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Commit 027f28b7 authored by Xiang Wang's avatar Xiang Wang Committed by Vinod Koul
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dma: mmp_pdma: add protect when alloc/free phy channels 



In mmp pdma, phy channels are allocated/freed dynamically
and frequently. But no proper protection is added.
Conflict will happen when multi-users are requesting phy
channels at the same time. Use spinlock to protect.

Signed-off-by: default avatarXiang Wang <wangx@marvell.com>
Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
parent 337ae47c

drivers/dma/mmp_pdma.c

+26 −16
Original line number Diff line number Diff line
@@ -121,6 +121,7 @@ struct mmp_pdma_device { 
	struct device			*dev;

	struct dma_device		device;

	struct mmp_pdma_phy		*phy;

	spinlock_t phy_lock; /* protect alloc/free phy channels */

};



#define tx_to_mmp_pdma_desc(tx) container_of(tx, struct mmp_pdma_desc_sw, async_tx)
@@ -219,6 +220,7 @@ static struct mmp_pdma_phy *lookup_phy(struct mmp_pdma_chan *pchan) 
	int prio, i;

	struct mmp_pdma_device *pdev = to_mmp_pdma_dev(pchan->chan.device);

	struct mmp_pdma_phy *phy;

	unsigned long flags;



	/*

	 * dma channel priorities
@@ -227,6 +229,8 @@ static struct mmp_pdma_phy *lookup_phy(struct mmp_pdma_chan *pchan) 
	 * ch 8 - 11, 24 - 27  <--> (2)

	 * ch 12 - 15, 28 - 31  <--> (3)

	 */



	spin_lock_irqsave(&pdev->phy_lock, flags);

	for (prio = 0; prio <= (((pdev->dma_channels - 1) & 0xf) >> 2); prio++) {

		for (i = 0; i < pdev->dma_channels; i++) {

			if (prio != ((i & 0xf) >> 2))
@@ -234,14 +238,30 @@ static struct mmp_pdma_phy *lookup_phy(struct mmp_pdma_chan *pchan) 
			phy = &pdev->phy[i];

			if (!phy->vchan) {

				phy->vchan = pchan;

				spin_unlock_irqrestore(&pdev->phy_lock, flags);

				return phy;

			}

		}

	}



	spin_unlock_irqrestore(&pdev->phy_lock, flags);

	return NULL;

}



static void mmp_pdma_free_phy(struct mmp_pdma_chan *pchan)

{

	struct mmp_pdma_device *pdev = to_mmp_pdma_dev(pchan->chan.device);

	unsigned long flags;



	if (!pchan->phy)

		return;



	spin_lock_irqsave(&pdev->phy_lock, flags);

	pchan->phy->vchan = NULL;

	pchan->phy = NULL;

	spin_unlock_irqrestore(&pdev->phy_lock, flags);

}



/* desc->tx_list ==> pending list */

static void append_pending_queue(struct mmp_pdma_chan *chan,

					struct mmp_pdma_desc_sw *desc)
@@ -277,10 +297,7 @@ static void start_pending_queue(struct mmp_pdma_chan *chan) 


	if (list_empty(&chan->chain_pending)) {

		/* chance to re-fetch phy channel with higher prio */

		if (chan->phy) {

			chan->phy->vchan = NULL;

			chan->phy = NULL;

		}

		mmp_pdma_free_phy(chan);

		dev_dbg(chan->dev, "no pending list\n");

		return;

	}
@@ -377,10 +394,7 @@ static int mmp_pdma_alloc_chan_resources(struct dma_chan *dchan) 
		dev_err(chan->dev, "unable to allocate descriptor pool\n");

		return -ENOMEM;

	}

	if (chan->phy) {

		chan->phy->vchan = NULL;

		chan->phy = NULL;

	}

	mmp_pdma_free_phy(chan);

	chan->idle = true;

	chan->dev_addr = 0;

	return 1;
@@ -411,10 +425,7 @@ static void mmp_pdma_free_chan_resources(struct dma_chan *dchan) 
	chan->desc_pool = NULL;

	chan->idle = true;

	chan->dev_addr = 0;

	if (chan->phy) {

		chan->phy->vchan = NULL;

		chan->phy = NULL;

	}

	mmp_pdma_free_phy(chan);

	return;

}
@@ -581,10 +592,7 @@ static int mmp_pdma_control(struct dma_chan *dchan, enum dma_ctrl_cmd cmd, 
	switch (cmd) {

	case DMA_TERMINATE_ALL:

		disable_chan(chan->phy);

		if (chan->phy) {

			chan->phy->vchan = NULL;

			chan->phy = NULL;

		}

		mmp_pdma_free_phy(chan);

		spin_lock_irqsave(&chan->desc_lock, flags);

		mmp_pdma_free_desc_list(chan, &chan->chain_pending);

		mmp_pdma_free_desc_list(chan, &chan->chain_running);
@@ -769,6 +777,8 @@ static int mmp_pdma_probe(struct platform_device *op) 
		return -ENOMEM;

	pdev->dev = &op->dev;



	spin_lock_init(&pdev->phy_lock);



	iores = platform_get_resource(op, IORESOURCE_MEM, 0);

	if (!iores)

		return -EINVAL;