl_walk->prev;
            else if (!list_empty(&tp->rcl_lines))
                  tp->rcl_walk = tp->rcl_lines.prev;
            s = tp->rcl_walk ? 
                  list_entry(tp->rcl_walk, struct string, list) : NULL;
            if (tp->rcl_walk) {
                  s = list_entry(tp->rcl_walk, struct string, list);
                  tty3270_update_prompt(tp, s->string, s->len);
            } else
                  tty3270_update_prompt(tp, NULL, 0);
            tty3270_set_timer(tp, 1);
      }
      spin_unlock_bh(&tp->view.lock);
}

/*
 * Deactivate tty view.
 */
static void
tty3270_exit_tty(struct kbd_data *kbd)
{
      struct tty3270 *tp;

      tp = kbd->tty->driver_data;
      raw3270_deactivate_view(&tp->view);
}

/*
 * Scroll forward in history.
 */
static void
tty3270_scroll_forward(struct kbd_data *kbd)
{
      struct tty3270 *tp;
      int nr_up;

      tp = kbd->tty->driver_data;
      spin_lock_bh(&tp->view.lock);
      nr_up = tp->nr_up - tp->view.rows + 2;
      if (nr_up < 0)
            nr_up = 0;
      if (nr_up != tp->nr_up) {
            tp->nr_up = nr_up;
            tty3270_rebuild_update(tp);
            tty3270_update_status(tp);
            tty3270_set_timer(tp, 1);
      }
      spin_unlock_bh(&tp->view.lock);
}

/*
 * Scroll backward in history.
 */
static void
tty3270_scroll_backward(struct kbd_data *kbd)
{
      struct tty3270 *tp;
      int nr_up;

      tp = kbd->tty->driver_data;
      spin_lock_bh(&tp->view.lock);
      nr_up = tp->nr_up + tp->view.rows - 2;
      if (nr_up + tp->view.rows - 2 > tp->nr_lines)
            nr_up = tp->nr_lines - tp->view.rows + 2;
      if (nr_up != tp->nr_up) {
            tp->nr_up = nr_up;
            tty3270_rebuild_update(tp);
            tty3270_update_status(tp);
            tty3270_set_timer(tp, 1);
      }
      spin_unlock_bh(&tp->view.lock);
}

/*
 * Pass input line to tty.
 */
static void
tty3270_read_tasklet(struct raw3270_request *rrq)
{
      static char kreset_data = TW_KR;
      struct tty3270 *tp;
      char *input;
      int len;

      tp = (struct tty3270 *) rrq->view;
      spin_lock_bh(&tp->view.lock);
      /*
       * Two AID keys are special: For 0x7d (enter) the input line
       * has to be emitted to the tty and for 0x6d the screen
       * needs to be redrawn.
       */
      input = NULL;
      len = 0;
      if (tp->input->string[0] == 0x7d) {
            /* Enter: write input to tty. */
            input = tp->input->string + 6;
            len = tp->input->len - 6 - rrq->rescnt;
            if (tp->inattr != TF_INPUTN)
                  tty3270_rcl_add(tp, input, len);
            if (tp->nr_up > 0) {
                  tp->nr_up = 0;
                  tty3270_rebuild_update(tp);
                  tty3270_update_status(tp);
            }
            /* Clear input area. */
            tty3270_update_prompt(tp, NULL, 0);
            tty3270_set_timer(tp, 1);
      } else if (tp->input->string[0] == 0x6d) {
            /* Display has been cleared. Redraw. */
            tty3270_rebuild_update(tp);
            tp->update_flags = TTY_UPDATE_ALL;
            tty3270_set_timer(tp, 1);
      }
      spin_unlock_bh(&tp->view.lock);

      /* Start keyboard reset command. */
      raw3270_request_reset(tp->kreset);
      raw3270_request_set_cmd(tp->kreset, TC_WRITE);
      raw3270_request_add_data(tp->kreset, &kreset_data, 1);
      raw3270_start(&tp->view, tp->kreset);

      /* Emit input string. */
      if (tp->tty) {
            while (len-- > 0)
                  kbd_keycode(tp->kbd, *input++);
            /* Emit keycode for AID byte. */
            kbd_keycode(tp->kbd, 256 + tp->input->string[0]);
      }

      raw3270_request_reset(rrq);
      xchg(&tp->read, rrq);
      raw3270_put_view(&tp->view);
}

/*
 * Read request completion callback.
 */
static void
tty3270_read_callback(struct raw3270_request *rq, void *data)
{
      raw3270_get_view(rq->view);
      /* Schedule tasklet to pass input to tty. */
      tasklet_schedule(&((struct tty3270 *) rq->view)->readlet);
}

/*
 * Issue a read request. Call with device lock.
 */
static void
tty3270_issue_read(struct tty3270 *tp, int lock)
{
      struct raw3270_request *rrq;
      int rc;

      rrq = xchg(&tp->read, 0);
      if (!rrq)
            /* Read already scheduled. */
            return;
      rrq->callback = tty3270_read_callback;
      rrq->callback_data = tp;
      raw3270_request_set_cmd(rrq, TC_READMOD);
      raw3270_request_set_data(rrq, tp->input->string, tp->input->len);
      /* Issue the read modified request. */
      if (lock) {
            rc = raw3270_start(&tp->view, rrq);
      } else
            rc = raw3270_start_irq(&tp->view, rrq);
      if (rc) {
            raw3270_request_reset(rrq);
            xchg(&tp->read, rrq);
      }
}

/*
 * Switch to the tty view.
 */
static int
tty3270_activate(struct raw3270_view *view)
{
      struct tty3270 *tp;
      unsigned long flags;

      tp = (struct tty3270 *) view;
      spin_lock_irqsave(&tp->view.lock, flags);
      tp->nr_up = 0;
      tty3270_rebuild_update(tp);
      tty3270_update_status(tp);
      tp->update_flags = TTY_UPDATE_ALL;
      tty3270_set_timer(tp, 1);
      spin_unlock_irqrestore(&tp->view.lock, flags);
      return 0;
}

static void
tty3270_deactivate(struct raw3270_view *view)
{
}

static int
tty3270_irq(struct tty3270 *tp, struct raw3270_request *rq, struct irb *irb)
{
      /* Handle ATTN. Schedule tasklet to read aid. */
      if (irb->scsw.dstat & DEV_STAT_ATTENTION) {
            if (!tp->throttle)
                  tty3270_issue_read(tp, 0);
            else
                  tp->attn = 1;
      }

      if (rq) {
            if (irb->scsw.dstat & DEV_STAT_UNIT_CHECK)
                  rq->rc = -EIO;
            else
                  /* Normal end. Copy residual count. */
                  rq->rescnt = irb->scsw.count;
      }
      return RAW3270_IO_DONE;
}

/*
 * Allocate tty3270 structure.
 */
static struct tty3270 *
tty3270_alloc_view(void)
{
      struct tty3270 *tp;
      int pages;

      tp = kzalloc(sizeof(struct tty3270), GFP_KERNEL);
      if (!tp)
            goto out_err;
      tp->freemem_pages =
            kmalloc(sizeof(void *) * TTY3270_STRING_PAGES, GFP_KERNEL);
      if (!tp->freemem_pages)
            goto out_tp;
      INIT_LIST_HEAD(&tp->freemem);
      for (pages = 0; pages < TTY3270_STRING_PAGES; pages++) {
            tp->freemem_pages[pages] = (void *)
                  __get_free_pages(GFP_KERNEL|GFP_DMA, 0);
            if (!tp->freemem_pages[pages])
                  goto out_pages;
            add_string_memory(&tp->freemem,
                          tp->freemem_pages[pages], PAGE_SIZE);
      }
      tp->write = raw3270_request_alloc(TTY3270_OUTPUT_BUFFER_SIZE);
      if (IS_ERR(tp->write))
            goto out_pages;
      tp->read = raw3270_request_alloc(0);
      if (IS_ERR(tp->read))
            goto out_write;
      tp->kreset = raw3270_request_alloc(1);
      if (IS_ERR(tp->kreset))
            goto out_read;
      tp->kbd = kbd_alloc();
      if (!tp->kbd)
            goto out_reset;
      return tp;

out_reset:
      raw3270_request_free(tp->kreset);
out_read:
      raw3270_request_free(tp->read);
out_write:
      raw3270_request_free(tp->write);
out_pages:
      while (pages--)
            free_pages((unsigned long) tp->freemem_pages[pages], 0);
      kfree(tp->freemem_pages);
out_tp:
      kfree(tp);
out_err:
      return ERR_PTR(-ENOMEM);
}

/*
 * Free tty3270 structure.
 */
static void
tty3270_free_view(struct tty3270 *tp)
{
      int pages;

      kbd_free(tp->kbd);
      raw3270_request_free(tp->kreset);
      raw3270_request_free(tp->read);
      raw3270_request_free(tp->write);
      for (pages = 0; pages < TTY3270_STRING_PAGES; pages++)
            free_pages((unsigned long) tp->freemem_pages[pages], 0);
      kfree(tp->freemem_pages);
      kfree(tp);
}

/*
 * Allocate tty3270 screen.
 */
static int
tty3270_alloc_screen(struct tty3270 *tp)
{
      unsigned long size;
      int lines;

      size = sizeof(struct tty3270_line) * (tp->view.rows - 2);
      tp->screen = kzalloc(size, GFP_KERNEL);
      if (!tp->screen)
            goto out_err;
      for (lines = 0; lines < tp->view.rows - 2; lines++) {
            size = sizeof(struct tty3270_cell) * tp->view.cols;
            tp->screen[lines].cells = kzalloc(size, GFP_KERNEL);
            if (!tp->screen[lines].cells)
                  goto out_screen;
      }
      return 0;
out_screen:
      while (lines--)
            kfree(tp->screen[lines].cells);
      kfree(tp->screen);
out_err:
      return -ENOMEM;
}

/*
 * Free tty3270 screen.
 */
static void
tty3270_free_screen(struct tty3270 *tp)
{
      int lines;

      for (lines = 0; lines < tp->view.rows - 2; lines++)
            kfree(tp->screen[lines].cells);
      kfree(tp->screen);
}

/*
 * Unlink tty3270 data structure from tty.
 */
static void
tty3270_release(struct raw3270_view *view)
{
      struct tty3270 *tp;
      struct tty_struct *tty;

      tp = (struct tty3270 *) view;
      tty = tp->tty;
      if (tty) {
            tty->driver_data = NULL;
            tp->tty = tp->kbd->tty = NULL;
            tty_hangup(tty);
            raw3270_put_view(&tp->view);
      }
}

/*
 * Free tty3270 data structure
 */
static void
tty3270_free(struct raw3270_view *view)
{
      tty3270_free_screen((struct tty3270 *) view);
      tty3270_free_view((struct tty3270 *) view);
}

/*
 * Delayed freeing of tty3270 views.
 */
static void
tty3270_del_views(void)
{
      struct tty3270 *tp;
      int i;

      for (i = 0; i < tty3270_max_index; i++) {
            tp = (struct tty3270 *)
                  raw3270_find_view(&tty3270_fn, i + RAW3270_FIRSTMINOR);
            if (!IS_ERR(tp))
                  raw3270_del_view(&tp->view);
      }
}

static struct raw3270_fn tty3270_fn = {
      .activate = tty3270_activate,
      .deactivate = tty3270_deactivate,
      .intv = (void *) tty3270_irq,
      .release = tty3270_release,
      .free = tty3270_free
};

/*
 * This routine is called whenever a 3270 tty is opened.
 */
static int
tty3270_open(struct tty_struct *tty, struct file * filp)
{
      struct tty3270 *tp;
      int i, rc;

      if (tty->count > 1)
            return 0;
      /* Check if the tty3270 is already there. */
      tp = (struct tty3270 *)
            raw3270_find_view(&tty3270_fn,
                          tty->index + RAW3270_FIRSTMINOR);
      if (!IS_ERR(tp)) {
            tty->driver_data = tp;
            tty->winsize.ws_row = tp->view.rows - 2;
            tty->winsize.ws_col = tp->view.cols;
            tty->low_latency = 0;
            tp->tty = tty;
            tp->kbd->tty = tty;
            tp->inattr = TF_INPUT;
            return 0;
      }
      if (tty3270_max_index < tty->index + 1)
            tty3270_max_index = tty->index + 1;

      /* Quick exit if there is no device for tty->index. */
      if (PTR_ERR(tp) == -ENODEV)
            return -ENODEV;

      /* Allocate tty3270 structure on first open. */
      tp = tty3270_alloc_view();
      if (IS_ERR(tp))
            return PTR_ERR(tp);

      INIT_LIST_HEAD(&tp->lines);
      INIT_LIST_HEAD(&tp->update);
      INIT_LIST_HEAD(&tp->rcl_lines);
      tp->rcl_max = 20;
      init_timer(&tp->timer);
      tasklet_init(&tp->readlet, 
                 (void (*)(unsigned long)) tty3270_read_tasklet,
                 (unsigned long) tp->read);

      rc = raw3270_add_view(&tp->view, &tty3270_fn,
                        tty->index + RAW3270_FIRSTMINOR);
      if (rc) {
            tty3270_free_view(tp);
            return rc;
      }

      rc = tty3270_alloc_screen(tp);
      if (rc) {
            raw3270_put_view(&tp->view);
            raw3270_del_view(&tp->view);
            return rc;
      }

      tp->tty = tty;
      tty->low_latency = 0;
      tty->driver_data = tp;
      tty->winsize.ws_row = tp->view.rows - 2;
      tty->winsize.ws_col = tp->view.cols;

      tty3270_create_prompt(tp);
      tty3270_create_status(tp);
      tty3270_update_status(tp);

      /* Create blank line for every line in the tty output area. */
      for (i = 0; i < tp->view.rows - 2; i++)
            tty3270_blank_line(tp);

      tp->kbd->tty = tty;
      tp->kbd->fn_handler[KVAL(K_INCRCONSOLE)] = tty3270_exit_tty;
      tp->kbd->fn_handler[KVAL(K_SCROLLBACK)] = tty3270_scroll_backward;
      tp->kbd->fn_handler[KVAL(K_SCROLLFORW)] = tty3270_scroll_forward;
      tp->kbd->fn_handler[KVAL(K_CONS)] = tty3270_rcl_backward;
      kbd_ascebc(tp->kbd, tp->view.ascebc);

      raw3270_activate_view(&tp->view);
      return 0;
}

/*
 * This routine is called when the 3270 tty is closed. We wait
 * for the remaining request to be completed. Then we clean up.
 */
static void
tty3270_close(struct tty_struct *tty, struct file * filp)
{
      struct tty3270 *tp;

      if (tty->count > 1)
            return;
      tp = (struct tty3270 *) tty->driver_data;
      if (tp) {
            tty->driver_data = NULL;
            tp->tty = tp->kbd->tty = NULL;
            raw3270_put_view(&tp->view);
      }
}

/*
 * We always have room.
 */
static int
tty3270_write_room(struct tty_struct *tty)
{
      return INT_MAX;
}

/*
 * Insert character into the screen at the current position with the
 * current color and highlight. This function does NOT do cursor movement.
 */
static void
tty3270_put_character(struct tty3270 *tp, char ch)
{
      struct tty3270_line *line;
      struct tty3270_cell *cell;

      line = tp->screen + tp->cy;
      if (line->len <= tp->cx) {
            while (line->len < tp->cx) {
                  cell = line->cells + line->len;
                  cell->character = tp->view.ascebc[' '];
                  cell->highlight = tp->highlight;
                  cell->f_color = tp->f_color;
                  line->len++;
            }
            line->len++;
      }
      cell = line->cells + tp->cx;
      cell->character = tp->view.ascebc[(unsigned int) ch];
      cell->highlight = tp->highlight;
      cell->f_color = tp->f_color;
}

/*
 * Convert a tty3270_line to a 3270 data fragment usable for output.
 */
static void
tty3270_convert_line(struct tty3270 *tp, int line_nr)
{
      struct tty3270_line *line;
      struct tty3270_cell *cell;
      struct string *s, *n;
      unsigned char highlight;
      unsigned char f_color;
      char *cp;
      int flen, i;

      /* Determine how long the fragment will be. */
      flen = 3;         /* Prefix (TO_SBA). */
      line = tp->screen + line_nr;
      flen += line->len;
      highlight = TAX_RESET;
      f_color = TAC_RESET;
      for (i = 0, cell = line->cells; i < line->len; i++, cell++) {
            if (cell->highlight != highlight) {
                  flen += 3;  /* TO_SA to switch highlight. */
                  highlight = cell->highlight;
            }
            if (cell->f_color != f_color) {
                  flen += 3;  /* TO_SA to switch color. */
                  f_color = cell->f_color;
            }
      }
      if (highlight != TAX_RESET)
            flen += 3;  /* TO_SA to reset hightlight. */
      if (f_color != TAC_RESET)
            flen += 3;  /* TO_SA to reset color. */
      if (line->len < tp->view.cols)
            flen += 4;  /* Postfix (TO_RA). */

      /* Find the line in the list. */
      i = tp->view.rows - 2 - line_nr;
      list_for_each_entry_reverse(s, &tp->lines, list)
            if (--i <= 0)
                  break;
      /*
       * Check if the line needs to get reallocated.
       */
      if (s->len != flen) {
            /* Reallocate string. */
            n = tty3270_alloc_string(tp, flen);
            list_add(&n->list, &s->list);
            list_del_init(&s->list);
            if (!list_empty(&s->update))
                  list_del_init(&s->update);
            free_string(&tp->freemem, s);
            s = n;
      }

      /* Write 3270 data fragment. */
      cp = s->string;
      *cp++ = TO_SBA;
      *cp++ = 0;
      *cp++ = 0;

      highlight = TAX_RESET;
      f_color = TAC_RESET;
      for (i = 0, cell = line->cells; i < line->len; i++, cell++) {
            if (cell->highlight != highlight) {
                  *cp++ = TO_SA;
                  *cp++ = TAT_EXTHI;
                  *cp++ = cell->highlight;
                  highlight = cell->highlight;
            }
            if (cell->f_color != f_color) {
                  *cp++ = TO_SA;
                  *cp++ = TAT_COLOR;
                  *cp++ = cell->f_color;
                  f_color = cell->f_color;
            }
            *cp++ = cell->character;
      }
      if (highlight != TAX_RESET) {
            *cp++ = TO_SA;
            *cp++ = TAT_EXTHI;
            *cp++ = TAX_RESET;
      }
      if (f_color != TAC_RESET) {
            *cp++ = TO_SA;
            *cp++ = TAT_COLOR;
            *cp++ = TAC_RESET;
      }
      if (line->len < tp->view.cols) {
            *cp++ = TO_RA;
            *cp++ = 0;
            *cp++ = 0;
            *cp++ = 0;
      }

      if (tp->nr_up + line_nr < tp->view.rows - 2) {
            /* Line is currently visible on screen. */
            tty3270_update_string(tp, s, line_nr);
            /* Add line to update list. */
            if (list_empty(&s->update)) {
                  list_add_tail(&s->update, &tp->update);
                  tp->update_flags |= TTY_UPDATE_LIST;
            }
      }
}

/*
 * Do carriage return.
 */
static void
tty3270_cr(struct tty3270 *tp)
{
      tp->cx = 0;
}

/*
 * Do line feed.
 */
static void
tty3270_lf(struct tty3270 *tp)
{
      struct tty3270_line temp;
      int i;

      tty3270_convert_line(tp, tp->cy);
      if (tp->cy < tp->view.rows - 3) {
            tp->cy++;
            return;
      }
      /* Last line just filled up. Add new, blank line. */
      tty3270_blank_line(tp);
      temp = tp->screen[0];
      temp.len = 0;
      for (i = 0; i < tp->view.rows - 3; i++)
            tp->screen[i] = tp->screen[i+1];
      tp->screen[tp->view.rows - 3] = temp;
      tty3270_rebuild_update(tp);
}

static void
tty3270_ri(struct tty3270 *tp)
{
      if (tp->cy > 0) {
          tty3270_convert_line(tp, tp->cy);
          tp->cy--;
      }
}

/*
 * Insert characters at current position.
 */
static void
tty3270_insert_characters(struct tty3270 *tp, int n)
{
      struct tty3270_line *line;
      int k;

      line = tp->screen + tp->cy;
      while (line->len < tp->cx) {
            line->cells[line->len].character = tp->view.ascebc[' '];
            line->cells[line->len].highlight = TAX_RESET;
            line->cells[line->len].f_color = TAC_RESET;
            line->len++;
      }
      if (n > tp->view.cols - tp->cx)
            n = tp->view.cols - tp->cx;
      k = min_t(int, line->len - tp->cx, tp->view.cols - tp->cx - n);
      while (k--)
            line->cells[tp->cx + n + k] = line->cells[tp->cx + k];
      line->len += n;
      if (line->len > tp->view.cols)
            line->len = tp->view.cols;
      while (n-- > 0) {
            line->cells[tp->cx + n].character = tp->view.ascebc[' '];
            line->cells[tp->cx + n].highlight = tp->highlight;
            line->cells[tp->cx + n].f_color = tp->f_color;
      }
}

/*
 * Delete characters at current position.
 */
static void
tty3270_delete_characters(struct tty3270 *tp, int n)
{
      struct tty3270_line *line;
      int i;

      line = tp->screen + tp->cy;
      if (line->len <= tp->cx)
            return;
      if (line->len - tp->cx <= n) {
            line->len = tp->cx;
            return;
      }
      for (i = tp->cx; i + n < line->len; i++)
            line->cells[i] = line->cells[i + n];
      line->len -= n;
}

/*
 * Erase characters at current position.
 */
static void
tty3270_erase_characters(struct tty3270 *tp, int n)
{
      struct tty3270_line *line;
      struct tty3270_cell *cell;

      line = tp->screen + tp->cy;
      while (line->len > tp->cx && n-- > 0) {
            cell = line->cells + tp->cx++;
            cell->character = ' ';
            cell->highlight = TAX_RESET;
            cell->f_color = TAC_RESET;
      }
      tp->cx += n;
      tp->cx = min_t(int, tp->cx, tp->view.cols - 1);
}

/*
 * Erase line, 3 different cases:
 *  Esc [ 0 K     Erase from current position to end of line inclusive
 *  Esc [ 1 K     Erase from beginning of line to current position inclusive
 *  Esc [ 2 K     Erase entire line (without moving cursor)
 */
static void
tty3270_erase_line(struct tty3270 *tp, int mode)
{
      struct tty3270_line *line;
      struct tty3270_cell *cell;
      int i;

      line = tp->screen + tp->cy;
      if (mode == 0)
            line->len = tp->cx;
      else if (mode == 1) {
            for (i = 0; i < tp->cx; i++) {
                  cell = line->cells + i;
                  cell->character = ' ';
                  cell->highlight = TAX_RESET;
                  cell->f_color = TAC_RESET;
            }
            if (line->len <= tp->cx)
                  line->len = tp->cx + 1;
      } else if (mode == 2)
            line->len = 0;
      tty3270_convert_line(tp, tp->cy);
}

/*
 * Erase display, 3 different cases:
 *  Esc [ 0 J     Erase from current position to bottom of screen inclusive
 *  Esc [ 1 J     Erase from top of screen to current position inclusive
 *  Esc [ 2 J     Erase entire screen (without moving the cursor)
 */
static void
tty3270_erase_display(struct tty3270 *tp, int mode)
{
      int i;

      if (mode == 0) {
            tty3270_erase_line(tp, 0);
            for (i = tp->cy + 1; i < tp->view.rows - 2; i++) {
                  tp->screen[i].len = 0;
                  tty3270_convert_line(tp, i);
            }
      } else if (mode == 1) {
            for (i = 0; i < tp->cy; i++) {
                  tp->screen[i].len = 0;
                  tty3270_convert_line(tp, i);
            }
            tty3270_erase_line(tp, 1);
      } else if (mode == 2) {
            for (i = 0; i < tp->view.rows - 2; i++) {
                  tp->screen[i].len = 0;
                  tty3270_convert_line(tp, i);
            }
      }
      tty3270_rebuild_update(tp);
}

/*
 * Set attributes found in an escape sequence.
 *  Esc [ <attr> ; <attr> ; ... m
 */
static void
tty3270_set_attributes(struct tty3270 *tp)
{
      static unsigned char f_colors[] = {
            TAC_DEFAULT, TAC_RED, TAC_GREEN, TAC_YELLOW, TAC_BLUE,
            TAC_PINK, TAC_TURQ, TAC_WHITE, 0, TAC_DEFAULT
      };
      int i, attr;

      for (i = 0; i <= tp->esc_npar; i++) {
            attr = tp->esc_par[i];
            switch (attr) {
            case 0:           /* Reset */
                  tp->highlight = TAX_RESET;
                  tp->f_color = TAC_RESET;
                  break;
            /* Highlight. */
            case 4:           /* Start underlining. */
                  tp->highlight = TAX_UNDER;
                  break;
            case 5:           /* Start blink. */
                  tp->highlight = TAX_BLINK;
                  break;
            case 7:           /* Start reverse. */
                  tp->highlight = TAX_REVER;
                  break;
            case 24:    /* End underlining */
                  if (tp->highlight == TAX_UNDER)
                        tp->highlight = TAX_RESET;
                  break;
            case 25:    /* End blink. */
                  if (tp->highlight == TAX_BLINK)
                        tp->highlight = TAX_RESET;
                  break;
            case 27:    /* End reverse. */
                  if (tp->highlight == TAX_REVER)
                        tp->highlight = TAX_RESET;
                  break;
            /* Foreground color. */
            case 30:    /* Black */
            case 31:    /* Red */
            case 32:    /* Green */
            case 33:    /* Yellow */
            case 34:    /* Blue */
            case 35:    /* Magenta */
            case 36:    /* Cyan */
            case 37:    /* White */
            case 39:    /* Black */
                  tp->f_color = f_colors[attr - 30];
                  break;
            }
      }
}

static inline int
tty3270_getpar(struct tty3270 *tp, int ix)
{
      return (tp->esc_par[ix] > 0) ? tp->esc_par[ix] : 1;
}

static void
tty3270_goto_xy(struct tty3270 *tp, int cx, int cy)
{
      int max_cx = max(0, cx);
      int max_cy = max(0, cy);

      tp->cx = min_t(int, tp->view.cols - 1, max_cx);
      cy = min_t(int, tp->view.rows - 3, max_cy);
      if (cy != tp->cy) {
            tty3270_convert_line(tp, tp->cy);
            tp->cy = cy;
      }
}

/*
 * Process escape sequences. Known sequences:
 *  Esc 7               Save Cursor Position
 *  Esc 8               Restore Cursor Position
 *  Esc [ Pn ; Pn ; .. m      Set attributes
 *  Esc [ Pn ; Pn H           Cursor Position
 *  Esc [ Pn ; Pn f           Cursor Position
 *  Esc [ Pn A                Cursor Up
 *  Esc [ Pn B                Cursor Down
 *  Esc [ Pn C                Cursor Forward
 *  Esc [ Pn D                Cursor Backward
 *  Esc [ Pn G                Cursor Horizontal Absolute
 *  Esc [ Pn X                Erase Characters
 *  Esc [ Ps J                Erase in Display
 *  Esc [ Ps K                Erase in Line
 * // FIXME: add all the new ones.
 *
 *  Pn is a numeric parameter, a string of zero or more decimal digits.
 *  Ps is a selective parameter.
 */
static void
tty3270_escape_sequence(struct tty3270 *tp, char ch)
{
      enum { ESnormal, ESesc, ESsquare, ESgetpars };

      if (tp->esc_state == ESnormal) {
            if (ch == 0x1b)
                  /* Starting new escape sequence. */
                  tp->esc_state = ESesc;
            return;
      }
      if (tp->esc_state == ESesc) {
            tp->esc_state = ESnormal;
            switch (ch) {
            case '[':
                  tp->esc_state = ESsquare;
                  break;
            case 'E':
                  tty3270_cr(tp);
                  tty3270_lf(tp);
                  break;
            case 'M':
                  tty3270_ri(tp);
                  break;
            case 'D':
                  tty3270_lf(tp);
                  break;
            case 'Z':         /* Respond ID. */
                  kbd_puts_queue(tp->tty, "\033[?6c");
                  break;
            case '7':         /* Save cursor position. */
                  tp->saved_cx = tp->cx;
                  tp->saved_cy = tp->cy;
                  tp->saved_highlight = tp->highlight;
                  tp->saved_f_color = tp->f_color;
                  break;
            case '8':         /* Restore cursor position. */
                  tty3270_convert_line(tp, tp->cy);
                  tty3270_goto_xy(tp, tp->saved_cx, tp->saved_cy);
                  tp->highlight = tp->saved_highlight;
                  tp->f_color = tp->saved_f_color;
                  break;
            case 'c':         /* Reset terminal. */
                  tp->cx = tp->saved_cx = 0;
                  tp->cy = tp->saved_cy = 0;
                  tp->highlight = tp->saved_highlight = TAX_RESET;
                  tp->f_color = tp->saved_f_color = TAC_RESET;
                  tty3270_erase_display(tp, 2);
                  break;
            }
            return;
      }
      if (tp->esc_state == ESsquare) {
            tp->esc_state = ESgetpars;
            memset(tp->esc_par, 0, sizeof(tp->esc_par));
            tp->esc_npar = 0;
            tp->esc_ques = (ch == '?');
            if (tp->esc_ques)
                  return;
      }
      if (tp->esc_state == ESgetpars) {
            if (ch == ';' && tp->esc_npar < ESCAPE_NPAR - 1) {
                  tp->esc_npar++;
                  return;
            }
            if (ch >= '0' && ch <= '9') {
                  tp->esc_par[tp->esc_npar] *= 10;
                  tp->esc_par[tp->esc_npar] += ch - '0';
                  return;
            }
      }
      tp->esc_state = ESnormal;
      if (ch == 'n' && !tp->esc_ques) {
            if (tp->esc_par[0] == 5)            /* Status report. */
                  kbd_puts_queue(tp->tty, "\033[0n");
            else if (tp->esc_par[0] == 6) {     /* Cursor report. */
                  char buf[40];
                  sprintf(buf, "\033[%d;%dR", tp->cy + 1, tp->cx + 1);
                  kbd_puts_queue(tp->tty, buf);
            }
            return;
      }
      if (tp->esc_ques)
            return;
      switch (ch) {
      case 'm':
            tty3270_set_attributes(tp);
            break;
      case 'H':   /* Set cursor position. */
      case 'f':
            tty3270_goto_xy(tp, tty3270_getpar(tp, 1) - 1,
                        tty3270_getpar(tp, 0) - 1);
            break;
      case 'd':   /* Set y position. */
            tty3270_goto_xy(tp, tp->cx, tty3270_getpar(tp, 0) - 1);
            break;
      case 'A':   /* Cursor up. */
      case 'F':
            tty3270_goto_xy(tp, tp->cx, tp->cy - tty3270_getpar(tp, 0));
            break;
      case 'B':   /* Cursor down. */
      case 'e':
      case 'E':
            tty3270_goto_xy(tp, tp->cx, tp->cy + tty3270_getpar(tp, 0));
            break;
      case 'C':   /* Cursor forward. */
      case 'a':
            tty3270_goto_xy(tp, tp->cx + tty3270_getpar(tp, 0), tp->cy);
            break;
      case 'D':   /* Cursor backward. */
            tty3270_goto_xy(tp, tp->cx - tty3270_getpar(tp, 0), tp->cy);
            break;
      case 'G':   /* Set x position. */
      case '`':
            tty3270_goto_xy(tp, tty3270_getpar(tp, 0), tp->cy);
            break;
      case 'X':   /* Erase Characters. */
            tty3270_erase_characters(tp, tty3270_getpar(tp, 0));
            break;
      case 'J':   /* Erase display. */
            tty3270_erase_display(tp, tp->esc_par[0]);
            break;
      case 'K':   /* Erase line. */
            tty3270_erase_line(tp, tp->esc_par[0]);
            break;
      case 'P':   /* Delete characters. */
            tty3270_delete_characters(tp, tty3270_getpar(tp, 0));
            break;
      case '@':   /* Insert characters. */
            tty3270_insert_characters(tp, tty3270_getpar(tp, 0));
            break;
      case 's':   /* Save cursor position. */
            tp->saved_cx = tp->cx;
            tp->saved_cy = tp->cy;
            tp->saved_highlight = tp->highlight;
            tp->saved_f_color = tp->f_color;
            break;
      case 'u':   /* Restore cursor position. */
            tty3270_convert_line(tp, tp->cy);
            tty3270_goto_xy(tp, tp->saved_cx, tp->saved_cy);
            tp->highlight = tp->saved_highlight;
            tp->f_color = tp->saved_f_color;
            break;
      }
}

/*
 * String write routine for 3270 ttys
 */
static void
tty3270_do_write(struct tty3270 *tp, const unsigned char *buf, int count)
{
      int i_msg, i;

      spin_lock_bh(&tp->view.lock);
      for (i_msg = 0; !tp->tty->stopped && i_msg < count; i_msg++) {
            if (tp->esc_state != 0) {
                  /* Continue escape sequence. */
                  tty3270_escape_sequence(tp, buf[i_msg]);
                  continue;
            }

            switch (buf[i_msg]) {
            case 0x07:        /* '\a' -- Alarm */
                  tp->wcc |= TW_PLUSALARM;
                  break;
            case 0x08:        /* Backspace. */
                  if (tp->cx > 0) {
                        tp->cx--;
                        tty3270_put_character(tp, ' ');
                  }
                  break;
            case 0x09:        /* '\t' -- Tabulate */
                  for (i = tp->cx % 8; i < 8; i++) {
                        if (tp->cx >= tp->view.cols) {
                              tty3270_cr(tp);
                              tty3270_lf(tp);
                              break;
                        }
                        tty3270_put_character(tp, ' ');
                        tp->cx++;
                  }
                  break;
            case 0x0a:        /* '\n' -- New Line */
                  tty3270_cr(tp);
                  tty3270_lf(tp);
                  break;
            case 0x0c:        /* '\f' -- Form Feed */
                  tty3270_erase_display(tp, 2);
                  tp->cx = tp->cy = 0;
                  break;
            case 0x0d:        /* '\r' -- Carriage Return */
                  tp->cx = 0;
                  break;
            case 0x0f:        /* SuSE "exit alternate mode" */
                  break;
            case 0x1b:        /* Start escape sequence. */
                  tty3270_escape_sequence(tp, buf[i_msg]);
                  break;
            default:          /* Insert normal character. */
                  if (tp->cx >= tp->view.cols) {
                        tty3270_cr(tp);
                        tty3270_lf(tp);
                  }
                  tty3270_put_character(tp, buf[i_msg]);
                  tp->cx++;
                  break;
            }
      }
      /* Convert current line to 3270 data fragment. */
      tty3270_convert_line(tp, tp->cy);

      /* Setup timer to update display after 1/10 second */
      if (!timer_pending(&tp->timer))
            tty3270_set_timer(tp, HZ/10);

      spin_unlock_bh(&tp->view.lock);
}

/*
 * String write routine for 3270 ttys
 */
static int
tty3270_write(struct tty_struct * tty,
            const unsigned char *buf, int count)
{
      struct tty3270 *tp;

      tp = tty->driver_data;
      if (!tp)
            return 0;
      if (tp->char_count > 0) {
            tty3270_do_write(tp, tp->char_buf, tp->char_count);
            tp->char_count = 0;
      }
      tty3270_do_write(tp, buf, count);
      return count;
}

/*
 * Put single characters to the ttys character buffer
 */
static void
tty3270_put_char(struct tty_struct *tty, unsigned char ch)
{
      struct tty3270 *tp;

      tp = tty->driver_data;
      if (!tp)
            return;
      if (tp->char_count < TTY3270_CHAR_BUF_SIZE)
            tp->char_buf[tp->char_count++] = ch;
}

/*
 * Flush all characters from the ttys characeter buffer put there
 * by tty3270_put_char.
 */
static void
tty3270_flush_chars(struct tty_struct *tty)
{
      struct tty3270 *tp;

      tp = tty->driver_data;
      if (!tp)
            return;
      if (tp->char_count > 0) {
            tty3270_do_write(tp, tp->char_buf, tp->char_count);
            tp->char_count = 0;
      }
}

/*
 * Returns the number of characters in the output buffer. This is
 * used in tty_wait_until_sent to wait until all characters have
 * appeared on the screen.
 */
static int
tty3270_chars_in_buffer(struct tty_struct *tty)
{
      return 0;
}

static void
tty3270_flush_buffer(struct tty_struct *tty)
{
}

/*
 * Check for visible/invisible input switches
 */
static void
tty3270_set_termios(struct tty_struct *tty, struct ktermios *old)
{
      struct tty3270 *tp;
      int new;

      tp = tty->driver_data;
      if (!tp)
            return;
      spin_lock_bh(&tp->view.lock);
      if (L_ICANON(tty)) {
            new = L_ECHO(tty) ? TF_INPUT: TF_INPUTN;
            if (new != tp->inattr) {
                  tp->inattr = new;
                  tty3270_update_prompt(tp, NULL, 0);
                  tty3270_set_timer(tp, 1);
            }
      }
      spin_unlock_bh(&tp->view.lock);
}

/*
 * Disable reading from a 3270 tty
 */
static void
tty3270_throttle(struct tty_struct * tty)
{
      struct tty3270 *tp;

      tp = tty->driver_data;
      if (!tp)
            return;
      tp->throttle = 1;
}

/*
 * Enable reading from a 3270 tty
 */
static void
tty3270_unthrottle(struct tty_struct * tty)
{
      struct tty3270 *tp;

      tp = tty->driver_data;
      if (!tp)
            return;
      tp->throttle = 0;
      if (tp->attn)
            tty3270_issue_read(tp, 1);
}

/*
 * Hang up the tty device.
 */
static void
tty3270_hangup(struct tty_struct *tty)
{
      // FIXME: implement
}

static void
tty3270_wait_until_sent(struct tty_struct *tty, int timeout)
{
}

static int
tty3270_ioctl(struct tty_struct *tty, struct file *file,
            unsigned int cmd, unsigned long arg)
{
      struct tty3270 *tp;

      tp = tty->driver_data;
      if (!tp)
            return -ENODEV;
      if (tty->flags & (1 << TTY_IO_ERROR))
            return -EIO;
      return kbd_ioctl(tp->kbd, file, cmd, arg);
}

static const struct tty_operations tty3270_ops = {
      .open = tty3270_open,
      .close = tty3270_close,
      .write = tty3270_write,
      .put_char = tty3270_put_char,
      .flush_chars = tty3270_flush_chars,
      .write_room = tty3270_write_room,
      .chars_in_buffer = tty3270_chars_in_buffer,
      .flush_buffer = tty3270_flush_buffer,
      .throttle = tty3270_throttle,
      .unthrottle = tty3270_unthrottle,
      .hangup = tty3270_hangup,
      .wait_until_sent = tty3270_wait_until_sent,
      .ioctl = tty3270_ioctl,
      .set_termios = tty3270_set_termios
};

static void tty3270_notifier(int index, int active)
{
      if (active)
            tty_register_device(tty3270_driver, index, NULL);
      else
            tty_unregister_device(tty3270_driver, index);
}

/*
 * 3270 tty registration code called from tty_init().
 * Most kernel services (incl. kmalloc) are available at this poimt.
 */
static int __init tty3270_init(void)
{
      struct tty_driver *driver;
      int ret;

      driver = alloc_tty_driver(RAW3270_MAXDEVS);
      if (!driver)
            return -ENOMEM;

      /*
       * Initialize the tty_driver structure
       * Entries in tty3270_driver that are NOT initialized:
       * proc_entry, set_termios, flush_buffer, set_ldisc, write_proc
       */
      driver->owner = THIS_MODULE;
      driver->driver_name = "ttyTUB";
      driver->name = "ttyTUB";
      driver->major = IBM_TTY3270_MAJOR;
      driver->minor_start = RAW3270_FIRSTMINOR;
      driver->type = TTY_DRIVER_TYPE_SYSTEM;
      driver->subtype = SYSTEM_TYPE_TTY;
      driver->init_termios = tty_std_termios;
      driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_DYNAMIC_DEV;
      tty_set_operations(driver, &tty3270_ops);
      ret = tty_register_driver(driver);
      if (ret) {
            printk(KERN_ERR "tty3270 registration failed with %d\n", ret);
            put_tty_driver(driver);
            return ret;
      }
      tty3270_driver = driver;
      ret = raw3270_register_notifier(tty3270_notifier);
      if (ret) {
            printk(KERN_ERR "tty3270 notifier registration failed "
                   "with %d\n", ret);
            put_tty_driver(driver);
            return ret;

      }
      return 0;
}

static void __exit
tty3270_exit(void)
{
      struct tty_driver *driver;

      raw3270_unregister_notifier(tty3270_notifier);
      driver = tty3270_driver;
      tty3270_driver = NULL;
      tty_unregister_driver(driver);
      tty3270_del_views();
}

MODULE_LICENSE("GPL");
MODULE_ALIAS_CHARDEV_MAJOR(IBM_TTY3270_MAJOR);

module_init(tty3270_init);
module_exit(tty3270_exit);

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