Commit d8cb04b0 authored by Nicolas Ferre's avatar Nicolas Ferre Committed by Vinod Koul
Browse files

dmaengine: at_hdmac: replace spin_lock* with irqsave variants 



dmaengine routines can be called from interrupt context and with
interrupts disabled. Whereas spin_unlock_bh can't be called from
such contexts. So this patch converts all spin_lock* routines
to irqsave variants.

Also, spin_lock() used in tasklet is converted to irqsave variants,
as tasklet can be interrupted, and dma requests from such interruptions
may also call spin_lock.

Idea from dw_dmac patch by Viresh Kumar.

Signed-off-by: default avatarNicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: default avatarUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
parent ef298c21

drivers/dma/at_hdmac.c

+30 −22
Original line number Diff line number Diff line
@@ -107,10 +107,11 @@ static struct at_desc *atc_desc_get(struct at_dma_chan *atchan) 
{

	struct at_desc *desc, *_desc;

	struct at_desc *ret = NULL;

	unsigned long flags;

	unsigned int i = 0;

	LIST_HEAD(tmp_list);



	spin_lock_bh(&atchan->lock);

	spin_lock_irqsave(&atchan->lock, flags);

	list_for_each_entry_safe(desc, _desc, &atchan->free_list, desc_node) {

		i++;

		if (async_tx_test_ack(&desc->txd)) {
@@ -121,7 +122,7 @@ static struct at_desc *atc_desc_get(struct at_dma_chan *atchan) 
		dev_dbg(chan2dev(&atchan->chan_common),

				"desc %p not ACKed\n", desc);

	}

	spin_unlock_bh(&atchan->lock);

	spin_unlock_irqrestore(&atchan->lock, flags);

	dev_vdbg(chan2dev(&atchan->chan_common),

		"scanned %u descriptors on freelist\n", i);
@@ -129,9 +130,9 @@ static struct at_desc *atc_desc_get(struct at_dma_chan *atchan) 
	if (!ret) {

		ret = atc_alloc_descriptor(&atchan->chan_common, GFP_ATOMIC);

		if (ret) {

			spin_lock_bh(&atchan->lock);

			spin_lock_irqsave(&atchan->lock, flags);

			atchan->descs_allocated++;

			spin_unlock_bh(&atchan->lock);

			spin_unlock_irqrestore(&atchan->lock, flags);

		} else {

			dev_err(chan2dev(&atchan->chan_common),

					"not enough descriptors available\n");
@@ -150,8 +151,9 @@ static void atc_desc_put(struct at_dma_chan *atchan, struct at_desc *desc) 
{

	if (desc) {

		struct at_desc *child;

		unsigned long flags;



		spin_lock_bh(&atchan->lock);

		spin_lock_irqsave(&atchan->lock, flags);

		list_for_each_entry(child, &desc->tx_list, desc_node)

			dev_vdbg(chan2dev(&atchan->chan_common),

					"moving child desc %p to freelist\n",
@@ -160,7 +162,7 @@ static void atc_desc_put(struct at_dma_chan *atchan, struct at_desc *desc) 
		dev_vdbg(chan2dev(&atchan->chan_common),

			 "moving desc %p to freelist\n", desc);

		list_add(&desc->desc_node, &atchan->free_list);

		spin_unlock_bh(&atchan->lock);

		spin_unlock_irqrestore(&atchan->lock, flags);

	}

}
@@ -471,8 +473,9 @@ static void atc_handle_cyclic(struct at_dma_chan *atchan) 
static void atc_tasklet(unsigned long data)

{

	struct at_dma_chan *atchan = (struct at_dma_chan *)data;

	unsigned long flags;



	spin_lock(&atchan->lock);

	spin_lock_irqsave(&atchan->lock, flags);

	if (test_and_clear_bit(ATC_IS_ERROR, &atchan->status))

		atc_handle_error(atchan);

	else if (test_bit(ATC_IS_CYCLIC, &atchan->status))
@@ -480,7 +483,7 @@ static void atc_tasklet(unsigned long data) 
	else

		atc_advance_work(atchan);



	spin_unlock(&atchan->lock);

	spin_unlock_irqrestore(&atchan->lock, flags);

}



static irqreturn_t at_dma_interrupt(int irq, void *dev_id)
@@ -539,8 +542,9 @@ static dma_cookie_t atc_tx_submit(struct dma_async_tx_descriptor *tx) 
	struct at_desc		*desc = txd_to_at_desc(tx);

	struct at_dma_chan	*atchan = to_at_dma_chan(tx->chan);

	dma_cookie_t		cookie;

	unsigned long		flags;



	spin_lock_bh(&atchan->lock);

	spin_lock_irqsave(&atchan->lock, flags);

	cookie = atc_assign_cookie(atchan, desc);



	if (list_empty(&atchan->active_list)) {
@@ -554,7 +558,7 @@ static dma_cookie_t atc_tx_submit(struct dma_async_tx_descriptor *tx) 
		list_add_tail(&desc->desc_node, &atchan->queue);

	}



	spin_unlock_bh(&atchan->lock);

	spin_unlock_irqrestore(&atchan->lock, flags);



	return cookie;

}
@@ -927,28 +931,29 @@ static int atc_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, 
	struct at_dma_chan	*atchan = to_at_dma_chan(chan);

	struct at_dma		*atdma = to_at_dma(chan->device);

	int			chan_id = atchan->chan_common.chan_id;

	unsigned long		flags;



	LIST_HEAD(list);



	dev_vdbg(chan2dev(chan), "atc_control (%d)\n", cmd);



	if (cmd == DMA_PAUSE) {

		spin_lock_bh(&atchan->lock);

		spin_lock_irqsave(&atchan->lock, flags);



		dma_writel(atdma, CHER, AT_DMA_SUSP(chan_id));

		set_bit(ATC_IS_PAUSED, &atchan->status);



		spin_unlock_bh(&atchan->lock);

		spin_unlock_irqrestore(&atchan->lock, flags);

	} else if (cmd == DMA_RESUME) {

		if (!test_bit(ATC_IS_PAUSED, &atchan->status))

			return 0;



		spin_lock_bh(&atchan->lock);

		spin_lock_irqsave(&atchan->lock, flags);



		dma_writel(atdma, CHDR, AT_DMA_RES(chan_id));

		clear_bit(ATC_IS_PAUSED, &atchan->status);



		spin_unlock_bh(&atchan->lock);

		spin_unlock_irqrestore(&atchan->lock, flags);

	} else if (cmd == DMA_TERMINATE_ALL) {

		struct at_desc	*desc, *_desc;

		/*
@@ -957,7 +962,7 @@ static int atc_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, 
		 * channel. We still have to poll the channel enable bit due

		 * to AHB/HSB limitations.

		 */

		spin_lock_bh(&atchan->lock);

		spin_lock_irqsave(&atchan->lock, flags);



		/* disabling channel: must also remove suspend state */

		dma_writel(atdma, CHDR, AT_DMA_RES(chan_id) | atchan->mask);
@@ -978,7 +983,7 @@ static int atc_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, 
		/* if channel dedicated to cyclic operations, free it */

		clear_bit(ATC_IS_CYCLIC, &atchan->status);



		spin_unlock_bh(&atchan->lock);

		spin_unlock_irqrestore(&atchan->lock, flags);

	} else {

		return -ENXIO;

	}
@@ -1004,9 +1009,10 @@ atc_tx_status(struct dma_chan *chan, 
	struct at_dma_chan	*atchan = to_at_dma_chan(chan);

	dma_cookie_t		last_used;

	dma_cookie_t		last_complete;

	unsigned long		flags;

	enum dma_status		ret;



	spin_lock_bh(&atchan->lock);

	spin_lock_irqsave(&atchan->lock, flags);



	last_complete = atchan->completed_cookie;

	last_used = chan->cookie;
@@ -1021,7 +1027,7 @@ atc_tx_status(struct dma_chan *chan, 
		ret = dma_async_is_complete(cookie, last_complete, last_used);

	}



	spin_unlock_bh(&atchan->lock);

	spin_unlock_irqrestore(&atchan->lock, flags);



	if (ret != DMA_SUCCESS)

		dma_set_tx_state(txstate, last_complete, last_used,
@@ -1046,6 +1052,7 @@ atc_tx_status(struct dma_chan *chan, 
static void atc_issue_pending(struct dma_chan *chan)

{

	struct at_dma_chan	*atchan = to_at_dma_chan(chan);

	unsigned long		flags;



	dev_vdbg(chan2dev(chan), "issue_pending\n");
@@ -1053,11 +1060,11 @@ static void atc_issue_pending(struct dma_chan *chan) 
	if (test_bit(ATC_IS_CYCLIC, &atchan->status))

		return;



	spin_lock_bh(&atchan->lock);

	spin_lock_irqsave(&atchan->lock, flags);

	if (!atc_chan_is_enabled(atchan)) {

		atc_advance_work(atchan);

	}

	spin_unlock_bh(&atchan->lock);

	spin_unlock_irqrestore(&atchan->lock, flags);

}



/**
@@ -1073,6 +1080,7 @@ static int atc_alloc_chan_resources(struct dma_chan *chan) 
	struct at_dma		*atdma = to_at_dma(chan->device);

	struct at_desc		*desc;

	struct at_dma_slave	*atslave;

	unsigned long		flags;

	int			i;

	u32			cfg;

	LIST_HEAD(tmp_list);
@@ -1116,11 +1124,11 @@ static int atc_alloc_chan_resources(struct dma_chan *chan) 
		list_add_tail(&desc->desc_node, &tmp_list);

	}



	spin_lock_bh(&atchan->lock);

	spin_lock_irqsave(&atchan->lock, flags);

	atchan->descs_allocated = i;

	list_splice(&tmp_list, &atchan->free_list);

	atchan->completed_cookie = chan->cookie = 1;

	spin_unlock_bh(&atchan->lock);

	spin_unlock_irqrestore(&atchan->lock, flags);



	/* channel parameters */

	channel_writel(atchan, CFG, cfg);

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