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 31 static int process_sdio_pending_irqs(struct mmc_host *host) 32 { 33 struct mmc_card *card = host->card; 34 int i, ret, count; 35 unsigned char pending; 36 struct sdio_func *func; 37 38 /* 39 * Optimization, if there is only 1 function interrupt registered 40 * and we know an IRQ was signaled then call irq handler directly. 41 * Otherwise do the full probe. 42 */ 43 func = card->sdio_single_irq; 44 if (func && host->sdio_irq_pending) { 45 func->irq_handler(func); 46 return 1; 47 } 48 49 ret = mmc_io_rw_direct(card, 0, 0, SDIO_CCCR_INTx, 0, &pending); 50 if (ret) { 51 pr_debug("%s: error %d reading SDIO_CCCR_INTx\n", 52 mmc_card_id(card), ret); 53 return ret; 54 } 55 56 if (pending && mmc_card_broken_irq_polling(card) && 57 !(host->caps & MMC_CAP_SDIO_IRQ)) { 58 unsigned char dummy; 59 60 /* A fake interrupt could be created when we poll SDIO_CCCR_INTx 61 * register with a Marvell SD8797 card. A dummy CMD52 read to 62 * function 0 register 0xff can avoid this. 63 */ 64 mmc_io_rw_direct(card, 0, 0, 0xff, 0, &dummy); 65 } 66 67 count = 0; 68 for (i = 1; i <= 7; i++) { 69 if (pending & (1 << i)) { 70 func = card->sdio_func[i - 1]; 71 if (!func) { 72 pr_warn("%s: pending IRQ for non-existent function\n", 73 mmc_card_id(card)); 74 ret = -EINVAL; 75 } else if (func->irq_handler) { 76 func->irq_handler(func); 77 count++; 78 } else { 79 pr_warn("%s: pending IRQ with no handler\n", 80 sdio_func_id(func)); 81 ret = -EINVAL; 82 } 83 } 84 } 85 86 if (count) 87 return count; 88 89 return ret; 90 } 91 92 void sdio_run_irqs(struct mmc_host *host) 93 { 94 mmc_claim_host(host); 95 host->sdio_irq_pending = true; 96 process_sdio_pending_irqs(host); 97 mmc_release_host(host); 98 } 99 EXPORT_SYMBOL_GPL(sdio_run_irqs); 100 101 static int sdio_irq_thread(void *_host) 102 { 103 struct mmc_host *host = _host; 104 struct sched_param param = { .sched_priority = 1 }; 105 unsigned long period, idle_period; 106 int ret; 107 108 sched_setscheduler(current, SCHED_FIFO, ¶m); 109 110 /* 111 * We want to allow for SDIO cards to work even on non SDIO 112 * aware hosts. One thing that non SDIO host cannot do is 113 * asynchronous notification of pending SDIO card interrupts 114 * hence we poll for them in that case. 115 */ 116 idle_period = msecs_to_jiffies(10); 117 period = (host->caps & MMC_CAP_SDIO_IRQ) ? 118 MAX_SCHEDULE_TIMEOUT : idle_period; 119 120 pr_debug("%s: IRQ thread started (poll period = %lu jiffies)\n", 121 mmc_hostname(host), period); 122 123 do { 124 /* 125 * We claim the host here on drivers behalf for a couple 126 * reasons: 127 * 128 * 1) it is already needed to retrieve the CCCR_INTx; 129 * 2) we want the driver(s) to clear the IRQ condition ASAP; 130 * 3) we need to control the abort condition locally. 131 * 132 * Just like traditional hard IRQ handlers, we expect SDIO 133 * IRQ handlers to be quick and to the point, so that the 134 * holding of the host lock does not cover too much work 135 * that doesn't require that lock to be held. 136 */ 137 ret = __mmc_claim_host(host, &host->sdio_irq_thread_abort); 138 if (ret) 139 break; 140 ret = process_sdio_pending_irqs(host); 141 host->sdio_irq_pending = false; 142 mmc_release_host(host); 143 144 /* 145 * Give other threads a chance to run in the presence of 146 * errors. 147 */ 148 if (ret < 0) { 149 set_current_state(TASK_INTERRUPTIBLE); 150 if (!kthread_should_stop()) 151 schedule_timeout(HZ); 152 set_current_state(TASK_RUNNING); 153 } 154 155 /* 156 * Adaptive polling frequency based on the assumption 157 * that an interrupt will be closely followed by more. 158 * This has a substantial benefit for network devices. 159 */ 160 if (!(host->caps & MMC_CAP_SDIO_IRQ)) { 161 if (ret > 0) 162 period /= 2; 163 else { 164 period++; 165 if (period > idle_period) 166 period = idle_period; 167 } 168 } 169 170 set_current_state(TASK_INTERRUPTIBLE); 171 if (host->caps & MMC_CAP_SDIO_IRQ) { 172 mmc_host_clk_hold(host); 173 host->ops->enable_sdio_irq(host, 1); 174 mmc_host_clk_release(host); 175 } 176 if (!kthread_should_stop()) 177 schedule_timeout(period); 178 set_current_state(TASK_RUNNING); 179 } while (!kthread_should_stop()); 180 181 if (host->caps & MMC_CAP_SDIO_IRQ) { 182 mmc_host_clk_hold(host); 183 host->ops->enable_sdio_irq(host, 0); 184 mmc_host_clk_release(host); 185 } 186 187 pr_debug("%s: IRQ thread exiting with code %d\n", 188 mmc_hostname(host), ret); 189 190 return ret; 191 } 192 193 static int sdio_card_irq_get(struct mmc_card *card) 194 { 195 struct mmc_host *host = card->host; 196 197 WARN_ON(!host->claimed); 198 199 if (!host->sdio_irqs++) { 200 if (!(host->caps2 & MMC_CAP2_SDIO_IRQ_NOTHREAD)) { 201 atomic_set(&host->sdio_irq_thread_abort, 0); 202 host->sdio_irq_thread = 203 kthread_run(sdio_irq_thread, host, 204 "ksdioirqd/%s", mmc_hostname(host)); 205 if (IS_ERR(host->sdio_irq_thread)) { 206 int err = PTR_ERR(host->sdio_irq_thread); 207 host->sdio_irqs--; 208 return err; 209 } 210 } else if (host->caps & MMC_CAP_SDIO_IRQ) { 211 mmc_host_clk_hold(host); 212 host->ops->enable_sdio_irq(host, 1); 213 mmc_host_clk_release(host); 214 } 215 } 216 217 return 0; 218 } 219 220 static int sdio_card_irq_put(struct mmc_card *card) 221 { 222 struct mmc_host *host = card->host; 223 224 WARN_ON(!host->claimed); 225 BUG_ON(host->sdio_irqs < 1); 226 227 if (!--host->sdio_irqs) { 228 if (!(host->caps2 & MMC_CAP2_SDIO_IRQ_NOTHREAD)) { 229 atomic_set(&host->sdio_irq_thread_abort, 1); 230 kthread_stop(host->sdio_irq_thread); 231 } else if (host->caps & MMC_CAP_SDIO_IRQ) { 232 mmc_host_clk_hold(host); 233 host->ops->enable_sdio_irq(host, 0); 234 mmc_host_clk_release(host); 235 } 236 } 237 238 return 0; 239 } 240 241 /* If there is only 1 function registered set sdio_single_irq */ 242 static void sdio_single_irq_set(struct mmc_card *card) 243 { 244 struct sdio_func *func; 245 int i; 246 247 card->sdio_single_irq = NULL; 248 if ((card->host->caps & MMC_CAP_SDIO_IRQ) && 249 card->host->sdio_irqs == 1) 250 for (i = 0; i < card->sdio_funcs; i++) { 251 func = card->sdio_func[i]; 252 if (func && func->irq_handler) { 253 card->sdio_single_irq = func; 254 break; 255 } 256 } 257 } 258 259 /** 260 * sdio_claim_irq - claim the IRQ for a SDIO function 261 * @func: SDIO function 262 * @handler: IRQ handler callback 263 * 264 * Claim and activate the IRQ for the given SDIO function. The provided 265 * handler will be called when that IRQ is asserted. The host is always 266 * claimed already when the handler is called so the handler must not 267 * call sdio_claim_host() nor sdio_release_host(). 268 */ 269 int sdio_claim_irq(struct sdio_func *func, sdio_irq_handler_t *handler) 270 { 271 int ret; 272 unsigned char reg; 273 274 BUG_ON(!func); 275 BUG_ON(!func->card); 276 277 pr_debug("SDIO: Enabling IRQ for %s...\n", sdio_func_id(func)); 278 279 if (func->irq_handler) { 280 pr_debug("SDIO: IRQ for %s already in use.\n", sdio_func_id(func)); 281 return -EBUSY; 282 } 283 284 ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, ®); 285 if (ret) 286 return ret; 287 288 reg |= 1 << func->num; 289 290 reg |= 1; /* Master interrupt enable */ 291 292 ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL); 293 if (ret) 294 return ret; 295 296 func->irq_handler = handler; 297 ret = sdio_card_irq_get(func->card); 298 if (ret) 299 func->irq_handler = NULL; 300 sdio_single_irq_set(func->card); 301 302 return ret; 303 } 304 EXPORT_SYMBOL_GPL(sdio_claim_irq); 305 306 /** 307 * sdio_release_irq - release the IRQ for a SDIO function 308 * @func: SDIO function 309 * 310 * Disable and release the IRQ for the given SDIO function. 311 */ 312 int sdio_release_irq(struct sdio_func *func) 313 { 314 int ret; 315 unsigned char reg; 316 317 BUG_ON(!func); 318 BUG_ON(!func->card); 319 320 pr_debug("SDIO: Disabling IRQ for %s...\n", sdio_func_id(func)); 321 322 if (func->irq_handler) { 323 func->irq_handler = NULL; 324 sdio_card_irq_put(func->card); 325 sdio_single_irq_set(func->card); 326 } 327 328 ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, ®); 329 if (ret) 330 return ret; 331 332 reg &= ~(1 << func->num); 333 334 /* Disable master interrupt with the last function interrupt */ 335 if (!(reg & 0xFE)) 336 reg = 0; 337 338 ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL); 339 if (ret) 340 return ret; 341 342 return 0; 343 } 344 EXPORT_SYMBOL_GPL(sdio_release_irq); 345 346