xref: /openbmc/linux/drivers/s390/char/con3215.c (revision 9a29f5fc)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * 3215 line mode terminal driver.
4  *
5  * Copyright IBM Corp. 1999, 2009
6  * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
7  *
8  * Updated:
9  *  Aug-2000: Added tab support
10  *	      Dan Morrison, IBM Corporation <dmorriso@cse.buffalo.edu>
11  */
12 
13 #include <linux/types.h>
14 #include <linux/kdev_t.h>
15 #include <linux/tty.h>
16 #include <linux/tty_flip.h>
17 #include <linux/vt_kern.h>
18 #include <linux/init.h>
19 #include <linux/console.h>
20 #include <linux/interrupt.h>
21 #include <linux/err.h>
22 #include <linux/panic_notifier.h>
23 #include <linux/reboot.h>
24 #include <linux/serial.h> /* ASYNC_* flags */
25 #include <linux/slab.h>
26 #include <asm/ccwdev.h>
27 #include <asm/cio.h>
28 #include <asm/io.h>
29 #include <asm/ebcdic.h>
30 #include <linux/uaccess.h>
31 #include <asm/delay.h>
32 #include <asm/cpcmd.h>
33 #include <asm/setup.h>
34 
35 #include "ctrlchar.h"
36 
37 #define NR_3215		    1
38 #define NR_3215_REQ	    (4*NR_3215)
39 #define RAW3215_BUFFER_SIZE 65536     /* output buffer size */
40 #define RAW3215_INBUF_SIZE  256	      /* input buffer size */
41 #define RAW3215_MIN_SPACE   128	      /* minimum free space for wakeup */
42 #define RAW3215_MIN_WRITE   1024      /* min. length for immediate output */
43 #define RAW3215_MAX_BYTES   3968      /* max. bytes to write with one ssch */
44 #define RAW3215_MAX_NEWLINE 50	      /* max. lines to write with one ssch */
45 #define RAW3215_NR_CCWS	    3
46 #define RAW3215_TIMEOUT	    HZ/10     /* time for delayed output */
47 
48 #define RAW3215_FIXED	    1	      /* 3215 console device is not be freed */
49 #define RAW3215_WORKING	    4	      /* set if a request is being worked on */
50 #define RAW3215_THROTTLED   8	      /* set if reading is disabled */
51 #define RAW3215_STOPPED	    16	      /* set if writing is disabled */
52 #define RAW3215_TIMER_RUNS  64	      /* set if the output delay timer is on */
53 #define RAW3215_FLUSHING    128	      /* set to flush buffer (no delay) */
54 
55 #define TAB_STOP_SIZE	    8	      /* tab stop size */
56 
57 /*
58  * Request types for a 3215 device
59  */
60 enum raw3215_type {
61 	RAW3215_FREE, RAW3215_READ, RAW3215_WRITE
62 };
63 
64 /*
65  * Request structure for a 3215 device
66  */
67 struct raw3215_req {
68 	enum raw3215_type type;	      /* type of the request */
69 	int start, len;		      /* start index & len in output buffer */
70 	int delayable;		      /* indication to wait for more data */
71 	int residual;		      /* residual count for read request */
72 	struct ccw1 ccws[RAW3215_NR_CCWS]; /* space for the channel program */
73 	struct raw3215_info *info;    /* pointer to main structure */
74 	struct raw3215_req *next;     /* pointer to next request */
75 } __attribute__ ((aligned(8)));
76 
77 struct raw3215_info {
78 	struct tty_port port;
79 	struct ccw_device *cdev;      /* device for tty driver */
80 	spinlock_t *lock;	      /* pointer to irq lock */
81 	int flags;		      /* state flags */
82 	char *buffer;		      /* pointer to output buffer */
83 	char *inbuf;		      /* pointer to input buffer */
84 	int head;		      /* first free byte in output buffer */
85 	int count;		      /* number of bytes in output buffer */
86 	int written;		      /* number of bytes in write requests */
87 	struct raw3215_req *queued_read; /* pointer to queued read requests */
88 	struct raw3215_req *queued_write;/* pointer to queued write requests */
89 	wait_queue_head_t empty_wait; /* wait queue for flushing */
90 	struct timer_list timer;      /* timer for delayed output */
91 	int line_pos;		      /* position on the line (for tabs) */
92 	char ubuffer[80];	      /* copy_from_user buffer */
93 };
94 
95 /* array of 3215 devices structures */
96 static struct raw3215_info *raw3215[NR_3215];
97 /* spinlock to protect the raw3215 array */
98 static DEFINE_SPINLOCK(raw3215_device_lock);
99 /* list of free request structures */
100 static struct raw3215_req *raw3215_freelist;
101 /* spinlock to protect free list */
102 static DEFINE_SPINLOCK(raw3215_freelist_lock);
103 
104 static struct tty_driver *tty3215_driver;
105 
106 /*
107  * Get a request structure from the free list
108  */
109 static inline struct raw3215_req *raw3215_alloc_req(void)
110 {
111 	struct raw3215_req *req;
112 	unsigned long flags;
113 
114 	spin_lock_irqsave(&raw3215_freelist_lock, flags);
115 	req = raw3215_freelist;
116 	raw3215_freelist = req->next;
117 	spin_unlock_irqrestore(&raw3215_freelist_lock, flags);
118 	return req;
119 }
120 
121 /*
122  * Put a request structure back to the free list
123  */
124 static inline void raw3215_free_req(struct raw3215_req *req)
125 {
126 	unsigned long flags;
127 
128 	if (req->type == RAW3215_FREE)
129 		return;		/* don't free a free request */
130 	req->type = RAW3215_FREE;
131 	spin_lock_irqsave(&raw3215_freelist_lock, flags);
132 	req->next = raw3215_freelist;
133 	raw3215_freelist = req;
134 	spin_unlock_irqrestore(&raw3215_freelist_lock, flags);
135 }
136 
137 /*
138  * Set up a read request that reads up to 160 byte from the 3215 device.
139  * If there is a queued read request it is used, but that shouldn't happen
140  * because a 3215 terminal won't accept a new read before the old one is
141  * completed.
142  */
143 static void raw3215_mk_read_req(struct raw3215_info *raw)
144 {
145 	struct raw3215_req *req;
146 	struct ccw1 *ccw;
147 
148 	/* there can only be ONE read request at a time */
149 	req = raw->queued_read;
150 	if (req == NULL) {
151 		/* no queued read request, use new req structure */
152 		req = raw3215_alloc_req();
153 		req->type = RAW3215_READ;
154 		req->info = raw;
155 		raw->queued_read = req;
156 	}
157 
158 	ccw = req->ccws;
159 	ccw->cmd_code = 0x0A; /* read inquiry */
160 	ccw->flags = 0x20;    /* ignore incorrect length */
161 	ccw->count = 160;
162 	ccw->cda = (__u32) __pa(raw->inbuf);
163 }
164 
165 /*
166  * Set up a write request with the information from the main structure.
167  * A ccw chain is created that writes as much as possible from the output
168  * buffer to the 3215 device. If a queued write exists it is replaced by
169  * the new, probably lengthened request.
170  */
171 static void raw3215_mk_write_req(struct raw3215_info *raw)
172 {
173 	struct raw3215_req *req;
174 	struct ccw1 *ccw;
175 	int len, count, ix, lines;
176 
177 	if (raw->count <= raw->written)
178 		return;
179 	/* check if there is a queued write request */
180 	req = raw->queued_write;
181 	if (req == NULL) {
182 		/* no queued write request, use new req structure */
183 		req = raw3215_alloc_req();
184 		req->type = RAW3215_WRITE;
185 		req->info = raw;
186 		raw->queued_write = req;
187 	} else {
188 		raw->written -= req->len;
189 	}
190 
191 	ccw = req->ccws;
192 	req->start = (raw->head - raw->count + raw->written) &
193 		     (RAW3215_BUFFER_SIZE - 1);
194 	/*
195 	 * now we have to count newlines. We can at max accept
196 	 * RAW3215_MAX_NEWLINE newlines in a single ssch due to
197 	 * a restriction in VM
198 	 */
199 	lines = 0;
200 	ix = req->start;
201 	while (lines < RAW3215_MAX_NEWLINE && ix != raw->head) {
202 		if (raw->buffer[ix] == 0x15)
203 			lines++;
204 		ix = (ix + 1) & (RAW3215_BUFFER_SIZE - 1);
205 	}
206 	len = ((ix - 1 - req->start) & (RAW3215_BUFFER_SIZE - 1)) + 1;
207 	if (len > RAW3215_MAX_BYTES)
208 		len = RAW3215_MAX_BYTES;
209 	req->len = len;
210 	raw->written += len;
211 
212 	/* set the indication if we should try to enlarge this request */
213 	req->delayable = (ix == raw->head) && (len < RAW3215_MIN_WRITE);
214 
215 	ix = req->start;
216 	while (len > 0) {
217 		if (ccw > req->ccws)
218 			ccw[-1].flags |= 0x40; /* use command chaining */
219 		ccw->cmd_code = 0x01; /* write, auto carrier return */
220 		ccw->flags = 0x20;    /* ignore incorrect length ind.  */
221 		ccw->cda =
222 			(__u32) __pa(raw->buffer + ix);
223 		count = len;
224 		if (ix + count > RAW3215_BUFFER_SIZE)
225 			count = RAW3215_BUFFER_SIZE - ix;
226 		ccw->count = count;
227 		len -= count;
228 		ix = (ix + count) & (RAW3215_BUFFER_SIZE - 1);
229 		ccw++;
230 	}
231 	/*
232 	 * Add a NOP to the channel program. 3215 devices are purely
233 	 * emulated and its much better to avoid the channel end
234 	 * interrupt in this case.
235 	 */
236 	if (ccw > req->ccws)
237 		ccw[-1].flags |= 0x40; /* use command chaining */
238 	ccw->cmd_code = 0x03; /* NOP */
239 	ccw->flags = 0;
240 	ccw->cda = 0;
241 	ccw->count = 1;
242 }
243 
244 /*
245  * Start a read or a write request
246  */
247 static void raw3215_start_io(struct raw3215_info *raw)
248 {
249 	struct raw3215_req *req;
250 	int res;
251 
252 	req = raw->queued_read;
253 	if (req != NULL &&
254 	    !(raw->flags & (RAW3215_WORKING | RAW3215_THROTTLED))) {
255 		/* dequeue request */
256 		raw->queued_read = NULL;
257 		res = ccw_device_start(raw->cdev, req->ccws,
258 				       (unsigned long) req, 0, 0);
259 		if (res != 0) {
260 			/* do_IO failed, put request back to queue */
261 			raw->queued_read = req;
262 		} else {
263 			raw->flags |= RAW3215_WORKING;
264 		}
265 	}
266 	req = raw->queued_write;
267 	if (req != NULL &&
268 	    !(raw->flags & (RAW3215_WORKING | RAW3215_STOPPED))) {
269 		/* dequeue request */
270 		raw->queued_write = NULL;
271 		res = ccw_device_start(raw->cdev, req->ccws,
272 				       (unsigned long) req, 0, 0);
273 		if (res != 0) {
274 			/* do_IO failed, put request back to queue */
275 			raw->queued_write = req;
276 		} else {
277 			raw->flags |= RAW3215_WORKING;
278 		}
279 	}
280 }
281 
282 /*
283  * Function to start a delayed output after RAW3215_TIMEOUT seconds
284  */
285 static void raw3215_timeout(struct timer_list *t)
286 {
287 	struct raw3215_info *raw = from_timer(raw, t, timer);
288 	unsigned long flags;
289 
290 	spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
291 	raw->flags &= ~RAW3215_TIMER_RUNS;
292 	raw3215_mk_write_req(raw);
293 	raw3215_start_io(raw);
294 	if ((raw->queued_read || raw->queued_write) &&
295 	    !(raw->flags & RAW3215_WORKING) &&
296 	    !(raw->flags & RAW3215_TIMER_RUNS)) {
297 		raw->timer.expires = RAW3215_TIMEOUT + jiffies;
298 		add_timer(&raw->timer);
299 		raw->flags |= RAW3215_TIMER_RUNS;
300 	}
301 	spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
302 }
303 
304 /*
305  * Function to conditionally start an IO. A read is started immediately,
306  * a write is only started immediately if the flush flag is on or the
307  * amount of data is bigger than RAW3215_MIN_WRITE. If a write is not
308  * done immediately a timer is started with a delay of RAW3215_TIMEOUT.
309  */
310 static inline void raw3215_try_io(struct raw3215_info *raw)
311 {
312 	if (!tty_port_initialized(&raw->port))
313 		return;
314 	if (raw->queued_read != NULL)
315 		raw3215_start_io(raw);
316 	else if (raw->queued_write != NULL) {
317 		if ((raw->queued_write->delayable == 0) ||
318 		    (raw->flags & RAW3215_FLUSHING)) {
319 			/* execute write requests bigger than minimum size */
320 			raw3215_start_io(raw);
321 		}
322 	}
323 	if ((raw->queued_read || raw->queued_write) &&
324 	    !(raw->flags & RAW3215_WORKING) &&
325 	    !(raw->flags & RAW3215_TIMER_RUNS)) {
326 		raw->timer.expires = RAW3215_TIMEOUT + jiffies;
327 		add_timer(&raw->timer);
328 		raw->flags |= RAW3215_TIMER_RUNS;
329 	}
330 }
331 
332 /*
333  * Try to start the next IO and wake up processes waiting on the tty.
334  */
335 static void raw3215_next_io(struct raw3215_info *raw, struct tty_struct *tty)
336 {
337 	raw3215_mk_write_req(raw);
338 	raw3215_try_io(raw);
339 	if (tty && RAW3215_BUFFER_SIZE - raw->count >= RAW3215_MIN_SPACE)
340 		tty_wakeup(tty);
341 }
342 
343 /*
344  * Interrupt routine, called from common io layer
345  */
346 static void raw3215_irq(struct ccw_device *cdev, unsigned long intparm,
347 			struct irb *irb)
348 {
349 	struct raw3215_info *raw;
350 	struct raw3215_req *req;
351 	struct tty_struct *tty;
352 	int cstat, dstat;
353 	int count;
354 
355 	raw = dev_get_drvdata(&cdev->dev);
356 	req = (struct raw3215_req *) intparm;
357 	tty = tty_port_tty_get(&raw->port);
358 	cstat = irb->scsw.cmd.cstat;
359 	dstat = irb->scsw.cmd.dstat;
360 	if (cstat != 0)
361 		raw3215_next_io(raw, tty);
362 	if (dstat & 0x01) { /* we got a unit exception */
363 		dstat &= ~0x01;	 /* we can ignore it */
364 	}
365 	switch (dstat) {
366 	case 0x80:
367 		if (cstat != 0)
368 			break;
369 		/* Attention interrupt, someone hit the enter key */
370 		raw3215_mk_read_req(raw);
371 		raw3215_next_io(raw, tty);
372 		break;
373 	case 0x08:
374 	case 0x0C:
375 		/* Channel end interrupt. */
376 		if ((raw = req->info) == NULL)
377 			goto put_tty;	     /* That shouldn't happen ... */
378 		if (req->type == RAW3215_READ) {
379 			/* store residual count, then wait for device end */
380 			req->residual = irb->scsw.cmd.count;
381 		}
382 		if (dstat == 0x08)
383 			break;
384 		fallthrough;
385 	case 0x04:
386 		/* Device end interrupt. */
387 		if ((raw = req->info) == NULL)
388 			goto put_tty;	     /* That shouldn't happen ... */
389 		if (req->type == RAW3215_READ && tty != NULL) {
390 			unsigned int cchar;
391 
392 			count = 160 - req->residual;
393 			EBCASC(raw->inbuf, count);
394 			cchar = ctrlchar_handle(raw->inbuf, count, tty);
395 			switch (cchar & CTRLCHAR_MASK) {
396 			case CTRLCHAR_SYSRQ:
397 				break;
398 
399 			case CTRLCHAR_CTRL:
400 				tty_insert_flip_char(&raw->port, cchar,
401 						TTY_NORMAL);
402 				tty_flip_buffer_push(&raw->port);
403 				break;
404 
405 			case CTRLCHAR_NONE:
406 				if (count < 2 ||
407 				    (strncmp(raw->inbuf+count-2, "\252n", 2) &&
408 				     strncmp(raw->inbuf+count-2, "^n", 2)) ) {
409 					/* add the auto \n */
410 					raw->inbuf[count] = '\n';
411 					count++;
412 				} else
413 					count -= 2;
414 				tty_insert_flip_string(&raw->port, raw->inbuf,
415 						count);
416 				tty_flip_buffer_push(&raw->port);
417 				break;
418 			}
419 		} else if (req->type == RAW3215_WRITE) {
420 			raw->count -= req->len;
421 			raw->written -= req->len;
422 		}
423 		raw->flags &= ~RAW3215_WORKING;
424 		raw3215_free_req(req);
425 		/* check for empty wait */
426 		if (waitqueue_active(&raw->empty_wait) &&
427 		    raw->queued_write == NULL &&
428 		    raw->queued_read == NULL) {
429 			wake_up_interruptible(&raw->empty_wait);
430 		}
431 		raw3215_next_io(raw, tty);
432 		break;
433 	default:
434 		/* Strange interrupt, I'll do my best to clean up */
435 		if (req != NULL && req->type != RAW3215_FREE) {
436 			if (req->type == RAW3215_WRITE) {
437 				raw->count -= req->len;
438 				raw->written -= req->len;
439 			}
440 			raw->flags &= ~RAW3215_WORKING;
441 			raw3215_free_req(req);
442 		}
443 		raw3215_next_io(raw, tty);
444 	}
445 put_tty:
446 	tty_kref_put(tty);
447 }
448 
449 /*
450  * Wait until length bytes are available int the output buffer.
451  * Has to be called with the s390irq lock held. Can be called
452  * disabled.
453  */
454 static void raw3215_make_room(struct raw3215_info *raw, unsigned int length)
455 {
456 	while (RAW3215_BUFFER_SIZE - raw->count < length) {
457 		/* there might be a request pending */
458 		raw->flags |= RAW3215_FLUSHING;
459 		raw3215_mk_write_req(raw);
460 		raw3215_try_io(raw);
461 		raw->flags &= ~RAW3215_FLUSHING;
462 #ifdef CONFIG_TN3215_CONSOLE
463 		ccw_device_wait_idle(raw->cdev);
464 #endif
465 		/* Enough room freed up ? */
466 		if (RAW3215_BUFFER_SIZE - raw->count >= length)
467 			break;
468 		/* there might be another cpu waiting for the lock */
469 		spin_unlock(get_ccwdev_lock(raw->cdev));
470 		udelay(100);
471 		spin_lock(get_ccwdev_lock(raw->cdev));
472 	}
473 }
474 
475 /*
476  * String write routine for 3215 devices
477  */
478 static void raw3215_write(struct raw3215_info *raw, const char *str,
479 			  unsigned int length)
480 {
481 	unsigned long flags;
482 	int c, count;
483 
484 	while (length > 0) {
485 		spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
486 		count = (length > RAW3215_BUFFER_SIZE) ?
487 					     RAW3215_BUFFER_SIZE : length;
488 		length -= count;
489 
490 		raw3215_make_room(raw, count);
491 
492 		/* copy string to output buffer and convert it to EBCDIC */
493 		while (1) {
494 			c = min_t(int, count,
495 				  min(RAW3215_BUFFER_SIZE - raw->count,
496 				      RAW3215_BUFFER_SIZE - raw->head));
497 			if (c <= 0)
498 				break;
499 			memcpy(raw->buffer + raw->head, str, c);
500 			ASCEBC(raw->buffer + raw->head, c);
501 			raw->head = (raw->head + c) & (RAW3215_BUFFER_SIZE - 1);
502 			raw->count += c;
503 			raw->line_pos += c;
504 			str += c;
505 			count -= c;
506 		}
507 		if (!(raw->flags & RAW3215_WORKING)) {
508 			raw3215_mk_write_req(raw);
509 			/* start or queue request */
510 			raw3215_try_io(raw);
511 		}
512 		spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
513 	}
514 }
515 
516 /*
517  * Put character routine for 3215 devices
518  */
519 static void raw3215_putchar(struct raw3215_info *raw, unsigned char ch)
520 {
521 	unsigned long flags;
522 	unsigned int length, i;
523 
524 	spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
525 	if (ch == '\t') {
526 		length = TAB_STOP_SIZE - (raw->line_pos%TAB_STOP_SIZE);
527 		raw->line_pos += length;
528 		ch = ' ';
529 	} else if (ch == '\n') {
530 		length = 1;
531 		raw->line_pos = 0;
532 	} else {
533 		length = 1;
534 		raw->line_pos++;
535 	}
536 	raw3215_make_room(raw, length);
537 
538 	for (i = 0; i < length; i++) {
539 		raw->buffer[raw->head] = (char) _ascebc[(int) ch];
540 		raw->head = (raw->head + 1) & (RAW3215_BUFFER_SIZE - 1);
541 		raw->count++;
542 	}
543 	if (!(raw->flags & RAW3215_WORKING)) {
544 		raw3215_mk_write_req(raw);
545 		/* start or queue request */
546 		raw3215_try_io(raw);
547 	}
548 	spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
549 }
550 
551 /*
552  * Flush routine, it simply sets the flush flag and tries to start
553  * pending IO.
554  */
555 static void raw3215_flush_buffer(struct raw3215_info *raw)
556 {
557 	unsigned long flags;
558 
559 	spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
560 	if (raw->count > 0) {
561 		raw->flags |= RAW3215_FLUSHING;
562 		raw3215_try_io(raw);
563 		raw->flags &= ~RAW3215_FLUSHING;
564 	}
565 	spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
566 }
567 
568 /*
569  * Fire up a 3215 device.
570  */
571 static int raw3215_startup(struct raw3215_info *raw)
572 {
573 	unsigned long flags;
574 
575 	if (tty_port_initialized(&raw->port))
576 		return 0;
577 	raw->line_pos = 0;
578 	tty_port_set_initialized(&raw->port, 1);
579 	spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
580 	raw3215_try_io(raw);
581 	spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
582 
583 	return 0;
584 }
585 
586 /*
587  * Shutdown a 3215 device.
588  */
589 static void raw3215_shutdown(struct raw3215_info *raw)
590 {
591 	DECLARE_WAITQUEUE(wait, current);
592 	unsigned long flags;
593 
594 	if (!tty_port_initialized(&raw->port) || (raw->flags & RAW3215_FIXED))
595 		return;
596 	/* Wait for outstanding requests, then free irq */
597 	spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
598 	if ((raw->flags & RAW3215_WORKING) ||
599 	    raw->queued_write != NULL ||
600 	    raw->queued_read != NULL) {
601 		add_wait_queue(&raw->empty_wait, &wait);
602 		set_current_state(TASK_INTERRUPTIBLE);
603 		spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
604 		schedule();
605 		spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
606 		remove_wait_queue(&raw->empty_wait, &wait);
607 		set_current_state(TASK_RUNNING);
608 		tty_port_set_initialized(&raw->port, 1);
609 	}
610 	spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
611 }
612 
613 static struct raw3215_info *raw3215_alloc_info(void)
614 {
615 	struct raw3215_info *info;
616 
617 	info = kzalloc(sizeof(struct raw3215_info), GFP_KERNEL | GFP_DMA);
618 	if (!info)
619 		return NULL;
620 
621 	info->buffer = kzalloc(RAW3215_BUFFER_SIZE, GFP_KERNEL | GFP_DMA);
622 	info->inbuf = kzalloc(RAW3215_INBUF_SIZE, GFP_KERNEL | GFP_DMA);
623 	if (!info->buffer || !info->inbuf) {
624 		kfree(info->inbuf);
625 		kfree(info->buffer);
626 		kfree(info);
627 		return NULL;
628 	}
629 
630 	timer_setup(&info->timer, raw3215_timeout, 0);
631 	init_waitqueue_head(&info->empty_wait);
632 	tty_port_init(&info->port);
633 
634 	return info;
635 }
636 
637 static void raw3215_free_info(struct raw3215_info *raw)
638 {
639 	kfree(raw->inbuf);
640 	kfree(raw->buffer);
641 	tty_port_destroy(&raw->port);
642 	kfree(raw);
643 }
644 
645 static int raw3215_probe (struct ccw_device *cdev)
646 {
647 	struct raw3215_info *raw;
648 	int line;
649 
650 	/* Console is special. */
651 	if (raw3215[0] && (raw3215[0] == dev_get_drvdata(&cdev->dev)))
652 		return 0;
653 
654 	raw = raw3215_alloc_info();
655 	if (raw == NULL)
656 		return -ENOMEM;
657 
658 	raw->cdev = cdev;
659 	dev_set_drvdata(&cdev->dev, raw);
660 	cdev->handler = raw3215_irq;
661 
662 	spin_lock(&raw3215_device_lock);
663 	for (line = 0; line < NR_3215; line++) {
664 		if (!raw3215[line]) {
665 			raw3215[line] = raw;
666 			break;
667 		}
668 	}
669 	spin_unlock(&raw3215_device_lock);
670 	if (line == NR_3215) {
671 		raw3215_free_info(raw);
672 		return -ENODEV;
673 	}
674 
675 	return 0;
676 }
677 
678 static void raw3215_remove (struct ccw_device *cdev)
679 {
680 	struct raw3215_info *raw;
681 	unsigned int line;
682 
683 	ccw_device_set_offline(cdev);
684 	raw = dev_get_drvdata(&cdev->dev);
685 	if (raw) {
686 		spin_lock(&raw3215_device_lock);
687 		for (line = 0; line < NR_3215; line++)
688 			if (raw3215[line] == raw)
689 				break;
690 		raw3215[line] = NULL;
691 		spin_unlock(&raw3215_device_lock);
692 		dev_set_drvdata(&cdev->dev, NULL);
693 		raw3215_free_info(raw);
694 	}
695 }
696 
697 static int raw3215_set_online (struct ccw_device *cdev)
698 {
699 	struct raw3215_info *raw;
700 
701 	raw = dev_get_drvdata(&cdev->dev);
702 	if (!raw)
703 		return -ENODEV;
704 
705 	return raw3215_startup(raw);
706 }
707 
708 static int raw3215_set_offline (struct ccw_device *cdev)
709 {
710 	struct raw3215_info *raw;
711 
712 	raw = dev_get_drvdata(&cdev->dev);
713 	if (!raw)
714 		return -ENODEV;
715 
716 	raw3215_shutdown(raw);
717 
718 	return 0;
719 }
720 
721 static struct ccw_device_id raw3215_id[] = {
722 	{ CCW_DEVICE(0x3215, 0) },
723 	{ /* end of list */ },
724 };
725 
726 static struct ccw_driver raw3215_ccw_driver = {
727 	.driver = {
728 		.name	= "3215",
729 		.owner	= THIS_MODULE,
730 	},
731 	.ids		= raw3215_id,
732 	.probe		= &raw3215_probe,
733 	.remove		= &raw3215_remove,
734 	.set_online	= &raw3215_set_online,
735 	.set_offline	= &raw3215_set_offline,
736 	.int_class	= IRQIO_C15,
737 };
738 
739 #ifdef CONFIG_TN3215_CONSOLE
740 /*
741  * Write a string to the 3215 console
742  */
743 static void con3215_write(struct console *co, const char *str,
744 			  unsigned int count)
745 {
746 	struct raw3215_info *raw;
747 	int i;
748 
749 	if (count <= 0)
750 		return;
751 	raw = raw3215[0];	/* console 3215 is the first one */
752 	while (count > 0) {
753 		for (i = 0; i < count; i++)
754 			if (str[i] == '\t' || str[i] == '\n')
755 				break;
756 		raw3215_write(raw, str, i);
757 		count -= i;
758 		str += i;
759 		if (count > 0) {
760 			raw3215_putchar(raw, *str);
761 			count--;
762 			str++;
763 		}
764 	}
765 }
766 
767 static struct tty_driver *con3215_device(struct console *c, int *index)
768 {
769 	*index = c->index;
770 	return tty3215_driver;
771 }
772 
773 /*
774  * The below function is called as a panic/reboot notifier before the
775  * system enters a disabled, endless loop.
776  *
777  * Notice we must use the spin_trylock() alternative, to prevent lockups
778  * in atomic context (panic routine runs with secondary CPUs, local IRQs
779  * and preemption disabled).
780  */
781 static int con3215_notify(struct notifier_block *self,
782 			  unsigned long event, void *data)
783 {
784 	struct raw3215_info *raw;
785 	unsigned long flags;
786 
787 	raw = raw3215[0];  /* console 3215 is the first one */
788 	if (!spin_trylock_irqsave(get_ccwdev_lock(raw->cdev), flags))
789 		return NOTIFY_DONE;
790 	raw3215_make_room(raw, RAW3215_BUFFER_SIZE);
791 	spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
792 
793 	return NOTIFY_DONE;
794 }
795 
796 static struct notifier_block on_panic_nb = {
797 	.notifier_call = con3215_notify,
798 	.priority = INT_MIN + 1, /* run the callback late */
799 };
800 
801 static struct notifier_block on_reboot_nb = {
802 	.notifier_call = con3215_notify,
803 	.priority = INT_MIN + 1, /* run the callback late */
804 };
805 
806 /*
807  *  The console structure for the 3215 console
808  */
809 static struct console con3215 = {
810 	.name	 = "ttyS",
811 	.write	 = con3215_write,
812 	.device	 = con3215_device,
813 	.flags	 = CON_PRINTBUFFER,
814 };
815 
816 /*
817  * 3215 console initialization code called from console_init().
818  */
819 static int __init con3215_init(void)
820 {
821 	struct ccw_device *cdev;
822 	struct raw3215_info *raw;
823 	struct raw3215_req *req;
824 	int i;
825 
826 	/* Check if 3215 is to be the console */
827 	if (!CONSOLE_IS_3215)
828 		return -ENODEV;
829 
830 	/* Set the console mode for VM */
831 	if (MACHINE_IS_VM) {
832 		cpcmd("TERM CONMODE 3215", NULL, 0, NULL);
833 		cpcmd("TERM AUTOCR OFF", NULL, 0, NULL);
834 	}
835 
836 	/* allocate 3215 request structures */
837 	raw3215_freelist = NULL;
838 	for (i = 0; i < NR_3215_REQ; i++) {
839 		req = kzalloc(sizeof(struct raw3215_req), GFP_KERNEL | GFP_DMA);
840 		if (!req)
841 			return -ENOMEM;
842 		req->next = raw3215_freelist;
843 		raw3215_freelist = req;
844 	}
845 
846 	cdev = ccw_device_create_console(&raw3215_ccw_driver);
847 	if (IS_ERR(cdev))
848 		return -ENODEV;
849 
850 	raw3215[0] = raw = raw3215_alloc_info();
851 	raw->cdev = cdev;
852 	dev_set_drvdata(&cdev->dev, raw);
853 	cdev->handler = raw3215_irq;
854 
855 	raw->flags |= RAW3215_FIXED;
856 	if (ccw_device_enable_console(cdev)) {
857 		ccw_device_destroy_console(cdev);
858 		raw3215_free_info(raw);
859 		raw3215[0] = NULL;
860 		return -ENODEV;
861 	}
862 
863 	/* Request the console irq */
864 	if (raw3215_startup(raw) != 0) {
865 		raw3215_free_info(raw);
866 		raw3215[0] = NULL;
867 		return -ENODEV;
868 	}
869 	atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
870 	register_reboot_notifier(&on_reboot_nb);
871 	register_console(&con3215);
872 	return 0;
873 }
874 console_initcall(con3215_init);
875 #endif
876 
877 static int tty3215_install(struct tty_driver *driver, struct tty_struct *tty)
878 {
879 	struct raw3215_info *raw;
880 
881 	raw = raw3215[tty->index];
882 	if (raw == NULL)
883 		return -ENODEV;
884 
885 	tty->driver_data = raw;
886 
887 	return tty_port_install(&raw->port, driver, tty);
888 }
889 
890 /*
891  * tty3215_open
892  *
893  * This routine is called whenever a 3215 tty is opened.
894  */
895 static int tty3215_open(struct tty_struct *tty, struct file * filp)
896 {
897 	struct raw3215_info *raw = tty->driver_data;
898 
899 	tty_port_tty_set(&raw->port, tty);
900 
901 	/*
902 	 * Start up 3215 device
903 	 */
904 	return raw3215_startup(raw);
905 }
906 
907 /*
908  * tty3215_close()
909  *
910  * This routine is called when the 3215 tty is closed. We wait
911  * for the remaining request to be completed. Then we clean up.
912  */
913 static void tty3215_close(struct tty_struct *tty, struct file * filp)
914 {
915 	struct raw3215_info *raw = tty->driver_data;
916 
917 	if (raw == NULL || tty->count > 1)
918 		return;
919 	tty->closing = 1;
920 	/* Shutdown the terminal */
921 	raw3215_shutdown(raw);
922 	tty->closing = 0;
923 	tty_port_tty_set(&raw->port, NULL);
924 }
925 
926 /*
927  * Returns the amount of free space in the output buffer.
928  */
929 static unsigned int tty3215_write_room(struct tty_struct *tty)
930 {
931 	struct raw3215_info *raw = tty->driver_data;
932 
933 	/* Subtract TAB_STOP_SIZE to allow for a tab, 8 <<< 64K */
934 	if ((RAW3215_BUFFER_SIZE - raw->count - TAB_STOP_SIZE) >= 0)
935 		return RAW3215_BUFFER_SIZE - raw->count - TAB_STOP_SIZE;
936 	else
937 		return 0;
938 }
939 
940 /*
941  * String write routine for 3215 ttys
942  */
943 static int tty3215_write(struct tty_struct * tty,
944 			 const unsigned char *buf, int count)
945 {
946 	struct raw3215_info *raw = tty->driver_data;
947 	int i, written;
948 
949 	written = count;
950 	while (count > 0) {
951 		for (i = 0; i < count; i++)
952 			if (buf[i] == '\t' || buf[i] == '\n')
953 				break;
954 		raw3215_write(raw, buf, i);
955 		count -= i;
956 		buf += i;
957 		if (count > 0) {
958 			raw3215_putchar(raw, *buf);
959 			count--;
960 			buf++;
961 		}
962 	}
963 	return written;
964 }
965 
966 /*
967  * Put character routine for 3215 ttys
968  */
969 static int tty3215_put_char(struct tty_struct *tty, unsigned char ch)
970 {
971 	struct raw3215_info *raw = tty->driver_data;
972 
973 	raw3215_putchar(raw, ch);
974 
975 	return 1;
976 }
977 
978 static void tty3215_flush_chars(struct tty_struct *tty)
979 {
980 }
981 
982 /*
983  * Returns the number of characters in the output buffer
984  */
985 static unsigned int tty3215_chars_in_buffer(struct tty_struct *tty)
986 {
987 	struct raw3215_info *raw = tty->driver_data;
988 
989 	return raw->count;
990 }
991 
992 static void tty3215_flush_buffer(struct tty_struct *tty)
993 {
994 	struct raw3215_info *raw = tty->driver_data;
995 
996 	raw3215_flush_buffer(raw);
997 	tty_wakeup(tty);
998 }
999 
1000 /*
1001  * Disable reading from a 3215 tty
1002  */
1003 static void tty3215_throttle(struct tty_struct * tty)
1004 {
1005 	struct raw3215_info *raw = tty->driver_data;
1006 
1007 	raw->flags |= RAW3215_THROTTLED;
1008 }
1009 
1010 /*
1011  * Enable reading from a 3215 tty
1012  */
1013 static void tty3215_unthrottle(struct tty_struct * tty)
1014 {
1015 	struct raw3215_info *raw = tty->driver_data;
1016 	unsigned long flags;
1017 
1018 	if (raw->flags & RAW3215_THROTTLED) {
1019 		spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
1020 		raw->flags &= ~RAW3215_THROTTLED;
1021 		raw3215_try_io(raw);
1022 		spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
1023 	}
1024 }
1025 
1026 /*
1027  * Disable writing to a 3215 tty
1028  */
1029 static void tty3215_stop(struct tty_struct *tty)
1030 {
1031 	struct raw3215_info *raw = tty->driver_data;
1032 
1033 	raw->flags |= RAW3215_STOPPED;
1034 }
1035 
1036 /*
1037  * Enable writing to a 3215 tty
1038  */
1039 static void tty3215_start(struct tty_struct *tty)
1040 {
1041 	struct raw3215_info *raw = tty->driver_data;
1042 	unsigned long flags;
1043 
1044 	if (raw->flags & RAW3215_STOPPED) {
1045 		spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
1046 		raw->flags &= ~RAW3215_STOPPED;
1047 		raw3215_try_io(raw);
1048 		spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
1049 	}
1050 }
1051 
1052 static const struct tty_operations tty3215_ops = {
1053 	.install = tty3215_install,
1054 	.open = tty3215_open,
1055 	.close = tty3215_close,
1056 	.write = tty3215_write,
1057 	.put_char = tty3215_put_char,
1058 	.flush_chars = tty3215_flush_chars,
1059 	.write_room = tty3215_write_room,
1060 	.chars_in_buffer = tty3215_chars_in_buffer,
1061 	.flush_buffer = tty3215_flush_buffer,
1062 	.throttle = tty3215_throttle,
1063 	.unthrottle = tty3215_unthrottle,
1064 	.stop = tty3215_stop,
1065 	.start = tty3215_start,
1066 };
1067 
1068 /*
1069  * 3215 tty registration code called from tty_init().
1070  * Most kernel services (incl. kmalloc) are available at this poimt.
1071  */
1072 static int __init tty3215_init(void)
1073 {
1074 	struct tty_driver *driver;
1075 	int ret;
1076 
1077 	if (!CONSOLE_IS_3215)
1078 		return 0;
1079 
1080 	driver = tty_alloc_driver(NR_3215, TTY_DRIVER_REAL_RAW);
1081 	if (IS_ERR(driver))
1082 		return PTR_ERR(driver);
1083 
1084 	ret = ccw_driver_register(&raw3215_ccw_driver);
1085 	if (ret) {
1086 		tty_driver_kref_put(driver);
1087 		return ret;
1088 	}
1089 	/*
1090 	 * Initialize the tty_driver structure
1091 	 * Entries in tty3215_driver that are NOT initialized:
1092 	 * proc_entry, set_termios, flush_buffer, set_ldisc, write_proc
1093 	 */
1094 
1095 	driver->driver_name = "tty3215";
1096 	driver->name = "ttyS";
1097 	driver->major = TTY_MAJOR;
1098 	driver->minor_start = 64;
1099 	driver->type = TTY_DRIVER_TYPE_SYSTEM;
1100 	driver->subtype = SYSTEM_TYPE_TTY;
1101 	driver->init_termios = tty_std_termios;
1102 	driver->init_termios.c_iflag = IGNBRK | IGNPAR;
1103 	driver->init_termios.c_oflag = ONLCR;
1104 	driver->init_termios.c_lflag = ISIG;
1105 	tty_set_operations(driver, &tty3215_ops);
1106 	ret = tty_register_driver(driver);
1107 	if (ret) {
1108 		tty_driver_kref_put(driver);
1109 		return ret;
1110 	}
1111 	tty3215_driver = driver;
1112 	return 0;
1113 }
1114 device_initcall(tty3215_init);
1115