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 static int sdio_irq_thread(void *_host)
  94 {
  95         struct mmc_host *host = _host;
  96         struct sched_param param = { .sched_priority = 1 };
  97         unsigned long period, idle_period;
  98         int ret;
  99
 100         sched_setscheduler(current, SCHED_FIFO, &param);
 101
 102         /*
 103          * We want to allow for SDIO cards to work even on non SDIO
 104          * aware hosts.  One thing that non SDIO host cannot do is
 105          * asynchronous notification of pending SDIO card interrupts
 106          * hence we poll for them in that case.
 107          */
 108         idle_period = msecs_to_jiffies(10);
 109         period = (host->caps & MMC_CAP_SDIO_IRQ) ?
 110                 MAX_SCHEDULE_TIMEOUT : idle_period;
 111
 112         pr_debug("%s: IRQ thread started (poll period = %lu jiffies)\n",
 113                  mmc_hostname(host), period);
 114
 115         do {
 116                 /*
 117                  * We claim the host here on drivers behalf for a couple
 118                  * reasons:
 119                  *
 120                  * 1) it is already needed to retrieve the CCCR_INTx;
 121                  * 2) we want the driver(s) to clear the IRQ condition ASAP;
 122                  * 3) we need to control the abort condition locally.
 123                  *
 124                  * Just like traditional hard IRQ handlers, we expect SDIO
 125                  * IRQ handlers to be quick and to the point, so that the
 126                  * holding of the host lock does not cover too much work
 127                  * that doesn't require that lock to be held.
 128                  */
 129                 ret = __mmc_claim_host(host, &host->sdio_irq_thread_abort);
 130                 if (ret)
 131                         break;
 132                 ret = process_sdio_pending_irqs(host);
 133                 host->sdio_irq_pending = false;
 134                 mmc_release_host(host);
 135
 136                 /*
 137                  * Give other threads a chance to run in the presence of
 138                  * errors.
 139                  */
 140                 if (ret < 0) {
 141                         set_current_state(TASK_INTERRUPTIBLE);
 142                         if (!kthread_should_stop())
 143                                 schedule_timeout(HZ);
 144                         set_current_state(TASK_RUNNING);
 145                 }
 146
 147                 /*
 148                  * Adaptive polling frequency based on the assumption
 149                  * that an interrupt will be closely followed by more.
 150                  * This has a substantial benefit for network devices.
 151                  */
 152                 if (!(host->caps & MMC_CAP_SDIO_IRQ)) {
 153                         if (ret > 0)
 154                                 period /= 2;
 155                         else {
 156                                 period++;
 157                                 if (period > idle_period)
 158                                         period = idle_period;
 159                         }
 160                 }
 161
 162                 set_current_state(TASK_INTERRUPTIBLE);
 163                 if (host->caps & MMC_CAP_SDIO_IRQ) {
 164                         mmc_host_clk_hold(host);
 165                         host->ops->enable_sdio_irq(host, 1);
 166                         mmc_host_clk_release(host);
 167                 }
 168                 if (!kthread_should_stop())
 169                         schedule_timeout(period);
 170                 set_current_state(TASK_RUNNING);
 171         } while (!kthread_should_stop());
 172
 173         if (host->caps & MMC_CAP_SDIO_IRQ) {
 174                 mmc_host_clk_hold(host);
 175                 host->ops->enable_sdio_irq(host, 0);
 176                 mmc_host_clk_release(host);
 177         }
 178
 179         pr_debug("%s: IRQ thread exiting with code %d\n",
 180                  mmc_hostname(host), ret);
 181
 182         return ret;
 183 }
 184
 185 static int sdio_card_irq_get(struct mmc_card *card)
 186 {
 187         struct mmc_host *host = card->host;
 188
 189         WARN_ON(!host->claimed);
 190
 191         if (!host->sdio_irqs++) {
 192                 atomic_set(&host->sdio_irq_thread_abort, 0);
 193                 host->sdio_irq_thread =
 194                         kthread_run(sdio_irq_thread, host, "ksdioirqd/%s",
 195                                 mmc_hostname(host));
 196                 if (IS_ERR(host->sdio_irq_thread)) {
 197                         int err = PTR_ERR(host->sdio_irq_thread);
 198                         host->sdio_irqs--;
 199                         return err;
 200                 }
 201         }
 202
 203         return 0;
 204 }
 205
 206 static int sdio_card_irq_put(struct mmc_card *card)
 207 {
 208         struct mmc_host *host = card->host;
 209
 210         WARN_ON(!host->claimed);
 211         BUG_ON(host->sdio_irqs < 1);
 212
 213         if (!--host->sdio_irqs) {
 214                 atomic_set(&host->sdio_irq_thread_abort, 1);
 215                 kthread_stop(host->sdio_irq_thread);
 216         }
 217
 218         return 0;
 219 }
 220
 221 /* If there is only 1 function registered set sdio_single_irq */
 222 static void sdio_single_irq_set(struct mmc_card *card)
 223 {
 224         struct sdio_func *func;
 225         int i;
 226
 227         card->sdio_single_irq = NULL;
 228         if ((card->host->caps & MMC_CAP_SDIO_IRQ) &&
 229             card->host->sdio_irqs == 1)
 230                 for (i = 0; i < card->sdio_funcs; i++) {
 231                        func = card->sdio_func[i];
 232                        if (func && func->irq_handler) {
 233                                card->sdio_single_irq = func;
 234                                break;
 235                        }
 236                }
 237 }
 238
 239 /**
 240  *      sdio_claim_irq - claim the IRQ for a SDIO function
 241  *      @func: SDIO function
 242  *      @handler: IRQ handler callback
 243  *
 244  *      Claim and activate the IRQ for the given SDIO function. The provided
 245  *      handler will be called when that IRQ is asserted.  The host is always
 246  *      claimed already when the handler is called so the handler must not
 247  *      call sdio_claim_host() nor sdio_release_host().
 248  */
 249 int sdio_claim_irq(struct sdio_func *func, sdio_irq_handler_t *handler)
 250 {
 251         int ret;
 252         unsigned char reg;
 253
 254         BUG_ON(!func);
 255         BUG_ON(!func->card);
 256
 257         pr_debug("SDIO: Enabling IRQ for %s...\n", sdio_func_id(func));
 258
 259         if (func->irq_handler) {
 260                 pr_debug("SDIO: IRQ for %s already in use.\n", sdio_func_id(func));
 261                 return -EBUSY;
 262         }
 263
 264         ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, &reg);
 265         if (ret)
 266                 return ret;
 267
 268         reg |= 1 << func->num;
 269
 270         reg |= 1; /* Master interrupt enable */
 271
 272         ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
 273         if (ret)
 274                 return ret;
 275
 276         func->irq_handler = handler;
 277         ret = sdio_card_irq_get(func->card);
 278         if (ret)
 279                 func->irq_handler = NULL;
 280         sdio_single_irq_set(func->card);
 281
 282         return ret;
 283 }
 284 EXPORT_SYMBOL_GPL(sdio_claim_irq);
 285
 286 /**
 287  *      sdio_release_irq - release the IRQ for a SDIO function
 288  *      @func: SDIO function
 289  *
 290  *      Disable and release the IRQ for the given SDIO function.
 291  */
 292 int sdio_release_irq(struct sdio_func *func)
 293 {
 294         int ret;
 295         unsigned char reg;
 296
 297         BUG_ON(!func);
 298         BUG_ON(!func->card);
 299
 300         pr_debug("SDIO: Disabling IRQ for %s...\n", sdio_func_id(func));
 301
 302         if (func->irq_handler) {
 303                 func->irq_handler = NULL;
 304                 sdio_card_irq_put(func->card);
 305                 sdio_single_irq_set(func->card);
 306         }
 307
 308         ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, &reg);
 309         if (ret)
 310                 return ret;
 311
 312         reg &= ~(1 << func->num);
 313
 314         /* Disable master interrupt with the last function interrupt */
 315         if (!(reg & 0xFE))
 316                 reg = 0;
 317
 318         ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
 319         if (ret)
 320                 return ret;
 321
 322         return 0;
 323 }
 324 EXPORT_SYMBOL_GPL(sdio_release_irq);
 325