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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 = end_that_request_chunk(req, 0,
  98                                         req->current_nr_sectors << 9);
  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 = kzalloc(sizeof(struct scatterlist) *
 184                         host->max_phys_segs, GFP_KERNEL);
 185                 if (!mq->sg) {
 186                         ret = -ENOMEM;
 187                         goto cleanup_queue;
 188                 }
 189         }
 190
 191         init_MUTEX(&mq->thread_sem);
 192
 193         mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd");
 194         if (IS_ERR(mq->thread)) {
 195                 ret = PTR_ERR(mq->thread);
 196                 goto free_bounce_sg;
 197         }
 198
 199         return 0;
 200  free_bounce_sg:
 201         if (mq->bounce_sg)
 202                 kfree(mq->bounce_sg);
 203         mq->bounce_sg = NULL;
 204  cleanup_queue:
 205         if (mq->sg)
 206                 kfree(mq->sg);
 207         mq->sg = NULL;
 208         if (mq->bounce_buf)
 209                 kfree(mq->bounce_buf);
 210         mq->bounce_buf = NULL;
 211         blk_cleanup_queue(mq->queue);
 212         return ret;
 213 }
 214
 215 void mmc_cleanup_queue(struct mmc_queue *mq)
 216 {
 217         struct request_queue *q = mq->queue;
 218         unsigned long flags;
 219
 220         /* Mark that we should start throwing out stragglers */
 221         spin_lock_irqsave(q->queue_lock, flags);
 222         q->queuedata = NULL;
 223         spin_unlock_irqrestore(q->queue_lock, flags);
 224
 225         /* Make sure the queue isn't suspended, as that will deadlock */
 226         mmc_queue_resume(mq);
 227
 228         /* Then terminate our worker thread */
 229         kthread_stop(mq->thread);
 230
 231         if (mq->bounce_sg)
 232                 kfree(mq->bounce_sg);
 233         mq->bounce_sg = NULL;
 234
 235         kfree(mq->sg);
 236         mq->sg = NULL;
 237
 238         if (mq->bounce_buf)
 239                 kfree(mq->bounce_buf);
 240         mq->bounce_buf = NULL;
 241
 242         blk_cleanup_queue(mq->queue);
 243
 244         mq->card = NULL;
 245 }
 246 EXPORT_SYMBOL(mmc_cleanup_queue);
 247
 248 /**
 249  * mmc_queue_suspend - suspend a MMC request queue
 250  * @mq: MMC queue to suspend
 251  *
 252  * Stop the block request queue, and wait for our thread to
 253  * complete any outstanding requests.  This ensures that we
 254  * won't suspend while a request is being processed.
 255  */
 256 void mmc_queue_suspend(struct mmc_queue *mq)
 257 {
 258         struct request_queue *q = mq->queue;
 259         unsigned long flags;
 260
 261         if (!(mq->flags & MMC_QUEUE_SUSPENDED)) {
 262                 mq->flags |= MMC_QUEUE_SUSPENDED;
 263
 264                 spin_lock_irqsave(q->queue_lock, flags);
 265                 blk_stop_queue(q);
 266                 spin_unlock_irqrestore(q->queue_lock, flags);
 267
 268                 down(&mq->thread_sem);
 269         }
 270 }
 271
 272 /**
 273  * mmc_queue_resume - resume a previously suspended MMC request queue
 274  * @mq: MMC queue to resume
 275  */
 276 void mmc_queue_resume(struct mmc_queue *mq)
 277 {
 278         struct request_queue *q = mq->queue;
 279         unsigned long flags;
 280
 281         if (mq->flags & MMC_QUEUE_SUSPENDED) {
 282                 mq->flags &= ~MMC_QUEUE_SUSPENDED;
 283
 284                 up(&mq->thread_sem);
 285
 286                 spin_lock_irqsave(q->queue_lock, flags);
 287                 blk_start_queue(q);
 288                 spin_unlock_irqrestore(q->queue_lock, flags);
 289         }
 290 }
 291
 292 static void copy_sg(struct scatterlist *dst, unsigned int dst_len,
 293         struct scatterlist *src, unsigned int src_len)
 294 {
 295         unsigned int chunk;
 296         char *dst_buf, *src_buf;
 297         unsigned int dst_size, src_size;
 298
 299         dst_buf = NULL;
 300         src_buf = NULL;
 301         dst_size = 0;
 302         src_size = 0;
 303
 304         while (src_len) {
 305                 BUG_ON(dst_len == 0);
 306
 307                 if (dst_size == 0) {
 308                         dst_buf = sg_virt(dst);
 309                         dst_size = dst->length;
 310                 }
 311
 312                 if (src_size == 0) {
 313                         src_buf = sg_virt(dst);
 314                         src_size = src->length;
 315                 }
 316
 317                 chunk = min(dst_size, src_size);
 318
 319                 memcpy(dst_buf, src_buf, chunk);
 320
 321                 dst_buf += chunk;
 322                 src_buf += chunk;
 323                 dst_size -= chunk;
 324                 src_size -= chunk;
 325
 326                 if (dst_size == 0) {
 327                         dst++;
 328                         dst_len--;
 329                 }
 330
 331                 if (src_size == 0) {
 332                         src++;
 333                         src_len--;
 334                 }
 335         }
 336 }
 337
 338 unsigned int mmc_queue_map_sg(struct mmc_queue *mq)
 339 {
 340         unsigned int sg_len;
 341
 342         if (!mq->bounce_buf)
 343                 return blk_rq_map_sg(mq->queue, mq->req, mq->sg);
 344
 345         BUG_ON(!mq->bounce_sg);
 346
 347         sg_len = blk_rq_map_sg(mq->queue, mq->req, mq->bounce_sg);
 348
 349         mq->bounce_sg_len = sg_len;
 350
 351         /*
 352          * Shortcut in the event we only get a single entry.
 353          */
 354         if (sg_len == 1) {
 355                 memcpy(mq->sg, mq->bounce_sg, sizeof(struct scatterlist));
 356                 return 1;
 357         }
 358
 359         sg_init_one(mq->sg, mq->bounce_buf, 0);
 360
 361         while (sg_len) {
 362                 mq->sg[0].length += mq->bounce_sg[sg_len - 1].length;
 363                 sg_len--;
 364         }
 365
 366         return 1;
 367 }
 368
 369 void mmc_queue_bounce_pre(struct mmc_queue *mq)
 370 {
 371         if (!mq->bounce_buf)
 372                 return;
 373
 374         if (mq->bounce_sg_len == 1)
 375                 return;
 376         if (rq_data_dir(mq->req) != WRITE)
 377                 return;
 378
 379         copy_sg(mq->sg, 1, mq->bounce_sg, mq->bounce_sg_len);
 380 }
 381
 382 void mmc_queue_bounce_post(struct mmc_queue *mq)
 383 {
 384         if (!mq->bounce_buf)
 385                 return;
 386
 387         if (mq->bounce_sg_len == 1)
 388                 return;
 389         if (rq_data_dir(mq->req) != READ)
 390                 return;
 391
 392         copy_sg(mq->bounce_sg, mq->bounce_sg_len, mq->sg, 1);
 393 }
 394