drivers/mmc/core/sdio_irq.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * linux/drivers/mmc/core/sdio_irq.c
   4  *
   5  * Author:      Nicolas Pitre
   6  * Created:     June 18, 2007
   7  * Copyright:   MontaVista Software Inc.
   8  *
   9  * Copyright 2008 Pierre Ossman
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/sched.h>
  14 #include <uapi/linux/sched/types.h>
  15 #include <linux/kthread.h>
  16 #include <linux/export.h>
  17 #include <linux/wait.h>
  18 #include <linux/delay.h>
  19
  20 #include <linux/mmc/core.h>
  21 #include <linux/mmc/host.h>
  22 #include <linux/mmc/card.h>
  23 #include <linux/mmc/sdio.h>
  24 #include <linux/mmc/sdio_func.h>
  25
  26 #include "sdio_ops.h"
  27 #include "core.h"
  28 #include "card.h"
  29
  30 static int process_sdio_pending_irqs(struct mmc_host *host)
  31 {
  32         struct mmc_card *card = host->card;
  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          * and we know an IRQ was signaled then call irq handler directly.
  40          * Otherwise do the full probe.
  41          */
  42         func = card->sdio_single_irq;
  43         if (func && host->sdio_irq_pending) {
  44                 func->irq_handler(func);
  45                 return 1;
  46         }
  47
  48         ret = mmc_io_rw_direct(card, 0, 0, SDIO_CCCR_INTx, 0, &pending);
  49         if (ret) {
  50                 pr_debug("%s: error %d reading SDIO_CCCR_INTx\n",
  51                        mmc_card_id(card), ret);
  52                 return ret;
  53         }
  54
  55         if (pending && mmc_card_broken_irq_polling(card) &&
  56             !(host->caps & MMC_CAP_SDIO_IRQ)) {
  57                 unsigned char dummy;
  58
  59                 /* A fake interrupt could be created when we poll SDIO_CCCR_INTx
  60                  * register with a Marvell SD8797 card. A dummy CMD52 read to
  61                  * function 0 register 0xff can avoid this.
  62                  */
  63                 mmc_io_rw_direct(card, 0, 0, 0xff, 0, &dummy);
  64         }
  65
  66         count = 0;
  67         for (i = 1; i <= 7; i++) {
  68                 if (pending & (1 << i)) {
  69                         func = card->sdio_func[i - 1];
  70                         if (!func) {
  71                                 pr_warn("%s: pending IRQ for non-existent function\n",
  72                                         mmc_card_id(card));
  73                                 ret = -EINVAL;
  74                         } else if (func->irq_handler) {
  75                                 func->irq_handler(func);
  76                                 count++;
  77                         } else {
  78                                 pr_warn("%s: pending IRQ with no handler\n",
  79                                         sdio_func_id(func));
  80                                 ret = -EINVAL;
  81                         }
  82                 }
  83         }
  84
  85         if (count)
  86                 return count;
  87
  88         return ret;
  89 }
  90
  91 void sdio_run_irqs(struct mmc_host *host)
  92 {
  93         mmc_claim_host(host);
  94         if (host->sdio_irqs) {
  95                 host->sdio_irq_pending = true;
  96                 process_sdio_pending_irqs(host);
  97                 if (host->ops->ack_sdio_irq)
  98                         host->ops->ack_sdio_irq(host);
  99         }
 100         mmc_release_host(host);
 101 }
 102 EXPORT_SYMBOL_GPL(sdio_run_irqs);
 103
 104 void sdio_irq_work(struct work_struct *work)
 105 {
 106         struct mmc_host *host =
 107                 container_of(work, struct mmc_host, sdio_irq_work.work);
 108
 109         sdio_run_irqs(host);
 110 }
 111
 112 void sdio_signal_irq(struct mmc_host *host)
 113 {
 114         queue_delayed_work(system_wq, &host->sdio_irq_work, 0);
 115 }
 116 EXPORT_SYMBOL_GPL(sdio_signal_irq);
 117
 118 static int sdio_irq_thread(void *_host)
 119 {
 120         struct mmc_host *host = _host;
 121         struct sched_param param = { .sched_priority = 1 };
 122         unsigned long period, idle_period;
 123         int ret;
 124
 125         sched_setscheduler(current, SCHED_FIFO, &param);
 126
 127         /*
 128          * We want to allow for SDIO cards to work even on non SDIO
 129          * aware hosts.  One thing that non SDIO host cannot do is
 130          * asynchronous notification of pending SDIO card interrupts
 131          * hence we poll for them in that case.
 132          */
 133         idle_period = msecs_to_jiffies(10);
 134         period = (host->caps & MMC_CAP_SDIO_IRQ) ?
 135                 MAX_SCHEDULE_TIMEOUT : idle_period;
 136
 137         pr_debug("%s: IRQ thread started (poll period = %lu jiffies)\n",
 138                  mmc_hostname(host), period);
 139
 140         do {
 141                 /*
 142                  * We claim the host here on drivers behalf for a couple
 143                  * reasons:
 144                  *
 145                  * 1) it is already needed to retrieve the CCCR_INTx;
 146                  * 2) we want the driver(s) to clear the IRQ condition ASAP;
 147                  * 3) we need to control the abort condition locally.
 148                  *
 149                  * Just like traditional hard IRQ handlers, we expect SDIO
 150                  * IRQ handlers to be quick and to the point, so that the
 151                  * holding of the host lock does not cover too much work
 152                  * that doesn't require that lock to be held.
 153                  */
 154                 ret = __mmc_claim_host(host, NULL,
 155                                        &host->sdio_irq_thread_abort);
 156                 if (ret)
 157                         break;
 158                 ret = process_sdio_pending_irqs(host);
 159                 host->sdio_irq_pending = false;
 160                 mmc_release_host(host);
 161
 162                 /*
 163                  * Give other threads a chance to run in the presence of
 164                  * errors.
 165                  */
 166                 if (ret < 0) {
 167                         set_current_state(TASK_INTERRUPTIBLE);
 168                         if (!kthread_should_stop())
 169                                 schedule_timeout(HZ);
 170                         set_current_state(TASK_RUNNING);
 171                 }
 172
 173                 /*
 174                  * Adaptive polling frequency based on the assumption
 175                  * that an interrupt will be closely followed by more.
 176                  * This has a substantial benefit for network devices.
 177                  */
 178                 if (!(host->caps & MMC_CAP_SDIO_IRQ)) {
 179                         if (ret > 0)
 180                                 period /= 2;
 181                         else {
 182                                 period++;
 183                                 if (period > idle_period)
 184                                         period = idle_period;
 185                         }
 186                 }
 187
 188                 set_current_state(TASK_INTERRUPTIBLE);
 189                 if (host->caps & MMC_CAP_SDIO_IRQ)
 190                         host->ops->enable_sdio_irq(host, 1);
 191                 if (!kthread_should_stop())
 192                         schedule_timeout(period);
 193                 set_current_state(TASK_RUNNING);
 194         } while (!kthread_should_stop());
 195
 196         if (host->caps & MMC_CAP_SDIO_IRQ)
 197                 host->ops->enable_sdio_irq(host, 0);
 198
 199         pr_debug("%s: IRQ thread exiting with code %d\n",
 200                  mmc_hostname(host), ret);
 201
 202         return ret;
 203 }
 204
 205 static int sdio_card_irq_get(struct mmc_card *card)
 206 {
 207         struct mmc_host *host = card->host;
 208
 209         WARN_ON(!host->claimed);
 210
 211         if (!host->sdio_irqs++) {
 212                 if (!(host->caps2 & MMC_CAP2_SDIO_IRQ_NOTHREAD)) {
 213                         atomic_set(&host->sdio_irq_thread_abort, 0);
 214                         host->sdio_irq_thread =
 215                                 kthread_run(sdio_irq_thread, host,
 216                                             "ksdioirqd/%s", mmc_hostname(host));
 217                         if (IS_ERR(host->sdio_irq_thread)) {
 218                                 int err = PTR_ERR(host->sdio_irq_thread);
 219                                 host->sdio_irqs--;
 220                                 return err;
 221                         }
 222                 } else if (host->caps & MMC_CAP_SDIO_IRQ) {
 223                         host->ops->enable_sdio_irq(host, 1);
 224                 }
 225         }
 226
 227         return 0;
 228 }
 229
 230 static int sdio_card_irq_put(struct mmc_card *card)
 231 {
 232         struct mmc_host *host = card->host;
 233
 234         WARN_ON(!host->claimed);
 235
 236         if (host->sdio_irqs < 1)
 237                 return -EINVAL;
 238
 239         if (!--host->sdio_irqs) {
 240                 if (!(host->caps2 & MMC_CAP2_SDIO_IRQ_NOTHREAD)) {
 241                         atomic_set(&host->sdio_irq_thread_abort, 1);
 242                         kthread_stop(host->sdio_irq_thread);
 243                 } else if (host->caps & MMC_CAP_SDIO_IRQ) {
 244                         host->ops->enable_sdio_irq(host, 0);
 245                 }
 246         }
 247
 248         return 0;
 249 }
 250
 251 /* If there is only 1 function registered set sdio_single_irq */
 252 static void sdio_single_irq_set(struct mmc_card *card)
 253 {
 254         struct sdio_func *func;
 255         int i;
 256
 257         card->sdio_single_irq = NULL;
 258         if ((card->host->caps & MMC_CAP_SDIO_IRQ) &&
 259             card->host->sdio_irqs == 1)
 260                 for (i = 0; i < card->sdio_funcs; i++) {
 261                        func = card->sdio_func[i];
 262                        if (func && func->irq_handler) {
 263                                card->sdio_single_irq = func;
 264                                break;
 265                        }
 266                }
 267 }
 268
 269 /**
 270  *      sdio_claim_irq - claim the IRQ for a SDIO function
 271  *      @func: SDIO function
 272  *      @handler: IRQ handler callback
 273  *
 274  *      Claim and activate the IRQ for the given SDIO function. The provided
 275  *      handler will be called when that IRQ is asserted.  The host is always
 276  *      claimed already when the handler is called so the handler should not
 277  *      call sdio_claim_host() or sdio_release_host().
 278  */
 279 int sdio_claim_irq(struct sdio_func *func, sdio_irq_handler_t *handler)
 280 {
 281         int ret;
 282         unsigned char reg;
 283
 284         if (!func)
 285                 return -EINVAL;
 286
 287         pr_debug("SDIO: Enabling IRQ for %s...\n", sdio_func_id(func));
 288
 289         if (func->irq_handler) {
 290                 pr_debug("SDIO: IRQ for %s already in use.\n", sdio_func_id(func));
 291                 return -EBUSY;
 292         }
 293
 294         ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, &reg);
 295         if (ret)
 296                 return ret;
 297
 298         reg |= 1 << func->num;
 299
 300         reg |= 1; /* Master interrupt enable */
 301
 302         ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
 303         if (ret)
 304                 return ret;
 305
 306         func->irq_handler = handler;
 307         ret = sdio_card_irq_get(func->card);
 308         if (ret)
 309                 func->irq_handler = NULL;
 310         sdio_single_irq_set(func->card);
 311
 312         return ret;
 313 }
 314 EXPORT_SYMBOL_GPL(sdio_claim_irq);
 315
 316 /**
 317  *      sdio_release_irq - release the IRQ for a SDIO function
 318  *      @func: SDIO function
 319  *
 320  *      Disable and release the IRQ for the given SDIO function.
 321  */
 322 int sdio_release_irq(struct sdio_func *func)
 323 {
 324         int ret;
 325         unsigned char reg;
 326
 327         if (!func)
 328                 return -EINVAL;
 329
 330         pr_debug("SDIO: Disabling IRQ for %s...\n", sdio_func_id(func));
 331
 332         if (func->irq_handler) {
 333                 func->irq_handler = NULL;
 334                 sdio_card_irq_put(func->card);
 335                 sdio_single_irq_set(func->card);
 336         }
 337
 338         ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, &reg);
 339         if (ret)
 340                 return ret;
 341
 342         reg &= ~(1 << func->num);
 343
 344         /* Disable master interrupt with the last function interrupt */
 345         if (!(reg & 0xFE))
 346                 reg = 0;
 347
 348         ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
 349         if (ret)
 350                 return ret;
 351
 352         return 0;
 353 }
 354 EXPORT_SYMBOL_GPL(sdio_release_irq);
 355