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;
  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->qcnt)
  67                                 cntx->is_waiting_last_req = true;
  68                         else
  69                                 mq->asleep = true;
  70                 }
  71                 spin_unlock_irq(q->queue_lock);
  72
  73                 if (req || mq->qcnt) {
  74                         set_current_state(TASK_RUNNING);
  75                         mmc_blk_issue_rq(mq, req);
  76                         cond_resched();
  77                 } else {
  78                         if (kthread_should_stop()) {
  79                                 set_current_state(TASK_RUNNING);
  80                                 break;
  81                         }
  82                         up(&mq->thread_sem);
  83                         schedule();
  84                         down(&mq->thread_sem);
  85                 }
  86         } while (1);
  87         up(&mq->thread_sem);
  88
  89         return 0;
  90 }
  91
  92 /*
  93  * Generic MMC request handler.  This is called for any queue on a
  94  * particular host.  When the host is not busy, we look for a request
  95  * on any queue on this host, and attempt to issue it.  This may
  96  * not be the queue we were asked to process.
  97  */
  98 static void mmc_request_fn(struct request_queue *q)
  99 {
 100         struct mmc_queue *mq = q->queuedata;
 101         struct request *req;
 102         struct mmc_context_info *cntx;
 103
 104         if (!mq) {
 105                 while ((req = blk_fetch_request(q)) != NULL) {
 106                         req->rq_flags |= RQF_QUIET;
 107                         __blk_end_request_all(req, BLK_STS_IOERR);
 108                 }
 109                 return;
 110         }
 111
 112         cntx = &mq->card->host->context_info;
 113
 114         if (cntx->is_waiting_last_req) {
 115                 cntx->is_new_req = true;
 116                 wake_up_interruptible(&cntx->wait);
 117         }
 118
 119         if (mq->asleep)
 120                 wake_up_process(mq->thread);
 121 }
 122
 123 static struct scatterlist *mmc_alloc_sg(int sg_len, gfp_t gfp)
 124 {
 125         struct scatterlist *sg;
 126
 127         sg = kmalloc_array(sg_len, sizeof(*sg), gfp);
 128         if (sg)
 129                 sg_init_table(sg, sg_len);
 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         blk_queue_max_discard_sectors(q, max_discard);
 145         q->limits.discard_granularity = card->pref_erase << 9;
 146         /* granularity must not be greater than max. discard */
 147         if (card->pref_erase > max_discard)
 148                 q->limits.discard_granularity = 0;
 149         if (mmc_can_secure_erase_trim(card))
 150                 queue_flag_set_unlocked(QUEUE_FLAG_SECERASE, q);
 151 }
 152
 153 static unsigned int mmc_queue_calc_bouncesz(struct mmc_host *host)
 154 {
 155         unsigned int bouncesz = MMC_QUEUE_BOUNCESZ;
 156
 157         if (host->max_segs != 1 || (host->caps & MMC_CAP_NO_BOUNCE_BUFF))
 158                 return 0;
 159
 160         if (bouncesz > host->max_req_size)
 161                 bouncesz = host->max_req_size;
 162         if (bouncesz > host->max_seg_size)
 163                 bouncesz = host->max_seg_size;
 164         if (bouncesz > host->max_blk_count * 512)
 165                 bouncesz = host->max_blk_count * 512;
 166
 167         if (bouncesz <= 512)
 168                 return 0;
 169
 170         return bouncesz;
 171 }
 172
 173 /**
 174  * mmc_init_request() - initialize the MMC-specific per-request data
 175  * @q: the request queue
 176  * @req: the request
 177  * @gfp: memory allocation policy
 178  */
 179 static int mmc_init_request(struct request_queue *q, struct request *req,
 180                             gfp_t gfp)
 181 {
 182         struct mmc_queue_req *mq_rq = req_to_mmc_queue_req(req);
 183         struct mmc_queue *mq = q->queuedata;
 184         struct mmc_card *card = mq->card;
 185         struct mmc_host *host = card->host;
 186
 187         if (card->bouncesz) {
 188                 mq_rq->bounce_buf = kmalloc(card->bouncesz, gfp);
 189                 if (!mq_rq->bounce_buf)
 190                         return -ENOMEM;
 191                 if (card->bouncesz > 512) {
 192                         mq_rq->sg = mmc_alloc_sg(1, gfp);
 193                         if (!mq_rq->sg)
 194                                 return -ENOMEM;
 195                         mq_rq->bounce_sg = mmc_alloc_sg(card->bouncesz / 512,
 196                                                         gfp);
 197                         if (!mq_rq->bounce_sg)
 198                                 return -ENOMEM;
 199                 }
 200         } else {
 201                 mq_rq->bounce_buf = NULL;
 202                 mq_rq->bounce_sg = NULL;
 203                 mq_rq->sg = mmc_alloc_sg(host->max_segs, gfp);
 204                 if (!mq_rq->sg)
 205                         return -ENOMEM;
 206         }
 207
 208         return 0;
 209 }
 210
 211 static void mmc_exit_request(struct request_queue *q, struct request *req)
 212 {
 213         struct mmc_queue_req *mq_rq = req_to_mmc_queue_req(req);
 214
 215         /* It is OK to kfree(NULL) so this will be smooth */
 216         kfree(mq_rq->bounce_sg);
 217         mq_rq->bounce_sg = NULL;
 218
 219         kfree(mq_rq->bounce_buf);
 220         mq_rq->bounce_buf = NULL;
 221
 222         kfree(mq_rq->sg);
 223         mq_rq->sg = NULL;
 224 }
 225
 226 /**
 227  * mmc_init_queue - initialise a queue structure.
 228  * @mq: mmc queue
 229  * @card: mmc card to attach this queue
 230  * @lock: queue lock
 231  * @subname: partition subname
 232  *
 233  * Initialise a MMC card request queue.
 234  */
 235 int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card,
 236                    spinlock_t *lock, const char *subname)
 237 {
 238         struct mmc_host *host = card->host;
 239         u64 limit = BLK_BOUNCE_HIGH;
 240         int ret = -ENOMEM;
 241
 242         if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
 243                 limit = (u64)dma_max_pfn(mmc_dev(host)) << PAGE_SHIFT;
 244
 245         mq->card = card;
 246         mq->queue = blk_alloc_queue(GFP_KERNEL);
 247         if (!mq->queue)
 248                 return -ENOMEM;
 249         mq->queue->queue_lock = lock;
 250         mq->queue->request_fn = mmc_request_fn;
 251         mq->queue->init_rq_fn = mmc_init_request;
 252         mq->queue->exit_rq_fn = mmc_exit_request;
 253         mq->queue->cmd_size = sizeof(struct mmc_queue_req);
 254         mq->queue->queuedata = mq;
 255         mq->qcnt = 0;
 256         ret = blk_init_allocated_queue(mq->queue);
 257         if (ret) {
 258                 blk_cleanup_queue(mq->queue);
 259                 return ret;
 260         }
 261
 262         blk_queue_prep_rq(mq->queue, mmc_prep_request);
 263         queue_flag_set_unlocked(QUEUE_FLAG_NONROT, mq->queue);
 264         queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, mq->queue);
 265         if (mmc_can_erase(card))
 266                 mmc_queue_setup_discard(mq->queue, card);
 267
 268         card->bouncesz = mmc_queue_calc_bouncesz(host);
 269         if (card->bouncesz) {
 270                 blk_queue_max_hw_sectors(mq->queue, card->bouncesz / 512);
 271                 blk_queue_max_segments(mq->queue, card->bouncesz / 512);
 272                 blk_queue_max_segment_size(mq->queue, card->bouncesz);
 273         } else {
 274                 blk_queue_bounce_limit(mq->queue, limit);
 275                 blk_queue_max_hw_sectors(mq->queue,
 276                         min(host->max_blk_count, host->max_req_size / 512));
 277                 blk_queue_max_segments(mq->queue, host->max_segs);
 278                 blk_queue_max_segment_size(mq->queue, host->max_seg_size);
 279         }
 280
 281         sema_init(&mq->thread_sem, 1);
 282
 283         mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd/%d%s",
 284                 host->index, subname ? subname : "");
 285
 286         if (IS_ERR(mq->thread)) {
 287                 ret = PTR_ERR(mq->thread);
 288                 goto cleanup_queue;
 289         }
 290
 291         return 0;
 292
 293 cleanup_queue:
 294         blk_cleanup_queue(mq->queue);
 295         return ret;
 296 }
 297
 298 void mmc_cleanup_queue(struct mmc_queue *mq)
 299 {
 300         struct request_queue *q = mq->queue;
 301         unsigned long flags;
 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         mq->card = NULL;
 316 }
 317 EXPORT_SYMBOL(mmc_cleanup_queue);
 318
 319 /**
 320  * mmc_queue_suspend - suspend a MMC request queue
 321  * @mq: MMC queue to suspend
 322  *
 323  * Stop the block request queue, and wait for our thread to
 324  * complete any outstanding requests.  This ensures that we
 325  * won't suspend while a request is being processed.
 326  */
 327 void mmc_queue_suspend(struct mmc_queue *mq)
 328 {
 329         struct request_queue *q = mq->queue;
 330         unsigned long flags;
 331
 332         if (!mq->suspended) {
 333                 mq->suspended |= true;
 334
 335                 spin_lock_irqsave(q->queue_lock, flags);
 336                 blk_stop_queue(q);
 337                 spin_unlock_irqrestore(q->queue_lock, flags);
 338
 339                 down(&mq->thread_sem);
 340         }
 341 }
 342
 343 /**
 344  * mmc_queue_resume - resume a previously suspended MMC request queue
 345  * @mq: MMC queue to resume
 346  */
 347 void mmc_queue_resume(struct mmc_queue *mq)
 348 {
 349         struct request_queue *q = mq->queue;
 350         unsigned long flags;
 351
 352         if (mq->suspended) {
 353                 mq->suspended = false;
 354
 355                 up(&mq->thread_sem);
 356
 357                 spin_lock_irqsave(q->queue_lock, flags);
 358                 blk_start_queue(q);
 359                 spin_unlock_irqrestore(q->queue_lock, flags);
 360         }
 361 }
 362
 363 /*
 364  * Prepare the sg list(s) to be handed of to the host driver
 365  */
 366 unsigned int mmc_queue_map_sg(struct mmc_queue *mq, struct mmc_queue_req *mqrq)
 367 {
 368         unsigned int sg_len;
 369         size_t buflen;
 370         struct scatterlist *sg;
 371         struct request *req = mmc_queue_req_to_req(mqrq);
 372         int i;
 373
 374         if (!mqrq->bounce_buf)
 375                 return blk_rq_map_sg(mq->queue, req, mqrq->sg);
 376
 377         sg_len = blk_rq_map_sg(mq->queue, req, mqrq->bounce_sg);
 378
 379         mqrq->bounce_sg_len = sg_len;
 380
 381         buflen = 0;
 382         for_each_sg(mqrq->bounce_sg, sg, sg_len, i)
 383                 buflen += sg->length;
 384
 385         sg_init_one(mqrq->sg, mqrq->bounce_buf, buflen);
 386
 387         return 1;
 388 }
 389
 390 /*
 391  * If writing, bounce the data to the buffer before the request
 392  * is sent to the host driver
 393  */
 394 void mmc_queue_bounce_pre(struct mmc_queue_req *mqrq)
 395 {
 396         if (!mqrq->bounce_buf)
 397                 return;
 398
 399         if (rq_data_dir(mmc_queue_req_to_req(mqrq)) != WRITE)
 400                 return;
 401
 402         sg_copy_to_buffer(mqrq->bounce_sg, mqrq->bounce_sg_len,
 403                 mqrq->bounce_buf, mqrq->sg[0].length);
 404 }
 405
 406 /*
 407  * If reading, bounce the data from the buffer after the request
 408  * has been handled by the host driver
 409  */
 410 void mmc_queue_bounce_post(struct mmc_queue_req *mqrq)
 411 {
 412         if (!mqrq->bounce_buf)
 413                 return;
 414
 415         if (rq_data_dir(mmc_queue_req_to_req(mqrq)) != READ)
 416                 return;
 417
 418         sg_copy_from_buffer(mqrq->bounce_sg, mqrq->bounce_sg_len,
 419                 mqrq->bounce_buf, mqrq->sg[0].length);
 420 }