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 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License as published by 10 * the Free Software Foundation; either version 2 of the License, or (at 11 * your option) any later version. 12 */ 13 14 #include <linux/kernel.h> 15 #include <linux/sched.h> 16 #include <linux/kthread.h> 17 #include <linux/wait.h> 18 #include <linux/delay.h> 19 20 #include <linux/mmc/core.h> 21 #include <linux/mmc/host.h> 22 #include <linux/mmc/card.h> 23 #include <linux/mmc/sdio.h> 24 #include <linux/mmc/sdio_func.h> 25 26 #include "sdio_ops.h" 27 28 static int process_sdio_pending_irqs(struct mmc_card *card) 29 { 30 int i, ret, count; 31 unsigned char pending; 32 33 ret = mmc_io_rw_direct(card, 0, 0, SDIO_CCCR_INTx, 0, &pending); 34 if (ret) { 35 printk(KERN_DEBUG "%s: error %d reading SDIO_CCCR_INTx\n", 36 mmc_card_id(card), ret); 37 return ret; 38 } 39 40 count = 0; 41 for (i = 1; i <= 7; i++) { 42 if (pending & (1 << i)) { 43 struct sdio_func *func = card->sdio_func[i - 1]; 44 if (!func) { 45 printk(KERN_WARNING "%s: pending IRQ for " 46 "non-existant function\n", 47 mmc_card_id(card)); 48 ret = -EINVAL; 49 } else if (func->irq_handler) { 50 func->irq_handler(func); 51 count++; 52 } else { 53 printk(KERN_WARNING "%s: pending IRQ with no handler\n", 54 sdio_func_id(func)); 55 ret = -EINVAL; 56 } 57 } 58 } 59 60 if (count) 61 return count; 62 63 return ret; 64 } 65 66 static int sdio_irq_thread(void *_host) 67 { 68 struct mmc_host *host = _host; 69 struct sched_param param = { .sched_priority = 1 }; 70 unsigned long period, idle_period; 71 int ret; 72 73 sched_setscheduler(current, SCHED_FIFO, ¶m); 74 75 /* 76 * We want to allow for SDIO cards to work even on non SDIO 77 * aware hosts. One thing that non SDIO host cannot do is 78 * asynchronous notification of pending SDIO card interrupts 79 * hence we poll for them in that case. 80 */ 81 idle_period = msecs_to_jiffies(10); 82 period = (host->caps & MMC_CAP_SDIO_IRQ) ? 83 MAX_SCHEDULE_TIMEOUT : idle_period; 84 85 pr_debug("%s: IRQ thread started (poll period = %lu jiffies)\n", 86 mmc_hostname(host), period); 87 88 do { 89 /* 90 * We claim the host here on drivers behalf for a couple 91 * reasons: 92 * 93 * 1) it is already needed to retrieve the CCCR_INTx; 94 * 2) we want the driver(s) to clear the IRQ condition ASAP; 95 * 3) we need to control the abort condition locally. 96 * 97 * Just like traditional hard IRQ handlers, we expect SDIO 98 * IRQ handlers to be quick and to the point, so that the 99 * holding of the host lock does not cover too much work 100 * that doesn't require that lock to be held. 101 */ 102 ret = __mmc_claim_host(host, &host->sdio_irq_thread_abort); 103 if (ret) 104 break; 105 ret = process_sdio_pending_irqs(host->card); 106 mmc_release_host(host); 107 108 /* 109 * Give other threads a chance to run in the presence of 110 * errors. FIXME: determine if due to card removal and 111 * possibly exit this thread if so. 112 */ 113 if (ret < 0) 114 ssleep(1); 115 116 /* 117 * Adaptive polling frequency based on the assumption 118 * that an interrupt will be closely followed by more. 119 * This has a substantial benefit for network devices. 120 */ 121 if (!(host->caps & MMC_CAP_SDIO_IRQ)) { 122 if (ret > 0) 123 period /= 2; 124 else { 125 period++; 126 if (period > idle_period) 127 period = idle_period; 128 } 129 } 130 131 set_current_state(TASK_INTERRUPTIBLE); 132 if (host->caps & MMC_CAP_SDIO_IRQ) 133 host->ops->enable_sdio_irq(host, 1); 134 if (!kthread_should_stop()) 135 schedule_timeout(period); 136 set_current_state(TASK_RUNNING); 137 } while (!kthread_should_stop()); 138 139 if (host->caps & MMC_CAP_SDIO_IRQ) 140 host->ops->enable_sdio_irq(host, 0); 141 142 pr_debug("%s: IRQ thread exiting with code %d\n", 143 mmc_hostname(host), ret); 144 145 return ret; 146 } 147 148 static int sdio_card_irq_get(struct mmc_card *card) 149 { 150 struct mmc_host *host = card->host; 151 152 WARN_ON(!host->claimed); 153 154 if (!host->sdio_irqs++) { 155 atomic_set(&host->sdio_irq_thread_abort, 0); 156 host->sdio_irq_thread = 157 kthread_run(sdio_irq_thread, host, "ksdiorqd"); 158 if (IS_ERR(host->sdio_irq_thread)) { 159 int err = PTR_ERR(host->sdio_irq_thread); 160 host->sdio_irqs--; 161 return err; 162 } 163 } 164 165 return 0; 166 } 167 168 static int sdio_card_irq_put(struct mmc_card *card) 169 { 170 struct mmc_host *host = card->host; 171 172 WARN_ON(!host->claimed); 173 BUG_ON(host->sdio_irqs < 1); 174 175 if (!--host->sdio_irqs) { 176 atomic_set(&host->sdio_irq_thread_abort, 1); 177 kthread_stop(host->sdio_irq_thread); 178 } 179 180 return 0; 181 } 182 183 /** 184 * sdio_claim_irq - claim the IRQ for a SDIO function 185 * @func: SDIO function 186 * @handler: IRQ handler callback 187 * 188 * Claim and activate the IRQ for the given SDIO function. The provided 189 * handler will be called when that IRQ is asserted. The host is always 190 * claimed already when the handler is called so the handler must not 191 * call sdio_claim_host() nor sdio_release_host(). 192 */ 193 int sdio_claim_irq(struct sdio_func *func, sdio_irq_handler_t *handler) 194 { 195 int ret; 196 unsigned char reg; 197 198 BUG_ON(!func); 199 BUG_ON(!func->card); 200 201 pr_debug("SDIO: Enabling IRQ for %s...\n", sdio_func_id(func)); 202 203 if (func->irq_handler) { 204 pr_debug("SDIO: IRQ for %s already in use.\n", sdio_func_id(func)); 205 return -EBUSY; 206 } 207 208 ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, ®); 209 if (ret) 210 return ret; 211 212 reg |= 1 << func->num; 213 214 reg |= 1; /* Master interrupt enable */ 215 216 ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL); 217 if (ret) 218 return ret; 219 220 func->irq_handler = handler; 221 ret = sdio_card_irq_get(func->card); 222 if (ret) 223 func->irq_handler = NULL; 224 225 return ret; 226 } 227 EXPORT_SYMBOL_GPL(sdio_claim_irq); 228 229 /** 230 * sdio_release_irq - release the IRQ for a SDIO function 231 * @func: SDIO function 232 * 233 * Disable and release the IRQ for the given SDIO function. 234 */ 235 int sdio_release_irq(struct sdio_func *func) 236 { 237 int ret; 238 unsigned char reg; 239 240 BUG_ON(!func); 241 BUG_ON(!func->card); 242 243 pr_debug("SDIO: Disabling IRQ for %s...\n", sdio_func_id(func)); 244 245 if (func->irq_handler) { 246 func->irq_handler = NULL; 247 sdio_card_irq_put(func->card); 248 } 249 250 ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, ®); 251 if (ret) 252 return ret; 253 254 reg &= ~(1 << func->num); 255 256 /* Disable master interrupt with the last function interrupt */ 257 if (!(reg & 0xFE)) 258 reg = 0; 259 260 ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL); 261 if (ret) 262 return ret; 263 264 return 0; 265 } 266 EXPORT_SYMBOL_GPL(sdio_release_irq); 267 268