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                 req = blk_fetch_request(q);
  59                 mq->req = req;
  60                 spin_unlock_irq(q->queue_lock);
  61
  62                 if (!req) {
  63                         if (kthread_should_stop()) {
  64                                 set_current_state(TASK_RUNNING);
  65                                 break;
  66                         }
  67                         up(&mq->thread_sem);
  68                         schedule();
  69                         down(&mq->thread_sem);
  70                         continue;
  71                 }
  72                 set_current_state(TASK_RUNNING);
  73
  74                 mq->issue_fn(mq, req);
  75         } while (1);
  76         up(&mq->thread_sem);
  77
  78         return 0;
  79 }
  80
  81 /*
  82  * Generic MMC request handler.  This is called for any queue on a
  83  * particular host.  When the host is not busy, we look for a request
  84  * on any queue on this host, and attempt to issue it.  This may
  85  * not be the queue we were asked to process.
  86  */
  87 static void mmc_request(struct request_queue *q)
  88 {
  89         struct mmc_queue *mq = q->queuedata;
  90         struct request *req;
  91
  92         if (!mq) {
  93                 while ((req = blk_fetch_request(q)) != NULL) {
  94                         req->cmd_flags |= REQ_QUIET;
  95                         __blk_end_request_all(req, -EIO);
  96                 }
  97                 return;
  98         }
  99
 100         if (!mq->req)
 101                 wake_up_process(mq->thread);
 102 }
 103
 104 static void mmc_queue_setup_discard(struct request_queue *q,
 105                                     struct mmc_card *card)
 106 {
 107         unsigned max_discard;
 108
 109         max_discard = mmc_calc_max_discard(card);
 110         if (!max_discard)
 111                 return;
 112
 113         queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
 114         q->limits.max_discard_sectors = max_discard;
 115         if (card->erased_byte == 0)
 116                 q->limits.discard_zeroes_data = 1;
 117         q->limits.discard_granularity = card->pref_erase << 9;
 118         /* granularity must not be greater than max. discard */
 119         if (card->pref_erase > max_discard)
 120                 q->limits.discard_granularity = 0;
 121         if (mmc_can_secure_erase_trim(card))
 122                 queue_flag_set_unlocked(QUEUE_FLAG_SECDISCARD, q);
 123 }
 124
 125 /**
 126  * mmc_init_queue - initialise a queue structure.
 127  * @mq: mmc queue
 128  * @card: mmc card to attach this queue
 129  * @lock: queue lock
 130  * @subname: partition subname
 131  *
 132  * Initialise a MMC card request queue.
 133  */
 134 int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card,
 135                    spinlock_t *lock, const char *subname)
 136 {
 137         struct mmc_host *host = card->host;
 138         u64 limit = BLK_BOUNCE_HIGH;
 139         int ret;
 140
 141         if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
 142                 limit = *mmc_dev(host)->dma_mask;
 143
 144         mq->card = card;
 145         mq->queue = blk_init_queue(mmc_request, lock);
 146         if (!mq->queue)
 147                 return -ENOMEM;
 148
 149         mq->queue->queuedata = mq;
 150         mq->req = NULL;
 151
 152         blk_queue_prep_rq(mq->queue, mmc_prep_request);
 153         queue_flag_set_unlocked(QUEUE_FLAG_NONROT, mq->queue);
 154         if (mmc_can_erase(card))
 155                 mmc_queue_setup_discard(mq->queue, card);
 156
 157 #ifdef CONFIG_MMC_BLOCK_BOUNCE
 158         if (host->max_segs == 1) {
 159                 unsigned int bouncesz;
 160
 161                 bouncesz = MMC_QUEUE_BOUNCESZ;
 162
 163                 if (bouncesz > host->max_req_size)
 164                         bouncesz = host->max_req_size;
 165                 if (bouncesz > host->max_seg_size)
 166                         bouncesz = host->max_seg_size;
 167                 if (bouncesz > (host->max_blk_count * 512))
 168                         bouncesz = host->max_blk_count * 512;
 169
 170                 if (bouncesz > 512) {
 171                         mq->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
 172                         if (!mq->bounce_buf) {
 173                                 printk(KERN_WARNING "%s: unable to "
 174                                         "allocate bounce buffer\n",
 175                                         mmc_card_name(card));
 176                         }
 177                 }
 178
 179                 if (mq->bounce_buf) {
 180                         blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_ANY);
 181                         blk_queue_max_hw_sectors(mq->queue, bouncesz / 512);
 182                         blk_queue_max_segments(mq->queue, bouncesz / 512);
 183                         blk_queue_max_segment_size(mq->queue, bouncesz);
 184
 185                         mq->sg = kmalloc(sizeof(struct scatterlist),
 186                                 GFP_KERNEL);
 187                         if (!mq->sg) {
 188                                 ret = -ENOMEM;
 189                                 goto cleanup_queue;
 190                         }
 191                         sg_init_table(mq->sg, 1);
 192
 193                         mq->bounce_sg = kmalloc(sizeof(struct scatterlist) *
 194                                 bouncesz / 512, GFP_KERNEL);
 195                         if (!mq->bounce_sg) {
 196                                 ret = -ENOMEM;
 197                                 goto cleanup_queue;
 198                         }
 199                         sg_init_table(mq->bounce_sg, bouncesz / 512);
 200                 }
 201         }
 202 #endif
 203
 204         if (!mq->bounce_buf) {
 205                 blk_queue_bounce_limit(mq->queue, limit);
 206                 blk_queue_max_hw_sectors(mq->queue,
 207                         min(host->max_blk_count, host->max_req_size / 512));
 208                 blk_queue_max_segments(mq->queue, host->max_segs);
 209                 blk_queue_max_segment_size(mq->queue, host->max_seg_size);
 210
 211                 mq->sg = kmalloc(sizeof(struct scatterlist) *
 212                         host->max_segs, GFP_KERNEL);
 213                 if (!mq->sg) {
 214                         ret = -ENOMEM;
 215                         goto cleanup_queue;
 216                 }
 217                 sg_init_table(mq->sg, host->max_segs);
 218         }
 219
 220         sema_init(&mq->thread_sem, 1);
 221
 222         mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd/%d%s",
 223                 host->index, subname ? subname : "");
 224
 225         if (IS_ERR(mq->thread)) {
 226                 ret = PTR_ERR(mq->thread);
 227                 goto free_bounce_sg;
 228         }
 229
 230         return 0;
 231  free_bounce_sg:
 232         if (mq->bounce_sg)
 233                 kfree(mq->bounce_sg);
 234         mq->bounce_sg = NULL;
 235  cleanup_queue:
 236         if (mq->sg)
 237                 kfree(mq->sg);
 238         mq->sg = NULL;
 239         if (mq->bounce_buf)
 240                 kfree(mq->bounce_buf);
 241         mq->bounce_buf = NULL;
 242         blk_cleanup_queue(mq->queue);
 243         return ret;
 244 }
 245
 246 void mmc_cleanup_queue(struct mmc_queue *mq)
 247 {
 248         struct request_queue *q = mq->queue;
 249         unsigned long flags;
 250
 251         /* Make sure the queue isn't suspended, as that will deadlock */
 252         mmc_queue_resume(mq);
 253
 254         /* Then terminate our worker thread */
 255         kthread_stop(mq->thread);
 256
 257         /* Empty the queue */
 258         spin_lock_irqsave(q->queue_lock, flags);
 259         q->queuedata = NULL;
 260         blk_start_queue(q);
 261         spin_unlock_irqrestore(q->queue_lock, flags);
 262
 263         if (mq->bounce_sg)
 264                 kfree(mq->bounce_sg);
 265         mq->bounce_sg = NULL;
 266
 267         kfree(mq->sg);
 268         mq->sg = NULL;
 269
 270         if (mq->bounce_buf)
 271                 kfree(mq->bounce_buf);
 272         mq->bounce_buf = NULL;
 273
 274         mq->card = NULL;
 275 }
 276 EXPORT_SYMBOL(mmc_cleanup_queue);
 277
 278 /**
 279  * mmc_queue_suspend - suspend a MMC request queue
 280  * @mq: MMC queue to suspend
 281  *
 282  * Stop the block request queue, and wait for our thread to
 283  * complete any outstanding requests.  This ensures that we
 284  * won't suspend while a request is being processed.
 285  */
 286 void mmc_queue_suspend(struct mmc_queue *mq)
 287 {
 288         struct request_queue *q = mq->queue;
 289         unsigned long flags;
 290
 291         if (!(mq->flags & MMC_QUEUE_SUSPENDED)) {
 292                 mq->flags |= MMC_QUEUE_SUSPENDED;
 293
 294                 spin_lock_irqsave(q->queue_lock, flags);
 295                 blk_stop_queue(q);
 296                 spin_unlock_irqrestore(q->queue_lock, flags);
 297
 298                 down(&mq->thread_sem);
 299         }
 300 }
 301
 302 /**
 303  * mmc_queue_resume - resume a previously suspended MMC request queue
 304  * @mq: MMC queue to resume
 305  */
 306 void mmc_queue_resume(struct mmc_queue *mq)
 307 {
 308         struct request_queue *q = mq->queue;
 309         unsigned long flags;
 310
 311         if (mq->flags & MMC_QUEUE_SUSPENDED) {
 312                 mq->flags &= ~MMC_QUEUE_SUSPENDED;
 313
 314                 up(&mq->thread_sem);
 315
 316                 spin_lock_irqsave(q->queue_lock, flags);
 317                 blk_start_queue(q);
 318                 spin_unlock_irqrestore(q->queue_lock, flags);
 319         }
 320 }
 321
 322 /*
 323  * Prepare the sg list(s) to be handed of to the host driver
 324  */
 325 unsigned int mmc_queue_map_sg(struct mmc_queue *mq)
 326 {
 327         unsigned int sg_len;
 328         size_t buflen;
 329         struct scatterlist *sg;
 330         int i;
 331
 332         if (!mq->bounce_buf)
 333                 return blk_rq_map_sg(mq->queue, mq->req, mq->sg);
 334
 335         BUG_ON(!mq->bounce_sg);
 336
 337         sg_len = blk_rq_map_sg(mq->queue, mq->req, mq->bounce_sg);
 338
 339         mq->bounce_sg_len = sg_len;
 340
 341         buflen = 0;
 342         for_each_sg(mq->bounce_sg, sg, sg_len, i)
 343                 buflen += sg->length;
 344
 345         sg_init_one(mq->sg, mq->bounce_buf, buflen);
 346
 347         return 1;
 348 }
 349
 350 /*
 351  * If writing, bounce the data to the buffer before the request
 352  * is sent to the host driver
 353  */
 354 void mmc_queue_bounce_pre(struct mmc_queue *mq)
 355 {
 356         if (!mq->bounce_buf)
 357                 return;
 358
 359         if (rq_data_dir(mq->req) != WRITE)
 360                 return;
 361
 362         sg_copy_to_buffer(mq->bounce_sg, mq->bounce_sg_len,
 363                 mq->bounce_buf, mq->sg[0].length);
 364 }
 365
 366 /*
 367  * If reading, bounce the data from the buffer after the request
 368  * has been handled by the host driver
 369  */
 370 void mmc_queue_bounce_post(struct mmc_queue *mq)
 371 {
 372         if (!mq->bounce_buf)
 373                 return;
 374
 375         if (rq_data_dir(mq->req) != READ)
 376                 return;
 377
 378         sg_copy_from_buffer(mq->bounce_sg, mq->bounce_sg_len,
 379                 mq->bounce_buf, mq->sg[0].length);
 380 }
 381