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.
  34          */
  35         if (!blk_fs_request(req)) {
  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         blk_queue_ordered(mq->queue, QUEUE_ORDERED_DRAIN, NULL);
 132         queue_flag_set_unlocked(QUEUE_FLAG_NONROT, mq->queue);
 133
 134 #ifdef CONFIG_MMC_BLOCK_BOUNCE
 135         if (host->max_hw_segs == 1) {
 136                 unsigned int bouncesz;
 137
 138                 bouncesz = MMC_QUEUE_BOUNCESZ;
 139
 140                 if (bouncesz > host->max_req_size)
 141                         bouncesz = host->max_req_size;
 142                 if (bouncesz > host->max_seg_size)
 143                         bouncesz = host->max_seg_size;
 144                 if (bouncesz > (host->max_blk_count * 512))
 145                         bouncesz = host->max_blk_count * 512;
 146
 147                 if (bouncesz > 512) {
 148                         mq->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
 149                         if (!mq->bounce_buf) {
 150                                 printk(KERN_WARNING "%s: unable to "
 151                                         "allocate bounce buffer\n",
 152                                         mmc_card_name(card));
 153                         }
 154                 }
 155
 156                 if (mq->bounce_buf) {
 157                         blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_ANY);
 158                         blk_queue_max_hw_sectors(mq->queue, bouncesz / 512);
 159                         blk_queue_max_segments(mq->queue, bouncesz / 512);
 160                         blk_queue_max_segment_size(mq->queue, bouncesz);
 161
 162                         mq->sg = kmalloc(sizeof(struct scatterlist),
 163                                 GFP_KERNEL);
 164                         if (!mq->sg) {
 165                                 ret = -ENOMEM;
 166                                 goto cleanup_queue;
 167                         }
 168                         sg_init_table(mq->sg, 1);
 169
 170                         mq->bounce_sg = kmalloc(sizeof(struct scatterlist) *
 171                                 bouncesz / 512, GFP_KERNEL);
 172                         if (!mq->bounce_sg) {
 173                                 ret = -ENOMEM;
 174                                 goto cleanup_queue;
 175                         }
 176                         sg_init_table(mq->bounce_sg, bouncesz / 512);
 177                 }
 178         }
 179 #endif
 180
 181         if (!mq->bounce_buf) {
 182                 blk_queue_bounce_limit(mq->queue, limit);
 183                 blk_queue_max_hw_sectors(mq->queue,
 184                         min(host->max_blk_count, host->max_req_size / 512));
 185                 blk_queue_max_segments(mq->queue, host->max_hw_segs);
 186                 blk_queue_max_segment_size(mq->queue, host->max_seg_size);
 187
 188                 mq->sg = kmalloc(sizeof(struct scatterlist) *
 189                         host->max_phys_segs, GFP_KERNEL);
 190                 if (!mq->sg) {
 191                         ret = -ENOMEM;
 192                         goto cleanup_queue;
 193                 }
 194                 sg_init_table(mq->sg, host->max_phys_segs);
 195         }
 196
 197         init_MUTEX(&mq->thread_sem);
 198
 199         mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd");
 200         if (IS_ERR(mq->thread)) {
 201                 ret = PTR_ERR(mq->thread);
 202                 goto free_bounce_sg;
 203         }
 204
 205         return 0;
 206  free_bounce_sg:
 207         if (mq->bounce_sg)
 208                 kfree(mq->bounce_sg);
 209         mq->bounce_sg = NULL;
 210  cleanup_queue:
 211         if (mq->sg)
 212                 kfree(mq->sg);
 213         mq->sg = NULL;
 214         if (mq->bounce_buf)
 215                 kfree(mq->bounce_buf);
 216         mq->bounce_buf = NULL;
 217         blk_cleanup_queue(mq->queue);
 218         return ret;
 219 }
 220
 221 void mmc_cleanup_queue(struct mmc_queue *mq)
 222 {
 223         struct request_queue *q = mq->queue;
 224         unsigned long flags;
 225
 226         /* Make sure the queue isn't suspended, as that will deadlock */
 227         mmc_queue_resume(mq);
 228
 229         /* Then terminate our worker thread */
 230         kthread_stop(mq->thread);
 231
 232         /* Empty the queue */
 233         spin_lock_irqsave(q->queue_lock, flags);
 234         q->queuedata = NULL;
 235         blk_start_queue(q);
 236         spin_unlock_irqrestore(q->queue_lock, flags);
 237
 238         if (mq->bounce_sg)
 239                 kfree(mq->bounce_sg);
 240         mq->bounce_sg = NULL;
 241
 242         kfree(mq->sg);
 243         mq->sg = NULL;
 244
 245         if (mq->bounce_buf)
 246                 kfree(mq->bounce_buf);
 247         mq->bounce_buf = NULL;
 248
 249         mq->card = NULL;
 250 }
 251 EXPORT_SYMBOL(mmc_cleanup_queue);
 252
 253 /**
 254  * mmc_queue_suspend - suspend a MMC request queue
 255  * @mq: MMC queue to suspend
 256  *
 257  * Stop the block request queue, and wait for our thread to
 258  * complete any outstanding requests.  This ensures that we
 259  * won't suspend while a request is being processed.
 260  */
 261 void mmc_queue_suspend(struct mmc_queue *mq)
 262 {
 263         struct request_queue *q = mq->queue;
 264         unsigned long flags;
 265
 266         if (!(mq->flags & MMC_QUEUE_SUSPENDED)) {
 267                 mq->flags |= MMC_QUEUE_SUSPENDED;
 268
 269                 spin_lock_irqsave(q->queue_lock, flags);
 270                 blk_stop_queue(q);
 271                 spin_unlock_irqrestore(q->queue_lock, flags);
 272
 273                 down(&mq->thread_sem);
 274         }
 275 }
 276
 277 /**
 278  * mmc_queue_resume - resume a previously suspended MMC request queue
 279  * @mq: MMC queue to resume
 280  */
 281 void mmc_queue_resume(struct mmc_queue *mq)
 282 {
 283         struct request_queue *q = mq->queue;
 284         unsigned long flags;
 285
 286         if (mq->flags & MMC_QUEUE_SUSPENDED) {
 287                 mq->flags &= ~MMC_QUEUE_SUSPENDED;
 288
 289                 up(&mq->thread_sem);
 290
 291                 spin_lock_irqsave(q->queue_lock, flags);
 292                 blk_start_queue(q);
 293                 spin_unlock_irqrestore(q->queue_lock, flags);
 294         }
 295 }
 296
 297 /*
 298  * Prepare the sg list(s) to be handed of to the host driver
 299  */
 300 unsigned int mmc_queue_map_sg(struct mmc_queue *mq)
 301 {
 302         unsigned int sg_len;
 303         size_t buflen;
 304         struct scatterlist *sg;
 305         int i;
 306
 307         if (!mq->bounce_buf)
 308                 return blk_rq_map_sg(mq->queue, mq->req, mq->sg);
 309
 310         BUG_ON(!mq->bounce_sg);
 311
 312         sg_len = blk_rq_map_sg(mq->queue, mq->req, mq->bounce_sg);
 313
 314         mq->bounce_sg_len = sg_len;
 315
 316         buflen = 0;
 317         for_each_sg(mq->bounce_sg, sg, sg_len, i)
 318                 buflen += sg->length;
 319
 320         sg_init_one(mq->sg, mq->bounce_buf, buflen);
 321
 322         return 1;
 323 }
 324
 325 /*
 326  * If writing, bounce the data to the buffer before the request
 327  * is sent to the host driver
 328  */
 329 void mmc_queue_bounce_pre(struct mmc_queue *mq)
 330 {
 331         unsigned long flags;
 332
 333         if (!mq->bounce_buf)
 334                 return;
 335
 336         if (rq_data_dir(mq->req) != WRITE)
 337                 return;
 338
 339         local_irq_save(flags);
 340         sg_copy_to_buffer(mq->bounce_sg, mq->bounce_sg_len,
 341                 mq->bounce_buf, mq->sg[0].length);
 342         local_irq_restore(flags);
 343 }
 344
 345 /*
 346  * If reading, bounce the data from the buffer after the request
 347  * has been handled by the host driver
 348  */
 349 void mmc_queue_bounce_post(struct mmc_queue *mq)
 350 {
 351         unsigned long flags;
 352
 353         if (!mq->bounce_buf)
 354                 return;
 355
 356         if (rq_data_dir(mq->req) != READ)
 357                 return;
 358
 359         local_irq_save(flags);
 360         sg_copy_from_buffer(mq->bounce_sg, mq->bounce_sg_len,
 361                 mq->bounce_buf, mq->sg[0].length);
 362         local_irq_restore(flags);
 363 }
 364