1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2008 Poul-Henning Kamp 5 * Copyright (c) 2010 Alexander Motin <mav@FreeBSD.org> 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * $FreeBSD$ 30 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD$"); 34 35 #include "opt_isa.h" 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/bus.h> 40 #include <sys/clock.h> 41 #include <sys/lock.h> 42 #include <sys/mutex.h> 43 #include <sys/kdb.h> 44 #include <sys/kernel.h> 45 #include <sys/module.h> 46 #include <sys/proc.h> 47 #include <sys/rman.h> 48 #include <sys/timeet.h> 49 50 #include <isa/rtc.h> 51 #ifdef DEV_ISA 52 #include <isa/isareg.h> 53 #include <isa/isavar.h> 54 #endif 55 #include <machine/intr_machdep.h> 56 #include "clock_if.h" 57 #include <contrib/dev/acpica/include/acpi.h> 58 #include <machine/md_var.h> 59 60 /* 61 * atrtc_lock protects low-level access to individual hardware registers. 62 * atrtc_time_lock protects the entire sequence of accessing multiple registers 63 * to read or write the date and time. 64 */ 65 static struct mtx atrtc_lock; 66 MTX_SYSINIT(atrtc_lock_init, &atrtc_lock, "atrtc", MTX_SPIN); 67 68 /* Force RTC enabled/disabled. */ 69 static int atrtc_enabled = -1; 70 TUNABLE_INT("hw.atrtc.enabled", &atrtc_enabled); 71 72 struct mtx atrtc_time_lock; 73 MTX_SYSINIT(atrtc_time_lock_init, &atrtc_time_lock, "atrtc_time", MTX_DEF); 74 75 int atrtcclock_disable = 0; 76 77 static int rtc_reg = -1; 78 static u_char rtc_statusa = RTCSA_DIVIDER | RTCSA_NOPROF; 79 static u_char rtc_statusb = RTCSB_24HR; 80 81 /* 82 * RTC support routines 83 */ 84 85 static inline u_char 86 rtcin_locked(int reg) 87 { 88 89 if (rtc_reg != reg) { 90 inb(0x84); 91 outb(IO_RTC, reg); 92 rtc_reg = reg; 93 inb(0x84); 94 } 95 return (inb(IO_RTC + 1)); 96 } 97 98 static inline void 99 rtcout_locked(int reg, u_char val) 100 { 101 102 if (rtc_reg != reg) { 103 inb(0x84); 104 outb(IO_RTC, reg); 105 rtc_reg = reg; 106 inb(0x84); 107 } 108 outb(IO_RTC + 1, val); 109 inb(0x84); 110 } 111 112 int 113 rtcin(int reg) 114 { 115 u_char val; 116 117 mtx_lock_spin(&atrtc_lock); 118 val = rtcin_locked(reg); 119 mtx_unlock_spin(&atrtc_lock); 120 return (val); 121 } 122 123 void 124 writertc(int reg, u_char val) 125 { 126 127 mtx_lock_spin(&atrtc_lock); 128 rtcout_locked(reg, val); 129 mtx_unlock_spin(&atrtc_lock); 130 } 131 132 static void 133 atrtc_start(void) 134 { 135 136 mtx_lock_spin(&atrtc_lock); 137 rtcout_locked(RTC_STATUSA, rtc_statusa); 138 rtcout_locked(RTC_STATUSB, RTCSB_24HR); 139 mtx_unlock_spin(&atrtc_lock); 140 } 141 142 static void 143 atrtc_rate(unsigned rate) 144 { 145 146 rtc_statusa = RTCSA_DIVIDER | rate; 147 writertc(RTC_STATUSA, rtc_statusa); 148 } 149 150 static void 151 atrtc_enable_intr(void) 152 { 153 154 rtc_statusb |= RTCSB_PINTR; 155 mtx_lock_spin(&atrtc_lock); 156 rtcout_locked(RTC_STATUSB, rtc_statusb); 157 rtcin_locked(RTC_INTR); 158 mtx_unlock_spin(&atrtc_lock); 159 } 160 161 static void 162 atrtc_disable_intr(void) 163 { 164 165 rtc_statusb &= ~RTCSB_PINTR; 166 mtx_lock_spin(&atrtc_lock); 167 rtcout_locked(RTC_STATUSB, rtc_statusb); 168 rtcin_locked(RTC_INTR); 169 mtx_unlock_spin(&atrtc_lock); 170 } 171 172 void 173 atrtc_restore(void) 174 { 175 176 /* Restore all of the RTC's "status" (actually, control) registers. */ 177 mtx_lock_spin(&atrtc_lock); 178 rtcin_locked(RTC_STATUSA); /* dummy to get rtc_reg set */ 179 rtcout_locked(RTC_STATUSB, RTCSB_24HR); 180 rtcout_locked(RTC_STATUSA, rtc_statusa); 181 rtcout_locked(RTC_STATUSB, rtc_statusb); 182 rtcin_locked(RTC_INTR); 183 mtx_unlock_spin(&atrtc_lock); 184 } 185 186 /********************************************************************** 187 * RTC driver for subr_rtc 188 */ 189 190 struct atrtc_softc { 191 int port_rid, intr_rid; 192 struct resource *port_res; 193 struct resource *intr_res; 194 void *intr_handler; 195 struct eventtimer et; 196 }; 197 198 static int 199 rtc_start(struct eventtimer *et, sbintime_t first, sbintime_t period) 200 { 201 202 atrtc_rate(max(fls(period + (period >> 1)) - 17, 1)); 203 atrtc_enable_intr(); 204 return (0); 205 } 206 207 static int 208 rtc_stop(struct eventtimer *et) 209 { 210 211 atrtc_disable_intr(); 212 return (0); 213 } 214 215 /* 216 * This routine receives statistical clock interrupts from the RTC. 217 * As explained above, these occur at 128 interrupts per second. 218 * When profiling, we receive interrupts at a rate of 1024 Hz. 219 * 220 * This does not actually add as much overhead as it sounds, because 221 * when the statistical clock is active, the hardclock driver no longer 222 * needs to keep (inaccurate) statistics on its own. This decouples 223 * statistics gathering from scheduling interrupts. 224 * 225 * The RTC chip requires that we read status register C (RTC_INTR) 226 * to acknowledge an interrupt, before it will generate the next one. 227 * Under high interrupt load, rtcintr() can be indefinitely delayed and 228 * the clock can tick immediately after the read from RTC_INTR. In this 229 * case, the mc146818A interrupt signal will not drop for long enough 230 * to register with the 8259 PIC. If an interrupt is missed, the stat 231 * clock will halt, considerably degrading system performance. This is 232 * why we use 'while' rather than a more straightforward 'if' below. 233 * Stat clock ticks can still be lost, causing minor loss of accuracy 234 * in the statistics, but the stat clock will no longer stop. 235 */ 236 static int 237 rtc_intr(void *arg) 238 { 239 struct atrtc_softc *sc = (struct atrtc_softc *)arg; 240 int flag = 0; 241 242 while (rtcin(RTC_INTR) & RTCIR_PERIOD) { 243 flag = 1; 244 if (sc->et.et_active) 245 sc->et.et_event_cb(&sc->et, sc->et.et_arg); 246 } 247 return(flag ? FILTER_HANDLED : FILTER_STRAY); 248 } 249 250 /* 251 * Attach to the ISA PnP descriptors for the timer and realtime clock. 252 */ 253 static struct isa_pnp_id atrtc_ids[] = { 254 { 0x000bd041 /* PNP0B00 */, "AT realtime clock" }, 255 { 0 } 256 }; 257 258 static bool 259 atrtc_acpi_disabled(void) 260 { 261 uint16_t flags; 262 263 if (!acpi_get_fadt_bootflags(&flags)) 264 return (false); 265 return ((flags & ACPI_FADT_NO_CMOS_RTC) != 0); 266 return (true); 267 } 268 269 static int 270 atrtc_probe(device_t dev) 271 { 272 int result; 273 274 if ((atrtc_enabled == -1 && atrtc_acpi_disabled()) || 275 (atrtc_enabled == 0)) 276 return (ENXIO); 277 278 result = ISA_PNP_PROBE(device_get_parent(dev), dev, atrtc_ids); 279 /* ENOENT means no PnP-ID, device is hinted. */ 280 if (result == ENOENT) { 281 device_set_desc(dev, "AT realtime clock"); 282 return (BUS_PROBE_LOW_PRIORITY); 283 } 284 return (result); 285 } 286 287 static int 288 atrtc_attach(device_t dev) 289 { 290 struct atrtc_softc *sc; 291 rman_res_t s; 292 int i; 293 294 sc = device_get_softc(dev); 295 sc->port_res = bus_alloc_resource(dev, SYS_RES_IOPORT, &sc->port_rid, 296 IO_RTC, IO_RTC + 1, 2, RF_ACTIVE); 297 if (sc->port_res == NULL) 298 device_printf(dev, "Warning: Couldn't map I/O.\n"); 299 atrtc_start(); 300 clock_register(dev, 1000000); 301 bzero(&sc->et, sizeof(struct eventtimer)); 302 if (!atrtcclock_disable && 303 (resource_int_value(device_get_name(dev), device_get_unit(dev), 304 "clock", &i) != 0 || i != 0)) { 305 sc->intr_rid = 0; 306 while (bus_get_resource(dev, SYS_RES_IRQ, sc->intr_rid, 307 &s, NULL) == 0 && s != 8) 308 sc->intr_rid++; 309 sc->intr_res = bus_alloc_resource(dev, SYS_RES_IRQ, 310 &sc->intr_rid, 8, 8, 1, RF_ACTIVE); 311 if (sc->intr_res == NULL) { 312 device_printf(dev, "Can't map interrupt.\n"); 313 return (0); 314 } else if ((bus_setup_intr(dev, sc->intr_res, INTR_TYPE_CLK, 315 rtc_intr, NULL, sc, &sc->intr_handler))) { 316 device_printf(dev, "Can't setup interrupt.\n"); 317 return (0); 318 } else { 319 /* Bind IRQ to BSP to avoid live migration. */ 320 bus_bind_intr(dev, sc->intr_res, 0); 321 } 322 sc->et.et_name = "RTC"; 323 sc->et.et_flags = ET_FLAGS_PERIODIC | ET_FLAGS_POW2DIV; 324 sc->et.et_quality = 0; 325 sc->et.et_frequency = 32768; 326 sc->et.et_min_period = 0x00080000; 327 sc->et.et_max_period = 0x80000000; 328 sc->et.et_start = rtc_start; 329 sc->et.et_stop = rtc_stop; 330 sc->et.et_priv = dev; 331 et_register(&sc->et); 332 } 333 return(0); 334 } 335 336 static int 337 atrtc_resume(device_t dev) 338 { 339 340 atrtc_restore(); 341 return(0); 342 } 343 344 static int 345 atrtc_settime(device_t dev __unused, struct timespec *ts) 346 { 347 struct bcd_clocktime bct; 348 349 clock_ts_to_bcd(ts, &bct, false); 350 clock_dbgprint_bcd(dev, CLOCK_DBG_WRITE, &bct); 351 352 mtx_lock(&atrtc_time_lock); 353 mtx_lock_spin(&atrtc_lock); 354 355 /* Disable RTC updates and interrupts. */ 356 rtcout_locked(RTC_STATUSB, RTCSB_HALT | RTCSB_24HR); 357 358 /* Write all the time registers. */ 359 rtcout_locked(RTC_SEC, bct.sec); 360 rtcout_locked(RTC_MIN, bct.min); 361 rtcout_locked(RTC_HRS, bct.hour); 362 rtcout_locked(RTC_WDAY, bct.dow + 1); 363 rtcout_locked(RTC_DAY, bct.day); 364 rtcout_locked(RTC_MONTH, bct.mon); 365 rtcout_locked(RTC_YEAR, bct.year & 0xff); 366 #ifdef USE_RTC_CENTURY 367 rtcout_locked(RTC_CENTURY, bct.year >> 8); 368 #endif 369 370 /* 371 * Re-enable RTC updates and interrupts. 372 */ 373 rtcout_locked(RTC_STATUSB, rtc_statusb); 374 rtcin_locked(RTC_INTR); 375 376 mtx_unlock_spin(&atrtc_lock); 377 mtx_unlock(&atrtc_time_lock); 378 379 return (0); 380 } 381 382 static int 383 atrtc_gettime(device_t dev, struct timespec *ts) 384 { 385 struct bcd_clocktime bct; 386 387 /* Look if we have a RTC present and the time is valid */ 388 if (!(rtcin(RTC_STATUSD) & RTCSD_PWR)) { 389 device_printf(dev, "WARNING: Battery failure indication\n"); 390 return (EINVAL); 391 } 392 393 /* 394 * wait for time update to complete 395 * If RTCSA_TUP is zero, we have at least 244us before next update. 396 * This is fast enough on most hardware, but a refinement would be 397 * to make sure that no more than 240us pass after we start reading, 398 * and try again if so. 399 */ 400 mtx_lock(&atrtc_time_lock); 401 while (rtcin(RTC_STATUSA) & RTCSA_TUP) 402 continue; 403 mtx_lock_spin(&atrtc_lock); 404 bct.sec = rtcin_locked(RTC_SEC); 405 bct.min = rtcin_locked(RTC_MIN); 406 bct.hour = rtcin_locked(RTC_HRS); 407 bct.day = rtcin_locked(RTC_DAY); 408 bct.mon = rtcin_locked(RTC_MONTH); 409 bct.year = rtcin_locked(RTC_YEAR); 410 #ifdef USE_RTC_CENTURY 411 bct.year |= rtcin_locked(RTC_CENTURY) << 8; 412 #endif 413 mtx_unlock_spin(&atrtc_lock); 414 mtx_unlock(&atrtc_time_lock); 415 /* dow is unused in timespec conversion and we have no nsec info. */ 416 bct.dow = 0; 417 bct.nsec = 0; 418 clock_dbgprint_bcd(dev, CLOCK_DBG_READ, &bct); 419 return (clock_bcd_to_ts(&bct, ts, false)); 420 } 421 422 static device_method_t atrtc_methods[] = { 423 /* Device interface */ 424 DEVMETHOD(device_probe, atrtc_probe), 425 DEVMETHOD(device_attach, atrtc_attach), 426 DEVMETHOD(device_detach, bus_generic_detach), 427 DEVMETHOD(device_shutdown, bus_generic_shutdown), 428 DEVMETHOD(device_suspend, bus_generic_suspend), 429 /* XXX stop statclock? */ 430 DEVMETHOD(device_resume, atrtc_resume), 431 432 /* clock interface */ 433 DEVMETHOD(clock_gettime, atrtc_gettime), 434 DEVMETHOD(clock_settime, atrtc_settime), 435 436 { 0, 0 } 437 }; 438 439 static driver_t atrtc_driver = { 440 "atrtc", 441 atrtc_methods, 442 sizeof(struct atrtc_softc), 443 }; 444 445 static devclass_t atrtc_devclass; 446 447 DRIVER_MODULE(atrtc, isa, atrtc_driver, atrtc_devclass, 0, 0); 448 DRIVER_MODULE(atrtc, acpi, atrtc_driver, atrtc_devclass, 0, 0); 449 ISA_PNP_INFO(atrtc_ids); 450