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/slab.h>
  34 #include <linux/mutex.h>
  35 #include <linux/time.h>
  36 #include <asm/io.h>
  37
  38 /***************
  39  * Definitions *
  40  ***************/
  41
  42 /* Tweakable values */
  43
  44 /* PCI bus speed detection/calibration */
  45 #define IOC4_CALIBRATE_COUNT 63         /* Calibration cycle period */
  46 #define IOC4_CALIBRATE_CYCLES 256       /* Average over this many cycles */
  47 #define IOC4_CALIBRATE_DISCARD 2        /* Discard first few cycles */
  48 #define IOC4_CALIBRATE_LOW_MHZ 25       /* Lower bound on bus speed sanity */
  49 #define IOC4_CALIBRATE_HIGH_MHZ 75      /* Upper bound on bus speed sanity */
  50 #define IOC4_CALIBRATE_DEFAULT_MHZ 66   /* Assumed if sanity check fails */
  51
  52 /************************
  53  * Submodule management *
  54  ************************/
  55
  56 static DEFINE_MUTEX(ioc4_mutex);
  57
  58 static LIST_HEAD(ioc4_devices);
  59 static LIST_HEAD(ioc4_submodules);
  60
  61 /* Register an IOC4 submodule */
  62 int
  63 ioc4_register_submodule(struct ioc4_submodule *is)
  64 {
  65         struct ioc4_driver_data *idd;
  66
  67         mutex_lock(&ioc4_mutex);
  68         list_add(&is->is_list, &ioc4_submodules);
  69
  70         /* Initialize submodule for each IOC4 */
  71         if (!is->is_probe)
  72                 goto out;
  73
  74         list_for_each_entry(idd, &ioc4_devices, idd_list) {
  75                 if (is->is_probe(idd)) {
  76                         printk(KERN_WARNING
  77                                "%s: IOC4 submodule %s probe failed "
  78                                "for pci_dev %s",
  79                                __func__, module_name(is->is_owner),
  80                                pci_name(idd->idd_pdev));
  81                 }
  82         }
  83  out:
  84         mutex_unlock(&ioc4_mutex);
  85         return 0;
  86 }
  87
  88 /* Unregister an IOC4 submodule */
  89 void
  90 ioc4_unregister_submodule(struct ioc4_submodule *is)
  91 {
  92         struct ioc4_driver_data *idd;
  93
  94         mutex_lock(&ioc4_mutex);
  95         list_del(&is->is_list);
  96
  97         /* Remove submodule for each IOC4 */
  98         if (!is->is_remove)
  99                 goto out;
 100
 101         list_for_each_entry(idd, &ioc4_devices, idd_list) {
 102                 if (is->is_remove(idd)) {
 103                         printk(KERN_WARNING
 104                                "%s: IOC4 submodule %s remove failed "
 105                                "for pci_dev %s.\n",
 106                                __func__, module_name(is->is_owner),
 107                                pci_name(idd->idd_pdev));
 108                 }
 109         }
 110  out:
 111         mutex_unlock(&ioc4_mutex);
 112 }
 113
 114 /*********************
 115  * Device management *
 116  *********************/
 117
 118 #define IOC4_CALIBRATE_LOW_LIMIT \
 119         (1000*IOC4_EXTINT_COUNT_DIVISOR/IOC4_CALIBRATE_LOW_MHZ)
 120 #define IOC4_CALIBRATE_HIGH_LIMIT \
 121         (1000*IOC4_EXTINT_COUNT_DIVISOR/IOC4_CALIBRATE_HIGH_MHZ)
 122 #define IOC4_CALIBRATE_DEFAULT \
 123         (1000*IOC4_EXTINT_COUNT_DIVISOR/IOC4_CALIBRATE_DEFAULT_MHZ)
 124
 125 #define IOC4_CALIBRATE_END \
 126         (IOC4_CALIBRATE_CYCLES + IOC4_CALIBRATE_DISCARD)
 127
 128 #define IOC4_INT_OUT_MODE_TOGGLE 0x7    /* Toggle INT_OUT every COUNT+1 ticks */
 129
 130 /* Determines external interrupt output clock period of the PCI bus an
 131  * IOC4 is attached to.  This value can be used to determine the PCI
 132  * bus speed.
 133  *
 134  * IOC4 has a design feature that various internal timers are derived from
 135  * the PCI bus clock.  This causes IOC4 device drivers to need to take the
 136  * bus speed into account when setting various register values (e.g. INT_OUT
 137  * register COUNT field, UART divisors, etc).  Since this information is
 138  * needed by several subdrivers, it is determined by the main IOC4 driver,
 139  * even though the following code utilizes external interrupt registers
 140  * to perform the speed calculation.
 141  */
 142 static void
 143 ioc4_clock_calibrate(struct ioc4_driver_data *idd)
 144 {
 145         union ioc4_int_out int_out;
 146         union ioc4_gpcr gpcr;
 147         unsigned int state, last_state = 1;
 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                                 end = ktime_get_ns();
 177                                 break;
 178                         } else if (count == IOC4_CALIBRATE_DISCARD)
 179                                 start = ktime_get_ns();
 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         period = (end - start) /
 195                 (IOC4_CALIBRATE_CYCLES * 2 * (IOC4_CALIBRATE_COUNT + 1));
 196
 197         /* Bounds check the result. */
 198         if (period > IOC4_CALIBRATE_LOW_LIMIT ||
 199             period < IOC4_CALIBRATE_HIGH_LIMIT) {
 200                 printk(KERN_INFO
 201                        "IOC4 %s: Clock calibration failed.  Assuming"
 202                        "PCI clock is %d ns.\n",
 203                        pci_name(idd->idd_pdev),
 204                        IOC4_CALIBRATE_DEFAULT / IOC4_EXTINT_COUNT_DIVISOR);
 205                 period = IOC4_CALIBRATE_DEFAULT;
 206         } else {
 207                 u64 ns = period;
 208
 209                 do_div(ns, IOC4_EXTINT_COUNT_DIVISOR);
 210                 printk(KERN_DEBUG
 211                        "IOC4 %s: PCI clock is %llu ns.\n",
 212                        pci_name(idd->idd_pdev), (unsigned long long)ns);
 213         }
 214
 215         /* Remember results.  We store the extint clock period rather
 216          * than the PCI clock period so that greater precision is
 217          * retained.  Divide by IOC4_EXTINT_COUNT_DIVISOR to get
 218          * PCI clock period.
 219          */
 220         idd->count_period = period;
 221 }
 222
 223 /* There are three variants of IOC4 cards: IO9, IO10, and PCI-RT.
 224  * Each brings out different combinations of IOC4 signals, thus.
 225  * the IOC4 subdrivers need to know to which we're attached.
 226  *
 227  * We look for the presence of a SCSI (IO9) or SATA (IO10) controller
 228  * on the same PCI bus at slot number 3 to differentiate IO9 from IO10.
 229  * If neither is present, it's a PCI-RT.
 230  */
 231 static unsigned int
 232 ioc4_variant(struct ioc4_driver_data *idd)
 233 {
 234         struct pci_dev *pdev = NULL;
 235         int found = 0;
 236
 237         /* IO9: Look for a QLogic ISP 12160 at the same bus and slot 3. */
 238         do {
 239                 pdev = pci_get_device(PCI_VENDOR_ID_QLOGIC,
 240                                       PCI_DEVICE_ID_QLOGIC_ISP12160, pdev);
 241                 if (pdev &&
 242                     idd->idd_pdev->bus->number == pdev->bus->number &&
 243                     3 == PCI_SLOT(pdev->devfn))
 244                         found = 1;
 245         } while (pdev && !found);
 246         if (NULL != pdev) {
 247                 pci_dev_put(pdev);
 248                 return IOC4_VARIANT_IO9;
 249         }
 250
 251         /* IO10: Look for a Vitesse VSC 7174 at the same bus and slot 3. */
 252         pdev = NULL;
 253         do {
 254                 pdev = pci_get_device(PCI_VENDOR_ID_VITESSE,
 255                                       PCI_DEVICE_ID_VITESSE_VSC7174, pdev);
 256                 if (pdev &&
 257                     idd->idd_pdev->bus->number == pdev->bus->number &&
 258                     3 == PCI_SLOT(pdev->devfn))
 259                         found = 1;
 260         } while (pdev && !found);
 261         if (NULL != pdev) {
 262                 pci_dev_put(pdev);
 263                 return IOC4_VARIANT_IO10;
 264         }
 265
 266         /* PCI-RT: No SCSI/SATA controller will be present */
 267         return IOC4_VARIANT_PCI_RT;
 268 }
 269
 270 static void
 271 ioc4_load_modules(struct work_struct *work)
 272 {
 273         request_module("sgiioc4");
 274 }
 275
 276 static DECLARE_WORK(ioc4_load_modules_work, ioc4_load_modules);
 277
 278 /* Adds a new instance of an IOC4 card */
 279 static int
 280 ioc4_probe(struct pci_dev *pdev, const struct pci_device_id *pci_id)
 281 {
 282         struct ioc4_driver_data *idd;
 283         struct ioc4_submodule *is;
 284         uint32_t pcmd;
 285         int ret;
 286
 287         /* Enable IOC4 and take ownership of it */
 288         if ((ret = pci_enable_device(pdev))) {
 289                 printk(KERN_WARNING
 290                        "%s: Failed to enable IOC4 device for pci_dev %s.\n",
 291                        __func__, pci_name(pdev));
 292                 goto out;
 293         }
 294         pci_set_master(pdev);
 295
 296         /* Set up per-IOC4 data */
 297         idd = kmalloc(sizeof(struct ioc4_driver_data), GFP_KERNEL);
 298         if (!idd) {
 299                 printk(KERN_WARNING
 300                        "%s: Failed to allocate IOC4 data for pci_dev %s.\n",
 301                        __func__, pci_name(pdev));
 302                 ret = -ENODEV;
 303                 goto out_idd;
 304         }
 305         idd->idd_pdev = pdev;
 306         idd->idd_pci_id = pci_id;
 307
 308         /* Map IOC4 misc registers.  These are shared between subdevices
 309          * so the main IOC4 module manages them.
 310          */
 311         idd->idd_bar0 = pci_resource_start(idd->idd_pdev, 0);
 312         if (!idd->idd_bar0) {
 313                 printk(KERN_WARNING
 314                        "%s: Unable to find IOC4 misc resource "
 315                        "for pci_dev %s.\n",
 316                        __func__, pci_name(idd->idd_pdev));
 317                 ret = -ENODEV;
 318                 goto out_pci;
 319         }
 320         if (!request_mem_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs),
 321                             "ioc4_misc")) {
 322                 printk(KERN_WARNING
 323                        "%s: Unable to request IOC4 misc region "
 324                        "for pci_dev %s.\n",
 325                        __func__, pci_name(idd->idd_pdev));
 326                 ret = -ENODEV;
 327                 goto out_pci;
 328         }
 329         idd->idd_misc_regs = ioremap(idd->idd_bar0,
 330                                      sizeof(struct ioc4_misc_regs));
 331         if (!idd->idd_misc_regs) {
 332                 printk(KERN_WARNING
 333                        "%s: Unable to remap IOC4 misc region "
 334                        "for pci_dev %s.\n",
 335                        __func__, pci_name(idd->idd_pdev));
 336                 ret = -ENODEV;
 337                 goto out_misc_region;
 338         }
 339
 340         /* Failsafe portion of per-IOC4 initialization */
 341
 342         /* Detect card variant */
 343         idd->idd_variant = ioc4_variant(idd);
 344         printk(KERN_INFO "IOC4 %s: %s card detected.\n", pci_name(pdev),
 345                idd->idd_variant == IOC4_VARIANT_IO9 ? "IO9" :
 346                idd->idd_variant == IOC4_VARIANT_PCI_RT ? "PCI-RT" :
 347                idd->idd_variant == IOC4_VARIANT_IO10 ? "IO10" : "unknown");
 348
 349         /* Initialize IOC4 */
 350         pci_read_config_dword(idd->idd_pdev, PCI_COMMAND, &pcmd);
 351         pci_write_config_dword(idd->idd_pdev, PCI_COMMAND,
 352                                pcmd | PCI_COMMAND_PARITY | PCI_COMMAND_SERR);
 353
 354         /* Determine PCI clock */
 355         ioc4_clock_calibrate(idd);
 356
 357         /* Disable/clear all interrupts.  Need to do this here lest
 358          * one submodule request the shared IOC4 IRQ, but interrupt
 359          * is generated by a different subdevice.
 360          */
 361         /* Disable */
 362         writel(~0, &idd->idd_misc_regs->other_iec.raw);
 363         writel(~0, &idd->idd_misc_regs->sio_iec);
 364         /* Clear (i.e. acknowledge) */
 365         writel(~0, &idd->idd_misc_regs->other_ir.raw);
 366         writel(~0, &idd->idd_misc_regs->sio_ir);
 367
 368         /* Track PCI-device specific data */
 369         idd->idd_serial_data = NULL;
 370         pci_set_drvdata(idd->idd_pdev, idd);
 371
 372         mutex_lock(&ioc4_mutex);
 373         list_add_tail(&idd->idd_list, &ioc4_devices);
 374
 375         /* Add this IOC4 to all submodules */
 376         list_for_each_entry(is, &ioc4_submodules, is_list) {
 377                 if (is->is_probe && is->is_probe(idd)) {
 378                         printk(KERN_WARNING
 379                                "%s: IOC4 submodule 0x%s probe failed "
 380                                "for pci_dev %s.\n",
 381                                __func__, module_name(is->is_owner),
 382                                pci_name(idd->idd_pdev));
 383                 }
 384         }
 385         mutex_unlock(&ioc4_mutex);
 386
 387         /* Request sgiioc4 IDE driver on boards that bring that functionality
 388          * off of IOC4.  The root filesystem may be hosted on a drive connected
 389          * to IOC4, so we need to make sure the sgiioc4 driver is loaded as it
 390          * won't be picked up by modprobes due to the ioc4 module owning the
 391          * PCI device.
 392          */
 393         if (idd->idd_variant != IOC4_VARIANT_PCI_RT) {
 394                 /* Request the module from a work procedure as the modprobe
 395                  * goes out to a userland helper and that will hang if done
 396                  * directly from ioc4_probe().
 397                  */
 398                 printk(KERN_INFO "IOC4 loading sgiioc4 submodule\n");
 399                 schedule_work(&ioc4_load_modules_work);
 400         }
 401
 402         return 0;
 403
 404 out_misc_region:
 405         release_mem_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs));
 406 out_pci:
 407         kfree(idd);
 408 out_idd:
 409         pci_disable_device(pdev);
 410 out:
 411         return ret;
 412 }
 413
 414 /* Removes a particular instance of an IOC4 card. */
 415 static void
 416 ioc4_remove(struct pci_dev *pdev)
 417 {
 418         struct ioc4_submodule *is;
 419         struct ioc4_driver_data *idd;
 420
 421         idd = pci_get_drvdata(pdev);
 422
 423         /* Remove this IOC4 from all submodules */
 424         mutex_lock(&ioc4_mutex);
 425         list_for_each_entry(is, &ioc4_submodules, is_list) {
 426                 if (is->is_remove && is->is_remove(idd)) {
 427                         printk(KERN_WARNING
 428                                "%s: IOC4 submodule 0x%s remove failed "
 429                                "for pci_dev %s.\n",
 430                                __func__, module_name(is->is_owner),
 431                                pci_name(idd->idd_pdev));
 432                 }
 433         }
 434         mutex_unlock(&ioc4_mutex);
 435
 436         /* Release resources */
 437         iounmap(idd->idd_misc_regs);
 438         if (!idd->idd_bar0) {
 439                 printk(KERN_WARNING
 440                        "%s: Unable to get IOC4 misc mapping for pci_dev %s. "
 441                        "Device removal may be incomplete.\n",
 442                        __func__, pci_name(idd->idd_pdev));
 443         }
 444         release_mem_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs));
 445
 446         /* Disable IOC4 and relinquish */
 447         pci_disable_device(pdev);
 448
 449         /* Remove and free driver data */
 450         mutex_lock(&ioc4_mutex);
 451         list_del(&idd->idd_list);
 452         mutex_unlock(&ioc4_mutex);
 453         kfree(idd);
 454 }
 455
 456 static struct pci_device_id ioc4_id_table[] = {
 457         {PCI_VENDOR_ID_SGI, PCI_DEVICE_ID_SGI_IOC4, PCI_ANY_ID,
 458          PCI_ANY_ID, 0x0b4000, 0xFFFFFF},
 459         {0}
 460 };
 461
 462 static struct pci_driver ioc4_driver = {
 463         .name = "IOC4",
 464         .id_table = ioc4_id_table,
 465         .probe = ioc4_probe,
 466         .remove = ioc4_remove,
 467 };
 468
 469 MODULE_DEVICE_TABLE(pci, ioc4_id_table);
 470
 471 /*********************
 472  * Module management *
 473  *********************/
 474
 475 /* Module load */
 476 static int __init
 477 ioc4_init(void)
 478 {
 479         return pci_register_driver(&ioc4_driver);
 480 }
 481
 482 /* Module unload */
 483 static void __exit
 484 ioc4_exit(void)
 485 {
 486         /* Ensure ioc4_load_modules() has completed before exiting */
 487         flush_work(&ioc4_load_modules_work);
 488         pci_unregister_driver(&ioc4_driver);
 489 }
 490
 491 module_init(ioc4_init);
 492 module_exit(ioc4_exit);
 493
 494 MODULE_AUTHOR("Brent Casavant - Silicon Graphics, Inc. <bcasavan@sgi.com>");
 495 MODULE_DESCRIPTION("PCI driver master module for SGI IOC4 Base-IO Card");
 496 MODULE_LICENSE("GPL");
 497
 498 EXPORT_SYMBOL(ioc4_register_submodule);
 499 EXPORT_SYMBOL(ioc4_unregister_submodule);