Merge branch 'for-jeff' of git://git.kernel.org/pub/scm/linux/kernel/git/chris/linux...
[linux-2.6] / 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, 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/smp_lock.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
37 static irqreturn_t
38 scdrv_interrupt(int irq, void *subch_data)
39 {
40         struct subch_data_s *sd = subch_data;
41         unsigned long flags;
42         int status;
43
44         spin_lock_irqsave(&sd->sd_rlock, flags);
45         spin_lock(&sd->sd_wlock);
46         status = ia64_sn_irtr_intr(sd->sd_nasid, sd->sd_subch);
47
48         if (status > 0) {
49                 if (status & SAL_IROUTER_INTR_RECV) {
50                         wake_up(&sd->sd_rq);
51                 }
52                 if (status & SAL_IROUTER_INTR_XMIT) {
53                         ia64_sn_irtr_intr_disable
54                             (sd->sd_nasid, sd->sd_subch,
55                              SAL_IROUTER_INTR_XMIT);
56                         wake_up(&sd->sd_wq);
57                 }
58         }
59         spin_unlock(&sd->sd_wlock);
60         spin_unlock_irqrestore(&sd->sd_rlock, flags);
61         return IRQ_HANDLED;
62 }
63
64 /*
65  * scdrv_open
66  *
67  * Reserve a subchannel for system controller communication.
68  */
69
70 static int
71 scdrv_open(struct inode *inode, struct file *file)
72 {
73         struct sysctl_data_s *scd;
74         struct subch_data_s *sd;
75         int rv;
76
77         /* look up device info for this device file */
78         scd = container_of(inode->i_cdev, struct sysctl_data_s, scd_cdev);
79
80         /* allocate memory for subchannel data */
81         sd = kzalloc(sizeof (struct subch_data_s), GFP_KERNEL);
82         if (sd == NULL) {
83                 printk("%s: couldn't allocate subchannel data\n",
84                        __func__);
85                 return -ENOMEM;
86         }
87
88         /* initialize subch_data_s fields */
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", __func__);
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         lock_kernel();
109         rv = request_irq(SGI_UART_VECTOR, scdrv_interrupt,
110                          IRQF_SHARED | IRQF_DISABLED,
111                          SYSCTL_BASENAME, sd);
112         if (rv) {
113                 ia64_sn_irtr_close(sd->sd_nasid, sd->sd_subch);
114                 kfree(sd);
115                 printk("%s: irq request failed (%d)\n", __func__, rv);
116                 unlock_kernel();
117                 return -EBUSY;
118         }
119         unlock_kernel();
120         return 0;
121 }
122
123 /*
124  * scdrv_release
125  *
126  * Release a previously-reserved subchannel.
127  */
128
129 static int
130 scdrv_release(struct inode *inode, struct file *file)
131 {
132         struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
133         int rv;
134
135         /* free the interrupt */
136         free_irq(SGI_UART_VECTOR, sd);
137
138         /* ask SAL to close the subchannel */
139         rv = ia64_sn_irtr_close(sd->sd_nasid, sd->sd_subch);
140
141         kfree(sd);
142         return rv;
143 }
144
145 /*
146  * scdrv_read
147  *
148  * Called to read bytes from the open IRouter pipe.
149  *
150  */
151
152 static inline int
153 read_status_check(struct subch_data_s *sd, int *len)
154 {
155         return ia64_sn_irtr_recv(sd->sd_nasid, sd->sd_subch, sd->sd_rb, len);
156 }
157
158 static ssize_t
159 scdrv_read(struct file *file, char __user *buf, size_t count, loff_t *f_pos)
160 {
161         int status;
162         int len;
163         unsigned long flags;
164         struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
165
166         /* try to get control of the read buffer */
167         if (down_trylock(&sd->sd_rbs)) {
168                 /* somebody else has it now;
169                  * if we're non-blocking, then exit...
170                  */
171                 if (file->f_flags & O_NONBLOCK) {
172                         return -EAGAIN;
173                 }
174                 /* ...or if we want to block, then do so here */
175                 if (down_interruptible(&sd->sd_rbs)) {
176                         /* something went wrong with wait */
177                         return -ERESTARTSYS;
178                 }
179         }
180
181         /* anything to read? */
182         len = CHUNKSIZE;
183         spin_lock_irqsave(&sd->sd_rlock, flags);
184         status = read_status_check(sd, &len);
185
186         /* if not, and we're blocking I/O, loop */
187         while (status < 0) {
188                 DECLARE_WAITQUEUE(wait, current);
189
190                 if (file->f_flags & O_NONBLOCK) {
191                         spin_unlock_irqrestore(&sd->sd_rlock, flags);
192                         up(&sd->sd_rbs);
193                         return -EAGAIN;
194                 }
195
196                 len = CHUNKSIZE;
197                 set_current_state(TASK_INTERRUPTIBLE);
198                 add_wait_queue(&sd->sd_rq, &wait);
199                 spin_unlock_irqrestore(&sd->sd_rlock, flags);
200
201                 schedule_timeout(SCDRV_TIMEOUT);
202
203                 remove_wait_queue(&sd->sd_rq, &wait);
204                 if (signal_pending(current)) {
205                         /* wait was interrupted */
206                         up(&sd->sd_rbs);
207                         return -ERESTARTSYS;
208                 }
209
210                 spin_lock_irqsave(&sd->sd_rlock, flags);
211                 status = read_status_check(sd, &len);
212         }
213         spin_unlock_irqrestore(&sd->sd_rlock, flags);
214
215         if (len > 0) {
216                 /* we read something in the last read_status_check(); copy
217                  * it out to user space
218                  */
219                 if (count < len) {
220                         pr_debug("%s: only accepting %d of %d bytes\n",
221                                  __func__, (int) count, len);
222                 }
223                 len = min((int) count, len);
224                 if (copy_to_user(buf, sd->sd_rb, len))
225                         len = -EFAULT;
226         }
227
228         /* release the read buffer and wake anyone who might be
229          * waiting for it
230          */
231         up(&sd->sd_rbs);
232
233         /* return the number of characters read in */
234         return len;
235 }
236
237 /*
238  * scdrv_write
239  *
240  * Writes a chunk of an IRouter packet (or other system controller data)
241  * to the system controller.
242  *
243  */
244 static inline int
245 write_status_check(struct subch_data_s *sd, int count)
246 {
247         return ia64_sn_irtr_send(sd->sd_nasid, sd->sd_subch, sd->sd_wb, count);
248 }
249
250 static ssize_t
251 scdrv_write(struct file *file, const char __user *buf,
252             size_t count, loff_t *f_pos)
253 {
254         unsigned long flags;
255         int status;
256         struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
257
258         /* try to get control of the write buffer */
259         if (down_trylock(&sd->sd_wbs)) {
260                 /* somebody else has it now;
261                  * if we're non-blocking, then exit...
262                  */
263                 if (file->f_flags & O_NONBLOCK) {
264                         return -EAGAIN;
265                 }
266                 /* ...or if we want to block, then do so here */
267                 if (down_interruptible(&sd->sd_wbs)) {
268                         /* something went wrong with wait */
269                         return -ERESTARTSYS;
270                 }
271         }
272
273         count = min((int) count, CHUNKSIZE);
274         if (copy_from_user(sd->sd_wb, buf, count)) {
275                 up(&sd->sd_wbs);
276                 return -EFAULT;
277         }
278
279         /* try to send the buffer */
280         spin_lock_irqsave(&sd->sd_wlock, flags);
281         status = write_status_check(sd, count);
282
283         /* if we failed, and we want to block, then loop */
284         while (status <= 0) {
285                 DECLARE_WAITQUEUE(wait, current);
286
287                 if (file->f_flags & O_NONBLOCK) {
288                         spin_unlock(&sd->sd_wlock);
289                         up(&sd->sd_wbs);
290                         return -EAGAIN;
291                 }
292
293                 set_current_state(TASK_INTERRUPTIBLE);
294                 add_wait_queue(&sd->sd_wq, &wait);
295                 spin_unlock_irqrestore(&sd->sd_wlock, flags);
296
297                 schedule_timeout(SCDRV_TIMEOUT);
298
299                 remove_wait_queue(&sd->sd_wq, &wait);
300                 if (signal_pending(current)) {
301                         /* wait was interrupted */
302                         up(&sd->sd_wbs);
303                         return -ERESTARTSYS;
304                 }
305
306                 spin_lock_irqsave(&sd->sd_wlock, flags);
307                 status = write_status_check(sd, count);
308         }
309         spin_unlock_irqrestore(&sd->sd_wlock, flags);
310
311         /* release the write buffer and wake anyone who's waiting for it */
312         up(&sd->sd_wbs);
313
314         /* return the number of characters accepted (should be the complete
315          * "chunk" as requested)
316          */
317         if ((status >= 0) && (status < count)) {
318                 pr_debug("Didn't accept the full chunk; %d of %d\n",
319                          status, (int) count);
320         }
321         return status;
322 }
323
324 static unsigned int
325 scdrv_poll(struct file *file, struct poll_table_struct *wait)
326 {
327         unsigned int mask = 0;
328         int status = 0;
329         struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
330         unsigned long flags;
331
332         poll_wait(file, &sd->sd_rq, wait);
333         poll_wait(file, &sd->sd_wq, wait);
334
335         spin_lock_irqsave(&sd->sd_rlock, flags);
336         spin_lock(&sd->sd_wlock);
337         status = ia64_sn_irtr_intr(sd->sd_nasid, sd->sd_subch);
338         spin_unlock(&sd->sd_wlock);
339         spin_unlock_irqrestore(&sd->sd_rlock, flags);
340
341         if (status > 0) {
342                 if (status & SAL_IROUTER_INTR_RECV) {
343                         mask |= POLLIN | POLLRDNORM;
344                 }
345                 if (status & SAL_IROUTER_INTR_XMIT) {
346                         mask |= POLLOUT | POLLWRNORM;
347                 }
348         }
349
350         return mask;
351 }
352
353 static const struct file_operations scdrv_fops = {
354         .owner =        THIS_MODULE,
355         .read =         scdrv_read,
356         .write =        scdrv_write,
357         .poll =         scdrv_poll,
358         .open =         scdrv_open,
359         .release =      scdrv_release,
360 };
361
362 static struct class *snsc_class;
363
364 /*
365  * scdrv_init
366  *
367  * Called at boot time to initialize the system controller communication
368  * facility.
369  */
370 int __init
371 scdrv_init(void)
372 {
373         geoid_t geoid;
374         cnodeid_t cnode;
375         char devname[32];
376         char *devnamep;
377         struct sysctl_data_s *scd;
378         void *salbuf;
379         dev_t first_dev, dev;
380         nasid_t event_nasid;
381
382         if (!ia64_platform_is("sn2"))
383                 return -ENODEV;
384
385         event_nasid = ia64_sn_get_console_nasid();
386
387         if (alloc_chrdev_region(&first_dev, 0, num_cnodes,
388                                 SYSCTL_BASENAME) < 0) {
389                 printk("%s: failed to register SN system controller device\n",
390                        __func__);
391                 return -ENODEV;
392         }
393         snsc_class = class_create(THIS_MODULE, SYSCTL_BASENAME);
394
395         for (cnode = 0; cnode < num_cnodes; cnode++) {
396                         geoid = cnodeid_get_geoid(cnode);
397                         devnamep = devname;
398                         format_module_id(devnamep, geo_module(geoid),
399                                          MODULE_FORMAT_BRIEF);
400                         devnamep = devname + strlen(devname);
401                         sprintf(devnamep, "^%d#%d", geo_slot(geoid),
402                                 geo_slab(geoid));
403
404                         /* allocate sysctl device data */
405                         scd = kzalloc(sizeof (struct sysctl_data_s),
406                                       GFP_KERNEL);
407                         if (!scd) {
408                                 printk("%s: failed to allocate device info"
409                                        "for %s/%s\n", __func__,
410                                        SYSCTL_BASENAME, devname);
411                                 continue;
412                         }
413
414                         /* initialize sysctl device data fields */
415                         scd->scd_nasid = cnodeid_to_nasid(cnode);
416                         if (!(salbuf = kmalloc(SCDRV_BUFSZ, GFP_KERNEL))) {
417                                 printk("%s: failed to allocate driver buffer"
418                                        "(%s%s)\n", __func__,
419                                        SYSCTL_BASENAME, devname);
420                                 kfree(scd);
421                                 continue;
422                         }
423
424                         if (ia64_sn_irtr_init(scd->scd_nasid, salbuf,
425                                               SCDRV_BUFSZ) < 0) {
426                                 printk
427                                     ("%s: failed to initialize SAL for"
428                                      " system controller communication"
429                                      " (%s/%s): outdated PROM?\n",
430                                      __func__, SYSCTL_BASENAME, devname);
431                                 kfree(scd);
432                                 kfree(salbuf);
433                                 continue;
434                         }
435
436                         dev = first_dev + cnode;
437                         cdev_init(&scd->scd_cdev, &scdrv_fops);
438                         if (cdev_add(&scd->scd_cdev, dev, 1)) {
439                                 printk("%s: failed to register system"
440                                        " controller device (%s%s)\n",
441                                        __func__, SYSCTL_BASENAME, devname);
442                                 kfree(scd);
443                                 kfree(salbuf);
444                                 continue;
445                         }
446
447                         device_create_drvdata(snsc_class, NULL, dev, NULL,
448                                               "%s", devname);
449
450                         ia64_sn_irtr_intr_enable(scd->scd_nasid,
451                                                  0 /*ignored */ ,
452                                                  SAL_IROUTER_INTR_RECV);
453
454                         /* on the console nasid, prepare to receive
455                          * system controller environmental events
456                          */
457                         if(scd->scd_nasid == event_nasid) {
458                                 scdrv_event_init(scd);
459                         }
460         }
461         return 0;
462 }
463
464 module_init(scdrv_init);