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