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 #include "core.h"
  24 #include "card.h"
  25
  26 #define MMC_QUEUE_BOUNCESZ      65536
  27
  28 /*
  29  * Prepare a MMC request. This just filters out odd stuff.
  30  */
  31 static int mmc_prep_request(struct request_queue *q, struct request *req)
  32 {
  33         struct mmc_queue *mq = q->queuedata;
  34
  35         if (mq && (mmc_card_removed(mq->card) || mmc_access_rpmb(mq)))
  36                 return BLKPREP_KILL;
  37
  38         req->rq_flags |= RQF_DONTPREP;
  39
  40         return BLKPREP_OK;
  41 }
  42
  43 static int mmc_queue_thread(void *d)
  44 {
  45         struct mmc_queue *mq = d;
  46         struct request_queue *q = mq->queue;
  47         struct mmc_context_info *cntx = &mq->card->host->context_info;
  48
  49         current->flags |= PF_MEMALLOC;
  50
  51         down(&mq->thread_sem);
  52         do {
  53                 struct request *req = NULL;
  54
  55                 spin_lock_irq(q->queue_lock);
  56                 set_current_state(TASK_INTERRUPTIBLE);
  57                 req = blk_fetch_request(q);
  58                 mq->asleep = false;
  59                 cntx->is_waiting_last_req = false;
  60                 cntx->is_new_req = false;
  61                 if (!req) {
  62                         /*
  63                          * Dispatch queue is empty so set flags for
  64                          * mmc_request_fn() to wake us up.
  65                          */
  66                         if (mq->mqrq_prev->req)
  67                                 cntx->is_waiting_last_req = true;
  68                         else
  69                                 mq->asleep = true;
  70                 }
  71                 mq->mqrq_cur->req = req;
  72                 spin_unlock_irq(q->queue_lock);
  73
  74                 if (req || mq->mqrq_prev->req) {
  75                         bool req_is_special = mmc_req_is_special(req);
  76
  77                         set_current_state(TASK_RUNNING);
  78                         mmc_blk_issue_rq(mq, req);
  79                         cond_resched();
  80                         if (mq->new_request) {
  81                                 mq->new_request = false;
  82                                 continue; /* fetch again */
  83                         }
  84
  85                         /*
  86                          * Current request becomes previous request
  87                          * and vice versa.
  88                          * In case of special requests, current request
  89                          * has been finished. Do not assign it to previous
  90                          * request.
  91                          */
  92                         if (req_is_special)
  93                                 mq->mqrq_cur->req = NULL;
  94
  95                         mq->mqrq_prev->brq.mrq.data = NULL;
  96                         mq->mqrq_prev->req = NULL;
  97                         swap(mq->mqrq_prev, mq->mqrq_cur);
  98                 } else {
  99                         if (kthread_should_stop()) {
 100                                 set_current_state(TASK_RUNNING);
 101                                 break;
 102                         }
 103                         up(&mq->thread_sem);
 104                         schedule();
 105                         down(&mq->thread_sem);
 106                 }
 107         } while (1);
 108         up(&mq->thread_sem);
 109
 110         return 0;
 111 }
 112
 113 /*
 114  * Generic MMC request handler.  This is called for any queue on a
 115  * particular host.  When the host is not busy, we look for a request
 116  * on any queue on this host, and attempt to issue it.  This may
 117  * not be the queue we were asked to process.
 118  */
 119 static void mmc_request_fn(struct request_queue *q)
 120 {
 121         struct mmc_queue *mq = q->queuedata;
 122         struct request *req;
 123         struct mmc_context_info *cntx;
 124
 125         if (!mq) {
 126                 while ((req = blk_fetch_request(q)) != NULL) {
 127                         req->rq_flags |= RQF_QUIET;
 128                         __blk_end_request_all(req, -EIO);
 129                 }
 130                 return;
 131         }
 132
 133         cntx = &mq->card->host->context_info;
 134
 135         if (cntx->is_waiting_last_req) {
 136                 cntx->is_new_req = true;
 137                 wake_up_interruptible(&cntx->wait);
 138         }
 139
 140         if (mq->asleep)
 141                 wake_up_process(mq->thread);
 142 }
 143
 144 static struct scatterlist *mmc_alloc_sg(int sg_len, int *err)
 145 {
 146         struct scatterlist *sg;
 147
 148         sg = kmalloc_array(sg_len, sizeof(*sg), GFP_KERNEL);
 149         if (!sg)
 150                 *err = -ENOMEM;
 151         else {
 152                 *err = 0;
 153                 sg_init_table(sg, sg_len);
 154         }
 155
 156         return sg;
 157 }
 158
 159 static void mmc_queue_setup_discard(struct request_queue *q,
 160                                     struct mmc_card *card)
 161 {
 162         unsigned max_discard;
 163
 164         max_discard = mmc_calc_max_discard(card);
 165         if (!max_discard)
 166                 return;
 167
 168         queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
 169         blk_queue_max_discard_sectors(q, max_discard);
 170         if (card->erased_byte == 0 && !mmc_can_discard(card))
 171                 q->limits.discard_zeroes_data = 1;
 172         q->limits.discard_granularity = card->pref_erase << 9;
 173         /* granularity must not be greater than max. discard */
 174         if (card->pref_erase > max_discard)
 175                 q->limits.discard_granularity = 0;
 176         if (mmc_can_secure_erase_trim(card))
 177                 queue_flag_set_unlocked(QUEUE_FLAG_SECERASE, q);
 178 }
 179
 180 #ifdef CONFIG_MMC_BLOCK_BOUNCE
 181 static bool mmc_queue_alloc_bounce_bufs(struct mmc_queue *mq,
 182                                         unsigned int bouncesz)
 183 {
 184         int i;
 185
 186         for (i = 0; i < mq->qdepth; i++) {
 187                 mq->mqrq[i].bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
 188                 if (!mq->mqrq[i].bounce_buf)
 189                         goto out_err;
 190         }
 191
 192         return true;
 193
 194 out_err:
 195         while (--i >= 0) {
 196                 kfree(mq->mqrq[i].bounce_buf);
 197                 mq->mqrq[i].bounce_buf = NULL;
 198         }
 199         pr_warn("%s: unable to allocate bounce buffers\n",
 200                 mmc_card_name(mq->card));
 201         return false;
 202 }
 203
 204 static int mmc_queue_alloc_bounce_sgs(struct mmc_queue *mq,
 205                                       unsigned int bouncesz)
 206 {
 207         int i, ret;
 208
 209         for (i = 0; i < mq->qdepth; i++) {
 210                 mq->mqrq[i].sg = mmc_alloc_sg(1, &ret);
 211                 if (ret)
 212                         return ret;
 213
 214                 mq->mqrq[i].bounce_sg = mmc_alloc_sg(bouncesz / 512, &ret);
 215                 if (ret)
 216                         return ret;
 217         }
 218
 219         return 0;
 220 }
 221 #endif
 222
 223 static int mmc_queue_alloc_sgs(struct mmc_queue *mq, int max_segs)
 224 {
 225         int i, ret;
 226
 227         for (i = 0; i < mq->qdepth; i++) {
 228                 mq->mqrq[i].sg = mmc_alloc_sg(max_segs, &ret);
 229                 if (ret)
 230                         return ret;
 231         }
 232
 233         return 0;
 234 }
 235
 236 static void mmc_queue_req_free_bufs(struct mmc_queue_req *mqrq)
 237 {
 238         kfree(mqrq->bounce_sg);
 239         mqrq->bounce_sg = NULL;
 240
 241         kfree(mqrq->sg);
 242         mqrq->sg = NULL;
 243
 244         kfree(mqrq->bounce_buf);
 245         mqrq->bounce_buf = NULL;
 246 }
 247
 248 static void mmc_queue_reqs_free_bufs(struct mmc_queue *mq)
 249 {
 250         int i;
 251
 252         for (i = 0; i < mq->qdepth; i++)
 253                 mmc_queue_req_free_bufs(&mq->mqrq[i]);
 254 }
 255
 256 /**
 257  * mmc_init_queue - initialise a queue structure.
 258  * @mq: mmc queue
 259  * @card: mmc card to attach this queue
 260  * @lock: queue lock
 261  * @subname: partition subname
 262  *
 263  * Initialise a MMC card request queue.
 264  */
 265 int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card,
 266                    spinlock_t *lock, const char *subname)
 267 {
 268         struct mmc_host *host = card->host;
 269         u64 limit = BLK_BOUNCE_HIGH;
 270         bool bounce = false;
 271         int ret = -ENOMEM;
 272
 273         if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
 274                 limit = (u64)dma_max_pfn(mmc_dev(host)) << PAGE_SHIFT;
 275
 276         mq->card = card;
 277         mq->queue = blk_init_queue(mmc_request_fn, lock);
 278         if (!mq->queue)
 279                 return -ENOMEM;
 280
 281         mq->qdepth = 2;
 282         mq->mqrq = kcalloc(mq->qdepth, sizeof(struct mmc_queue_req),
 283                            GFP_KERNEL);
 284         if (!mq->mqrq)
 285                 goto blk_cleanup;
 286         mq->mqrq_cur = &mq->mqrq[0];
 287         mq->mqrq_prev = &mq->mqrq[1];
 288         mq->queue->queuedata = mq;
 289
 290         blk_queue_prep_rq(mq->queue, mmc_prep_request);
 291         queue_flag_set_unlocked(QUEUE_FLAG_NONROT, mq->queue);
 292         queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, mq->queue);
 293         if (mmc_can_erase(card))
 294                 mmc_queue_setup_discard(mq->queue, card);
 295
 296 #ifdef CONFIG_MMC_BLOCK_BOUNCE
 297         if (host->max_segs == 1) {
 298                 unsigned int bouncesz;
 299
 300                 bouncesz = MMC_QUEUE_BOUNCESZ;
 301
 302                 if (bouncesz > host->max_req_size)
 303                         bouncesz = host->max_req_size;
 304                 if (bouncesz > host->max_seg_size)
 305                         bouncesz = host->max_seg_size;
 306                 if (bouncesz > (host->max_blk_count * 512))
 307                         bouncesz = host->max_blk_count * 512;
 308
 309                 if (bouncesz > 512 &&
 310                     mmc_queue_alloc_bounce_bufs(mq, bouncesz)) {
 311                         blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_ANY);
 312                         blk_queue_max_hw_sectors(mq->queue, bouncesz / 512);
 313                         blk_queue_max_segments(mq->queue, bouncesz / 512);
 314                         blk_queue_max_segment_size(mq->queue, bouncesz);
 315
 316                         ret = mmc_queue_alloc_bounce_sgs(mq, bouncesz);
 317                         if (ret)
 318                                 goto cleanup_queue;
 319                         bounce = true;
 320                 }
 321         }
 322 #endif
 323
 324         if (!bounce) {
 325                 blk_queue_bounce_limit(mq->queue, limit);
 326                 blk_queue_max_hw_sectors(mq->queue,
 327                         min(host->max_blk_count, host->max_req_size / 512));
 328                 blk_queue_max_segments(mq->queue, host->max_segs);
 329                 blk_queue_max_segment_size(mq->queue, host->max_seg_size);
 330
 331                 ret = mmc_queue_alloc_sgs(mq, host->max_segs);
 332                 if (ret)
 333                         goto cleanup_queue;
 334         }
 335
 336         sema_init(&mq->thread_sem, 1);
 337
 338         mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd/%d%s",
 339                 host->index, subname ? subname : "");
 340
 341         if (IS_ERR(mq->thread)) {
 342                 ret = PTR_ERR(mq->thread);
 343                 goto cleanup_queue;
 344         }
 345
 346         return 0;
 347
 348  cleanup_queue:
 349         mmc_queue_reqs_free_bufs(mq);
 350         kfree(mq->mqrq);
 351         mq->mqrq = NULL;
 352 blk_cleanup:
 353         blk_cleanup_queue(mq->queue);
 354         return ret;
 355 }
 356
 357 void mmc_cleanup_queue(struct mmc_queue *mq)
 358 {
 359         struct request_queue *q = mq->queue;
 360         unsigned long flags;
 361
 362         /* Make sure the queue isn't suspended, as that will deadlock */
 363         mmc_queue_resume(mq);
 364
 365         /* Then terminate our worker thread */
 366         kthread_stop(mq->thread);
 367
 368         /* Empty the queue */
 369         spin_lock_irqsave(q->queue_lock, flags);
 370         q->queuedata = NULL;
 371         blk_start_queue(q);
 372         spin_unlock_irqrestore(q->queue_lock, flags);
 373
 374         mmc_queue_reqs_free_bufs(mq);
 375         kfree(mq->mqrq);
 376         mq->mqrq = NULL;
 377
 378         mq->card = NULL;
 379 }
 380 EXPORT_SYMBOL(mmc_cleanup_queue);
 381
 382 /**
 383  * mmc_queue_suspend - suspend a MMC request queue
 384  * @mq: MMC queue to suspend
 385  *
 386  * Stop the block request queue, and wait for our thread to
 387  * complete any outstanding requests.  This ensures that we
 388  * won't suspend while a request is being processed.
 389  */
 390 void mmc_queue_suspend(struct mmc_queue *mq)
 391 {
 392         struct request_queue *q = mq->queue;
 393         unsigned long flags;
 394
 395         if (!mq->suspended) {
 396                 mq->suspended |= true;
 397
 398                 spin_lock_irqsave(q->queue_lock, flags);
 399                 blk_stop_queue(q);
 400                 spin_unlock_irqrestore(q->queue_lock, flags);
 401
 402                 down(&mq->thread_sem);
 403         }
 404 }
 405
 406 /**
 407  * mmc_queue_resume - resume a previously suspended MMC request queue
 408  * @mq: MMC queue to resume
 409  */
 410 void mmc_queue_resume(struct mmc_queue *mq)
 411 {
 412         struct request_queue *q = mq->queue;
 413         unsigned long flags;
 414
 415         if (mq->suspended) {
 416                 mq->suspended = false;
 417
 418                 up(&mq->thread_sem);
 419
 420                 spin_lock_irqsave(q->queue_lock, flags);
 421                 blk_start_queue(q);
 422                 spin_unlock_irqrestore(q->queue_lock, flags);
 423         }
 424 }
 425
 426 /*
 427  * Prepare the sg list(s) to be handed of to the host driver
 428  */
 429 unsigned int mmc_queue_map_sg(struct mmc_queue *mq, struct mmc_queue_req *mqrq)
 430 {
 431         unsigned int sg_len;
 432         size_t buflen;
 433         struct scatterlist *sg;
 434         int i;
 435
 436         if (!mqrq->bounce_buf)
 437                 return blk_rq_map_sg(mq->queue, mqrq->req, mqrq->sg);
 438
 439         sg_len = blk_rq_map_sg(mq->queue, mqrq->req, mqrq->bounce_sg);
 440
 441         mqrq->bounce_sg_len = sg_len;
 442
 443         buflen = 0;
 444         for_each_sg(mqrq->bounce_sg, sg, sg_len, i)
 445                 buflen += sg->length;
 446
 447         sg_init_one(mqrq->sg, mqrq->bounce_buf, buflen);
 448
 449         return 1;
 450 }
 451
 452 /*
 453  * If writing, bounce the data to the buffer before the request
 454  * is sent to the host driver
 455  */
 456 void mmc_queue_bounce_pre(struct mmc_queue_req *mqrq)
 457 {
 458         if (!mqrq->bounce_buf)
 459                 return;
 460
 461         if (rq_data_dir(mqrq->req) != WRITE)
 462                 return;
 463
 464         sg_copy_to_buffer(mqrq->bounce_sg, mqrq->bounce_sg_len,
 465                 mqrq->bounce_buf, mqrq->sg[0].length);
 466 }
 467
 468 /*
 469  * If reading, bounce the data from the buffer after the request
 470  * has been handled by the host driver
 471  */
 472 void mmc_queue_bounce_post(struct mmc_queue_req *mqrq)
 473 {
 474         if (!mqrq->bounce_buf)
 475                 return;
 476
 477         if (rq_data_dir(mqrq->req) != READ)
 478                 return;
 479
 480         sg_copy_from_buffer(mqrq->bounce_sg, mqrq->bounce_sg_len,
 481                 mqrq->bounce_buf, mqrq->sg[0].length);
 482 }