drivers/misc/ioc4.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 2005-2006 Silicon Graphics, Inc.  All Rights Reserved.
   7  */
   8
   9 /* This file contains the master driver module for use by SGI IOC4 subdrivers.
  10  *
  11  * It allocates any resources shared between multiple subdevices, and
  12  * provides accessor functions (where needed) and the like for those
  13  * resources.  It also provides a mechanism for the subdevice modules
  14  * to support loading and unloading.
  15  *
  16  * Non-shared resources (e.g. external interrupt A_INT_OUT register page
  17  * alias, serial port and UART registers) are handled by the subdevice
  18  * modules themselves.
  19  *
  20  * This is all necessary because IOC4 is not implemented as a multi-function
  21  * PCI device, but an amalgamation of disparate registers for several
  22  * types of device (ATA, serial, external interrupts).  The normal
  23  * resource management in the kernel doesn't have quite the right interfaces
  24  * to handle this situation (e.g. multiple modules can't claim the same
  25  * PCI ID), thus this IOC4 master module.
  26  */
  27
  28 #include <linux/errno.h>
  29 #include <linux/module.h>
  30 #include <linux/pci.h>
  31 #include <linux/ioc4.h>
  32 #include <linux/ktime.h>
  33 #include <linux/mutex.h>
  34 #include <linux/time.h>
  35 #include <asm/io.h>
  36
  37 /***************
  38  * Definitions *
  39  ***************/
  40
  41 /* Tweakable values */
  42
  43 /* PCI bus speed detection/calibration */
  44 #define IOC4_CALIBRATE_COUNT 63         /* Calibration cycle period */
  45 #define IOC4_CALIBRATE_CYCLES 256       /* Average over this many cycles */
  46 #define IOC4_CALIBRATE_DISCARD 2        /* Discard first few cycles */
  47 #define IOC4_CALIBRATE_LOW_MHZ 25       /* Lower bound on bus speed sanity */
  48 #define IOC4_CALIBRATE_HIGH_MHZ 75      /* Upper bound on bus speed sanity */
  49 #define IOC4_CALIBRATE_DEFAULT_MHZ 66   /* Assumed if sanity check fails */
  50
  51 /************************
  52  * Submodule management *
  53  ************************/
  54
  55 static DEFINE_MUTEX(ioc4_mutex);
  56
  57 static LIST_HEAD(ioc4_devices);
  58 static LIST_HEAD(ioc4_submodules);
  59
  60 /* Register an IOC4 submodule */
  61 int
  62 ioc4_register_submodule(struct ioc4_submodule *is)
  63 {
  64         struct ioc4_driver_data *idd;
  65
  66         mutex_lock(&ioc4_mutex);
  67         list_add(&is->is_list, &ioc4_submodules);
  68
  69         /* Initialize submodule for each IOC4 */
  70         if (!is->is_probe)
  71                 goto out;
  72
  73         list_for_each_entry(idd, &ioc4_devices, idd_list) {
  74                 if (is->is_probe(idd)) {
  75                         printk(KERN_WARNING
  76                                "%s: IOC4 submodule %s probe failed "
  77                                "for pci_dev %s",
  78                                __func__, module_name(is->is_owner),
  79                                pci_name(idd->idd_pdev));
  80                 }
  81         }
  82  out:
  83         mutex_unlock(&ioc4_mutex);
  84         return 0;
  85 }
  86
  87 /* Unregister an IOC4 submodule */
  88 void
  89 ioc4_unregister_submodule(struct ioc4_submodule *is)
  90 {
  91         struct ioc4_driver_data *idd;
  92
  93         mutex_lock(&ioc4_mutex);
  94         list_del(&is->is_list);
  95
  96         /* Remove submodule for each IOC4 */
  97         if (!is->is_remove)
  98                 goto out;
  99
 100         list_for_each_entry(idd, &ioc4_devices, idd_list) {
 101                 if (is->is_remove(idd)) {
 102                         printk(KERN_WARNING
 103                                "%s: IOC4 submodule %s remove failed "
 104                                "for pci_dev %s.\n",
 105                                __func__, module_name(is->is_owner),
 106                                pci_name(idd->idd_pdev));
 107                 }
 108         }
 109  out:
 110         mutex_unlock(&ioc4_mutex);
 111 }
 112
 113 /*********************
 114  * Device management *
 115  *********************/
 116
 117 #define IOC4_CALIBRATE_LOW_LIMIT \
 118         (1000*IOC4_EXTINT_COUNT_DIVISOR/IOC4_CALIBRATE_LOW_MHZ)
 119 #define IOC4_CALIBRATE_HIGH_LIMIT \
 120         (1000*IOC4_EXTINT_COUNT_DIVISOR/IOC4_CALIBRATE_HIGH_MHZ)
 121 #define IOC4_CALIBRATE_DEFAULT \
 122         (1000*IOC4_EXTINT_COUNT_DIVISOR/IOC4_CALIBRATE_DEFAULT_MHZ)
 123
 124 #define IOC4_CALIBRATE_END \
 125         (IOC4_CALIBRATE_CYCLES + IOC4_CALIBRATE_DISCARD)
 126
 127 #define IOC4_INT_OUT_MODE_TOGGLE 0x7    /* Toggle INT_OUT every COUNT+1 ticks */
 128
 129 /* Determines external interrupt output clock period of the PCI bus an
 130  * IOC4 is attached to.  This value can be used to determine the PCI
 131  * bus speed.
 132  *
 133  * IOC4 has a design feature that various internal timers are derived from
 134  * the PCI bus clock.  This causes IOC4 device drivers to need to take the
 135  * bus speed into account when setting various register values (e.g. INT_OUT
 136  * register COUNT field, UART divisors, etc).  Since this information is
 137  * needed by several subdrivers, it is determined by the main IOC4 driver,
 138  * even though the following code utilizes external interrupt registers
 139  * to perform the speed calculation.
 140  */
 141 static void
 142 ioc4_clock_calibrate(struct ioc4_driver_data *idd)
 143 {
 144         union ioc4_int_out int_out;
 145         union ioc4_gpcr gpcr;
 146         unsigned int state, last_state = 1;
 147         struct timespec start_ts, end_ts;
 148         uint64_t start, end, period;
 149         unsigned int count = 0;
 150
 151         /* Enable output */
 152         gpcr.raw = 0;
 153         gpcr.fields.dir = IOC4_GPCR_DIR_0;
 154         gpcr.fields.int_out_en = 1;
 155         writel(gpcr.raw, &idd->idd_misc_regs->gpcr_s.raw);
 156
 157         /* Reset to power-on state */
 158         writel(0, &idd->idd_misc_regs->int_out.raw);
 159         mmiowb();
 160
 161         /* Set up square wave */
 162         int_out.raw = 0;
 163         int_out.fields.count = IOC4_CALIBRATE_COUNT;
 164         int_out.fields.mode = IOC4_INT_OUT_MODE_TOGGLE;
 165         int_out.fields.diag = 0;
 166         writel(int_out.raw, &idd->idd_misc_regs->int_out.raw);
 167         mmiowb();
 168
 169         /* Check square wave period averaged over some number of cycles */
 170         do {
 171                 int_out.raw = readl(&idd->idd_misc_regs->int_out.raw);
 172                 state = int_out.fields.int_out;
 173                 if (!last_state && state) {
 174                         count++;
 175                         if (count == IOC4_CALIBRATE_END) {
 176                                 ktime_get_ts(&end_ts);
 177                                 break;
 178                         } else if (count == IOC4_CALIBRATE_DISCARD)
 179                                 ktime_get_ts(&start_ts);
 180                 }
 181                 last_state = state;
 182         } while (1);
 183
 184         /* Calculation rearranged to preserve intermediate precision.
 185          * Logically:
 186          * 1. "end - start" gives us the measurement period over all
 187          *    the square wave cycles.
 188          * 2. Divide by number of square wave cycles to get the period
 189          *    of a square wave cycle.
 190          * 3. Divide by 2*(int_out.fields.count+1), which is the formula
 191          *    by which the IOC4 generates the square wave, to get the
 192          *    period of an IOC4 INT_OUT count.
 193          */
 194         end = end_ts.tv_sec * NSEC_PER_SEC + end_ts.tv_nsec;
 195         start = start_ts.tv_sec * NSEC_PER_SEC + start_ts.tv_nsec;
 196         period = (end - start) /
 197                 (IOC4_CALIBRATE_CYCLES * 2 * (IOC4_CALIBRATE_COUNT + 1));
 198
 199         /* Bounds check the result. */
 200         if (period > IOC4_CALIBRATE_LOW_LIMIT ||
 201             period < IOC4_CALIBRATE_HIGH_LIMIT) {
 202                 printk(KERN_INFO
 203                        "IOC4 %s: Clock calibration failed.  Assuming"
 204                        "PCI clock is %d ns.\n",
 205                        pci_name(idd->idd_pdev),
 206                        IOC4_CALIBRATE_DEFAULT / IOC4_EXTINT_COUNT_DIVISOR);
 207                 period = IOC4_CALIBRATE_DEFAULT;
 208         } else {
 209                 u64 ns = period;
 210
 211                 do_div(ns, IOC4_EXTINT_COUNT_DIVISOR);
 212                 printk(KERN_DEBUG
 213                        "IOC4 %s: PCI clock is %llu ns.\n",
 214                        pci_name(idd->idd_pdev), (unsigned long long)ns);
 215         }
 216
 217         /* Remember results.  We store the extint clock period rather
 218          * than the PCI clock period so that greater precision is
 219          * retained.  Divide by IOC4_EXTINT_COUNT_DIVISOR to get
 220          * PCI clock period.
 221          */
 222         idd->count_period = period;
 223 }
 224
 225 /* There are three variants of IOC4 cards: IO9, IO10, and PCI-RT.
 226  * Each brings out different combinations of IOC4 signals, thus.
 227  * the IOC4 subdrivers need to know to which we're attached.
 228  *
 229  * We look for the presence of a SCSI (IO9) or SATA (IO10) controller
 230  * on the same PCI bus at slot number 3 to differentiate IO9 from IO10.
 231  * If neither is present, it's a PCI-RT.
 232  */
 233 static unsigned int
 234 ioc4_variant(struct ioc4_driver_data *idd)
 235 {
 236         struct pci_dev *pdev = NULL;
 237         int found = 0;
 238
 239         /* IO9: Look for a QLogic ISP 12160 at the same bus and slot 3. */
 240         do {
 241                 pdev = pci_get_device(PCI_VENDOR_ID_QLOGIC,
 242                                       PCI_DEVICE_ID_QLOGIC_ISP12160, pdev);
 243                 if (pdev &&
 244                     idd->idd_pdev->bus->number == pdev->bus->number &&
 245                     3 == PCI_SLOT(pdev->devfn))
 246                         found = 1;
 247         } while (pdev && !found);
 248         if (NULL != pdev) {
 249                 pci_dev_put(pdev);
 250                 return IOC4_VARIANT_IO9;
 251         }
 252
 253         /* IO10: Look for a Vitesse VSC 7174 at the same bus and slot 3. */
 254         pdev = NULL;
 255         do {
 256                 pdev = pci_get_device(PCI_VENDOR_ID_VITESSE,
 257                                       PCI_DEVICE_ID_VITESSE_VSC7174, pdev);
 258                 if (pdev &&
 259                     idd->idd_pdev->bus->number == pdev->bus->number &&
 260                     3 == PCI_SLOT(pdev->devfn))
 261                         found = 1;
 262         } while (pdev && !found);
 263         if (NULL != pdev) {
 264                 pci_dev_put(pdev);
 265                 return IOC4_VARIANT_IO10;
 266         }
 267
 268         /* PCI-RT: No SCSI/SATA controller will be present */
 269         return IOC4_VARIANT_PCI_RT;
 270 }
 271
 272 static void
 273 ioc4_load_modules(struct work_struct *work)
 274 {
 275         /* arg just has to be freed */
 276
 277         request_module("sgiioc4");
 278
 279         kfree(work);
 280 }
 281
 282 /* Adds a new instance of an IOC4 card */
 283 static int
 284 ioc4_probe(struct pci_dev *pdev, const struct pci_device_id *pci_id)
 285 {
 286         struct ioc4_driver_data *idd;
 287         struct ioc4_submodule *is;
 288         uint32_t pcmd;
 289         int ret;
 290
 291         /* Enable IOC4 and take ownership of it */
 292         if ((ret = pci_enable_device(pdev))) {
 293                 printk(KERN_WARNING
 294                        "%s: Failed to enable IOC4 device for pci_dev %s.\n",
 295                        __func__, pci_name(pdev));
 296                 goto out;
 297         }
 298         pci_set_master(pdev);
 299
 300         /* Set up per-IOC4 data */
 301         idd = kmalloc(sizeof(struct ioc4_driver_data), GFP_KERNEL);
 302         if (!idd) {
 303                 printk(KERN_WARNING
 304                        "%s: Failed to allocate IOC4 data for pci_dev %s.\n",
 305                        __func__, pci_name(pdev));
 306                 ret = -ENODEV;
 307                 goto out_idd;
 308         }
 309         idd->idd_pdev = pdev;
 310         idd->idd_pci_id = pci_id;
 311
 312         /* Map IOC4 misc registers.  These are shared between subdevices
 313          * so the main IOC4 module manages them.
 314          */
 315         idd->idd_bar0 = pci_resource_start(idd->idd_pdev, 0);
 316         if (!idd->idd_bar0) {
 317                 printk(KERN_WARNING
 318                        "%s: Unable to find IOC4 misc resource "
 319                        "for pci_dev %s.\n",
 320                        __func__, pci_name(idd->idd_pdev));
 321                 ret = -ENODEV;
 322                 goto out_pci;
 323         }
 324         if (!request_mem_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs),
 325                             "ioc4_misc")) {
 326                 printk(KERN_WARNING
 327                        "%s: Unable to request IOC4 misc region "
 328                        "for pci_dev %s.\n",
 329                        __func__, pci_name(idd->idd_pdev));
 330                 ret = -ENODEV;
 331                 goto out_pci;
 332         }
 333         idd->idd_misc_regs = ioremap(idd->idd_bar0,
 334                                      sizeof(struct ioc4_misc_regs));
 335         if (!idd->idd_misc_regs) {
 336                 printk(KERN_WARNING
 337                        "%s: Unable to remap IOC4 misc region "
 338                        "for pci_dev %s.\n",
 339                        __func__, pci_name(idd->idd_pdev));
 340                 ret = -ENODEV;
 341                 goto out_misc_region;
 342         }
 343
 344         /* Failsafe portion of per-IOC4 initialization */
 345
 346         /* Detect card variant */
 347         idd->idd_variant = ioc4_variant(idd);
 348         printk(KERN_INFO "IOC4 %s: %s card detected.\n", pci_name(pdev),
 349                idd->idd_variant == IOC4_VARIANT_IO9 ? "IO9" :
 350                idd->idd_variant == IOC4_VARIANT_PCI_RT ? "PCI-RT" :
 351                idd->idd_variant == IOC4_VARIANT_IO10 ? "IO10" : "unknown");
 352
 353         /* Initialize IOC4 */
 354         pci_read_config_dword(idd->idd_pdev, PCI_COMMAND, &pcmd);
 355         pci_write_config_dword(idd->idd_pdev, PCI_COMMAND,
 356                                pcmd | PCI_COMMAND_PARITY | PCI_COMMAND_SERR);
 357
 358         /* Determine PCI clock */
 359         ioc4_clock_calibrate(idd);
 360
 361         /* Disable/clear all interrupts.  Need to do this here lest
 362          * one submodule request the shared IOC4 IRQ, but interrupt
 363          * is generated by a different subdevice.
 364          */
 365         /* Disable */
 366         writel(~0, &idd->idd_misc_regs->other_iec.raw);
 367         writel(~0, &idd->idd_misc_regs->sio_iec);
 368         /* Clear (i.e. acknowledge) */
 369         writel(~0, &idd->idd_misc_regs->other_ir.raw);
 370         writel(~0, &idd->idd_misc_regs->sio_ir);
 371
 372         /* Track PCI-device specific data */
 373         idd->idd_serial_data = NULL;
 374         pci_set_drvdata(idd->idd_pdev, idd);
 375
 376         mutex_lock(&ioc4_mutex);
 377         list_add_tail(&idd->idd_list, &ioc4_devices);
 378
 379         /* Add this IOC4 to all submodules */
 380         list_for_each_entry(is, &ioc4_submodules, is_list) {
 381                 if (is->is_probe && is->is_probe(idd)) {
 382                         printk(KERN_WARNING
 383                                "%s: IOC4 submodule 0x%s probe failed "
 384                                "for pci_dev %s.\n",
 385                                __func__, module_name(is->is_owner),
 386                                pci_name(idd->idd_pdev));
 387                 }
 388         }
 389         mutex_unlock(&ioc4_mutex);
 390
 391         /* Request sgiioc4 IDE driver on boards that bring that functionality
 392          * off of IOC4.  The root filesystem may be hosted on a drive connected
 393          * to IOC4, so we need to make sure the sgiioc4 driver is loaded as it
 394          * won't be picked up by modprobes due to the ioc4 module owning the
 395          * PCI device.
 396          */
 397         if (idd->idd_variant != IOC4_VARIANT_PCI_RT) {
 398                 struct work_struct *work;
 399                 work = kzalloc(sizeof(struct work_struct), GFP_KERNEL);
 400                 if (!work) {
 401                         printk(KERN_WARNING
 402                                "%s: IOC4 unable to allocate memory for "
 403                                "load of sub-modules.\n", __func__);
 404                 } else {
 405                         /* Request the module from a work procedure as the
 406                          * modprobe goes out to a userland helper and that
 407                          * will hang if done directly from ioc4_probe().
 408                          */
 409                         printk(KERN_INFO "IOC4 loading sgiioc4 submodule\n");
 410                         INIT_WORK(work, ioc4_load_modules);
 411                         schedule_work(work);
 412                 }
 413         }
 414
 415         return 0;
 416
 417 out_misc_region:
 418         release_mem_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs));
 419 out_pci:
 420         kfree(idd);
 421 out_idd:
 422         pci_disable_device(pdev);
 423 out:
 424         return ret;
 425 }
 426
 427 /* Removes a particular instance of an IOC4 card. */
 428 static void
 429 ioc4_remove(struct pci_dev *pdev)
 430 {
 431         struct ioc4_submodule *is;
 432         struct ioc4_driver_data *idd;
 433
 434         idd = pci_get_drvdata(pdev);
 435
 436         /* Remove this IOC4 from all submodules */
 437         mutex_lock(&ioc4_mutex);
 438         list_for_each_entry(is, &ioc4_submodules, is_list) {
 439                 if (is->is_remove && is->is_remove(idd)) {
 440                         printk(KERN_WARNING
 441                                "%s: IOC4 submodule 0x%s remove failed "
 442                                "for pci_dev %s.\n",
 443                                __func__, module_name(is->is_owner),
 444                                pci_name(idd->idd_pdev));
 445                 }
 446         }
 447         mutex_unlock(&ioc4_mutex);
 448
 449         /* Release resources */
 450         iounmap(idd->idd_misc_regs);
 451         if (!idd->idd_bar0) {
 452                 printk(KERN_WARNING
 453                        "%s: Unable to get IOC4 misc mapping for pci_dev %s. "
 454                        "Device removal may be incomplete.\n",
 455                        __func__, pci_name(idd->idd_pdev));
 456         }
 457         release_mem_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs));
 458
 459         /* Disable IOC4 and relinquish */
 460         pci_disable_device(pdev);
 461
 462         /* Remove and free driver data */
 463         mutex_lock(&ioc4_mutex);
 464         list_del(&idd->idd_list);
 465         mutex_unlock(&ioc4_mutex);
 466         kfree(idd);
 467 }
 468
 469 static struct pci_device_id ioc4_id_table[] = {
 470         {PCI_VENDOR_ID_SGI, PCI_DEVICE_ID_SGI_IOC4, PCI_ANY_ID,
 471          PCI_ANY_ID, 0x0b4000, 0xFFFFFF},
 472         {0}
 473 };
 474
 475 static struct pci_driver ioc4_driver = {
 476         .name = "IOC4",
 477         .id_table = ioc4_id_table,
 478         .probe = ioc4_probe,
 479         .remove = ioc4_remove,
 480 };
 481
 482 MODULE_DEVICE_TABLE(pci, ioc4_id_table);
 483
 484 /*********************
 485  * Module management *
 486  *********************/
 487
 488 /* Module load */
 489 static int __devinit
 490 ioc4_init(void)
 491 {
 492         return pci_register_driver(&ioc4_driver);
 493 }
 494
 495 /* Module unload */
 496 static void __devexit
 497 ioc4_exit(void)
 498 {
 499         /* Ensure ioc4_load_modules() has completed before exiting */
 500         flush_scheduled_work();
 501         pci_unregister_driver(&ioc4_driver);
 502 }
 503
 504 module_init(ioc4_init);
 505 module_exit(ioc4_exit);
 506
 507 MODULE_AUTHOR("Brent Casavant - Silicon Graphics, Inc. <bcasavan@sgi.com>");
 508 MODULE_DESCRIPTION("PCI driver master module for SGI IOC4 Base-IO Card");
 509 MODULE_LICENSE("GPL");
 510
 511 EXPORT_SYMBOL(ioc4_register_submodule);
 512 EXPORT_SYMBOL(ioc4_unregister_submodule);