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/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, &param);
  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                         host->ops->enable_sdio_irq(host, 1);
 154                 if (!kthread_should_stop())
 155                         schedule_timeout(period);
 156                 set_current_state(TASK_RUNNING);
 157         } while (!kthread_should_stop());
 158
 159         if (host->caps & MMC_CAP_SDIO_IRQ)
 160                 host->ops->enable_sdio_irq(host, 0);
 161
 162         pr_debug("%s: IRQ thread exiting with code %d\n",
 163                  mmc_hostname(host), ret);
 164
 165         return ret;
 166 }
 167
 168 static int sdio_card_irq_get(struct mmc_card *card)
 169 {
 170         struct mmc_host *host = card->host;
 171
 172         WARN_ON(!host->claimed);
 173
 174         if (!host->sdio_irqs++) {
 175                 atomic_set(&host->sdio_irq_thread_abort, 0);
 176                 host->sdio_irq_thread =
 177                         kthread_run(sdio_irq_thread, host, "ksdioirqd/%s",
 178                                 mmc_hostname(host));
 179                 if (IS_ERR(host->sdio_irq_thread)) {
 180                         int err = PTR_ERR(host->sdio_irq_thread);
 181                         host->sdio_irqs--;
 182                         return err;
 183                 }
 184         }
 185
 186         return 0;
 187 }
 188
 189 static int sdio_card_irq_put(struct mmc_card *card)
 190 {
 191         struct mmc_host *host = card->host;
 192
 193         WARN_ON(!host->claimed);
 194         BUG_ON(host->sdio_irqs < 1);
 195
 196         if (!--host->sdio_irqs) {
 197                 atomic_set(&host->sdio_irq_thread_abort, 1);
 198                 kthread_stop(host->sdio_irq_thread);
 199         }
 200
 201         return 0;
 202 }
 203
 204 /* If there is only 1 function registered set sdio_single_irq */
 205 static void sdio_single_irq_set(struct mmc_card *card)
 206 {
 207         struct sdio_func *func;
 208         int i;
 209
 210         card->sdio_single_irq = NULL;
 211         if ((card->host->caps & MMC_CAP_SDIO_IRQ) &&
 212             card->host->sdio_irqs == 1)
 213                 for (i = 0; i < card->sdio_funcs; i++) {
 214                        func = card->sdio_func[i];
 215                        if (func && func->irq_handler) {
 216                                card->sdio_single_irq = func;
 217                                break;
 218                        }
 219                }
 220 }
 221
 222 /**
 223  *      sdio_claim_irq - claim the IRQ for a SDIO function
 224  *      @func: SDIO function
 225  *      @handler: IRQ handler callback
 226  *
 227  *      Claim and activate the IRQ for the given SDIO function. The provided
 228  *      handler will be called when that IRQ is asserted.  The host is always
 229  *      claimed already when the handler is called so the handler must not
 230  *      call sdio_claim_host() nor sdio_release_host().
 231  */
 232 int sdio_claim_irq(struct sdio_func *func, sdio_irq_handler_t *handler)
 233 {
 234         int ret;
 235         unsigned char reg;
 236
 237         BUG_ON(!func);
 238         BUG_ON(!func->card);
 239
 240         pr_debug("SDIO: Enabling IRQ for %s...\n", sdio_func_id(func));
 241
 242         if (func->irq_handler) {
 243                 pr_debug("SDIO: IRQ for %s already in use.\n", sdio_func_id(func));
 244                 return -EBUSY;
 245         }
 246
 247         ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, &reg);
 248         if (ret)
 249                 return ret;
 250
 251         reg |= 1 << func->num;
 252
 253         reg |= 1; /* Master interrupt enable */
 254
 255         ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
 256         if (ret)
 257                 return ret;
 258
 259         func->irq_handler = handler;
 260         ret = sdio_card_irq_get(func->card);
 261         if (ret)
 262                 func->irq_handler = NULL;
 263         sdio_single_irq_set(func->card);
 264
 265         return ret;
 266 }
 267 EXPORT_SYMBOL_GPL(sdio_claim_irq);
 268
 269 /**
 270  *      sdio_release_irq - release the IRQ for a SDIO function
 271  *      @func: SDIO function
 272  *
 273  *      Disable and release the IRQ for the given SDIO function.
 274  */
 275 int sdio_release_irq(struct sdio_func *func)
 276 {
 277         int ret;
 278         unsigned char reg;
 279
 280         BUG_ON(!func);
 281         BUG_ON(!func->card);
 282
 283         pr_debug("SDIO: Disabling IRQ for %s...\n", sdio_func_id(func));
 284
 285         if (func->irq_handler) {
 286                 func->irq_handler = NULL;
 287                 sdio_card_irq_put(func->card);
 288                 sdio_single_irq_set(func->card);
 289         }
 290
 291         ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, &reg);
 292         if (ret)
 293                 return ret;
 294
 295         reg &= ~(1 << func->num);
 296
 297         /* Disable master interrupt with the last function interrupt */
 298         if (!(reg & 0xFE))
 299                 reg = 0;
 300
 301         ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
 302         if (ret)
 303                 return ret;
 304
 305         return 0;
 306 }
 307 EXPORT_SYMBOL_GPL(sdio_release_irq);
 308