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 */ 20 static 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 */ 30 static 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 */ 69 static 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 10 * NSEC_PER_MSEC, /* EHCI_HRTIMER_DISABLE_PERIODIC */ 76 15 * NSEC_PER_MSEC, /* EHCI_HRTIMER_DISABLE_ASYNC */ 77 }; 78 79 /* Enable a pending hrtimer event */ 80 static void ehci_enable_event(struct ehci_hcd *ehci, unsigned event, 81 bool resched) 82 { 83 ktime_t *timeout = &ehci->hr_timeouts[event]; 84 85 if (resched) 86 *timeout = ktime_add(ktime_get(), 87 ktime_set(0, event_delays_ns[event])); 88 ehci->enabled_hrtimer_events |= (1 << event); 89 90 /* Track only the lowest-numbered pending event */ 91 if (event < ehci->next_hrtimer_event) { 92 ehci->next_hrtimer_event = event; 93 hrtimer_start_range_ns(&ehci->hrtimer, *timeout, 94 NSEC_PER_MSEC, HRTIMER_MODE_ABS); 95 } 96 } 97 98 99 /* Poll the STS_ASS status bit; see when it agrees with CMD_ASE */ 100 static void ehci_poll_ASS(struct ehci_hcd *ehci) 101 { 102 unsigned actual, want; 103 104 /* Don't enable anything if the controller isn't running (e.g., died) */ 105 if (ehci->rh_state != EHCI_RH_RUNNING) 106 return; 107 108 want = (ehci->command & CMD_ASE) ? STS_ASS : 0; 109 actual = ehci_readl(ehci, &ehci->regs->status) & STS_ASS; 110 111 if (want != actual) { 112 113 /* Poll again later, but give up after about 20 ms */ 114 if (ehci->ASS_poll_count++ < 20) { 115 ehci_enable_event(ehci, EHCI_HRTIMER_POLL_ASS, true); 116 return; 117 } 118 ehci_warn(ehci, "Waited too long for the async schedule status, giving up\n"); 119 } 120 ehci->ASS_poll_count = 0; 121 122 /* The status is up-to-date; restart or stop the schedule as needed */ 123 if (want == 0) { /* Stopped */ 124 if (ehci->async_count > 0) 125 ehci_set_command_bit(ehci, CMD_ASE); 126 127 } else { /* Running */ 128 if (ehci->async_count == 0) { 129 130 /* Turn off the schedule after a while */ 131 ehci_enable_event(ehci, EHCI_HRTIMER_DISABLE_ASYNC, 132 true); 133 } 134 } 135 } 136 137 /* Turn off the async schedule after a brief delay */ 138 static void ehci_disable_ASE(struct ehci_hcd *ehci) 139 { 140 ehci_clear_command_bit(ehci, CMD_ASE); 141 } 142 143 144 /* Poll the STS_PSS status bit; see when it agrees with CMD_PSE */ 145 static void ehci_poll_PSS(struct ehci_hcd *ehci) 146 { 147 unsigned actual, want; 148 149 /* Don't do anything if the controller isn't running (e.g., died) */ 150 if (ehci->rh_state != EHCI_RH_RUNNING) 151 return; 152 153 want = (ehci->command & CMD_PSE) ? STS_PSS : 0; 154 actual = ehci_readl(ehci, &ehci->regs->status) & STS_PSS; 155 156 if (want != actual) { 157 158 /* Poll again later, but give up after about 20 ms */ 159 if (ehci->PSS_poll_count++ < 20) { 160 ehci_enable_event(ehci, EHCI_HRTIMER_POLL_PSS, true); 161 return; 162 } 163 ehci_warn(ehci, "Waited too long for the periodic schedule status, giving up\n"); 164 } 165 ehci->PSS_poll_count = 0; 166 167 /* The status is up-to-date; restart or stop the schedule as needed */ 168 if (want == 0) { /* Stopped */ 169 if (ehci->periodic_count > 0) { 170 171 /* make sure ehci_work scans these */ 172 ehci->next_uframe = ehci_read_frame_index(ehci) 173 & ((ehci->periodic_size << 3) - 1); 174 ehci_set_command_bit(ehci, CMD_PSE); 175 } 176 177 } else { /* Running */ 178 if (ehci->periodic_count == 0) { 179 180 /* Turn off the schedule after a while */ 181 ehci_enable_event(ehci, EHCI_HRTIMER_DISABLE_PERIODIC, 182 true); 183 } 184 } 185 } 186 187 /* Turn off the periodic schedule after a brief delay */ 188 static void ehci_disable_PSE(struct ehci_hcd *ehci) 189 { 190 ehci_clear_command_bit(ehci, CMD_PSE); 191 } 192 193 194 /* Poll the STS_HALT status bit; see when a dead controller stops */ 195 static void ehci_handle_controller_death(struct ehci_hcd *ehci) 196 { 197 if (!(ehci_readl(ehci, &ehci->regs->status) & STS_HALT)) { 198 199 /* Give up after a few milliseconds */ 200 if (ehci->died_poll_count++ < 5) { 201 /* Try again later */ 202 ehci_enable_event(ehci, EHCI_HRTIMER_POLL_DEAD, true); 203 return; 204 } 205 ehci_warn(ehci, "Waited too long for the controller to stop, giving up\n"); 206 } 207 208 /* Clean up the mess */ 209 ehci->rh_state = EHCI_RH_HALTED; 210 ehci_writel(ehci, 0, &ehci->regs->configured_flag); 211 ehci_writel(ehci, 0, &ehci->regs->intr_enable); 212 ehci_work(ehci); 213 214 /* Not in process context, so don't try to reset the controller */ 215 } 216 217 218 /* Handle unlinked interrupt QHs once they are gone from the hardware */ 219 static void ehci_handle_intr_unlinks(struct ehci_hcd *ehci) 220 { 221 bool stopped = (ehci->rh_state < EHCI_RH_RUNNING); 222 223 /* 224 * Process all the QHs on the intr_unlink list that were added 225 * before the current unlink cycle began. The list is in 226 * temporal order, so stop when we reach the first entry in the 227 * current cycle. But if the root hub isn't running then 228 * process all the QHs on the list. 229 */ 230 ehci->intr_unlinking = true; 231 while (ehci->intr_unlink) { 232 struct ehci_qh *qh = ehci->intr_unlink; 233 234 if (!stopped && qh->unlink_cycle == ehci->intr_unlink_cycle) 235 break; 236 ehci->intr_unlink = qh->unlink_next; 237 qh->unlink_next = NULL; 238 end_unlink_intr(ehci, qh); 239 } 240 241 /* Handle remaining entries later */ 242 if (ehci->intr_unlink) { 243 ehci_enable_event(ehci, EHCI_HRTIMER_UNLINK_INTR, true); 244 ++ehci->intr_unlink_cycle; 245 } 246 ehci->intr_unlinking = false; 247 } 248 249 250 /* Start another free-iTDs/siTDs cycle */ 251 static void start_free_itds(struct ehci_hcd *ehci) 252 { 253 if (!(ehci->enabled_hrtimer_events & BIT(EHCI_HRTIMER_FREE_ITDS))) { 254 ehci->last_itd_to_free = list_entry( 255 ehci->cached_itd_list.prev, 256 struct ehci_itd, itd_list); 257 ehci->last_sitd_to_free = list_entry( 258 ehci->cached_sitd_list.prev, 259 struct ehci_sitd, sitd_list); 260 ehci_enable_event(ehci, EHCI_HRTIMER_FREE_ITDS, true); 261 } 262 } 263 264 /* Wait for controller to stop using old iTDs and siTDs */ 265 static void end_free_itds(struct ehci_hcd *ehci) 266 { 267 struct ehci_itd *itd, *n; 268 struct ehci_sitd *sitd, *sn; 269 270 if (ehci->rh_state < EHCI_RH_RUNNING) { 271 ehci->last_itd_to_free = NULL; 272 ehci->last_sitd_to_free = NULL; 273 } 274 275 list_for_each_entry_safe(itd, n, &ehci->cached_itd_list, itd_list) { 276 list_del(&itd->itd_list); 277 dma_pool_free(ehci->itd_pool, itd, itd->itd_dma); 278 if (itd == ehci->last_itd_to_free) 279 break; 280 } 281 list_for_each_entry_safe(sitd, sn, &ehci->cached_sitd_list, sitd_list) { 282 list_del(&sitd->sitd_list); 283 dma_pool_free(ehci->sitd_pool, sitd, sitd->sitd_dma); 284 if (sitd == ehci->last_sitd_to_free) 285 break; 286 } 287 288 if (!list_empty(&ehci->cached_itd_list) || 289 !list_empty(&ehci->cached_sitd_list)) 290 start_free_itds(ehci); 291 } 292 293 294 /* 295 * Handler functions for the hrtimer event types. 296 * Keep this array in the same order as the event types indexed by 297 * enum ehci_hrtimer_event in ehci.h. 298 */ 299 static void (*event_handlers[])(struct ehci_hcd *) = { 300 ehci_poll_ASS, /* EHCI_HRTIMER_POLL_ASS */ 301 ehci_poll_PSS, /* EHCI_HRTIMER_POLL_PSS */ 302 ehci_handle_controller_death, /* EHCI_HRTIMER_POLL_DEAD */ 303 ehci_handle_intr_unlinks, /* EHCI_HRTIMER_UNLINK_INTR */ 304 end_free_itds, /* EHCI_HRTIMER_FREE_ITDS */ 305 ehci_disable_PSE, /* EHCI_HRTIMER_DISABLE_PERIODIC */ 306 ehci_disable_ASE, /* EHCI_HRTIMER_DISABLE_ASYNC */ 307 }; 308 309 static enum hrtimer_restart ehci_hrtimer_func(struct hrtimer *t) 310 { 311 struct ehci_hcd *ehci = container_of(t, struct ehci_hcd, hrtimer); 312 ktime_t now; 313 unsigned long events; 314 unsigned long flags; 315 unsigned e; 316 317 spin_lock_irqsave(&ehci->lock, flags); 318 319 events = ehci->enabled_hrtimer_events; 320 ehci->enabled_hrtimer_events = 0; 321 ehci->next_hrtimer_event = EHCI_HRTIMER_NO_EVENT; 322 323 /* 324 * Check each pending event. If its time has expired, handle 325 * the event; otherwise re-enable it. 326 */ 327 now = ktime_get(); 328 for_each_set_bit(e, &events, EHCI_HRTIMER_NUM_EVENTS) { 329 if (now.tv64 >= ehci->hr_timeouts[e].tv64) 330 event_handlers[e](ehci); 331 else 332 ehci_enable_event(ehci, e, false); 333 } 334 335 spin_unlock_irqrestore(&ehci->lock, flags); 336 return HRTIMER_NORESTART; 337 } 338