linux/drivers/misc/ioc4.c
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   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
  55static DEFINE_MUTEX(ioc4_mutex);
  56
  57static LIST_HEAD(ioc4_devices);
  58static LIST_HEAD(ioc4_submodules);
  59
  60/* Register an IOC4 submodule */
  61int
  62ioc4_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 */
  88void
  89ioc4_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 */
 141static void
 142ioc4_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 */
 233static unsigned int
 234ioc4_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/* Adds a new instance of an IOC4 card */
 273static int
 274ioc4_probe(struct pci_dev *pdev, const struct pci_device_id *pci_id)
 275{
 276        struct ioc4_driver_data *idd;
 277        struct ioc4_submodule *is;
 278        uint32_t pcmd;
 279        int ret;
 280
 281        /* Enable IOC4 and take ownership of it */
 282        if ((ret = pci_enable_device(pdev))) {
 283                printk(KERN_WARNING
 284                       "%s: Failed to enable IOC4 device for pci_dev %s.\n",
 285                       __func__, pci_name(pdev));
 286                goto out;
 287        }
 288        pci_set_master(pdev);
 289
 290        /* Set up per-IOC4 data */
 291        idd = kmalloc(sizeof(struct ioc4_driver_data), GFP_KERNEL);
 292        if (!idd) {
 293                printk(KERN_WARNING
 294                       "%s: Failed to allocate IOC4 data for pci_dev %s.\n",
 295                       __func__, pci_name(pdev));
 296                ret = -ENODEV;
 297                goto out_idd;
 298        }
 299        idd->idd_pdev = pdev;
 300        idd->idd_pci_id = pci_id;
 301
 302        /* Map IOC4 misc registers.  These are shared between subdevices
 303         * so the main IOC4 module manages them.
 304         */
 305        idd->idd_bar0 = pci_resource_start(idd->idd_pdev, 0);
 306        if (!idd->idd_bar0) {
 307                printk(KERN_WARNING
 308                       "%s: Unable to find IOC4 misc resource "
 309                       "for pci_dev %s.\n",
 310                       __func__, pci_name(idd->idd_pdev));
 311                ret = -ENODEV;
 312                goto out_pci;
 313        }
 314        if (!request_mem_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs),
 315                            "ioc4_misc")) {
 316                printk(KERN_WARNING
 317                       "%s: Unable to request IOC4 misc region "
 318                       "for pci_dev %s.\n",
 319                       __func__, pci_name(idd->idd_pdev));
 320                ret = -ENODEV;
 321                goto out_pci;
 322        }
 323        idd->idd_misc_regs = ioremap(idd->idd_bar0,
 324                                     sizeof(struct ioc4_misc_regs));
 325        if (!idd->idd_misc_regs) {
 326                printk(KERN_WARNING
 327                       "%s: Unable to remap IOC4 misc region "
 328                       "for pci_dev %s.\n",
 329                       __func__, pci_name(idd->idd_pdev));
 330                ret = -ENODEV;
 331                goto out_misc_region;
 332        }
 333
 334        /* Failsafe portion of per-IOC4 initialization */
 335
 336        /* Detect card variant */
 337        idd->idd_variant = ioc4_variant(idd);
 338        printk(KERN_INFO "IOC4 %s: %s card detected.\n", pci_name(pdev),
 339               idd->idd_variant == IOC4_VARIANT_IO9 ? "IO9" :
 340               idd->idd_variant == IOC4_VARIANT_PCI_RT ? "PCI-RT" :
 341               idd->idd_variant == IOC4_VARIANT_IO10 ? "IO10" : "unknown");
 342
 343        /* Initialize IOC4 */
 344        pci_read_config_dword(idd->idd_pdev, PCI_COMMAND, &pcmd);
 345        pci_write_config_dword(idd->idd_pdev, PCI_COMMAND,
 346                               pcmd | PCI_COMMAND_PARITY | PCI_COMMAND_SERR);
 347
 348        /* Determine PCI clock */
 349        ioc4_clock_calibrate(idd);
 350
 351        /* Disable/clear all interrupts.  Need to do this here lest
 352         * one submodule request the shared IOC4 IRQ, but interrupt
 353         * is generated by a different subdevice.
 354         */
 355        /* Disable */
 356        writel(~0, &idd->idd_misc_regs->other_iec.raw);
 357        writel(~0, &idd->idd_misc_regs->sio_iec);
 358        /* Clear (i.e. acknowledge) */
 359        writel(~0, &idd->idd_misc_regs->other_ir.raw);
 360        writel(~0, &idd->idd_misc_regs->sio_ir);
 361
 362        /* Track PCI-device specific data */
 363        idd->idd_serial_data = NULL;
 364        pci_set_drvdata(idd->idd_pdev, idd);
 365
 366        mutex_lock(&ioc4_mutex);
 367        list_add_tail(&idd->idd_list, &ioc4_devices);
 368
 369        /* Add this IOC4 to all submodules */
 370        list_for_each_entry(is, &ioc4_submodules, is_list) {
 371                if (is->is_probe && is->is_probe(idd)) {
 372                        printk(KERN_WARNING
 373                               "%s: IOC4 submodule 0x%s probe failed "
 374                               "for pci_dev %s.\n",
 375                               __func__, module_name(is->is_owner),
 376                               pci_name(idd->idd_pdev));
 377                }
 378        }
 379        mutex_unlock(&ioc4_mutex);
 380
 381        return 0;
 382
 383out_misc_region:
 384        release_mem_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs));
 385out_pci:
 386        kfree(idd);
 387out_idd:
 388        pci_disable_device(pdev);
 389out:
 390        return ret;
 391}
 392
 393/* Removes a particular instance of an IOC4 card. */
 394static void
 395ioc4_remove(struct pci_dev *pdev)
 396{
 397        struct ioc4_submodule *is;
 398        struct ioc4_driver_data *idd;
 399
 400        idd = pci_get_drvdata(pdev);
 401
 402        /* Remove this IOC4 from all submodules */
 403        mutex_lock(&ioc4_mutex);
 404        list_for_each_entry(is, &ioc4_submodules, is_list) {
 405                if (is->is_remove && is->is_remove(idd)) {
 406                        printk(KERN_WARNING
 407                               "%s: IOC4 submodule 0x%s remove failed "
 408                               "for pci_dev %s.\n",
 409                               __func__, module_name(is->is_owner),
 410                               pci_name(idd->idd_pdev));
 411                }
 412        }
 413        mutex_unlock(&ioc4_mutex);
 414
 415        /* Release resources */
 416        iounmap(idd->idd_misc_regs);
 417        if (!idd->idd_bar0) {
 418                printk(KERN_WARNING
 419                       "%s: Unable to get IOC4 misc mapping for pci_dev %s. "
 420                       "Device removal may be incomplete.\n",
 421                       __func__, pci_name(idd->idd_pdev));
 422        }
 423        release_mem_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs));
 424
 425        /* Disable IOC4 and relinquish */
 426        pci_disable_device(pdev);
 427
 428        /* Remove and free driver data */
 429        mutex_lock(&ioc4_mutex);
 430        list_del(&idd->idd_list);
 431        mutex_unlock(&ioc4_mutex);
 432        kfree(idd);
 433}
 434
 435static struct pci_device_id ioc4_id_table[] = {
 436        {PCI_VENDOR_ID_SGI, PCI_DEVICE_ID_SGI_IOC4, PCI_ANY_ID,
 437         PCI_ANY_ID, 0x0b4000, 0xFFFFFF},
 438        {0}
 439};
 440
 441static struct pci_driver ioc4_driver = {
 442        .name = "IOC4",
 443        .id_table = ioc4_id_table,
 444        .probe = ioc4_probe,
 445        .remove = ioc4_remove,
 446};
 447
 448MODULE_DEVICE_TABLE(pci, ioc4_id_table);
 449
 450/*********************
 451 * Module management *
 452 *********************/
 453
 454/* Module load */
 455static int __devinit
 456ioc4_init(void)
 457{
 458        return pci_register_driver(&ioc4_driver);
 459}
 460
 461/* Module unload */
 462static void __devexit
 463ioc4_exit(void)
 464{
 465        pci_unregister_driver(&ioc4_driver);
 466}
 467
 468module_init(ioc4_init);
 469module_exit(ioc4_exit);
 470
 471MODULE_AUTHOR("Brent Casavant - Silicon Graphics, Inc. <bcasavan@sgi.com>");
 472MODULE_DESCRIPTION("PCI driver master module for SGI IOC4 Base-IO Card");
 473MODULE_LICENSE("GPL");
 474
 475EXPORT_SYMBOL(ioc4_register_submodule);
 476EXPORT_SYMBOL(ioc4_unregister_submodule);
 477
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