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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 = elv_next_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         int ret;
  92
  93         if (!mq) {
  94                 printk(KERN_ERR "MMC: killing requests for dead queue\n");
  95                 while ((req = elv_next_request(q)) != NULL) {
  96                         do {
  97                                 ret = __blk_end_request(req, -EIO,
  98                                                         blk_rq_cur_bytes(req));
  99                         } while (ret);
 100                 }
 101                 return;
 102         }
 103
 104         if (!mq->req)
 105                 wake_up_process(mq->thread);
 106 }
 107
 108 /**
 109  * mmc_init_queue - initialise a queue structure.
 110  * @mq: mmc queue
 111  * @card: mmc card to attach this queue
 112  * @lock: queue lock
 113  *
 114  * Initialise a MMC card request queue.
 115  */
 116 int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card, spinlock_t *lock)
 117 {
 118         struct mmc_host *host = card->host;
 119         u64 limit = BLK_BOUNCE_HIGH;
 120         int ret;
 121
 122         if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
 123                 limit = *mmc_dev(host)->dma_mask;
 124
 125         mq->card = card;
 126         mq->queue = blk_init_queue(mmc_request, lock);
 127         if (!mq->queue)
 128                 return -ENOMEM;
 129
 130         mq->queue->queuedata = mq;
 131         mq->req = NULL;
 132
 133         blk_queue_prep_rq(mq->queue, mmc_prep_request);
 134         blk_queue_ordered(mq->queue, QUEUE_ORDERED_DRAIN, NULL);
 135
 136 #ifdef CONFIG_MMC_BLOCK_BOUNCE
 137         if (host->max_hw_segs == 1) {
 138                 unsigned int bouncesz;
 139
 140                 bouncesz = MMC_QUEUE_BOUNCESZ;
 141
 142                 if (bouncesz > host->max_req_size)
 143                         bouncesz = host->max_req_size;
 144                 if (bouncesz > host->max_seg_size)
 145                         bouncesz = host->max_seg_size;
 146                 if (bouncesz > (host->max_blk_count * 512))
 147                         bouncesz = host->max_blk_count * 512;
 148
 149                 if (bouncesz > 512) {
 150                         mq->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
 151                         if (!mq->bounce_buf) {
 152                                 printk(KERN_WARNING "%s: unable to "
 153                                         "allocate bounce buffer\n",
 154                                         mmc_card_name(card));
 155                         }
 156                 }
 157
 158                 if (mq->bounce_buf) {
 159                         blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_ANY);
 160                         blk_queue_max_sectors(mq->queue, bouncesz / 512);
 161                         blk_queue_max_phys_segments(mq->queue, bouncesz / 512);
 162                         blk_queue_max_hw_segments(mq->queue, bouncesz / 512);
 163                         blk_queue_max_segment_size(mq->queue, bouncesz);
 164
 165                         mq->sg = kmalloc(sizeof(struct scatterlist),
 166                                 GFP_KERNEL);
 167                         if (!mq->sg) {
 168                                 ret = -ENOMEM;
 169                                 goto cleanup_queue;
 170                         }
 171                         sg_init_table(mq->sg, 1);
 172
 173                         mq->bounce_sg = kmalloc(sizeof(struct scatterlist) *
 174                                 bouncesz / 512, GFP_KERNEL);
 175                         if (!mq->bounce_sg) {
 176                                 ret = -ENOMEM;
 177                                 goto cleanup_queue;
 178                         }
 179                         sg_init_table(mq->bounce_sg, bouncesz / 512);
 180                 }
 181         }
 182 #endif
 183
 184         if (!mq->bounce_buf) {
 185                 blk_queue_bounce_limit(mq->queue, limit);
 186                 blk_queue_max_sectors(mq->queue,
 187                         min(host->max_blk_count, host->max_req_size / 512));
 188                 blk_queue_max_phys_segments(mq->queue, host->max_phys_segs);
 189                 blk_queue_max_hw_segments(mq->queue, host->max_hw_segs);
 190                 blk_queue_max_segment_size(mq->queue, host->max_seg_size);
 191
 192                 mq->sg = kmalloc(sizeof(struct scatterlist) *
 193                         host->max_phys_segs, GFP_KERNEL);
 194                 if (!mq->sg) {
 195                         ret = -ENOMEM;
 196                         goto cleanup_queue;
 197                 }
 198                 sg_init_table(mq->sg, host->max_phys_segs);
 199         }
 200
 201         init_MUTEX(&mq->thread_sem);
 202
 203         mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd");
 204         if (IS_ERR(mq->thread)) {
 205                 ret = PTR_ERR(mq->thread);
 206                 goto free_bounce_sg;
 207         }
 208
 209         return 0;
 210  free_bounce_sg:
 211         if (mq->bounce_sg)
 212                 kfree(mq->bounce_sg);
 213         mq->bounce_sg = NULL;
 214  cleanup_queue:
 215         if (mq->sg)
 216                 kfree(mq->sg);
 217         mq->sg = NULL;
 218         if (mq->bounce_buf)
 219                 kfree(mq->bounce_buf);
 220         mq->bounce_buf = NULL;
 221         blk_cleanup_queue(mq->queue);
 222         return ret;
 223 }
 224
 225 void mmc_cleanup_queue(struct mmc_queue *mq)
 226 {
 227         struct request_queue *q = mq->queue;
 228         unsigned long flags;
 229
 230         /* Mark that we should start throwing out stragglers */
 231         spin_lock_irqsave(q->queue_lock, flags);
 232         q->queuedata = NULL;
 233         spin_unlock_irqrestore(q->queue_lock, flags);
 234
 235         /* Make sure the queue isn't suspended, as that will deadlock */
 236         mmc_queue_resume(mq);
 237
 238         /* Then terminate our worker thread */
 239         kthread_stop(mq->thread);
 240
 241         if (mq->bounce_sg)
 242                 kfree(mq->bounce_sg);
 243         mq->bounce_sg = NULL;
 244
 245         kfree(mq->sg);
 246         mq->sg = NULL;
 247
 248         if (mq->bounce_buf)
 249                 kfree(mq->bounce_buf);
 250         mq->bounce_buf = NULL;
 251
 252         blk_cleanup_queue(mq->queue);
 253
 254         mq->card = NULL;
 255 }
 256 EXPORT_SYMBOL(mmc_cleanup_queue);
 257
 258 /**
 259  * mmc_queue_suspend - suspend a MMC request queue
 260  * @mq: MMC queue to suspend
 261  *
 262  * Stop the block request queue, and wait for our thread to
 263  * complete any outstanding requests.  This ensures that we
 264  * won't suspend while a request is being processed.
 265  */
 266 void mmc_queue_suspend(struct mmc_queue *mq)
 267 {
 268         struct request_queue *q = mq->queue;
 269         unsigned long flags;
 270
 271         if (!(mq->flags & MMC_QUEUE_SUSPENDED)) {
 272                 mq->flags |= MMC_QUEUE_SUSPENDED;
 273
 274                 spin_lock_irqsave(q->queue_lock, flags);
 275                 blk_stop_queue(q);
 276                 spin_unlock_irqrestore(q->queue_lock, flags);
 277
 278                 down(&mq->thread_sem);
 279         }
 280 }
 281
 282 /**
 283  * mmc_queue_resume - resume a previously suspended MMC request queue
 284  * @mq: MMC queue to resume
 285  */
 286 void mmc_queue_resume(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                 up(&mq->thread_sem);
 295
 296                 spin_lock_irqsave(q->queue_lock, flags);
 297                 blk_start_queue(q);
 298                 spin_unlock_irqrestore(q->queue_lock, flags);
 299         }
 300 }
 301
 302 /*
 303  * Prepare the sg list(s) to be handed of to the host driver
 304  */
 305 unsigned int mmc_queue_map_sg(struct mmc_queue *mq)
 306 {
 307         unsigned int sg_len;
 308         size_t buflen;
 309         struct scatterlist *sg;
 310         int i;
 311
 312         if (!mq->bounce_buf)
 313                 return blk_rq_map_sg(mq->queue, mq->req, mq->sg);
 314
 315         BUG_ON(!mq->bounce_sg);
 316
 317         sg_len = blk_rq_map_sg(mq->queue, mq->req, mq->bounce_sg);
 318
 319         mq->bounce_sg_len = sg_len;
 320
 321         buflen = 0;
 322         for_each_sg(mq->bounce_sg, sg, sg_len, i)
 323                 buflen += sg->length;
 324
 325         sg_init_one(mq->sg, mq->bounce_buf, buflen);
 326
 327         return 1;
 328 }
 329
 330 /*
 331  * If writing, bounce the data to the buffer before the request
 332  * is sent to the host driver
 333  */
 334 void mmc_queue_bounce_pre(struct mmc_queue *mq)
 335 {
 336         unsigned long flags;
 337
 338         if (!mq->bounce_buf)
 339                 return;
 340
 341         if (rq_data_dir(mq->req) != WRITE)
 342                 return;
 343
 344         local_irq_save(flags);
 345         sg_copy_to_buffer(mq->bounce_sg, mq->bounce_sg_len,
 346                 mq->bounce_buf, mq->sg[0].length);
 347         local_irq_restore(flags);
 348 }
 349
 350 /*
 351  * If reading, bounce the data from the buffer after the request
 352  * has been handled by the host driver
 353  */
 354 void mmc_queue_bounce_post(struct mmc_queue *mq)
 355 {
 356         unsigned long flags;
 357
 358         if (!mq->bounce_buf)
 359                 return;
 360
 361         if (rq_data_dir(mq->req) != READ)
 362                 return;
 363
 364         local_irq_save(flags);
 365         sg_copy_from_buffer(mq->bounce_sg, mq->bounce_sg_len,
 366                 mq->bounce_buf, mq->sg[0].length);
 367         local_irq_restore(flags);
 368 }
 369