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 #define MMC_REQ_SPECIAL_MASK    (REQ_DISCARD | REQ_FLUSH)
  28
  29 /*
  30  * Prepare a MMC request. This just filters out odd stuff.
  31  */
  32 static int mmc_prep_request(struct request_queue *q, struct request *req)
  33 {
  34         struct mmc_queue *mq = q->queuedata;
  35
  36         /*
  37          * We only like normal block requests and discards.
  38          */
  39         if (req->cmd_type != REQ_TYPE_FS && !(req->cmd_flags & REQ_DISCARD)) {
  40                 blk_dump_rq_flags(req, "MMC bad request");
  41                 return BLKPREP_KILL;
  42         }
  43
  44         if (mq && mmc_card_removed(mq->card))
  45                 return BLKPREP_KILL;
  46
  47         req->cmd_flags |= REQ_DONTPREP;
  48
  49         return BLKPREP_OK;
  50 }
  51
  52 static int mmc_queue_thread(void *d)
  53 {
  54         struct mmc_queue *mq = d;
  55         struct request_queue *q = mq->queue;
  56
  57         current->flags |= PF_MEMALLOC;
  58
  59         down(&mq->thread_sem);
  60         do {
  61                 struct request *req = NULL;
  62                 struct mmc_queue_req *tmp;
  63                 unsigned int cmd_flags = 0;
  64
  65                 spin_lock_irq(q->queue_lock);
  66                 set_current_state(TASK_INTERRUPTIBLE);
  67                 req = blk_fetch_request(q);
  68                 mq->mqrq_cur->req = req;
  69                 spin_unlock_irq(q->queue_lock);
  70
  71                 if (req || mq->mqrq_prev->req) {
  72                         set_current_state(TASK_RUNNING);
  73                         cmd_flags = req ? req->cmd_flags : 0;
  74                         mq->issue_fn(mq, req);
  75
  76                         /*
  77                          * Current request becomes previous request
  78                          * and vice versa.
  79                          * In case of special requests, current request
  80                          * has been finished. Do not assign it to previous
  81                          * request.
  82                          */
  83                         if (cmd_flags & MMC_REQ_SPECIAL_MASK)
  84                                 mq->mqrq_cur->req = NULL;
  85
  86                         mq->mqrq_prev->brq.mrq.data = NULL;
  87                         mq->mqrq_prev->req = NULL;
  88                         tmp = mq->mqrq_prev;
  89                         mq->mqrq_prev = mq->mqrq_cur;
  90                         mq->mqrq_cur = tmp;
  91                 } else {
  92                         if (kthread_should_stop()) {
  93                                 set_current_state(TASK_RUNNING);
  94                                 break;
  95                         }
  96                         up(&mq->thread_sem);
  97                         schedule();
  98                         down(&mq->thread_sem);
  99                 }
 100         } while (1);
 101         up(&mq->thread_sem);
 102
 103         return 0;
 104 }
 105
 106 /*
 107  * Generic MMC request handler.  This is called for any queue on a
 108  * particular host.  When the host is not busy, we look for a request
 109  * on any queue on this host, and attempt to issue it.  This may
 110  * not be the queue we were asked to process.
 111  */
 112 static void mmc_request_fn(struct request_queue *q)
 113 {
 114         struct mmc_queue *mq = q->queuedata;
 115         struct request *req;
 116
 117         if (!mq) {
 118                 while ((req = blk_fetch_request(q)) != NULL) {
 119                         req->cmd_flags |= REQ_QUIET;
 120                         __blk_end_request_all(req, -EIO);
 121                 }
 122                 return;
 123         }
 124
 125         if (!mq->mqrq_cur->req && !mq->mqrq_prev->req)
 126                 wake_up_process(mq->thread);
 127 }
 128
 129 static struct scatterlist *mmc_alloc_sg(int sg_len, int *err)
 130 {
 131         struct scatterlist *sg;
 132
 133         sg = kmalloc(sizeof(struct scatterlist)*sg_len, GFP_KERNEL);
 134         if (!sg)
 135                 *err = -ENOMEM;
 136         else {
 137                 *err = 0;
 138                 sg_init_table(sg, sg_len);
 139         }
 140
 141         return sg;
 142 }
 143
 144 static void mmc_queue_setup_discard(struct request_queue *q,
 145                                     struct mmc_card *card)
 146 {
 147         unsigned max_discard;
 148
 149         max_discard = mmc_calc_max_discard(card);
 150         if (!max_discard)
 151                 return;
 152
 153         queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
 154         q->limits.max_discard_sectors = max_discard;
 155         if (card->erased_byte == 0 && !mmc_can_discard(card))
 156                 q->limits.discard_zeroes_data = 1;
 157         q->limits.discard_granularity = card->pref_erase << 9;
 158         /* granularity must not be greater than max. discard */
 159         if (card->pref_erase > max_discard)
 160                 q->limits.discard_granularity = 0;
 161         if (mmc_can_secure_erase_trim(card) || mmc_can_sanitize(card))
 162                 queue_flag_set_unlocked(QUEUE_FLAG_SECDISCARD, q);
 163 }
 164
 165 /**
 166  * mmc_init_queue - initialise a queue structure.
 167  * @mq: mmc queue
 168  * @card: mmc card to attach this queue
 169  * @lock: queue lock
 170  * @subname: partition subname
 171  *
 172  * Initialise a MMC card request queue.
 173  */
 174 int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card,
 175                    spinlock_t *lock, const char *subname)
 176 {
 177         struct mmc_host *host = card->host;
 178         u64 limit = BLK_BOUNCE_HIGH;
 179         int ret;
 180         struct mmc_queue_req *mqrq_cur = &mq->mqrq[0];
 181         struct mmc_queue_req *mqrq_prev = &mq->mqrq[1];
 182
 183         if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
 184                 limit = *mmc_dev(host)->dma_mask;
 185
 186         mq->card = card;
 187         mq->queue = blk_init_queue(mmc_request_fn, lock);
 188         if (!mq->queue)
 189                 return -ENOMEM;
 190
 191         mq->mqrq_cur = mqrq_cur;
 192         mq->mqrq_prev = mqrq_prev;
 193         mq->queue->queuedata = mq;
 194
 195         blk_queue_prep_rq(mq->queue, mmc_prep_request);
 196         queue_flag_set_unlocked(QUEUE_FLAG_NONROT, mq->queue);
 197         if (mmc_can_erase(card))
 198                 mmc_queue_setup_discard(mq->queue, card);
 199
 200 #ifdef CONFIG_MMC_BLOCK_BOUNCE
 201         if (host->max_segs == 1) {
 202                 unsigned int bouncesz;
 203
 204                 bouncesz = MMC_QUEUE_BOUNCESZ;
 205
 206                 if (bouncesz > host->max_req_size)
 207                         bouncesz = host->max_req_size;
 208                 if (bouncesz > host->max_seg_size)
 209                         bouncesz = host->max_seg_size;
 210                 if (bouncesz > (host->max_blk_count * 512))
 211                         bouncesz = host->max_blk_count * 512;
 212
 213                 if (bouncesz > 512) {
 214                         mqrq_cur->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
 215                         if (!mqrq_cur->bounce_buf) {
 216                                 pr_warning("%s: unable to "
 217                                         "allocate bounce cur buffer\n",
 218                                         mmc_card_name(card));
 219                         }
 220                         mqrq_prev->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
 221                         if (!mqrq_prev->bounce_buf) {
 222                                 pr_warning("%s: unable to "
 223                                         "allocate bounce prev buffer\n",
 224                                         mmc_card_name(card));
 225                                 kfree(mqrq_cur->bounce_buf);
 226                                 mqrq_cur->bounce_buf = NULL;
 227                         }
 228                 }
 229
 230                 if (mqrq_cur->bounce_buf && mqrq_prev->bounce_buf) {
 231                         blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_ANY);
 232                         blk_queue_max_hw_sectors(mq->queue, bouncesz / 512);
 233                         blk_queue_max_segments(mq->queue, bouncesz / 512);
 234                         blk_queue_max_segment_size(mq->queue, bouncesz);
 235
 236                         mqrq_cur->sg = mmc_alloc_sg(1, &ret);
 237                         if (ret)
 238                                 goto cleanup_queue;
 239
 240                         mqrq_cur->bounce_sg =
 241                                 mmc_alloc_sg(bouncesz / 512, &ret);
 242                         if (ret)
 243                                 goto cleanup_queue;
 244
 245                         mqrq_prev->sg = mmc_alloc_sg(1, &ret);
 246                         if (ret)
 247                                 goto cleanup_queue;
 248
 249                         mqrq_prev->bounce_sg =
 250                                 mmc_alloc_sg(bouncesz / 512, &ret);
 251                         if (ret)
 252                                 goto cleanup_queue;
 253                 }
 254         }
 255 #endif
 256
 257         if (!mqrq_cur->bounce_buf && !mqrq_prev->bounce_buf) {
 258                 blk_queue_bounce_limit(mq->queue, limit);
 259                 blk_queue_max_hw_sectors(mq->queue,
 260                         min(host->max_blk_count, host->max_req_size / 512));
 261                 blk_queue_max_segments(mq->queue, host->max_segs);
 262                 blk_queue_max_segment_size(mq->queue, host->max_seg_size);
 263
 264                 mqrq_cur->sg = mmc_alloc_sg(host->max_segs, &ret);
 265                 if (ret)
 266                         goto cleanup_queue;
 267
 268
 269                 mqrq_prev->sg = mmc_alloc_sg(host->max_segs, &ret);
 270                 if (ret)
 271                         goto cleanup_queue;
 272         }
 273
 274         sema_init(&mq->thread_sem, 1);
 275
 276         mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd/%d%s",
 277                 host->index, subname ? subname : "");
 278
 279         if (IS_ERR(mq->thread)) {
 280                 ret = PTR_ERR(mq->thread);
 281                 goto free_bounce_sg;
 282         }
 283
 284         return 0;
 285  free_bounce_sg:
 286         kfree(mqrq_cur->bounce_sg);
 287         mqrq_cur->bounce_sg = NULL;
 288         kfree(mqrq_prev->bounce_sg);
 289         mqrq_prev->bounce_sg = NULL;
 290
 291  cleanup_queue:
 292         kfree(mqrq_cur->sg);
 293         mqrq_cur->sg = NULL;
 294         kfree(mqrq_cur->bounce_buf);
 295         mqrq_cur->bounce_buf = NULL;
 296
 297         kfree(mqrq_prev->sg);
 298         mqrq_prev->sg = NULL;
 299         kfree(mqrq_prev->bounce_buf);
 300         mqrq_prev->bounce_buf = NULL;
 301
 302         blk_cleanup_queue(mq->queue);
 303         return ret;
 304 }
 305
 306 void mmc_cleanup_queue(struct mmc_queue *mq)
 307 {
 308         struct request_queue *q = mq->queue;
 309         unsigned long flags;
 310         struct mmc_queue_req *mqrq_cur = mq->mqrq_cur;
 311         struct mmc_queue_req *mqrq_prev = mq->mqrq_prev;
 312
 313         /* Make sure the queue isn't suspended, as that will deadlock */
 314         mmc_queue_resume(mq);
 315
 316         /* Then terminate our worker thread */
 317         kthread_stop(mq->thread);
 318
 319         /* Empty the queue */
 320         spin_lock_irqsave(q->queue_lock, flags);
 321         q->queuedata = NULL;
 322         blk_start_queue(q);
 323         spin_unlock_irqrestore(q->queue_lock, flags);
 324
 325         kfree(mqrq_cur->bounce_sg);
 326         mqrq_cur->bounce_sg = NULL;
 327
 328         kfree(mqrq_cur->sg);
 329         mqrq_cur->sg = NULL;
 330
 331         kfree(mqrq_cur->bounce_buf);
 332         mqrq_cur->bounce_buf = NULL;
 333
 334         kfree(mqrq_prev->bounce_sg);
 335         mqrq_prev->bounce_sg = NULL;
 336
 337         kfree(mqrq_prev->sg);
 338         mqrq_prev->sg = NULL;
 339
 340         kfree(mqrq_prev->bounce_buf);
 341         mqrq_prev->bounce_buf = NULL;
 342
 343         mq->card = NULL;
 344 }
 345 EXPORT_SYMBOL(mmc_cleanup_queue);
 346
 347 /**
 348  * mmc_queue_suspend - suspend a MMC request queue
 349  * @mq: MMC queue to suspend
 350  *
 351  * Stop the block request queue, and wait for our thread to
 352  * complete any outstanding requests.  This ensures that we
 353  * won't suspend while a request is being processed.
 354  */
 355 void mmc_queue_suspend(struct mmc_queue *mq)
 356 {
 357         struct request_queue *q = mq->queue;
 358         unsigned long flags;
 359
 360         if (!(mq->flags & MMC_QUEUE_SUSPENDED)) {
 361                 mq->flags |= MMC_QUEUE_SUSPENDED;
 362
 363                 spin_lock_irqsave(q->queue_lock, flags);
 364                 blk_stop_queue(q);
 365                 spin_unlock_irqrestore(q->queue_lock, flags);
 366
 367                 down(&mq->thread_sem);
 368         }
 369 }
 370
 371 /**
 372  * mmc_queue_resume - resume a previously suspended MMC request queue
 373  * @mq: MMC queue to resume
 374  */
 375 void mmc_queue_resume(struct mmc_queue *mq)
 376 {
 377         struct request_queue *q = mq->queue;
 378         unsigned long flags;
 379
 380         if (mq->flags & MMC_QUEUE_SUSPENDED) {
 381                 mq->flags &= ~MMC_QUEUE_SUSPENDED;
 382
 383                 up(&mq->thread_sem);
 384
 385                 spin_lock_irqsave(q->queue_lock, flags);
 386                 blk_start_queue(q);
 387                 spin_unlock_irqrestore(q->queue_lock, flags);
 388         }
 389 }
 390
 391 /*
 392  * Prepare the sg list(s) to be handed of to the host driver
 393  */
 394 unsigned int mmc_queue_map_sg(struct mmc_queue *mq, struct mmc_queue_req *mqrq)
 395 {
 396         unsigned int sg_len;
 397         size_t buflen;
 398         struct scatterlist *sg;
 399         int i;
 400
 401         if (!mqrq->bounce_buf)
 402                 return blk_rq_map_sg(mq->queue, mqrq->req, mqrq->sg);
 403
 404         BUG_ON(!mqrq->bounce_sg);
 405
 406         sg_len = blk_rq_map_sg(mq->queue, mqrq->req, mqrq->bounce_sg);
 407
 408         mqrq->bounce_sg_len = sg_len;
 409
 410         buflen = 0;
 411         for_each_sg(mqrq->bounce_sg, sg, sg_len, i)
 412                 buflen += sg->length;
 413
 414         sg_init_one(mqrq->sg, mqrq->bounce_buf, buflen);
 415
 416         return 1;
 417 }
 418
 419 /*
 420  * If writing, bounce the data to the buffer before the request
 421  * is sent to the host driver
 422  */
 423 void mmc_queue_bounce_pre(struct mmc_queue_req *mqrq)
 424 {
 425         if (!mqrq->bounce_buf)
 426                 return;
 427
 428         if (rq_data_dir(mqrq->req) != WRITE)
 429                 return;
 430
 431         sg_copy_to_buffer(mqrq->bounce_sg, mqrq->bounce_sg_len,
 432                 mqrq->bounce_buf, mqrq->sg[0].length);
 433 }
 434
 435 /*
 436  * If reading, bounce the data from the buffer after the request
 437  * has been handled by the host driver
 438  */
 439 void mmc_queue_bounce_post(struct mmc_queue_req *mqrq)
 440 {
 441         if (!mqrq->bounce_buf)
 442                 return;
 443
 444         if (rq_data_dir(mqrq->req) != READ)
 445                 return;
 446
 447         sg_copy_from_buffer(mqrq->bounce_sg, mqrq->bounce_sg_len,
 448                 mqrq->bounce_buf, mqrq->sg[0].length);
 449 }