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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) && !blk_pc_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
 135 #ifdef CONFIG_MMC_BLOCK_BOUNCE
 136         if (host->max_hw_segs == 1) {
 137                 unsigned int bouncesz;
 138
 139                 bouncesz = MMC_QUEUE_BOUNCESZ;
 140
 141                 if (bouncesz > host->max_req_size)
 142                         bouncesz = host->max_req_size;
 143                 if (bouncesz > host->max_seg_size)
 144                         bouncesz = host->max_seg_size;
 145
 146                 mq->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
 147                 if (!mq->bounce_buf) {
 148                         printk(KERN_WARNING "%s: unable to allocate "
 149                                 "bounce buffer\n", mmc_card_name(card));
 150                 } else {
 151                         blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_HIGH);
 152                         blk_queue_max_sectors(mq->queue, bouncesz / 512);
 153                         blk_queue_max_phys_segments(mq->queue, bouncesz / 512);
 154                         blk_queue_max_hw_segments(mq->queue, bouncesz / 512);
 155                         blk_queue_max_segment_size(mq->queue, bouncesz);
 156
 157                         mq->sg = kmalloc(sizeof(struct scatterlist),
 158                                 GFP_KERNEL);
 159                         if (!mq->sg) {
 160                                 ret = -ENOMEM;
 161                                 goto cleanup_queue;
 162                         }
 163                         sg_init_table(mq->sg, 1);
 164
 165                         mq->bounce_sg = kmalloc(sizeof(struct scatterlist) *
 166                                 bouncesz / 512, GFP_KERNEL);
 167                         if (!mq->bounce_sg) {
 168                                 ret = -ENOMEM;
 169                                 goto cleanup_queue;
 170                         }
 171                         sg_init_table(mq->bounce_sg, bouncesz / 512);
 172                 }
 173         }
 174 #endif
 175
 176         if (!mq->bounce_buf) {
 177                 blk_queue_bounce_limit(mq->queue, limit);
 178                 blk_queue_max_sectors(mq->queue, host->max_req_size / 512);
 179                 blk_queue_max_phys_segments(mq->queue, host->max_phys_segs);
 180                 blk_queue_max_hw_segments(mq->queue, host->max_hw_segs);
 181                 blk_queue_max_segment_size(mq->queue, host->max_seg_size);
 182
 183                 mq->sg = kmalloc(sizeof(struct scatterlist) *
 184                         host->max_phys_segs, GFP_KERNEL);
 185                 if (!mq->sg) {
 186                         ret = -ENOMEM;
 187                         goto cleanup_queue;
 188                 }
 189                 sg_init_table(mq->sg, host->max_phys_segs);
 190         }
 191
 192         init_MUTEX(&mq->thread_sem);
 193
 194         mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd");
 195         if (IS_ERR(mq->thread)) {
 196                 ret = PTR_ERR(mq->thread);
 197                 goto free_bounce_sg;
 198         }
 199
 200         return 0;
 201  free_bounce_sg:
 202         if (mq->bounce_sg)
 203                 kfree(mq->bounce_sg);
 204         mq->bounce_sg = NULL;
 205  cleanup_queue:
 206         if (mq->sg)
 207                 kfree(mq->sg);
 208         mq->sg = NULL;
 209         if (mq->bounce_buf)
 210                 kfree(mq->bounce_buf);
 211         mq->bounce_buf = NULL;
 212         blk_cleanup_queue(mq->queue);
 213         return ret;
 214 }
 215
 216 void mmc_cleanup_queue(struct mmc_queue *mq)
 217 {
 218         struct request_queue *q = mq->queue;
 219         unsigned long flags;
 220
 221         /* Mark that we should start throwing out stragglers */
 222         spin_lock_irqsave(q->queue_lock, flags);
 223         q->queuedata = NULL;
 224         spin_unlock_irqrestore(q->queue_lock, 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         if (mq->bounce_sg)
 233                 kfree(mq->bounce_sg);
 234         mq->bounce_sg = NULL;
 235
 236         kfree(mq->sg);
 237         mq->sg = NULL;
 238
 239         if (mq->bounce_buf)
 240                 kfree(mq->bounce_buf);
 241         mq->bounce_buf = NULL;
 242
 243         blk_cleanup_queue(mq->queue);
 244
 245         mq->card = NULL;
 246 }
 247 EXPORT_SYMBOL(mmc_cleanup_queue);
 248
 249 /**
 250  * mmc_queue_suspend - suspend a MMC request queue
 251  * @mq: MMC queue to suspend
 252  *
 253  * Stop the block request queue, and wait for our thread to
 254  * complete any outstanding requests.  This ensures that we
 255  * won't suspend while a request is being processed.
 256  */
 257 void mmc_queue_suspend(struct mmc_queue *mq)
 258 {
 259         struct request_queue *q = mq->queue;
 260         unsigned long flags;
 261
 262         if (!(mq->flags & MMC_QUEUE_SUSPENDED)) {
 263                 mq->flags |= MMC_QUEUE_SUSPENDED;
 264
 265                 spin_lock_irqsave(q->queue_lock, flags);
 266                 blk_stop_queue(q);
 267                 spin_unlock_irqrestore(q->queue_lock, flags);
 268
 269                 down(&mq->thread_sem);
 270         }
 271 }
 272
 273 /**
 274  * mmc_queue_resume - resume a previously suspended MMC request queue
 275  * @mq: MMC queue to resume
 276  */
 277 void mmc_queue_resume(struct mmc_queue *mq)
 278 {
 279         struct request_queue *q = mq->queue;
 280         unsigned long flags;
 281
 282         if (mq->flags & MMC_QUEUE_SUSPENDED) {
 283                 mq->flags &= ~MMC_QUEUE_SUSPENDED;
 284
 285                 up(&mq->thread_sem);
 286
 287                 spin_lock_irqsave(q->queue_lock, flags);
 288                 blk_start_queue(q);
 289                 spin_unlock_irqrestore(q->queue_lock, flags);
 290         }
 291 }
 292
 293 static void copy_sg(struct scatterlist *dst, unsigned int dst_len,
 294         struct scatterlist *src, unsigned int src_len)
 295 {
 296         unsigned int chunk;
 297         char *dst_buf, *src_buf;
 298         unsigned int dst_size, src_size;
 299
 300         dst_buf = NULL;
 301         src_buf = NULL;
 302         dst_size = 0;
 303         src_size = 0;
 304
 305         while (src_len) {
 306                 BUG_ON(dst_len == 0);
 307
 308                 if (dst_size == 0) {
 309                         dst_buf = sg_virt(dst);
 310                         dst_size = dst->length;
 311                 }
 312
 313                 if (src_size == 0) {
 314                         src_buf = sg_virt(src);
 315                         src_size = src->length;
 316                 }
 317
 318                 chunk = min(dst_size, src_size);
 319
 320                 memcpy(dst_buf, src_buf, chunk);
 321
 322                 dst_buf += chunk;
 323                 src_buf += chunk;
 324                 dst_size -= chunk;
 325                 src_size -= chunk;
 326
 327                 if (dst_size == 0) {
 328                         dst++;
 329                         dst_len--;
 330                 }
 331
 332                 if (src_size == 0) {
 333                         src++;
 334                         src_len--;
 335                 }
 336         }
 337 }
 338
 339 unsigned int mmc_queue_map_sg(struct mmc_queue *mq)
 340 {
 341         unsigned int sg_len;
 342
 343         if (!mq->bounce_buf)
 344                 return blk_rq_map_sg(mq->queue, mq->req, mq->sg);
 345
 346         BUG_ON(!mq->bounce_sg);
 347
 348         sg_len = blk_rq_map_sg(mq->queue, mq->req, mq->bounce_sg);
 349
 350         mq->bounce_sg_len = sg_len;
 351
 352         /*
 353          * Shortcut in the event we only get a single entry.
 354          */
 355         if (sg_len == 1) {
 356                 memcpy(mq->sg, mq->bounce_sg, sizeof(struct scatterlist));
 357                 return 1;
 358         }
 359
 360         sg_init_one(mq->sg, mq->bounce_buf, 0);
 361
 362         while (sg_len) {
 363                 mq->sg[0].length += mq->bounce_sg[sg_len - 1].length;
 364                 sg_len--;
 365         }
 366
 367         return 1;
 368 }
 369
 370 void mmc_queue_bounce_pre(struct mmc_queue *mq)
 371 {
 372         if (!mq->bounce_buf)
 373                 return;
 374
 375         if (mq->bounce_sg_len == 1)
 376                 return;
 377         if (rq_data_dir(mq->req) != WRITE)
 378                 return;
 379
 380         copy_sg(mq->sg, 1, mq->bounce_sg, mq->bounce_sg_len);
 381 }
 382
 383 void mmc_queue_bounce_post(struct mmc_queue *mq)
 384 {
 385         if (!mq->bounce_buf)
 386                 return;
 387
 388         if (mq->bounce_sg_len == 1)
 389                 return;
 390         if (rq_data_dir(mq->req) != READ)
 391                 return;
 392
 393         copy_sg(mq->bounce_sg, mq->bounce_sg_len, mq->sg, 1);
 394 }
 395