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