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   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/module.h>
  13 #include <linux/blkdev.h>
  14 #include <linux/freezer.h>
  15 #include <linux/kthread.h>
  16 #include <linux/scatterlist.h>
  17
  18 #include <linux/mmc/card.h>
  19 #include <linux/mmc/host.h>
  20 #include "queue.h"
  21
  22 #define MMC_QUEUE_BOUNCESZ      65536
  23
  24 #define MMC_QUEUE_SUSPENDED     (1 << 0)
  25
  26 /*
  27  * Prepare a MMC request. This just filters out odd stuff.
  28  */
  29 static int mmc_prep_request(struct request_queue *q, struct request *req)
  30 {
  31         /*
  32          * We only like normal block requests.
  33          */
  34         if (!blk_fs_request(req)) {
  35                 blk_dump_rq_flags(req, "MMC bad request");
  36                 return BLKPREP_KILL;
  37         }
  38
  39         req->cmd_flags |= REQ_DONTPREP;
  40
  41         return BLKPREP_OK;
  42 }
  43
  44 static int mmc_queue_thread(void *d)
  45 {
  46         struct mmc_queue *mq = d;
  47         struct request_queue *q = mq->queue;
  48
  49         current->flags |= PF_MEMALLOC;
  50
  51         down(&mq->thread_sem);
  52         do {
  53                 struct request *req = NULL;
  54
  55                 spin_lock_irq(q->queue_lock);
  56                 set_current_state(TASK_INTERRUPTIBLE);
  57                 if (!blk_queue_plugged(q))
  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                 printk(KERN_ERR "MMC: killing requests for dead queue\n");
  94                 while ((req = blk_fetch_request(q)) != NULL)
  95                         __blk_end_request_all(req, -EIO);
  96                 return;
  97         }
  98
  99         if (!mq->req)
 100                 wake_up_process(mq->thread);
 101 }
 102
 103 /**
 104  * mmc_init_queue - initialise a queue structure.
 105  * @mq: mmc queue
 106  * @card: mmc card to attach this queue
 107  * @lock: queue lock
 108  *
 109  * Initialise a MMC card request queue.
 110  */
 111 int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card, spinlock_t *lock)
 112 {
 113         struct mmc_host *host = card->host;
 114         u64 limit = BLK_BOUNCE_HIGH;
 115         int ret;
 116
 117         if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
 118                 limit = *mmc_dev(host)->dma_mask;
 119
 120         mq->card = card;
 121         mq->queue = blk_init_queue(mmc_request, lock);
 122         if (!mq->queue)
 123                 return -ENOMEM;
 124
 125         mq->queue->queuedata = mq;
 126         mq->req = NULL;
 127
 128         blk_queue_prep_rq(mq->queue, mmc_prep_request);
 129         blk_queue_ordered(mq->queue, QUEUE_ORDERED_DRAIN, NULL);
 130         queue_flag_set_unlocked(QUEUE_FLAG_NONROT, mq->queue);
 131
 132 #ifdef CONFIG_MMC_BLOCK_BOUNCE
 133         if (host->max_hw_segs == 1) {
 134                 unsigned int bouncesz;
 135
 136                 bouncesz = MMC_QUEUE_BOUNCESZ;
 137
 138                 if (bouncesz > host->max_req_size)
 139                         bouncesz = host->max_req_size;
 140                 if (bouncesz > host->max_seg_size)
 141                         bouncesz = host->max_seg_size;
 142                 if (bouncesz > (host->max_blk_count * 512))
 143                         bouncesz = host->max_blk_count * 512;
 144
 145                 if (bouncesz > 512) {
 146                         mq->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
 147                         if (!mq->bounce_buf) {
 148                                 printk(KERN_WARNING "%s: unable to "
 149                                         "allocate bounce buffer\n",
 150                                         mmc_card_name(card));
 151                         }
 152                 }
 153
 154                 if (mq->bounce_buf) {
 155                         blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_ANY);
 156                         blk_queue_max_sectors(mq->queue, bouncesz / 512);
 157                         blk_queue_max_phys_segments(mq->queue, bouncesz / 512);
 158                         blk_queue_max_hw_segments(mq->queue, bouncesz / 512);
 159                         blk_queue_max_segment_size(mq->queue, bouncesz);
 160
 161                         mq->sg = kmalloc(sizeof(struct scatterlist),
 162                                 GFP_KERNEL);
 163                         if (!mq->sg) {
 164                                 ret = -ENOMEM;
 165                                 goto cleanup_queue;
 166                         }
 167                         sg_init_table(mq->sg, 1);
 168
 169                         mq->bounce_sg = kmalloc(sizeof(struct scatterlist) *
 170                                 bouncesz / 512, GFP_KERNEL);
 171                         if (!mq->bounce_sg) {
 172                                 ret = -ENOMEM;
 173                                 goto cleanup_queue;
 174                         }
 175                         sg_init_table(mq->bounce_sg, bouncesz / 512);
 176                 }
 177         }
 178 #endif
 179
 180         if (!mq->bounce_buf) {
 181                 blk_queue_bounce_limit(mq->queue, limit);
 182                 blk_queue_max_sectors(mq->queue,
 183                         min(host->max_blk_count, host->max_req_size / 512));
 184                 blk_queue_max_phys_segments(mq->queue, host->max_phys_segs);
 185                 blk_queue_max_hw_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         /* Mark that we should start throwing out stragglers */
 227         spin_lock_irqsave(q->queue_lock, flags);
 228         q->queuedata = NULL;
 229         spin_unlock_irqrestore(q->queue_lock, flags);
 230
 231         /* Make sure the queue isn't suspended, as that will deadlock */
 232         mmc_queue_resume(mq);
 233
 234         /* Then terminate our worker thread */
 235         kthread_stop(mq->thread);
 236
 237         if (mq->bounce_sg)
 238                 kfree(mq->bounce_sg);
 239         mq->bounce_sg = NULL;
 240
 241         kfree(mq->sg);
 242         mq->sg = NULL;
 243
 244         if (mq->bounce_buf)
 245                 kfree(mq->bounce_buf);
 246         mq->bounce_buf = NULL;
 247
 248         blk_cleanup_queue(mq->queue);
 249
 250         mq->card = NULL;
 251 }
 252 EXPORT_SYMBOL(mmc_cleanup_queue);
 253
 254 /**
 255  * mmc_queue_suspend - suspend a MMC request queue
 256  * @mq: MMC queue to suspend
 257  *
 258  * Stop the block request queue, and wait for our thread to
 259  * complete any outstanding requests.  This ensures that we
 260  * won't suspend while a request is being processed.
 261  */
 262 void mmc_queue_suspend(struct mmc_queue *mq)
 263 {
 264         struct request_queue *q = mq->queue;
 265         unsigned long flags;
 266
 267         if (!(mq->flags & MMC_QUEUE_SUSPENDED)) {
 268                 mq->flags |= MMC_QUEUE_SUSPENDED;
 269
 270                 spin_lock_irqsave(q->queue_lock, flags);
 271                 blk_stop_queue(q);
 272                 spin_unlock_irqrestore(q->queue_lock, flags);
 273
 274                 down(&mq->thread_sem);
 275         }
 276 }
 277
 278 /**
 279  * mmc_queue_resume - resume a previously suspended MMC request queue
 280  * @mq: MMC queue to resume
 281  */
 282 void mmc_queue_resume(struct mmc_queue *mq)
 283 {
 284         struct request_queue *q = mq->queue;
 285         unsigned long flags;
 286
 287         if (mq->flags & MMC_QUEUE_SUSPENDED) {
 288                 mq->flags &= ~MMC_QUEUE_SUSPENDED;
 289
 290                 up(&mq->thread_sem);
 291
 292                 spin_lock_irqsave(q->queue_lock, flags);
 293                 blk_start_queue(q);
 294                 spin_unlock_irqrestore(q->queue_lock, flags);
 295         }
 296 }
 297
 298 /*
 299  * Prepare the sg list(s) to be handed of to the host driver
 300  */
 301 unsigned int mmc_queue_map_sg(struct mmc_queue *mq)
 302 {
 303         unsigned int sg_len;
 304         size_t buflen;
 305         struct scatterlist *sg;
 306         int i;
 307
 308         if (!mq->bounce_buf)
 309                 return blk_rq_map_sg(mq->queue, mq->req, mq->sg);
 310
 311         BUG_ON(!mq->bounce_sg);
 312
 313         sg_len = blk_rq_map_sg(mq->queue, mq->req, mq->bounce_sg);
 314
 315         mq->bounce_sg_len = sg_len;
 316
 317         buflen = 0;
 318         for_each_sg(mq->bounce_sg, sg, sg_len, i)
 319                 buflen += sg->length;
 320
 321         sg_init_one(mq->sg, mq->bounce_buf, buflen);
 322
 323         return 1;
 324 }
 325
 326 /*
 327  * If writing, bounce the data to the buffer before the request
 328  * is sent to the host driver
 329  */
 330 void mmc_queue_bounce_pre(struct mmc_queue *mq)
 331 {
 332         unsigned long flags;
 333
 334         if (!mq->bounce_buf)
 335                 return;
 336
 337         if (rq_data_dir(mq->req) != WRITE)
 338                 return;
 339
 340         local_irq_save(flags);
 341         sg_copy_to_buffer(mq->bounce_sg, mq->bounce_sg_len,
 342                 mq->bounce_buf, mq->sg[0].length);
 343         local_irq_restore(flags);
 344 }
 345
 346 /*
 347  * If reading, bounce the data from the buffer after the request
 348  * has been handled by the host driver
 349  */
 350 void mmc_queue_bounce_post(struct mmc_queue *mq)
 351 {
 352         unsigned long flags;
 353
 354         if (!mq->bounce_buf)
 355                 return;
 356
 357         if (rq_data_dir(mq->req) != READ)
 358                 return;
 359
 360         local_irq_save(flags);
 361         sg_copy_from_buffer(mq->bounce_sg, mq->bounce_sg_len,
 362                 mq->bounce_buf, mq->sg[0].length);
 363         local_irq_restore(flags);
 364 }
 365