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 58 /* 59 * clock_lock protects low-level access to individual hardware registers. 60 * atrtc_time_lock protects the entire sequence of accessing multiple registers 61 * to read or write the date and time. 62 */ 63 #define RTC_LOCK do { if (!kdb_active) mtx_lock_spin(&clock_lock); } while (0) 64 #define RTC_UNLOCK do { if (!kdb_active) mtx_unlock_spin(&clock_lock); } while (0) 65 66 struct mtx atrtc_time_lock; 67 MTX_SYSINIT(atrtc_lock_init, &atrtc_time_lock, "atrtc", MTX_DEF); 68 69 int atrtcclock_disable = 0; 70 71 static int rtc_reg = -1; 72 static u_char rtc_statusa = RTCSA_DIVIDER | RTCSA_NOPROF; 73 static u_char rtc_statusb = RTCSB_24HR; 74 75 /* 76 * RTC support routines 77 */ 78 79 static inline u_char 80 rtcin_locked(int reg) 81 { 82 83 if (rtc_reg != reg) { 84 inb(0x84); 85 outb(IO_RTC, reg); 86 rtc_reg = reg; 87 inb(0x84); 88 } 89 return (inb(IO_RTC + 1)); 90 } 91 92 static inline void 93 rtcout_locked(int reg, u_char val) 94 { 95 96 if (rtc_reg != reg) { 97 inb(0x84); 98 outb(IO_RTC, reg); 99 rtc_reg = reg; 100 inb(0x84); 101 } 102 outb(IO_RTC + 1, val); 103 inb(0x84); 104 } 105 106 int 107 rtcin(int reg) 108 { 109 u_char val; 110 111 RTC_LOCK; 112 val = rtcin_locked(reg); 113 RTC_UNLOCK; 114 return (val); 115 } 116 117 void 118 writertc(int reg, u_char val) 119 { 120 121 RTC_LOCK; 122 rtcout_locked(reg, val); 123 RTC_UNLOCK; 124 } 125 126 static void 127 atrtc_start(void) 128 { 129 130 writertc(RTC_STATUSA, rtc_statusa); 131 writertc(RTC_STATUSB, RTCSB_24HR); 132 } 133 134 static void 135 atrtc_rate(unsigned rate) 136 { 137 138 rtc_statusa = RTCSA_DIVIDER | rate; 139 writertc(RTC_STATUSA, rtc_statusa); 140 } 141 142 static void 143 atrtc_enable_intr(void) 144 { 145 146 rtc_statusb |= RTCSB_PINTR; 147 writertc(RTC_STATUSB, rtc_statusb); 148 rtcin(RTC_INTR); 149 } 150 151 static void 152 atrtc_disable_intr(void) 153 { 154 155 rtc_statusb &= ~RTCSB_PINTR; 156 writertc(RTC_STATUSB, rtc_statusb); 157 rtcin(RTC_INTR); 158 } 159 160 void 161 atrtc_restore(void) 162 { 163 164 /* Restore all of the RTC's "status" (actually, control) registers. */ 165 rtcin(RTC_STATUSA); /* dummy to get rtc_reg set */ 166 writertc(RTC_STATUSB, RTCSB_24HR); 167 writertc(RTC_STATUSA, rtc_statusa); 168 writertc(RTC_STATUSB, rtc_statusb); 169 rtcin(RTC_INTR); 170 } 171 172 /********************************************************************** 173 * RTC driver for subr_rtc 174 */ 175 176 struct atrtc_softc { 177 int port_rid, intr_rid; 178 struct resource *port_res; 179 struct resource *intr_res; 180 void *intr_handler; 181 struct eventtimer et; 182 }; 183 184 static int 185 rtc_start(struct eventtimer *et, sbintime_t first, sbintime_t period) 186 { 187 188 atrtc_rate(max(fls(period + (period >> 1)) - 17, 1)); 189 atrtc_enable_intr(); 190 return (0); 191 } 192 193 static int 194 rtc_stop(struct eventtimer *et) 195 { 196 197 atrtc_disable_intr(); 198 return (0); 199 } 200 201 /* 202 * This routine receives statistical clock interrupts from the RTC. 203 * As explained above, these occur at 128 interrupts per second. 204 * When profiling, we receive interrupts at a rate of 1024 Hz. 205 * 206 * This does not actually add as much overhead as it sounds, because 207 * when the statistical clock is active, the hardclock driver no longer 208 * needs to keep (inaccurate) statistics on its own. This decouples 209 * statistics gathering from scheduling interrupts. 210 * 211 * The RTC chip requires that we read status register C (RTC_INTR) 212 * to acknowledge an interrupt, before it will generate the next one. 213 * Under high interrupt load, rtcintr() can be indefinitely delayed and 214 * the clock can tick immediately after the read from RTC_INTR. In this 215 * case, the mc146818A interrupt signal will not drop for long enough 216 * to register with the 8259 PIC. If an interrupt is missed, the stat 217 * clock will halt, considerably degrading system performance. This is 218 * why we use 'while' rather than a more straightforward 'if' below. 219 * Stat clock ticks can still be lost, causing minor loss of accuracy 220 * in the statistics, but the stat clock will no longer stop. 221 */ 222 static int 223 rtc_intr(void *arg) 224 { 225 struct atrtc_softc *sc = (struct atrtc_softc *)arg; 226 int flag = 0; 227 228 while (rtcin(RTC_INTR) & RTCIR_PERIOD) { 229 flag = 1; 230 if (sc->et.et_active) 231 sc->et.et_event_cb(&sc->et, sc->et.et_arg); 232 } 233 return(flag ? FILTER_HANDLED : FILTER_STRAY); 234 } 235 236 /* 237 * Attach to the ISA PnP descriptors for the timer and realtime clock. 238 */ 239 static struct isa_pnp_id atrtc_ids[] = { 240 { 0x000bd041 /* PNP0B00 */, "AT realtime clock" }, 241 { 0 } 242 }; 243 244 static int 245 atrtc_probe(device_t dev) 246 { 247 int result; 248 249 result = ISA_PNP_PROBE(device_get_parent(dev), dev, atrtc_ids); 250 /* ENOENT means no PnP-ID, device is hinted. */ 251 if (result == ENOENT) { 252 device_set_desc(dev, "AT realtime clock"); 253 return (BUS_PROBE_LOW_PRIORITY); 254 } 255 return (result); 256 } 257 258 static int 259 atrtc_attach(device_t dev) 260 { 261 struct atrtc_softc *sc; 262 rman_res_t s; 263 int i; 264 265 sc = device_get_softc(dev); 266 sc->port_res = bus_alloc_resource(dev, SYS_RES_IOPORT, &sc->port_rid, 267 IO_RTC, IO_RTC + 1, 2, RF_ACTIVE); 268 if (sc->port_res == NULL) 269 device_printf(dev, "Warning: Couldn't map I/O.\n"); 270 atrtc_start(); 271 clock_register(dev, 1000000); 272 bzero(&sc->et, sizeof(struct eventtimer)); 273 if (!atrtcclock_disable && 274 (resource_int_value(device_get_name(dev), device_get_unit(dev), 275 "clock", &i) != 0 || i != 0)) { 276 sc->intr_rid = 0; 277 while (bus_get_resource(dev, SYS_RES_IRQ, sc->intr_rid, 278 &s, NULL) == 0 && s != 8) 279 sc->intr_rid++; 280 sc->intr_res = bus_alloc_resource(dev, SYS_RES_IRQ, 281 &sc->intr_rid, 8, 8, 1, RF_ACTIVE); 282 if (sc->intr_res == NULL) { 283 device_printf(dev, "Can't map interrupt.\n"); 284 return (0); 285 } else if ((bus_setup_intr(dev, sc->intr_res, INTR_TYPE_CLK, 286 rtc_intr, NULL, sc, &sc->intr_handler))) { 287 device_printf(dev, "Can't setup interrupt.\n"); 288 return (0); 289 } else { 290 /* Bind IRQ to BSP to avoid live migration. */ 291 bus_bind_intr(dev, sc->intr_res, 0); 292 } 293 sc->et.et_name = "RTC"; 294 sc->et.et_flags = ET_FLAGS_PERIODIC | ET_FLAGS_POW2DIV; 295 sc->et.et_quality = 0; 296 sc->et.et_frequency = 32768; 297 sc->et.et_min_period = 0x00080000; 298 sc->et.et_max_period = 0x80000000; 299 sc->et.et_start = rtc_start; 300 sc->et.et_stop = rtc_stop; 301 sc->et.et_priv = dev; 302 et_register(&sc->et); 303 } 304 return(0); 305 } 306 307 static int 308 atrtc_resume(device_t dev) 309 { 310 311 atrtc_restore(); 312 return(0); 313 } 314 315 static int 316 atrtc_settime(device_t dev __unused, struct timespec *ts) 317 { 318 struct bcd_clocktime bct; 319 320 clock_ts_to_bcd(ts, &bct, false); 321 322 mtx_lock(&atrtc_time_lock); 323 RTC_LOCK; 324 325 /* Disable RTC updates and interrupts. */ 326 rtcout_locked(RTC_STATUSB, RTCSB_HALT | RTCSB_24HR); 327 328 /* Write all the time registers. */ 329 rtcout_locked(RTC_SEC, bct.sec); 330 rtcout_locked(RTC_MIN, bct.min); 331 rtcout_locked(RTC_HRS, bct.hour); 332 rtcout_locked(RTC_WDAY, bct.dow + 1); 333 rtcout_locked(RTC_DAY, bct.day); 334 rtcout_locked(RTC_MONTH, bct.mon); 335 rtcout_locked(RTC_YEAR, bct.year & 0xff); 336 #ifdef USE_RTC_CENTURY 337 rtcout_locked(RTC_CENTURY, bct.year >> 8); 338 #endif 339 340 /* 341 * Re-enable RTC updates and interrupts. 342 */ 343 rtcout_locked(RTC_STATUSB, rtc_statusb); 344 rtcin_locked(RTC_INTR); 345 346 RTC_UNLOCK; 347 mtx_unlock(&atrtc_time_lock); 348 349 return (0); 350 } 351 352 static int 353 atrtc_gettime(device_t dev, struct timespec *ts) 354 { 355 struct bcd_clocktime bct; 356 357 /* Look if we have a RTC present and the time is valid */ 358 if (!(rtcin(RTC_STATUSD) & RTCSD_PWR)) { 359 device_printf(dev, "WARNING: Battery failure indication\n"); 360 return (EINVAL); 361 } 362 363 /* 364 * wait for time update to complete 365 * If RTCSA_TUP is zero, we have at least 244us before next update. 366 * This is fast enough on most hardware, but a refinement would be 367 * to make sure that no more than 240us pass after we start reading, 368 * and try again if so. 369 */ 370 mtx_lock(&atrtc_time_lock); 371 while (rtcin(RTC_STATUSA) & RTCSA_TUP) 372 continue; 373 RTC_LOCK; 374 bct.sec = rtcin_locked(RTC_SEC); 375 bct.min = rtcin_locked(RTC_MIN); 376 bct.hour = rtcin_locked(RTC_HRS); 377 bct.day = rtcin_locked(RTC_DAY); 378 bct.mon = rtcin_locked(RTC_MONTH); 379 bct.year = rtcin_locked(RTC_YEAR); 380 #ifdef USE_RTC_CENTURY 381 bct.year |= rtcin_locked(RTC_CENTURY) << 8; 382 #endif 383 RTC_UNLOCK; 384 mtx_unlock(&atrtc_time_lock); 385 /* dow is unused in timespec conversion and we have no nsec info. */ 386 bct.dow = 0; 387 bct.nsec = 0; 388 return (clock_bcd_to_ts(&bct, ts, false)); 389 } 390 391 static device_method_t atrtc_methods[] = { 392 /* Device interface */ 393 DEVMETHOD(device_probe, atrtc_probe), 394 DEVMETHOD(device_attach, atrtc_attach), 395 DEVMETHOD(device_detach, bus_generic_detach), 396 DEVMETHOD(device_shutdown, bus_generic_shutdown), 397 DEVMETHOD(device_suspend, bus_generic_suspend), 398 /* XXX stop statclock? */ 399 DEVMETHOD(device_resume, atrtc_resume), 400 401 /* clock interface */ 402 DEVMETHOD(clock_gettime, atrtc_gettime), 403 DEVMETHOD(clock_settime, atrtc_settime), 404 405 { 0, 0 } 406 }; 407 408 static driver_t atrtc_driver = { 409 "atrtc", 410 atrtc_methods, 411 sizeof(struct atrtc_softc), 412 }; 413 414 static devclass_t atrtc_devclass; 415 416 DRIVER_MODULE(atrtc, isa, atrtc_driver, atrtc_devclass, 0, 0); 417 DRIVER_MODULE(atrtc, acpi, atrtc_driver, atrtc_devclass, 0, 0); 418 ISA_PNP_INFO(atrtc_ids); 419 420 #include "opt_ddb.h" 421 #ifdef DDB 422 #include <ddb/ddb.h> 423 424 DB_SHOW_COMMAND(rtc, rtc) 425 { 426 printf("%02x/%02x/%02x %02x:%02x:%02x, A = %02x, B = %02x, C = %02x\n", 427 rtcin(RTC_YEAR), rtcin(RTC_MONTH), rtcin(RTC_DAY), 428 rtcin(RTC_HRS), rtcin(RTC_MIN), rtcin(RTC_SEC), 429 rtcin(RTC_STATUSA), rtcin(RTC_STATUSB), rtcin(RTC_INTR)); 430 } 431 #endif /* DDB */ 432