1// SPDX-License-Identifier: GPL-2.0
2/*
3 * IBM/3270 Driver - fullscreen driver.
4 *
5 * Author(s):
6 *   Original 3270 Code for 2.4 written by Richard Hitt (UTS Global)
7 *   Rewritten for 2.5/2.6 by Martin Schwidefsky <schwidefsky@de.ibm.com>
8 *     Copyright IBM Corp. 2003, 2009
9 */
10
11#include <linux/memblock.h>
12#include <linux/console.h>
13#include <linux/init.h>
14#include <linux/interrupt.h>
15#include <linux/compat.h>
16#include <linux/sched/signal.h>
17#include <linux/module.h>
18#include <linux/list.h>
19#include <linux/slab.h>
20#include <linux/types.h>
21
22#include <uapi/asm/fs3270.h>
23#include <asm/ccwdev.h>
24#include <asm/cio.h>
25#include <asm/ebcdic.h>
26#include <asm/idals.h>
27
28#include "raw3270.h"
29#include "ctrlchar.h"
30
31static struct raw3270_fn fs3270_fn;
32
33struct fs3270 {
34	struct raw3270_view view;
35	struct pid *fs_pid;		/* Pid of controlling program. */
36	int read_command;		/* ccw command to use for reads. */
37	int write_command;		/* ccw command to use for writes. */
38	int attention;			/* Got attention. */
39	int active;			/* Fullscreen view is active. */
40	struct raw3270_request *init;	/* single init request. */
41	wait_queue_head_t wait;		/* Init & attention wait queue. */
42	struct idal_buffer *rdbuf;	/* full-screen-deactivate buffer */
43	size_t rdbuf_size;		/* size of data returned by RDBUF */
44};
45
46static DEFINE_MUTEX(fs3270_mutex);
47
48static void fs3270_wake_up(struct raw3270_request *rq, void *data)
49{
50	wake_up((wait_queue_head_t *)data);
51}
52
53static inline int fs3270_working(struct fs3270 *fp)
54{
55	/*
56	 * The fullscreen view is in working order if the view
57	 * has been activated AND the initial request is finished.
58	 */
59	return fp->active && raw3270_request_final(fp->init);
60}
61
62static int fs3270_do_io(struct raw3270_view *view, struct raw3270_request *rq)
63{
64	struct fs3270 *fp;
65	int rc;
66
67	fp = (struct fs3270 *)view;
68	rq->callback = fs3270_wake_up;
69	rq->callback_data = &fp->wait;
70
71	do {
72		if (!fs3270_working(fp)) {
73			/* Fullscreen view isn't ready yet. */
74			rc = wait_event_interruptible(fp->wait,
75						      fs3270_working(fp));
76			if (rc != 0)
77				break;
78		}
79		rc = raw3270_start(view, rq);
80		if (rc == 0) {
81			/* Started successfully. Now wait for completion. */
82			wait_event(fp->wait, raw3270_request_final(rq));
83		}
84	} while (rc == -EACCES);
85	return rc;
86}
87
88/*
89 * Switch to the fullscreen view.
90 */
91static void fs3270_reset_callback(struct raw3270_request *rq, void *data)
92{
93	struct fs3270 *fp;
94
95	fp = (struct fs3270 *)rq->view;
96	raw3270_request_reset(rq);
97	wake_up(&fp->wait);
98}
99
100static void fs3270_restore_callback(struct raw3270_request *rq, void *data)
101{
102	struct fs3270 *fp;
103
104	fp = (struct fs3270 *)rq->view;
105	if (rq->rc != 0 || rq->rescnt != 0) {
106		if (fp->fs_pid)
107			kill_pid(fp->fs_pid, SIGHUP, 1);
108	}
109	fp->rdbuf_size = 0;
110	raw3270_request_reset(rq);
111	wake_up(&fp->wait);
112}
113
114static int fs3270_activate(struct raw3270_view *view)
115{
116	struct fs3270 *fp;
117	char *cp;
118	int rc;
119
120	fp = (struct fs3270 *)view;
121
122	/* If an old init command is still running just return. */
123	if (!raw3270_request_final(fp->init))
124		return 0;
125
126	raw3270_request_set_cmd(fp->init, TC_EWRITEA);
127	raw3270_request_set_idal(fp->init, fp->rdbuf);
128	fp->init->rescnt = 0;
129	cp = dma64_to_virt(fp->rdbuf->data[0]);
130	if (fp->rdbuf_size == 0) {
131		/* No saved buffer. Just clear the screen. */
132		fp->init->ccw.count = 1;
133		fp->init->callback = fs3270_reset_callback;
134		cp[0] = 0;
135	} else {
136		/* Restore fullscreen buffer saved by fs3270_deactivate. */
137		fp->init->ccw.count = fp->rdbuf_size;
138		fp->init->callback = fs3270_restore_callback;
139		cp[0] = TW_KR;
140		cp[1] = TO_SBA;
141		cp[2] = cp[6];
142		cp[3] = cp[7];
143		cp[4] = TO_IC;
144		cp[5] = TO_SBA;
145		cp[6] = 0x40;
146		cp[7] = 0x40;
147	}
148	rc = raw3270_start_locked(view, fp->init);
149	fp->init->rc = rc;
150	if (rc)
151		fp->init->callback(fp->init, NULL);
152	else
153		fp->active = 1;
154	return rc;
155}
156
157/*
158 * Shutdown fullscreen view.
159 */
160static void fs3270_save_callback(struct raw3270_request *rq, void *data)
161{
162	struct fs3270 *fp;
163
164	fp = (struct fs3270 *)rq->view;
165
166	/* Correct idal buffer element 0 address. */
167	fp->rdbuf->data[0] = dma64_add(fp->rdbuf->data[0], -5);
168	fp->rdbuf->size += 5;
169
170	/*
171	 * If the rdbuf command failed or the idal buffer is
172	 * to small for the amount of data returned by the
173	 * rdbuf command, then we have no choice but to send
174	 * a SIGHUP to the application.
175	 */
176	if (rq->rc != 0 || rq->rescnt == 0) {
177		if (fp->fs_pid)
178			kill_pid(fp->fs_pid, SIGHUP, 1);
179		fp->rdbuf_size = 0;
180	} else {
181		fp->rdbuf_size = fp->rdbuf->size - rq->rescnt;
182	}
183	raw3270_request_reset(rq);
184	wake_up(&fp->wait);
185}
186
187static void fs3270_deactivate(struct raw3270_view *view)
188{
189	struct fs3270 *fp;
190
191	fp = (struct fs3270 *)view;
192	fp->active = 0;
193
194	/* If an old init command is still running just return. */
195	if (!raw3270_request_final(fp->init))
196		return;
197
198	/* Prepare read-buffer request. */
199	raw3270_request_set_cmd(fp->init, TC_RDBUF);
200	/*
201	 * Hackish: skip first 5 bytes of the idal buffer to make
202	 * room for the TW_KR/TO_SBA/<address>/<address>/TO_IC sequence
203	 * in the activation command.
204	 */
205	fp->rdbuf->data[0] = dma64_add(fp->rdbuf->data[0], 5);
206	fp->rdbuf->size -= 5;
207	raw3270_request_set_idal(fp->init, fp->rdbuf);
208	fp->init->rescnt = 0;
209	fp->init->callback = fs3270_save_callback;
210
211	/* Start I/O to read in the 3270 buffer. */
212	fp->init->rc = raw3270_start_locked(view, fp->init);
213	if (fp->init->rc)
214		fp->init->callback(fp->init, NULL);
215}
216
217static void fs3270_irq(struct fs3270 *fp, struct raw3270_request *rq,
218		       struct irb *irb)
219{
220	/* Handle ATTN. Set indication and wake waiters for attention. */
221	if (irb->scsw.cmd.dstat & DEV_STAT_ATTENTION) {
222		fp->attention = 1;
223		wake_up(&fp->wait);
224	}
225
226	if (rq) {
227		if (irb->scsw.cmd.dstat & DEV_STAT_UNIT_CHECK)
228			rq->rc = -EIO;
229		else
230			/* Normal end. Copy residual count. */
231			rq->rescnt = irb->scsw.cmd.count;
232	}
233}
234
235/*
236 * Process reads from fullscreen 3270.
237 */
238static ssize_t fs3270_read(struct file *filp, char __user *data,
239			   size_t count, loff_t *off)
240{
241	struct fs3270 *fp;
242	struct raw3270_request *rq;
243	struct idal_buffer *ib;
244	ssize_t rc;
245
246	if (count == 0 || count > 65535)
247		return -EINVAL;
248	fp = filp->private_data;
249	if (!fp)
250		return -ENODEV;
251	ib = idal_buffer_alloc(count, 0);
252	if (IS_ERR(ib))
253		return -ENOMEM;
254	rq = raw3270_request_alloc(0);
255	if (!IS_ERR(rq)) {
256		if (fp->read_command == 0 && fp->write_command != 0)
257			fp->read_command = 6;
258		raw3270_request_set_cmd(rq, fp->read_command ? : 2);
259		raw3270_request_set_idal(rq, ib);
260		rc = wait_event_interruptible(fp->wait, fp->attention);
261		fp->attention = 0;
262		if (rc == 0) {
263			rc = fs3270_do_io(&fp->view, rq);
264			if (rc == 0) {
265				count -= rq->rescnt;
266				if (idal_buffer_to_user(ib, data, count) != 0)
267					rc = -EFAULT;
268				else
269					rc = count;
270			}
271		}
272		raw3270_request_free(rq);
273	} else {
274		rc = PTR_ERR(rq);
275	}
276	idal_buffer_free(ib);
277	return rc;
278}
279
280/*
281 * Process writes to fullscreen 3270.
282 */
283static ssize_t fs3270_write(struct file *filp, const char __user *data,
284			    size_t count, loff_t *off)
285{
286	struct fs3270 *fp;
287	struct raw3270_request *rq;
288	struct idal_buffer *ib;
289	int write_command;
290	ssize_t rc;
291
292	fp = filp->private_data;
293	if (!fp)
294		return -ENODEV;
295	ib = idal_buffer_alloc(count, 0);
296	if (IS_ERR(ib))
297		return -ENOMEM;
298	rq = raw3270_request_alloc(0);
299	if (!IS_ERR(rq)) {
300		if (idal_buffer_from_user(ib, data, count) == 0) {
301			write_command = fp->write_command ? : 1;
302			if (write_command == 5)
303				write_command = 13;
304			raw3270_request_set_cmd(rq, write_command);
305			raw3270_request_set_idal(rq, ib);
306			rc = fs3270_do_io(&fp->view, rq);
307			if (rc == 0)
308				rc = count - rq->rescnt;
309		} else {
310			rc = -EFAULT;
311		}
312		raw3270_request_free(rq);
313	} else {
314		rc = PTR_ERR(rq);
315	}
316	idal_buffer_free(ib);
317	return rc;
318}
319
320/*
321 * process ioctl commands for the tube driver
322 */
323static long fs3270_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
324{
325	char __user *argp;
326	struct fs3270 *fp;
327	struct raw3270_iocb iocb;
328	int rc;
329
330	fp = filp->private_data;
331	if (!fp)
332		return -ENODEV;
333	if (is_compat_task())
334		argp = compat_ptr(arg);
335	else
336		argp = (char __user *)arg;
337	rc = 0;
338	mutex_lock(&fs3270_mutex);
339	switch (cmd) {
340	case TUBICMD:
341		fp->read_command = arg;
342		break;
343	case TUBOCMD:
344		fp->write_command = arg;
345		break;
346	case TUBGETI:
347		rc = put_user(fp->read_command, argp);
348		break;
349	case TUBGETO:
350		rc = put_user(fp->write_command, argp);
351		break;
352	case TUBGETMOD:
353		iocb.model = fp->view.model;
354		iocb.line_cnt = fp->view.rows;
355		iocb.col_cnt = fp->view.cols;
356		iocb.pf_cnt = 24;
357		iocb.re_cnt = 20;
358		iocb.map = 0;
359		if (copy_to_user(argp, &iocb, sizeof(struct raw3270_iocb)))
360			rc = -EFAULT;
361		break;
362	}
363	mutex_unlock(&fs3270_mutex);
364	return rc;
365}
366
367/*
368 * Allocate fs3270 structure.
369 */
370static struct fs3270 *fs3270_alloc_view(void)
371{
372	struct fs3270 *fp;
373
374	fp = kzalloc(sizeof(*fp), GFP_KERNEL);
375	if (!fp)
376		return ERR_PTR(-ENOMEM);
377	fp->init = raw3270_request_alloc(0);
378	if (IS_ERR(fp->init)) {
379		kfree(fp);
380		return ERR_PTR(-ENOMEM);
381	}
382	return fp;
383}
384
385/*
386 * Free fs3270 structure.
387 */
388static void fs3270_free_view(struct raw3270_view *view)
389{
390	struct fs3270 *fp;
391
392	fp = (struct fs3270 *)view;
393	if (fp->rdbuf)
394		idal_buffer_free(fp->rdbuf);
395	raw3270_request_free(((struct fs3270 *)view)->init);
396	kfree(view);
397}
398
399/*
400 * Unlink fs3270 data structure from filp.
401 */
402static void fs3270_release(struct raw3270_view *view)
403{
404	struct fs3270 *fp;
405
406	fp = (struct fs3270 *)view;
407	if (fp->fs_pid)
408		kill_pid(fp->fs_pid, SIGHUP, 1);
409}
410
411/* View to a 3270 device. Can be console, tty or fullscreen. */
412static struct raw3270_fn fs3270_fn = {
413	.activate = fs3270_activate,
414	.deactivate = fs3270_deactivate,
415	.intv = (void *)fs3270_irq,
416	.release = fs3270_release,
417	.free = fs3270_free_view
418};
419
420/*
421 * This routine is called whenever a 3270 fullscreen device is opened.
422 */
423static int fs3270_open(struct inode *inode, struct file *filp)
424{
425	struct fs3270 *fp;
426	struct idal_buffer *ib;
427	int minor, rc = 0;
428
429	if (imajor(file_inode(filp)) != IBM_FS3270_MAJOR)
430		return -ENODEV;
431	minor = iminor(file_inode(filp));
432	/* Check for minor 0 multiplexer. */
433	if (minor == 0) {
434		struct tty_struct *tty = get_current_tty();
435
436		if (!tty || tty->driver->major != IBM_TTY3270_MAJOR) {
437			tty_kref_put(tty);
438			return -ENODEV;
439		}
440		minor = tty->index;
441		tty_kref_put(tty);
442	}
443	mutex_lock(&fs3270_mutex);
444	/* Check if some other program is already using fullscreen mode. */
445	fp = (struct fs3270 *)raw3270_find_view(&fs3270_fn, minor);
446	if (!IS_ERR(fp)) {
447		raw3270_put_view(&fp->view);
448		rc = -EBUSY;
449		goto out;
450	}
451	/* Allocate fullscreen view structure. */
452	fp = fs3270_alloc_view();
453	if (IS_ERR(fp)) {
454		rc = PTR_ERR(fp);
455		goto out;
456	}
457
458	init_waitqueue_head(&fp->wait);
459	fp->fs_pid = get_pid(task_pid(current));
460	rc = raw3270_add_view(&fp->view, &fs3270_fn, minor,
461			      RAW3270_VIEW_LOCK_BH);
462	if (rc) {
463		fs3270_free_view(&fp->view);
464		goto out;
465	}
466
467	/* Allocate idal-buffer. */
468	ib = idal_buffer_alloc(2 * fp->view.rows * fp->view.cols + 5, 0);
469	if (IS_ERR(ib)) {
470		raw3270_put_view(&fp->view);
471		raw3270_del_view(&fp->view);
472		rc = PTR_ERR(ib);
473		goto out;
474	}
475	fp->rdbuf = ib;
476
477	rc = raw3270_activate_view(&fp->view);
478	if (rc) {
479		raw3270_put_view(&fp->view);
480		raw3270_del_view(&fp->view);
481		goto out;
482	}
483	stream_open(inode, filp);
484	filp->private_data = fp;
485out:
486	mutex_unlock(&fs3270_mutex);
487	return rc;
488}
489
490/*
491 * This routine is called when the 3270 tty is closed. We wait
492 * for the remaining request to be completed. Then we clean up.
493 */
494static int fs3270_close(struct inode *inode, struct file *filp)
495{
496	struct fs3270 *fp;
497
498	fp = filp->private_data;
499	filp->private_data = NULL;
500	if (fp) {
501		put_pid(fp->fs_pid);
502		fp->fs_pid = NULL;
503		raw3270_reset(&fp->view);
504		raw3270_put_view(&fp->view);
505		raw3270_del_view(&fp->view);
506	}
507	return 0;
508}
509
510static const struct file_operations fs3270_fops = {
511	.owner		 = THIS_MODULE,		/* owner */
512	.read		 = fs3270_read,		/* read */
513	.write		 = fs3270_write,	/* write */
514	.unlocked_ioctl	 = fs3270_ioctl,	/* ioctl */
515	.compat_ioctl	 = fs3270_ioctl,	/* ioctl */
516	.open		 = fs3270_open,		/* open */
517	.release	 = fs3270_close,	/* release */
518	.llseek		= no_llseek,
519};
520
521static void fs3270_create_cb(int minor)
522{
523	__register_chrdev(IBM_FS3270_MAJOR, minor, 1, "tub", &fs3270_fops);
524	device_create(&class3270, NULL, MKDEV(IBM_FS3270_MAJOR, minor),
525		      NULL, "3270/tub%d", minor);
526}
527
528static void fs3270_destroy_cb(int minor)
529{
530	device_destroy(&class3270, MKDEV(IBM_FS3270_MAJOR, minor));
531	__unregister_chrdev(IBM_FS3270_MAJOR, minor, 1, "tub");
532}
533
534static struct raw3270_notifier fs3270_notifier = {
535	.create = fs3270_create_cb,
536	.destroy = fs3270_destroy_cb,
537};
538
539/*
540 * 3270 fullscreen driver initialization.
541 */
542static int __init fs3270_init(void)
543{
544	int rc;
545
546	rc = __register_chrdev(IBM_FS3270_MAJOR, 0, 1, "fs3270", &fs3270_fops);
547	if (rc)
548		return rc;
549	device_create(&class3270, NULL, MKDEV(IBM_FS3270_MAJOR, 0),
550		      NULL, "3270/tub");
551	raw3270_register_notifier(&fs3270_notifier);
552	return 0;
553}
554
555static void __exit fs3270_exit(void)
556{
557	raw3270_unregister_notifier(&fs3270_notifier);
558	device_destroy(&class3270, MKDEV(IBM_FS3270_MAJOR, 0));
559	__unregister_chrdev(IBM_FS3270_MAJOR, 0, 1, "fs3270");
560}
561
562MODULE_LICENSE("GPL");
563MODULE_ALIAS_CHARDEV_MAJOR(IBM_FS3270_MAJOR);
564
565module_init(fs3270_init);
566module_exit(fs3270_exit);
567