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/signal.h>
  20 #include <linux/device.h>
  21 #include <linux/poll.h>
  22 #include <linux/init.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, SYSCTL_BASENAME, sd);
 112         if (rv) {
 113                 ia64_sn_irtr_close(sd->sd_nasid, sd->sd_subch);
 114                 kfree(sd);
 115                 printk("%s: irq request failed (%d)\n", __func__, rv);
 116                 mutex_unlock(&scdrv_mutex);
 117                 return -EBUSY;
 118         }
 119         mutex_unlock(&scdrv_mutex);
 120         return 0;
 121 }
 122
 123 /*
 124  * scdrv_release
 125  *
 126  * Release a previously-reserved subchannel.
 127  */
 128
 129 static int
 130 scdrv_release(struct inode *inode, struct file *file)
 131 {
 132         struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
 133         int rv;
 134
 135         /* free the interrupt */
 136         free_irq(SGI_UART_VECTOR, sd);
 137
 138         /* ask SAL to close the subchannel */
 139         rv = ia64_sn_irtr_close(sd->sd_nasid, sd->sd_subch);
 140
 141         kfree(sd);
 142         return rv;
 143 }
 144
 145 /*
 146  * scdrv_read
 147  *
 148  * Called to read bytes from the open IRouter pipe.
 149  *
 150  */
 151
 152 static inline int
 153 read_status_check(struct subch_data_s *sd, int *len)
 154 {
 155         return ia64_sn_irtr_recv(sd->sd_nasid, sd->sd_subch, sd->sd_rb, len);
 156 }
 157
 158 static ssize_t
 159 scdrv_read(struct file *file, char __user *buf, size_t count, loff_t *f_pos)
 160 {
 161         int status;
 162         int len;
 163         unsigned long flags;
 164         struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
 165
 166         /* try to get control of the read buffer */
 167         if (down_trylock(&sd->sd_rbs)) {
 168                 /* somebody else has it now;
 169                  * if we're non-blocking, then exit...
 170                  */
 171                 if (file->f_flags & O_NONBLOCK) {
 172                         return -EAGAIN;
 173                 }
 174                 /* ...or if we want to block, then do so here */
 175                 if (down_interruptible(&sd->sd_rbs)) {
 176                         /* something went wrong with wait */
 177                         return -ERESTARTSYS;
 178                 }
 179         }
 180
 181         /* anything to read? */
 182         len = CHUNKSIZE;
 183         spin_lock_irqsave(&sd->sd_rlock, flags);
 184         status = read_status_check(sd, &len);
 185
 186         /* if not, and we're blocking I/O, loop */
 187         while (status < 0) {
 188                 DECLARE_WAITQUEUE(wait, current);
 189
 190                 if (file->f_flags & O_NONBLOCK) {
 191                         spin_unlock_irqrestore(&sd->sd_rlock, flags);
 192                         up(&sd->sd_rbs);
 193                         return -EAGAIN;
 194                 }
 195
 196                 len = CHUNKSIZE;
 197                 set_current_state(TASK_INTERRUPTIBLE);
 198                 add_wait_queue(&sd->sd_rq, &wait);
 199                 spin_unlock_irqrestore(&sd->sd_rlock, flags);
 200
 201                 schedule_timeout(msecs_to_jiffies(SCDRV_TIMEOUT));
 202
 203                 remove_wait_queue(&sd->sd_rq, &wait);
 204                 if (signal_pending(current)) {
 205                         /* wait was interrupted */
 206                         up(&sd->sd_rbs);
 207                         return -ERESTARTSYS;
 208                 }
 209
 210                 spin_lock_irqsave(&sd->sd_rlock, flags);
 211                 status = read_status_check(sd, &len);
 212         }
 213         spin_unlock_irqrestore(&sd->sd_rlock, flags);
 214
 215         if (len > 0) {
 216                 /* we read something in the last read_status_check(); copy
 217                  * it out to user space
 218                  */
 219                 if (count < len) {
 220                         pr_debug("%s: only accepting %d of %d bytes\n",
 221                                  __func__, (int) count, len);
 222                 }
 223                 len = min((int) count, len);
 224                 if (copy_to_user(buf, sd->sd_rb, len))
 225                         len = -EFAULT;
 226         }
 227
 228         /* release the read buffer and wake anyone who might be
 229          * waiting for it
 230          */
 231         up(&sd->sd_rbs);
 232
 233         /* return the number of characters read in */
 234         return len;
 235 }
 236
 237 /*
 238  * scdrv_write
 239  *
 240  * Writes a chunk of an IRouter packet (or other system controller data)
 241  * to the system controller.
 242  *
 243  */
 244 static inline int
 245 write_status_check(struct subch_data_s *sd, int count)
 246 {
 247         return ia64_sn_irtr_send(sd->sd_nasid, sd->sd_subch, sd->sd_wb, count);
 248 }
 249
 250 static ssize_t
 251 scdrv_write(struct file *file, const char __user *buf,
 252             size_t count, loff_t *f_pos)
 253 {
 254         unsigned long flags;
 255         int status;
 256         struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
 257
 258         /* try to get control of the write buffer */
 259         if (down_trylock(&sd->sd_wbs)) {
 260                 /* somebody else has it now;
 261                  * if we're non-blocking, then exit...
 262                  */
 263                 if (file->f_flags & O_NONBLOCK) {
 264                         return -EAGAIN;
 265                 }
 266                 /* ...or if we want to block, then do so here */
 267                 if (down_interruptible(&sd->sd_wbs)) {
 268                         /* something went wrong with wait */
 269                         return -ERESTARTSYS;
 270                 }
 271         }
 272
 273         count = min((int) count, CHUNKSIZE);
 274         if (copy_from_user(sd->sd_wb, buf, count)) {
 275                 up(&sd->sd_wbs);
 276                 return -EFAULT;
 277         }
 278
 279         /* try to send the buffer */
 280         spin_lock_irqsave(&sd->sd_wlock, flags);
 281         status = write_status_check(sd, count);
 282
 283         /* if we failed, and we want to block, then loop */
 284         while (status <= 0) {
 285                 DECLARE_WAITQUEUE(wait, current);
 286
 287                 if (file->f_flags & O_NONBLOCK) {
 288                         spin_unlock_irqrestore(&sd->sd_wlock, flags);
 289                         up(&sd->sd_wbs);
 290                         return -EAGAIN;
 291                 }
 292
 293                 set_current_state(TASK_INTERRUPTIBLE);
 294                 add_wait_queue(&sd->sd_wq, &wait);
 295                 spin_unlock_irqrestore(&sd->sd_wlock, flags);
 296
 297                 schedule_timeout(msecs_to_jiffies(SCDRV_TIMEOUT));
 298
 299                 remove_wait_queue(&sd->sd_wq, &wait);
 300                 if (signal_pending(current)) {
 301                         /* wait was interrupted */
 302                         up(&sd->sd_wbs);
 303                         return -ERESTARTSYS;
 304                 }
 305
 306                 spin_lock_irqsave(&sd->sd_wlock, flags);
 307                 status = write_status_check(sd, count);
 308         }
 309         spin_unlock_irqrestore(&sd->sd_wlock, flags);
 310
 311         /* release the write buffer and wake anyone who's waiting for it */
 312         up(&sd->sd_wbs);
 313
 314         /* return the number of characters accepted (should be the complete
 315          * "chunk" as requested)
 316          */
 317         if ((status >= 0) && (status < count)) {
 318                 pr_debug("Didn't accept the full chunk; %d of %d\n",
 319                          status, (int) count);
 320         }
 321         return status;
 322 }
 323
 324 static __poll_t
 325 scdrv_poll(struct file *file, struct poll_table_struct *wait)
 326 {
 327         __poll_t mask = 0;
 328         int status = 0;
 329         struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
 330         unsigned long flags;
 331
 332         poll_wait(file, &sd->sd_rq, wait);
 333         poll_wait(file, &sd->sd_wq, wait);
 334
 335         spin_lock_irqsave(&sd->sd_rlock, flags);
 336         spin_lock(&sd->sd_wlock);
 337         status = ia64_sn_irtr_intr(sd->sd_nasid, sd->sd_subch);
 338         spin_unlock(&sd->sd_wlock);
 339         spin_unlock_irqrestore(&sd->sd_rlock, flags);
 340
 341         if (status > 0) {
 342                 if (status & SAL_IROUTER_INTR_RECV) {
 343                         mask |= EPOLLIN | EPOLLRDNORM;
 344                 }
 345                 if (status & SAL_IROUTER_INTR_XMIT) {
 346                         mask |= EPOLLOUT | EPOLLWRNORM;
 347                 }
 348         }
 349
 350         return mask;
 351 }
 352
 353 static const struct file_operations scdrv_fops = {
 354         .owner =        THIS_MODULE,
 355         .read =         scdrv_read,
 356         .write =        scdrv_write,
 357         .poll =         scdrv_poll,
 358         .open =         scdrv_open,
 359         .release =      scdrv_release,
 360         .llseek =       noop_llseek,
 361 };
 362
 363 static struct class *snsc_class;
 364
 365 /*
 366  * scdrv_init
 367  *
 368  * Called at boot time to initialize the system controller communication
 369  * facility.
 370  */
 371 int __init
 372 scdrv_init(void)
 373 {
 374         geoid_t geoid;
 375         cnodeid_t cnode;
 376         char devname[32];
 377         char *devnamep;
 378         struct sysctl_data_s *scd;
 379         void *salbuf;
 380         dev_t first_dev, dev;
 381         nasid_t event_nasid;
 382
 383         if (!ia64_platform_is("sn2"))
 384                 return -ENODEV;
 385
 386         event_nasid = ia64_sn_get_console_nasid();
 387
 388         snsc_class = class_create(THIS_MODULE, SYSCTL_BASENAME);
 389         if (IS_ERR(snsc_class)) {
 390                 printk("%s: failed to allocate class\n", __func__);
 391                 return PTR_ERR(snsc_class);
 392         }
 393
 394         if (alloc_chrdev_region(&first_dev, 0, num_cnodes,
 395                                 SYSCTL_BASENAME) < 0) {
 396                 printk("%s: failed to register SN system controller device\n",
 397                        __func__);
 398                 return -ENODEV;
 399         }
 400
 401         for (cnode = 0; cnode < num_cnodes; cnode++) {
 402                         geoid = cnodeid_get_geoid(cnode);
 403                         devnamep = devname;
 404                         format_module_id(devnamep, geo_module(geoid),
 405                                          MODULE_FORMAT_BRIEF);
 406                         devnamep = devname + strlen(devname);
 407                         sprintf(devnamep, "^%d#%d", geo_slot(geoid),
 408                                 geo_slab(geoid));
 409
 410                         /* allocate sysctl device data */
 411                         scd = kzalloc(sizeof (struct sysctl_data_s),
 412                                       GFP_KERNEL);
 413                         if (!scd) {
 414                                 printk("%s: failed to allocate device info"
 415                                        "for %s/%s\n", __func__,
 416                                        SYSCTL_BASENAME, devname);
 417                                 continue;
 418                         }
 419
 420                         /* initialize sysctl device data fields */
 421                         scd->scd_nasid = cnodeid_to_nasid(cnode);
 422                         if (!(salbuf = kmalloc(SCDRV_BUFSZ, GFP_KERNEL))) {
 423                                 printk("%s: failed to allocate driver buffer"
 424                                        "(%s%s)\n", __func__,
 425                                        SYSCTL_BASENAME, devname);
 426                                 kfree(scd);
 427                                 continue;
 428                         }
 429
 430                         if (ia64_sn_irtr_init(scd->scd_nasid, salbuf,
 431                                               SCDRV_BUFSZ) < 0) {
 432                                 printk
 433                                     ("%s: failed to initialize SAL for"
 434                                      " system controller communication"
 435                                      " (%s/%s): outdated PROM?\n",
 436                                      __func__, SYSCTL_BASENAME, devname);
 437                                 kfree(scd);
 438                                 kfree(salbuf);
 439                                 continue;
 440                         }
 441
 442                         dev = first_dev + cnode;
 443                         cdev_init(&scd->scd_cdev, &scdrv_fops);
 444                         if (cdev_add(&scd->scd_cdev, dev, 1)) {
 445                                 printk("%s: failed to register system"
 446                                        " controller device (%s%s)\n",
 447                                        __func__, SYSCTL_BASENAME, devname);
 448                                 kfree(scd);
 449                                 kfree(salbuf);
 450                                 continue;
 451                         }
 452
 453                         device_create(snsc_class, NULL, dev, NULL,
 454                                       "%s", devname);
 455
 456                         ia64_sn_irtr_intr_enable(scd->scd_nasid,
 457                                                  0 /*ignored */ ,
 458                                                  SAL_IROUTER_INTR_RECV);
 459
 460                         /* on the console nasid, prepare to receive
 461                          * system controller environmental events
 462                          */
 463                         if(scd->scd_nasid == event_nasid) {
 464                                 scdrv_event_init(scd);
 465                         }
 466         }
 467         return 0;
 468 }
 469 device_initcall(scdrv_init);