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 <uapi/linux/sched/types.h>
  19 #include <linux/kthread.h>
  20 #include <linux/export.h>
  21 #include <linux/wait.h>
  22 #include <linux/delay.h>
  23
  24 #include <linux/mmc/core.h>
  25 #include <linux/mmc/host.h>
  26 #include <linux/mmc/card.h>
  27 #include <linux/mmc/sdio.h>
  28 #include <linux/mmc/sdio_func.h>
  29
  30 #include "sdio_ops.h"
  31 #include "core.h"
  32 #include "card.h"
  33
  34 static int process_sdio_pending_irqs(struct mmc_host *host)
  35 {
  36         struct mmc_card *card = host->card;
  37         int i, ret, count;
  38         unsigned char pending;
  39         struct sdio_func *func;
  40
  41         /*
  42          * Optimization, if there is only 1 function interrupt registered
  43          * and we know an IRQ was signaled then call irq handler directly.
  44          * Otherwise do the full probe.
  45          */
  46         func = card->sdio_single_irq;
  47         if (func && host->sdio_irq_pending) {
  48                 func->irq_handler(func);
  49                 return 1;
  50         }
  51
  52         ret = mmc_io_rw_direct(card, 0, 0, SDIO_CCCR_INTx, 0, &pending);
  53         if (ret) {
  54                 pr_debug("%s: error %d reading SDIO_CCCR_INTx\n",
  55                        mmc_card_id(card), ret);
  56                 return ret;
  57         }
  58
  59         if (pending && mmc_card_broken_irq_polling(card) &&
  60             !(host->caps & MMC_CAP_SDIO_IRQ)) {
  61                 unsigned char dummy;
  62
  63                 /* A fake interrupt could be created when we poll SDIO_CCCR_INTx
  64                  * register with a Marvell SD8797 card. A dummy CMD52 read to
  65                  * function 0 register 0xff can avoid this.
  66                  */
  67                 mmc_io_rw_direct(card, 0, 0, 0xff, 0, &dummy);
  68         }
  69
  70         count = 0;
  71         for (i = 1; i <= 7; i++) {
  72                 if (pending & (1 << i)) {
  73                         func = card->sdio_func[i - 1];
  74                         if (!func) {
  75                                 pr_warn("%s: pending IRQ for non-existent function\n",
  76                                         mmc_card_id(card));
  77                                 ret = -EINVAL;
  78                         } else if (func->irq_handler) {
  79                                 func->irq_handler(func);
  80                                 count++;
  81                         } else {
  82                                 pr_warn("%s: pending IRQ with no handler\n",
  83                                         sdio_func_id(func));
  84                                 ret = -EINVAL;
  85                         }
  86                 }
  87         }
  88
  89         if (count)
  90                 return count;
  91
  92         return ret;
  93 }
  94
  95 void sdio_run_irqs(struct mmc_host *host)
  96 {
  97         mmc_claim_host(host);
  98         if (host->sdio_irqs) {
  99                 host->sdio_irq_pending = true;
 100                 process_sdio_pending_irqs(host);
 101                 if (host->ops->ack_sdio_irq)
 102                         host->ops->ack_sdio_irq(host);
 103         }
 104         mmc_release_host(host);
 105 }
 106 EXPORT_SYMBOL_GPL(sdio_run_irqs);
 107
 108 void sdio_irq_work(struct work_struct *work)
 109 {
 110         struct mmc_host *host =
 111                 container_of(work, struct mmc_host, sdio_irq_work.work);
 112
 113         sdio_run_irqs(host);
 114 }
 115
 116 void sdio_signal_irq(struct mmc_host *host)
 117 {
 118         queue_delayed_work(system_wq, &host->sdio_irq_work, 0);
 119 }
 120 EXPORT_SYMBOL_GPL(sdio_signal_irq);
 121
 122 static int sdio_irq_thread(void *_host)
 123 {
 124         struct mmc_host *host = _host;
 125         struct sched_param param = { .sched_priority = 1 };
 126         unsigned long period, idle_period;
 127         int ret;
 128
 129         sched_setscheduler(current, SCHED_FIFO, &param);
 130
 131         /*
 132          * We want to allow for SDIO cards to work even on non SDIO
 133          * aware hosts.  One thing that non SDIO host cannot do is
 134          * asynchronous notification of pending SDIO card interrupts
 135          * hence we poll for them in that case.
 136          */
 137         idle_period = msecs_to_jiffies(10);
 138         period = (host->caps & MMC_CAP_SDIO_IRQ) ?
 139                 MAX_SCHEDULE_TIMEOUT : idle_period;
 140
 141         pr_debug("%s: IRQ thread started (poll period = %lu jiffies)\n",
 142                  mmc_hostname(host), period);
 143
 144         do {
 145                 /*
 146                  * We claim the host here on drivers behalf for a couple
 147                  * reasons:
 148                  *
 149                  * 1) it is already needed to retrieve the CCCR_INTx;
 150                  * 2) we want the driver(s) to clear the IRQ condition ASAP;
 151                  * 3) we need to control the abort condition locally.
 152                  *
 153                  * Just like traditional hard IRQ handlers, we expect SDIO
 154                  * IRQ handlers to be quick and to the point, so that the
 155                  * holding of the host lock does not cover too much work
 156                  * that doesn't require that lock to be held.
 157                  */
 158                 ret = __mmc_claim_host(host, NULL,
 159                                        &host->sdio_irq_thread_abort);
 160                 if (ret)
 161                         break;
 162                 ret = process_sdio_pending_irqs(host);
 163                 host->sdio_irq_pending = false;
 164                 mmc_release_host(host);
 165
 166                 /*
 167                  * Give other threads a chance to run in the presence of
 168                  * errors.
 169                  */
 170                 if (ret < 0) {
 171                         set_current_state(TASK_INTERRUPTIBLE);
 172                         if (!kthread_should_stop())
 173                                 schedule_timeout(HZ);
 174                         set_current_state(TASK_RUNNING);
 175                 }
 176
 177                 /*
 178                  * Adaptive polling frequency based on the assumption
 179                  * that an interrupt will be closely followed by more.
 180                  * This has a substantial benefit for network devices.
 181                  */
 182                 if (!(host->caps & MMC_CAP_SDIO_IRQ)) {
 183                         if (ret > 0)
 184                                 period /= 2;
 185                         else {
 186                                 period++;
 187                                 if (period > idle_period)
 188                                         period = idle_period;
 189                         }
 190                 }
 191
 192                 set_current_state(TASK_INTERRUPTIBLE);
 193                 if (host->caps & MMC_CAP_SDIO_IRQ)
 194                         host->ops->enable_sdio_irq(host, 1);
 195                 if (!kthread_should_stop())
 196                         schedule_timeout(period);
 197                 set_current_state(TASK_RUNNING);
 198         } while (!kthread_should_stop());
 199
 200         if (host->caps & MMC_CAP_SDIO_IRQ)
 201                 host->ops->enable_sdio_irq(host, 0);
 202
 203         pr_debug("%s: IRQ thread exiting with code %d\n",
 204                  mmc_hostname(host), ret);
 205
 206         return ret;
 207 }
 208
 209 static int sdio_card_irq_get(struct mmc_card *card)
 210 {
 211         struct mmc_host *host = card->host;
 212
 213         WARN_ON(!host->claimed);
 214
 215         if (!host->sdio_irqs++) {
 216                 if (!(host->caps2 & MMC_CAP2_SDIO_IRQ_NOTHREAD)) {
 217                         atomic_set(&host->sdio_irq_thread_abort, 0);
 218                         host->sdio_irq_thread =
 219                                 kthread_run(sdio_irq_thread, host,
 220                                             "ksdioirqd/%s", mmc_hostname(host));
 221                         if (IS_ERR(host->sdio_irq_thread)) {
 222                                 int err = PTR_ERR(host->sdio_irq_thread);
 223                                 host->sdio_irqs--;
 224                                 return err;
 225                         }
 226                 } else if (host->caps & MMC_CAP_SDIO_IRQ) {
 227                         host->ops->enable_sdio_irq(host, 1);
 228                 }
 229         }
 230
 231         return 0;
 232 }
 233
 234 static int sdio_card_irq_put(struct mmc_card *card)
 235 {
 236         struct mmc_host *host = card->host;
 237
 238         WARN_ON(!host->claimed);
 239
 240         if (host->sdio_irqs < 1)
 241                 return -EINVAL;
 242
 243         if (!--host->sdio_irqs) {
 244                 if (!(host->caps2 & MMC_CAP2_SDIO_IRQ_NOTHREAD)) {
 245                         atomic_set(&host->sdio_irq_thread_abort, 1);
 246                         kthread_stop(host->sdio_irq_thread);
 247                 } else if (host->caps & MMC_CAP_SDIO_IRQ) {
 248                         host->ops->enable_sdio_irq(host, 0);
 249                 }
 250         }
 251
 252         return 0;
 253 }
 254
 255 /* If there is only 1 function registered set sdio_single_irq */
 256 static void sdio_single_irq_set(struct mmc_card *card)
 257 {
 258         struct sdio_func *func;
 259         int i;
 260
 261         card->sdio_single_irq = NULL;
 262         if ((card->host->caps & MMC_CAP_SDIO_IRQ) &&
 263             card->host->sdio_irqs == 1)
 264                 for (i = 0; i < card->sdio_funcs; i++) {
 265                        func = card->sdio_func[i];
 266                        if (func && func->irq_handler) {
 267                                card->sdio_single_irq = func;
 268                                break;
 269                        }
 270                }
 271 }
 272
 273 /**
 274  *      sdio_claim_irq - claim the IRQ for a SDIO function
 275  *      @func: SDIO function
 276  *      @handler: IRQ handler callback
 277  *
 278  *      Claim and activate the IRQ for the given SDIO function. The provided
 279  *      handler will be called when that IRQ is asserted.  The host is always
 280  *      claimed already when the handler is called so the handler must not
 281  *      call sdio_claim_host() nor sdio_release_host().
 282  */
 283 int sdio_claim_irq(struct sdio_func *func, sdio_irq_handler_t *handler)
 284 {
 285         int ret;
 286         unsigned char reg;
 287
 288         if (!func)
 289                 return -EINVAL;
 290
 291         pr_debug("SDIO: Enabling IRQ for %s...\n", sdio_func_id(func));
 292
 293         if (func->irq_handler) {
 294                 pr_debug("SDIO: IRQ for %s already in use.\n", sdio_func_id(func));
 295                 return -EBUSY;
 296         }
 297
 298         ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, &reg);
 299         if (ret)
 300                 return ret;
 301
 302         reg |= 1 << func->num;
 303
 304         reg |= 1; /* Master interrupt enable */
 305
 306         ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
 307         if (ret)
 308                 return ret;
 309
 310         func->irq_handler = handler;
 311         ret = sdio_card_irq_get(func->card);
 312         if (ret)
 313                 func->irq_handler = NULL;
 314         sdio_single_irq_set(func->card);
 315
 316         return ret;
 317 }
 318 EXPORT_SYMBOL_GPL(sdio_claim_irq);
 319
 320 /**
 321  *      sdio_release_irq - release the IRQ for a SDIO function
 322  *      @func: SDIO function
 323  *
 324  *      Disable and release the IRQ for the given SDIO function.
 325  */
 326 int sdio_release_irq(struct sdio_func *func)
 327 {
 328         int ret;
 329         unsigned char reg;
 330
 331         if (!func)
 332                 return -EINVAL;
 333
 334         pr_debug("SDIO: Disabling IRQ for %s...\n", sdio_func_id(func));
 335
 336         if (func->irq_handler) {
 337                 func->irq_handler = NULL;
 338                 sdio_card_irq_put(func->card);
 339                 sdio_single_irq_set(func->card);
 340         }
 341
 342         ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, &reg);
 343         if (ret)
 344                 return ret;
 345
 346         reg &= ~(1 << func->num);
 347
 348         /* Disable master interrupt with the last function interrupt */
 349         if (!(reg & 0xFE))
 350                 reg = 0;
 351
 352         ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
 353         if (ret)
 354                 return ret;
 355
 356         return 0;
 357 }
 358 EXPORT_SYMBOL_GPL(sdio_release_irq);
 359