/*
 *  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/dma-mapping.h>

#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
#include <linux/sched/rt.h>
#include <uapi/linux/sched/types.h>

#include "queue.h"
#include "block.h"
#include "core.h"
#include "card.h"

/*
 * Prepare a MMC request. This just filters out odd stuff.
 */
int mmc_prep_request(struct request_queue *q, struct request *req)
{
	struct mmc_queue *mq = q->queuedata;

	if (mq && (mmc_card_removed(mq->card) || mmc_access_rpmb(mq)))
		return BLKPREP_KILL;

	req->rq_flags |= RQF_DONTPREP;

	return BLKPREP_OK;
}

static int mmc_queue_thread(void *d)
{
	struct mmc_queue *mq = d;
	struct request_queue *q = mq->queue;
	struct mmc_context_info *cntx = &mq->card->host->context_info;
	struct sched_param scheduler_params = {0};

	scheduler_params.sched_priority = 1;

	sched_setscheduler(current, SCHED_FIFO, &scheduler_params);

	current->flags |= PF_MEMALLOC;

	down(&mq->thread_sem);
	do {
		struct request *req;

		spin_lock_irq(q->queue_lock);
		set_current_state(TASK_INTERRUPTIBLE); /*lint !e446 !e666*/
		req = blk_fetch_request(q);
		mq->asleep = false;
		cntx->is_waiting_last_req = false;
		cntx->is_new_req = false;
		if (!req) {
			/*
			 * Dispatch queue is empty so set flags for
			 * mmc_request_fn() to wake us up.
			 */
			if (mq->qcnt)
				cntx->is_waiting_last_req = true;
			else
				mq->asleep = true;
		}
		spin_unlock_irq(q->queue_lock);

		if (req || mq->qcnt) {
			set_current_state(TASK_RUNNING); /*lint !e446 !e666*/
			mmc_blk_issue_rq(mq, req);
			cond_resched();
		} else {
			if (kthread_should_stop()) {
				set_current_state(TASK_RUNNING); /*lint !e446 !e666*/
				break;
			}
			up(&mq->thread_sem);
			schedule();
			down(&mq->thread_sem);
		}
	} 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_fn(struct request_queue *q)
{
	struct mmc_queue *mq = q->queuedata;
	struct request *req;
	struct mmc_context_info *cntx;

	if (!mq) {
		while ((req = blk_fetch_request(q)) != NULL) {
			req->rq_flags |= RQF_QUIET;
			__blk_end_request_all(req, BLK_STS_IOERR);
		}
		return;
	}

	cntx = &mq->card->host->context_info;

	if (cntx->is_waiting_last_req) {
		cntx->is_new_req = true;
		wake_up_interruptible(&cntx->wait);
	}

	if (mq->asleep)
		wake_up_process(mq->thread);
}

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;
}

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);
	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))
		queue_flag_set_unlocked(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
 */
int mmc_init_request(struct request_queue *q, struct request *req,
			    gfp_t gfp)
{
	struct mmc_queue_req *mq_rq = req_to_mmc_queue_req(req);
	struct mmc_queue *mq = q->queuedata;
	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;
}

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;
}

/**
 * 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, int area_type)
{
	struct mmc_host *host = card->host;
	u64 limit = BLK_BOUNCE_HIGH; /*lint !e501*/
	int ret = -ENOMEM;

	if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
		limit = (u64)dma_max_pfn(mmc_dev(host)) << PAGE_SHIFT;

	mq->card = card;
#ifdef CONFIG_MMC_CQ_HCI
	if (card->ext_csd.cmdq_mode_en
		&& (area_type == MMC_BLK_DATA_AREA_MAIN)) {
		ret = mmc_cmdq_init_queue(mq, card, lock, subname);
		return ret;
	}
#endif
	mq->queue = blk_alloc_queue(GFP_KERNEL);
	if (!mq->queue)
		return -ENOMEM;
	mq->queue->queue_lock = lock;
	mq->queue->request_fn = mmc_request_fn;
	mq->queue->init_rq_fn = mmc_init_request;
	mq->queue->exit_rq_fn = mmc_exit_request;
	mq->queue->cmd_size = sizeof(struct mmc_queue_req);
	mq->queue->queuedata = mq;
	mq->qcnt = 0;
	ret = blk_init_allocated_queue(mq->queue);
	if (ret) {
		blk_cleanup_queue(mq->queue);
		return ret;
	}

	blk_queue_prep_rq(mq->queue, mmc_prep_request);
	queue_flag_set_unlocked(QUEUE_FLAG_NONROT, mq->queue);
	queue_flag_clear_unlocked(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);
	blk_queue_max_segment_size(mq->queue, host->max_seg_size);

	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 cleanup_queue;
	}

	return 0;

cleanup_queue:
	blk_cleanup_queue(mq->queue);
	return ret;
}

void mmc_cleanup_queue(struct mmc_queue *mq)
{
	struct request_queue *q = mq->queue;
	unsigned long flags;

	/* 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);

	blk_cleanup_queue(q);
	mq->card = NULL;
}
EXPORT_SYMBOL(mmc_cleanup_queue);

int mmc_cmdq_queue_suspend(struct mmc_queue *mq,int wait)
{
	int rc = 0;
	int ret = 0;
	unsigned long flags;
	struct request *req = NULL;
	struct request_queue *q = mq->queue;
	struct mmc_host *host = mq->card->host;

	if (mq->suspended) {
		pr_err("%s: already in suspend status\n", __func__);
		goto out;
	}

	mq->suspended |= true;

	if (wait) {

		/*
		 * After blk_stop_queue is called, wait for all
		 * active_reqs to complete.
		 * Then wait for cmdq thread to exit before calling
		 * cmdq shutdown to avoid race between issuing
		 * requests and shutdown of cmdq.
		 */
		spin_lock_irqsave(q->queue_lock, flags);
		blk_stop_queue(q);
		spin_unlock_irqrestore(q->queue_lock, flags);

		if (host->cmdq_ctx.active_reqs) {
			ret = wait_for_completion_timeout(
					&mq->cmdq_shutdown_complete,
					msecs_to_jiffies(20000));
			if (ret)
				pr_err("%s: wait for cmdq shutdowan complete timeout\n",
						__func__);
		}
		kthread_stop(mq->thread);
		mq->cmdq_shutdown(mq);
	} else {
		spin_lock_irqsave(q->queue_lock, flags);
		blk_stop_queue(q);
		wake_up(&host->cmdq_ctx.wait);
		req = blk_peek_request(q);
		if (req || mq->cmdq_req_peeked ||
		    host->cmdq_ctx.active_reqs) {
			pr_err("%s: queue suspend fail, req:0x%pK"
				"req_peeked:0x%pK, active_reqs:0x%lx\n",
				__func__, req, mq->cmdq_req_peeked,
				host->cmdq_ctx.active_reqs);
			mq->suspended = false;
			blk_start_queue(q);
			rc = -EBUSY;
		}
		spin_unlock_irqrestore(q->queue_lock, flags);
	}

out:
	return rc;
}

/**
 * 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.
 */
int mmc_queue_suspend(struct mmc_queue *mq,int wait)
{
	struct request_queue *q = mq->queue;
	unsigned long flags;
	int rc = 0;

	/* cmdq process */
#ifdef CONFIG_MMC_CQ_HCI
	if (mq->card->cmdq_init && blk_queue_tagged(q)) {
		rc = mmc_cmdq_queue_suspend(mq, wait);
		return rc;
	}
#endif

	/* non cmdq process */
	if (!mq->suspended) {
		mq->suspended |= true;

		spin_lock_irqsave(q->queue_lock, flags);
		blk_stop_queue(q);
		spin_unlock_irqrestore(q->queue_lock, flags);

		rc = down_trylock(&mq->thread_sem);
		if (rc && !wait){
			pr_err("fail to down sem in mmc_queue_suspend");
			/*
			 * Failed to take the lock so better to abort the
			 * suspend because mmcqd thread is processing requests.
			 */
			mq->suspended = false;
			spin_lock_irqsave(q->queue_lock, flags);
			blk_start_queue(q);
			spin_unlock_irqrestore(q->queue_lock, flags);
			rc = -EBUSY;
		} else if (rc && wait) {
			down(&mq->thread_sem);
			rc = 0;
		}
	}

	return rc;
}

/**
 * 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->suspended) {
		mq->suspended = false;

		if (!(mq->card->cmdq_init && blk_queue_tagged(q)))
			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)
{
	struct request *req = mmc_queue_req_to_req(mqrq);

	return blk_rq_map_sg(mq->queue, req, mqrq->sg);
}
