drivers/sn/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 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/mmtimer.h>
  33 #include <linux/rtc.h>
  34 #include <linux/rwsem.h>
  35 #include <asm/sn/addrs.h>
  36 #include <asm/sn/clksupport.h>
  37 #include <asm/sn/shub_mmr.h>
  38
  39 /***************
  40  * Definitions *
  41  ***************/
  42
  43 /* Tweakable values */
  44
  45 /* PCI bus speed detection/calibration */
  46 #define IOC4_CALIBRATE_COUNT 63 /* Calibration cycle period */
  47 #define IOC4_CALIBRATE_CYCLES 256       /* Average over this many cycles */
  48 #define IOC4_CALIBRATE_DISCARD 2        /* Discard first few cycles */
  49 #define IOC4_CALIBRATE_LOW_MHZ 25       /* Lower bound on bus speed sanity */
  50 #define IOC4_CALIBRATE_HIGH_MHZ 75      /* Upper bound on bus speed sanity */
  51 #define IOC4_CALIBRATE_DEFAULT_MHZ 66   /* Assumed if sanity check fails */
  52
  53 /************************
  54  * Submodule management *
  55  ************************/
  56
  57 static LIST_HEAD(ioc4_devices);
  58 static DECLARE_RWSEM(ioc4_devices_rwsem);
  59
  60 static LIST_HEAD(ioc4_submodules);
  61 static DECLARE_RWSEM(ioc4_submodules_rwsem);
  62
  63 /* Register an IOC4 submodule */
  64 int
  65 ioc4_register_submodule(struct ioc4_submodule *is)
  66 {
  67         struct ioc4_driver_data *idd;
  68
  69         down_write(&ioc4_submodules_rwsem);
  70         list_add(&is->is_list, &ioc4_submodules);
  71         up_write(&ioc4_submodules_rwsem);
  72
  73         /* Initialize submodule for each IOC4 */
  74         if (!is->is_probe)
  75                 return 0;
  76
  77         down_read(&ioc4_devices_rwsem);
  78         list_for_each_entry(idd, &ioc4_devices, idd_list) {
  79                 if (is->is_probe(idd)) {
  80                         printk(KERN_WARNING
  81                                "%s: IOC4 submodule %s probe failed "
  82                                "for pci_dev %s",
  83                                __FUNCTION__, module_name(is->is_owner),
  84                                pci_name(idd->idd_pdev));
  85                 }
  86         }
  87         up_read(&ioc4_devices_rwsem);
  88
  89         return 0;
  90 }
  91
  92 /* Unregister an IOC4 submodule */
  93 void
  94 ioc4_unregister_submodule(struct ioc4_submodule *is)
  95 {
  96         struct ioc4_driver_data *idd;
  97
  98         down_write(&ioc4_submodules_rwsem);
  99         list_del(&is->is_list);
 100         up_write(&ioc4_submodules_rwsem);
 101
 102         /* Remove submodule for each IOC4 */
 103         if (!is->is_remove)
 104                 return;
 105
 106         down_read(&ioc4_devices_rwsem);
 107         list_for_each_entry(idd, &ioc4_devices, idd_list) {
 108                 if (is->is_remove(idd)) {
 109                         printk(KERN_WARNING
 110                                "%s: IOC4 submodule %s remove failed "
 111                                "for pci_dev %s.\n",
 112                                __FUNCTION__, module_name(is->is_owner),
 113                                pci_name(idd->idd_pdev));
 114                 }
 115         }
 116         up_read(&ioc4_devices_rwsem);
 117 }
 118
 119 /*********************
 120  * Device management *
 121  *********************/
 122
 123 #define IOC4_CALIBRATE_LOW_LIMIT \
 124         (1000*IOC4_EXTINT_COUNT_DIVISOR/IOC4_CALIBRATE_LOW_MHZ)
 125 #define IOC4_CALIBRATE_HIGH_LIMIT \
 126         (1000*IOC4_EXTINT_COUNT_DIVISOR/IOC4_CALIBRATE_HIGH_MHZ)
 127 #define IOC4_CALIBRATE_DEFAULT \
 128         (1000*IOC4_EXTINT_COUNT_DIVISOR/IOC4_CALIBRATE_DEFAULT_MHZ)
 129
 130 #define IOC4_CALIBRATE_END \
 131         (IOC4_CALIBRATE_CYCLES + IOC4_CALIBRATE_DISCARD)
 132
 133 #define IOC4_INT_OUT_MODE_TOGGLE 0x7    /* Toggle INT_OUT every COUNT+1 ticks */
 134
 135 /* Determines external interrupt output clock period of the PCI bus an
 136  * IOC4 is attached to.  This value can be used to determine the PCI
 137  * bus speed.
 138  *
 139  * IOC4 has a design feature that various internal timers are derived from
 140  * the PCI bus clock.  This causes IOC4 device drivers to need to take the
 141  * bus speed into account when setting various register values (e.g. INT_OUT
 142  * register COUNT field, UART divisors, etc).  Since this information is
 143  * needed by several subdrivers, it is determined by the main IOC4 driver,
 144  * even though the following code utilizes external interrupt registers
 145  * to perform the speed calculation.
 146  */
 147 static void
 148 ioc4_clock_calibrate(struct ioc4_driver_data *idd)
 149 {
 150         extern unsigned long sn_rtc_cycles_per_second;
 151         union ioc4_int_out int_out;
 152         union ioc4_gpcr gpcr;
 153         unsigned int state, last_state = 1;
 154         uint64_t start = 0, end, period;
 155         unsigned int count = 0;
 156
 157         /* Enable output */
 158         gpcr.raw = 0;
 159         gpcr.fields.dir = IOC4_GPCR_DIR_0;
 160         gpcr.fields.int_out_en = 1;
 161         writel(gpcr.raw, &idd->idd_misc_regs->gpcr_s.raw);
 162
 163         /* Reset to power-on state */
 164         writel(0, &idd->idd_misc_regs->int_out.raw);
 165         mmiowb();
 166
 167         printk(KERN_INFO
 168                "%s: Calibrating PCI bus speed "
 169                "for pci_dev %s ... ", __FUNCTION__, pci_name(idd->idd_pdev));
 170         /* Set up square wave */
 171         int_out.raw = 0;
 172         int_out.fields.count = IOC4_CALIBRATE_COUNT;
 173         int_out.fields.mode = IOC4_INT_OUT_MODE_TOGGLE;
 174         int_out.fields.diag = 0;
 175         writel(int_out.raw, &idd->idd_misc_regs->int_out.raw);
 176         mmiowb();
 177
 178         /* Check square wave period averaged over some number of cycles */
 179         do {
 180                 int_out.raw = readl(&idd->idd_misc_regs->int_out.raw);
 181                 state = int_out.fields.int_out;
 182                 if (!last_state && state) {
 183                         count++;
 184                         if (count == IOC4_CALIBRATE_END) {
 185                                 end = rtc_time();
 186                                 break;
 187                         } else if (count == IOC4_CALIBRATE_DISCARD)
 188                                 start = rtc_time();
 189                 }
 190                 last_state = state;
 191         } while (1);
 192
 193         /* Calculation rearranged to preserve intermediate precision.
 194          * Logically:
 195          * 1. "end - start" gives us number of RTC cycles over all the
 196          *    square wave cycles measured.
 197          * 2. Divide by number of square wave cycles to get number of
 198          *    RTC cycles per square wave cycle.
 199          * 3. Divide by 2*(int_out.fields.count+1), which is the formula
 200          *    by which the IOC4 generates the square wave, to get the
 201          *    number of RTC cycles per IOC4 INT_OUT count.
 202          * 4. Divide by sn_rtc_cycles_per_second to get seconds per
 203          *    count.
 204          * 5. Multiply by 1E9 to get nanoseconds per count.
 205          */
 206         period = ((end - start) * 1000000000) /
 207             (IOC4_CALIBRATE_CYCLES * 2 * (IOC4_CALIBRATE_COUNT + 1)
 208              * sn_rtc_cycles_per_second);
 209
 210         /* Bounds check the result. */
 211         if (period > IOC4_CALIBRATE_LOW_LIMIT ||
 212             period < IOC4_CALIBRATE_HIGH_LIMIT) {
 213                 printk("failed. Assuming PCI clock ticks are %d ns.\n",
 214                        IOC4_CALIBRATE_DEFAULT / IOC4_EXTINT_COUNT_DIVISOR);
 215                 period = IOC4_CALIBRATE_DEFAULT;
 216         } else {
 217                 printk("succeeded. PCI clock ticks are %ld ns.\n",
 218                        period / IOC4_EXTINT_COUNT_DIVISOR);
 219         }
 220
 221         /* Remember results.  We store the extint clock period rather
 222          * than the PCI clock period so that greater precision is
 223          * retained.  Divide by IOC4_EXTINT_COUNT_DIVISOR to get
 224          * PCI clock period.
 225          */
 226         idd->count_period = period;
 227 }
 228
 229 /* Adds a new instance of an IOC4 card */
 230 static int
 231 ioc4_probe(struct pci_dev *pdev, const struct pci_device_id *pci_id)
 232 {
 233         struct ioc4_driver_data *idd;
 234         struct ioc4_submodule *is;
 235         uint32_t pcmd;
 236         int ret;
 237
 238         /* Enable IOC4 and take ownership of it */
 239         if ((ret = pci_enable_device(pdev))) {
 240                 printk(KERN_WARNING
 241                        "%s: Failed to enable IOC4 device for pci_dev %s.\n",
 242                        __FUNCTION__, pci_name(pdev));
 243                 goto out;
 244         }
 245         pci_set_master(pdev);
 246
 247         /* Set up per-IOC4 data */
 248         idd = kmalloc(sizeof(struct ioc4_driver_data), GFP_KERNEL);
 249         if (!idd) {
 250                 printk(KERN_WARNING
 251                        "%s: Failed to allocate IOC4 data for pci_dev %s.\n",
 252                        __FUNCTION__, pci_name(pdev));
 253                 ret = -ENODEV;
 254                 goto out_idd;
 255         }
 256         idd->idd_pdev = pdev;
 257         idd->idd_pci_id = pci_id;
 258
 259         /* Map IOC4 misc registers.  These are shared between subdevices
 260          * so the main IOC4 module manages them.
 261          */
 262         idd->idd_bar0 = pci_resource_start(idd->idd_pdev, 0);
 263         if (!idd->idd_bar0) {
 264                 printk(KERN_WARNING
 265                        "%s: Unable to find IOC4 misc resource "
 266                        "for pci_dev %s.\n",
 267                        __FUNCTION__, pci_name(idd->idd_pdev));
 268                 ret = -ENODEV;
 269                 goto out_pci;
 270         }
 271         if (!request_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs),
 272                             "ioc4_misc")) {
 273                 printk(KERN_WARNING
 274                        "%s: Unable to request IOC4 misc region "
 275                        "for pci_dev %s.\n",
 276                        __FUNCTION__, pci_name(idd->idd_pdev));
 277                 ret = -ENODEV;
 278                 goto out_pci;
 279         }
 280         idd->idd_misc_regs = ioremap(idd->idd_bar0,
 281                                      sizeof(struct ioc4_misc_regs));
 282         if (!idd->idd_misc_regs) {
 283                 printk(KERN_WARNING
 284                        "%s: Unable to remap IOC4 misc region "
 285                        "for pci_dev %s.\n",
 286                        __FUNCTION__, pci_name(idd->idd_pdev));
 287                 ret = -ENODEV;
 288                 goto out_misc_region;
 289         }
 290
 291         /* Failsafe portion of per-IOC4 initialization */
 292
 293         /* Initialize IOC4 */
 294         pci_read_config_dword(idd->idd_pdev, PCI_COMMAND, &pcmd);
 295         pci_write_config_dword(idd->idd_pdev, PCI_COMMAND,
 296                                pcmd | PCI_COMMAND_PARITY | PCI_COMMAND_SERR);
 297
 298         /* Determine PCI clock */
 299         ioc4_clock_calibrate(idd);
 300
 301         /* Disable/clear all interrupts.  Need to do this here lest
 302          * one submodule request the shared IOC4 IRQ, but interrupt
 303          * is generated by a different subdevice.
 304          */
 305         /* Disable */
 306         writel(~0, &idd->idd_misc_regs->other_iec.raw);
 307         writel(~0, &idd->idd_misc_regs->sio_iec);
 308         /* Clear (i.e. acknowledge) */
 309         writel(~0, &idd->idd_misc_regs->other_ir.raw);
 310         writel(~0, &idd->idd_misc_regs->sio_ir);
 311
 312         /* Track PCI-device specific data */
 313         idd->idd_serial_data = NULL;
 314         pci_set_drvdata(idd->idd_pdev, idd);
 315         down_write(&ioc4_devices_rwsem);
 316         list_add(&idd->idd_list, &ioc4_devices);
 317         up_write(&ioc4_devices_rwsem);
 318
 319         /* Add this IOC4 to all submodules */
 320         down_read(&ioc4_submodules_rwsem);
 321         list_for_each_entry(is, &ioc4_submodules, is_list) {
 322                 if (is->is_probe && is->is_probe(idd)) {
 323                         printk(KERN_WARNING
 324                                "%s: IOC4 submodule 0x%s probe failed "
 325                                "for pci_dev %s.\n",
 326                                __FUNCTION__, module_name(is->is_owner),
 327                                pci_name(idd->idd_pdev));
 328                 }
 329         }
 330         up_read(&ioc4_submodules_rwsem);
 331
 332         return 0;
 333
 334 out_misc_region:
 335         release_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs));
 336 out_pci:
 337         kfree(idd);
 338 out_idd:
 339         pci_disable_device(pdev);
 340 out:
 341         return ret;
 342 }
 343
 344 /* Removes a particular instance of an IOC4 card. */
 345 static void
 346 ioc4_remove(struct pci_dev *pdev)
 347 {
 348         struct ioc4_submodule *is;
 349         struct ioc4_driver_data *idd;
 350
 351         idd = pci_get_drvdata(pdev);
 352
 353         /* Remove this IOC4 from all submodules */
 354         down_read(&ioc4_submodules_rwsem);
 355         list_for_each_entry(is, &ioc4_submodules, is_list) {
 356                 if (is->is_remove && is->is_remove(idd)) {
 357                         printk(KERN_WARNING
 358                                "%s: IOC4 submodule 0x%s remove failed "
 359                                "for pci_dev %s.\n",
 360                                __FUNCTION__, module_name(is->is_owner),
 361                                pci_name(idd->idd_pdev));
 362                 }
 363         }
 364         up_read(&ioc4_submodules_rwsem);
 365
 366         /* Release resources */
 367         iounmap(idd->idd_misc_regs);
 368         if (!idd->idd_bar0) {
 369                 printk(KERN_WARNING
 370                        "%s: Unable to get IOC4 misc mapping for pci_dev %s. "
 371                        "Device removal may be incomplete.\n",
 372                        __FUNCTION__, pci_name(idd->idd_pdev));
 373         }
 374         release_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs));
 375
 376         /* Disable IOC4 and relinquish */
 377         pci_disable_device(pdev);
 378
 379         /* Remove and free driver data */
 380         down_write(&ioc4_devices_rwsem);
 381         list_del(&idd->idd_list);
 382         up_write(&ioc4_devices_rwsem);
 383         kfree(idd);
 384 }
 385
 386 static struct pci_device_id ioc4_id_table[] = {
 387         {PCI_VENDOR_ID_SGI, PCI_DEVICE_ID_SGI_IOC4, PCI_ANY_ID,
 388          PCI_ANY_ID, 0x0b4000, 0xFFFFFF},
 389         {0}
 390 };
 391
 392 static struct pci_driver __devinitdata ioc4_driver = {
 393         .name = "IOC4",
 394         .id_table = ioc4_id_table,
 395         .probe = ioc4_probe,
 396         .remove = ioc4_remove,
 397 };
 398
 399 MODULE_DEVICE_TABLE(pci, ioc4_id_table);
 400
 401 /*********************
 402  * Module management *
 403  *********************/
 404
 405 /* Module load */
 406 static int __devinit
 407 ioc4_init(void)
 408 {
 409         return pci_register_driver(&ioc4_driver);
 410 }
 411
 412 /* Module unload */
 413 static void __devexit
 414 ioc4_exit(void)
 415 {
 416         pci_unregister_driver(&ioc4_driver);
 417 }
 418
 419 module_init(ioc4_init);
 420 module_exit(ioc4_exit);
 421
 422 MODULE_AUTHOR("Brent Casavant - Silicon Graphics, Inc. <bcasavan@sgi.com>");
 423 MODULE_DESCRIPTION("PCI driver master module for SGI IOC4 Base-IO Card");
 424 MODULE_LICENSE("GPL");
 425
 426 EXPORT_SYMBOL(ioc4_register_submodule);
 427 EXPORT_SYMBOL(ioc4_unregister_submodule);