/*
   * IBM/3270 Driver - console view.
   *
   * 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 IBM Corp. 2003, 2009
   */
  
  #include <linux/console.h>
  #include <linux/init.h>
  #include <linux/interrupt.h>
  #include <linux/list.h>
  #include <linux/types.h>
  #include <linux/slab.h>
  #include <linux/err.h>
  #include <linux/reboot.h>
  
  #include <asm/ccwdev.h>
  #include <asm/cio.h>
  #include <asm/cpcmd.h>
  #include <asm/ebcdic.h>
  
  #include "raw3270.h"
  #include "tty3270.h"
  #include "ctrlchar.h"
  
  #define CON3270_OUTPUT_BUFFER_SIZE 1024
  #define CON3270_STRING_PAGES 4
  
  static struct raw3270_fn con3270_fn;
  
  /*
   * Main 3270 console view data structure.
   */
  struct con3270 {
  	struct raw3270_view view;
  	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. */
  	int line_nr;			/* line number for next update. */
  	int nr_lines;			/* # lines in list. */
  	int nr_up;			/* # lines up in history. */
  	unsigned long update_flags;	/* Update indication bits. */
  	struct string *cline;		/* current output line. */
  	struct string *status;		/* last line of display. */
  	struct raw3270_request *write;	/* single write request. */
  	struct timer_list timer;
  
  	/* Input stuff. */
  	struct string *input;		/* input string for read request. */
  	struct raw3270_request *read;	/* single read request. */
  	struct raw3270_request *kreset;	/* single keyboard reset request. */
  	struct tasklet_struct readlet;	/* tasklet to issue read request. */
  };
  
  static struct con3270 *condev;
  
  /* con3270->update_flags. See con3270_update for details. */
  #define CON_UPDATE_ERASE	1	/* Use EWRITEA instead of WRITE. */
  #define CON_UPDATE_LIST		2	/* Update lines in tty3270->update. */
  #define CON_UPDATE_STATUS	4	/* Update status line. */
  #define CON_UPDATE_ALL		8	/* Recreate screen. */
  
  static void con3270_update(struct con3270 *);
  
  /*
   * Setup timeout for a device. On timeout trigger an update.
   */
  static void con3270_set_timer(struct con3270 *cp, int expires)
  {
  	if (expires == 0)
  		del_timer(&cp->timer);
  	else
  		mod_timer(&cp->timer, jiffies + expires);
  }
  
  /*
   * The status line is the last line of the screen. It shows the string
   * "console view" in the lower left corner and "Running"/"More..."/"Holding"
   * in the lower right corner of the screen.
   */
  static void
  con3270_update_status(struct con3270 *cp)
  {
  	char *str;
  
  	str = (cp->nr_up != 0) ? "History" : "Running";
  	memcpy(cp->status->string + 24, str, 7);
  	codepage_convert(cp->view.ascebc, cp->status->string + 24, 7);
  	cp->update_flags |= CON_UPDATE_STATUS;
  }
  
  static void
  con3270_create_status(struct con3270 *cp)
  {
  	static const unsigned char blueprint[] =
  		{ TO_SBA, 0, 0, TO_SF,TF_LOG,TO_SA,TAT_COLOR, TAC_GREEN,
  		  'c','o','n','s','o','l','e',' ','v','i','e','w',
  		  TO_RA,0,0,0,'R','u','n','n','i','n','g',TO_SF,TF_LOG };
  
  	cp->status = alloc_string(&cp->freemem, sizeof(blueprint));
  	/* Copy blueprint to status line */
  	memcpy(cp->status->string, blueprint, sizeof(blueprint));
  	/* Set TO_RA addresses. */
  	raw3270_buffer_address(cp->view.dev, cp->status->string + 1,
  			       cp->view.cols * (cp->view.rows - 1));
  	raw3270_buffer_address(cp->view.dev, cp->status->string + 21,
  			       cp->view.cols * cp->view.rows - 8);
  	/* Convert strings to ebcdic. */
  	codepage_convert(cp->view.ascebc, cp->status->string + 8, 12);
  	codepage_convert(cp->view.ascebc, cp->status->string + 24, 7);
  }
  
  /*
   * Set output offsets to 3270 datastream fragment of a console string.
   */
  static void
  con3270_update_string(struct con3270 *cp, struct string *s, int nr)
  {
  	if (s->len >= cp->view.cols - 5)
  		return;
  	raw3270_buffer_address(cp->view.dev, s->string + s->len - 3,
  			       cp->view.cols * (nr + 1));
  }
  
  /*
   * Rebuild update list to print all lines.
   */
  static void
  con3270_rebuild_update(struct con3270 *cp)
  {
  	struct string *s, *n;
  	int nr;
  
  	/* 
  	 * 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, &cp->update, update)
  		list_del_init(&s->update);
  	nr = cp->view.rows - 2 + cp->nr_up;
  	list_for_each_entry_reverse(s, &cp->lines, list) {
  		if (nr < cp->view.rows - 1)
  			list_add(&s->update, &cp->update);
  		if (--nr < 0)
  			break;
  	}
  	cp->line_nr = 0;
  	cp->update_flags |= CON_UPDATE_LIST;
  }
  
  /*
   * Alloc string for size bytes. Free strings from history if necessary.
   */
  static struct string *
  con3270_alloc_string(struct con3270 *cp, size_t size)
  {
  	struct string *s, *n;
  
  	s = alloc_string(&cp->freemem, size);
  	if (s)
  		return s;
  	list_for_each_entry_safe(s, n, &cp->lines, list) {
  		list_del(&s->list);
  		if (!list_empty(&s->update))
  			list_del(&s->update);
  		cp->nr_lines--;
  		if (free_string(&cp->freemem, s) >= size)
  			break;
  	}
  	s = alloc_string(&cp->freemem, size);
  	BUG_ON(!s);
  	if (cp->nr_up != 0 && cp->nr_up + cp->view.rows > cp->nr_lines) {
  		cp->nr_up = cp->nr_lines - cp->view.rows + 1;
  		con3270_rebuild_update(cp);
  		con3270_update_status(cp);
  	}
  	return s;
  }
  
  /*
   * Write completion callback.
   */
  static void
  con3270_write_callback(struct raw3270_request *rq, void *data)
  {
  	raw3270_request_reset(rq);
  	xchg(&((struct con3270 *) rq->view)->write, rq);
  }
  
  /*
   * Update console display.
   */
  static void
  con3270_update(struct con3270 *cp)
  {
  	struct raw3270_request *wrq;
  	char wcc, prolog[6];
  	unsigned long flags;
  	unsigned long updated;
  	struct string *s, *n;
  	int rc;
  
  	if (cp->view.dev)
  		raw3270_activate_view(&cp->view);
  
  	wrq = xchg(&cp->write, 0);
  	if (!wrq) {
  		con3270_set_timer(cp, 1);
  		return;
  	}
  
  	spin_lock_irqsave(&cp->view.lock, flags);
  	updated = 0;
  	if (cp->update_flags & CON_UPDATE_ALL) {
  		con3270_rebuild_update(cp);
  		con3270_update_status(cp);
  		cp->update_flags = CON_UPDATE_ERASE | CON_UPDATE_LIST |
  			CON_UPDATE_STATUS;
  	}
  	if (cp->update_flags & CON_UPDATE_ERASE) {
  		/* Use erase write alternate to initialize display. */
  		raw3270_request_set_cmd(wrq, TC_EWRITEA);
  		updated |= CON_UPDATE_ERASE;
  	} else
  		raw3270_request_set_cmd(wrq, TC_WRITE);
  
  	wcc = TW_NONE;
  	raw3270_request_add_data(wrq, &wcc, 1);
  
  	/*
  	 * Update status line.
  	 */
  	if (cp->update_flags & CON_UPDATE_STATUS)
  		if (raw3270_request_add_data(wrq, cp->status->string,
  					     cp->status->len) == 0)
  			updated |= CON_UPDATE_STATUS;
  
  	if (cp->update_flags & CON_UPDATE_LIST) {
  		prolog[0] = TO_SBA;
  		prolog[3] = TO_SA;
  		prolog[4] = TAT_COLOR;
  		prolog[5] = TAC_TURQ;
  		raw3270_buffer_address(cp->view.dev, prolog + 1,
  				       cp->view.cols * cp->line_nr);
  		raw3270_request_add_data(wrq, prolog, 6);
  		/* Write strings in the update list to the screen. */
  		list_for_each_entry_safe(s, n, &cp->update, update) {
  			if (s != cp->cline)
  				con3270_update_string(cp, s, cp->line_nr);
  			if (raw3270_request_add_data(wrq, s->string,
  						     s->len) != 0)
  				break;
  			list_del_init(&s->update);
  			if (s != cp->cline)
  				cp->line_nr++;
  		}
  		if (list_empty(&cp->update))
  			updated |= CON_UPDATE_LIST;
  	}
  	wrq->callback = con3270_write_callback;
  	rc = raw3270_start(&cp->view, wrq);
  	if (rc == 0) {
  		cp->update_flags &= ~updated;
  		if (cp->update_flags)
  			con3270_set_timer(cp, 1);
  	} else {
  		raw3270_request_reset(wrq);
  		xchg(&cp->write, wrq);
  	}
  	spin_unlock_irqrestore(&cp->view.lock, flags);
  }
  
  /*
   * Read tasklet.
   */
  static void
  con3270_read_tasklet(struct raw3270_request *rrq)
  {
  	static char kreset_data = TW_KR;
  	struct con3270 *cp;
  	unsigned long flags;
  	int nr_up, deactivate;
  
  	cp = (struct con3270 *) rrq->view;
  	spin_lock_irqsave(&cp->view.lock, flags);
  	nr_up = cp->nr_up;
  	deactivate = 0;
  	/* Check aid byte. */
  	switch (cp->input->string[0]) {
  	case 0x7d:	/* enter: jump to bottom. */
  		nr_up = 0;
  		break;
  	case 0xf3:	/* PF3: deactivate the console view. */
  		deactivate = 1;
  		break;
  	case 0x6d:	/* clear: start from scratch. */
  		cp->update_flags = CON_UPDATE_ALL;
  		con3270_set_timer(cp, 1);
  		break;
  	case 0xf7:	/* PF7: do a page up in the console log. */
  		nr_up += cp->view.rows - 2;
  		if (nr_up + cp->view.rows - 1 > cp->nr_lines) {
  			nr_up = cp->nr_lines - cp->view.rows + 1;
  			if (nr_up < 0)
  				nr_up = 0;
  		}
  		break;
  	case 0xf8:	/* PF8: do a page down in the console log. */
  		nr_up -= cp->view.rows - 2;
  		if (nr_up < 0)
  			nr_up = 0;
  		break;
  	}
  	if (nr_up != cp->nr_up) {
  		cp->nr_up = nr_up;
  		con3270_rebuild_update(cp);
  		con3270_update_status(cp);
  		con3270_set_timer(cp, 1);
  	}
  	spin_unlock_irqrestore(&cp->view.lock, flags);
  
  	/* Start keyboard reset command. */
  	raw3270_request_reset(cp->kreset);
  	raw3270_request_set_cmd(cp->kreset, TC_WRITE);
  	raw3270_request_add_data(cp->kreset, &kreset_data, 1);
  	raw3270_start(&cp->view, cp->kreset);
  
  	if (deactivate)
  		raw3270_deactivate_view(&cp->view);
  
  	raw3270_request_reset(rrq);
  	xchg(&cp->read, rrq);
  	raw3270_put_view(&cp->view);
  }
  
  /*
   * Read request completion callback.
   */
  static void
  con3270_read_callback(struct raw3270_request *rq, void *data)
  {
  	raw3270_get_view(rq->view);
  	/* Schedule tasklet to pass input to tty. */
  	tasklet_schedule(&((struct con3270 *) rq->view)->readlet);
  }
  
  /*
   * Issue a read request. Called only from interrupt function.
   */
  static void
  con3270_issue_read(struct con3270 *cp)
  {
  	struct raw3270_request *rrq;
  	int rc;
  
  	rrq = xchg(&cp->read, 0);
  	if (!rrq)
  		/* Read already scheduled. */
  		return;
  	rrq->callback = con3270_read_callback;
  	rrq->callback_data = cp;
  	raw3270_request_set_cmd(rrq, TC_READMOD);
  	raw3270_request_set_data(rrq, cp->input->string, cp->input->len);
  	/* Issue the read modified request. */
  	rc = raw3270_start_irq(&cp->view, rrq);
  	if (rc)
  		raw3270_request_reset(rrq);
  }
  
  /*
   * Switch to the console view.
   */
  static int
  con3270_activate(struct raw3270_view *view)
  {
  	struct con3270 *cp;
  
  	cp = (struct con3270 *) view;
  	cp->update_flags = CON_UPDATE_ALL;
  	con3270_set_timer(cp, 1);
  	return 0;
  }
  
  static void
  con3270_deactivate(struct raw3270_view *view)
  {
  	struct con3270 *cp;
  
  	cp = (struct con3270 *) view;
  	del_timer(&cp->timer);
  }
  
  static int
  con3270_irq(struct con3270 *cp, struct raw3270_request *rq, struct irb *irb)
  {
  	/* Handle ATTN. Schedule tasklet to read aid. */
  	if (irb->scsw.cmd.dstat & DEV_STAT_ATTENTION)
  		con3270_issue_read(cp);
  
  	if (rq) {
  		if (irb->scsw.cmd.dstat & DEV_STAT_UNIT_CHECK)
  			rq->rc = -EIO;
  		else
  			/* Normal end. Copy residual count. */
  			rq->rescnt = irb->scsw.cmd.count;
  	}
  	return RAW3270_IO_DONE;
  }
  
  /* Console view to a 3270 device. */
  static struct raw3270_fn con3270_fn = {
  	.activate = con3270_activate,
  	.deactivate = con3270_deactivate,
  	.intv = (void *) con3270_irq
  };
  
  static inline void
  con3270_cline_add(struct con3270 *cp)
  {
  	if (!list_empty(&cp->cline->list))
  		/* Already added. */
  		return;
  	list_add_tail(&cp->cline->list, &cp->lines);
  	cp->nr_lines++;
  	con3270_rebuild_update(cp);
  }
  
  static inline void
  con3270_cline_insert(struct con3270 *cp, unsigned char c)
  {
  	cp->cline->string[cp->cline->len++] = 
  		cp->view.ascebc[(c < ' ') ? ' ' : c];
  	if (list_empty(&cp->cline->update)) {
  		list_add_tail(&cp->cline->update, &cp->update);
  		cp->update_flags |= CON_UPDATE_LIST;
  	}
  }
  
  static inline void
  con3270_cline_end(struct con3270 *cp)
  {
  	struct string *s;
  	unsigned int size;
  
  	/* Copy cline. */
  	size = (cp->cline->len < cp->view.cols - 5) ?
  		cp->cline->len + 4 : cp->view.cols;
  	s = con3270_alloc_string(cp, size);
  	memcpy(s->string, cp->cline->string, cp->cline->len);
  	if (s->len < cp->view.cols - 5) {
  		s->string[s->len - 4] = TO_RA;
  		s->string[s->len - 1] = 0;
  	} else {
  		while (--size > cp->cline->len)
  			s->string[size] = cp->view.ascebc[' '];
  	}
  	/* Replace cline with allocated line s and reset cline. */
  	list_add(&s->list, &cp->cline->list);
  	list_del_init(&cp->cline->list);
  	if (!list_empty(&cp->cline->update)) {
  		list_add(&s->update, &cp->cline->update);
  		list_del_init(&cp->cline->update);
  	}
  	cp->cline->len = 0;
  }
  
  /*
   * Write a string to the 3270 console
   */
  static void
  con3270_write(struct console *co, const char *str, unsigned int count)
  {
  	struct con3270 *cp;
  	unsigned long flags;
  	unsigned char c;
  
  	cp = condev;
  	spin_lock_irqsave(&cp->view.lock, flags);
  	while (count-- > 0) {
  		c = *str++;
  		if (cp->cline->len == 0)
  			con3270_cline_add(cp);
  		if (c != '
  ')
  			con3270_cline_insert(cp, c);
  		if (c == '
  ' || cp->cline->len >= cp->view.cols)
  			con3270_cline_end(cp);
  	}
  	/* Setup timer to output current console buffer after 1/10 second */
  	cp->nr_up = 0;
  	if (cp->view.dev && !timer_pending(&cp->timer))
  		con3270_set_timer(cp, HZ/10);
  	spin_unlock_irqrestore(&cp->view.lock,flags);
  }
  
  static struct tty_driver *
  con3270_device(struct console *c, int *index)
  {
  	*index = c->index;
  	return tty3270_driver;
  }
  
  /*
   * Wait for end of write request.
   */
  static void
  con3270_wait_write(struct con3270 *cp)
  {
  	while (!cp->write) {
  		raw3270_wait_cons_dev(cp->view.dev);
  		barrier();
  	}
  }
  
  /*
   * panic() calls con3270_flush through a panic_notifier
   * before the system enters a disabled, endless loop.
   */
  static void
  con3270_flush(void)
  {
  	struct con3270 *cp;
  	unsigned long flags;
  
  	cp = condev;
  	if (!cp->view.dev)
  		return;
  	raw3270_pm_unfreeze(&cp->view);
  	spin_lock_irqsave(&cp->view.lock, flags);
  	con3270_wait_write(cp);
  	cp->nr_up = 0;
  	con3270_rebuild_update(cp);
  	con3270_update_status(cp);
  	while (cp->update_flags != 0) {
  		spin_unlock_irqrestore(&cp->view.lock, flags);
  		con3270_update(cp);
  		spin_lock_irqsave(&cp->view.lock, flags);
  		con3270_wait_write(cp);
  	}
  	spin_unlock_irqrestore(&cp->view.lock, flags);
  }
  
  static int con3270_notify(struct notifier_block *self,
  			  unsigned long event, void *data)
  {
  	con3270_flush();
  	return NOTIFY_OK;
  }
  
  static struct notifier_block on_panic_nb = {
  	.notifier_call = con3270_notify,
  	.priority = 0,
  };
  
  static struct notifier_block on_reboot_nb = {
  	.notifier_call = con3270_notify,
  	.priority = 0,
  };
  
  /*
   *  The console structure for the 3270 console
   */
  static struct console con3270 = {
  	.name	 = "tty3270",
  	.write	 = con3270_write,
  	.device	 = con3270_device,
  	.flags	 = CON_PRINTBUFFER,
  };
  
  /*
   * 3270 console initialization code called from console_init().
   */
  static int __init
  con3270_init(void)
  {
  	struct raw3270 *rp;
  	void *cbuf;
  	int i;
  
  	/* Check if 3270 is to be the console */
  	if (!CONSOLE_IS_3270)
  		return -ENODEV;
  
  	/* Set the console mode for VM */
  	if (MACHINE_IS_VM) {
  		cpcmd("TERM CONMODE 3270", NULL, 0, NULL);
  		cpcmd("TERM AUTOCR OFF", NULL, 0, NULL);
  	}
  
  	rp = raw3270_setup_console();
  	if (IS_ERR(rp))
  		return PTR_ERR(rp);
  
  	condev = kzalloc(sizeof(struct con3270), GFP_KERNEL | GFP_DMA);
  	condev->view.dev = rp;
  
  	condev->read = raw3270_request_alloc(0);
  	condev->read->callback = con3270_read_callback;
  	condev->read->callback_data = condev;
  	condev->write = raw3270_request_alloc(CON3270_OUTPUT_BUFFER_SIZE);
  	condev->kreset = raw3270_request_alloc(1);
  
  	INIT_LIST_HEAD(&condev->lines);
  	INIT_LIST_HEAD(&condev->update);
  	setup_timer(&condev->timer, (void (*)(unsigned long)) con3270_update,
  		    (unsigned long) condev);
  	tasklet_init(&condev->readlet, 
  		     (void (*)(unsigned long)) con3270_read_tasklet,
  		     (unsigned long) condev->read);
  
  	raw3270_add_view(&condev->view, &con3270_fn, 1);
  
  	INIT_LIST_HEAD(&condev->freemem);
  	for (i = 0; i < CON3270_STRING_PAGES; i++) {
  		cbuf = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
  		add_string_memory(&condev->freemem, cbuf, PAGE_SIZE);
  	}
  	condev->cline = alloc_string(&condev->freemem, condev->view.cols);
  	condev->cline->len = 0;
  	con3270_create_status(condev);
  	condev->input = alloc_string(&condev->freemem, 80);
  	atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
  	register_reboot_notifier(&on_reboot_nb);
  	register_console(&con3270);
  	return 0;
  }
  
  console_initcall(con3270_init);