1 /*- 2 * Copyright (c) 2011 The FreeBSD Foundation 3 * All rights reserved. 4 * 5 * Developed by Ben Gray <ben.r.gray@gmail.com> 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. The name of the company nor the name of the author may be used to 16 * endorse or promote products derived from this software without specific 17 * prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 /** 33 * The ARM Cortex-A9 core can support a global timer plus a private and 34 * watchdog timer per core. This driver reserves memory and interrupt 35 * resources for accessing both timer register sets, these resources are 36 * stored globally and used to setup the timecount and eventtimer. 37 * 38 * The timecount timer uses the global 64-bit counter, whereas the 39 * per-CPU eventtimer uses the private 32-bit counters. 40 * 41 * 42 * REF: ARM Cortex-A9 MPCore, Technical Reference Manual (rev. r2p2) 43 */ 44 45 #include <sys/cdefs.h> 46 __FBSDID("$FreeBSD$"); 47 48 #include <sys/param.h> 49 #include <sys/systm.h> 50 #include <sys/bus.h> 51 #include <sys/kernel.h> 52 #include <sys/module.h> 53 #include <sys/malloc.h> 54 #include <sys/rman.h> 55 #include <sys/timeet.h> 56 #include <sys/timetc.h> 57 #include <sys/watchdog.h> 58 #include <machine/bus.h> 59 #include <machine/cpu.h> 60 #include <machine/intr.h> 61 62 #include <machine/machdep.h> /* For arm_set_delay */ 63 64 #include <dev/ofw/openfirm.h> 65 #include <dev/ofw/ofw_bus.h> 66 #include <dev/ofw/ofw_bus_subr.h> 67 68 #include <machine/bus.h> 69 70 #include <arm/arm/mpcore_timervar.h> 71 72 /* Private (per-CPU) timer register map */ 73 #define PRV_TIMER_LOAD 0x0000 74 #define PRV_TIMER_COUNT 0x0004 75 #define PRV_TIMER_CTRL 0x0008 76 #define PRV_TIMER_INTR 0x000C 77 78 #define PRV_TIMER_CTR_PRESCALER_SHIFT 8 79 #define PRV_TIMER_CTRL_IRQ_ENABLE (1UL << 2) 80 #define PRV_TIMER_CTRL_AUTO_RELOAD (1UL << 1) 81 #define PRV_TIMER_CTRL_TIMER_ENABLE (1UL << 0) 82 83 #define PRV_TIMER_INTR_EVENT (1UL << 0) 84 85 /* Global timer register map */ 86 #define GBL_TIMER_COUNT_LOW 0x0000 87 #define GBL_TIMER_COUNT_HIGH 0x0004 88 #define GBL_TIMER_CTRL 0x0008 89 #define GBL_TIMER_INTR 0x000C 90 91 #define GBL_TIMER_CTR_PRESCALER_SHIFT 8 92 #define GBL_TIMER_CTRL_AUTO_INC (1UL << 3) 93 #define GBL_TIMER_CTRL_IRQ_ENABLE (1UL << 2) 94 #define GBL_TIMER_CTRL_COMP_ENABLE (1UL << 1) 95 #define GBL_TIMER_CTRL_TIMER_ENABLE (1UL << 0) 96 97 #define GBL_TIMER_INTR_EVENT (1UL << 0) 98 99 struct arm_tmr_softc { 100 device_t dev; 101 int irqrid; 102 int memrid; 103 struct resource * gbl_mem; 104 struct resource * prv_mem; 105 struct resource * prv_irq; 106 uint64_t clkfreq; 107 struct eventtimer et; 108 }; 109 110 static struct eventtimer *arm_tmr_et; 111 static struct timecounter *arm_tmr_tc; 112 static uint64_t arm_tmr_freq; 113 static boolean_t arm_tmr_freq_varies; 114 115 #define tmr_prv_read_4(sc, reg) bus_read_4((sc)->prv_mem, reg) 116 #define tmr_prv_write_4(sc, reg, val) bus_write_4((sc)->prv_mem, reg, val) 117 #define tmr_gbl_read_4(sc, reg) bus_read_4((sc)->gbl_mem, reg) 118 #define tmr_gbl_write_4(sc, reg, val) bus_write_4((sc)->gbl_mem, reg, val) 119 120 static void arm_tmr_delay(int, void *); 121 122 static timecounter_get_t arm_tmr_get_timecount; 123 124 static struct timecounter arm_tmr_timecount = { 125 .tc_name = "MPCore", 126 .tc_get_timecount = arm_tmr_get_timecount, 127 .tc_poll_pps = NULL, 128 .tc_counter_mask = ~0u, 129 .tc_frequency = 0, 130 .tc_quality = 800, 131 }; 132 133 #define TMR_GBL 0x01 134 #define TMR_PRV 0x02 135 #define TMR_BOTH (TMR_GBL | TMR_PRV) 136 #define TMR_NONE 0 137 138 static struct ofw_compat_data compat_data[] = { 139 {"arm,mpcore-timers", TMR_BOTH}, /* Non-standard, FreeBSD. */ 140 {"arm,cortex-a9-global-timer", TMR_GBL}, 141 {"arm,cortex-a5-global-timer", TMR_GBL}, 142 {"arm,cortex-a9-twd-timer", TMR_PRV}, 143 {"arm,cortex-a5-twd-timer", TMR_PRV}, 144 {"arm,arm11mp-twd-timer", TMR_PRV}, 145 {NULL, TMR_NONE} 146 }; 147 148 /** 149 * arm_tmr_get_timecount - reads the timecount (global) timer 150 * @tc: pointer to arm_tmr_timecount struct 151 * 152 * We only read the lower 32-bits, the timecount stuff only uses 32-bits 153 * so (for now?) ignore the upper 32-bits. 154 * 155 * RETURNS 156 * The lower 32-bits of the counter. 157 */ 158 static unsigned 159 arm_tmr_get_timecount(struct timecounter *tc) 160 { 161 struct arm_tmr_softc *sc; 162 163 sc = tc->tc_priv; 164 return (tmr_gbl_read_4(sc, GBL_TIMER_COUNT_LOW)); 165 } 166 167 /** 168 * arm_tmr_start - starts the eventtimer (private) timer 169 * @et: pointer to eventtimer struct 170 * @first: the number of seconds and fractional sections to trigger in 171 * @period: the period (in seconds and fractional sections) to set 172 * 173 * If the eventtimer is required to be in oneshot mode, period will be 174 * NULL and first will point to the time to trigger. If in periodic mode 175 * period will contain the time period and first may optionally contain 176 * the time for the first period. 177 * 178 * RETURNS 179 * Always returns 0 180 */ 181 static int 182 arm_tmr_start(struct eventtimer *et, sbintime_t first, sbintime_t period) 183 { 184 struct arm_tmr_softc *sc; 185 uint32_t load, count; 186 uint32_t ctrl; 187 188 sc = et->et_priv; 189 tmr_prv_write_4(sc, PRV_TIMER_CTRL, 0); 190 tmr_prv_write_4(sc, PRV_TIMER_INTR, PRV_TIMER_INTR_EVENT); 191 192 ctrl = PRV_TIMER_CTRL_IRQ_ENABLE | PRV_TIMER_CTRL_TIMER_ENABLE; 193 194 if (period != 0) { 195 load = ((uint32_t)et->et_frequency * period) >> 32; 196 ctrl |= PRV_TIMER_CTRL_AUTO_RELOAD; 197 } else 198 load = 0; 199 200 if (first != 0) 201 count = (uint32_t)((et->et_frequency * first) >> 32); 202 else 203 count = load; 204 205 tmr_prv_write_4(sc, PRV_TIMER_LOAD, load); 206 tmr_prv_write_4(sc, PRV_TIMER_COUNT, count); 207 tmr_prv_write_4(sc, PRV_TIMER_CTRL, ctrl); 208 209 return (0); 210 } 211 212 /** 213 * arm_tmr_stop - stops the eventtimer (private) timer 214 * @et: pointer to eventtimer struct 215 * 216 * Simply stops the private timer by clearing all bits in the ctrl register. 217 * 218 * RETURNS 219 * Always returns 0 220 */ 221 static int 222 arm_tmr_stop(struct eventtimer *et) 223 { 224 struct arm_tmr_softc *sc; 225 226 sc = et->et_priv; 227 tmr_prv_write_4(sc, PRV_TIMER_CTRL, 0); 228 tmr_prv_write_4(sc, PRV_TIMER_INTR, PRV_TIMER_INTR_EVENT); 229 return (0); 230 } 231 232 /** 233 * arm_tmr_intr - ISR for the eventtimer (private) timer 234 * @arg: pointer to arm_tmr_softc struct 235 * 236 * Clears the event register and then calls the eventtimer callback. 237 * 238 * RETURNS 239 * Always returns FILTER_HANDLED 240 */ 241 static int 242 arm_tmr_intr(void *arg) 243 { 244 struct arm_tmr_softc *sc; 245 246 sc = arg; 247 tmr_prv_write_4(sc, PRV_TIMER_INTR, PRV_TIMER_INTR_EVENT); 248 if (sc->et.et_active) 249 sc->et.et_event_cb(&sc->et, sc->et.et_arg); 250 return (FILTER_HANDLED); 251 } 252 253 254 255 256 /** 257 * arm_tmr_probe - timer probe routine 258 * @dev: new device 259 * 260 * The probe function returns success when probed with the fdt compatible 261 * string set to "arm,mpcore-timers". 262 * 263 * RETURNS 264 * BUS_PROBE_DEFAULT if the fdt device is compatible, otherwise ENXIO. 265 */ 266 static int 267 arm_tmr_probe(device_t dev) 268 { 269 270 if (!ofw_bus_status_okay(dev)) 271 return (ENXIO); 272 273 if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == TMR_NONE) 274 return (ENXIO); 275 276 device_set_desc(dev, "ARM MPCore Timers"); 277 return (BUS_PROBE_DEFAULT); 278 } 279 280 static int 281 attach_tc(struct arm_tmr_softc *sc) 282 { 283 int rid; 284 285 if (arm_tmr_tc != NULL) 286 return (EBUSY); 287 288 rid = sc->memrid; 289 sc->gbl_mem = bus_alloc_resource_any(sc->dev, SYS_RES_MEMORY, &rid, 290 RF_ACTIVE); 291 if (sc->gbl_mem == NULL) { 292 device_printf(sc->dev, "could not allocate gbl mem resources\n"); 293 return (ENXIO); 294 } 295 tmr_gbl_write_4(sc, GBL_TIMER_CTRL, 0x00000000); 296 297 arm_tmr_timecount.tc_frequency = sc->clkfreq; 298 arm_tmr_timecount.tc_priv = sc; 299 tc_init(&arm_tmr_timecount); 300 arm_tmr_tc = &arm_tmr_timecount; 301 302 tmr_gbl_write_4(sc, GBL_TIMER_CTRL, GBL_TIMER_CTRL_TIMER_ENABLE); 303 304 return (0); 305 } 306 307 static int 308 attach_et(struct arm_tmr_softc *sc) 309 { 310 void *ihl; 311 int irid, mrid; 312 313 if (arm_tmr_et != NULL) 314 return (EBUSY); 315 316 mrid = sc->memrid; 317 sc->prv_mem = bus_alloc_resource_any(sc->dev, SYS_RES_MEMORY, &mrid, 318 RF_ACTIVE); 319 if (sc->prv_mem == NULL) { 320 device_printf(sc->dev, "could not allocate prv mem resources\n"); 321 return (ENXIO); 322 } 323 tmr_prv_write_4(sc, PRV_TIMER_CTRL, 0x00000000); 324 325 irid = sc->irqrid; 326 sc->prv_irq = bus_alloc_resource_any(sc->dev, SYS_RES_IRQ, &irid, RF_ACTIVE); 327 if (sc->prv_irq == NULL) { 328 bus_release_resource(sc->dev, SYS_RES_MEMORY, mrid, sc->prv_mem); 329 device_printf(sc->dev, "could not allocate prv irq resources\n"); 330 return (ENXIO); 331 } 332 333 if (bus_setup_intr(sc->dev, sc->prv_irq, INTR_TYPE_CLK, arm_tmr_intr, 334 NULL, sc, &ihl) != 0) { 335 bus_release_resource(sc->dev, SYS_RES_MEMORY, mrid, sc->prv_mem); 336 bus_release_resource(sc->dev, SYS_RES_IRQ, irid, sc->prv_irq); 337 device_printf(sc->dev, "unable to setup the et irq handler.\n"); 338 return (ENXIO); 339 } 340 341 /* 342 * Setup and register the eventtimer. Most event timers set their min 343 * and max period values to some value calculated from the clock 344 * frequency. We might not know yet what our runtime clock frequency 345 * will be, so we just use some safe values. A max of 2 seconds ensures 346 * that even if our base clock frequency is 2GHz (meaning a 4GHz CPU), 347 * we won't overflow our 32-bit timer count register. A min of 20 348 * nanoseconds is pretty much completely arbitrary. 349 */ 350 sc->et.et_name = "MPCore"; 351 sc->et.et_flags = ET_FLAGS_PERIODIC | ET_FLAGS_ONESHOT | ET_FLAGS_PERCPU; 352 sc->et.et_quality = 1000; 353 sc->et.et_frequency = sc->clkfreq; 354 sc->et.et_min_period = nstosbt(20); 355 sc->et.et_max_period = 2 * SBT_1S; 356 sc->et.et_start = arm_tmr_start; 357 sc->et.et_stop = arm_tmr_stop; 358 sc->et.et_priv = sc; 359 et_register(&sc->et); 360 arm_tmr_et = &sc->et; 361 362 return (0); 363 } 364 365 /** 366 * arm_tmr_attach - attaches the timer to the simplebus 367 * @dev: new device 368 * 369 * Reserves memory and interrupt resources, stores the softc structure 370 * globally and registers both the timecount and eventtimer objects. 371 * 372 * RETURNS 373 * Zero on success or ENXIO if an error occuried. 374 */ 375 static int 376 arm_tmr_attach(device_t dev) 377 { 378 struct arm_tmr_softc *sc; 379 phandle_t node; 380 pcell_t clock; 381 int et_err, tc_err, tmrtype; 382 383 sc = device_get_softc(dev); 384 sc->dev = dev; 385 386 if (arm_tmr_freq_varies) { 387 sc->clkfreq = arm_tmr_freq; 388 } else { 389 if (arm_tmr_freq != 0) { 390 sc->clkfreq = arm_tmr_freq; 391 } else { 392 /* Get the base clock frequency */ 393 node = ofw_bus_get_node(dev); 394 if ((OF_getencprop(node, "clock-frequency", &clock, 395 sizeof(clock))) <= 0) { 396 device_printf(dev, "missing clock-frequency " 397 "attribute in FDT\n"); 398 return (ENXIO); 399 } 400 sc->clkfreq = clock; 401 } 402 } 403 404 tmrtype = ofw_bus_search_compatible(dev, compat_data)->ocd_data; 405 tc_err = ENXIO; 406 et_err = ENXIO; 407 408 /* 409 * If we're handling the global timer and it is fixed-frequency, set it 410 * up to use as a timecounter. If it's variable frequency it won't work 411 * as a timecounter. We also can't use it for DELAY(), so hopefully the 412 * platform provides its own implementation. If it doesn't, ours will 413 * get used, but since the frequency isn't set, it will only use the 414 * bogus loop counter. 415 */ 416 if (tmrtype & TMR_GBL) { 417 if (!arm_tmr_freq_varies) 418 tc_err = attach_tc(sc); 419 else if (bootverbose) 420 device_printf(sc->dev, 421 "not using variable-frequency device as timecounter"); 422 sc->memrid++; 423 sc->irqrid++; 424 } 425 426 /* If we are handling the private timer, set it up as an eventtimer. */ 427 if (tmrtype & TMR_PRV) { 428 et_err = attach_et(sc); 429 } 430 431 /* 432 * If we didn't successfully set up a timecounter or eventtimer then we 433 * didn't actually attach at all, return error. 434 */ 435 if (tc_err != 0 && et_err != 0) { 436 return (ENXIO); 437 } 438 439 #ifdef PLATFORM 440 /* 441 * We can register as the DELAY() implementation only if we successfully 442 * set up the global timer. 443 */ 444 if (tc_err == 0) 445 arm_set_delay(arm_tmr_delay, sc); 446 #endif 447 448 return (0); 449 } 450 451 static device_method_t arm_tmr_methods[] = { 452 DEVMETHOD(device_probe, arm_tmr_probe), 453 DEVMETHOD(device_attach, arm_tmr_attach), 454 { 0, 0 } 455 }; 456 457 static driver_t arm_tmr_driver = { 458 "mp_tmr", 459 arm_tmr_methods, 460 sizeof(struct arm_tmr_softc), 461 }; 462 463 static devclass_t arm_tmr_devclass; 464 465 EARLY_DRIVER_MODULE(mp_tmr, simplebus, arm_tmr_driver, arm_tmr_devclass, 0, 0, 466 BUS_PASS_TIMER + BUS_PASS_ORDER_MIDDLE); 467 EARLY_DRIVER_MODULE(mp_tmr, ofwbus, arm_tmr_driver, arm_tmr_devclass, 0, 0, 468 BUS_PASS_TIMER + BUS_PASS_ORDER_MIDDLE); 469 470 /* 471 * Handle a change in clock frequency. The mpcore timer runs at half the CPU 472 * frequency. When the CPU frequency changes due to power-saving or thermal 473 * management, the platform-specific code that causes the frequency change calls 474 * this routine to inform the clock driver, and we in turn inform the event 475 * timer system, which actually updates the value in et->frequency for us and 476 * reschedules the current event(s) in a way that's atomic with respect to 477 * start/stop/intr code that may be running on various CPUs at the time of the 478 * call. 479 * 480 * This routine can also be called by a platform's early init code. If the 481 * value passed is ARM_TMR_FREQUENCY_VARIES, that will cause the attach() code 482 * to register as an eventtimer, but not a timecounter. If the value passed in 483 * is any other non-zero value it is used as the fixed frequency for the timer. 484 */ 485 void 486 arm_tmr_change_frequency(uint64_t newfreq) 487 { 488 489 if (newfreq == ARM_TMR_FREQUENCY_VARIES) { 490 arm_tmr_freq_varies = true; 491 return; 492 } 493 494 arm_tmr_freq = newfreq; 495 if (arm_tmr_et != NULL) 496 et_change_frequency(arm_tmr_et, newfreq); 497 } 498 499 static void 500 arm_tmr_delay(int usec, void *arg) 501 { 502 struct arm_tmr_softc *sc = arg; 503 int32_t counts_per_usec; 504 int32_t counts; 505 uint32_t first, last; 506 507 /* Get the number of times to count */ 508 counts_per_usec = ((arm_tmr_timecount.tc_frequency / 1000000) + 1); 509 510 /* 511 * Clamp the timeout at a maximum value (about 32 seconds with 512 * a 66MHz clock). *Nobody* should be delay()ing for anywhere 513 * near that length of time and if they are, they should be hung 514 * out to dry. 515 */ 516 if (usec >= (0x80000000U / counts_per_usec)) 517 counts = (0x80000000U / counts_per_usec) - 1; 518 else 519 counts = usec * counts_per_usec; 520 521 first = tmr_gbl_read_4(sc, GBL_TIMER_COUNT_LOW); 522 523 while (counts > 0) { 524 last = tmr_gbl_read_4(sc, GBL_TIMER_COUNT_LOW); 525 counts -= (int32_t)(last - first); 526 first = last; 527 } 528 } 529 530 #ifndef PLATFORM 531 /** 532 * DELAY - Delay for at least usec microseconds. 533 * @usec: number of microseconds to delay by 534 * 535 * This function is called all over the kernel and is suppose to provide a 536 * consistent delay. This function may also be called before the console 537 * is setup so no printf's can be called here. 538 * 539 * RETURNS: 540 * nothing 541 */ 542 void 543 DELAY(int usec) 544 { 545 struct arm_tmr_softc *sc; 546 int32_t counts; 547 548 /* Check the timers are setup, if not just use a for loop for the meantime */ 549 if (arm_tmr_tc == NULL || arm_tmr_timecount.tc_frequency == 0) { 550 for (; usec > 0; usec--) 551 for (counts = 200; counts > 0; counts--) 552 cpufunc_nullop(); /* Prevent gcc from optimizing 553 * out the loop 554 */ 555 } else { 556 sc = arm_tmr_tc->tc_priv; 557 arm_tmr_delay(usec, sc); 558 } 559 } 560 #endif 561