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
  56                 spin_lock_irq(q->queue_lock);
  57                 set_current_state(TASK_INTERRUPTIBLE);
  58                 if (!blk_queue_plugged(q))
  59                         req = blk_fetch_request(q);
  60                 mq->req = req;
  61                 spin_unlock_irq(q->queue_lock);
  62
  63                 if (!req) {
  64                         if (kthread_should_stop()) {
  65                                 set_current_state(TASK_RUNNING);
  66                                 break;
  67                         }
  68                         up(&mq->thread_sem);
  69                         schedule();
  70                         down(&mq->thread_sem);
  71                         continue;
  72                 }
  73                 set_current_state(TASK_RUNNING);
  74
  75                 mq->issue_fn(mq, req);
  76         } while (1);
  77         up(&mq->thread_sem);
  78
  79         return 0;
  80 }
  81
  82 /*
  83  * Generic MMC request handler.  This is called for any queue on a
  84  * particular host.  When the host is not busy, we look for a request
  85  * on any queue on this host, and attempt to issue it.  This may
  86  * not be the queue we were asked to process.
  87  */
  88 static void mmc_request(struct request_queue *q)
  89 {
  90         struct mmc_queue *mq = q->queuedata;
  91         struct request *req;
  92
  93         if (!mq) {
  94                 while ((req = blk_fetch_request(q)) != NULL) {
  95                         req->cmd_flags |= REQ_QUIET;
  96                         __blk_end_request_all(req, -EIO);
  97                 }
  98                 return;
  99         }
 100
 101         if (!mq->req)
 102                 wake_up_process(mq->thread);
 103 }
 104
 105 /**
 106  * mmc_init_queue - initialise a queue structure.
 107  * @mq: mmc queue
 108  * @card: mmc card to attach this queue
 109  * @lock: queue lock
 110  *
 111  * Initialise a MMC card request queue.
 112  */
 113 int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card, spinlock_t *lock)
 114 {
 115         struct mmc_host *host = card->host;
 116         u64 limit = BLK_BOUNCE_HIGH;
 117         int ret;
 118
 119         if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
 120                 limit = *mmc_dev(host)->dma_mask;
 121
 122         mq->card = card;
 123         mq->queue = blk_init_queue(mmc_request, lock);
 124         if (!mq->queue)
 125                 return -ENOMEM;
 126
 127         mq->queue->queuedata = mq;
 128         mq->req = NULL;
 129
 130         blk_queue_prep_rq(mq->queue, mmc_prep_request);
 131         queue_flag_set_unlocked(QUEUE_FLAG_NONROT, mq->queue);
 132         if (mmc_can_erase(card)) {
 133                 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mq->queue);
 134                 mq->queue->limits.max_discard_sectors = UINT_MAX;
 135                 if (card->erased_byte == 0)
 136                         mq->queue->limits.discard_zeroes_data = 1;
 137                 if (!mmc_can_trim(card) && is_power_of_2(card->erase_size)) {
 138                         mq->queue->limits.discard_granularity =
 139                                                         card->erase_size << 9;
 140                         mq->queue->limits.discard_alignment =
 141                                                         card->erase_size << 9;
 142                 }
 143                 if (mmc_can_secure_erase_trim(card))
 144                         queue_flag_set_unlocked(QUEUE_FLAG_SECDISCARD,
 145                                                 mq->queue);
 146         }
 147
 148 #ifdef CONFIG_MMC_BLOCK_BOUNCE
 149         if (host->max_segs == 1) {
 150                 unsigned int bouncesz;
 151
 152                 bouncesz = MMC_QUEUE_BOUNCESZ;
 153
 154                 if (bouncesz > host->max_req_size)
 155                         bouncesz = host->max_req_size;
 156                 if (bouncesz > host->max_seg_size)
 157                         bouncesz = host->max_seg_size;
 158                 if (bouncesz > (host->max_blk_count * 512))
 159                         bouncesz = host->max_blk_count * 512;
 160
 161                 if (bouncesz > 512) {
 162                         mq->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
 163                         if (!mq->bounce_buf) {
 164                                 printk(KERN_WARNING "%s: unable to "
 165                                         "allocate bounce buffer\n",
 166                                         mmc_card_name(card));
 167                         }
 168                 }
 169
 170                 if (mq->bounce_buf) {
 171                         blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_ANY);
 172                         blk_queue_max_hw_sectors(mq->queue, bouncesz / 512);
 173                         blk_queue_max_segments(mq->queue, bouncesz / 512);
 174                         blk_queue_max_segment_size(mq->queue, bouncesz);
 175
 176                         mq->sg = kmalloc(sizeof(struct scatterlist),
 177                                 GFP_KERNEL);
 178                         if (!mq->sg) {
 179                                 ret = -ENOMEM;
 180                                 goto cleanup_queue;
 181                         }
 182                         sg_init_table(mq->sg, 1);
 183
 184                         mq->bounce_sg = kmalloc(sizeof(struct scatterlist) *
 185                                 bouncesz / 512, GFP_KERNEL);
 186                         if (!mq->bounce_sg) {
 187                                 ret = -ENOMEM;
 188                                 goto cleanup_queue;
 189                         }
 190                         sg_init_table(mq->bounce_sg, bouncesz / 512);
 191                 }
 192         }
 193 #endif
 194
 195         if (!mq->bounce_buf) {
 196                 blk_queue_bounce_limit(mq->queue, limit);
 197                 blk_queue_max_hw_sectors(mq->queue,
 198                         min(host->max_blk_count, host->max_req_size / 512));
 199                 blk_queue_max_segments(mq->queue, host->max_segs);
 200                 blk_queue_max_segment_size(mq->queue, host->max_seg_size);
 201
 202                 mq->sg = kmalloc(sizeof(struct scatterlist) *
 203                         host->max_segs, GFP_KERNEL);
 204                 if (!mq->sg) {
 205                         ret = -ENOMEM;
 206                         goto cleanup_queue;
 207                 }
 208                 sg_init_table(mq->sg, host->max_segs);
 209         }
 210
 211         sema_init(&mq->thread_sem, 1);
 212
 213         mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd/%d",
 214                 host->index);
 215
 216         if (IS_ERR(mq->thread)) {
 217                 ret = PTR_ERR(mq->thread);
 218                 goto free_bounce_sg;
 219         }
 220
 221         return 0;
 222  free_bounce_sg:
 223         if (mq->bounce_sg)
 224                 kfree(mq->bounce_sg);
 225         mq->bounce_sg = NULL;
 226  cleanup_queue:
 227         if (mq->sg)
 228                 kfree(mq->sg);
 229         mq->sg = NULL;
 230         if (mq->bounce_buf)
 231                 kfree(mq->bounce_buf);
 232         mq->bounce_buf = NULL;
 233         blk_cleanup_queue(mq->queue);
 234         return ret;
 235 }
 236
 237 void mmc_cleanup_queue(struct mmc_queue *mq)
 238 {
 239         struct request_queue *q = mq->queue;
 240         unsigned long flags;
 241
 242         /* Make sure the queue isn't suspended, as that will deadlock */
 243         mmc_queue_resume(mq);
 244
 245         /* Then terminate our worker thread */
 246         kthread_stop(mq->thread);
 247
 248         /* Empty the queue */
 249         spin_lock_irqsave(q->queue_lock, flags);
 250         q->queuedata = NULL;
 251         blk_start_queue(q);
 252         spin_unlock_irqrestore(q->queue_lock, flags);
 253
 254         if (mq->bounce_sg)
 255                 kfree(mq->bounce_sg);
 256         mq->bounce_sg = NULL;
 257
 258         kfree(mq->sg);
 259         mq->sg = NULL;
 260
 261         if (mq->bounce_buf)
 262                 kfree(mq->bounce_buf);
 263         mq->bounce_buf = NULL;
 264
 265         mq->card = NULL;
 266 }
 267 EXPORT_SYMBOL(mmc_cleanup_queue);
 268
 269 /**
 270  * mmc_queue_suspend - suspend a MMC request queue
 271  * @mq: MMC queue to suspend
 272  *
 273  * Stop the block request queue, and wait for our thread to
 274  * complete any outstanding requests.  This ensures that we
 275  * won't suspend while a request is being processed.
 276  */
 277 void mmc_queue_suspend(struct mmc_queue *mq)
 278 {
 279         struct request_queue *q = mq->queue;
 280         unsigned long flags;
 281
 282         if (!(mq->flags & MMC_QUEUE_SUSPENDED)) {
 283                 mq->flags |= MMC_QUEUE_SUSPENDED;
 284
 285                 spin_lock_irqsave(q->queue_lock, flags);
 286                 blk_stop_queue(q);
 287                 spin_unlock_irqrestore(q->queue_lock, flags);
 288
 289                 down(&mq->thread_sem);
 290         }
 291 }
 292
 293 /**
 294  * mmc_queue_resume - resume a previously suspended MMC request queue
 295  * @mq: MMC queue to resume
 296  */
 297 void mmc_queue_resume(struct mmc_queue *mq)
 298 {
 299         struct request_queue *q = mq->queue;
 300         unsigned long flags;
 301
 302         if (mq->flags & MMC_QUEUE_SUSPENDED) {
 303                 mq->flags &= ~MMC_QUEUE_SUSPENDED;
 304
 305                 up(&mq->thread_sem);
 306
 307                 spin_lock_irqsave(q->queue_lock, flags);
 308                 blk_start_queue(q);
 309                 spin_unlock_irqrestore(q->queue_lock, flags);
 310         }
 311 }
 312
 313 /*
 314  * Prepare the sg list(s) to be handed of to the host driver
 315  */
 316 unsigned int mmc_queue_map_sg(struct mmc_queue *mq)
 317 {
 318         unsigned int sg_len;
 319         size_t buflen;
 320         struct scatterlist *sg;
 321         int i;
 322
 323         if (!mq->bounce_buf)
 324                 return blk_rq_map_sg(mq->queue, mq->req, mq->sg);
 325
 326         BUG_ON(!mq->bounce_sg);
 327
 328         sg_len = blk_rq_map_sg(mq->queue, mq->req, mq->bounce_sg);
 329
 330         mq->bounce_sg_len = sg_len;
 331
 332         buflen = 0;
 333         for_each_sg(mq->bounce_sg, sg, sg_len, i)
 334                 buflen += sg->length;
 335
 336         sg_init_one(mq->sg, mq->bounce_buf, buflen);
 337
 338         return 1;
 339 }
 340
 341 /*
 342  * If writing, bounce the data to the buffer before the request
 343  * is sent to the host driver
 344  */
 345 void mmc_queue_bounce_pre(struct mmc_queue *mq)
 346 {
 347         unsigned long flags;
 348
 349         if (!mq->bounce_buf)
 350                 return;
 351
 352         if (rq_data_dir(mq->req) != WRITE)
 353                 return;
 354
 355         local_irq_save(flags);
 356         sg_copy_to_buffer(mq->bounce_sg, mq->bounce_sg_len,
 357                 mq->bounce_buf, mq->sg[0].length);
 358         local_irq_restore(flags);
 359 }
 360
 361 /*
 362  * If reading, bounce the data from the buffer after the request
 363  * has been handled by the host driver
 364  */
 365 void mmc_queue_bounce_post(struct mmc_queue *mq)
 366 {
 367         unsigned long flags;
 368
 369         if (!mq->bounce_buf)
 370                 return;
 371
 372         if (rq_data_dir(mq->req) != READ)
 373                 return;
 374
 375         local_irq_save(flags);
 376         sg_copy_from_buffer(mq->bounce_sg, mq->bounce_sg_len,
 377                 mq->bounce_buf, mq->sg[0].length);
 378         local_irq_restore(flags);
 379 }
 380