ia64/linux-2.6.18-xen.hg

view drivers/char/snsc.c @ 893:f994bfe9b93b

linux/blktap2: reduce TLB flush scope

c/s 885 added very coarse TLB flushing. Since these flushes always
follow single page updates, single page flushes (when available) are
sufficient.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
author Keir Fraser <keir.fraser@citrix.com>
date Thu Jun 04 10:32:57 2009 +0100 (2009-06-04)
parents 831230e53067
children
line source
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 */
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 */
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 <asm/sn/io.h>
25 #include <asm/sn/sn_sal.h>
26 #include <asm/sn/module.h>
27 #include <asm/sn/geo.h>
28 #include <asm/sn/nodepda.h>
29 #include "snsc.h"
31 #define SYSCTL_BASENAME "snsc"
33 #define SCDRV_BUFSZ 2048
34 #define SCDRV_TIMEOUT 1000
36 static irqreturn_t
37 scdrv_interrupt(int irq, void *subch_data, struct pt_regs *regs)
38 {
39 struct subch_data_s *sd = subch_data;
40 unsigned long flags;
41 int status;
43 spin_lock_irqsave(&sd->sd_rlock, flags);
44 spin_lock(&sd->sd_wlock);
45 status = ia64_sn_irtr_intr(sd->sd_nasid, sd->sd_subch);
47 if (status > 0) {
48 if (status & SAL_IROUTER_INTR_RECV) {
49 wake_up(&sd->sd_rq);
50 }
51 if (status & SAL_IROUTER_INTR_XMIT) {
52 ia64_sn_irtr_intr_disable
53 (sd->sd_nasid, sd->sd_subch,
54 SAL_IROUTER_INTR_XMIT);
55 wake_up(&sd->sd_wq);
56 }
57 }
58 spin_unlock(&sd->sd_wlock);
59 spin_unlock_irqrestore(&sd->sd_rlock, flags);
60 return IRQ_HANDLED;
61 }
63 /*
64 * scdrv_open
65 *
66 * Reserve a subchannel for system controller communication.
67 */
69 static int
70 scdrv_open(struct inode *inode, struct file *file)
71 {
72 struct sysctl_data_s *scd;
73 struct subch_data_s *sd;
74 int rv;
76 /* look up device info for this device file */
77 scd = container_of(inode->i_cdev, struct sysctl_data_s, scd_cdev);
79 /* allocate memory for subchannel data */
80 sd = kzalloc(sizeof (struct subch_data_s), GFP_KERNEL);
81 if (sd == NULL) {
82 printk("%s: couldn't allocate subchannel data\n",
83 __FUNCTION__);
84 return -ENOMEM;
85 }
87 /* initialize subch_data_s fields */
88 sd->sd_nasid = scd->scd_nasid;
89 sd->sd_subch = ia64_sn_irtr_open(scd->scd_nasid);
91 if (sd->sd_subch < 0) {
92 kfree(sd);
93 printk("%s: couldn't allocate subchannel\n", __FUNCTION__);
94 return -EBUSY;
95 }
97 spin_lock_init(&sd->sd_rlock);
98 spin_lock_init(&sd->sd_wlock);
99 init_waitqueue_head(&sd->sd_rq);
100 init_waitqueue_head(&sd->sd_wq);
101 sema_init(&sd->sd_rbs, 1);
102 sema_init(&sd->sd_wbs, 1);
104 file->private_data = sd;
106 /* hook this subchannel up to the system controller interrupt */
107 rv = request_irq(SGI_UART_VECTOR, scdrv_interrupt,
108 IRQF_SHARED | IRQF_DISABLED,
109 SYSCTL_BASENAME, sd);
110 if (rv) {
111 ia64_sn_irtr_close(sd->sd_nasid, sd->sd_subch);
112 kfree(sd);
113 printk("%s: irq request failed (%d)\n", __FUNCTION__, rv);
114 return -EBUSY;
115 }
117 return 0;
118 }
120 /*
121 * scdrv_release
122 *
123 * Release a previously-reserved subchannel.
124 */
126 static int
127 scdrv_release(struct inode *inode, struct file *file)
128 {
129 struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
130 int rv;
132 /* free the interrupt */
133 free_irq(SGI_UART_VECTOR, sd);
135 /* ask SAL to close the subchannel */
136 rv = ia64_sn_irtr_close(sd->sd_nasid, sd->sd_subch);
138 kfree(sd);
139 return rv;
140 }
142 /*
143 * scdrv_read
144 *
145 * Called to read bytes from the open IRouter pipe.
146 *
147 */
149 static inline int
150 read_status_check(struct subch_data_s *sd, int *len)
151 {
152 return ia64_sn_irtr_recv(sd->sd_nasid, sd->sd_subch, sd->sd_rb, len);
153 }
155 static ssize_t
156 scdrv_read(struct file *file, char __user *buf, size_t count, loff_t *f_pos)
157 {
158 int status;
159 int len;
160 unsigned long flags;
161 struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
163 /* try to get control of the read buffer */
164 if (down_trylock(&sd->sd_rbs)) {
165 /* somebody else has it now;
166 * if we're non-blocking, then exit...
167 */
168 if (file->f_flags & O_NONBLOCK) {
169 return -EAGAIN;
170 }
171 /* ...or if we want to block, then do so here */
172 if (down_interruptible(&sd->sd_rbs)) {
173 /* something went wrong with wait */
174 return -ERESTARTSYS;
175 }
176 }
178 /* anything to read? */
179 len = CHUNKSIZE;
180 spin_lock_irqsave(&sd->sd_rlock, flags);
181 status = read_status_check(sd, &len);
183 /* if not, and we're blocking I/O, loop */
184 while (status < 0) {
185 DECLARE_WAITQUEUE(wait, current);
187 if (file->f_flags & O_NONBLOCK) {
188 spin_unlock_irqrestore(&sd->sd_rlock, flags);
189 up(&sd->sd_rbs);
190 return -EAGAIN;
191 }
193 len = CHUNKSIZE;
194 set_current_state(TASK_INTERRUPTIBLE);
195 add_wait_queue(&sd->sd_rq, &wait);
196 spin_unlock_irqrestore(&sd->sd_rlock, flags);
198 schedule_timeout(SCDRV_TIMEOUT);
200 remove_wait_queue(&sd->sd_rq, &wait);
201 if (signal_pending(current)) {
202 /* wait was interrupted */
203 up(&sd->sd_rbs);
204 return -ERESTARTSYS;
205 }
207 spin_lock_irqsave(&sd->sd_rlock, flags);
208 status = read_status_check(sd, &len);
209 }
210 spin_unlock_irqrestore(&sd->sd_rlock, flags);
212 if (len > 0) {
213 /* we read something in the last read_status_check(); copy
214 * it out to user space
215 */
216 if (count < len) {
217 pr_debug("%s: only accepting %d of %d bytes\n",
218 __FUNCTION__, (int) count, len);
219 }
220 len = min((int) count, len);
221 if (copy_to_user(buf, sd->sd_rb, len))
222 len = -EFAULT;
223 }
225 /* release the read buffer and wake anyone who might be
226 * waiting for it
227 */
228 up(&sd->sd_rbs);
230 /* return the number of characters read in */
231 return len;
232 }
234 /*
235 * scdrv_write
236 *
237 * Writes a chunk of an IRouter packet (or other system controller data)
238 * to the system controller.
239 *
240 */
241 static inline int
242 write_status_check(struct subch_data_s *sd, int count)
243 {
244 return ia64_sn_irtr_send(sd->sd_nasid, sd->sd_subch, sd->sd_wb, count);
245 }
247 static ssize_t
248 scdrv_write(struct file *file, const char __user *buf,
249 size_t count, loff_t *f_pos)
250 {
251 unsigned long flags;
252 int status;
253 struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
255 /* try to get control of the write buffer */
256 if (down_trylock(&sd->sd_wbs)) {
257 /* somebody else has it now;
258 * if we're non-blocking, then exit...
259 */
260 if (file->f_flags & O_NONBLOCK) {
261 return -EAGAIN;
262 }
263 /* ...or if we want to block, then do so here */
264 if (down_interruptible(&sd->sd_wbs)) {
265 /* something went wrong with wait */
266 return -ERESTARTSYS;
267 }
268 }
270 count = min((int) count, CHUNKSIZE);
271 if (copy_from_user(sd->sd_wb, buf, count)) {
272 up(&sd->sd_wbs);
273 return -EFAULT;
274 }
276 /* try to send the buffer */
277 spin_lock_irqsave(&sd->sd_wlock, flags);
278 status = write_status_check(sd, count);
280 /* if we failed, and we want to block, then loop */
281 while (status <= 0) {
282 DECLARE_WAITQUEUE(wait, current);
284 if (file->f_flags & O_NONBLOCK) {
285 spin_unlock(&sd->sd_wlock);
286 up(&sd->sd_wbs);
287 return -EAGAIN;
288 }
290 set_current_state(TASK_INTERRUPTIBLE);
291 add_wait_queue(&sd->sd_wq, &wait);
292 spin_unlock_irqrestore(&sd->sd_wlock, flags);
294 schedule_timeout(SCDRV_TIMEOUT);
296 remove_wait_queue(&sd->sd_wq, &wait);
297 if (signal_pending(current)) {
298 /* wait was interrupted */
299 up(&sd->sd_wbs);
300 return -ERESTARTSYS;
301 }
303 spin_lock_irqsave(&sd->sd_wlock, flags);
304 status = write_status_check(sd, count);
305 }
306 spin_unlock_irqrestore(&sd->sd_wlock, flags);
308 /* release the write buffer and wake anyone who's waiting for it */
309 up(&sd->sd_wbs);
311 /* return the number of characters accepted (should be the complete
312 * "chunk" as requested)
313 */
314 if ((status >= 0) && (status < count)) {
315 pr_debug("Didn't accept the full chunk; %d of %d\n",
316 status, (int) count);
317 }
318 return status;
319 }
321 static unsigned int
322 scdrv_poll(struct file *file, struct poll_table_struct *wait)
323 {
324 unsigned int mask = 0;
325 int status = 0;
326 struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
327 unsigned long flags;
329 poll_wait(file, &sd->sd_rq, wait);
330 poll_wait(file, &sd->sd_wq, wait);
332 spin_lock_irqsave(&sd->sd_rlock, flags);
333 spin_lock(&sd->sd_wlock);
334 status = ia64_sn_irtr_intr(sd->sd_nasid, sd->sd_subch);
335 spin_unlock(&sd->sd_wlock);
336 spin_unlock_irqrestore(&sd->sd_rlock, flags);
338 if (status > 0) {
339 if (status & SAL_IROUTER_INTR_RECV) {
340 mask |= POLLIN | POLLRDNORM;
341 }
342 if (status & SAL_IROUTER_INTR_XMIT) {
343 mask |= POLLOUT | POLLWRNORM;
344 }
345 }
347 return mask;
348 }
350 static const struct file_operations scdrv_fops = {
351 .owner = THIS_MODULE,
352 .read = scdrv_read,
353 .write = scdrv_write,
354 .poll = scdrv_poll,
355 .open = scdrv_open,
356 .release = scdrv_release,
357 };
359 static struct class *snsc_class;
361 /*
362 * scdrv_init
363 *
364 * Called at boot time to initialize the system controller communication
365 * facility.
366 */
367 int __init
368 scdrv_init(void)
369 {
370 geoid_t geoid;
371 cnodeid_t cnode;
372 char devname[32];
373 char *devnamep;
374 struct sysctl_data_s *scd;
375 void *salbuf;
376 dev_t first_dev, dev;
377 nasid_t event_nasid;
379 if (!ia64_platform_is("sn2"))
380 return -ENODEV;
382 event_nasid = ia64_sn_get_console_nasid();
384 if (alloc_chrdev_region(&first_dev, 0, num_cnodes,
385 SYSCTL_BASENAME) < 0) {
386 printk("%s: failed to register SN system controller device\n",
387 __FUNCTION__);
388 return -ENODEV;
389 }
390 snsc_class = class_create(THIS_MODULE, SYSCTL_BASENAME);
392 for (cnode = 0; cnode < num_cnodes; cnode++) {
393 geoid = cnodeid_get_geoid(cnode);
394 devnamep = devname;
395 format_module_id(devnamep, geo_module(geoid),
396 MODULE_FORMAT_BRIEF);
397 devnamep = devname + strlen(devname);
398 sprintf(devnamep, "^%d#%d", geo_slot(geoid),
399 geo_slab(geoid));
401 /* allocate sysctl device data */
402 scd = kzalloc(sizeof (struct sysctl_data_s),
403 GFP_KERNEL);
404 if (!scd) {
405 printk("%s: failed to allocate device info"
406 "for %s/%s\n", __FUNCTION__,
407 SYSCTL_BASENAME, devname);
408 continue;
409 }
411 /* initialize sysctl device data fields */
412 scd->scd_nasid = cnodeid_to_nasid(cnode);
413 if (!(salbuf = kmalloc(SCDRV_BUFSZ, GFP_KERNEL))) {
414 printk("%s: failed to allocate driver buffer"
415 "(%s%s)\n", __FUNCTION__,
416 SYSCTL_BASENAME, devname);
417 kfree(scd);
418 continue;
419 }
421 if (ia64_sn_irtr_init(scd->scd_nasid, salbuf,
422 SCDRV_BUFSZ) < 0) {
423 printk
424 ("%s: failed to initialize SAL for"
425 " system controller communication"
426 " (%s/%s): outdated PROM?\n",
427 __FUNCTION__, SYSCTL_BASENAME, devname);
428 kfree(scd);
429 kfree(salbuf);
430 continue;
431 }
433 dev = first_dev + cnode;
434 cdev_init(&scd->scd_cdev, &scdrv_fops);
435 if (cdev_add(&scd->scd_cdev, dev, 1)) {
436 printk("%s: failed to register system"
437 " controller device (%s%s)\n",
438 __FUNCTION__, SYSCTL_BASENAME, devname);
439 kfree(scd);
440 kfree(salbuf);
441 continue;
442 }
444 class_device_create(snsc_class, NULL, dev, NULL,
445 "%s", devname);
447 ia64_sn_irtr_intr_enable(scd->scd_nasid,
448 0 /*ignored */ ,
449 SAL_IROUTER_INTR_RECV);
451 /* on the console nasid, prepare to receive
452 * system controller environmental events
453 */
454 if(scd->scd_nasid == event_nasid) {
455 scdrv_event_init(scd);
456 }
457 }
458 return 0;
459 }
461 module_init(scdrv_init);