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_card *card)
  32 {
  33         int i, ret, count;
  34         unsigned char pending;
  35         struct sdio_func *func;
  36
  37         /*
  38          * Optimization, if there is only 1 function interrupt registered
  39          * call irq handler directly
  40          */
  41         func = card->sdio_single_irq;
  42         if (func) {
  43                 func->irq_handler(func);
  44                 return 1;
  45         }
  46
  47         ret = mmc_io_rw_direct(card, 0, 0, SDIO_CCCR_INTx, 0, &pending);
  48         if (ret) {
  49                 printk(KERN_DEBUG "%s: error %d reading SDIO_CCCR_INTx\n",
  50                        mmc_card_id(card), ret);
  51                 return ret;
  52         }
  53
  54         count = 0;
  55         for (i = 1; i <= 7; i++) {
  56                 if (pending & (1 << i)) {
  57                         func = card->sdio_func[i - 1];
  58                         if (!func) {
  59                                 printk(KERN_WARNING "%s: pending IRQ for "
  60                                         "non-existent function\n",
  61                                         mmc_card_id(card));
  62                                 ret = -EINVAL;
  63                         } else if (func->irq_handler) {
  64                                 func->irq_handler(func);
  65                                 count++;
  66                         } else {
  67                                 printk(KERN_WARNING "%s: pending IRQ with no handler\n",
  68                                        sdio_func_id(func));
  69                                 ret = -EINVAL;
  70                         }
  71                 }
  72         }
  73
  74         if (count)
  75                 return count;
  76
  77         return ret;
  78 }
  79
  80 static int sdio_irq_thread(void *_host)
  81 {
  82         struct mmc_host *host = _host;
  83         struct sched_param param = { .sched_priority = 1 };
  84         unsigned long period, idle_period;
  85         int ret;
  86
  87         sched_setscheduler(current, SCHED_FIFO, &param);
  88
  89         /*
  90          * We want to allow for SDIO cards to work even on non SDIO
  91          * aware hosts.  One thing that non SDIO host cannot do is
  92          * asynchronous notification of pending SDIO card interrupts
  93          * hence we poll for them in that case.
  94          */
  95         idle_period = msecs_to_jiffies(10);
  96         period = (host->caps & MMC_CAP_SDIO_IRQ) ?
  97                 MAX_SCHEDULE_TIMEOUT : idle_period;
  98
  99         pr_debug("%s: IRQ thread started (poll period = %lu jiffies)\n",
 100                  mmc_hostname(host), period);
 101
 102         do {
 103                 /*
 104                  * We claim the host here on drivers behalf for a couple
 105                  * reasons:
 106                  *
 107                  * 1) it is already needed to retrieve the CCCR_INTx;
 108                  * 2) we want the driver(s) to clear the IRQ condition ASAP;
 109                  * 3) we need to control the abort condition locally.
 110                  *
 111                  * Just like traditional hard IRQ handlers, we expect SDIO
 112                  * IRQ handlers to be quick and to the point, so that the
 113                  * holding of the host lock does not cover too much work
 114                  * that doesn't require that lock to be held.
 115                  */
 116                 ret = __mmc_claim_host(host, &host->sdio_irq_thread_abort);
 117                 if (ret)
 118                         break;
 119                 ret = process_sdio_pending_irqs(host->card);
 120                 mmc_release_host(host);
 121
 122                 /*
 123                  * Give other threads a chance to run in the presence of
 124                  * errors.
 125                  */
 126                 if (ret < 0) {
 127                         set_current_state(TASK_INTERRUPTIBLE);
 128                         if (!kthread_should_stop())
 129                                 schedule_timeout(HZ);
 130                         set_current_state(TASK_RUNNING);
 131                 }
 132
 133                 /*
 134                  * Adaptive polling frequency based on the assumption
 135                  * that an interrupt will be closely followed by more.
 136                  * This has a substantial benefit for network devices.
 137                  */
 138                 if (!(host->caps & MMC_CAP_SDIO_IRQ)) {
 139                         if (ret > 0)
 140                                 period /= 2;
 141                         else {
 142                                 period++;
 143                                 if (period > idle_period)
 144                                         period = idle_period;
 145                         }
 146                 }
 147
 148                 set_current_state(TASK_INTERRUPTIBLE);
 149                 if (host->caps & MMC_CAP_SDIO_IRQ)
 150                         host->ops->enable_sdio_irq(host, 1);
 151                 if (!kthread_should_stop())
 152                         schedule_timeout(period);
 153                 set_current_state(TASK_RUNNING);
 154         } while (!kthread_should_stop());
 155
 156         if (host->caps & MMC_CAP_SDIO_IRQ)
 157                 host->ops->enable_sdio_irq(host, 0);
 158
 159         pr_debug("%s: IRQ thread exiting with code %d\n",
 160                  mmc_hostname(host), ret);
 161
 162         return ret;
 163 }
 164
 165 static int sdio_card_irq_get(struct mmc_card *card)
 166 {
 167         struct mmc_host *host = card->host;
 168
 169         WARN_ON(!host->claimed);
 170
 171         if (!host->sdio_irqs++) {
 172                 atomic_set(&host->sdio_irq_thread_abort, 0);
 173                 host->sdio_irq_thread =
 174                         kthread_run(sdio_irq_thread, host, "ksdioirqd/%s",
 175                                 mmc_hostname(host));
 176                 if (IS_ERR(host->sdio_irq_thread)) {
 177                         int err = PTR_ERR(host->sdio_irq_thread);
 178                         host->sdio_irqs--;
 179                         return err;
 180                 }
 181         }
 182
 183         return 0;
 184 }
 185
 186 static int sdio_card_irq_put(struct mmc_card *card)
 187 {
 188         struct mmc_host *host = card->host;
 189
 190         WARN_ON(!host->claimed);
 191         BUG_ON(host->sdio_irqs < 1);
 192
 193         if (!--host->sdio_irqs) {
 194                 atomic_set(&host->sdio_irq_thread_abort, 1);
 195                 kthread_stop(host->sdio_irq_thread);
 196         }
 197
 198         return 0;
 199 }
 200
 201 /* If there is only 1 function registered set sdio_single_irq */
 202 static void sdio_single_irq_set(struct mmc_card *card)
 203 {
 204         struct sdio_func *func;
 205         int i;
 206
 207         card->sdio_single_irq = NULL;
 208         if ((card->host->caps & MMC_CAP_SDIO_IRQ) &&
 209             card->host->sdio_irqs == 1)
 210                 for (i = 0; i < card->sdio_funcs; i++) {
 211                        func = card->sdio_func[i];
 212                        if (func && func->irq_handler) {
 213                                card->sdio_single_irq = func;
 214                                break;
 215                        }
 216                }
 217 }
 218
 219 /**
 220  *      sdio_claim_irq - claim the IRQ for a SDIO function
 221  *      @func: SDIO function
 222  *      @handler: IRQ handler callback
 223  *
 224  *      Claim and activate the IRQ for the given SDIO function. The provided
 225  *      handler will be called when that IRQ is asserted.  The host is always
 226  *      claimed already when the handler is called so the handler must not
 227  *      call sdio_claim_host() nor sdio_release_host().
 228  */
 229 int sdio_claim_irq(struct sdio_func *func, sdio_irq_handler_t *handler)
 230 {
 231         int ret;
 232         unsigned char reg;
 233
 234         BUG_ON(!func);
 235         BUG_ON(!func->card);
 236
 237         pr_debug("SDIO: Enabling IRQ for %s...\n", sdio_func_id(func));
 238
 239         if (func->irq_handler) {
 240                 pr_debug("SDIO: IRQ for %s already in use.\n", sdio_func_id(func));
 241                 return -EBUSY;
 242         }
 243
 244         ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, &reg);
 245         if (ret)
 246                 return ret;
 247
 248         reg |= 1 << func->num;
 249
 250         reg |= 1; /* Master interrupt enable */
 251
 252         ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
 253         if (ret)
 254                 return ret;
 255
 256         func->irq_handler = handler;
 257         ret = sdio_card_irq_get(func->card);
 258         if (ret)
 259                 func->irq_handler = NULL;
 260         sdio_single_irq_set(func->card);
 261
 262         return ret;
 263 }
 264 EXPORT_SYMBOL_GPL(sdio_claim_irq);
 265
 266 /**
 267  *      sdio_release_irq - release the IRQ for a SDIO function
 268  *      @func: SDIO function
 269  *
 270  *      Disable and release the IRQ for the given SDIO function.
 271  */
 272 int sdio_release_irq(struct sdio_func *func)
 273 {
 274         int ret;
 275         unsigned char reg;
 276
 277         BUG_ON(!func);
 278         BUG_ON(!func->card);
 279
 280         pr_debug("SDIO: Disabling IRQ for %s...\n", sdio_func_id(func));
 281
 282         if (func->irq_handler) {
 283                 func->irq_handler = NULL;
 284                 sdio_card_irq_put(func->card);
 285                 sdio_single_irq_set(func->card);
 286         }
 287
 288         ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, &reg);
 289         if (ret)
 290                 return ret;
 291
 292         reg &= ~(1 << func->num);
 293
 294         /* Disable master interrupt with the last function interrupt */
 295         if (!(reg & 0xFE))
 296                 reg = 0;
 297
 298         ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
 299         if (ret)
 300                 return ret;
 301
 302         return 0;
 303 }
 304 EXPORT_SYMBOL_GPL(sdio_release_irq);
 305