linux/drivers/char/snsc.c
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   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
  37static DEFINE_MUTEX(scdrv_mutex);
  38static irqreturn_t
  39scdrv_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
  71static int
  72scdrv_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
 129static int
 130scdrv_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
 152static inline int
 153read_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
 158static ssize_t
 159scdrv_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(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 */
 244static inline int
 245write_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
 250static ssize_t
 251scdrv_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(&sd->sd_wlock);
 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(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
 324static unsigned int
 325scdrv_poll(struct file *file, struct poll_table_struct *wait)
 326{
 327        unsigned int 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 |= POLLIN | POLLRDNORM;
 344                }
 345                if (status & SAL_IROUTER_INTR_XMIT) {
 346                        mask |= POLLOUT | POLLWRNORM;
 347                }
 348        }
 349
 350        return mask;
 351}
 352
 353static 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
 363static struct class *snsc_class;
 364
 365/*
 366 * scdrv_init
 367 *
 368 * Called at boot time to initialize the system controller communication
 369 * facility.
 370 */
 371int __init
 372scdrv_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        if (alloc_chrdev_region(&first_dev, 0, num_cnodes,
 389                                SYSCTL_BASENAME) < 0) {
 390                printk("%s: failed to register SN system controller device\n",
 391                       __func__);
 392                return -ENODEV;
 393        }
 394        snsc_class = class_create(THIS_MODULE, SYSCTL_BASENAME);
 395
 396        for (cnode = 0; cnode < num_cnodes; cnode++) {
 397                        geoid = cnodeid_get_geoid(cnode);
 398                        devnamep = devname;
 399                        format_module_id(devnamep, geo_module(geoid),
 400                                         MODULE_FORMAT_BRIEF);
 401                        devnamep = devname + strlen(devname);
 402                        sprintf(devnamep, "^%d#%d", geo_slot(geoid),
 403                                geo_slab(geoid));
 404
 405                        /* allocate sysctl device data */
 406                        scd = kzalloc(sizeof (struct sysctl_data_s),
 407                                      GFP_KERNEL);
 408                        if (!scd) {
 409                                printk("%s: failed to allocate device info"
 410                                       "for %s/%s\n", __func__,
 411                                       SYSCTL_BASENAME, devname);
 412                                continue;
 413                        }
 414
 415                        /* initialize sysctl device data fields */
 416                        scd->scd_nasid = cnodeid_to_nasid(cnode);
 417                        if (!(salbuf = kmalloc(SCDRV_BUFSZ, GFP_KERNEL))) {
 418                                printk("%s: failed to allocate driver buffer"
 419                                       "(%s%s)\n", __func__,
 420                                       SYSCTL_BASENAME, devname);
 421                                kfree(scd);
 422                                continue;
 423                        }
 424
 425                        if (ia64_sn_irtr_init(scd->scd_nasid, salbuf,
 426                                              SCDRV_BUFSZ) < 0) {
 427                                printk
 428                                    ("%s: failed to initialize SAL for"
 429                                     " system controller communication"
 430                                     " (%s/%s): outdated PROM?\n",
 431                                     __func__, SYSCTL_BASENAME, devname);
 432                                kfree(scd);
 433                                kfree(salbuf);
 434                                continue;
 435                        }
 436
 437                        dev = first_dev + cnode;
 438                        cdev_init(&scd->scd_cdev, &scdrv_fops);
 439                        if (cdev_add(&scd->scd_cdev, dev, 1)) {
 440                                printk("%s: failed to register system"
 441                                       " controller device (%s%s)\n",
 442                                       __func__, SYSCTL_BASENAME, devname);
 443                                kfree(scd);
 444                                kfree(salbuf);
 445                                continue;
 446                        }
 447
 448                        device_create(snsc_class, NULL, dev, NULL,
 449                                      "%s", devname);
 450
 451                        ia64_sn_irtr_intr_enable(scd->scd_nasid,
 452                                                 0 /*ignored */ ,
 453                                                 SAL_IROUTER_INTR_RECV);
 454
 455                        /* on the console nasid, prepare to receive
 456                         * system controller environmental events
 457                         */
 458                        if(scd->scd_nasid == event_nasid) {
 459                                scdrv_event_init(scd);
 460                        }
 461        }
 462        return 0;
 463}
 464
 465module_init(scdrv_init);
 466