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