Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6
[linux-2.6.git] / drivers / char / snsc.c
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 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 <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"
30
31 #define SYSCTL_BASENAME "snsc"
32
33 #define SCDRV_BUFSZ     2048
34 #define SCDRV_TIMEOUT   1000
35
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;
42
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);
46
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 }
62
63 /*
64  * scdrv_open
65  *
66  * Reserve a subchannel for system controller communication.
67  */
68
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;
75
76         /* look up device info for this device file */
77         scd = container_of(inode->i_cdev, struct sysctl_data_s, scd_cdev);
78
79         /* allocate memory for subchannel data */
80         sd = kmalloc(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         }
86
87         /* initialize subch_data_s fields */
88         memset(sd, 0, sizeof (struct subch_data_s));
89         sd->sd_nasid = scd->scd_nasid;
90         sd->sd_subch = ia64_sn_irtr_open(scd->scd_nasid);
91
92         if (sd->sd_subch < 0) {
93                 kfree(sd);
94                 printk("%s: couldn't allocate subchannel\n", __FUNCTION__);
95                 return -EBUSY;
96         }
97
98         spin_lock_init(&sd->sd_rlock);
99         spin_lock_init(&sd->sd_wlock);
100         init_waitqueue_head(&sd->sd_rq);
101         init_waitqueue_head(&sd->sd_wq);
102         sema_init(&sd->sd_rbs, 1);
103         sema_init(&sd->sd_wbs, 1);
104
105         file->private_data = sd;
106
107         /* hook this subchannel up to the system controller interrupt */
108         rv = request_irq(SGI_UART_VECTOR, scdrv_interrupt,
109                          SA_SHIRQ | SA_INTERRUPT,
110                          SYSCTL_BASENAME, sd);
111         if (rv) {
112                 ia64_sn_irtr_close(sd->sd_nasid, sd->sd_subch);
113                 kfree(sd);
114                 printk("%s: irq request failed (%d)\n", __FUNCTION__, rv);
115                 return -EBUSY;
116         }
117
118         return 0;
119 }
120
121 /*
122  * scdrv_release
123  *
124  * Release a previously-reserved subchannel.
125  */
126
127 static int
128 scdrv_release(struct inode *inode, struct file *file)
129 {
130         struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
131         int rv;
132
133         /* free the interrupt */
134         free_irq(SGI_UART_VECTOR, sd);
135
136         /* ask SAL to close the subchannel */
137         rv = ia64_sn_irtr_close(sd->sd_nasid, sd->sd_subch);
138
139         kfree(sd);
140         return rv;
141 }
142
143 /*
144  * scdrv_read
145  *
146  * Called to read bytes from the open IRouter pipe.
147  *
148  */
149
150 static inline int
151 read_status_check(struct subch_data_s *sd, int *len)
152 {
153         return ia64_sn_irtr_recv(sd->sd_nasid, sd->sd_subch, sd->sd_rb, len);
154 }
155
156 static ssize_t
157 scdrv_read(struct file *file, char __user *buf, size_t count, loff_t *f_pos)
158 {
159         int status;
160         int len;
161         unsigned long flags;
162         struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
163
164         /* try to get control of the read buffer */
165         if (down_trylock(&sd->sd_rbs)) {
166                 /* somebody else has it now;
167                  * if we're non-blocking, then exit...
168                  */
169                 if (file->f_flags & O_NONBLOCK) {
170                         return -EAGAIN;
171                 }
172                 /* ...or if we want to block, then do so here */
173                 if (down_interruptible(&sd->sd_rbs)) {
174                         /* something went wrong with wait */
175                         return -ERESTARTSYS;
176                 }
177         }
178
179         /* anything to read? */
180         len = CHUNKSIZE;
181         spin_lock_irqsave(&sd->sd_rlock, flags);
182         status = read_status_check(sd, &len);
183
184         /* if not, and we're blocking I/O, loop */
185         while (status < 0) {
186                 DECLARE_WAITQUEUE(wait, current);
187
188                 if (file->f_flags & O_NONBLOCK) {
189                         spin_unlock_irqrestore(&sd->sd_rlock, flags);
190                         up(&sd->sd_rbs);
191                         return -EAGAIN;
192                 }
193
194                 len = CHUNKSIZE;
195                 set_current_state(TASK_INTERRUPTIBLE);
196                 add_wait_queue(&sd->sd_rq, &wait);
197                 spin_unlock_irqrestore(&sd->sd_rlock, flags);
198
199                 schedule_timeout(SCDRV_TIMEOUT);
200
201                 remove_wait_queue(&sd->sd_rq, &wait);
202                 if (signal_pending(current)) {
203                         /* wait was interrupted */
204                         up(&sd->sd_rbs);
205                         return -ERESTARTSYS;
206                 }
207
208                 spin_lock_irqsave(&sd->sd_rlock, flags);
209                 status = read_status_check(sd, &len);
210         }
211         spin_unlock_irqrestore(&sd->sd_rlock, flags);
212
213         if (len > 0) {
214                 /* we read something in the last read_status_check(); copy
215                  * it out to user space
216                  */
217                 if (count < len) {
218                         pr_debug("%s: only accepting %d of %d bytes\n",
219                                  __FUNCTION__, (int) count, len);
220                 }
221                 len = min((int) count, len);
222                 if (copy_to_user(buf, sd->sd_rb, len))
223                         len = -EFAULT;
224         }
225
226         /* release the read buffer and wake anyone who might be
227          * waiting for it
228          */
229         up(&sd->sd_rbs);
230
231         /* return the number of characters read in */
232         return len;
233 }
234
235 /*
236  * scdrv_write
237  *
238  * Writes a chunk of an IRouter packet (or other system controller data)
239  * to the system controller.
240  *
241  */
242 static inline int
243 write_status_check(struct subch_data_s *sd, int count)
244 {
245         return ia64_sn_irtr_send(sd->sd_nasid, sd->sd_subch, sd->sd_wb, count);
246 }
247
248 static ssize_t
249 scdrv_write(struct file *file, const char __user *buf,
250             size_t count, loff_t *f_pos)
251 {
252         unsigned long flags;
253         int status;
254         struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
255
256         /* try to get control of the write buffer */
257         if (down_trylock(&sd->sd_wbs)) {
258                 /* somebody else has it now;
259                  * if we're non-blocking, then exit...
260                  */
261                 if (file->f_flags & O_NONBLOCK) {
262                         return -EAGAIN;
263                 }
264                 /* ...or if we want to block, then do so here */
265                 if (down_interruptible(&sd->sd_wbs)) {
266                         /* something went wrong with wait */
267                         return -ERESTARTSYS;
268                 }
269         }
270
271         count = min((int) count, CHUNKSIZE);
272         if (copy_from_user(sd->sd_wb, buf, count)) {
273                 up(&sd->sd_wbs);
274                 return -EFAULT;
275         }
276
277         /* try to send the buffer */
278         spin_lock_irqsave(&sd->sd_wlock, flags);
279         status = write_status_check(sd, count);
280
281         /* if we failed, and we want to block, then loop */
282         while (status <= 0) {
283                 DECLARE_WAITQUEUE(wait, current);
284
285                 if (file->f_flags & O_NONBLOCK) {
286                         spin_unlock(&sd->sd_wlock);
287                         up(&sd->sd_wbs);
288                         return -EAGAIN;
289                 }
290
291                 set_current_state(TASK_INTERRUPTIBLE);
292                 add_wait_queue(&sd->sd_wq, &wait);
293                 spin_unlock_irqrestore(&sd->sd_wlock, flags);
294
295                 schedule_timeout(SCDRV_TIMEOUT);
296
297                 remove_wait_queue(&sd->sd_wq, &wait);
298                 if (signal_pending(current)) {
299                         /* wait was interrupted */
300                         up(&sd->sd_wbs);
301                         return -ERESTARTSYS;
302                 }
303
304                 spin_lock_irqsave(&sd->sd_wlock, flags);
305                 status = write_status_check(sd, count);
306         }
307         spin_unlock_irqrestore(&sd->sd_wlock, flags);
308
309         /* release the write buffer and wake anyone who's waiting for it */
310         up(&sd->sd_wbs);
311
312         /* return the number of characters accepted (should be the complete
313          * "chunk" as requested)
314          */
315         if ((status >= 0) && (status < count)) {
316                 pr_debug("Didn't accept the full chunk; %d of %d\n",
317                          status, (int) count);
318         }
319         return status;
320 }
321
322 static unsigned int
323 scdrv_poll(struct file *file, struct poll_table_struct *wait)
324 {
325         unsigned int mask = 0;
326         int status = 0;
327         struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
328         unsigned long flags;
329
330         poll_wait(file, &sd->sd_rq, wait);
331         poll_wait(file, &sd->sd_wq, wait);
332
333         spin_lock_irqsave(&sd->sd_rlock, flags);
334         spin_lock(&sd->sd_wlock);
335         status = ia64_sn_irtr_intr(sd->sd_nasid, sd->sd_subch);
336         spin_unlock(&sd->sd_wlock);
337         spin_unlock_irqrestore(&sd->sd_rlock, flags);
338
339         if (status > 0) {
340                 if (status & SAL_IROUTER_INTR_RECV) {
341                         mask |= POLLIN | POLLRDNORM;
342                 }
343                 if (status & SAL_IROUTER_INTR_XMIT) {
344                         mask |= POLLOUT | POLLWRNORM;
345                 }
346         }
347
348         return mask;
349 }
350
351 static struct file_operations scdrv_fops = {
352         .owner =        THIS_MODULE,
353         .read =         scdrv_read,
354         .write =        scdrv_write,
355         .poll =         scdrv_poll,
356         .open =         scdrv_open,
357         .release =      scdrv_release,
358 };
359
360 static struct class *snsc_class;
361
362 /*
363  * scdrv_init
364  *
365  * Called at boot time to initialize the system controller communication
366  * facility.
367  */
368 int __init
369 scdrv_init(void)
370 {
371         geoid_t geoid;
372         cnodeid_t cnode;
373         char devname[32];
374         char *devnamep;
375         struct sysctl_data_s *scd;
376         void *salbuf;
377         dev_t first_dev, dev;
378         nasid_t event_nasid = ia64_sn_get_console_nasid();
379
380         if (alloc_chrdev_region(&first_dev, 0, num_cnodes,
381                                 SYSCTL_BASENAME) < 0) {
382                 printk("%s: failed to register SN system controller device\n",
383                        __FUNCTION__);
384                 return -ENODEV;
385         }
386         snsc_class = class_create(THIS_MODULE, SYSCTL_BASENAME);
387
388         for (cnode = 0; cnode < num_cnodes; cnode++) {
389                         geoid = cnodeid_get_geoid(cnode);
390                         devnamep = devname;
391                         format_module_id(devnamep, geo_module(geoid),
392                                          MODULE_FORMAT_BRIEF);
393                         devnamep = devname + strlen(devname);
394                         sprintf(devnamep, "#%d", geo_slab(geoid));
395
396                         /* allocate sysctl device data */
397                         scd = kmalloc(sizeof (struct sysctl_data_s),
398                                       GFP_KERNEL);
399                         if (!scd) {
400                                 printk("%s: failed to allocate device info"
401                                        "for %s/%s\n", __FUNCTION__,
402                                        SYSCTL_BASENAME, devname);
403                                 continue;
404                         }
405                         memset(scd, 0, sizeof (struct sysctl_data_s));
406
407                         /* initialize sysctl device data fields */
408                         scd->scd_nasid = cnodeid_to_nasid(cnode);
409                         if (!(salbuf = kmalloc(SCDRV_BUFSZ, GFP_KERNEL))) {
410                                 printk("%s: failed to allocate driver buffer"
411                                        "(%s%s)\n", __FUNCTION__,
412                                        SYSCTL_BASENAME, devname);
413                                 kfree(scd);
414                                 continue;
415                         }
416
417                         if (ia64_sn_irtr_init(scd->scd_nasid, salbuf,
418                                               SCDRV_BUFSZ) < 0) {
419                                 printk
420                                     ("%s: failed to initialize SAL for"
421                                      " system controller communication"
422                                      " (%s/%s): outdated PROM?\n",
423                                      __FUNCTION__, SYSCTL_BASENAME, devname);
424                                 kfree(scd);
425                                 kfree(salbuf);
426                                 continue;
427                         }
428
429                         dev = first_dev + cnode;
430                         cdev_init(&scd->scd_cdev, &scdrv_fops);
431                         if (cdev_add(&scd->scd_cdev, dev, 1)) {
432                                 printk("%s: failed to register system"
433                                        " controller device (%s%s)\n",
434                                        __FUNCTION__, SYSCTL_BASENAME, devname);
435                                 kfree(scd);
436                                 kfree(salbuf);
437                                 continue;
438                         }
439
440                         class_device_create(snsc_class, NULL, dev, NULL,
441                                                 "%s", devname);
442
443                         ia64_sn_irtr_intr_enable(scd->scd_nasid,
444                                                  0 /*ignored */ ,
445                                                  SAL_IROUTER_INTR_RECV);
446
447                         /* on the console nasid, prepare to receive
448                          * system controller environmental events
449                          */
450                         if(scd->scd_nasid == event_nasid) {
451                                 scdrv_event_init(scd);
452                         }
453         }
454         return 0;
455 }
456
457 module_init(scdrv_init);