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