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);