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         struct timespec start_ts, end_ts;
 149         uint64_t start, end, period;
 150         unsigned int count = 0;
 151
 152         /* Enable output */
 153         gpcr.raw = 0;
 154         gpcr.fields.dir = IOC4_GPCR_DIR_0;
 155         gpcr.fields.int_out_en = 1;
 156         writel(gpcr.raw, &idd->idd_misc_regs->gpcr_s.raw);
 157
 158         /* Reset to power-on state */
 159         writel(0, &idd->idd_misc_regs->int_out.raw);
 160         mmiowb();
 161
 162         /* Set up square wave */
 163         int_out.raw = 0;
 164         int_out.fields.count = IOC4_CALIBRATE_COUNT;
 165         int_out.fields.mode = IOC4_INT_OUT_MODE_TOGGLE;
 166         int_out.fields.diag = 0;
 167         writel(int_out.raw, &idd->idd_misc_regs->int_out.raw);
 168         mmiowb();
 169
 170         /* Check square wave period averaged over some number of cycles */
 171         do {
 172                 int_out.raw = readl(&idd->idd_misc_regs->int_out.raw);
 173                 state = int_out.fields.int_out;
 174                 if (!last_state && state) {
 175                         count++;
 176                         if (count == IOC4_CALIBRATE_END) {
 177                                 ktime_get_ts(&end_ts);
 178                                 break;
 179                         } else if (count == IOC4_CALIBRATE_DISCARD)
 180                                 ktime_get_ts(&start_ts);
 181                 }
 182                 last_state = state;
 183         } while (1);
 184
 185         /* Calculation rearranged to preserve intermediate precision.
 186          * Logically:
 187          * 1. "end - start" gives us the measurement period over all
 188          *    the square wave cycles.
 189          * 2. Divide by number of square wave cycles to get the period
 190          *    of a square wave cycle.
 191          * 3. Divide by 2*(int_out.fields.count+1), which is the formula
 192          *    by which the IOC4 generates the square wave, to get the
 193          *    period of an IOC4 INT_OUT count.
 194          */
 195         end = end_ts.tv_sec * NSEC_PER_SEC + end_ts.tv_nsec;
 196         start = start_ts.tv_sec * NSEC_PER_SEC + start_ts.tv_nsec;
 197         period = (end - start) /
 198                 (IOC4_CALIBRATE_CYCLES * 2 * (IOC4_CALIBRATE_COUNT + 1));
 199
 200         /* Bounds check the result. */
 201         if (period > IOC4_CALIBRATE_LOW_LIMIT ||
 202             period < IOC4_CALIBRATE_HIGH_LIMIT) {
 203                 printk(KERN_INFO
 204                        "IOC4 %s: Clock calibration failed.  Assuming"
 205                        "PCI clock is %d ns.\n",
 206                        pci_name(idd->idd_pdev),
 207                        IOC4_CALIBRATE_DEFAULT / IOC4_EXTINT_COUNT_DIVISOR);
 208                 period = IOC4_CALIBRATE_DEFAULT;
 209         } else {
 210                 u64 ns = period;
 211
 212                 do_div(ns, IOC4_EXTINT_COUNT_DIVISOR);
 213                 printk(KERN_DEBUG
 214                        "IOC4 %s: PCI clock is %llu ns.\n",
 215                        pci_name(idd->idd_pdev), (unsigned long long)ns);
 216         }
 217
 218         /* Remember results.  We store the extint clock period rather
 219          * than the PCI clock period so that greater precision is
 220          * retained.  Divide by IOC4_EXTINT_COUNT_DIVISOR to get
 221          * PCI clock period.
 222          */
 223         idd->count_period = period;
 224 }
 225
 226 /* There are three variants of IOC4 cards: IO9, IO10, and PCI-RT.
 227  * Each brings out different combinations of IOC4 signals, thus.
 228  * the IOC4 subdrivers need to know to which we're attached.
 229  *
 230  * We look for the presence of a SCSI (IO9) or SATA (IO10) controller
 231  * on the same PCI bus at slot number 3 to differentiate IO9 from IO10.
 232  * If neither is present, it's a PCI-RT.
 233  */
 234 static unsigned int
 235 ioc4_variant(struct ioc4_driver_data *idd)
 236 {
 237         struct pci_dev *pdev = NULL;
 238         int found = 0;
 239
 240         /* IO9: Look for a QLogic ISP 12160 at the same bus and slot 3. */
 241         do {
 242                 pdev = pci_get_device(PCI_VENDOR_ID_QLOGIC,
 243                                       PCI_DEVICE_ID_QLOGIC_ISP12160, pdev);
 244                 if (pdev &&
 245                     idd->idd_pdev->bus->number == pdev->bus->number &&
 246                     3 == PCI_SLOT(pdev->devfn))
 247                         found = 1;
 248         } while (pdev && !found);
 249         if (NULL != pdev) {
 250                 pci_dev_put(pdev);
 251                 return IOC4_VARIANT_IO9;
 252         }
 253
 254         /* IO10: Look for a Vitesse VSC 7174 at the same bus and slot 3. */
 255         pdev = NULL;
 256         do {
 257                 pdev = pci_get_device(PCI_VENDOR_ID_VITESSE,
 258                                       PCI_DEVICE_ID_VITESSE_VSC7174, pdev);
 259                 if (pdev &&
 260                     idd->idd_pdev->bus->number == pdev->bus->number &&
 261                     3 == PCI_SLOT(pdev->devfn))
 262                         found = 1;
 263         } while (pdev && !found);
 264         if (NULL != pdev) {
 265                 pci_dev_put(pdev);
 266                 return IOC4_VARIANT_IO10;
 267         }
 268
 269         /* PCI-RT: No SCSI/SATA controller will be present */
 270         return IOC4_VARIANT_PCI_RT;
 271 }
 272
 273 static void
 274 ioc4_load_modules(struct work_struct *work)
 275 {
 276         request_module("sgiioc4");
 277 }
 278
 279 static DECLARE_WORK(ioc4_load_modules_work, ioc4_load_modules);
 280
 281 /* Adds a new instance of an IOC4 card */
 282 static int
 283 ioc4_probe(struct pci_dev *pdev, const struct pci_device_id *pci_id)
 284 {
 285         struct ioc4_driver_data *idd;
 286         struct ioc4_submodule *is;
 287         uint32_t pcmd;
 288         int ret;
 289
 290         /* Enable IOC4 and take ownership of it */
 291         if ((ret = pci_enable_device(pdev))) {
 292                 printk(KERN_WARNING
 293                        "%s: Failed to enable IOC4 device for pci_dev %s.\n",
 294                        __func__, pci_name(pdev));
 295                 goto out;
 296         }
 297         pci_set_master(pdev);
 298
 299         /* Set up per-IOC4 data */
 300         idd = kmalloc(sizeof(struct ioc4_driver_data), GFP_KERNEL);
 301         if (!idd) {
 302                 printk(KERN_WARNING
 303                        "%s: Failed to allocate IOC4 data for pci_dev %s.\n",
 304                        __func__, pci_name(pdev));
 305                 ret = -ENODEV;
 306                 goto out_idd;
 307         }
 308         idd->idd_pdev = pdev;
 309         idd->idd_pci_id = pci_id;
 310
 311         /* Map IOC4 misc registers.  These are shared between subdevices
 312          * so the main IOC4 module manages them.
 313          */
 314         idd->idd_bar0 = pci_resource_start(idd->idd_pdev, 0);
 315         if (!idd->idd_bar0) {
 316                 printk(KERN_WARNING
 317                        "%s: Unable to find IOC4 misc resource "
 318                        "for pci_dev %s.\n",
 319                        __func__, pci_name(idd->idd_pdev));
 320                 ret = -ENODEV;
 321                 goto out_pci;
 322         }
 323         if (!request_mem_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs),
 324                             "ioc4_misc")) {
 325                 printk(KERN_WARNING
 326                        "%s: Unable to request IOC4 misc region "
 327                        "for pci_dev %s.\n",
 328                        __func__, pci_name(idd->idd_pdev));
 329                 ret = -ENODEV;
 330                 goto out_pci;
 331         }
 332         idd->idd_misc_regs = ioremap(idd->idd_bar0,
 333                                      sizeof(struct ioc4_misc_regs));
 334         if (!idd->idd_misc_regs) {
 335                 printk(KERN_WARNING
 336                        "%s: Unable to remap IOC4 misc region "
 337                        "for pci_dev %s.\n",
 338                        __func__, pci_name(idd->idd_pdev));
 339                 ret = -ENODEV;
 340                 goto out_misc_region;
 341         }
 342
 343         /* Failsafe portion of per-IOC4 initialization */
 344
 345         /* Detect card variant */
 346         idd->idd_variant = ioc4_variant(idd);
 347         printk(KERN_INFO "IOC4 %s: %s card detected.\n", pci_name(pdev),
 348                idd->idd_variant == IOC4_VARIANT_IO9 ? "IO9" :
 349                idd->idd_variant == IOC4_VARIANT_PCI_RT ? "PCI-RT" :
 350                idd->idd_variant == IOC4_VARIANT_IO10 ? "IO10" : "unknown");
 351
 352         /* Initialize IOC4 */
 353         pci_read_config_dword(idd->idd_pdev, PCI_COMMAND, &pcmd);
 354         pci_write_config_dword(idd->idd_pdev, PCI_COMMAND,
 355                                pcmd | PCI_COMMAND_PARITY | PCI_COMMAND_SERR);
 356
 357         /* Determine PCI clock */
 358         ioc4_clock_calibrate(idd);
 359
 360         /* Disable/clear all interrupts.  Need to do this here lest
 361          * one submodule request the shared IOC4 IRQ, but interrupt
 362          * is generated by a different subdevice.
 363          */
 364         /* Disable */
 365         writel(~0, &idd->idd_misc_regs->other_iec.raw);
 366         writel(~0, &idd->idd_misc_regs->sio_iec);
 367         /* Clear (i.e. acknowledge) */
 368         writel(~0, &idd->idd_misc_regs->other_ir.raw);
 369         writel(~0, &idd->idd_misc_regs->sio_ir);
 370
 371         /* Track PCI-device specific data */
 372         idd->idd_serial_data = NULL;
 373         pci_set_drvdata(idd->idd_pdev, idd);
 374
 375         mutex_lock(&ioc4_mutex);
 376         list_add_tail(&idd->idd_list, &ioc4_devices);
 377
 378         /* Add this IOC4 to all submodules */
 379         list_for_each_entry(is, &ioc4_submodules, is_list) {
 380                 if (is->is_probe && is->is_probe(idd)) {
 381                         printk(KERN_WARNING
 382                                "%s: IOC4 submodule 0x%s probe failed "
 383                                "for pci_dev %s.\n",
 384                                __func__, module_name(is->is_owner),
 385                                pci_name(idd->idd_pdev));
 386                 }
 387         }
 388         mutex_unlock(&ioc4_mutex);
 389
 390         /* Request sgiioc4 IDE driver on boards that bring that functionality
 391          * off of IOC4.  The root filesystem may be hosted on a drive connected
 392          * to IOC4, so we need to make sure the sgiioc4 driver is loaded as it
 393          * won't be picked up by modprobes due to the ioc4 module owning the
 394          * PCI device.
 395          */
 396         if (idd->idd_variant != IOC4_VARIANT_PCI_RT) {
 397                 /* Request the module from a work procedure as the modprobe
 398                  * goes out to a userland helper and that will hang if done
 399                  * directly from ioc4_probe().
 400                  */
 401                 printk(KERN_INFO "IOC4 loading sgiioc4 submodule\n");
 402                 schedule_work(&ioc4_load_modules_work);
 403         }
 404
 405         return 0;
 406
 407 out_misc_region:
 408         release_mem_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs));
 409 out_pci:
 410         kfree(idd);
 411 out_idd:
 412         pci_disable_device(pdev);
 413 out:
 414         return ret;
 415 }
 416
 417 /* Removes a particular instance of an IOC4 card. */
 418 static void
 419 ioc4_remove(struct pci_dev *pdev)
 420 {
 421         struct ioc4_submodule *is;
 422         struct ioc4_driver_data *idd;
 423
 424         idd = pci_get_drvdata(pdev);
 425
 426         /* Remove this IOC4 from all submodules */
 427         mutex_lock(&ioc4_mutex);
 428         list_for_each_entry(is, &ioc4_submodules, is_list) {
 429                 if (is->is_remove && is->is_remove(idd)) {
 430                         printk(KERN_WARNING
 431                                "%s: IOC4 submodule 0x%s remove failed "
 432                                "for pci_dev %s.\n",
 433                                __func__, module_name(is->is_owner),
 434                                pci_name(idd->idd_pdev));
 435                 }
 436         }
 437         mutex_unlock(&ioc4_mutex);
 438
 439         /* Release resources */
 440         iounmap(idd->idd_misc_regs);
 441         if (!idd->idd_bar0) {
 442                 printk(KERN_WARNING
 443                        "%s: Unable to get IOC4 misc mapping for pci_dev %s. "
 444                        "Device removal may be incomplete.\n",
 445                        __func__, pci_name(idd->idd_pdev));
 446         }
 447         release_mem_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs));
 448
 449         /* Disable IOC4 and relinquish */
 450         pci_disable_device(pdev);
 451
 452         /* Remove and free driver data */
 453         mutex_lock(&ioc4_mutex);
 454         list_del(&idd->idd_list);
 455         mutex_unlock(&ioc4_mutex);
 456         kfree(idd);
 457 }
 458
 459 static struct pci_device_id ioc4_id_table[] = {
 460         {PCI_VENDOR_ID_SGI, PCI_DEVICE_ID_SGI_IOC4, PCI_ANY_ID,
 461          PCI_ANY_ID, 0x0b4000, 0xFFFFFF},
 462         {0}
 463 };
 464
 465 static struct pci_driver ioc4_driver = {
 466         .name = "IOC4",
 467         .id_table = ioc4_id_table,
 468         .probe = ioc4_probe,
 469         .remove = ioc4_remove,
 470 };
 471
 472 MODULE_DEVICE_TABLE(pci, ioc4_id_table);
 473
 474 /*********************
 475  * Module management *
 476  *********************/
 477
 478 /* Module load */
 479 static int __init
 480 ioc4_init(void)
 481 {
 482         return pci_register_driver(&ioc4_driver);
 483 }
 484
 485 /* Module unload */
 486 static void __exit
 487 ioc4_exit(void)
 488 {
 489         /* Ensure ioc4_load_modules() has completed before exiting */
 490         flush_work(&ioc4_load_modules_work);
 491         pci_unregister_driver(&ioc4_driver);
 492 }
 493
 494 module_init(ioc4_init);
 495 module_exit(ioc4_exit);
 496
 497 MODULE_AUTHOR("Brent Casavant - Silicon Graphics, Inc. <bcasavan@sgi.com>");
 498 MODULE_DESCRIPTION("PCI driver master module for SGI IOC4 Base-IO Card");
 499 MODULE_LICENSE("GPL");
 500
 501 EXPORT_SYMBOL(ioc4_register_submodule);
 502 EXPORT_SYMBOL(ioc4_unregister_submodule);