drivers/mmc/core/sdio_irq.c

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