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1/*
2 * SN Platform system controller communication support
3 *
4 * This file is subject to the terms and conditions of the GNU General Public
5 * License. See the file "COPYING" in the main directory of this archive
6 * for more details.
7 *
8 * Copyright (C) 2004, 2006 Silicon Graphics, Inc. All rights reserved.
9 */
10
11/*
12 * System controller communication driver
13 *
14 * This driver allows a user process to communicate with the system
15 * controller (a.k.a. "IRouter") network in an SGI SN system.
16 */
17
18#include <linux/interrupt.h>
19#include <linux/sched.h>
20#include <linux/device.h>
21#include <linux/poll.h>
22#include <linux/module.h>
23#include <linux/slab.h>
24#include <linux/mutex.h>
25#include <asm/sn/io.h>
26#include <asm/sn/sn_sal.h>
27#include <asm/sn/module.h>
28#include <asm/sn/geo.h>
29#include <asm/sn/nodepda.h>
30#include "snsc.h"
31
32#define SYSCTL_BASENAME "snsc"
33
34#define SCDRV_BUFSZ 2048
35#define SCDRV_TIMEOUT 1000
36
37static DEFINE_MUTEX(scdrv_mutex);
38static irqreturn_t
39scdrv_interrupt(int irq, void *subch_data)
40{
41 struct subch_data_s *sd = subch_data;
42 unsigned long flags;
43 int status;
44
45 spin_lock_irqsave(&sd->sd_rlock, flags);
46 spin_lock(&sd->sd_wlock);
47 status = ia64_sn_irtr_intr(sd->sd_nasid, sd->sd_subch);
48
49 if (status > 0) {
50 if (status & SAL_IROUTER_INTR_RECV) {
51 wake_up(&sd->sd_rq);
52 }
53 if (status & SAL_IROUTER_INTR_XMIT) {
54 ia64_sn_irtr_intr_disable
55 (sd->sd_nasid, sd->sd_subch,
56 SAL_IROUTER_INTR_XMIT);
57 wake_up(&sd->sd_wq);
58 }
59 }
60 spin_unlock(&sd->sd_wlock);
61 spin_unlock_irqrestore(&sd->sd_rlock, flags);
62 return IRQ_HANDLED;
63}
64
65/*
66 * scdrv_open
67 *
68 * Reserve a subchannel for system controller communication.
69 */
70
71static int
72scdrv_open(struct inode *inode, struct file *file)
73{
74 struct sysctl_data_s *scd;
75 struct subch_data_s *sd;
76 int rv;
77
78 /* look up device info for this device file */
79 scd = container_of(inode->i_cdev, struct sysctl_data_s, scd_cdev);
80
81 /* allocate memory for subchannel data */
82 sd = kzalloc(sizeof (struct subch_data_s), GFP_KERNEL);
83 if (sd == NULL) {
84 printk("%s: couldn't allocate subchannel data\n",
85 __func__);
86 return -ENOMEM;
87 }
88
89 /* initialize subch_data_s fields */
90 sd->sd_nasid = scd->scd_nasid;
91 sd->sd_subch = ia64_sn_irtr_open(scd->scd_nasid);
92
93 if (sd->sd_subch < 0) {
94 kfree(sd);
95 printk("%s: couldn't allocate subchannel\n", __func__);
96 return -EBUSY;
97 }
98
99 spin_lock_init(&sd->sd_rlock);
100 spin_lock_init(&sd->sd_wlock);
101 init_waitqueue_head(&sd->sd_rq);
102 init_waitqueue_head(&sd->sd_wq);
103 sema_init(&sd->sd_rbs, 1);
104 sema_init(&sd->sd_wbs, 1);
105
106 file->private_data = sd;
107
108 /* hook this subchannel up to the system controller interrupt */
109 mutex_lock(&scdrv_mutex);
110 rv = request_irq(SGI_UART_VECTOR, scdrv_interrupt,
111 IRQF_SHARED | IRQF_DISABLED,
112 SYSCTL_BASENAME, sd);
113 if (rv) {
114 ia64_sn_irtr_close(sd->sd_nasid, sd->sd_subch);
115 kfree(sd);
116 printk("%s: irq request failed (%d)\n", __func__, rv);
117 mutex_unlock(&scdrv_mutex);
118 return -EBUSY;
119 }
120 mutex_unlock(&scdrv_mutex);
121 return 0;
122}
123
124/*
125 * scdrv_release
126 *
127 * Release a previously-reserved subchannel.
128 */
129
130static int
131scdrv_release(struct inode *inode, struct file *file)
132{
133 struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
134 int rv;
135
136 /* free the interrupt */
137 free_irq(SGI_UART_VECTOR, sd);
138
139 /* ask SAL to close the subchannel */
140 rv = ia64_sn_irtr_close(sd->sd_nasid, sd->sd_subch);
141
142 kfree(sd);
143 return rv;
144}
145
146/*
147 * scdrv_read
148 *
149 * Called to read bytes from the open IRouter pipe.
150 *
151 */
152
153static inline int
154read_status_check(struct subch_data_s *sd, int *len)
155{
156 return ia64_sn_irtr_recv(sd->sd_nasid, sd->sd_subch, sd->sd_rb, len);
157}
158
159static ssize_t
160scdrv_read(struct file *file, char __user *buf, size_t count, loff_t *f_pos)
161{
162 int status;
163 int len;
164 unsigned long flags;
165 struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
166
167 /* try to get control of the read buffer */
168 if (down_trylock(&sd->sd_rbs)) {
169 /* somebody else has it now;
170 * if we're non-blocking, then exit...
171 */
172 if (file->f_flags & O_NONBLOCK) {
173 return -EAGAIN;
174 }
175 /* ...or if we want to block, then do so here */
176 if (down_interruptible(&sd->sd_rbs)) {
177 /* something went wrong with wait */
178 return -ERESTARTSYS;
179 }
180 }
181
182 /* anything to read? */
183 len = CHUNKSIZE;
184 spin_lock_irqsave(&sd->sd_rlock, flags);
185 status = read_status_check(sd, &len);
186
187 /* if not, and we're blocking I/O, loop */
188 while (status < 0) {
189 DECLARE_WAITQUEUE(wait, current);
190
191 if (file->f_flags & O_NONBLOCK) {
192 spin_unlock_irqrestore(&sd->sd_rlock, flags);
193 up(&sd->sd_rbs);
194 return -EAGAIN;
195 }
196
197 len = CHUNKSIZE;
198 set_current_state(TASK_INTERRUPTIBLE);
199 add_wait_queue(&sd->sd_rq, &wait);
200 spin_unlock_irqrestore(&sd->sd_rlock, flags);
201
202 schedule_timeout(SCDRV_TIMEOUT);
203
204 remove_wait_queue(&sd->sd_rq, &wait);
205 if (signal_pending(current)) {
206 /* wait was interrupted */
207 up(&sd->sd_rbs);
208 return -ERESTARTSYS;
209 }
210
211 spin_lock_irqsave(&sd->sd_rlock, flags);
212 status = read_status_check(sd, &len);
213 }
214 spin_unlock_irqrestore(&sd->sd_rlock, flags);
215
216 if (len > 0) {
217 /* we read something in the last read_status_check(); copy
218 * it out to user space
219 */
220 if (count < len) {
221 pr_debug("%s: only accepting %d of %d bytes\n",
222 __func__, (int) count, len);
223 }
224 len = min((int) count, len);
225 if (copy_to_user(buf, sd->sd_rb, len))
226 len = -EFAULT;
227 }
228
229 /* release the read buffer and wake anyone who might be
230 * waiting for it
231 */
232 up(&sd->sd_rbs);
233
234 /* return the number of characters read in */
235 return len;
236}
237
238/*
239 * scdrv_write
240 *
241 * Writes a chunk of an IRouter packet (or other system controller data)
242 * to the system controller.
243 *
244 */
245static inline int
246write_status_check(struct subch_data_s *sd, int count)
247{
248 return ia64_sn_irtr_send(sd->sd_nasid, sd->sd_subch, sd->sd_wb, count);
249}
250
251static ssize_t
252scdrv_write(struct file *file, const char __user *buf,
253 size_t count, loff_t *f_pos)
254{
255 unsigned long flags;
256 int status;
257 struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
258
259 /* try to get control of the write buffer */
260 if (down_trylock(&sd->sd_wbs)) {
261 /* somebody else has it now;
262 * if we're non-blocking, then exit...
263 */
264 if (file->f_flags & O_NONBLOCK) {
265 return -EAGAIN;
266 }
267 /* ...or if we want to block, then do so here */
268 if (down_interruptible(&sd->sd_wbs)) {
269 /* something went wrong with wait */
270 return -ERESTARTSYS;
271 }
272 }
273
274 count = min((int) count, CHUNKSIZE);
275 if (copy_from_user(sd->sd_wb, buf, count)) {
276 up(&sd->sd_wbs);
277 return -EFAULT;
278 }
279
280 /* try to send the buffer */
281 spin_lock_irqsave(&sd->sd_wlock, flags);
282 status = write_status_check(sd, count);
283
284 /* if we failed, and we want to block, then loop */
285 while (status <= 0) {
286 DECLARE_WAITQUEUE(wait, current);
287
288 if (file->f_flags & O_NONBLOCK) {
289 spin_unlock(&sd->sd_wlock);
290 up(&sd->sd_wbs);
291 return -EAGAIN;
292 }
293
294 set_current_state(TASK_INTERRUPTIBLE);
295 add_wait_queue(&sd->sd_wq, &wait);
296 spin_unlock_irqrestore(&sd->sd_wlock, flags);
297
298 schedule_timeout(SCDRV_TIMEOUT);
299
300 remove_wait_queue(&sd->sd_wq, &wait);
301 if (signal_pending(current)) {
302 /* wait was interrupted */
303 up(&sd->sd_wbs);
304 return -ERESTARTSYS;
305 }
306
307 spin_lock_irqsave(&sd->sd_wlock, flags);
308 status = write_status_check(sd, count);
309 }
310 spin_unlock_irqrestore(&sd->sd_wlock, flags);
311
312 /* release the write buffer and wake anyone who's waiting for it */
313 up(&sd->sd_wbs);
314
315 /* return the number of characters accepted (should be the complete
316 * "chunk" as requested)
317 */
318 if ((status >= 0) && (status < count)) {
319 pr_debug("Didn't accept the full chunk; %d of %d\n",
320 status, (int) count);
321 }
322 return status;
323}
324
325static unsigned int
326scdrv_poll(struct file *file, struct poll_table_struct *wait)
327{
328 unsigned int mask = 0;
329 int status = 0;
330 struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
331 unsigned long flags;
332
333 poll_wait(file, &sd->sd_rq, wait);
334 poll_wait(file, &sd->sd_wq, wait);
335
336 spin_lock_irqsave(&sd->sd_rlock, flags);
337 spin_lock(&sd->sd_wlock);
338 status = ia64_sn_irtr_intr(sd->sd_nasid, sd->sd_subch);
339 spin_unlock(&sd->sd_wlock);
340 spin_unlock_irqrestore(&sd->sd_rlock, flags);
341
342 if (status > 0) {
343 if (status & SAL_IROUTER_INTR_RECV) {
344 mask |= POLLIN | POLLRDNORM;
345 }
346 if (status & SAL_IROUTER_INTR_XMIT) {
347 mask |= POLLOUT | POLLWRNORM;
348 }
349 }
350
351 return mask;
352}
353
354static const struct file_operations scdrv_fops = {
355 .owner = THIS_MODULE,
356 .read = scdrv_read,
357 .write = scdrv_write,
358 .poll = scdrv_poll,
359 .open = scdrv_open,
360 .release = scdrv_release,
361 .llseek = noop_llseek,
362};
363
364static struct class *snsc_class;
365
366/*
367 * scdrv_init
368 *
369 * Called at boot time to initialize the system controller communication
370 * facility.
371 */
372int __init
373scdrv_init(void)
374{
375 geoid_t geoid;
376 cnodeid_t cnode;
377 char devname[32];
378 char *devnamep;
379 struct sysctl_data_s *scd;
380 void *salbuf;
381 dev_t first_dev, dev;
382 nasid_t event_nasid;
383
384 if (!ia64_platform_is("sn2"))
385 return -ENODEV;
386
387 event_nasid = ia64_sn_get_console_nasid();
388
389 if (alloc_chrdev_region(&first_dev, 0, num_cnodes,
390 SYSCTL_BASENAME) < 0) {
391 printk("%s: failed to register SN system controller device\n",
392 __func__);
393 return -ENODEV;
394 }
395 snsc_class = class_create(THIS_MODULE, SYSCTL_BASENAME);
396
397 for (cnode = 0; cnode < num_cnodes; cnode++) {
398 geoid = cnodeid_get_geoid(cnode);
399 devnamep = devname;
400 format_module_id(devnamep, geo_module(geoid),
401 MODULE_FORMAT_BRIEF);
402 devnamep = devname + strlen(devname);
403 sprintf(devnamep, "^%d#%d", geo_slot(geoid),
404 geo_slab(geoid));
405
406 /* allocate sysctl device data */
407 scd = kzalloc(sizeof (struct sysctl_data_s),
408 GFP_KERNEL);
409 if (!scd) {
410 printk("%s: failed to allocate device info"
411 "for %s/%s\n", __func__,
412 SYSCTL_BASENAME, devname);
413 continue;
414 }
415
416 /* initialize sysctl device data fields */
417 scd->scd_nasid = cnodeid_to_nasid(cnode);
418 if (!(salbuf = kmalloc(SCDRV_BUFSZ, GFP_KERNEL))) {
419 printk("%s: failed to allocate driver buffer"
420 "(%s%s)\n", __func__,
421 SYSCTL_BASENAME, devname);
422 kfree(scd);
423 continue;
424 }
425
426 if (ia64_sn_irtr_init(scd->scd_nasid, salbuf,
427 SCDRV_BUFSZ) < 0) {
428 printk
429 ("%s: failed to initialize SAL for"
430 " system controller communication"
431 " (%s/%s): outdated PROM?\n",
432 __func__, SYSCTL_BASENAME, devname);
433 kfree(scd);
434 kfree(salbuf);
435 continue;
436 }
437
438 dev = first_dev + cnode;
439 cdev_init(&scd->scd_cdev, &scdrv_fops);
440 if (cdev_add(&scd->scd_cdev, dev, 1)) {
441 printk("%s: failed to register system"
442 " controller device (%s%s)\n",
443 __func__, SYSCTL_BASENAME, devname);
444 kfree(scd);
445 kfree(salbuf);
446 continue;
447 }
448
449 device_create(snsc_class, NULL, dev, NULL,
450 "%s", devname);
451
452 ia64_sn_irtr_intr_enable(scd->scd_nasid,
453 0 /*ignored */ ,
454 SAL_IROUTER_INTR_RECV);
455
456 /* on the console nasid, prepare to receive
457 * system controller environmental events
458 */
459 if(scd->scd_nasid == event_nasid) {
460 scdrv_event_init(scd);
461 }
462 }
463 return 0;
464}
465
466module_init(scdrv_init);