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