1 /* 2 * linux/drivers/mmc/core/sdio_irq.c 3 * 4 * Author: Nicolas Pitre 5 * Created: June 18, 2007 6 * Copyright: MontaVista Software Inc. 7 * 8 * Copyright 2008 Pierre Ossman 9 * 10 * This program is free software; you can redistribute it and/or modify 11 * it under the terms of the GNU General Public License as published by 12 * the Free Software Foundation; either version 2 of the License, or (at 13 * your option) any later version. 14 */ 15 16 #include <linux/kernel.h> 17 #include <linux/sched.h> 18 #include <linux/kthread.h> 19 #include <linux/export.h> 20 #include <linux/wait.h> 21 #include <linux/delay.h> 22 23 #include <linux/mmc/core.h> 24 #include <linux/mmc/host.h> 25 #include <linux/mmc/card.h> 26 #include <linux/mmc/sdio.h> 27 #include <linux/mmc/sdio_func.h> 28 29 #include "sdio_ops.h" 30 #include "core.h" 31 #include "card.h" 32 33 static int process_sdio_pending_irqs(struct mmc_host *host) 34 { 35 struct mmc_card *card = host->card; 36 int i, ret, count; 37 unsigned char pending; 38 struct sdio_func *func; 39 40 /* 41 * Optimization, if there is only 1 function interrupt registered 42 * and we know an IRQ was signaled then call irq handler directly. 43 * Otherwise do the full probe. 44 */ 45 func = card->sdio_single_irq; 46 if (func && host->sdio_irq_pending) { 47 func->irq_handler(func); 48 return 1; 49 } 50 51 ret = mmc_io_rw_direct(card, 0, 0, SDIO_CCCR_INTx, 0, &pending); 52 if (ret) { 53 pr_debug("%s: error %d reading SDIO_CCCR_INTx\n", 54 mmc_card_id(card), ret); 55 return ret; 56 } 57 58 if (pending && mmc_card_broken_irq_polling(card) && 59 !(host->caps & MMC_CAP_SDIO_IRQ)) { 60 unsigned char dummy; 61 62 /* A fake interrupt could be created when we poll SDIO_CCCR_INTx 63 * register with a Marvell SD8797 card. A dummy CMD52 read to 64 * function 0 register 0xff can avoid this. 65 */ 66 mmc_io_rw_direct(card, 0, 0, 0xff, 0, &dummy); 67 } 68 69 count = 0; 70 for (i = 1; i <= 7; i++) { 71 if (pending & (1 << i)) { 72 func = card->sdio_func[i - 1]; 73 if (!func) { 74 pr_warn("%s: pending IRQ for non-existent function\n", 75 mmc_card_id(card)); 76 ret = -EINVAL; 77 } else if (func->irq_handler) { 78 func->irq_handler(func); 79 count++; 80 } else { 81 pr_warn("%s: pending IRQ with no handler\n", 82 sdio_func_id(func)); 83 ret = -EINVAL; 84 } 85 } 86 } 87 88 if (count) 89 return count; 90 91 return ret; 92 } 93 94 void sdio_run_irqs(struct mmc_host *host) 95 { 96 mmc_claim_host(host); 97 host->sdio_irq_pending = true; 98 process_sdio_pending_irqs(host); 99 mmc_release_host(host); 100 } 101 EXPORT_SYMBOL_GPL(sdio_run_irqs); 102 103 static int sdio_irq_thread(void *_host) 104 { 105 struct mmc_host *host = _host; 106 struct sched_param param = { .sched_priority = 1 }; 107 unsigned long period, idle_period; 108 int ret; 109 110 sched_setscheduler(current, SCHED_FIFO, ¶m); 111 112 /* 113 * We want to allow for SDIO cards to work even on non SDIO 114 * aware hosts. One thing that non SDIO host cannot do is 115 * asynchronous notification of pending SDIO card interrupts 116 * hence we poll for them in that case. 117 */ 118 idle_period = msecs_to_jiffies(10); 119 period = (host->caps & MMC_CAP_SDIO_IRQ) ? 120 MAX_SCHEDULE_TIMEOUT : idle_period; 121 122 pr_debug("%s: IRQ thread started (poll period = %lu jiffies)\n", 123 mmc_hostname(host), period); 124 125 do { 126 /* 127 * We claim the host here on drivers behalf for a couple 128 * reasons: 129 * 130 * 1) it is already needed to retrieve the CCCR_INTx; 131 * 2) we want the driver(s) to clear the IRQ condition ASAP; 132 * 3) we need to control the abort condition locally. 133 * 134 * Just like traditional hard IRQ handlers, we expect SDIO 135 * IRQ handlers to be quick and to the point, so that the 136 * holding of the host lock does not cover too much work 137 * that doesn't require that lock to be held. 138 */ 139 ret = __mmc_claim_host(host, &host->sdio_irq_thread_abort); 140 if (ret) 141 break; 142 ret = process_sdio_pending_irqs(host); 143 host->sdio_irq_pending = false; 144 mmc_release_host(host); 145 146 /* 147 * Give other threads a chance to run in the presence of 148 * errors. 149 */ 150 if (ret < 0) { 151 set_current_state(TASK_INTERRUPTIBLE); 152 if (!kthread_should_stop()) 153 schedule_timeout(HZ); 154 set_current_state(TASK_RUNNING); 155 } 156 157 /* 158 * Adaptive polling frequency based on the assumption 159 * that an interrupt will be closely followed by more. 160 * This has a substantial benefit for network devices. 161 */ 162 if (!(host->caps & MMC_CAP_SDIO_IRQ)) { 163 if (ret > 0) 164 period /= 2; 165 else { 166 period++; 167 if (period > idle_period) 168 period = idle_period; 169 } 170 } 171 172 set_current_state(TASK_INTERRUPTIBLE); 173 if (host->caps & MMC_CAP_SDIO_IRQ) 174 host->ops->enable_sdio_irq(host, 1); 175 if (!kthread_should_stop()) 176 schedule_timeout(period); 177 set_current_state(TASK_RUNNING); 178 } while (!kthread_should_stop()); 179 180 if (host->caps & MMC_CAP_SDIO_IRQ) 181 host->ops->enable_sdio_irq(host, 0); 182 183 pr_debug("%s: IRQ thread exiting with code %d\n", 184 mmc_hostname(host), ret); 185 186 return ret; 187 } 188 189 static int sdio_card_irq_get(struct mmc_card *card) 190 { 191 struct mmc_host *host = card->host; 192 193 WARN_ON(!host->claimed); 194 195 if (!host->sdio_irqs++) { 196 if (!(host->caps2 & MMC_CAP2_SDIO_IRQ_NOTHREAD)) { 197 atomic_set(&host->sdio_irq_thread_abort, 0); 198 host->sdio_irq_thread = 199 kthread_run(sdio_irq_thread, host, 200 "ksdioirqd/%s", mmc_hostname(host)); 201 if (IS_ERR(host->sdio_irq_thread)) { 202 int err = PTR_ERR(host->sdio_irq_thread); 203 host->sdio_irqs--; 204 return err; 205 } 206 } else if (host->caps & MMC_CAP_SDIO_IRQ) { 207 host->ops->enable_sdio_irq(host, 1); 208 } 209 } 210 211 return 0; 212 } 213 214 static int sdio_card_irq_put(struct mmc_card *card) 215 { 216 struct mmc_host *host = card->host; 217 218 WARN_ON(!host->claimed); 219 220 if (host->sdio_irqs < 1) 221 return -EINVAL; 222 223 if (!--host->sdio_irqs) { 224 if (!(host->caps2 & MMC_CAP2_SDIO_IRQ_NOTHREAD)) { 225 atomic_set(&host->sdio_irq_thread_abort, 1); 226 kthread_stop(host->sdio_irq_thread); 227 } else if (host->caps & MMC_CAP_SDIO_IRQ) { 228 host->ops->enable_sdio_irq(host, 0); 229 } 230 } 231 232 return 0; 233 } 234 235 /* If there is only 1 function registered set sdio_single_irq */ 236 static void sdio_single_irq_set(struct mmc_card *card) 237 { 238 struct sdio_func *func; 239 int i; 240 241 card->sdio_single_irq = NULL; 242 if ((card->host->caps & MMC_CAP_SDIO_IRQ) && 243 card->host->sdio_irqs == 1) 244 for (i = 0; i < card->sdio_funcs; i++) { 245 func = card->sdio_func[i]; 246 if (func && func->irq_handler) { 247 card->sdio_single_irq = func; 248 break; 249 } 250 } 251 } 252 253 /** 254 * sdio_claim_irq - claim the IRQ for a SDIO function 255 * @func: SDIO function 256 * @handler: IRQ handler callback 257 * 258 * Claim and activate the IRQ for the given SDIO function. The provided 259 * handler will be called when that IRQ is asserted. The host is always 260 * claimed already when the handler is called so the handler must not 261 * call sdio_claim_host() nor sdio_release_host(). 262 */ 263 int sdio_claim_irq(struct sdio_func *func, sdio_irq_handler_t *handler) 264 { 265 int ret; 266 unsigned char reg; 267 268 if (!func) 269 return -EINVAL; 270 271 pr_debug("SDIO: Enabling IRQ for %s...\n", sdio_func_id(func)); 272 273 if (func->irq_handler) { 274 pr_debug("SDIO: IRQ for %s already in use.\n", sdio_func_id(func)); 275 return -EBUSY; 276 } 277 278 ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, ®); 279 if (ret) 280 return ret; 281 282 reg |= 1 << func->num; 283 284 reg |= 1; /* Master interrupt enable */ 285 286 ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL); 287 if (ret) 288 return ret; 289 290 func->irq_handler = handler; 291 ret = sdio_card_irq_get(func->card); 292 if (ret) 293 func->irq_handler = NULL; 294 sdio_single_irq_set(func->card); 295 296 return ret; 297 } 298 EXPORT_SYMBOL_GPL(sdio_claim_irq); 299 300 /** 301 * sdio_release_irq - release the IRQ for a SDIO function 302 * @func: SDIO function 303 * 304 * Disable and release the IRQ for the given SDIO function. 305 */ 306 int sdio_release_irq(struct sdio_func *func) 307 { 308 int ret; 309 unsigned char reg; 310 311 if (!func) 312 return -EINVAL; 313 314 pr_debug("SDIO: Disabling IRQ for %s...\n", sdio_func_id(func)); 315 316 if (func->irq_handler) { 317 func->irq_handler = NULL; 318 sdio_card_irq_put(func->card); 319 sdio_single_irq_set(func->card); 320 } 321 322 ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, ®); 323 if (ret) 324 return ret; 325 326 reg &= ~(1 << func->num); 327 328 /* Disable master interrupt with the last function interrupt */ 329 if (!(reg & 0xFE)) 330 reg = 0; 331 332 ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL); 333 if (ret) 334 return ret; 335 336 return 0; 337 } 338 EXPORT_SYMBOL_GPL(sdio_release_irq); 339 340