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/sn_sal.h>
  25 #include <asm/sn/nodepda.h>
  26 #include "snsc.h"
  27
  28 #define SYSCTL_BASENAME "snsc"
  29
  30 #define SCDRV_BUFSZ     2048
  31 #define SCDRV_TIMEOUT   1000
  32
  33 static irqreturn_t
  34 scdrv_interrupt(int irq, void *subch_data, struct pt_regs *regs)
  35 {
  36         struct subch_data_s *sd = subch_data;
  37         unsigned long flags;
  38         int status;
  39
  40         spin_lock_irqsave(&sd->sd_rlock, flags);
  41         spin_lock(&sd->sd_wlock);
  42         status = ia64_sn_irtr_intr(sd->sd_nasid, sd->sd_subch);
  43
  44         if (status > 0) {
  45                 if (status & SAL_IROUTER_INTR_RECV) {
  46                         wake_up(&sd->sd_rq);
  47                 }
  48                 if (status & SAL_IROUTER_INTR_XMIT) {
  49                         ia64_sn_irtr_intr_disable
  50                             (sd->sd_nasid, sd->sd_subch,
  51                              SAL_IROUTER_INTR_XMIT);
  52                         wake_up(&sd->sd_wq);
  53                 }
  54         }
  55         spin_unlock(&sd->sd_wlock);
  56         spin_unlock_irqrestore(&sd->sd_rlock, flags);
  57         return IRQ_HANDLED;
  58 }
  59
  60 /*
  61  * scdrv_open
  62  *
  63  * Reserve a subchannel for system controller communication.
  64  */
  65
  66 static int
  67 scdrv_open(struct inode *inode, struct file *file)
  68 {
  69         struct sysctl_data_s *scd;
  70         struct subch_data_s *sd;
  71         int rv;
  72
  73         /* look up device info for this device file */
  74         scd = container_of(inode->i_cdev, struct sysctl_data_s, scd_cdev);
  75
  76         /* allocate memory for subchannel data */
  77         sd = kmalloc(sizeof (struct subch_data_s), GFP_KERNEL);
  78         if (sd == NULL) {
  79                 printk("%s: couldn't allocate subchannel data\n",
  80                        __FUNCTION__);
  81                 return -ENOMEM;
  82         }
  83
  84         /* initialize subch_data_s fields */
  85         memset(sd, 0, sizeof (struct subch_data_s));
  86         sd->sd_nasid = scd->scd_nasid;
  87         sd->sd_subch = ia64_sn_irtr_open(scd->scd_nasid);
  88
  89         if (sd->sd_subch < 0) {
  90                 kfree(sd);
  91                 printk("%s: couldn't allocate subchannel\n", __FUNCTION__);
  92                 return -EBUSY;
  93         }
  94
  95         spin_lock_init(&sd->sd_rlock);
  96         spin_lock_init(&sd->sd_wlock);
  97         init_waitqueue_head(&sd->sd_rq);
  98         init_waitqueue_head(&sd->sd_wq);
  99         sema_init(&sd->sd_rbs, 1);
 100         sema_init(&sd->sd_wbs, 1);
 101
 102         file->private_data = sd;
 103
 104         /* hook this subchannel up to the system controller interrupt */
 105         rv = request_irq(SGI_UART_VECTOR, scdrv_interrupt,
 106                          SA_SHIRQ | SA_INTERRUPT,
 107                          SYSCTL_BASENAME, sd);
 108         if (rv) {
 109                 ia64_sn_irtr_close(sd->sd_nasid, sd->sd_subch);
 110                 kfree(sd);
 111                 printk("%s: irq request failed (%d)\n", __FUNCTION__, rv);
 112                 return -EBUSY;
 113         }
 114
 115         return 0;
 116 }
 117
 118 /*
 119  * scdrv_release
 120  *
 121  * Release a previously-reserved subchannel.
 122  */
 123
 124 static int
 125 scdrv_release(struct inode *inode, struct file *file)
 126 {
 127         struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
 128         int rv;
 129
 130         /* free the interrupt */
 131         free_irq(SGI_UART_VECTOR, sd);
 132
 133         /* ask SAL to close the subchannel */
 134         rv = ia64_sn_irtr_close(sd->sd_nasid, sd->sd_subch);
 135
 136         kfree(sd);
 137         return rv;
 138 }
 139
 140 /*
 141  * scdrv_read
 142  *
 143  * Called to read bytes from the open IRouter pipe.
 144  *
 145  */
 146
 147 static inline int
 148 read_status_check(struct subch_data_s *sd, int *len)
 149 {
 150         return ia64_sn_irtr_recv(sd->sd_nasid, sd->sd_subch, sd->sd_rb, len);
 151 }
 152
 153 static ssize_t
 154 scdrv_read(struct file *file, char __user *buf, size_t count, loff_t *f_pos)
 155 {
 156         int status;
 157         int len;
 158         unsigned long flags;
 159         struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
 160
 161         /* try to get control of the read buffer */
 162         if (down_trylock(&sd->sd_rbs)) {
 163                 /* somebody else has it now;
 164                  * if we're non-blocking, then exit...
 165                  */
 166                 if (file->f_flags & O_NONBLOCK) {
 167                         return -EAGAIN;
 168                 }
 169                 /* ...or if we want to block, then do so here */
 170                 if (down_interruptible(&sd->sd_rbs)) {
 171                         /* something went wrong with wait */
 172                         return -ERESTARTSYS;
 173                 }
 174         }
 175
 176         /* anything to read? */
 177         len = CHUNKSIZE;
 178         spin_lock_irqsave(&sd->sd_rlock, flags);
 179         status = read_status_check(sd, &len);
 180
 181         /* if not, and we're blocking I/O, loop */
 182         while (status < 0) {
 183                 DECLARE_WAITQUEUE(wait, current);
 184
 185                 if (file->f_flags & O_NONBLOCK) {
 186                         spin_unlock_irqrestore(&sd->sd_rlock, flags);
 187                         up(&sd->sd_rbs);
 188                         return -EAGAIN;
 189                 }
 190
 191                 len = CHUNKSIZE;
 192                 add_wait_queue(&sd->sd_rq, &wait);
 193                 set_current_state(TASK_INTERRUPTIBLE);
 194                 spin_unlock_irqrestore(&sd->sd_rlock, flags);
 195
 196                 schedule_timeout(SCDRV_TIMEOUT);
 197
 198                 remove_wait_queue(&sd->sd_rq, &wait);
 199                 if (signal_pending(current)) {
 200                         /* wait was interrupted */
 201                         up(&sd->sd_rbs);
 202                         return -ERESTARTSYS;
 203                 }
 204
 205                 spin_lock_irqsave(&sd->sd_rlock, flags);
 206                 status = read_status_check(sd, &len);
 207         }
 208         spin_unlock_irqrestore(&sd->sd_rlock, flags);
 209
 210         if (len > 0) {
 211                 /* we read something in the last read_status_check(); copy
 212                  * it out to user space
 213                  */
 214                 if (count < len) {
 215                         pr_debug("%s: only accepting %d of %d bytes\n",
 216                                  __FUNCTION__, (int) count, len);
 217                 }
 218                 len = min((int) count, len);
 219                 if (copy_to_user(buf, sd->sd_rb, len))
 220                         len = -EFAULT;
 221         }
 222
 223         /* release the read buffer and wake anyone who might be
 224          * waiting for it
 225          */
 226         up(&sd->sd_rbs);
 227
 228         /* return the number of characters read in */
 229         return len;
 230 }
 231
 232 /*
 233  * scdrv_write
 234  *
 235  * Writes a chunk of an IRouter packet (or other system controller data)
 236  * to the system controller.
 237  *
 238  */
 239 static inline int
 240 write_status_check(struct subch_data_s *sd, int count)
 241 {
 242         return ia64_sn_irtr_send(sd->sd_nasid, sd->sd_subch, sd->sd_wb, count);
 243 }
 244
 245 static ssize_t
 246 scdrv_write(struct file *file, const char __user *buf,
 247             size_t count, loff_t *f_pos)
 248 {
 249         unsigned long flags;
 250         int status;
 251         struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
 252
 253         /* try to get control of the write buffer */
 254         if (down_trylock(&sd->sd_wbs)) {
 255                 /* somebody else has it now;
 256                  * if we're non-blocking, then exit...
 257                  */
 258                 if (file->f_flags & O_NONBLOCK) {
 259                         return -EAGAIN;
 260                 }
 261                 /* ...or if we want to block, then do so here */
 262                 if (down_interruptible(&sd->sd_wbs)) {
 263                         /* something went wrong with wait */
 264                         return -ERESTARTSYS;
 265                 }
 266         }
 267
 268         count = min((int) count, CHUNKSIZE);
 269         if (copy_from_user(sd->sd_wb, buf, count)) {
 270                 up(&sd->sd_wbs);
 271                 return -EFAULT;
 272         }
 273
 274         /* try to send the buffer */
 275         spin_lock_irqsave(&sd->sd_wlock, flags);
 276         status = write_status_check(sd, count);
 277
 278         /* if we failed, and we want to block, then loop */
 279         while (status <= 0) {
 280                 DECLARE_WAITQUEUE(wait, current);
 281
 282                 if (file->f_flags & O_NONBLOCK) {
 283                         spin_unlock(&sd->sd_wlock);
 284                         up(&sd->sd_wbs);
 285                         return -EAGAIN;
 286                 }
 287
 288                 add_wait_queue(&sd->sd_wq, &wait);
 289                 set_current_state(TASK_INTERRUPTIBLE);
 290                 spin_unlock_irqrestore(&sd->sd_wlock, flags);
 291
 292                 schedule_timeout(SCDRV_TIMEOUT);
 293
 294                 remove_wait_queue(&sd->sd_wq, &wait);
 295                 if (signal_pending(current)) {
 296                         /* wait was interrupted */
 297                         up(&sd->sd_wbs);
 298                         return -ERESTARTSYS;
 299                 }
 300
 301                 spin_lock_irqsave(&sd->sd_wlock, flags);
 302                 status = write_status_check(sd, count);
 303         }
 304         spin_unlock_irqrestore(&sd->sd_wlock, flags);
 305
 306         /* release the write buffer and wake anyone who's waiting for it */
 307         up(&sd->sd_wbs);
 308
 309         /* return the number of characters accepted (should be the complete
 310          * "chunk" as requested)
 311          */
 312         if ((status >= 0) && (status < count)) {
 313                 pr_debug("Didn't accept the full chunk; %d of %d\n",
 314                          status, (int) count);
 315         }
 316         return status;
 317 }
 318
 319 static unsigned int
 320 scdrv_poll(struct file *file, struct poll_table_struct *wait)
 321 {
 322         unsigned int mask = 0;
 323         int status = 0;
 324         struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
 325         unsigned long flags;
 326
 327         poll_wait(file, &sd->sd_rq, wait);
 328         poll_wait(file, &sd->sd_wq, wait);
 329
 330         spin_lock_irqsave(&sd->sd_rlock, flags);
 331         spin_lock(&sd->sd_wlock);
 332         status = ia64_sn_irtr_intr(sd->sd_nasid, sd->sd_subch);
 333         spin_unlock(&sd->sd_wlock);
 334         spin_unlock_irqrestore(&sd->sd_rlock, flags);
 335
 336         if (status > 0) {
 337                 if (status & SAL_IROUTER_INTR_RECV) {
 338                         mask |= POLLIN | POLLRDNORM;
 339                 }
 340                 if (status & SAL_IROUTER_INTR_XMIT) {
 341                         mask |= POLLOUT | POLLWRNORM;
 342                 }
 343         }
 344
 345         return mask;
 346 }
 347
 348 static struct file_operations scdrv_fops = {
 349         .owner =        THIS_MODULE,
 350         .read =         scdrv_read,
 351         .write =        scdrv_write,
 352         .poll =         scdrv_poll,
 353         .open =         scdrv_open,
 354         .release =      scdrv_release,
 355 };
 356
 357 /*
 358  * scdrv_init
 359  *
 360  * Called at boot time to initialize the system controller communication
 361  * facility.
 362  */
 363 int __init
 364 scdrv_init(void)
 365 {
 366         geoid_t geoid;
 367         cmoduleid_t cmod;
 368         int i;
 369         char devname[32];
 370         char *devnamep;
 371         module_t *m;
 372         struct sysctl_data_s *scd;
 373         void *salbuf;
 374         struct class_simple *snsc_class;
 375         dev_t first_dev, dev;
 376
 377         if (alloc_chrdev_region(&first_dev, 0, (MAX_SLABS*nummodules),
 378                                 SYSCTL_BASENAME) < 0) {
 379                 printk("%s: failed to register SN system controller device\n",
 380                        __FUNCTION__);
 381                 return -ENODEV;
 382         }
 383         snsc_class = class_simple_create(THIS_MODULE, SYSCTL_BASENAME);
 384
 385         for (cmod = 0; cmod < nummodules; cmod++) {
 386                 m = sn_modules[cmod];
 387                 for (i = 0; i <= MAX_SLABS; i++) {
 388
 389                         if (m->nodes[i] == -1) {
 390                                 /* node is not alive in module */
 391                                 continue;
 392                         }
 393
 394                         geoid = m->geoid[i];
 395                         devnamep = devname;
 396                         format_module_id(devnamep, geo_module(geoid),
 397                                          MODULE_FORMAT_BRIEF);
 398                         devnamep = devname + strlen(devname);
 399                         sprintf(devnamep, "#%d", geo_slab(geoid));
 400
 401                         /* allocate sysctl device data */
 402                         scd = kmalloc(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                         }
 410                         memset(scd, 0, sizeof (struct sysctl_data_s));
 411
 412                         /* initialize sysctl device data fields */
 413                         scd->scd_nasid = cnodeid_to_nasid(m->nodes[i]);
 414                         if (!(salbuf = kmalloc(SCDRV_BUFSZ, GFP_KERNEL))) {
 415                                 printk("%s: failed to allocate driver buffer"
 416                                        "(%s%s)\n", __FUNCTION__,
 417                                        SYSCTL_BASENAME, devname);
 418                                 kfree(scd);
 419                                 continue;
 420                         }
 421
 422                         if (ia64_sn_irtr_init(scd->scd_nasid, salbuf,
 423                                               SCDRV_BUFSZ) < 0) {
 424                                 printk
 425                                     ("%s: failed to initialize SAL for"
 426                                      " system controller communication"
 427                                      " (%s/%s): outdated PROM?\n",
 428                                      __FUNCTION__, SYSCTL_BASENAME, devname);
 429                                 kfree(scd);
 430                                 kfree(salbuf);
 431                                 continue;
 432                         }
 433
 434                         dev = first_dev + m->nodes[i];
 435                         cdev_init(&scd->scd_cdev, &scdrv_fops);
 436                         if (cdev_add(&scd->scd_cdev, dev, 1)) {
 437                                 printk("%s: failed to register system"
 438                                        " controller device (%s%s)\n",
 439                                        __FUNCTION__, SYSCTL_BASENAME, devname);
 440                                 kfree(scd);
 441                                 kfree(salbuf);
 442                                 continue;
 443                         }
 444
 445                         class_simple_device_add(snsc_class, dev, NULL,
 446                                                 "%s", devname);
 447
 448                         ia64_sn_irtr_intr_enable(scd->scd_nasid,
 449                                                  0 /*ignored */ ,
 450                                                  SAL_IROUTER_INTR_RECV);
 451                 }
 452         }
 453         return 0;
 454 }
 455
 456 module_init(scdrv_init);