1/* 2 * Copyright (C) 2012 by Alan Stern 3 * 4 * This program is free software; you can redistribute it and/or modify it 5 * under the terms of the GNU General Public License as published by the 6 * Free Software Foundation; either version 2 of the License, or (at your 7 * option) any later version. 8 * 9 * This program is distributed in the hope that it will be useful, but 10 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 11 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * for more details. 13 */ 14 15/* This file is part of ehci-hcd.c */ 16 17/*-------------------------------------------------------------------------*/ 18 19/* Set a bit in the USBCMD register */ 20static void ehci_set_command_bit(struct ehci_hcd *ehci, u32 bit) 21{ 22 ehci->command |= bit; 23 ehci_writel(ehci, ehci->command, &ehci->regs->command); 24 25 /* unblock posted write */ 26 ehci_readl(ehci, &ehci->regs->command); 27} 28 29/* Clear a bit in the USBCMD register */ 30static void ehci_clear_command_bit(struct ehci_hcd *ehci, u32 bit) 31{ 32 ehci->command &= ~bit; 33 ehci_writel(ehci, ehci->command, &ehci->regs->command); 34 35 /* unblock posted write */ 36 ehci_readl(ehci, &ehci->regs->command); 37} 38 39/*-------------------------------------------------------------------------*/ 40 41/* 42 * EHCI timer support... Now using hrtimers. 43 * 44 * Lots of different events are triggered from ehci->hrtimer. Whenever 45 * the timer routine runs, it checks each possible event; events that are 46 * currently enabled and whose expiration time has passed get handled. 47 * The set of enabled events is stored as a collection of bitflags in 48 * ehci->enabled_hrtimer_events, and they are numbered in order of 49 * increasing delay values (ranging between 1 ms and 100 ms). 50 * 51 * Rather than implementing a sorted list or tree of all pending events, 52 * we keep track only of the lowest-numbered pending event, in 53 * ehci->next_hrtimer_event. Whenever ehci->hrtimer gets restarted, its 54 * expiration time is set to the timeout value for this event. 55 * 56 * As a result, events might not get handled right away; the actual delay 57 * could be anywhere up to twice the requested delay. This doesn't 58 * matter, because none of the events are especially time-critical. The 59 * ones that matter most all have a delay of 1 ms, so they will be 60 * handled after 2 ms at most, which is okay. In addition to this, we 61 * allow for an expiration range of 1 ms. 62 */ 63 64/* 65 * Delay lengths for the hrtimer event types. 66 * Keep this list sorted by delay length, in the same order as 67 * the event types indexed by enum ehci_hrtimer_event in ehci.h. 68 */ 69static unsigned event_delays_ns[] = { 70 1 * NSEC_PER_MSEC, /* EHCI_HRTIMER_POLL_ASS */ 71 1 * NSEC_PER_MSEC, /* EHCI_HRTIMER_POLL_PSS */ 72 1 * NSEC_PER_MSEC, /* EHCI_HRTIMER_POLL_DEAD */ 73 1125 * NSEC_PER_USEC, /* EHCI_HRTIMER_UNLINK_INTR */ 74 2 * NSEC_PER_MSEC, /* EHCI_HRTIMER_FREE_ITDS */ 75 5 * NSEC_PER_MSEC, /* EHCI_HRTIMER_START_UNLINK_INTR */ 76 6 * NSEC_PER_MSEC, /* EHCI_HRTIMER_ASYNC_UNLINKS */ 77 10 * NSEC_PER_MSEC, /* EHCI_HRTIMER_IAA_WATCHDOG */ 78 10 * NSEC_PER_MSEC, /* EHCI_HRTIMER_DISABLE_PERIODIC */ 79 15 * NSEC_PER_MSEC, /* EHCI_HRTIMER_DISABLE_ASYNC */ 80 100 * NSEC_PER_MSEC, /* EHCI_HRTIMER_IO_WATCHDOG */ 81}; 82 83/* Enable a pending hrtimer event */ 84static void ehci_enable_event(struct ehci_hcd *ehci, unsigned event, 85 bool resched) 86{ 87 ktime_t *timeout = &ehci->hr_timeouts[event]; 88 89 if (resched) 90 *timeout = ktime_add(ktime_get(), 91 ktime_set(0, event_delays_ns[event])); 92 ehci->enabled_hrtimer_events |= (1 << event); 93 94 /* Track only the lowest-numbered pending event */ 95 if (event < ehci->next_hrtimer_event) { 96 ehci->next_hrtimer_event = event; 97 hrtimer_start_range_ns(&ehci->hrtimer, *timeout, 98 NSEC_PER_MSEC, HRTIMER_MODE_ABS); 99 } 100} 101 102 103/* Poll the STS_ASS status bit; see when it agrees with CMD_ASE */ 104static void ehci_poll_ASS(struct ehci_hcd *ehci) 105{ 106 unsigned actual, want; 107 108 /* Don't enable anything if the controller isn't running (e.g., died) */ 109 if (ehci->rh_state != EHCI_RH_RUNNING) 110 return; 111 112 want = (ehci->command & CMD_ASE) ? STS_ASS : 0; 113 actual = ehci_readl(ehci, &ehci->regs->status) & STS_ASS; 114 115 if (want != actual) { 116 117 /* Poll again later, but give up after about 2-4 ms */ 118 if (ehci->ASS_poll_count++ < 2) { 119 ehci_enable_event(ehci, EHCI_HRTIMER_POLL_ASS, true); 120 return; 121 } 122 ehci_dbg(ehci, "Waited too long for the async schedule status (%x/%x), giving up\n", 123 want, actual); 124 } 125 ehci->ASS_poll_count = 0; 126 127 /* The status is up-to-date; restart or stop the schedule as needed */ 128 if (want == 0) { /* Stopped */ 129 if (ehci->async_count > 0) 130 ehci_set_command_bit(ehci, CMD_ASE); 131 132 } else { /* Running */ 133 if (ehci->async_count == 0) { 134 135 /* Turn off the schedule after a while */ 136 ehci_enable_event(ehci, EHCI_HRTIMER_DISABLE_ASYNC, 137 true); 138 } 139 } 140} 141 142/* Turn off the async schedule after a brief delay */ 143static void ehci_disable_ASE(struct ehci_hcd *ehci) 144{ 145 ehci_clear_command_bit(ehci, CMD_ASE); 146} 147 148 149/* Poll the STS_PSS status bit; see when it agrees with CMD_PSE */ 150static void ehci_poll_PSS(struct ehci_hcd *ehci) 151{ 152 unsigned actual, want; 153 154 /* Don't do anything if the controller isn't running (e.g., died) */ 155 if (ehci->rh_state != EHCI_RH_RUNNING) 156 return; 157 158 want = (ehci->command & CMD_PSE) ? STS_PSS : 0; 159 actual = ehci_readl(ehci, &ehci->regs->status) & STS_PSS; 160 161 if (want != actual) { 162 163 /* Poll again later, but give up after about 2-4 ms */ 164 if (ehci->PSS_poll_count++ < 2) { 165 ehci_enable_event(ehci, EHCI_HRTIMER_POLL_PSS, true); 166 return; 167 } 168 ehci_dbg(ehci, "Waited too long for the periodic schedule status (%x/%x), giving up\n", 169 want, actual); 170 } 171 ehci->PSS_poll_count = 0; 172 173 /* The status is up-to-date; restart or stop the schedule as needed */ 174 if (want == 0) { /* Stopped */ 175 if (ehci->periodic_count > 0) 176 ehci_set_command_bit(ehci, CMD_PSE); 177 178 } else { /* Running */ 179 if (ehci->periodic_count == 0) { 180 181 /* Turn off the schedule after a while */ 182 ehci_enable_event(ehci, EHCI_HRTIMER_DISABLE_PERIODIC, 183 true); 184 } 185 } 186} 187 188/* Turn off the periodic schedule after a brief delay */ 189static void ehci_disable_PSE(struct ehci_hcd *ehci) 190{ 191 ehci_clear_command_bit(ehci, CMD_PSE); 192} 193 194 195/* Poll the STS_HALT status bit; see when a dead controller stops */ 196static void ehci_handle_controller_death(struct ehci_hcd *ehci) 197{ 198 if (!(ehci_readl(ehci, &ehci->regs->status) & STS_HALT)) { 199 200 /* Give up after a few milliseconds */ 201 if (ehci->died_poll_count++ < 5) { 202 /* Try again later */ 203 ehci_enable_event(ehci, EHCI_HRTIMER_POLL_DEAD, true); 204 return; 205 } 206 ehci_warn(ehci, "Waited too long for the controller to stop, giving up\n"); 207 } 208 209 /* Clean up the mess */ 210 ehci->rh_state = EHCI_RH_HALTED; 211 ehci_writel(ehci, 0, &ehci->regs->configured_flag); 212 ehci_writel(ehci, 0, &ehci->regs->intr_enable); 213 ehci_work(ehci); 214 end_unlink_async(ehci); 215 216 /* Not in process context, so don't try to reset the controller */ 217} 218 219/* start to unlink interrupt QHs */ 220static void ehci_handle_start_intr_unlinks(struct ehci_hcd *ehci) 221{ 222 bool stopped = (ehci->rh_state < EHCI_RH_RUNNING); 223 224 /* 225 * Process all the QHs on the intr_unlink list that were added 226 * before the current unlink cycle began. The list is in 227 * temporal order, so stop when we reach the first entry in the 228 * current cycle. But if the root hub isn't running then 229 * process all the QHs on the list. 230 */ 231 while (!list_empty(&ehci->intr_unlink_wait)) { 232 struct ehci_qh *qh; 233 234 qh = list_first_entry(&ehci->intr_unlink_wait, 235 struct ehci_qh, unlink_node); 236 if (!stopped && (qh->unlink_cycle == 237 ehci->intr_unlink_wait_cycle)) 238 break; 239 list_del_init(&qh->unlink_node); 240 start_unlink_intr(ehci, qh); 241 } 242 243 /* Handle remaining entries later */ 244 if (!list_empty(&ehci->intr_unlink_wait)) { 245 ehci_enable_event(ehci, EHCI_HRTIMER_START_UNLINK_INTR, true); 246 ++ehci->intr_unlink_wait_cycle; 247 } 248} 249 250/* Handle unlinked interrupt QHs once they are gone from the hardware */ 251static void ehci_handle_intr_unlinks(struct ehci_hcd *ehci) 252{ 253 bool stopped = (ehci->rh_state < EHCI_RH_RUNNING); 254 255 /* 256 * Process all the QHs on the intr_unlink list that were added 257 * before the current unlink cycle began. The list is in 258 * temporal order, so stop when we reach the first entry in the 259 * current cycle. But if the root hub isn't running then 260 * process all the QHs on the list. 261 */ 262 ehci->intr_unlinking = true; 263 while (!list_empty(&ehci->intr_unlink)) { 264 struct ehci_qh *qh; 265 266 qh = list_first_entry(&ehci->intr_unlink, struct ehci_qh, 267 unlink_node); 268 if (!stopped && qh->unlink_cycle == ehci->intr_unlink_cycle) 269 break; 270 list_del_init(&qh->unlink_node); 271 end_unlink_intr(ehci, qh); 272 } 273 274 /* Handle remaining entries later */ 275 if (!list_empty(&ehci->intr_unlink)) { 276 ehci_enable_event(ehci, EHCI_HRTIMER_UNLINK_INTR, true); 277 ++ehci->intr_unlink_cycle; 278 } 279 ehci->intr_unlinking = false; 280} 281 282 283/* Start another free-iTDs/siTDs cycle */ 284static void start_free_itds(struct ehci_hcd *ehci) 285{ 286 if (!(ehci->enabled_hrtimer_events & BIT(EHCI_HRTIMER_FREE_ITDS))) { 287 ehci->last_itd_to_free = list_entry( 288 ehci->cached_itd_list.prev, 289 struct ehci_itd, itd_list); 290 ehci->last_sitd_to_free = list_entry( 291 ehci->cached_sitd_list.prev, 292 struct ehci_sitd, sitd_list); 293 ehci_enable_event(ehci, EHCI_HRTIMER_FREE_ITDS, true); 294 } 295} 296 297/* Wait for controller to stop using old iTDs and siTDs */ 298static void end_free_itds(struct ehci_hcd *ehci) 299{ 300 struct ehci_itd *itd, *n; 301 struct ehci_sitd *sitd, *sn; 302 303 if (ehci->rh_state < EHCI_RH_RUNNING) { 304 ehci->last_itd_to_free = NULL; 305 ehci->last_sitd_to_free = NULL; 306 } 307 308 list_for_each_entry_safe(itd, n, &ehci->cached_itd_list, itd_list) { 309 list_del(&itd->itd_list); 310 dma_pool_free(ehci->itd_pool, itd, itd->itd_dma); 311 if (itd == ehci->last_itd_to_free) 312 break; 313 } 314 list_for_each_entry_safe(sitd, sn, &ehci->cached_sitd_list, sitd_list) { 315 list_del(&sitd->sitd_list); 316 dma_pool_free(ehci->sitd_pool, sitd, sitd->sitd_dma); 317 if (sitd == ehci->last_sitd_to_free) 318 break; 319 } 320 321 if (!list_empty(&ehci->cached_itd_list) || 322 !list_empty(&ehci->cached_sitd_list)) 323 start_free_itds(ehci); 324} 325 326 327/* Handle lost (or very late) IAA interrupts */ 328static void ehci_iaa_watchdog(struct ehci_hcd *ehci) 329{ 330 u32 cmd, status; 331 332 /* 333 * Lost IAA irqs wedge things badly; seen first with a vt8235. 334 * So we need this watchdog, but must protect it against both 335 * (a) SMP races against real IAA firing and retriggering, and 336 * (b) clean HC shutdown, when IAA watchdog was pending. 337 */ 338 if (!ehci->iaa_in_progress || ehci->rh_state != EHCI_RH_RUNNING) 339 return; 340 341 /* If we get here, IAA is *REALLY* late. It's barely 342 * conceivable that the system is so busy that CMD_IAAD 343 * is still legitimately set, so let's be sure it's 344 * clear before we read STS_IAA. (The HC should clear 345 * CMD_IAAD when it sets STS_IAA.) 346 */ 347 cmd = ehci_readl(ehci, &ehci->regs->command); 348 349 /* 350 * If IAA is set here it either legitimately triggered 351 * after the watchdog timer expired (_way_ late, so we'll 352 * still count it as lost) ... or a silicon erratum: 353 * - VIA seems to set IAA without triggering the IRQ; 354 * - IAAD potentially cleared without setting IAA. 355 */ 356 status = ehci_readl(ehci, &ehci->regs->status); 357 if ((status & STS_IAA) || !(cmd & CMD_IAAD)) { 358 COUNT(ehci->stats.lost_iaa); 359 ehci_writel(ehci, STS_IAA, &ehci->regs->status); 360 } 361 362 ehci_dbg(ehci, "IAA watchdog: status %x cmd %x\n", status, cmd); 363 end_unlink_async(ehci); 364} 365 366 367/* Enable the I/O watchdog, if appropriate */ 368static void turn_on_io_watchdog(struct ehci_hcd *ehci) 369{ 370 /* Not needed if the controller isn't running or it's already enabled */ 371 if (ehci->rh_state != EHCI_RH_RUNNING || 372 (ehci->enabled_hrtimer_events & 373 BIT(EHCI_HRTIMER_IO_WATCHDOG))) 374 return; 375 376 /* 377 * Isochronous transfers always need the watchdog. 378 * For other sorts we use it only if the flag is set. 379 */ 380 if (ehci->isoc_count > 0 || (ehci->need_io_watchdog && 381 ehci->async_count + ehci->intr_count > 0)) 382 ehci_enable_event(ehci, EHCI_HRTIMER_IO_WATCHDOG, true); 383} 384 385 386/* 387 * Handler functions for the hrtimer event types. 388 * Keep this array in the same order as the event types indexed by 389 * enum ehci_hrtimer_event in ehci.h. 390 */ 391static void (*event_handlers[])(struct ehci_hcd *) = { 392 ehci_poll_ASS, /* EHCI_HRTIMER_POLL_ASS */ 393 ehci_poll_PSS, /* EHCI_HRTIMER_POLL_PSS */ 394 ehci_handle_controller_death, /* EHCI_HRTIMER_POLL_DEAD */ 395 ehci_handle_intr_unlinks, /* EHCI_HRTIMER_UNLINK_INTR */ 396 end_free_itds, /* EHCI_HRTIMER_FREE_ITDS */ 397 ehci_handle_start_intr_unlinks, /* EHCI_HRTIMER_START_UNLINK_INTR */ 398 unlink_empty_async, /* EHCI_HRTIMER_ASYNC_UNLINKS */ 399 ehci_iaa_watchdog, /* EHCI_HRTIMER_IAA_WATCHDOG */ 400 ehci_disable_PSE, /* EHCI_HRTIMER_DISABLE_PERIODIC */ 401 ehci_disable_ASE, /* EHCI_HRTIMER_DISABLE_ASYNC */ 402 ehci_work, /* EHCI_HRTIMER_IO_WATCHDOG */ 403}; 404 405static enum hrtimer_restart ehci_hrtimer_func(struct hrtimer *t) 406{ 407 struct ehci_hcd *ehci = container_of(t, struct ehci_hcd, hrtimer); 408 ktime_t now; 409 unsigned long events; 410 unsigned long flags; 411 unsigned e; 412 413 spin_lock_irqsave(&ehci->lock, flags); 414 415 events = ehci->enabled_hrtimer_events; 416 ehci->enabled_hrtimer_events = 0; 417 ehci->next_hrtimer_event = EHCI_HRTIMER_NO_EVENT; 418 419 /* 420 * Check each pending event. If its time has expired, handle 421 * the event; otherwise re-enable it. 422 */ 423 now = ktime_get(); 424 for_each_set_bit(e, &events, EHCI_HRTIMER_NUM_EVENTS) { 425 if (now.tv64 >= ehci->hr_timeouts[e].tv64) 426 event_handlers[e](ehci); 427 else 428 ehci_enable_event(ehci, e, false); 429 } 430 431 spin_unlock_irqrestore(&ehci->lock, flags); 432 return HRTIMER_NORESTART; 433} 434