Merge tag 'cleanup' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
[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, 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
37 static DEFINE_MUTEX(scdrv_mutex);
38 static irqreturn_t
39 scdrv_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
71 static int
72 scdrv_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
130 static int
131 scdrv_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
153 static inline int
154 read_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
159 static ssize_t
160 scdrv_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  */
245 static inline int
246 write_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
251 static ssize_t
252 scdrv_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
325 static unsigned int
326 scdrv_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
354 static 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
364 static struct class *snsc_class;
365
366 /*
367  * scdrv_init
368  *
369  * Called at boot time to initialize the system controller communication
370  * facility.
371  */
372 int __init
373 scdrv_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
466 module_init(scdrv_init);