text: // SPDX-License-Identifier: GPL-2.0
  /*
   * 3215 line mode terminal driver.
   *
   * Copyright IBM Corp. 1999, 2009
   * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
   *
   * Updated:
   *  Aug-2000: Added tab support
   *	      Dan Morrison, IBM Corporation <dmorriso@cse.buffalo.edu>
   */
  
  #include <linux/types.h>
  #include <linux/kdev_t.h>
  #include <linux/tty.h>
  #include <linux/tty_flip.h>
  #include <linux/vt_kern.h>
  #include <linux/init.h>
  #include <linux/console.h>
  #include <linux/interrupt.h>
  #include <linux/err.h>
  #include <linux/reboot.h>
  #include <linux/serial.h> /* ASYNC_* flags */
  #include <linux/slab.h>
  #include <asm/ccwdev.h>
  #include <asm/cio.h>
  #include <asm/io.h>
  #include <asm/ebcdic.h>
  #include <linux/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_WORKING	    4	      /* set if a request is being worked on */
  #define RAW3215_THROTTLED   8	      /* set if reading is disabled */
  #define RAW3215_STOPPED	    16	      /* set if writing is disabled */
  #define RAW3215_TIMER_RUNS  64	      /* set if the output delay timer is on */
  #define RAW3215_FLUSHING    128	      /* set to flush buffer (no delay) */
  
  #define TAB_STOP_SIZE	    8	      /* tab stop size */
  
  /*
   * Request types for a 3215 device
   */
  enum raw3215_type {
  	RAW3215_FREE, RAW3215_READ, RAW3215_WRITE
  };
  
  /*
   * Request structure for a 3215 device
   */
  struct raw3215_req {
  	enum raw3215_type type;	      /* type of the request */
  	int start, len;		      /* start index & len in output buffer */
  	int delayable;		      /* indication to wait for more data */
  	int residual;		      /* residual count for read request */
  	struct ccw1 ccws[RAW3215_NR_CCWS]; /* space for the channel program */
  	struct raw3215_info *info;    /* pointer to main structure */
  	struct raw3215_req *next;     /* pointer to next request */
  } __attribute__ ((aligned(8)));
  
  struct raw3215_info {
  	struct tty_port port;
  	struct ccw_device *cdev;      /* device for tty driver */
  	spinlock_t *lock;	      /* pointer to irq lock */
  	int flags;		      /* state flags */
  	char *buffer;		      /* pointer to output buffer */
  	char *inbuf;		      /* pointer to input buffer */
  	int head;		      /* first free byte in output buffer */
  	int count;		      /* number of bytes in output buffer */
  	int written;		      /* number of bytes in write requests */
  	struct raw3215_req *queued_read; /* pointer to queued read requests */
  	struct raw3215_req *queued_write;/* pointer to queued write requests */
  	struct tasklet_struct tlet;   /* tasklet to invoke tty_wakeup */
  	wait_queue_head_t empty_wait; /* wait queue for flushing */
  	struct timer_list timer;      /* timer for delayed output */
  	int line_pos;		      /* position on the line (for tabs) */
  	char ubuffer[80];	      /* copy_from_user buffer */
  };
  
  /* array of 3215 devices structures */
  static struct raw3215_info *raw3215[NR_3215];
  /* spinlock to protect the raw3215 array */
  static DEFINE_SPINLOCK(raw3215_device_lock);
  /* list of free request structures */
  static struct raw3215_req *raw3215_freelist;
  /* spinlock to protect free list */
  static spinlock_t raw3215_freelist_lock;
  
  static struct tty_driver *tty3215_driver;
  
  /*
   * Get a request structure from the free list
   */
  static inline struct raw3215_req *raw3215_alloc_req(void)
  {
  	struct raw3215_req *req;
  	unsigned long flags;
  
  	spin_lock_irqsave(&raw3215_freelist_lock, flags);
  	req = raw3215_freelist;
  	raw3215_freelist = req->next;
  	spin_unlock_irqrestore(&raw3215_freelist_lock, flags);
  	return req;
  }
  
  /*
   * Put a request structure back to the free list
   */
  static inline void raw3215_free_req(struct raw3215_req *req)
  {
  	unsigned long flags;
  
  	if (req->type == RAW3215_FREE)
  		return;		/* don't free a free request */
  	req->type = RAW3215_FREE;
  	spin_lock_irqsave(&raw3215_freelist_lock, flags);
  	req->next = raw3215_freelist;
  	raw3215_freelist = req;
  	spin_unlock_irqrestore(&raw3215_freelist_lock, flags);
  }
  
  /*
   * Set up a read request that reads up to 160 byte from the 3215 device.
   * If there is a queued read request it is used, but that shouldn't happen
   * because a 3215 terminal won't accept a new read before the old one is
   * completed.
   */
  static void raw3215_mk_read_req(struct raw3215_info *raw)
  {
  	struct raw3215_req *req;
  	struct ccw1 *ccw;
  
  	/* there can only be ONE read request at a time */
  	req = raw->queued_read;
  	if (req == NULL) {
  		/* no queued read request, use new req structure */
  		req = raw3215_alloc_req();
  		req->type = RAW3215_READ;
  		req->info = raw;
  		raw->queued_read = req;
  	}
  
  	ccw = req->ccws;
  	ccw->cmd_code = 0x0A; /* read inquiry */
  	ccw->flags = 0x20;    /* ignore incorrect length */
  	ccw->count = 160;
  	ccw->cda = (__u32) __pa(raw->inbuf);
  }
  
  /*
   * Set up a write request with the information from the main structure.
   * A ccw chain is created that writes as much as possible from the output
   * buffer to the 3215 device. If a queued write exists it is replaced by
   * the new, probably lengthened request.
   */
  static void raw3215_mk_write_req(struct raw3215_info *raw)
  {
  	struct raw3215_req *req;
  	struct ccw1 *ccw;
  	int len, count, ix, lines;
  
  	if (raw->count <= raw->written)
  		return;
  	/* check if there is a queued write request */
  	req = raw->queued_write;
  	if (req == NULL) {
  		/* no queued write request, use new req structure */
  		req = raw3215_alloc_req();
  		req->type = RAW3215_WRITE;
  		req->info = raw;
  		raw->queued_write = req;
  	} else {
  		raw->written -= req->len;
  	}
  
  	ccw = req->ccws;
  	req->start = (raw->head - raw->count + raw->written) &
  		     (RAW3215_BUFFER_SIZE - 1);
  	/*
  	 * now we have to count newlines. We can at max accept
  	 * RAW3215_MAX_NEWLINE newlines in a single ssch due to
  	 * a restriction in VM
  	 */
  	lines = 0;
  	ix = req->start;
  	while (lines < RAW3215_MAX_NEWLINE && ix != raw->head) {
  		if (raw->buffer[ix] == 0x15)
  			lines++;
  		ix = (ix + 1) & (RAW3215_BUFFER_SIZE - 1);
  	}
  	len = ((ix - 1 - req->start) & (RAW3215_BUFFER_SIZE - 1)) + 1;
  	if (len > RAW3215_MAX_BYTES)
  		len = RAW3215_MAX_BYTES;
  	req->len = len;
  	raw->written += len;
  
  	/* set the indication if we should try to enlarge this request */
  	req->delayable = (ix == raw->head) && (len < RAW3215_MIN_WRITE);
  
  	ix = req->start;
  	while (len > 0) {
  		if (ccw > req->ccws)
  			ccw[-1].flags |= 0x40; /* use command chaining */
  		ccw->cmd_code = 0x01; /* write, auto carrier return */
  		ccw->flags = 0x20;    /* ignore incorrect length ind.  */
  		ccw->cda =
  			(__u32) __pa(raw->buffer + ix);
  		count = len;
  		if (ix + count > RAW3215_BUFFER_SIZE)
  			count = RAW3215_BUFFER_SIZE - ix;
  		ccw->count = count;
  		len -= count;
  		ix = (ix + count) & (RAW3215_BUFFER_SIZE - 1);
  		ccw++;
  	}
  	/*
  	 * Add a NOP to the channel program. 3215 devices are purely
  	 * emulated and its much better to avoid the channel end
  	 * interrupt in this case.
  	 */
  	if (ccw > req->ccws)
  		ccw[-1].flags |= 0x40; /* use command chaining */
  	ccw->cmd_code = 0x03; /* NOP */
  	ccw->flags = 0;
  	ccw->cda = 0;
  	ccw->count = 1;
  }
  
  /*
   * Start a read or a write request
   */
  static void raw3215_start_io(struct raw3215_info *raw)
  {
  	struct raw3215_req *req;
  	int res;
  
  	req = raw->queued_read;
  	if (req != NULL &&
  	    !(raw->flags & (RAW3215_WORKING | RAW3215_THROTTLED))) {
  		/* dequeue request */
  		raw->queued_read = NULL;
  		res = ccw_device_start(raw->cdev, req->ccws,
  				       (unsigned long) req, 0, 0);
  		if (res != 0) {
  			/* do_IO failed, put request back to queue */
  			raw->queued_read = req;
  		} else {
  			raw->flags |= RAW3215_WORKING;
  		}
  	}
  	req = raw->queued_write;
  	if (req != NULL &&
  	    !(raw->flags & (RAW3215_WORKING | RAW3215_STOPPED))) {
  		/* dequeue request */
  		raw->queued_write = NULL;
  		res = ccw_device_start(raw->cdev, req->ccws,
  				       (unsigned long) req, 0, 0);
  		if (res != 0) {
  			/* do_IO failed, put request back to queue */
  			raw->queued_write = req;
  		} else {
  			raw->flags |= RAW3215_WORKING;
  		}
  	}
  }
  
  /*
   * Function to start a delayed output after RAW3215_TIMEOUT seconds
   */
  static void raw3215_timeout(unsigned long __data)
  {
  	struct raw3215_info *raw = (struct raw3215_info *) __data;
  	unsigned long flags;
  
  	spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
  	raw->flags &= ~RAW3215_TIMER_RUNS;
  	if (!tty_port_suspended(&raw->port)) {
  		raw3215_mk_write_req(raw);
  		raw3215_start_io(raw);
  		if ((raw->queued_read || raw->queued_write) &&
  		    !(raw->flags & RAW3215_WORKING) &&
  		    !(raw->flags & RAW3215_TIMER_RUNS)) {
  			raw->timer.expires = RAW3215_TIMEOUT + jiffies;
  			add_timer(&raw->timer);
  			raw->flags |= RAW3215_TIMER_RUNS;
  		}
  	}
  	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 (!tty_port_initialized(&raw->port) || tty_port_suspended(&raw->port))
  		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->queued_read || raw->queued_write) &&
  	    !(raw->flags & RAW3215_WORKING) &&
  	    !(raw->flags & RAW3215_TIMER_RUNS)) {
  		raw->timer.expires = RAW3215_TIMEOUT + jiffies;
  		add_timer(&raw->timer);
  		raw->flags |= RAW3215_TIMER_RUNS;
  	}
  }
  
  /*
   * Call tty_wakeup from tasklet context
   */
  static void raw3215_wakeup(unsigned long data)
  {
  	struct raw3215_info *raw = (struct raw3215_info *) data;
  	struct tty_struct *tty;
  
  	tty = tty_port_tty_get(&raw->port);
  	if (tty) {
  		tty_wakeup(tty);
  		tty_kref_put(tty);
  	}
  }
  
  /*
   * Try to start the next IO and wake up processes waiting on the tty.
   */
  static void raw3215_next_io(struct raw3215_info *raw, struct tty_struct *tty)
  {
  	raw3215_mk_write_req(raw);
  	raw3215_try_io(raw);
  	if (tty && RAW3215_BUFFER_SIZE - raw->count >= RAW3215_MIN_SPACE)
  		tasklet_schedule(&raw->tlet);
  }
  
  /*
   * Interrupt routine, called from common io layer
   */
  static void raw3215_irq(struct ccw_device *cdev, unsigned long intparm,
  			struct irb *irb)
  {
  	struct raw3215_info *raw;
  	struct raw3215_req *req;
  	struct tty_struct *tty;
  	int cstat, dstat;
  	int count;
  
  	raw = dev_get_drvdata(&cdev->dev);
  	req = (struct raw3215_req *) intparm;
  	tty = tty_port_tty_get(&raw->port);
  	cstat = irb->scsw.cmd.cstat;
  	dstat = irb->scsw.cmd.dstat;
  	if (cstat != 0)
  		raw3215_next_io(raw, tty);
  	if (dstat & 0x01) { /* we got a unit exception */
  		dstat &= ~0x01;	 /* we can ignore it */
  	}
  	switch (dstat) {
  	case 0x80:
  		if (cstat != 0)
  			break;
  		/* Attention interrupt, someone hit the enter key */
  		raw3215_mk_read_req(raw);
  		raw3215_next_io(raw, tty);
  		break;
  	case 0x08:
  	case 0x0C:
  		/* Channel end interrupt. */
  		if ((raw = req->info) == NULL)
  			goto put_tty;	     /* That shouldn't happen ... */
  		if (req->type == RAW3215_READ) {
  			/* store residual count, then wait for device end */
  			req->residual = irb->scsw.cmd.count;
  		}
  		if (dstat == 0x08)
  			break;
  	case 0x04:
  		/* Device end interrupt. */
  		if ((raw = req->info) == NULL)
  			goto put_tty;	     /* That shouldn't happen ... */
  		if (req->type == RAW3215_READ && tty != NULL) {
  			unsigned int cchar;
  
  			count = 160 - req->residual;
  			EBCASC(raw->inbuf, count);
  			cchar = ctrlchar_handle(raw->inbuf, count, tty);
  			switch (cchar & CTRLCHAR_MASK) {
  			case CTRLCHAR_SYSRQ:
  				break;
  
  			case CTRLCHAR_CTRL:
  				tty_insert_flip_char(&raw->port, cchar,
  						TTY_NORMAL);
  				tty_flip_buffer_push(&raw->port);
  				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(&raw->port, raw->inbuf,
  						count);
  				tty_flip_buffer_push(&raw->port);
  				break;
  			}
  		} else if (req->type == RAW3215_WRITE) {
  			raw->count -= req->len;
  			raw->written -= req->len;
  		}
  		raw->flags &= ~RAW3215_WORKING;
  		raw3215_free_req(req);
  		/* check for empty wait */
  		if (waitqueue_active(&raw->empty_wait) &&
  		    raw->queued_write == NULL &&
  		    raw->queued_read == NULL) {
  			wake_up_interruptible(&raw->empty_wait);
  		}
  		raw3215_next_io(raw, tty);
  		break;
  	default:
  		/* Strange interrupt, I'll do my best to clean up */
  		if (req != NULL && req->type != RAW3215_FREE) {
  			if (req->type == RAW3215_WRITE) {
  				raw->count -= req->len;
  				raw->written -= req->len;
  			}
  			raw->flags &= ~RAW3215_WORKING;
  			raw3215_free_req(req);
  		}
  		raw3215_next_io(raw, tty);
  	}
  put_tty:
  	tty_kref_put(tty);
  }
  
  /*
   * Drop the oldest line from the output buffer.
   */
  static void raw3215_drop_line(struct raw3215_info *raw)
  {
  	int ix;
  	char ch;
  
  	BUG_ON(raw->written != 0);
  	ix = (raw->head - raw->count) & (RAW3215_BUFFER_SIZE - 1);
  	while (raw->count > 0) {
  		ch = raw->buffer[ix];
  		ix = (ix + 1) & (RAW3215_BUFFER_SIZE - 1);
  		raw->count--;
  		if (ch == 0x15)
  			break;
  	}
  	raw->head = ix;
  }
  
  /*
   * Wait until length bytes are available int the output buffer.
   * Has to be called with the s390irq lock held. Can be called
   * disabled.
   */
  static void raw3215_make_room(struct raw3215_info *raw, unsigned int length)
  {
  	while (RAW3215_BUFFER_SIZE - raw->count < length) {
  		/* While console is frozen for suspend we have no other
  		 * choice but to drop message from the buffer to make
  		 * room for even more messages. */
  		if (tty_port_suspended(&raw->port)) {
  			raw3215_drop_line(raw);
  			continue;
  		}
  		/* there might be a request pending */
  		raw->flags |= RAW3215_FLUSHING;
  		raw3215_mk_write_req(raw);
  		raw3215_try_io(raw);
  		raw->flags &= ~RAW3215_FLUSHING;
  #ifdef CONFIG_TN3215_CONSOLE
  		ccw_device_wait_idle(raw->cdev);
  #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 (tty_port_initialized(&raw->port))
  		return 0;
  	raw->line_pos = 0;
  	tty_port_set_initialized(&raw->port, 1);
  	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 (!tty_port_initialized(&raw->port) || (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) {
  		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);
  		tty_port_set_initialized(&raw->port, 1);
  	}
  	spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
  }
  
  static struct raw3215_info *raw3215_alloc_info(void)
  {
  	struct raw3215_info *info;
  
  	info = kzalloc(sizeof(struct raw3215_info), GFP_KERNEL | GFP_DMA);
  	if (!info)
  		return NULL;
  
  	info->buffer = kzalloc(RAW3215_BUFFER_SIZE, GFP_KERNEL | GFP_DMA);
  	info->inbuf = kzalloc(RAW3215_INBUF_SIZE, GFP_KERNEL | GFP_DMA);
  	if (!info->buffer || !info->inbuf) {
  		kfree(info->inbuf);
  		kfree(info->buffer);
  		kfree(info);
  		return NULL;
  	}
  
  	setup_timer(&info->timer, raw3215_timeout, (unsigned long)info);
  	init_waitqueue_head(&info->empty_wait);
  	tasklet_init(&info->tlet, raw3215_wakeup, (unsigned long)info);
  	tty_port_init(&info->port);
  
  	return info;
  }
  
  static void raw3215_free_info(struct raw3215_info *raw)
  {
  	kfree(raw->inbuf);
  	kfree(raw->buffer);
  	tty_port_destroy(&raw->port);
  	kfree(raw);
  }
  
  static int raw3215_probe (struct ccw_device *cdev)
  {
  	struct raw3215_info *raw;
  	int line;
  
  	/* Console is special. */
  	if (raw3215[0] && (raw3215[0] == dev_get_drvdata(&cdev->dev)))
  		return 0;
  
  	raw = raw3215_alloc_info();
  	if (raw == NULL)
  		return -ENOMEM;
  
  	raw->cdev = cdev;
  	dev_set_drvdata(&cdev->dev, raw);
  	cdev->handler = raw3215_irq;
  
  	spin_lock(&raw3215_device_lock);
  	for (line = 0; line < NR_3215; line++) {
  		if (!raw3215[line]) {
  			raw3215[line] = raw;
  			break;
  		}
  	}
  	spin_unlock(&raw3215_device_lock);
  	if (line == NR_3215) {
  		raw3215_free_info(raw);
  		return -ENODEV;
  	}
  
  	return 0;
  }
  
  static void raw3215_remove (struct ccw_device *cdev)
  {
  	struct raw3215_info *raw;
  	unsigned int line;
  
  	ccw_device_set_offline(cdev);
  	raw = dev_get_drvdata(&cdev->dev);
  	if (raw) {
  		spin_lock(&raw3215_device_lock);
  		for (line = 0; line < NR_3215; line++)
  			if (raw3215[line] == raw)
  				break;
  		raw3215[line] = NULL;
  		spin_unlock(&raw3215_device_lock);
  		dev_set_drvdata(&cdev->dev, NULL);
  		raw3215_free_info(raw);
  	}
  }
  
  static int raw3215_set_online (struct ccw_device *cdev)
  {
  	struct raw3215_info *raw;
  
  	raw = dev_get_drvdata(&cdev->dev);
  	if (!raw)
  		return -ENODEV;
  
  	return raw3215_startup(raw);
  }
  
  static int raw3215_set_offline (struct ccw_device *cdev)
  {
  	struct raw3215_info *raw;
  
  	raw = dev_get_drvdata(&cdev->dev);
  	if (!raw)
  		return -ENODEV;
  
  	raw3215_shutdown(raw);
  
  	return 0;
  }
  
  static int raw3215_pm_stop(struct ccw_device *cdev)
  {
  	struct raw3215_info *raw;
  	unsigned long flags;
  
  	/* Empty the output buffer, then prevent new I/O. */
  	raw = dev_get_drvdata(&cdev->dev);
  	spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
  	raw3215_make_room(raw, RAW3215_BUFFER_SIZE);
  	tty_port_set_suspended(&raw->port, 1);
  	spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
  	return 0;
  }
  
  static int raw3215_pm_start(struct ccw_device *cdev)
  {
  	struct raw3215_info *raw;
  	unsigned long flags;
  
  	/* Allow I/O again and flush output buffer. */
  	raw = dev_get_drvdata(&cdev->dev);
  	spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
  	tty_port_set_suspended(&raw->port, 0);
  	raw->flags |= RAW3215_FLUSHING;
  	raw3215_try_io(raw);
  	raw->flags &= ~RAW3215_FLUSHING;
  	spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
  	return 0;
  }
  
  static struct ccw_device_id raw3215_id[] = {
  	{ CCW_DEVICE(0x3215, 0) },
  	{ /* end of list */ },
  };
  
  static struct ccw_driver raw3215_ccw_driver = {
  	.driver = {
  		.name	= "3215",
  		.owner	= THIS_MODULE,
  	},
  	.ids		= raw3215_id,
  	.probe		= &raw3215_probe,
  	.remove		= &raw3215_remove,
  	.set_online	= &raw3215_set_online,
  	.set_offline	= &raw3215_set_offline,
  	.freeze		= &raw3215_pm_stop,
  	.thaw		= &raw3215_pm_start,
  	.restore	= &raw3215_pm_start,
  	.int_class	= IRQIO_C15,
  };
  
  #ifdef CONFIG_TN3215_CONSOLE
  /*
   * Write a string to the 3215 console
   */
  static void con3215_write(struct console *co, const char *str,
  			  unsigned int count)
  {
  	struct raw3215_info *raw;
  	int i;
  
  	if (count <= 0)
  		return;
  	raw = raw3215[0];	/* console 3215 is the first one */
  	while (count > 0) {
  		for (i = 0; i < count; i++)
  			if (str[i] == '\t' || str[i] == '\n')
  				break;
  		raw3215_write(raw, str, i);
  		count -= i;
  		str += i;
  		if (count > 0) {
  			raw3215_putchar(raw, *str);
  			count--;
  			str++;
  		}
  	}
  }
  
  static struct tty_driver *con3215_device(struct console *c, int *index)
  {
  	*index = c->index;
  	return tty3215_driver;
  }
  
  /*
   * panic() calls con3215_flush through a panic_notifier
   * before the system enters a disabled, endless loop.
   */
  static void con3215_flush(void)
  {
  	struct raw3215_info *raw;
  	unsigned long flags;
  
  	raw = raw3215[0];  /* console 3215 is the first one */
  	if (tty_port_suspended(&raw->port))
  		/* The console is still frozen for suspend. */
  		if (ccw_device_force_console(raw->cdev))
  			/* Forcing didn't work, no panic message .. */
  			return;
  	spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
  	raw3215_make_room(raw, RAW3215_BUFFER_SIZE);
  	spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
  }
  
  static int con3215_notify(struct notifier_block *self,
  			  unsigned long event, void *data)
  {
  	con3215_flush();
  	return NOTIFY_OK;
  }
  
  static struct notifier_block on_panic_nb = {
  	.notifier_call = con3215_notify,
  	.priority = 0,
  };
  
  static struct notifier_block on_reboot_nb = {
  	.notifier_call = con3215_notify,
  	.priority = 0,
  };
  
  /*
   *  The console structure for the 3215 console
   */
  static struct console con3215 = {
  	.name	 = "ttyS",
  	.write	 = con3215_write,
  	.device	 = con3215_device,
  	.flags	 = CON_PRINTBUFFER,
  };
  
  /*
   * 3215 console initialization code called from console_init().
   */
  static int __init con3215_init(void)
  {
  	struct ccw_device *cdev;
  	struct raw3215_info *raw;
  	struct raw3215_req *req;
  	int i;
  
  	/* Check if 3215 is to be the console */
  	if (!CONSOLE_IS_3215)
  		return -ENODEV;
  
  	/* Set the console mode for VM */
  	if (MACHINE_IS_VM) {
  		cpcmd("TERM CONMODE 3215", NULL, 0, NULL);
  		cpcmd("TERM AUTOCR OFF", NULL, 0, NULL);
  	}
  
  	/* allocate 3215 request structures */
  	raw3215_freelist = NULL;
  	spin_lock_init(&raw3215_freelist_lock);
  	for (i = 0; i < NR_3215_REQ; i++) {
  		req = kzalloc(sizeof(struct raw3215_req), GFP_KERNEL | GFP_DMA);
  		if (!req)
  			return -ENOMEM;
  		req->next = raw3215_freelist;
  		raw3215_freelist = req;
  	}
  
  	cdev = ccw_device_create_console(&raw3215_ccw_driver);
  	if (IS_ERR(cdev))
  		return -ENODEV;
  
  	raw3215[0] = raw = raw3215_alloc_info();
  	raw->cdev = cdev;
  	dev_set_drvdata(&cdev->dev, raw);
  	cdev->handler = raw3215_irq;
  
  	raw->flags |= RAW3215_FIXED;
  	if (ccw_device_enable_console(cdev)) {
  		ccw_device_destroy_console(cdev);
  		raw3215_free_info(raw);
  		raw3215[0] = NULL;
  		return -ENODEV;
  	}
  
  	/* Request the console irq */
  	if (raw3215_startup(raw) != 0) {
  		raw3215_free_info(raw);
  		raw3215[0] = NULL;
  		return -ENODEV;
  	}
  	atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
  	register_reboot_notifier(&on_reboot_nb);
  	register_console(&con3215);
  	return 0;
  }
  console_initcall(con3215_init);
  #endif
  
  static int tty3215_install(struct tty_driver *driver, struct tty_struct *tty)
  {
  	struct raw3215_info *raw;
  
  	raw = raw3215[tty->index];
  	if (raw == NULL)
  		return -ENODEV;
  
  	tty->driver_data = raw;
  
  	return tty_port_install(&raw->port, driver, tty);
  }
  
  /*
   * tty3215_open
   *
   * This routine is called whenever a 3215 tty is opened.
   */
  static int tty3215_open(struct tty_struct *tty, struct file * filp)
  {
  	struct raw3215_info *raw = tty->driver_data;
  	int retval;
  
  	tty_port_tty_set(&raw->port, tty);
  
  	raw->port.low_latency = 0; /* don't use bottom half for pushing chars */
  	/*
  	 * Start up 3215 device
  	 */
  	retval = raw3215_startup(raw);
  	if (retval)
  		return retval;
  
  	return 0;
  }
  
  /*
   * tty3215_close()
   *
   * This routine is called when the 3215 tty is closed. We wait
   * for the remaining request to be completed. Then we clean up.
   */
  static void tty3215_close(struct tty_struct *tty, struct file * filp)
  {
  	struct raw3215_info *raw;
  
  	raw = (struct raw3215_info *) tty->driver_data;
  	if (raw == NULL || tty->count > 1)
  		return;
  	tty->closing = 1;
  	/* Shutdown the terminal */
  	raw3215_shutdown(raw);
  	tasklet_kill(&raw->tlet);
  	tty->closing = 0;
  	tty_port_tty_set(&raw->port, NULL);
  }
  
  /*
   * Returns the amount of free space in the output buffer.
   */
  static int tty3215_write_room(struct tty_struct *tty)
  {
  	struct raw3215_info *raw;
  
  	raw = (struct raw3215_info *) tty->driver_data;
  
  	/* Subtract TAB_STOP_SIZE to allow for a tab, 8 <<< 64K */
  	if ((RAW3215_BUFFER_SIZE - raw->count - TAB_STOP_SIZE) >= 0)
  		return RAW3215_BUFFER_SIZE - raw->count - TAB_STOP_SIZE;
  	else
  		return 0;
  }
  
  /*
   * String write routine for 3215 ttys
   */
  static int tty3215_write(struct tty_struct * tty,
  			 const unsigned char *buf, int count)
  {
  	struct raw3215_info *raw;
  	int i, written;
  
  	if (!tty)
  		return 0;
  	raw = (struct raw3215_info *) tty->driver_data;
  	written = count;
  	while (count > 0) {
  		for (i = 0; i < count; i++)
  			if (buf[i] == '\t' || buf[i] == '\n')
  				break;
  		raw3215_write(raw, buf, i);
  		count -= i;
  		buf += i;
  		if (count > 0) {
  			raw3215_putchar(raw, *buf);
  			count--;
  			buf++;
  		}
  	}
  	return written;
  }
  
  /*
   * Put character routine for 3215 ttys
   */
  static int tty3215_put_char(struct tty_struct *tty, unsigned char ch)
  {
  	struct raw3215_info *raw;
  
  	if (!tty)
  		return 0;
  	raw = (struct raw3215_info *) tty->driver_data;
  	raw3215_putchar(raw, ch);
  	return 1;
  }
  
  static void tty3215_flush_chars(struct tty_struct *tty)
  {
  }
  
  /*
   * Returns the number of characters in the output buffer
   */
  static int tty3215_chars_in_buffer(struct tty_struct *tty)
  {
  	struct raw3215_info *raw;
  
  	raw = (struct raw3215_info *) tty->driver_data;
  	return raw->count;
  }
  
  static void tty3215_flush_buffer(struct tty_struct *tty)
  {
  	struct raw3215_info *raw;
  
  	raw = (struct raw3215_info *) tty->driver_data;
  	raw3215_flush_buffer(raw);
  	tty_wakeup(tty);
  }
  
  /*
   * Disable reading from a 3215 tty
   */
  static void tty3215_throttle(struct tty_struct * tty)
  {
  	struct raw3215_info *raw;
  
  	raw = (struct raw3215_info *) tty->driver_data;
  	raw->flags |= RAW3215_THROTTLED;
  }
  
  /*
   * Enable reading from a 3215 tty
   */
  static void tty3215_unthrottle(struct tty_struct * tty)
  {
  	struct raw3215_info *raw;
  	unsigned long flags;
  
  	raw = (struct raw3215_info *) tty->driver_data;
  	if (raw->flags & RAW3215_THROTTLED) {
  		spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
  		raw->flags &= ~RAW3215_THROTTLED;
  		raw3215_try_io(raw);
  		spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
  	}
  }
  
  /*
   * Disable writing to a 3215 tty
   */
  static void tty3215_stop(struct tty_struct *tty)
  {
  	struct raw3215_info *raw;
  
  	raw = (struct raw3215_info *) tty->driver_data;
  	raw->flags |= RAW3215_STOPPED;
  }
  
  /*
   * Enable writing to a 3215 tty
   */
  static void tty3215_start(struct tty_struct *tty)
  {
  	struct raw3215_info *raw;
  	unsigned long flags;
  
  	raw = (struct raw3215_info *) tty->driver_data;
  	if (raw->flags & RAW3215_STOPPED) {
  		spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
  		raw->flags &= ~RAW3215_STOPPED;
  		raw3215_try_io(raw);
  		spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
  	}
  }
  
  static const struct tty_operations tty3215_ops = {
  	.install = tty3215_install,
  	.open = tty3215_open,
  	.close = tty3215_close,
  	.write = tty3215_write,
  	.put_char = tty3215_put_char,
  	.flush_chars = tty3215_flush_chars,
  	.write_room = tty3215_write_room,
  	.chars_in_buffer = tty3215_chars_in_buffer,
  	.flush_buffer = tty3215_flush_buffer,
  	.throttle = tty3215_throttle,
  	.unthrottle = tty3215_unthrottle,
  	.stop = tty3215_stop,
  	.start = tty3215_start,
  };
  
  /*
   * 3215 tty registration code called from tty_init().
   * Most kernel services (incl. kmalloc) are available at this poimt.
   */
  static int __init tty3215_init(void)
  {
  	struct tty_driver *driver;
  	int ret;
  
  	if (!CONSOLE_IS_3215)
  		return 0;
  
  	driver = alloc_tty_driver(NR_3215);
  	if (!driver)
  		return -ENOMEM;
  
  	ret = ccw_driver_register(&raw3215_ccw_driver);
  	if (ret) {
  		put_tty_driver(driver);
  		return ret;
  	}
  	/*
  	 * Initialize the tty_driver structure
  	 * Entries in tty3215_driver that are NOT initialized:
  	 * proc_entry, set_termios, flush_buffer, set_ldisc, write_proc
  	 */
  
  	driver->driver_name = "tty3215";
  	driver->name = "ttyS";
  	driver->major = TTY_MAJOR;
  	driver->minor_start = 64;
  	driver->type = TTY_DRIVER_TYPE_SYSTEM;
  	driver->subtype = SYSTEM_TYPE_TTY;
  	driver->init_termios = tty_std_termios;
  	driver->init_termios.c_iflag = IGNBRK | IGNPAR;
  	driver->init_termios.c_oflag = ONLCR;
  	driver->init_termios.c_lflag = ISIG;
  	driver->flags = TTY_DRIVER_REAL_RAW;
  	tty_set_operations(driver, &tty3215_ops);
  	ret = tty_register_driver(driver);
  	if (ret) {
  		put_tty_driver(driver);
  		return ret;
  	}
  	tty3215_driver = driver;
  	return 0;
  }
  device_initcall(tty3215_init);
  