linux-kernel - [PATCH v2 2/2] dmaengine: dw: fix cyclic transfer callbacks

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Message-Id: <1452517469-26922-3-git-send-email-mans@mansr.com>
Date:	Mon, 11 Jan 2016 13:04:29 +0000
From:	Mans Rullgard <mans@...sr.com>
To:	Viresh Kumar <vireshk@...nel.org>,
	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
	Dan Williams <dan.j.williams@...el.com>,
	Vinod Koul <vinod.koul@...el.com>, dmaengine@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v2 2/2] dmaengine: dw: fix cyclic transfer callbacks

Cyclic transfer callbacks rely on block completion interrupts which were
disabled in commit ff7b05f29fd4 ("dmaengine/dw_dmac: Don't handle block
interrupts").  This re-enables block interrupts so the cyclic callbacks
can work.  Other transfer types are not affected as they set the INT_EN
bit only on the last block.

Fixes: ff7b05f29fd4 ("dmaengine/dw_dmac: Don't handle block interrupts")
Signed-off-by: Mans Rullgard <mans@...sr.com>
---
Changes:
- new patch
---
 drivers/dma/dw/core.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
index af2b92f8501e..b92662722404 100644
--- a/drivers/dma/dw/core.c
+++ b/drivers/dma/dw/core.c
@@ -156,6 +156,7 @@ static void dwc_initialize(struct dw_dma_chan *dwc)
 
 	/* Enable interrupts */
 	channel_set_bit(dw, MASK.XFER, dwc->mask);
+	channel_set_bit(dw, MASK.BLOCK, dwc->mask);
 	channel_set_bit(dw, MASK.ERROR, dwc->mask);
 
 	dwc->initialized = true;
@@ -536,16 +537,17 @@ EXPORT_SYMBOL(dw_dma_get_dst_addr);
 
 /* Called with dwc->lock held and all DMAC interrupts disabled */
 static void dwc_handle_cyclic(struct dw_dma *dw, struct dw_dma_chan *dwc,
-		u32 status_err, u32 status_xfer)
+		u32 status_block, u32 status_err, u32 status_xfer)
 {
 	unsigned long flags;
 
-	if (dwc->mask) {
+	if (status_block & dwc->mask) {
 		void (*callback)(void *param);
 		void *callback_param;
 
 		dev_vdbg(chan2dev(&dwc->chan), "new cyclic period llp 0x%08x\n",
 				channel_readl(dwc, LLP));
+		dma_writel(dw, CLEAR.BLOCK, dwc->mask);
 
 		callback = dwc->cdesc->period_callback;
 		callback_param = dwc->cdesc->period_callback_param;
@@ -577,6 +579,7 @@ static void dwc_handle_cyclic(struct dw_dma *dw, struct dw_dma_chan *dwc,
 		channel_writel(dwc, CTL_LO, 0);
 		channel_writel(dwc, CTL_HI, 0);
 
+		dma_writel(dw, CLEAR.BLOCK, dwc->mask);
 		dma_writel(dw, CLEAR.ERROR, dwc->mask);
 		dma_writel(dw, CLEAR.XFER, dwc->mask);
 
@@ -593,10 +596,12 @@ static void dw_dma_tasklet(unsigned long data)
 {
 	struct dw_dma *dw = (struct dw_dma *)data;
 	struct dw_dma_chan *dwc;
+	u32 status_block;
 	u32 status_xfer;
 	u32 status_err;
 	int i;
 
+	status_block = dma_readl(dw, RAW.BLOCK);
 	status_xfer = dma_readl(dw, RAW.XFER);
 	status_err = dma_readl(dw, RAW.ERROR);
 
@@ -605,7 +610,8 @@ static void dw_dma_tasklet(unsigned long data)
 	for (i = 0; i < dw->dma.chancnt; i++) {
 		dwc = &dw->chan[i];
 		if (test_bit(DW_DMA_IS_CYCLIC, &dwc->flags))
-			dwc_handle_cyclic(dw, dwc, status_err, status_xfer);
+			dwc_handle_cyclic(dw, dwc, status_block, status_err,
+					status_xfer);
 		else if (status_err & (1 << i))
 			dwc_handle_error(dw, dwc);
 		else if (status_xfer & (1 << i))
@@ -616,6 +622,7 @@ static void dw_dma_tasklet(unsigned long data)
 	 * Re-enable interrupts.
 	 */
 	channel_set_bit(dw, MASK.XFER, dw->all_chan_mask);
+	channel_set_bit(dw, MASK.BLOCK, dw->all_chan_mask);
 	channel_set_bit(dw, MASK.ERROR, dw->all_chan_mask);
 }
 
@@ -635,6 +642,7 @@ static irqreturn_t dw_dma_interrupt(int irq, void *dev_id)
 	 * softirq handler.
 	 */
 	channel_clear_bit(dw, MASK.XFER, dw->all_chan_mask);
+	channel_clear_bit(dw, MASK.BLOCK, dw->all_chan_mask);
 	channel_clear_bit(dw, MASK.ERROR, dw->all_chan_mask);
 
 	status = dma_readl(dw, STATUS_INT);
@@ -645,6 +653,7 @@ static irqreturn_t dw_dma_interrupt(int irq, void *dev_id)
 
 		/* Try to recover */
 		channel_clear_bit(dw, MASK.XFER, (1 << 8) - 1);
+		channel_clear_bit(dw, MASK.BLOCK, (1 << 8) - 1);
 		channel_clear_bit(dw, MASK.SRC_TRAN, (1 << 8) - 1);
 		channel_clear_bit(dw, MASK.DST_TRAN, (1 << 8) - 1);
 		channel_clear_bit(dw, MASK.ERROR, (1 << 8) - 1);
@@ -1111,6 +1120,7 @@ static void dw_dma_off(struct dw_dma *dw)
 	dma_writel(dw, CFG, 0);
 
 	channel_clear_bit(dw, MASK.XFER, dw->all_chan_mask);
+	channel_clear_bit(dw, MASK.BLOCK, dw->all_chan_mask);
 	channel_clear_bit(dw, MASK.SRC_TRAN, dw->all_chan_mask);
 	channel_clear_bit(dw, MASK.DST_TRAN, dw->all_chan_mask);
 	channel_clear_bit(dw, MASK.ERROR, dw->all_chan_mask);
@@ -1216,6 +1226,7 @@ static void dwc_free_chan_resources(struct dma_chan *chan)
 
 	/* Disable interrupts */
 	channel_clear_bit(dw, MASK.XFER, dwc->mask);
+	channel_clear_bit(dw, MASK.BLOCK, dwc->mask);
 	channel_clear_bit(dw, MASK.ERROR, dwc->mask);
 
 	spin_unlock_irqrestore(&dwc->lock, flags);
@@ -1458,6 +1469,7 @@ void dw_dma_cyclic_free(struct dma_chan *chan)
 
 	dwc_chan_disable(dw, dwc);
 
+	dma_writel(dw, CLEAR.BLOCK, dwc->mask);
 	dma_writel(dw, CLEAR.ERROR, dwc->mask);
 	dma_writel(dw, CLEAR.XFER, dwc->mask);
 
@@ -1546,9 +1558,6 @@ int dw_dma_probe(struct dw_dma_chip *chip, struct dw_dma_platform_data *pdata)
 	/* Force dma off, just in case */
 	dw_dma_off(dw);
 
-	/* Disable BLOCK interrupts as well */
-	channel_clear_bit(dw, MASK.BLOCK, dw->all_chan_mask);
-
 	/* Create a pool of consistent memory blocks for hardware descriptors */
 	dw->desc_pool = dmam_pool_create("dw_dmac_desc_pool", chip->dev,
 					 sizeof(struct dw_desc), 4, 0);
-- 
2.7.0