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