drivers/rtc/rtc-mrst.c

   1 /*
   2  * rtc-mrst.c: Driver for Moorestown virtual RTC
   3  *
   4  * (C) Copyright 2009 Intel Corporation
   5  * Author: Jacob Pan (jacob.jun.pan@intel.com)
   6  *         Feng Tang (feng.tang@intel.com)
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License
  10  * as published by the Free Software Foundation; version 2
  11  * of the License.
  12  *
  13  * Note:
  14  * VRTC is emulated by system controller firmware, the real HW
  15  * RTC is located in the PMIC device. SCU FW shadows PMIC RTC
  16  * in a memory mapped IO space that is visible to the host IA
  17  * processor.
  18  *
  19  * This driver is based upon drivers/rtc/rtc-cmos.c
  20  */
  21
  22 /*
  23  * Note:
  24  *  * vRTC only supports binary mode and 24H mode
  25  *  * vRTC only support PIE and AIE, no UIE, and its PIE only happens
  26  *    at 23:59:59pm everyday, no support for adjustable frequency
  27  *  * Alarm function is also limited to hr/min/sec.
  28  */
  29
  30 #include <linux/mod_devicetable.h>
  31 #include <linux/platform_device.h>
  32 #include <linux/interrupt.h>
  33 #include <linux/spinlock.h>
  34 #include <linux/kernel.h>
  35 #include <linux/module.h>
  36 #include <linux/init.h>
  37 #include <linux/sfi.h>
  38
  39 #include <asm-generic/rtc.h>
  40 #include <asm/intel_scu_ipc.h>
  41 #include <asm/mrst.h>
  42 #include <asm/mrst-vrtc.h>
  43
  44 struct mrst_rtc {
  45         struct rtc_device       *rtc;
  46         struct device           *dev;
  47         int                     irq;
  48         struct resource         *iomem;
  49
  50         u8                      enabled_wake;
  51         u8                      suspend_ctrl;
  52 };
  53
  54 static const char driver_name[] = "rtc_mrst";
  55
  56 #define RTC_IRQMASK     (RTC_PF | RTC_AF)
  57
  58 static inline int is_intr(u8 rtc_intr)
  59 {
  60         if (!(rtc_intr & RTC_IRQF))
  61                 return 0;
  62         return rtc_intr & RTC_IRQMASK;
  63 }
  64
  65 static inline unsigned char vrtc_is_updating(void)
  66 {
  67         unsigned char uip;
  68         unsigned long flags;
  69
  70         spin_lock_irqsave(&rtc_lock, flags);
  71         uip = (vrtc_cmos_read(RTC_FREQ_SELECT) & RTC_UIP);
  72         spin_unlock_irqrestore(&rtc_lock, flags);
  73         return uip;
  74 }
  75
  76 /*
  77  * rtc_time's year contains the increment over 1900, but vRTC's YEAR
  78  * register can't be programmed to value larger than 0x64, so vRTC
  79  * driver chose to use 1960 (1970 is UNIX time start point) as the base,
  80  * and does the translation at read/write time.
  81  *
  82  * Why not just use 1970 as the offset? it's because using 1960 will
  83  * make it consistent in leap year setting for both vrtc and low-level
  84  * physical rtc devices.
  85  */
  86 static int mrst_read_time(struct device *dev, struct rtc_time *time)
  87 {
  88         unsigned long flags;
  89
  90         if (vrtc_is_updating())
  91                 mdelay(20);
  92
  93         spin_lock_irqsave(&rtc_lock, flags);
  94         time->tm_sec = vrtc_cmos_read(RTC_SECONDS);
  95         time->tm_min = vrtc_cmos_read(RTC_MINUTES);
  96         time->tm_hour = vrtc_cmos_read(RTC_HOURS);
  97         time->tm_mday = vrtc_cmos_read(RTC_DAY_OF_MONTH);
  98         time->tm_mon = vrtc_cmos_read(RTC_MONTH);
  99         time->tm_year = vrtc_cmos_read(RTC_YEAR);
 100         spin_unlock_irqrestore(&rtc_lock, flags);
 101
 102         /* Adjust for the 1960/1900 */
 103         time->tm_year += 60;
 104         time->tm_mon--;
 105         return RTC_24H;
 106 }
 107
 108 static int mrst_set_time(struct device *dev, struct rtc_time *time)
 109 {
 110         int ret;
 111         unsigned long flags;
 112         unsigned char mon, day, hrs, min, sec;
 113         unsigned int yrs;
 114
 115         yrs = time->tm_year;
 116         mon = time->tm_mon + 1;   /* tm_mon starts at zero */
 117         day = time->tm_mday;
 118         hrs = time->tm_hour;
 119         min = time->tm_min;
 120         sec = time->tm_sec;
 121
 122         if (yrs < 70 || yrs > 138)
 123                 return -EINVAL;
 124         yrs -= 60;
 125
 126         spin_lock_irqsave(&rtc_lock, flags);
 127
 128         vrtc_cmos_write(yrs, RTC_YEAR);
 129         vrtc_cmos_write(mon, RTC_MONTH);
 130         vrtc_cmos_write(day, RTC_DAY_OF_MONTH);
 131         vrtc_cmos_write(hrs, RTC_HOURS);
 132         vrtc_cmos_write(min, RTC_MINUTES);
 133         vrtc_cmos_write(sec, RTC_SECONDS);
 134
 135         spin_unlock_irqrestore(&rtc_lock, flags);
 136
 137         ret = intel_scu_ipc_simple_command(IPCMSG_VRTC, IPC_CMD_VRTC_SETTIME);
 138         return ret;
 139 }
 140
 141 static int mrst_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 142 {
 143         struct mrst_rtc *mrst = dev_get_drvdata(dev);
 144         unsigned char rtc_control;
 145
 146         if (mrst->irq <= 0)
 147                 return -EIO;
 148
 149         /* Basic alarms only support hour, minute, and seconds fields.
 150          * Some also support day and month, for alarms up to a year in
 151          * the future.
 152          */
 153         t->time.tm_mday = -1;
 154         t->time.tm_mon = -1;
 155         t->time.tm_year = -1;
 156
 157         /* vRTC only supports binary mode */
 158         spin_lock_irq(&rtc_lock);
 159         t->time.tm_sec = vrtc_cmos_read(RTC_SECONDS_ALARM);
 160         t->time.tm_min = vrtc_cmos_read(RTC_MINUTES_ALARM);
 161         t->time.tm_hour = vrtc_cmos_read(RTC_HOURS_ALARM);
 162
 163         rtc_control = vrtc_cmos_read(RTC_CONTROL);
 164         spin_unlock_irq(&rtc_lock);
 165
 166         t->enabled = !!(rtc_control & RTC_AIE);
 167         t->pending = 0;
 168
 169         return 0;
 170 }
 171
 172 static void mrst_checkintr(struct mrst_rtc *mrst, unsigned char rtc_control)
 173 {
 174         unsigned char   rtc_intr;
 175
 176         /*
 177          * NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
 178          * allegedly some older rtcs need that to handle irqs properly
 179          */
 180         rtc_intr = vrtc_cmos_read(RTC_INTR_FLAGS);
 181         rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 182         if (is_intr(rtc_intr))
 183                 rtc_update_irq(mrst->rtc, 1, rtc_intr);
 184 }
 185
 186 static void mrst_irq_enable(struct mrst_rtc *mrst, unsigned char mask)
 187 {
 188         unsigned char   rtc_control;
 189
 190         /*
 191          * Flush any pending IRQ status, notably for update irqs,
 192          * before we enable new IRQs
 193          */
 194         rtc_control = vrtc_cmos_read(RTC_CONTROL);
 195         mrst_checkintr(mrst, rtc_control);
 196
 197         rtc_control |= mask;
 198         vrtc_cmos_write(rtc_control, RTC_CONTROL);
 199
 200         mrst_checkintr(mrst, rtc_control);
 201 }
 202
 203 static void mrst_irq_disable(struct mrst_rtc *mrst, unsigned char mask)
 204 {
 205         unsigned char   rtc_control;
 206
 207         rtc_control = vrtc_cmos_read(RTC_CONTROL);
 208         rtc_control &= ~mask;
 209         vrtc_cmos_write(rtc_control, RTC_CONTROL);
 210         mrst_checkintr(mrst, rtc_control);
 211 }
 212
 213 static int mrst_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 214 {
 215         struct mrst_rtc *mrst = dev_get_drvdata(dev);
 216         unsigned char hrs, min, sec;
 217         int ret = 0;
 218
 219         if (!mrst->irq)
 220                 return -EIO;
 221
 222         hrs = t->time.tm_hour;
 223         min = t->time.tm_min;
 224         sec = t->time.tm_sec;
 225
 226         spin_lock_irq(&rtc_lock);
 227         /* Next rtc irq must not be from previous alarm setting */
 228         mrst_irq_disable(mrst, RTC_AIE);
 229
 230         /* Update alarm */
 231         vrtc_cmos_write(hrs, RTC_HOURS_ALARM);
 232         vrtc_cmos_write(min, RTC_MINUTES_ALARM);
 233         vrtc_cmos_write(sec, RTC_SECONDS_ALARM);
 234
 235         spin_unlock_irq(&rtc_lock);
 236
 237         ret = intel_scu_ipc_simple_command(IPCMSG_VRTC, IPC_CMD_VRTC_SETALARM);
 238         if (ret)
 239                 return ret;
 240
 241         spin_lock_irq(&rtc_lock);
 242         if (t->enabled)
 243                 mrst_irq_enable(mrst, RTC_AIE);
 244
 245         spin_unlock_irq(&rtc_lock);
 246
 247         return 0;
 248 }
 249
 250 /* Currently, the vRTC doesn't support UIE ON/OFF */
 251 static int mrst_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 252 {
 253         struct mrst_rtc *mrst = dev_get_drvdata(dev);
 254         unsigned long   flags;
 255
 256         spin_lock_irqsave(&rtc_lock, flags);
 257         if (enabled)
 258                 mrst_irq_enable(mrst, RTC_AIE);
 259         else
 260                 mrst_irq_disable(mrst, RTC_AIE);
 261         spin_unlock_irqrestore(&rtc_lock, flags);
 262         return 0;
 263 }
 264
 265
 266 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
 267
 268 static int mrst_procfs(struct device *dev, struct seq_file *seq)
 269 {
 270         unsigned char   rtc_control, valid;
 271
 272         spin_lock_irq(&rtc_lock);
 273         rtc_control = vrtc_cmos_read(RTC_CONTROL);
 274         valid = vrtc_cmos_read(RTC_VALID);
 275         spin_unlock_irq(&rtc_lock);
 276
 277         return seq_printf(seq,
 278                         "periodic_IRQ\t: %s\n"
 279                         "alarm\t\t: %s\n"
 280                         "BCD\t\t: no\n"
 281                         "periodic_freq\t: daily (not adjustable)\n",
 282                         (rtc_control & RTC_PIE) ? "on" : "off",
 283                         (rtc_control & RTC_AIE) ? "on" : "off");
 284 }
 285
 286 #else
 287 #define mrst_procfs     NULL
 288 #endif
 289
 290 static const struct rtc_class_ops mrst_rtc_ops = {
 291         .read_time      = mrst_read_time,
 292         .set_time       = mrst_set_time,
 293         .read_alarm     = mrst_read_alarm,
 294         .set_alarm      = mrst_set_alarm,
 295         .proc           = mrst_procfs,
 296         .alarm_irq_enable = mrst_rtc_alarm_irq_enable,
 297 };
 298
 299 static struct mrst_rtc  mrst_rtc;
 300
 301 /*
 302  * When vRTC IRQ is captured by SCU FW, FW will clear the AIE bit in
 303  * Reg B, so no need for this driver to clear it
 304  */
 305 static irqreturn_t mrst_rtc_irq(int irq, void *p)
 306 {
 307         u8 irqstat;
 308
 309         spin_lock(&rtc_lock);
 310         /* This read will clear all IRQ flags inside Reg C */
 311         irqstat = vrtc_cmos_read(RTC_INTR_FLAGS);
 312         spin_unlock(&rtc_lock);
 313
 314         irqstat &= RTC_IRQMASK | RTC_IRQF;
 315         if (is_intr(irqstat)) {
 316                 rtc_update_irq(p, 1, irqstat);
 317                 return IRQ_HANDLED;
 318         }
 319         return IRQ_NONE;
 320 }
 321
 322 static int __devinit
 323 vrtc_mrst_do_probe(struct device *dev, struct resource *iomem, int rtc_irq)
 324 {
 325         int retval = 0;
 326         unsigned char rtc_control;
 327
 328         /* There can be only one ... */
 329         if (mrst_rtc.dev)
 330                 return -EBUSY;
 331
 332         if (!iomem)
 333                 return -ENODEV;
 334
 335         iomem = request_mem_region(iomem->start,
 336                         iomem->end + 1 - iomem->start,
 337                         driver_name);
 338         if (!iomem) {
 339                 dev_dbg(dev, "i/o mem already in use.\n");
 340                 return -EBUSY;
 341         }
 342
 343         mrst_rtc.irq = rtc_irq;
 344         mrst_rtc.iomem = iomem;
 345         mrst_rtc.dev = dev;
 346         dev_set_drvdata(dev, &mrst_rtc);
 347
 348         mrst_rtc.rtc = rtc_device_register(driver_name, dev,
 349                                 &mrst_rtc_ops, THIS_MODULE);
 350         if (IS_ERR(mrst_rtc.rtc)) {
 351                 retval = PTR_ERR(mrst_rtc.rtc);
 352                 goto cleanup0;
 353         }
 354
 355         rename_region(iomem, dev_name(&mrst_rtc.rtc->dev));
 356
 357         spin_lock_irq(&rtc_lock);
 358         mrst_irq_disable(&mrst_rtc, RTC_PIE | RTC_AIE);
 359         rtc_control = vrtc_cmos_read(RTC_CONTROL);
 360         spin_unlock_irq(&rtc_lock);
 361
 362         if (!(rtc_control & RTC_24H) || (rtc_control & (RTC_DM_BINARY)))
 363                 dev_dbg(dev, "TODO: support more than 24-hr BCD mode\n");
 364
 365         if (rtc_irq) {
 366                 retval = request_irq(rtc_irq, mrst_rtc_irq,
 367                                 IRQF_DISABLED, dev_name(&mrst_rtc.rtc->dev),
 368                                 mrst_rtc.rtc);
 369                 if (retval < 0) {
 370                         dev_dbg(dev, "IRQ %d is already in use, err %d\n",
 371                                 rtc_irq, retval);
 372                         goto cleanup1;
 373                 }
 374         }
 375         dev_dbg(dev, "initialised\n");
 376         return 0;
 377
 378 cleanup1:
 379         rtc_device_unregister(mrst_rtc.rtc);
 380 cleanup0:
 381         dev_set_drvdata(dev, NULL);
 382         mrst_rtc.dev = NULL;
 383         release_region(iomem->start, iomem->end + 1 - iomem->start);
 384         dev_err(dev, "rtc-mrst: unable to initialise\n");
 385         return retval;
 386 }
 387
 388 static void rtc_mrst_do_shutdown(void)
 389 {
 390         spin_lock_irq(&rtc_lock);
 391         mrst_irq_disable(&mrst_rtc, RTC_IRQMASK);
 392         spin_unlock_irq(&rtc_lock);
 393 }
 394
 395 static void __devexit rtc_mrst_do_remove(struct device *dev)
 396 {
 397         struct mrst_rtc *mrst = dev_get_drvdata(dev);
 398         struct resource *iomem;
 399
 400         rtc_mrst_do_shutdown();
 401
 402         if (mrst->irq)
 403                 free_irq(mrst->irq, mrst->rtc);
 404
 405         rtc_device_unregister(mrst->rtc);
 406         mrst->rtc = NULL;
 407
 408         iomem = mrst->iomem;
 409         release_region(iomem->start, iomem->end + 1 - iomem->start);
 410         mrst->iomem = NULL;
 411
 412         mrst->dev = NULL;
 413         dev_set_drvdata(dev, NULL);
 414 }
 415
 416 #ifdef  CONFIG_PM
 417 static int mrst_suspend(struct device *dev, pm_message_t mesg)
 418 {
 419         struct mrst_rtc *mrst = dev_get_drvdata(dev);
 420         unsigned char   tmp;
 421
 422         /* Only the alarm might be a wakeup event source */
 423         spin_lock_irq(&rtc_lock);
 424         mrst->suspend_ctrl = tmp = vrtc_cmos_read(RTC_CONTROL);
 425         if (tmp & (RTC_PIE | RTC_AIE)) {
 426                 unsigned char   mask;
 427
 428                 if (device_may_wakeup(dev))
 429                         mask = RTC_IRQMASK & ~RTC_AIE;
 430                 else
 431                         mask = RTC_IRQMASK;
 432                 tmp &= ~mask;
 433                 vrtc_cmos_write(tmp, RTC_CONTROL);
 434
 435                 mrst_checkintr(mrst, tmp);
 436         }
 437         spin_unlock_irq(&rtc_lock);
 438
 439         if (tmp & RTC_AIE) {
 440                 mrst->enabled_wake = 1;
 441                 enable_irq_wake(mrst->irq);
 442         }
 443
 444         dev_dbg(&mrst_rtc.rtc->dev, "suspend%s, ctrl %02x\n",
 445                         (tmp & RTC_AIE) ? ", alarm may wake" : "",
 446                         tmp);
 447
 448         return 0;
 449 }
 450
 451 /*
 452  * We want RTC alarms to wake us from the deep power saving state
 453  */
 454 static inline int mrst_poweroff(struct device *dev)
 455 {
 456         return mrst_suspend(dev, PMSG_HIBERNATE);
 457 }
 458
 459 static int mrst_resume(struct device *dev)
 460 {
 461         struct mrst_rtc *mrst = dev_get_drvdata(dev);
 462         unsigned char tmp = mrst->suspend_ctrl;
 463
 464         /* Re-enable any irqs previously active */
 465         if (tmp & RTC_IRQMASK) {
 466                 unsigned char   mask;
 467
 468                 if (mrst->enabled_wake) {
 469                         disable_irq_wake(mrst->irq);
 470                         mrst->enabled_wake = 0;
 471                 }
 472
 473                 spin_lock_irq(&rtc_lock);
 474                 do {
 475                         vrtc_cmos_write(tmp, RTC_CONTROL);
 476
 477                         mask = vrtc_cmos_read(RTC_INTR_FLAGS);
 478                         mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
 479                         if (!is_intr(mask))
 480                                 break;
 481
 482                         rtc_update_irq(mrst->rtc, 1, mask);
 483                         tmp &= ~RTC_AIE;
 484                 } while (mask & RTC_AIE);
 485                 spin_unlock_irq(&rtc_lock);
 486         }
 487
 488         dev_dbg(&mrst_rtc.rtc->dev, "resume, ctrl %02x\n", tmp);
 489
 490         return 0;
 491 }
 492
 493 #else
 494 #define mrst_suspend    NULL
 495 #define mrst_resume     NULL
 496
 497 static inline int mrst_poweroff(struct device *dev)
 498 {
 499         return -ENOSYS;
 500 }
 501
 502 #endif
 503
 504 static int __devinit vrtc_mrst_platform_probe(struct platform_device *pdev)
 505 {
 506         return vrtc_mrst_do_probe(&pdev->dev,
 507                         platform_get_resource(pdev, IORESOURCE_MEM, 0),
 508                         platform_get_irq(pdev, 0));
 509 }
 510
 511 static int __devexit vrtc_mrst_platform_remove(struct platform_device *pdev)
 512 {
 513         rtc_mrst_do_remove(&pdev->dev);
 514         return 0;
 515 }
 516
 517 static void vrtc_mrst_platform_shutdown(struct platform_device *pdev)
 518 {
 519         if (system_state == SYSTEM_POWER_OFF && !mrst_poweroff(&pdev->dev))
 520                 return;
 521
 522         rtc_mrst_do_shutdown();
 523 }
 524
 525 MODULE_ALIAS("platform:vrtc_mrst");
 526
 527 static struct platform_driver vrtc_mrst_platform_driver = {
 528         .probe          = vrtc_mrst_platform_probe,
 529         .remove         = __devexit_p(vrtc_mrst_platform_remove),
 530         .shutdown       = vrtc_mrst_platform_shutdown,
 531         .driver = {
 532                 .name           = (char *) driver_name,
 533                 .suspend        = mrst_suspend,
 534                 .resume         = mrst_resume,
 535         }
 536 };
 537
 538 static int __init vrtc_mrst_init(void)
 539 {
 540         return platform_driver_register(&vrtc_mrst_platform_driver);
 541 }
 542
 543 static void __exit vrtc_mrst_exit(void)
 544 {
 545         platform_driver_unregister(&vrtc_mrst_platform_driver);
 546 }
 547
 548 module_init(vrtc_mrst_init);
 549 module_exit(vrtc_mrst_exit);
 550
 551 MODULE_AUTHOR("Jacob Pan; Feng Tang");
 552 MODULE_DESCRIPTION("Driver for Moorestown virtual RTC");
 553 MODULE_LICENSE("GPL");