From mboxrd@z Thu Jan 1 00:00:00 1970 From: zonque@gmail.com (Daniel Mack) Date: Wed, 7 Aug 2013 12:19:19 +0200 Subject: [PATCH 01/12] dma: mmp_pdma: add protect when alloc/free phy channels In-Reply-To: <1375870770-14263-1-git-send-email-zonque@gmail.com> References: <1375870770-14263-1-git-send-email-zonque@gmail.com> Message-ID: <1375870770-14263-2-git-send-email-zonque@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: Xiang Wang 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: Xiang Wang --- drivers/dma/mmp_pdma.c | 42 ++++++++++++++++++++++++++---------------- 1 file changed, 26 insertions(+), 16 deletions(-) diff --git a/drivers/dma/mmp_pdma.c b/drivers/dma/mmp_pdma.c index c26699f..226158d 100644 --- a/drivers/dma/mmp_pdma.c +++ b/drivers/dma/mmp_pdma.c @@ -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); @@ -777,6 +785,8 @@ 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; -- 1.8.3.1