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  * 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, &param);
  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_task_state(current, 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_task_state(current, 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, &reg);
 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, &reg);
 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