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