2 * drivers/s390/char/sclp_vt220.c
3 * SCLP VT220 terminal driver.
6 * Copyright IBM Corp. 2003,2008
7 * Author(s): Peter Oberparleiter <Peter.Oberparleiter@de.ibm.com>
10 #include <linux/module.h>
11 #include <linux/spinlock.h>
12 #include <linux/list.h>
13 #include <linux/wait.h>
14 #include <linux/timer.h>
15 #include <linux/kernel.h>
16 #include <linux/tty.h>
17 #include <linux/tty_driver.h>
18 #include <linux/tty_flip.h>
19 #include <linux/errno.h>
21 #include <linux/major.h>
22 #include <linux/console.h>
23 #include <linux/kdev_t.h>
24 #include <linux/bootmem.h>
25 #include <linux/interrupt.h>
26 #include <linux/init.h>
27 #include <asm/uaccess.h>
30 #define SCLP_VT220_PRINT_HEADER "sclp vt220 tty driver: "
31 #define SCLP_VT220_MAJOR TTY_MAJOR
32 #define SCLP_VT220_MINOR 65
33 #define SCLP_VT220_DRIVER_NAME "sclp_vt220"
34 #define SCLP_VT220_DEVICE_NAME "ttysclp"
35 #define SCLP_VT220_CONSOLE_NAME "ttyS"
36 #define SCLP_VT220_CONSOLE_INDEX 1 /* console=ttyS1 */
37 #define SCLP_VT220_BUF_SIZE 80
39 /* Representation of a single write request */
40 struct sclp_vt220_request {
41 struct list_head list;
42 struct sclp_req sclp_req;
47 struct sclp_vt220_sccb {
48 struct sccb_header header;
49 struct evbuf_header evbuf;
52 #define SCLP_VT220_MAX_CHARS_PER_BUFFER (PAGE_SIZE - \
53 sizeof(struct sclp_vt220_request) - \
54 sizeof(struct sclp_vt220_sccb))
56 /* Structures and data needed to register tty driver */
57 static struct tty_driver *sclp_vt220_driver;
59 /* The tty_struct that the kernel associated with us */
60 static struct tty_struct *sclp_vt220_tty;
62 /* Lock to protect internal data from concurrent access */
63 static spinlock_t sclp_vt220_lock;
65 /* List of empty pages to be used as write request buffers */
66 static struct list_head sclp_vt220_empty;
68 /* List of pending requests */
69 static struct list_head sclp_vt220_outqueue;
71 /* Number of requests in outqueue */
72 static int sclp_vt220_outqueue_count;
74 /* Timer used for delaying write requests to merge subsequent messages into
76 static struct timer_list sclp_vt220_timer;
78 /* Pointer to current request buffer which has been partially filled but not
80 static struct sclp_vt220_request *sclp_vt220_current_request;
82 /* Number of characters in current request buffer */
83 static int sclp_vt220_buffered_chars;
85 /* Flag indicating whether this driver has already been initialized */
86 static int sclp_vt220_initialized = 0;
88 /* Flag indicating that sclp_vt220_current_request should really
89 * have been already queued but wasn't because the SCLP was processing
91 static int sclp_vt220_flush_later;
93 static void sclp_vt220_receiver_fn(struct evbuf_header *evbuf);
94 static int __sclp_vt220_emit(struct sclp_vt220_request *request);
95 static void sclp_vt220_emit_current(void);
97 /* Registration structure for our interest in SCLP event buffers */
98 static struct sclp_register sclp_vt220_register = {
99 .send_mask = EVTYP_VT220MSG_MASK,
100 .receive_mask = EVTYP_VT220MSG_MASK,
101 .state_change_fn = NULL,
102 .receiver_fn = sclp_vt220_receiver_fn
107 * Put provided request buffer back into queue and check emit pending
108 * buffers if necessary.
111 sclp_vt220_process_queue(struct sclp_vt220_request *request)
117 /* Put buffer back to list of empty buffers */
118 page = request->sclp_req.sccb;
119 spin_lock_irqsave(&sclp_vt220_lock, flags);
120 /* Move request from outqueue to empty queue */
121 list_del(&request->list);
122 sclp_vt220_outqueue_count--;
123 list_add_tail((struct list_head *) page, &sclp_vt220_empty);
124 /* Check if there is a pending buffer on the out queue. */
126 if (!list_empty(&sclp_vt220_outqueue))
127 request = list_entry(sclp_vt220_outqueue.next,
128 struct sclp_vt220_request, list);
129 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
130 } while (request && __sclp_vt220_emit(request));
131 if (request == NULL && sclp_vt220_flush_later)
132 sclp_vt220_emit_current();
133 /* Check if the tty needs a wake up call */
134 if (sclp_vt220_tty != NULL) {
135 tty_wakeup(sclp_vt220_tty);
139 #define SCLP_BUFFER_MAX_RETRY 1
142 * Callback through which the result of a write request is reported by the
146 sclp_vt220_callback(struct sclp_req *request, void *data)
148 struct sclp_vt220_request *vt220_request;
149 struct sclp_vt220_sccb *sccb;
151 vt220_request = (struct sclp_vt220_request *) data;
152 if (request->status == SCLP_REQ_FAILED) {
153 sclp_vt220_process_queue(vt220_request);
156 sccb = (struct sclp_vt220_sccb *) vt220_request->sclp_req.sccb;
158 /* Check SCLP response code and choose suitable action */
159 switch (sccb->header.response_code) {
163 case 0x05f0: /* Target resource in improper state */
166 case 0x0340: /* Contained SCLP equipment check */
167 if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY)
169 /* Remove processed buffers and requeue rest */
170 if (sclp_remove_processed((struct sccb_header *) sccb) > 0) {
171 /* Not all buffers were processed */
172 sccb->header.response_code = 0x0000;
173 vt220_request->sclp_req.status = SCLP_REQ_FILLED;
174 if (sclp_add_request(request) == 0)
179 case 0x0040: /* SCLP equipment check */
180 if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY)
182 sccb->header.response_code = 0x0000;
183 vt220_request->sclp_req.status = SCLP_REQ_FILLED;
184 if (sclp_add_request(request) == 0)
191 sclp_vt220_process_queue(vt220_request);
195 * Emit vt220 request buffer to SCLP. Return zero on success, non-zero
199 __sclp_vt220_emit(struct sclp_vt220_request *request)
201 if (!(sclp_vt220_register.sclp_receive_mask & EVTYP_VT220MSG_MASK)) {
202 request->sclp_req.status = SCLP_REQ_FAILED;
205 request->sclp_req.command = SCLP_CMDW_WRITE_EVENT_DATA;
206 request->sclp_req.status = SCLP_REQ_FILLED;
207 request->sclp_req.callback = sclp_vt220_callback;
208 request->sclp_req.callback_data = (void *) request;
210 return sclp_add_request(&request->sclp_req);
214 * Queue and emit given request.
217 sclp_vt220_emit(struct sclp_vt220_request *request)
222 spin_lock_irqsave(&sclp_vt220_lock, flags);
223 list_add_tail(&request->list, &sclp_vt220_outqueue);
224 count = sclp_vt220_outqueue_count++;
225 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
226 /* Emit only the first buffer immediately - callback takes care of
228 if (count == 0 && __sclp_vt220_emit(request))
229 sclp_vt220_process_queue(request);
233 * Queue and emit current request. Return zero on success, non-zero otherwise.
236 sclp_vt220_emit_current(void)
239 struct sclp_vt220_request *request;
240 struct sclp_vt220_sccb *sccb;
242 spin_lock_irqsave(&sclp_vt220_lock, flags);
244 if (sclp_vt220_current_request != NULL) {
245 sccb = (struct sclp_vt220_sccb *)
246 sclp_vt220_current_request->sclp_req.sccb;
247 /* Only emit buffers with content */
248 if (sccb->header.length != sizeof(struct sclp_vt220_sccb)) {
249 request = sclp_vt220_current_request;
250 sclp_vt220_current_request = NULL;
251 if (timer_pending(&sclp_vt220_timer))
252 del_timer(&sclp_vt220_timer);
254 sclp_vt220_flush_later = 0;
256 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
258 sclp_vt220_emit(request);
261 #define SCLP_NORMAL_WRITE 0x00
264 * Helper function to initialize a page with the sclp request structure.
266 static struct sclp_vt220_request *
267 sclp_vt220_initialize_page(void *page)
269 struct sclp_vt220_request *request;
270 struct sclp_vt220_sccb *sccb;
272 /* Place request structure at end of page */
273 request = ((struct sclp_vt220_request *)
274 ((addr_t) page + PAGE_SIZE)) - 1;
275 request->retry_count = 0;
276 request->sclp_req.sccb = page;
277 /* SCCB goes at start of page */
278 sccb = (struct sclp_vt220_sccb *) page;
279 memset((void *) sccb, 0, sizeof(struct sclp_vt220_sccb));
280 sccb->header.length = sizeof(struct sclp_vt220_sccb);
281 sccb->header.function_code = SCLP_NORMAL_WRITE;
282 sccb->header.response_code = 0x0000;
283 sccb->evbuf.type = EVTYP_VT220MSG;
284 sccb->evbuf.length = sizeof(struct evbuf_header);
289 static inline unsigned int
290 sclp_vt220_space_left(struct sclp_vt220_request *request)
292 struct sclp_vt220_sccb *sccb;
293 sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
294 return PAGE_SIZE - sizeof(struct sclp_vt220_request) -
298 static inline unsigned int
299 sclp_vt220_chars_stored(struct sclp_vt220_request *request)
301 struct sclp_vt220_sccb *sccb;
302 sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
303 return sccb->evbuf.length - sizeof(struct evbuf_header);
307 * Add msg to buffer associated with request. Return the number of characters
311 sclp_vt220_add_msg(struct sclp_vt220_request *request,
312 const unsigned char *msg, int count, int convertlf)
314 struct sclp_vt220_sccb *sccb;
320 if (count > sclp_vt220_space_left(request))
321 count = sclp_vt220_space_left(request);
325 sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
326 buffer = (void *) ((addr_t) sccb + sccb->header.length);
329 /* Perform Linefeed conversion (0x0a -> 0x0a 0x0d)*/
331 (from < count) && (to < sclp_vt220_space_left(request));
333 /* Retrieve character */
335 /* Perform conversion */
337 if (to + 1 < sclp_vt220_space_left(request)) {
338 ((unsigned char *) buffer)[to++] = c;
339 ((unsigned char *) buffer)[to++] = 0x0d;
344 ((unsigned char *) buffer)[to++] = c;
346 sccb->header.length += to;
347 sccb->evbuf.length += to;
350 memcpy(buffer, (const void *) msg, count);
351 sccb->header.length += count;
352 sccb->evbuf.length += count;
358 * Emit buffer after having waited long enough for more data to arrive.
361 sclp_vt220_timeout(unsigned long data)
363 sclp_vt220_emit_current();
366 #define BUFFER_MAX_DELAY HZ/20
369 * Internal implementation of the write function. Write COUNT bytes of data
371 * to the SCLP interface. In case that the data does not fit into the current
372 * write buffer, emit the current one and allocate a new one. If there are no
373 * more empty buffers available, wait until one gets emptied. If DO_SCHEDULE
374 * is non-zero, the buffer will be scheduled for emitting after a timeout -
375 * otherwise the user has to explicitly call the flush function.
376 * A non-zero CONVERTLF parameter indicates that 0x0a characters in the message
377 * buffer should be converted to 0x0a 0x0d. After completion, return the number
381 __sclp_vt220_write(const unsigned char *buf, int count, int do_schedule,
382 int convertlf, int may_fail)
392 spin_lock_irqsave(&sclp_vt220_lock, flags);
394 /* Create an sclp output buffer if none exists yet */
395 if (sclp_vt220_current_request == NULL) {
396 while (list_empty(&sclp_vt220_empty)) {
397 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
402 spin_lock_irqsave(&sclp_vt220_lock, flags);
404 page = (void *) sclp_vt220_empty.next;
405 list_del((struct list_head *) page);
406 sclp_vt220_current_request =
407 sclp_vt220_initialize_page(page);
409 /* Try to write the string to the current request buffer */
410 written = sclp_vt220_add_msg(sclp_vt220_current_request,
411 buf, count, convertlf);
412 overall_written += written;
413 if (written == count)
416 * Not all characters could be written to the current
417 * output buffer. Emit the buffer, create a new buffer
418 * and then output the rest of the string.
420 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
421 sclp_vt220_emit_current();
422 spin_lock_irqsave(&sclp_vt220_lock, flags);
426 /* Setup timer to output current console buffer after some time */
427 if (sclp_vt220_current_request != NULL &&
428 !timer_pending(&sclp_vt220_timer) && do_schedule) {
429 sclp_vt220_timer.function = sclp_vt220_timeout;
430 sclp_vt220_timer.data = 0UL;
431 sclp_vt220_timer.expires = jiffies + BUFFER_MAX_DELAY;
432 add_timer(&sclp_vt220_timer);
434 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
436 return overall_written;
440 * This routine is called by the kernel to write a series of
441 * characters to the tty device. The characters may come from
442 * user space or kernel space. This routine will return the
443 * number of characters actually accepted for writing.
446 sclp_vt220_write(struct tty_struct *tty, const unsigned char *buf, int count)
448 return __sclp_vt220_write(buf, count, 1, 0, 1);
451 #define SCLP_VT220_SESSION_ENDED 0x01
452 #define SCLP_VT220_SESSION_STARTED 0x80
453 #define SCLP_VT220_SESSION_DATA 0x00
456 * Called by the SCLP to report incoming event buffers.
459 sclp_vt220_receiver_fn(struct evbuf_header *evbuf)
464 /* Ignore input if device is not open */
465 if (sclp_vt220_tty == NULL)
468 buffer = (char *) ((addr_t) evbuf + sizeof(struct evbuf_header));
469 count = evbuf->length - sizeof(struct evbuf_header);
472 case SCLP_VT220_SESSION_ENDED:
473 case SCLP_VT220_SESSION_STARTED:
475 case SCLP_VT220_SESSION_DATA:
476 /* Send input to line discipline */
479 tty_insert_flip_string(sclp_vt220_tty, buffer, count);
480 tty_flip_buffer_push(sclp_vt220_tty);
486 * This routine is called when a particular tty device is opened.
489 sclp_vt220_open(struct tty_struct *tty, struct file *filp)
491 if (tty->count == 1) {
492 sclp_vt220_tty = tty;
493 tty->driver_data = kmalloc(SCLP_VT220_BUF_SIZE, GFP_KERNEL);
494 if (tty->driver_data == NULL)
496 tty->low_latency = 0;
502 * This routine is called when a particular tty device is closed.
505 sclp_vt220_close(struct tty_struct *tty, struct file *filp)
507 if (tty->count == 1) {
508 sclp_vt220_tty = NULL;
509 kfree(tty->driver_data);
510 tty->driver_data = NULL;
515 * This routine is called by the kernel to write a single
516 * character to the tty device. If the kernel uses this routine,
517 * it must call the flush_chars() routine (if defined) when it is
518 * done stuffing characters into the driver.
521 sclp_vt220_put_char(struct tty_struct *tty, unsigned char ch)
523 return __sclp_vt220_write(&ch, 1, 0, 0, 1);
527 * This routine is called by the kernel after it has written a
528 * series of characters to the tty device using put_char().
531 sclp_vt220_flush_chars(struct tty_struct *tty)
533 if (sclp_vt220_outqueue_count == 0)
534 sclp_vt220_emit_current();
536 sclp_vt220_flush_later = 1;
540 * This routine returns the numbers of characters the tty driver
541 * will accept for queuing to be written. This number is subject
542 * to change as output buffers get emptied, or if the output flow
546 sclp_vt220_write_room(struct tty_struct *tty)
552 spin_lock_irqsave(&sclp_vt220_lock, flags);
554 if (sclp_vt220_current_request != NULL)
555 count = sclp_vt220_space_left(sclp_vt220_current_request);
556 list_for_each(l, &sclp_vt220_empty)
557 count += SCLP_VT220_MAX_CHARS_PER_BUFFER;
558 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
563 * Return number of buffered chars.
566 sclp_vt220_chars_in_buffer(struct tty_struct *tty)
570 struct sclp_vt220_request *r;
573 spin_lock_irqsave(&sclp_vt220_lock, flags);
575 if (sclp_vt220_current_request != NULL)
576 count = sclp_vt220_chars_stored(sclp_vt220_current_request);
577 list_for_each(l, &sclp_vt220_outqueue) {
578 r = list_entry(l, struct sclp_vt220_request, list);
579 count += sclp_vt220_chars_stored(r);
581 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
586 __sclp_vt220_flush_buffer(void)
590 sclp_vt220_emit_current();
591 spin_lock_irqsave(&sclp_vt220_lock, flags);
592 if (timer_pending(&sclp_vt220_timer))
593 del_timer(&sclp_vt220_timer);
594 while (sclp_vt220_outqueue_count > 0) {
595 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
597 spin_lock_irqsave(&sclp_vt220_lock, flags);
599 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
603 * Pass on all buffers to the hardware. Return only when there are no more
607 sclp_vt220_flush_buffer(struct tty_struct *tty)
609 sclp_vt220_emit_current();
613 * Initialize all relevant components and register driver with system.
615 static void __init __sclp_vt220_cleanup(void)
617 struct list_head *page, *p;
619 list_for_each_safe(page, p, &sclp_vt220_empty) {
621 if (slab_is_available())
622 free_page((unsigned long) page);
624 free_bootmem((unsigned long) page, PAGE_SIZE);
626 if (!list_empty(&sclp_vt220_register.list))
627 sclp_unregister(&sclp_vt220_register);
628 sclp_vt220_initialized = 0;
631 static int __init __sclp_vt220_init(void)
638 if (sclp_vt220_initialized)
640 sclp_vt220_initialized = 1;
641 spin_lock_init(&sclp_vt220_lock);
642 INIT_LIST_HEAD(&sclp_vt220_empty);
643 INIT_LIST_HEAD(&sclp_vt220_outqueue);
644 init_timer(&sclp_vt220_timer);
645 sclp_vt220_current_request = NULL;
646 sclp_vt220_buffered_chars = 0;
647 sclp_vt220_outqueue_count = 0;
648 sclp_vt220_tty = NULL;
649 sclp_vt220_flush_later = 0;
651 /* Allocate pages for output buffering */
652 num_pages = slab_is_available() ? MAX_KMEM_PAGES : MAX_CONSOLE_PAGES;
653 for (i = 0; i < num_pages; i++) {
654 if (slab_is_available())
655 page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
657 page = alloc_bootmem_low_pages(PAGE_SIZE);
659 __sclp_vt220_cleanup();
662 list_add_tail((struct list_head *) page, &sclp_vt220_empty);
664 rc = sclp_register(&sclp_vt220_register);
666 printk(KERN_ERR SCLP_VT220_PRINT_HEADER
667 "could not register vt220 - "
668 "sclp_register returned %d\n", rc);
669 __sclp_vt220_cleanup();
674 static const struct tty_operations sclp_vt220_ops = {
675 .open = sclp_vt220_open,
676 .close = sclp_vt220_close,
677 .write = sclp_vt220_write,
678 .put_char = sclp_vt220_put_char,
679 .flush_chars = sclp_vt220_flush_chars,
680 .write_room = sclp_vt220_write_room,
681 .chars_in_buffer = sclp_vt220_chars_in_buffer,
682 .flush_buffer = sclp_vt220_flush_buffer,
686 * Register driver with SCLP and Linux and initialize internal tty structures.
688 static int __init sclp_vt220_tty_init(void)
690 struct tty_driver *driver;
694 /* Note: we're not testing for CONSOLE_IS_SCLP here to preserve
695 * symmetry between VM and LPAR systems regarding ttyS1. */
696 driver = alloc_tty_driver(1);
699 cleanup = !sclp_vt220_initialized;
700 rc = __sclp_vt220_init();
704 driver->owner = THIS_MODULE;
705 driver->driver_name = SCLP_VT220_DRIVER_NAME;
706 driver->name = SCLP_VT220_DEVICE_NAME;
707 driver->major = SCLP_VT220_MAJOR;
708 driver->minor_start = SCLP_VT220_MINOR;
709 driver->type = TTY_DRIVER_TYPE_SYSTEM;
710 driver->subtype = SYSTEM_TYPE_TTY;
711 driver->init_termios = tty_std_termios;
712 driver->flags = TTY_DRIVER_REAL_RAW;
713 tty_set_operations(driver, &sclp_vt220_ops);
715 rc = tty_register_driver(driver);
717 printk(KERN_ERR SCLP_VT220_PRINT_HEADER
718 "could not register tty - "
719 "tty_register_driver returned %d\n", rc);
722 sclp_vt220_driver = driver;
727 __sclp_vt220_cleanup();
729 put_tty_driver(driver);
732 __initcall(sclp_vt220_tty_init);
734 #ifdef CONFIG_SCLP_VT220_CONSOLE
737 sclp_vt220_con_write(struct console *con, const char *buf, unsigned int count)
739 __sclp_vt220_write((const unsigned char *) buf, count, 1, 1, 0);
742 static struct tty_driver *
743 sclp_vt220_con_device(struct console *c, int *index)
746 return sclp_vt220_driver;
750 * This routine is called from panic when the kernel is going to give up.
751 * We have to make sure that all buffers will be flushed to the SCLP.
752 * Note that this function may be called from within an interrupt context.
755 sclp_vt220_con_unblank(void)
757 __sclp_vt220_flush_buffer();
760 /* Structure needed to register with printk */
761 static struct console sclp_vt220_console =
763 .name = SCLP_VT220_CONSOLE_NAME,
764 .write = sclp_vt220_con_write,
765 .device = sclp_vt220_con_device,
766 .unblank = sclp_vt220_con_unblank,
767 .flags = CON_PRINTBUFFER,
768 .index = SCLP_VT220_CONSOLE_INDEX
772 sclp_vt220_con_init(void)
776 if (!CONSOLE_IS_SCLP)
778 rc = __sclp_vt220_init();
781 /* Attach linux console */
782 register_console(&sclp_vt220_console);
786 console_initcall(sclp_vt220_con_init);
787 #endif /* CONFIG_SCLP_VT220_CONSOLE */