text: /*
   *  linux/drivers/mmc/card/queue.c
   *
   *  Copyright (C) 2003 Russell King, All Rights Reserved.
   *  Copyright 2006-2007 Pierre Ossman
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   *
   */
  #include <linux/slab.h>
  #include <linux/module.h>
  #include <linux/blkdev.h>
  #include <linux/freezer.h>
  #include <linux/kthread.h>
  #include <linux/scatterlist.h>
  
  #include <linux/mmc/card.h>
  #include <linux/mmc/host.h>
  #include "queue.h"
  
  #define MMC_QUEUE_BOUNCESZ	65536
  
  #define MMC_QUEUE_SUSPENDED	(1 << 0)
  
  /*
   * Prepare a MMC request. This just filters out odd stuff.
   */
  static int mmc_prep_request(struct request_queue *q, struct request *req)
  {
  	struct mmc_queue *mq = q->queuedata;
  
  	/*
  	 * We only like normal block requests and discards.
  	 */
  	if (req->cmd_type != REQ_TYPE_FS && !(req->cmd_flags & REQ_DISCARD)) {
  		blk_dump_rq_flags(req, "MMC bad request");
  		return BLKPREP_KILL;
  	}
  
  	if (mq && mmc_card_removed(mq->card))
  		return BLKPREP_KILL;
  
  	req->cmd_flags |= REQ_DONTPREP;
  
  	return BLKPREP_OK;
  }
  
  static int mmc_queue_thread(void *d)
  {
  	struct mmc_queue *mq = d;
  	struct request_queue *q = mq->queue;
  
  	current->flags |= PF_MEMALLOC;
  
  	down(&mq->thread_sem);
  	do {
  		struct request *req = NULL;
  		struct mmc_queue_req *tmp;
  
  		spin_lock_irq(q->queue_lock);
  		set_current_state(TASK_INTERRUPTIBLE);
  		req = blk_fetch_request(q);
  		mq->mqrq_cur->req = req;
  		spin_unlock_irq(q->queue_lock);
  
  		if (req || mq->mqrq_prev->req) {
  			set_current_state(TASK_RUNNING);
  			mq->issue_fn(mq, req);
  		} else {
  			if (kthread_should_stop()) {
  				set_current_state(TASK_RUNNING);
  				break;
  			}
  			up(&mq->thread_sem);
  			schedule();
  			down(&mq->thread_sem);
  		}
  
  		/* Current request becomes previous request and vice versa. */
  		mq->mqrq_prev->brq.mrq.data = NULL;
  		mq->mqrq_prev->req = NULL;
  		tmp = mq->mqrq_prev;
  		mq->mqrq_prev = mq->mqrq_cur;
  		mq->mqrq_cur = tmp;
  	} while (1);
  	up(&mq->thread_sem);
  
  	return 0;
  }
  
  /*
   * Generic MMC request handler.  This is called for any queue on a
   * particular host.  When the host is not busy, we look for a request
   * on any queue on this host, and attempt to issue it.  This may
   * not be the queue we were asked to process.
   */
  static void mmc_request(struct request_queue *q)
  {
  	struct mmc_queue *mq = q->queuedata;
  	struct request *req;
  
  	if (!mq) {
  		while ((req = blk_fetch_request(q)) != NULL) {
  			req->cmd_flags |= REQ_QUIET;
  			__blk_end_request_all(req, -EIO);
  		}
  		return;
  	}
  
  	if (!mq->mqrq_cur->req && !mq->mqrq_prev->req)
  		wake_up_process(mq->thread);
  }
  
  static struct scatterlist *mmc_alloc_sg(int sg_len, int *err)
  {
  	struct scatterlist *sg;
  
  	sg = kmalloc(sizeof(struct scatterlist)*sg_len, GFP_KERNEL);
  	if (!sg)
  		*err = -ENOMEM;
  	else {
  		*err = 0;
  		sg_init_table(sg, sg_len);
  	}
  
  	return sg;
  }
  
  static void mmc_queue_setup_discard(struct request_queue *q,
  				    struct mmc_card *card)
  {
  	unsigned max_discard;
  
  	max_discard = mmc_calc_max_discard(card);
  	if (!max_discard)
  		return;
  
  	queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
  	q->limits.max_discard_sectors = max_discard;
  	if (card->erased_byte == 0 && !mmc_can_discard(card))
  		q->limits.discard_zeroes_data = 1;
  	q->limits.discard_granularity = card->pref_erase << 9;
  	/* granularity must not be greater than max. discard */
  	if (card->pref_erase > max_discard)
  		q->limits.discard_granularity = 0;
  	if (mmc_can_secure_erase_trim(card) || mmc_can_sanitize(card))
  		queue_flag_set_unlocked(QUEUE_FLAG_SECDISCARD, q);
  }
  
  /**
   * mmc_init_queue - initialise a queue structure.
   * @mq: mmc queue
   * @card: mmc card to attach this queue
   * @lock: queue lock
   * @subname: partition subname
   *
   * Initialise a MMC card request queue.
   */
  int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card,
  		   spinlock_t *lock, const char *subname)
  {
  	struct mmc_host *host = card->host;
  	u64 limit = BLK_BOUNCE_HIGH;
  	int ret;
  	struct mmc_queue_req *mqrq_cur = &mq->mqrq[0];
  	struct mmc_queue_req *mqrq_prev = &mq->mqrq[1];
  
  	if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
  		limit = *mmc_dev(host)->dma_mask;
  
  	mq->card = card;
  	mq->queue = blk_init_queue(mmc_request, lock);
  	if (!mq->queue)
  		return -ENOMEM;
  
  	memset(&mq->mqrq_cur, 0, sizeof(mq->mqrq_cur));
  	memset(&mq->mqrq_prev, 0, sizeof(mq->mqrq_prev));
  	mq->mqrq_cur = mqrq_cur;
  	mq->mqrq_prev = mqrq_prev;
  	mq->queue->queuedata = mq;
  
  	blk_queue_prep_rq(mq->queue, mmc_prep_request);
  	queue_flag_set_unlocked(QUEUE_FLAG_NONROT, mq->queue);
  	if (mmc_can_erase(card))
  		mmc_queue_setup_discard(mq->queue, card);
  
  #ifdef CONFIG_MMC_BLOCK_BOUNCE
  	if (host->max_segs == 1) {
  		unsigned int bouncesz;
  
  		bouncesz = MMC_QUEUE_BOUNCESZ;
  
  		if (bouncesz > host->max_req_size)
  			bouncesz = host->max_req_size;
  		if (bouncesz > host->max_seg_size)
  			bouncesz = host->max_seg_size;
  		if (bouncesz > (host->max_blk_count * 512))
  			bouncesz = host->max_blk_count * 512;
  
  		if (bouncesz > 512) {
  			mqrq_cur->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
  			if (!mqrq_cur->bounce_buf) {
  				pr_warning("%s: unable to "
  					"allocate bounce cur buffer\n",
  					mmc_card_name(card));
  			}
  			mqrq_prev->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
  			if (!mqrq_prev->bounce_buf) {
  				pr_warning("%s: unable to "
  					"allocate bounce prev buffer\n",
  					mmc_card_name(card));
  				kfree(mqrq_cur->bounce_buf);
  				mqrq_cur->bounce_buf = NULL;
  			}
  		}
  
  		if (mqrq_cur->bounce_buf && mqrq_prev->bounce_buf) {
  			blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_ANY);
  			blk_queue_max_hw_sectors(mq->queue, bouncesz / 512);
  			blk_queue_max_segments(mq->queue, bouncesz / 512);
  			blk_queue_max_segment_size(mq->queue, bouncesz);
  
  			mqrq_cur->sg = mmc_alloc_sg(1, &ret);
  			if (ret)
  				goto cleanup_queue;
  
  			mqrq_cur->bounce_sg =
  				mmc_alloc_sg(bouncesz / 512, &ret);
  			if (ret)
  				goto cleanup_queue;
  
  			mqrq_prev->sg = mmc_alloc_sg(1, &ret);
  			if (ret)
  				goto cleanup_queue;
  
  			mqrq_prev->bounce_sg =
  				mmc_alloc_sg(bouncesz / 512, &ret);
  			if (ret)
  				goto cleanup_queue;
  		}
  	}
  #endif
  
  	if (!mqrq_cur->bounce_buf && !mqrq_prev->bounce_buf) {
  		blk_queue_bounce_limit(mq->queue, limit);
  		blk_queue_max_hw_sectors(mq->queue,
  			min(host->max_blk_count, host->max_req_size / 512));
  		blk_queue_max_segments(mq->queue, host->max_segs);
  		blk_queue_max_segment_size(mq->queue, host->max_seg_size);
  
  		mqrq_cur->sg = mmc_alloc_sg(host->max_segs, &ret);
  		if (ret)
  			goto cleanup_queue;
  
  
  		mqrq_prev->sg = mmc_alloc_sg(host->max_segs, &ret);
  		if (ret)
  			goto cleanup_queue;
  	}
  
  	sema_init(&mq->thread_sem, 1);
  
  	mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd/%d%s",
  		host->index, subname ? subname : "");
  
  	if (IS_ERR(mq->thread)) {
  		ret = PTR_ERR(mq->thread);
  		goto free_bounce_sg;
  	}
  
  	return 0;
   free_bounce_sg:
  	kfree(mqrq_cur->bounce_sg);
  	mqrq_cur->bounce_sg = NULL;
  	kfree(mqrq_prev->bounce_sg);
  	mqrq_prev->bounce_sg = NULL;
  
   cleanup_queue:
  	kfree(mqrq_cur->sg);
  	mqrq_cur->sg = NULL;
  	kfree(mqrq_cur->bounce_buf);
  	mqrq_cur->bounce_buf = NULL;
  
  	kfree(mqrq_prev->sg);
  	mqrq_prev->sg = NULL;
  	kfree(mqrq_prev->bounce_buf);
  	mqrq_prev->bounce_buf = NULL;
  
  	blk_cleanup_queue(mq->queue);
  	return ret;
  }
  
  void mmc_cleanup_queue(struct mmc_queue *mq)
  {
  	struct request_queue *q = mq->queue;
  	unsigned long flags;
  	struct mmc_queue_req *mqrq_cur = mq->mqrq_cur;
  	struct mmc_queue_req *mqrq_prev = mq->mqrq_prev;
  
  	/* Make sure the queue isn't suspended, as that will deadlock */
  	mmc_queue_resume(mq);
  
  	/* Then terminate our worker thread */
  	kthread_stop(mq->thread);
  
  	/* Empty the queue */
  	spin_lock_irqsave(q->queue_lock, flags);
  	q->queuedata = NULL;
  	blk_start_queue(q);
  	spin_unlock_irqrestore(q->queue_lock, flags);
  
  	kfree(mqrq_cur->bounce_sg);
  	mqrq_cur->bounce_sg = NULL;
  
  	kfree(mqrq_cur->sg);
  	mqrq_cur->sg = NULL;
  
  	kfree(mqrq_cur->bounce_buf);
  	mqrq_cur->bounce_buf = NULL;
  
  	kfree(mqrq_prev->bounce_sg);
  	mqrq_prev->bounce_sg = NULL;
  
  	kfree(mqrq_prev->sg);
  	mqrq_prev->sg = NULL;
  
  	kfree(mqrq_prev->bounce_buf);
  	mqrq_prev->bounce_buf = NULL;
  
  	mq->card = NULL;
  }
  EXPORT_SYMBOL(mmc_cleanup_queue);
  
  /**
   * mmc_queue_suspend - suspend a MMC request queue
   * @mq: MMC queue to suspend
   *
   * Stop the block request queue, and wait for our thread to
   * complete any outstanding requests.  This ensures that we
   * won't suspend while a request is being processed.
   */
  void mmc_queue_suspend(struct mmc_queue *mq)
  {
  	struct request_queue *q = mq->queue;
  	unsigned long flags;
  
  	if (!(mq->flags & MMC_QUEUE_SUSPENDED)) {
  		mq->flags |= MMC_QUEUE_SUSPENDED;
  
  		spin_lock_irqsave(q->queue_lock, flags);
  		blk_stop_queue(q);
  		spin_unlock_irqrestore(q->queue_lock, flags);
  
  		down(&mq->thread_sem);
  	}
  }
  
  /**
   * mmc_queue_resume - resume a previously suspended MMC request queue
   * @mq: MMC queue to resume
   */
  void mmc_queue_resume(struct mmc_queue *mq)
  {
  	struct request_queue *q = mq->queue;
  	unsigned long flags;
  
  	if (mq->flags & MMC_QUEUE_SUSPENDED) {
  		mq->flags &= ~MMC_QUEUE_SUSPENDED;
  
  		up(&mq->thread_sem);
  
  		spin_lock_irqsave(q->queue_lock, flags);
  		blk_start_queue(q);
  		spin_unlock_irqrestore(q->queue_lock, flags);
  	}
  }
  
  /*
   * Prepare the sg list(s) to be handed of to the host driver
   */
  unsigned int mmc_queue_map_sg(struct mmc_queue *mq, struct mmc_queue_req *mqrq)
  {
  	unsigned int sg_len;
  	size_t buflen;
  	struct scatterlist *sg;
  	int i;
  
  	if (!mqrq->bounce_buf)
  		return blk_rq_map_sg(mq->queue, mqrq->req, mqrq->sg);
  
  	BUG_ON(!mqrq->bounce_sg);
  
  	sg_len = blk_rq_map_sg(mq->queue, mqrq->req, mqrq->bounce_sg);
  
  	mqrq->bounce_sg_len = sg_len;
  
  	buflen = 0;
  	for_each_sg(mqrq->bounce_sg, sg, sg_len, i)
  		buflen += sg->length;
  
  	sg_init_one(mqrq->sg, mqrq->bounce_buf, buflen);
  
  	return 1;
  }
  
  /*
   * If writing, bounce the data to the buffer before the request
   * is sent to the host driver
   */
  void mmc_queue_bounce_pre(struct mmc_queue_req *mqrq)
  {
  	if (!mqrq->bounce_buf)
  		return;
  
  	if (rq_data_dir(mqrq->req) != WRITE)
  		return;
  
  	sg_copy_to_buffer(mqrq->bounce_sg, mqrq->bounce_sg_len,
  		mqrq->bounce_buf, mqrq->sg[0].length);
  }
  
  /*
   * If reading, bounce the data from the buffer after the request
   * has been handled by the host driver
   */
  void mmc_queue_bounce_post(struct mmc_queue_req *mqrq)
  {
  	if (!mqrq->bounce_buf)
  		return;
  
  	if (rq_data_dir(mqrq->req) != READ)
  		return;
  
  	sg_copy_from_buffer(mqrq->bounce_sg, mqrq->bounce_sg_len,
  		mqrq->bounce_buf, mqrq->sg[0].length);
  }
  