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