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