drivers/mmc/core/queue.c

   1 /*
   2  *  Copyright (C) 2003 Russell King, All Rights Reserved.
   3  *  Copyright 2006-2007 Pierre Ossman
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  */
  10 #include <linux/slab.h>
  11 #include <linux/module.h>
  12 #include <linux/blkdev.h>
  13 #include <linux/freezer.h>
  14 #include <linux/kthread.h>
  15 #include <linux/scatterlist.h>
  16 #include <linux/dma-mapping.h>
  17
  18 #include <linux/mmc/card.h>
  19 #include <linux/mmc/host.h>
  20
  21 #include "queue.h"
  22 #include "block.h"
  23
  24 #define MMC_QUEUE_BOUNCESZ      65536
  25
  26 /*
  27  * Prepare a MMC request. This just filters out odd stuff.
  28  */
  29 static int mmc_prep_request(struct request_queue *q, struct request *req)
  30 {
  31         struct mmc_queue *mq = q->queuedata;
  32
  33         /*
  34          * We only like normal block requests and discards.
  35          */
  36         if (req->cmd_type != REQ_TYPE_FS && req_op(req) != REQ_OP_DISCARD &&
  37             req_op(req) != REQ_OP_SECURE_ERASE) {
  38                 blk_dump_rq_flags(req, "MMC bad request");
  39                 return BLKPREP_KILL;
  40         }
  41
  42         if (mq && (mmc_card_removed(mq->card) || mmc_access_rpmb(mq)))
  43                 return BLKPREP_KILL;
  44
  45         req->rq_flags |= RQF_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         struct mmc_context_info *cntx = &mq->card->host->context_info;
  55
  56         current->flags |= PF_MEMALLOC;
  57
  58         down(&mq->thread_sem);
  59         do {
  60                 struct request *req = NULL;
  61
  62                 spin_lock_irq(q->queue_lock);
  63                 set_current_state(TASK_INTERRUPTIBLE);
  64                 req = blk_fetch_request(q);
  65                 mq->asleep = false;
  66                 cntx->is_waiting_last_req = false;
  67                 cntx->is_new_req = false;
  68                 if (!req) {
  69                         /*
  70                          * Dispatch queue is empty so set flags for
  71                          * mmc_request_fn() to wake us up.
  72                          */
  73                         if (mq->mqrq_prev->req)
  74                                 cntx->is_waiting_last_req = true;
  75                         else
  76                                 mq->asleep = true;
  77                 }
  78                 mq->mqrq_cur->req = req;
  79                 spin_unlock_irq(q->queue_lock);
  80
  81                 if (req || mq->mqrq_prev->req) {
  82                         bool req_is_special = mmc_req_is_special(req);
  83
  84                         set_current_state(TASK_RUNNING);
  85                         mmc_blk_issue_rq(mq, req);
  86                         cond_resched();
  87                         if (mq->flags & MMC_QUEUE_NEW_REQUEST) {
  88                                 mq->flags &= ~MMC_QUEUE_NEW_REQUEST;
  89                                 continue; /* fetch again */
  90                         }
  91
  92                         /*
  93                          * Current request becomes previous request
  94                          * and vice versa.
  95                          * In case of special requests, current request
  96                          * has been finished. Do not assign it to previous
  97                          * request.
  98                          */
  99                         if (req_is_special)
 100                                 mq->mqrq_cur->req = NULL;
 101
 102                         mq->mqrq_prev->brq.mrq.data = NULL;
 103                         mq->mqrq_prev->req = NULL;
 104                         swap(mq->mqrq_prev, mq->mqrq_cur);
 105                 } else {
 106                         if (kthread_should_stop()) {
 107                                 set_current_state(TASK_RUNNING);
 108                                 break;
 109                         }
 110                         up(&mq->thread_sem);
 111                         schedule();
 112                         down(&mq->thread_sem);
 113                 }
 114         } while (1);
 115         up(&mq->thread_sem);
 116
 117         return 0;
 118 }
 119
 120 /*
 121  * Generic MMC request handler.  This is called for any queue on a
 122  * particular host.  When the host is not busy, we look for a request
 123  * on any queue on this host, and attempt to issue it.  This may
 124  * not be the queue we were asked to process.
 125  */
 126 static void mmc_request_fn(struct request_queue *q)
 127 {
 128         struct mmc_queue *mq = q->queuedata;
 129         struct request *req;
 130         struct mmc_context_info *cntx;
 131
 132         if (!mq) {
 133                 while ((req = blk_fetch_request(q)) != NULL) {
 134                         req->rq_flags |= RQF_QUIET;
 135                         __blk_end_request_all(req, -EIO);
 136                 }
 137                 return;
 138         }
 139
 140         cntx = &mq->card->host->context_info;
 141
 142         if (cntx->is_waiting_last_req) {
 143                 cntx->is_new_req = true;
 144                 wake_up_interruptible(&cntx->wait);
 145         }
 146
 147         if (mq->asleep)
 148                 wake_up_process(mq->thread);
 149 }
 150
 151 static struct scatterlist *mmc_alloc_sg(int sg_len, int *err)
 152 {
 153         struct scatterlist *sg;
 154
 155         sg = kmalloc(sizeof(struct scatterlist)*sg_len, GFP_KERNEL);
 156         if (!sg)
 157                 *err = -ENOMEM;
 158         else {
 159                 *err = 0;
 160                 sg_init_table(sg, sg_len);
 161         }
 162
 163         return sg;
 164 }
 165
 166 static void mmc_queue_setup_discard(struct request_queue *q,
 167                                     struct mmc_card *card)
 168 {
 169         unsigned max_discard;
 170
 171         max_discard = mmc_calc_max_discard(card);
 172         if (!max_discard)
 173                 return;
 174
 175         queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
 176         blk_queue_max_discard_sectors(q, max_discard);
 177         if (card->erased_byte == 0 && !mmc_can_discard(card))
 178                 q->limits.discard_zeroes_data = 1;
 179         q->limits.discard_granularity = card->pref_erase << 9;
 180         /* granularity must not be greater than max. discard */
 181         if (card->pref_erase > max_discard)
 182                 q->limits.discard_granularity = 0;
 183         if (mmc_can_secure_erase_trim(card))
 184                 queue_flag_set_unlocked(QUEUE_FLAG_SECERASE, q);
 185 }
 186
 187 #ifdef CONFIG_MMC_BLOCK_BOUNCE
 188 static bool mmc_queue_alloc_bounce_bufs(struct mmc_queue *mq,
 189                                         unsigned int bouncesz)
 190 {
 191         int i;
 192
 193         for (i = 0; i < mq->qdepth; i++) {
 194                 mq->mqrq[i].bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
 195                 if (!mq->mqrq[i].bounce_buf)
 196                         goto out_err;
 197         }
 198
 199         return true;
 200
 201 out_err:
 202         while (--i >= 0) {
 203                 kfree(mq->mqrq[i].bounce_buf);
 204                 mq->mqrq[i].bounce_buf = NULL;
 205         }
 206         pr_warn("%s: unable to allocate bounce buffers\n",
 207                 mmc_card_name(mq->card));
 208         return false;
 209 }
 210
 211 static int mmc_queue_alloc_bounce_sgs(struct mmc_queue *mq,
 212                                       unsigned int bouncesz)
 213 {
 214         int i, ret;
 215
 216         for (i = 0; i < mq->qdepth; i++) {
 217                 mq->mqrq[i].sg = mmc_alloc_sg(1, &ret);
 218                 if (ret)
 219                         return ret;
 220
 221                 mq->mqrq[i].bounce_sg = mmc_alloc_sg(bouncesz / 512, &ret);
 222                 if (ret)
 223                         return ret;
 224         }
 225
 226         return 0;
 227 }
 228 #endif
 229
 230 static int mmc_queue_alloc_sgs(struct mmc_queue *mq, int max_segs)
 231 {
 232         int i, ret;
 233
 234         for (i = 0; i < mq->qdepth; i++) {
 235                 mq->mqrq[i].sg = mmc_alloc_sg(max_segs, &ret);
 236                 if (ret)
 237                         return ret;
 238         }
 239
 240         return 0;
 241 }
 242
 243 static void mmc_queue_req_free_bufs(struct mmc_queue_req *mqrq)
 244 {
 245         kfree(mqrq->bounce_sg);
 246         mqrq->bounce_sg = NULL;
 247
 248         kfree(mqrq->sg);
 249         mqrq->sg = NULL;
 250
 251         kfree(mqrq->bounce_buf);
 252         mqrq->bounce_buf = NULL;
 253 }
 254
 255 static void mmc_queue_reqs_free_bufs(struct mmc_queue *mq)
 256 {
 257         int i;
 258
 259         for (i = 0; i < mq->qdepth; i++)
 260                 mmc_queue_req_free_bufs(&mq->mqrq[i]);
 261 }
 262
 263 /**
 264  * mmc_init_queue - initialise a queue structure.
 265  * @mq: mmc queue
 266  * @card: mmc card to attach this queue
 267  * @lock: queue lock
 268  * @subname: partition subname
 269  *
 270  * Initialise a MMC card request queue.
 271  */
 272 int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card,
 273                    spinlock_t *lock, const char *subname)
 274 {
 275         struct mmc_host *host = card->host;
 276         u64 limit = BLK_BOUNCE_HIGH;
 277         bool bounce = false;
 278         int ret = -ENOMEM;
 279
 280         if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
 281                 limit = (u64)dma_max_pfn(mmc_dev(host)) << PAGE_SHIFT;
 282
 283         mq->card = card;
 284         mq->queue = blk_init_queue(mmc_request_fn, lock);
 285         if (!mq->queue)
 286                 return -ENOMEM;
 287
 288         mq->qdepth = 2;
 289         mq->mqrq = kcalloc(mq->qdepth, sizeof(struct mmc_queue_req),
 290                            GFP_KERNEL);
 291         if (!mq->mqrq)
 292                 goto blk_cleanup;
 293         mq->mqrq_cur = &mq->mqrq[0];
 294         mq->mqrq_prev = &mq->mqrq[1];
 295         mq->queue->queuedata = mq;
 296
 297         blk_queue_prep_rq(mq->queue, mmc_prep_request);
 298         queue_flag_set_unlocked(QUEUE_FLAG_NONROT, mq->queue);
 299         queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, mq->queue);
 300         if (mmc_can_erase(card))
 301                 mmc_queue_setup_discard(mq->queue, card);
 302
 303 #ifdef CONFIG_MMC_BLOCK_BOUNCE
 304         if (host->max_segs == 1) {
 305                 unsigned int bouncesz;
 306
 307                 bouncesz = MMC_QUEUE_BOUNCESZ;
 308
 309                 if (bouncesz > host->max_req_size)
 310                         bouncesz = host->max_req_size;
 311                 if (bouncesz > host->max_seg_size)
 312                         bouncesz = host->max_seg_size;
 313                 if (bouncesz > (host->max_blk_count * 512))
 314                         bouncesz = host->max_blk_count * 512;
 315
 316                 if (bouncesz > 512 &&
 317                     mmc_queue_alloc_bounce_bufs(mq, bouncesz)) {
 318                         blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_ANY);
 319                         blk_queue_max_hw_sectors(mq->queue, bouncesz / 512);
 320                         blk_queue_max_segments(mq->queue, bouncesz / 512);
 321                         blk_queue_max_segment_size(mq->queue, bouncesz);
 322
 323                         ret = mmc_queue_alloc_bounce_sgs(mq, bouncesz);
 324                         if (ret)
 325                                 goto cleanup_queue;
 326                         bounce = true;
 327                 }
 328         }
 329 #endif
 330
 331         if (!bounce) {
 332                 blk_queue_bounce_limit(mq->queue, limit);
 333                 blk_queue_max_hw_sectors(mq->queue,
 334                         min(host->max_blk_count, host->max_req_size / 512));
 335                 blk_queue_max_segments(mq->queue, host->max_segs);
 336                 blk_queue_max_segment_size(mq->queue, host->max_seg_size);
 337
 338                 ret = mmc_queue_alloc_sgs(mq, host->max_segs);
 339                 if (ret)
 340                         goto cleanup_queue;
 341         }
 342
 343         sema_init(&mq->thread_sem, 1);
 344
 345         mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd/%d%s",
 346                 host->index, subname ? subname : "");
 347
 348         if (IS_ERR(mq->thread)) {
 349                 ret = PTR_ERR(mq->thread);
 350                 goto cleanup_queue;
 351         }
 352
 353         return 0;
 354
 355  cleanup_queue:
 356         mmc_queue_reqs_free_bufs(mq);
 357         kfree(mq->mqrq);
 358         mq->mqrq = NULL;
 359 blk_cleanup:
 360         blk_cleanup_queue(mq->queue);
 361         return ret;
 362 }
 363
 364 void mmc_cleanup_queue(struct mmc_queue *mq)
 365 {
 366         struct request_queue *q = mq->queue;
 367         unsigned long flags;
 368
 369         /* Make sure the queue isn't suspended, as that will deadlock */
 370         mmc_queue_resume(mq);
 371
 372         /* Then terminate our worker thread */
 373         kthread_stop(mq->thread);
 374
 375         /* Empty the queue */
 376         spin_lock_irqsave(q->queue_lock, flags);
 377         q->queuedata = NULL;
 378         blk_start_queue(q);
 379         spin_unlock_irqrestore(q->queue_lock, flags);
 380
 381         mmc_queue_reqs_free_bufs(mq);
 382         kfree(mq->mqrq);
 383         mq->mqrq = NULL;
 384
 385         mq->card = NULL;
 386 }
 387 EXPORT_SYMBOL(mmc_cleanup_queue);
 388
 389 /**
 390  * mmc_queue_suspend - suspend a MMC request queue
 391  * @mq: MMC queue to suspend
 392  *
 393  * Stop the block request queue, and wait for our thread to
 394  * complete any outstanding requests.  This ensures that we
 395  * won't suspend while a request is being processed.
 396  */
 397 void mmc_queue_suspend(struct mmc_queue *mq)
 398 {
 399         struct request_queue *q = mq->queue;
 400         unsigned long flags;
 401
 402         if (!(mq->flags & MMC_QUEUE_SUSPENDED)) {
 403                 mq->flags |= MMC_QUEUE_SUSPENDED;
 404
 405                 spin_lock_irqsave(q->queue_lock, flags);
 406                 blk_stop_queue(q);
 407                 spin_unlock_irqrestore(q->queue_lock, flags);
 408
 409                 down(&mq->thread_sem);
 410         }
 411 }
 412
 413 /**
 414  * mmc_queue_resume - resume a previously suspended MMC request queue
 415  * @mq: MMC queue to resume
 416  */
 417 void mmc_queue_resume(struct mmc_queue *mq)
 418 {
 419         struct request_queue *q = mq->queue;
 420         unsigned long flags;
 421
 422         if (mq->flags & MMC_QUEUE_SUSPENDED) {
 423                 mq->flags &= ~MMC_QUEUE_SUSPENDED;
 424
 425                 up(&mq->thread_sem);
 426
 427                 spin_lock_irqsave(q->queue_lock, flags);
 428                 blk_start_queue(q);
 429                 spin_unlock_irqrestore(q->queue_lock, flags);
 430         }
 431 }
 432
 433 /*
 434  * Prepare the sg list(s) to be handed of to the host driver
 435  */
 436 unsigned int mmc_queue_map_sg(struct mmc_queue *mq, struct mmc_queue_req *mqrq)
 437 {
 438         unsigned int sg_len;
 439         size_t buflen;
 440         struct scatterlist *sg;
 441         int i;
 442
 443         if (!mqrq->bounce_buf)
 444                 return blk_rq_map_sg(mq->queue, mqrq->req, mqrq->sg);
 445
 446         sg_len = blk_rq_map_sg(mq->queue, mqrq->req, mqrq->bounce_sg);
 447
 448         mqrq->bounce_sg_len = sg_len;
 449
 450         buflen = 0;
 451         for_each_sg(mqrq->bounce_sg, sg, sg_len, i)
 452                 buflen += sg->length;
 453
 454         sg_init_one(mqrq->sg, mqrq->bounce_buf, buflen);
 455
 456         return 1;
 457 }
 458
 459 /*
 460  * If writing, bounce the data to the buffer before the request
 461  * is sent to the host driver
 462  */
 463 void mmc_queue_bounce_pre(struct mmc_queue_req *mqrq)
 464 {
 465         if (!mqrq->bounce_buf)
 466                 return;
 467
 468         if (rq_data_dir(mqrq->req) != WRITE)
 469                 return;
 470
 471         sg_copy_to_buffer(mqrq->bounce_sg, mqrq->bounce_sg_len,
 472                 mqrq->bounce_buf, mqrq->sg[0].length);
 473 }
 474
 475 /*
 476  * If reading, bounce the data from the buffer after the request
 477  * has been handled by the host driver
 478  */
 479 void mmc_queue_bounce_post(struct mmc_queue_req *mqrq)
 480 {
 481         if (!mqrq->bounce_buf)
 482                 return;
 483
 484         if (rq_data_dir(mqrq->req) != READ)
 485                 return;
 486
 487         sg_copy_from_buffer(mqrq->bounce_sg, mqrq->bounce_sg_len,
 488                 mqrq->bounce_buf, mqrq->sg[0].length);
 489 }