drivers/mmc/card/queue.c

   1 /*
   2  *  linux/drivers/mmc/card/queue.c
   3  *
   4  *  Copyright (C) 2003 Russell King, All Rights Reserved.
   5  *  Copyright 2006-2007 Pierre Ossman
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  */
  12 #include <linux/slab.h>
  13 #include <linux/module.h>
  14 #include <linux/blkdev.h>
  15 #include <linux/freezer.h>
  16 #include <linux/kthread.h>
  17 #include <linux/scatterlist.h>
  18
  19 #include <linux/mmc/card.h>
  20 #include <linux/mmc/host.h>
  21 #include "queue.h"
  22
  23 #define MMC_QUEUE_BOUNCESZ      65536
  24
  25 #define MMC_QUEUE_SUSPENDED     (1 << 0)
  26
  27 /*
  28  * Prepare a MMC request. This just filters out odd stuff.
  29  */
  30 static int mmc_prep_request(struct request_queue *q, struct request *req)
  31 {
  32         struct mmc_queue *mq = q->queuedata;
  33
  34         /*
  35          * We only like normal block requests and discards.
  36          */
  37         if (req->cmd_type != REQ_TYPE_FS && !(req->cmd_flags & REQ_DISCARD)) {
  38                 blk_dump_rq_flags(req, "MMC bad request");
  39                 return BLKPREP_KILL;
  40         }
  41
  42         if (mq && mmc_card_removed(mq->card))
  43                 return BLKPREP_KILL;
  44
  45         req->cmd_flags |= REQ_DONTPREP;
  46
  47         return BLKPREP_OK;
  48 }
  49
  50 static int mmc_queue_thread(void *d)
  51 {
  52         struct mmc_queue *mq = d;
  53         struct request_queue *q = mq->queue;
  54
  55         current->flags |= PF_MEMALLOC;
  56
  57         down(&mq->thread_sem);
  58         do {
  59                 struct request *req = NULL;
  60                 struct mmc_queue_req *tmp;
  61
  62                 spin_lock_irq(q->queue_lock);
  63                 set_current_state(TASK_INTERRUPTIBLE);
  64                 req = blk_fetch_request(q);
  65                 mq->mqrq_cur->req = req;
  66                 spin_unlock_irq(q->queue_lock);
  67
  68                 if (req || mq->mqrq_prev->req) {
  69                         set_current_state(TASK_RUNNING);
  70                         mq->issue_fn(mq, req);
  71                 } else {
  72                         if (kthread_should_stop()) {
  73                                 set_current_state(TASK_RUNNING);
  74                                 break;
  75                         }
  76                         up(&mq->thread_sem);
  77                         schedule();
  78                         down(&mq->thread_sem);
  79                 }
  80
  81                 /* Current request becomes previous request and vice versa. */
  82                 mq->mqrq_prev->brq.mrq.data = NULL;
  83                 mq->mqrq_prev->req = NULL;
  84                 tmp = mq->mqrq_prev;
  85                 mq->mqrq_prev = mq->mqrq_cur;
  86                 mq->mqrq_cur = tmp;
  87         } while (1);
  88         up(&mq->thread_sem);
  89
  90         return 0;
  91 }
  92
  93 /*
  94  * Generic MMC request handler.  This is called for any queue on a
  95  * particular host.  When the host is not busy, we look for a request
  96  * on any queue on this host, and attempt to issue it.  This may
  97  * not be the queue we were asked to process.
  98  */
  99 static void mmc_request_fn(struct request_queue *q)
 100 {
 101         struct mmc_queue *mq = q->queuedata;
 102         struct request *req;
 103
 104         if (!mq) {
 105                 while ((req = blk_fetch_request(q)) != NULL) {
 106                         req->cmd_flags |= REQ_QUIET;
 107                         __blk_end_request_all(req, -EIO);
 108                 }
 109                 return;
 110         }
 111
 112         if (!mq->mqrq_cur->req && !mq->mqrq_prev->req)
 113                 wake_up_process(mq->thread);
 114 }
 115
 116 static struct scatterlist *mmc_alloc_sg(int sg_len, int *err)
 117 {
 118         struct scatterlist *sg;
 119
 120         sg = kmalloc(sizeof(struct scatterlist)*sg_len, GFP_KERNEL);
 121         if (!sg)
 122                 *err = -ENOMEM;
 123         else {
 124                 *err = 0;
 125                 sg_init_table(sg, sg_len);
 126         }
 127
 128         return sg;
 129 }
 130
 131 static void mmc_queue_setup_discard(struct request_queue *q,
 132                                     struct mmc_card *card)
 133 {
 134         unsigned max_discard;
 135
 136         max_discard = mmc_calc_max_discard(card);
 137         if (!max_discard)
 138                 return;
 139
 140         queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
 141         q->limits.max_discard_sectors = max_discard;
 142         if (card->erased_byte == 0 && !mmc_can_discard(card))
 143                 q->limits.discard_zeroes_data = 1;
 144         q->limits.discard_granularity = card->pref_erase << 9;
 145         /* granularity must not be greater than max. discard */
 146         if (card->pref_erase > max_discard)
 147                 q->limits.discard_granularity = 0;
 148         if (mmc_can_secure_erase_trim(card) || mmc_can_sanitize(card))
 149                 queue_flag_set_unlocked(QUEUE_FLAG_SECDISCARD, q);
 150 }
 151
 152 /**
 153  * mmc_init_queue - initialise a queue structure.
 154  * @mq: mmc queue
 155  * @card: mmc card to attach this queue
 156  * @lock: queue lock
 157  * @subname: partition subname
 158  *
 159  * Initialise a MMC card request queue.
 160  */
 161 int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card,
 162                    spinlock_t *lock, const char *subname)
 163 {
 164         struct mmc_host *host = card->host;
 165         u64 limit = BLK_BOUNCE_HIGH;
 166         int ret;
 167         struct mmc_queue_req *mqrq_cur = &mq->mqrq[0];
 168         struct mmc_queue_req *mqrq_prev = &mq->mqrq[1];
 169
 170         if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
 171                 limit = *mmc_dev(host)->dma_mask;
 172
 173         mq->card = card;
 174         mq->queue = blk_init_queue(mmc_request_fn, lock);
 175         if (!mq->queue)
 176                 return -ENOMEM;
 177
 178         mq->mqrq_cur = mqrq_cur;
 179         mq->mqrq_prev = mqrq_prev;
 180         mq->queue->queuedata = mq;
 181
 182         blk_queue_prep_rq(mq->queue, mmc_prep_request);
 183         queue_flag_set_unlocked(QUEUE_FLAG_NONROT, mq->queue);
 184         if (mmc_can_erase(card))
 185                 mmc_queue_setup_discard(mq->queue, card);
 186
 187 #ifdef CONFIG_MMC_BLOCK_BOUNCE
 188         if (host->max_segs == 1) {
 189                 unsigned int bouncesz;
 190
 191                 bouncesz = MMC_QUEUE_BOUNCESZ;
 192
 193                 if (bouncesz > host->max_req_size)
 194                         bouncesz = host->max_req_size;
 195                 if (bouncesz > host->max_seg_size)
 196                         bouncesz = host->max_seg_size;
 197                 if (bouncesz > (host->max_blk_count * 512))
 198                         bouncesz = host->max_blk_count * 512;
 199
 200                 if (bouncesz > 512) {
 201                         mqrq_cur->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
 202                         if (!mqrq_cur->bounce_buf) {
 203                                 pr_warning("%s: unable to "
 204                                         "allocate bounce cur buffer\n",
 205                                         mmc_card_name(card));
 206                         }
 207                         mqrq_prev->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
 208                         if (!mqrq_prev->bounce_buf) {
 209                                 pr_warning("%s: unable to "
 210                                         "allocate bounce prev buffer\n",
 211                                         mmc_card_name(card));
 212                                 kfree(mqrq_cur->bounce_buf);
 213                                 mqrq_cur->bounce_buf = NULL;
 214                         }
 215                 }
 216
 217                 if (mqrq_cur->bounce_buf && mqrq_prev->bounce_buf) {
 218                         blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_ANY);
 219                         blk_queue_max_hw_sectors(mq->queue, bouncesz / 512);
 220                         blk_queue_max_segments(mq->queue, bouncesz / 512);
 221                         blk_queue_max_segment_size(mq->queue, bouncesz);
 222
 223                         mqrq_cur->sg = mmc_alloc_sg(1, &ret);
 224                         if (ret)
 225                                 goto cleanup_queue;
 226
 227                         mqrq_cur->bounce_sg =
 228                                 mmc_alloc_sg(bouncesz / 512, &ret);
 229                         if (ret)
 230                                 goto cleanup_queue;
 231
 232                         mqrq_prev->sg = mmc_alloc_sg(1, &ret);
 233                         if (ret)
 234                                 goto cleanup_queue;
 235
 236                         mqrq_prev->bounce_sg =
 237                                 mmc_alloc_sg(bouncesz / 512, &ret);
 238                         if (ret)
 239                                 goto cleanup_queue;
 240                 }
 241         }
 242 #endif
 243
 244         if (!mqrq_cur->bounce_buf && !mqrq_prev->bounce_buf) {
 245                 blk_queue_bounce_limit(mq->queue, limit);
 246                 blk_queue_max_hw_sectors(mq->queue,
 247                         min(host->max_blk_count, host->max_req_size / 512));
 248                 blk_queue_max_segments(mq->queue, host->max_segs);
 249                 blk_queue_max_segment_size(mq->queue, host->max_seg_size);
 250
 251                 mqrq_cur->sg = mmc_alloc_sg(host->max_segs, &ret);
 252                 if (ret)
 253                         goto cleanup_queue;
 254
 255
 256                 mqrq_prev->sg = mmc_alloc_sg(host->max_segs, &ret);
 257                 if (ret)
 258                         goto cleanup_queue;
 259         }
 260
 261         sema_init(&mq->thread_sem, 1);
 262
 263         mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd/%d%s",
 264                 host->index, subname ? subname : "");
 265
 266         if (IS_ERR(mq->thread)) {
 267                 ret = PTR_ERR(mq->thread);
 268                 goto free_bounce_sg;
 269         }
 270
 271         return 0;
 272  free_bounce_sg:
 273         kfree(mqrq_cur->bounce_sg);
 274         mqrq_cur->bounce_sg = NULL;
 275         kfree(mqrq_prev->bounce_sg);
 276         mqrq_prev->bounce_sg = NULL;
 277
 278  cleanup_queue:
 279         kfree(mqrq_cur->sg);
 280         mqrq_cur->sg = NULL;
 281         kfree(mqrq_cur->bounce_buf);
 282         mqrq_cur->bounce_buf = NULL;
 283
 284         kfree(mqrq_prev->sg);
 285         mqrq_prev->sg = NULL;
 286         kfree(mqrq_prev->bounce_buf);
 287         mqrq_prev->bounce_buf = NULL;
 288
 289         blk_cleanup_queue(mq->queue);
 290         return ret;
 291 }
 292
 293 void mmc_cleanup_queue(struct mmc_queue *mq)
 294 {
 295         struct request_queue *q = mq->queue;
 296         unsigned long flags;
 297         struct mmc_queue_req *mqrq_cur = mq->mqrq_cur;
 298         struct mmc_queue_req *mqrq_prev = mq->mqrq_prev;
 299
 300         /* Make sure the queue isn't suspended, as that will deadlock */
 301         mmc_queue_resume(mq);
 302
 303         /* Then terminate our worker thread */
 304         kthread_stop(mq->thread);
 305
 306         /* Empty the queue */
 307         spin_lock_irqsave(q->queue_lock, flags);
 308         q->queuedata = NULL;
 309         blk_start_queue(q);
 310         spin_unlock_irqrestore(q->queue_lock, flags);
 311
 312         kfree(mqrq_cur->bounce_sg);
 313         mqrq_cur->bounce_sg = NULL;
 314
 315         kfree(mqrq_cur->sg);
 316         mqrq_cur->sg = NULL;
 317
 318         kfree(mqrq_cur->bounce_buf);
 319         mqrq_cur->bounce_buf = NULL;
 320
 321         kfree(mqrq_prev->bounce_sg);
 322         mqrq_prev->bounce_sg = NULL;
 323
 324         kfree(mqrq_prev->sg);
 325         mqrq_prev->sg = NULL;
 326
 327         kfree(mqrq_prev->bounce_buf);
 328         mqrq_prev->bounce_buf = NULL;
 329
 330         mq->card = NULL;
 331 }
 332 EXPORT_SYMBOL(mmc_cleanup_queue);
 333
 334 /**
 335  * mmc_queue_suspend - suspend a MMC request queue
 336  * @mq: MMC queue to suspend
 337  *
 338  * Stop the block request queue, and wait for our thread to
 339  * complete any outstanding requests.  This ensures that we
 340  * won't suspend while a request is being processed.
 341  */
 342 void mmc_queue_suspend(struct mmc_queue *mq)
 343 {
 344         struct request_queue *q = mq->queue;
 345         unsigned long flags;
 346
 347         if (!(mq->flags & MMC_QUEUE_SUSPENDED)) {
 348                 mq->flags |= MMC_QUEUE_SUSPENDED;
 349
 350                 spin_lock_irqsave(q->queue_lock, flags);
 351                 blk_stop_queue(q);
 352                 spin_unlock_irqrestore(q->queue_lock, flags);
 353
 354                 down(&mq->thread_sem);
 355         }
 356 }
 357
 358 /**
 359  * mmc_queue_resume - resume a previously suspended MMC request queue
 360  * @mq: MMC queue to resume
 361  */
 362 void mmc_queue_resume(struct mmc_queue *mq)
 363 {
 364         struct request_queue *q = mq->queue;
 365         unsigned long flags;
 366
 367         if (mq->flags & MMC_QUEUE_SUSPENDED) {
 368                 mq->flags &= ~MMC_QUEUE_SUSPENDED;
 369
 370                 up(&mq->thread_sem);
 371
 372                 spin_lock_irqsave(q->queue_lock, flags);
 373                 blk_start_queue(q);
 374                 spin_unlock_irqrestore(q->queue_lock, flags);
 375         }
 376 }
 377
 378 /*
 379  * Prepare the sg list(s) to be handed of to the host driver
 380  */
 381 unsigned int mmc_queue_map_sg(struct mmc_queue *mq, struct mmc_queue_req *mqrq)
 382 {
 383         unsigned int sg_len;
 384         size_t buflen;
 385         struct scatterlist *sg;
 386         int i;
 387
 388         if (!mqrq->bounce_buf)
 389                 return blk_rq_map_sg(mq->queue, mqrq->req, mqrq->sg);
 390
 391         BUG_ON(!mqrq->bounce_sg);
 392
 393         sg_len = blk_rq_map_sg(mq->queue, mqrq->req, mqrq->bounce_sg);
 394
 395         mqrq->bounce_sg_len = sg_len;
 396
 397         buflen = 0;
 398         for_each_sg(mqrq->bounce_sg, sg, sg_len, i)
 399                 buflen += sg->length;
 400
 401         sg_init_one(mqrq->sg, mqrq->bounce_buf, buflen);
 402
 403         return 1;
 404 }
 405
 406 /*
 407  * If writing, bounce the data to the buffer before the request
 408  * is sent to the host driver
 409  */
 410 void mmc_queue_bounce_pre(struct mmc_queue_req *mqrq)
 411 {
 412         if (!mqrq->bounce_buf)
 413                 return;
 414
 415         if (rq_data_dir(mqrq->req) != WRITE)
 416                 return;
 417
 418         sg_copy_to_buffer(mqrq->bounce_sg, mqrq->bounce_sg_len,
 419                 mqrq->bounce_buf, mqrq->sg[0].length);
 420 }
 421
 422 /*
 423  * If reading, bounce the data from the buffer after the request
 424  * has been handled by the host driver
 425  */
 426 void mmc_queue_bounce_post(struct mmc_queue_req *mqrq)
 427 {
 428         if (!mqrq->bounce_buf)
 429                 return;
 430
 431         if (rq_data_dir(mqrq->req) != READ)
 432                 return;
 433
 434         sg_copy_from_buffer(mqrq->bounce_sg, mqrq->bounce_sg_len,
 435                 mqrq->bounce_buf, mqrq->sg[0].length);
 436 }