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