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