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   1 /*
   2  *  linux/drivers/mmc/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
  17 #include <linux/mmc/card.h>
  18 #include <linux/mmc/host.h>
  19 #include "queue.h"
  20
  21 #define MMC_QUEUE_BOUNCESZ      65536
  22
  23 #define MMC_QUEUE_SUSPENDED     (1 << 0)
  24
  25 /*
  26  * Prepare a MMC request. This just filters out odd stuff.
  27  */
  28 static int mmc_prep_request(struct request_queue *q, struct request *req)
  29 {
  30         /*
  31          * We only like normal block requests.
  32          */
  33         if (!blk_fs_request(req) && !blk_pc_request(req)) {
  34                 blk_dump_rq_flags(req, "MMC bad request");
  35                 return BLKPREP_KILL;
  36         }
  37
  38         req->cmd_flags |= REQ_DONTPREP;
  39
  40         return BLKPREP_OK;
  41 }
  42
  43 static int mmc_queue_thread(void *d)
  44 {
  45         struct mmc_queue *mq = d;
  46         struct request_queue *q = mq->queue;
  47
  48         current->flags |= PF_MEMALLOC;
  49
  50         down(&mq->thread_sem);
  51         do {
  52                 struct request *req = NULL;
  53
  54                 spin_lock_irq(q->queue_lock);
  55                 set_current_state(TASK_INTERRUPTIBLE);
  56                 if (!blk_queue_plugged(q))
  57                         req = elv_next_request(q);
  58                 mq->req = req;
  59                 spin_unlock_irq(q->queue_lock);
  60
  61                 if (!req) {
  62                         if (kthread_should_stop()) {
  63                                 set_current_state(TASK_RUNNING);
  64                                 break;
  65                         }
  66                         up(&mq->thread_sem);
  67                         schedule();
  68                         down(&mq->thread_sem);
  69                         continue;
  70                 }
  71                 set_current_state(TASK_RUNNING);
  72
  73                 mq->issue_fn(mq, req);
  74         } while (1);
  75         up(&mq->thread_sem);
  76
  77         return 0;
  78 }
  79
  80 /*
  81  * Generic MMC request handler.  This is called for any queue on a
  82  * particular host.  When the host is not busy, we look for a request
  83  * on any queue on this host, and attempt to issue it.  This may
  84  * not be the queue we were asked to process.
  85  */
  86 static void mmc_request(request_queue_t *q)
  87 {
  88         struct mmc_queue *mq = q->queuedata;
  89         struct request *req;
  90         int ret;
  91
  92         if (!mq) {
  93                 printk(KERN_ERR "MMC: killing requests for dead queue\n");
  94                 while ((req = elv_next_request(q)) != NULL) {
  95                         do {
  96                                 ret = end_that_request_chunk(req, 0,
  97                                         req->current_nr_sectors << 9);
  98                         } while (ret);
  99                 }
 100                 return;
 101         }
 102
 103         if (!mq->req)
 104                 wake_up_process(mq->thread);
 105 }
 106
 107 /**
 108  * mmc_init_queue - initialise a queue structure.
 109  * @mq: mmc queue
 110  * @card: mmc card to attach this queue
 111  * @lock: queue lock
 112  *
 113  * Initialise a MMC card request queue.
 114  */
 115 int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card, spinlock_t *lock)
 116 {
 117         struct mmc_host *host = card->host;
 118         u64 limit = BLK_BOUNCE_HIGH;
 119         int ret;
 120         unsigned int bouncesz;
 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                 bouncesz = MMC_QUEUE_BOUNCESZ;
 138
 139                 if (bouncesz > host->max_req_size)
 140                         bouncesz = host->max_req_size;
 141                 if (bouncesz > host->max_seg_size)
 142                         bouncesz = host->max_seg_size;
 143
 144                 mq->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
 145                 if (!mq->bounce_buf) {
 146                         printk(KERN_WARNING "%s: unable to allocate "
 147                                 "bounce buffer\n", mmc_card_name(card));
 148                 } else {
 149                         blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_HIGH);
 150                         blk_queue_max_sectors(mq->queue, bouncesz / 512);
 151                         blk_queue_max_phys_segments(mq->queue, bouncesz / 512);
 152                         blk_queue_max_hw_segments(mq->queue, bouncesz / 512);
 153                         blk_queue_max_segment_size(mq->queue, bouncesz);
 154
 155                         mq->sg = kmalloc(sizeof(struct scatterlist),
 156                                 GFP_KERNEL);
 157                         if (!mq->sg) {
 158                                 ret = -ENOMEM;
 159                                 goto free_bounce_buf;
 160                         }
 161
 162                         mq->bounce_sg = kmalloc(sizeof(struct scatterlist) *
 163                                 bouncesz / 512, GFP_KERNEL);
 164                         if (!mq->bounce_sg) {
 165                                 ret = -ENOMEM;
 166                                 goto free_sg;
 167                         }
 168                 }
 169         }
 170 #endif
 171
 172         if (!mq->bounce_buf) {
 173                 blk_queue_bounce_limit(mq->queue, limit);
 174                 blk_queue_max_sectors(mq->queue, host->max_req_size / 512);
 175                 blk_queue_max_phys_segments(mq->queue, host->max_phys_segs);
 176                 blk_queue_max_hw_segments(mq->queue, host->max_hw_segs);
 177                 blk_queue_max_segment_size(mq->queue, host->max_seg_size);
 178
 179                 mq->sg = kmalloc(sizeof(struct scatterlist) *
 180                         host->max_phys_segs, GFP_KERNEL);
 181                 if (!mq->sg) {
 182                         ret = -ENOMEM;
 183                         goto cleanup_queue;
 184                 }
 185         }
 186
 187         init_MUTEX(&mq->thread_sem);
 188
 189         mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd");
 190         if (IS_ERR(mq->thread)) {
 191                 ret = PTR_ERR(mq->thread);
 192                 goto free_bounce_sg;
 193         }
 194
 195         return 0;
 196  free_bounce_sg:
 197         if (mq->bounce_sg)
 198                 kfree(mq->bounce_sg);
 199         mq->bounce_sg = NULL;
 200  free_sg:
 201         kfree(mq->sg);
 202         mq->sg = NULL;
 203  free_bounce_buf:
 204         if (mq->bounce_buf)
 205                 kfree(mq->bounce_buf);
 206         mq->bounce_buf = NULL;
 207  cleanup_queue:
 208         blk_cleanup_queue(mq->queue);
 209         return ret;
 210 }
 211
 212 void mmc_cleanup_queue(struct mmc_queue *mq)
 213 {
 214         request_queue_t *q = mq->queue;
 215         unsigned long flags;
 216
 217         /* Mark that we should start throwing out stragglers */
 218         spin_lock_irqsave(q->queue_lock, flags);
 219         q->queuedata = NULL;
 220         spin_unlock_irqrestore(q->queue_lock, flags);
 221
 222         /* Make sure the queue isn't suspended, as that will deadlock */
 223         mmc_queue_resume(mq);
 224
 225         /* Then terminate our worker thread */
 226         kthread_stop(mq->thread);
 227
 228         if (mq->bounce_sg)
 229                 kfree(mq->bounce_sg);
 230         mq->bounce_sg = NULL;
 231
 232         kfree(mq->sg);
 233         mq->sg = NULL;
 234
 235         if (mq->bounce_buf)
 236                 kfree(mq->bounce_buf);
 237         mq->bounce_buf = NULL;
 238
 239         blk_cleanup_queue(mq->queue);
 240
 241         mq->card = NULL;
 242 }
 243 EXPORT_SYMBOL(mmc_cleanup_queue);
 244
 245 /**
 246  * mmc_queue_suspend - suspend a MMC request queue
 247  * @mq: MMC queue to suspend
 248  *
 249  * Stop the block request queue, and wait for our thread to
 250  * complete any outstanding requests.  This ensures that we
 251  * won't suspend while a request is being processed.
 252  */
 253 void mmc_queue_suspend(struct mmc_queue *mq)
 254 {
 255         request_queue_t *q = mq->queue;
 256         unsigned long flags;
 257
 258         if (!(mq->flags & MMC_QUEUE_SUSPENDED)) {
 259                 mq->flags |= MMC_QUEUE_SUSPENDED;
 260
 261                 spin_lock_irqsave(q->queue_lock, flags);
 262                 blk_stop_queue(q);
 263                 spin_unlock_irqrestore(q->queue_lock, flags);
 264
 265                 down(&mq->thread_sem);
 266         }
 267 }
 268
 269 /**
 270  * mmc_queue_resume - resume a previously suspended MMC request queue
 271  * @mq: MMC queue to resume
 272  */
 273 void mmc_queue_resume(struct mmc_queue *mq)
 274 {
 275         request_queue_t *q = mq->queue;
 276         unsigned long flags;
 277
 278         if (mq->flags & MMC_QUEUE_SUSPENDED) {
 279                 mq->flags &= ~MMC_QUEUE_SUSPENDED;
 280
 281                 up(&mq->thread_sem);
 282
 283                 spin_lock_irqsave(q->queue_lock, flags);
 284                 blk_start_queue(q);
 285                 spin_unlock_irqrestore(q->queue_lock, flags);
 286         }
 287 }
 288
 289 static void copy_sg(struct scatterlist *dst, unsigned int dst_len,
 290         struct scatterlist *src, unsigned int src_len)
 291 {
 292         unsigned int chunk;
 293         char *dst_buf, *src_buf;
 294         unsigned int dst_size, src_size;
 295
 296         dst_buf = NULL;
 297         src_buf = NULL;
 298         dst_size = 0;
 299         src_size = 0;
 300
 301         while (src_len) {
 302                 BUG_ON(dst_len == 0);
 303
 304                 if (dst_size == 0) {
 305                         dst_buf = page_address(dst->page) + dst->offset;
 306                         dst_size = dst->length;
 307                 }
 308
 309                 if (src_size == 0) {
 310                         src_buf = page_address(src->page) + src->offset;
 311                         src_size = src->length;
 312                 }
 313
 314                 chunk = min(dst_size, src_size);
 315
 316                 memcpy(dst_buf, src_buf, chunk);
 317
 318                 dst_buf += chunk;
 319                 src_buf += chunk;
 320                 dst_size -= chunk;
 321                 src_size -= chunk;
 322
 323                 if (dst_size == 0) {
 324                         dst++;
 325                         dst_len--;
 326                 }
 327
 328                 if (src_size == 0) {
 329                         src++;
 330                         src_len--;
 331                 }
 332         }
 333 }
 334
 335 unsigned int mmc_queue_map_sg(struct mmc_queue *mq)
 336 {
 337         unsigned int sg_len;
 338
 339         if (!mq->bounce_buf)
 340                 return blk_rq_map_sg(mq->queue, mq->req, mq->sg);
 341
 342         BUG_ON(!mq->bounce_sg);
 343
 344         sg_len = blk_rq_map_sg(mq->queue, mq->req, mq->bounce_sg);
 345
 346         mq->bounce_sg_len = sg_len;
 347
 348         /*
 349          * Shortcut in the event we only get a single entry.
 350          */
 351         if (sg_len == 1) {
 352                 memcpy(mq->sg, mq->bounce_sg, sizeof(struct scatterlist));
 353                 return 1;
 354         }
 355
 356         mq->sg[0].page = virt_to_page(mq->bounce_buf);
 357         mq->sg[0].offset = offset_in_page(mq->bounce_buf);
 358         mq->sg[0].length = 0;
 359
 360         while (sg_len) {
 361                 mq->sg[0].length += mq->bounce_sg[sg_len - 1].length;
 362                 sg_len--;
 363         }
 364
 365         return 1;
 366 }
 367
 368 void mmc_queue_bounce_pre(struct mmc_queue *mq)
 369 {
 370         if (!mq->bounce_buf)
 371                 return;
 372
 373         if (mq->bounce_sg_len == 1)
 374                 return;
 375         if (rq_data_dir(mq->req) != WRITE)
 376                 return;
 377
 378         copy_sg(mq->sg, 1, mq->bounce_sg, mq->bounce_sg_len);
 379 }
 380
 381 void mmc_queue_bounce_post(struct mmc_queue *mq)
 382 {
 383         if (!mq->bounce_buf)
 384                 return;
 385
 386         if (mq->bounce_sg_len == 1)
 387                 return;
 388         if (rq_data_dir(mq->req) != READ)
 389                 return;
 390
 391         copy_sg(mq->bounce_sg, mq->bounce_sg_len, mq->sg, 1);
 392 }
 393