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