text: // SPDX-License-Identifier: GPL-2.0-only
  /*
   *  Copyright (C) 2003 Russell King, All Rights Reserved.
   *  Copyright 2006-2007 Pierre Ossman
   */
  #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/dma-mapping.h>
  
  #include <linux/mmc/card.h>
  #include <linux/mmc/host.h>
  
  #include "queue.h"
  #include "block.h"
  #include "core.h"
  #include "card.h"
  #include "host.h"
  
  static inline bool mmc_cqe_dcmd_busy(struct mmc_queue *mq)
  {
  	/* Allow only 1 DCMD at a time */
  	return mq->in_flight[MMC_ISSUE_DCMD];
  }
  
  void mmc_cqe_check_busy(struct mmc_queue *mq)
  {
  	if ((mq->cqe_busy & MMC_CQE_DCMD_BUSY) && !mmc_cqe_dcmd_busy(mq))
  		mq->cqe_busy &= ~MMC_CQE_DCMD_BUSY;
  
  	mq->cqe_busy &= ~MMC_CQE_QUEUE_FULL;
  }
  
  static inline bool mmc_cqe_can_dcmd(struct mmc_host *host)
  {
  	return host->caps2 & MMC_CAP2_CQE_DCMD;
  }
  
  static enum mmc_issue_type mmc_cqe_issue_type(struct mmc_host *host,
  					      struct request *req)
  {
  	switch (req_op(req)) {
  	case REQ_OP_DRV_IN:
  	case REQ_OP_DRV_OUT:
  	case REQ_OP_DISCARD:
  	case REQ_OP_SECURE_ERASE:
  		return MMC_ISSUE_SYNC;
  	case REQ_OP_FLUSH:
  		return mmc_cqe_can_dcmd(host) ? MMC_ISSUE_DCMD : MMC_ISSUE_SYNC;
  	default:
  		return MMC_ISSUE_ASYNC;
  	}
  }
  
  enum mmc_issue_type mmc_issue_type(struct mmc_queue *mq, struct request *req)
  {
  	struct mmc_host *host = mq->card->host;
  
  	if (mq->use_cqe)
  		return mmc_cqe_issue_type(host, req);
  
  	if (req_op(req) == REQ_OP_READ || req_op(req) == REQ_OP_WRITE)
  		return MMC_ISSUE_ASYNC;
  
  	return MMC_ISSUE_SYNC;
  }
  
  static void __mmc_cqe_recovery_notifier(struct mmc_queue *mq)
  {
  	if (!mq->recovery_needed) {
  		mq->recovery_needed = true;
  		schedule_work(&mq->recovery_work);
  	}
  }
  
  void mmc_cqe_recovery_notifier(struct mmc_request *mrq)
  {
  	struct mmc_queue_req *mqrq = container_of(mrq, struct mmc_queue_req,
  						  brq.mrq);
  	struct request *req = mmc_queue_req_to_req(mqrq);
  	struct request_queue *q = req->q;
  	struct mmc_queue *mq = q->queuedata;
  	unsigned long flags;
  
  	spin_lock_irqsave(&mq->lock, flags);
  	__mmc_cqe_recovery_notifier(mq);
  	spin_unlock_irqrestore(&mq->lock, flags);
  }
  
  static enum blk_eh_timer_return mmc_cqe_timed_out(struct request *req)
  {
  	struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
  	struct mmc_request *mrq = &mqrq->brq.mrq;
  	struct mmc_queue *mq = req->q->queuedata;
  	struct mmc_host *host = mq->card->host;
  	enum mmc_issue_type issue_type = mmc_issue_type(mq, req);
  	bool recovery_needed = false;
  
  	switch (issue_type) {
  	case MMC_ISSUE_ASYNC:
  	case MMC_ISSUE_DCMD:
  		if (host->cqe_ops->cqe_timeout(host, mrq, &recovery_needed)) {
  			if (recovery_needed)
  				__mmc_cqe_recovery_notifier(mq);
  			return BLK_EH_RESET_TIMER;
  		}
  		/* No timeout (XXX: huh? comment doesn't make much sense) */
  		blk_mq_complete_request(req);
  		return BLK_EH_DONE;
  	default:
  		/* Timeout is handled by mmc core */
  		return BLK_EH_RESET_TIMER;
  	}
  }
  
  static enum blk_eh_timer_return mmc_mq_timed_out(struct request *req,
  						 bool reserved)
  {
  	struct request_queue *q = req->q;
  	struct mmc_queue *mq = q->queuedata;
  	unsigned long flags;
  	int ret;
  
  	spin_lock_irqsave(&mq->lock, flags);
  
  	if (mq->recovery_needed || !mq->use_cqe)
  		ret = BLK_EH_RESET_TIMER;
  	else
  		ret = mmc_cqe_timed_out(req);
  
  	spin_unlock_irqrestore(&mq->lock, flags);
  
  	return ret;
  }
  
  static void mmc_mq_recovery_handler(struct work_struct *work)
  {
  	struct mmc_queue *mq = container_of(work, struct mmc_queue,
  					    recovery_work);
  	struct request_queue *q = mq->queue;
  
  	mmc_get_card(mq->card, &mq->ctx);
  
  	mq->in_recovery = true;
  
  	if (mq->use_cqe)
  		mmc_blk_cqe_recovery(mq);
  	else
  		mmc_blk_mq_recovery(mq);
  
  	mq->in_recovery = false;
  
  	spin_lock_irq(&mq->lock);
  	mq->recovery_needed = false;
  	spin_unlock_irq(&mq->lock);
  
  	mmc_put_card(mq->card, &mq->ctx);
  
  	blk_mq_run_hw_queues(q, true);
  }
  
  static struct scatterlist *mmc_alloc_sg(int sg_len, gfp_t gfp)
  {
  	struct scatterlist *sg;
  
  	sg = kmalloc_array(sg_len, sizeof(*sg), gfp);
  	if (sg)
  		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;
  
  	blk_queue_flag_set(QUEUE_FLAG_DISCARD, q);
  	blk_queue_max_discard_sectors(q, max_discard);
  	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))
  		blk_queue_flag_set(QUEUE_FLAG_SECERASE, q);
  }
  
  /**
   * mmc_init_request() - initialize the MMC-specific per-request data
   * @q: the request queue
   * @req: the request
   * @gfp: memory allocation policy
   */
  static int __mmc_init_request(struct mmc_queue *mq, struct request *req,
  			      gfp_t gfp)
  {
  	struct mmc_queue_req *mq_rq = req_to_mmc_queue_req(req);
  	struct mmc_card *card = mq->card;
  	struct mmc_host *host = card->host;
  
  	mq_rq->sg = mmc_alloc_sg(host->max_segs, gfp);
  	if (!mq_rq->sg)
  		return -ENOMEM;
  
  	return 0;
  }
  
  static void mmc_exit_request(struct request_queue *q, struct request *req)
  {
  	struct mmc_queue_req *mq_rq = req_to_mmc_queue_req(req);
  
  	kfree(mq_rq->sg);
  	mq_rq->sg = NULL;
  }
  
  static int mmc_mq_init_request(struct blk_mq_tag_set *set, struct request *req,
  			       unsigned int hctx_idx, unsigned int numa_node)
  {
  	return __mmc_init_request(set->driver_data, req, GFP_KERNEL);
  }
  
  static void mmc_mq_exit_request(struct blk_mq_tag_set *set, struct request *req,
  				unsigned int hctx_idx)
  {
  	struct mmc_queue *mq = set->driver_data;
  
  	mmc_exit_request(mq->queue, req);
  }
  
  static blk_status_t mmc_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
  				    const struct blk_mq_queue_data *bd)
  {
  	struct request *req = bd->rq;
  	struct request_queue *q = req->q;
  	struct mmc_queue *mq = q->queuedata;
  	struct mmc_card *card = mq->card;
  	struct mmc_host *host = card->host;
  	enum mmc_issue_type issue_type;
  	enum mmc_issued issued;
  	bool get_card, cqe_retune_ok;
  	int ret;
  
  	if (mmc_card_removed(mq->card)) {
  		req->rq_flags |= RQF_QUIET;
  		return BLK_STS_IOERR;
  	}
  
  	issue_type = mmc_issue_type(mq, req);
  
  	spin_lock_irq(&mq->lock);
  
  	if (mq->recovery_needed || mq->busy) {
  		spin_unlock_irq(&mq->lock);
  		return BLK_STS_RESOURCE;
  	}
  
  	switch (issue_type) {
  	case MMC_ISSUE_DCMD:
  		if (mmc_cqe_dcmd_busy(mq)) {
  			mq->cqe_busy |= MMC_CQE_DCMD_BUSY;
  			spin_unlock_irq(&mq->lock);
  			return BLK_STS_RESOURCE;
  		}
  		break;
  	case MMC_ISSUE_ASYNC:
  		break;
  	default:
  		/*
  		 * Timeouts are handled by mmc core, and we don't have a host
  		 * API to abort requests, so we can't handle the timeout anyway.
  		 * However, when the timeout happens, blk_mq_complete_request()
  		 * no longer works (to stop the request disappearing under us).
  		 * To avoid racing with that, set a large timeout.
  		 */
  		req->timeout = 600 * HZ;
  		break;
  	}
  
  	/* Parallel dispatch of requests is not supported at the moment */
  	mq->busy = true;
  
  	mq->in_flight[issue_type] += 1;
  	get_card = (mmc_tot_in_flight(mq) == 1);
  	cqe_retune_ok = (mmc_cqe_qcnt(mq) == 1);
  
  	spin_unlock_irq(&mq->lock);
  
  	if (!(req->rq_flags & RQF_DONTPREP)) {
  		req_to_mmc_queue_req(req)->retries = 0;
  		req->rq_flags |= RQF_DONTPREP;
  	}
  
  	if (get_card)
  		mmc_get_card(card, &mq->ctx);
  
  	if (mq->use_cqe) {
  		host->retune_now = host->need_retune && cqe_retune_ok &&
  				   !host->hold_retune;
  	}
  
  	blk_mq_start_request(req);
  
  	issued = mmc_blk_mq_issue_rq(mq, req);
  
  	switch (issued) {
  	case MMC_REQ_BUSY:
  		ret = BLK_STS_RESOURCE;
  		break;
  	case MMC_REQ_FAILED_TO_START:
  		ret = BLK_STS_IOERR;
  		break;
  	default:
  		ret = BLK_STS_OK;
  		break;
  	}
  
  	if (issued != MMC_REQ_STARTED) {
  		bool put_card = false;
  
  		spin_lock_irq(&mq->lock);
  		mq->in_flight[issue_type] -= 1;
  		if (mmc_tot_in_flight(mq) == 0)
  			put_card = true;
  		mq->busy = false;
  		spin_unlock_irq(&mq->lock);
  		if (put_card)
  			mmc_put_card(card, &mq->ctx);
  	} else {
  		WRITE_ONCE(mq->busy, false);
  	}
  
  	return ret;
  }
  
  static const struct blk_mq_ops mmc_mq_ops = {
  	.queue_rq	= mmc_mq_queue_rq,
  	.init_request	= mmc_mq_init_request,
  	.exit_request	= mmc_mq_exit_request,
  	.complete	= mmc_blk_mq_complete,
  	.timeout	= mmc_mq_timed_out,
  };
  
  static void mmc_setup_queue(struct mmc_queue *mq, struct mmc_card *card)
  {
  	struct mmc_host *host = card->host;
  	u64 limit = BLK_BOUNCE_HIGH;
  	unsigned block_size = 512;
  
  	if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
  		limit = (u64)dma_max_pfn(mmc_dev(host)) << PAGE_SHIFT;
  
  	blk_queue_flag_set(QUEUE_FLAG_NONROT, mq->queue);
  	blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, mq->queue);
  	if (mmc_can_erase(card))
  		mmc_queue_setup_discard(mq->queue, card);
  
  	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);
  
  	if (mmc_card_mmc(card))
  		block_size = card->ext_csd.data_sector_size;
  
  	blk_queue_logical_block_size(mq->queue, block_size);
  	blk_queue_max_segment_size(mq->queue,
  			round_down(host->max_seg_size, block_size));
  
  	dma_set_max_seg_size(mmc_dev(host), queue_max_segment_size(mq->queue));
  
  	INIT_WORK(&mq->recovery_work, mmc_mq_recovery_handler);
  	INIT_WORK(&mq->complete_work, mmc_blk_mq_complete_work);
  
  	mutex_init(&mq->complete_lock);
  
  	init_waitqueue_head(&mq->wait);
  }
  
  /* Set queue depth to get a reasonable value for q->nr_requests */
  #define MMC_QUEUE_DEPTH 64
  
  /**
   * mmc_init_queue - initialise a queue structure.
   * @mq: mmc queue
   * @card: mmc card to attach this queue
   *
   * Initialise a MMC card request queue.
   */
  int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card)
  {
  	struct mmc_host *host = card->host;
  	int ret;
  
  	mq->card = card;
  	mq->use_cqe = host->cqe_enabled;
  	
  	spin_lock_init(&mq->lock);
  
  	memset(&mq->tag_set, 0, sizeof(mq->tag_set));
  	mq->tag_set.ops = &mmc_mq_ops;
  	/*
  	 * The queue depth for CQE must match the hardware because the request
  	 * tag is used to index the hardware queue.
  	 */
  	if (mq->use_cqe)
  		mq->tag_set.queue_depth =
  			min_t(int, card->ext_csd.cmdq_depth, host->cqe_qdepth);
  	else
  		mq->tag_set.queue_depth = MMC_QUEUE_DEPTH;
  	mq->tag_set.numa_node = NUMA_NO_NODE;
  	mq->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_BLOCKING;
  	mq->tag_set.nr_hw_queues = 1;
  	mq->tag_set.cmd_size = sizeof(struct mmc_queue_req);
  	mq->tag_set.driver_data = mq;
  
  	ret = blk_mq_alloc_tag_set(&mq->tag_set);
  	if (ret)
  		return ret;
  
  	mq->queue = blk_mq_init_queue(&mq->tag_set);
  	if (IS_ERR(mq->queue)) {
  		ret = PTR_ERR(mq->queue);
  		goto free_tag_set;
  	}
  
  	mq->queue->queuedata = mq;
  	blk_queue_rq_timeout(mq->queue, 60 * HZ);
  
  	mmc_setup_queue(mq, card);
  	return 0;
  
  free_tag_set:
  	blk_mq_free_tag_set(&mq->tag_set);
  	return ret;
  }
  
  void mmc_queue_suspend(struct mmc_queue *mq)
  {
  	blk_mq_quiesce_queue(mq->queue);
  
  	/*
  	 * The host remains claimed while there are outstanding requests, so
  	 * simply claiming and releasing here ensures there are none.
  	 */
  	mmc_claim_host(mq->card->host);
  	mmc_release_host(mq->card->host);
  }
  
  void mmc_queue_resume(struct mmc_queue *mq)
  {
  	blk_mq_unquiesce_queue(mq->queue);
  }
  
  void mmc_cleanup_queue(struct mmc_queue *mq)
  {
  	struct request_queue *q = mq->queue;
  
  	/*
  	 * The legacy code handled the possibility of being suspended,
  	 * so do that here too.
  	 */
  	if (blk_queue_quiesced(q))
  		blk_mq_unquiesce_queue(q);
  
  	blk_cleanup_queue(q);
  	blk_mq_free_tag_set(&mq->tag_set);
  
  	/*
  	 * A request can be completed before the next request, potentially
  	 * leaving a complete_work with nothing to do. Such a work item might
  	 * still be queued at this point. Flush it.
  	 */
  	flush_work(&mq->complete_work);
  
  	mq->card = NULL;
  }
  
  /*
   * 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)
  {
  	struct request *req = mmc_queue_req_to_req(mqrq);
  
  	return blk_rq_map_sg(mq->queue, req, mqrq->sg);
  }
  