aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/char/snsc.c
blob: 0b799ac1b04957f501d4c50539f58e7ee28199cd (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
/*
 * SN Platform system controller communication support
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 2004, 2006 Silicon Graphics, Inc. All rights reserved.
 */

/*
 * System controller communication driver
 *
 * This driver allows a user process to communicate with the system
 * controller (a.k.a. "IRouter") network in an SGI SN system.
 */

#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/device.h>
#include <linux/poll.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/smp_lock.h>
#include <asm/sn/io.h>
#include <asm/sn/sn_sal.h>
#include <asm/sn/module.h>
#include <asm/sn/geo.h>
#include <asm/sn/nodepda.h>
#include "snsc.h"

#define SYSCTL_BASENAME	"snsc"

#define SCDRV_BUFSZ	2048
#define SCDRV_TIMEOUT	1000

static irqreturn_t
scdrv_interrupt(int irq, void *subch_data)
{
	struct subch_data_s *sd = subch_data;
	unsigned long flags;
	int status;

	spin_lock_irqsave(&sd->sd_rlock, flags);
	spin_lock(&sd->sd_wlock);
	status = ia64_sn_irtr_intr(sd->sd_nasid, sd->sd_subch);

	if (status > 0) {
		if (status & SAL_IROUTER_INTR_RECV) {
			wake_up(&sd->sd_rq);
		}
		if (status & SAL_IROUTER_INTR_XMIT) {
			ia64_sn_irtr_intr_disable
			    (sd->sd_nasid, sd->sd_subch,
			     SAL_IROUTER_INTR_XMIT);
			wake_up(&sd->sd_wq);
		}
	}
	spin_unlock(&sd->sd_wlock);
	spin_unlock_irqrestore(&sd->sd_rlock, flags);
	return IRQ_HANDLED;
}

/*
 * scdrv_open
 *
 * Reserve a subchannel for system controller communication.
 */

static int
scdrv_open(struct inode *inode, struct file *file)
{
	struct sysctl_data_s *scd;
	struct subch_data_s *sd;
	int rv;

	/* look up device info for this device file */
	scd = container_of(inode->i_cdev, struct sysctl_data_s, scd_cdev);

	/* allocate memory for subchannel data */
	sd = kzalloc(sizeof (struct subch_data_s), GFP_KERNEL);
	if (sd == NULL) {
		printk("%s: couldn't allocate subchannel data\n",
		       __func__);
		return -ENOMEM;
	}

	/* initialize subch_data_s fields */
	sd->sd_nasid = scd->scd_nasid;
	sd->sd_subch = ia64_sn_irtr_open(scd->scd_nasid);

	if (sd->sd_subch < 0) {
		kfree(sd);
		printk("%s: couldn't allocate subchannel\n", __func__);
		return -EBUSY;
	}

	spin_lock_init(&sd->sd_rlock);
	spin_lock_init(&sd->sd_wlock);
	init_waitqueue_head(&sd->sd_rq);
	init_waitqueue_head(&sd->sd_wq);
	sema_init(&sd->sd_rbs, 1);
	sema_init(&sd->sd_wbs, 1);

	file->private_data = sd;

	/* hook this subchannel up to the system controller interrupt */
	lock_kernel();
	rv = request_irq(SGI_UART_VECTOR, scdrv_interrupt,
			 IRQF_SHARED | IRQF_DISABLED,
			 SYSCTL_BASENAME, sd);
	if (rv) {
		ia64_sn_irtr_close(sd->sd_nasid, sd->sd_subch);
		kfree(sd);
		printk("%s: irq request failed (%d)\n", __func__, rv);
		unlock_kernel();
		return -EBUSY;
	}
	unlock_kernel();
	return 0;
}

/*
 * scdrv_release
 *
 * Release a previously-reserved subchannel.
 */

static int
scdrv_release(struct inode *inode, struct file *file)
{
	struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
	int rv;

	/* free the interrupt */
	free_irq(SGI_UART_VECTOR, sd);

	/* ask SAL to close the subchannel */
	rv = ia64_sn_irtr_close(sd->sd_nasid, sd->sd_subch);

	kfree(sd);
	return rv;
}

/*
 * scdrv_read
 *
 * Called to read bytes from the open IRouter pipe.
 *
 */

static inline int
read_status_check(struct subch_data_s *sd, int *len)
{
	return ia64_sn_irtr_recv(sd->sd_nasid, sd->sd_subch, sd->sd_rb, len);
}

static ssize_t
scdrv_read(struct file *file, char __user *buf, size_t count, loff_t *f_pos)
{
	int status;
	int len;
	unsigned long flags;
	struct subch_data_s *sd = (struct subch_data_s *) file->private_data;

	/* try to get control of the read buffer */
	if (down_trylock(&sd->sd_rbs)) {
		/* somebody else has it now;
		 * if we're non-blocking, then exit...
		 */
		if (file->f_flags & O_NONBLOCK) {
			return -EAGAIN;
		}
		/* ...or if we want to block, then do so here */
		if (down_interruptible(&sd->sd_rbs)) {
			/* something went wrong with wait */
			return -ERESTARTSYS;
		}
	}

	/* anything to read? */
	len = CHUNKSIZE;
	spin_lock_irqsave(&sd->sd_rlock, flags);
	status = read_status_check(sd, &len);

	/* if not, and we're blocking I/O, loop */
	while (status < 0) {
		DECLARE_WAITQUEUE(wait, current);

		if (file->f_flags & O_NONBLOCK) {
			spin_unlock_irqrestore(&sd->sd_rlock, flags);
			up(&sd->sd_rbs);
			return -EAGAIN;
		}

		len = CHUNKSIZE;
		set_current_state(TASK_INTERRUPTIBLE);
		add_wait_queue(&sd->sd_rq, &wait);
		spin_unlock_irqrestore(&sd->sd_rlock, flags);

		schedule_timeout(SCDRV_TIMEOUT);

		remove_wait_queue(&sd->sd_rq, &wait);
		if (signal_pending(current)) {
			/* wait was interrupted */
			up(&sd->sd_rbs);
			return -ERESTARTSYS;
		}

		spin_lock_irqsave(&sd->sd_rlock, flags);
		status = read_status_check(sd, &len);
	}
	spin_unlock_irqrestore(&sd->sd_rlock, flags);

	if (len > 0) {
		/* we read something in the last read_status_check(); copy
		 * it out to user space
		 */
		if (count < len) {
			pr_debug("%s: only accepting %d of %d bytes\n",
				 __func__, (int) count, len);
		}
		len = min((int) count, len);
		if (copy_to_user(buf, sd->sd_rb, len))
			len = -EFAULT;
	}

	/* release the read buffer and wake anyone who might be
	 * waiting for it
	 */
	up(&sd->sd_rbs);

	/* return the number of characters read in */
	return len;
}

/*
 * scdrv_write
 *
 * Writes a chunk of an IRouter packet (or other system controller data)
 * to the system controller.
 *
 */
static inline int
write_status_check(struct subch_data_s *sd, int count)
{
	return ia64_sn_irtr_send(sd->sd_nasid, sd->sd_subch, sd->sd_wb, count);
}

static ssize_t
scdrv_write(struct file *file, const char __user *buf,
	    size_t count, loff_t *f_pos)
{
	unsigned long flags;
	int status;
	struct subch_data_s *sd = (struct subch_data_s *) file->private_data;

	/* try to get control of the write buffer */
	if (down_trylock(&sd->sd_wbs)) {
		/* somebody else has it now;
		 * if we're non-blocking, then exit...
		 */
		if (file->f_flags & O_NONBLOCK) {
			return -EAGAIN;
		}
		/* ...or if we want to block, then do so here */
		if (down_interruptible(&sd->sd_wbs)) {
			/* something went wrong with wait */
			return -ERESTARTSYS;
		}
	}

	count = min((int) count, CHUNKSIZE);
	if (copy_from_user(sd->sd_wb, buf, count)) {
		up(&sd->sd_wbs);
		return -EFAULT;
	}

	/* try to send the buffer */
	spin_lock_irqsave(&sd->sd_wlock, flags);
	status = write_status_check(sd, count);

	/* if we failed, and we want to block, then loop */
	while (status <= 0) {
		DECLARE_WAITQUEUE(wait, current);

		if (file->f_flags & O_NONBLOCK) {
			spin_unlock(&sd->sd_wlock);
			up(&sd->sd_wbs);
			return -EAGAIN;
		}

		set_current_state(TASK_INTERRUPTIBLE);
		add_wait_queue(&sd->sd_wq, &wait);
		spin_unlock_irqrestore(&sd->sd_wlock, flags);

		schedule_timeout(SCDRV_TIMEOUT);

		remove_wait_queue(&sd->sd_wq, &wait);
		if (signal_pending(current)) {
			/* wait was interrupted */
			up(&sd->sd_wbs);
			return -ERESTARTSYS;
		}

		spin_lock_irqsave(&sd->sd_wlock, flags);
		status = write_status_check(sd, count);
	}
	spin_unlock_irqrestore(&sd->sd_wlock, flags);

	/* release the write buffer and wake anyone who's waiting for it */
	up(&sd->sd_wbs);

	/* return the number of characters accepted (should be the complete
	 * "chunk" as requested)
	 */
	if ((status >= 0) && (status < count)) {
		pr_debug("Didn't accept the full chunk; %d of %d\n",
			 status, (int) count);
	}
	return status;
}

static unsigned int
scdrv_poll(struct file *file, struct poll_table_struct *wait)
{
	unsigned int mask = 0;
	int status = 0;
	struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
	unsigned long flags;

	poll_wait(file, &sd->sd_rq, wait);
	poll_wait(file, &sd->sd_wq, wait);

	spin_lock_irqsave(&sd->sd_rlock, flags);
	spin_lock(&sd->sd_wlock);
	status = ia64_sn_irtr_intr(sd->sd_nasid, sd->sd_subch);
	spin_unlock(&sd->sd_wlock);
	spin_unlock_irqrestore(&sd->sd_rlock, flags);

	if (status > 0) {
		if (status & SAL_IROUTER_INTR_RECV) {
			mask |= POLLIN | POLLRDNORM;
		}
		if (status & SAL_IROUTER_INTR_XMIT) {
			mask |= POLLOUT | POLLWRNORM;
		}
	}

	return mask;
}

static const struct file_operations scdrv_fops = {
	.owner =	THIS_MODULE,
	.read =		scdrv_read,
	.write =	scdrv_write,
	.poll =		scdrv_poll,
	.open =		scdrv_open,
	.release =	scdrv_release,
};

static struct class *snsc_class;

/*
 * scdrv_init
 *
 * Called at boot time to initialize the system controller communication
 * facility.
 */
int __init
scdrv_init(void)
{
	geoid_t geoid;
	cnodeid_t cnode;
	char devname[32];
	char *devnamep;
	struct sysctl_data_s *scd;
	void *salbuf;
	dev_t first_dev, dev;
	nasid_t event_nasid;

	if (!ia64_platform_is("sn2"))
		return -ENODEV;

	event_nasid = ia64_sn_get_console_nasid();

	if (alloc_chrdev_region(&first_dev, 0, num_cnodes,
				SYSCTL_BASENAME) < 0) {
		printk("%s: failed to register SN system controller device\n",
		       __func__);
		return -ENODEV;
	}
	snsc_class = class_create(THIS_MODULE, SYSCTL_BASENAME);

	for (cnode = 0; cnode < num_cnodes; cnode++) {
			geoid = cnodeid_get_geoid(cnode);
			devnamep = devname;
			format_module_id(devnamep, geo_module(geoid),
					 MODULE_FORMAT_BRIEF);
			devnamep = devname + strlen(devname);
			sprintf(devnamep, "^%d#%d", geo_slot(geoid),
				geo_slab(geoid));

			/* allocate sysctl device data */
			scd = kzalloc(sizeof (struct sysctl_data_s),
				      GFP_KERNEL);
			if (!scd) {
				printk("%s: failed to allocate device info"
				       "for %s/%s\n", __func__,
				       SYSCTL_BASENAME, devname);
				continue;
			}

			/* initialize sysctl device data fields */
			scd->scd_nasid = cnodeid_to_nasid(cnode);
			if (!(salbuf = kmalloc(SCDRV_BUFSZ, GFP_KERNEL))) {
				printk("%s: failed to allocate driver buffer"
				       "(%s%s)\n", __func__,
				       SYSCTL_BASENAME, devname);
				kfree(scd);
				continue;
			}

			if (ia64_sn_irtr_init(scd->scd_nasid, salbuf,
					      SCDRV_BUFSZ) < 0) {
				printk
				    ("%s: failed to initialize SAL for"
				     " system controller communication"
				     " (%s/%s): outdated PROM?\n",
				     __func__, SYSCTL_BASENAME, devname);
				kfree(scd);
				kfree(salbuf);
				continue;
			}

			dev = first_dev + cnode;
			cdev_init(&scd->scd_cdev, &scdrv_fops);
			if (cdev_add(&scd->scd_cdev, dev, 1)) {
				printk("%s: failed to register system"
				       " controller device (%s%s)\n",
				       __func__, SYSCTL_BASENAME, devname);
				kfree(scd);
				kfree(salbuf);
				continue;
			}

			device_create(snsc_class, NULL, dev, "%s", devname);

			ia64_sn_irtr_intr_enable(scd->scd_nasid,
						 0 /*ignored */ ,
						 SAL_IROUTER_INTR_RECV);

                        /* on the console nasid, prepare to receive
                         * system controller environmental events
                         */
                        if(scd->scd_nasid == event_nasid) {
                                scdrv_event_init(scd);
                        }
	}
	return 0;
}

module_init(scdrv_init);