Commit dc3f595b authored by Codrin Ciubotariu's avatar Codrin Ciubotariu Committed by Vinod Koul
Browse files

dmaengine: at_xdmac: Fix wrongfull report of a channel as in use 



atchan->status variable is used to store two different information:
 - pass channel interrupts status from interrupt handler to tasklet;
 - channel information like whether it is cyclic or paused;

This causes a bug when device_terminate_all() is called,
(AT_XDMAC_CHAN_IS_CYCLIC cleared on atchan->status) and then a late End
of Block interrupt arrives (AT_XDMAC_CIS_BIS), which sets bit 0 of
atchan->status. Bit 0 is also used for AT_XDMAC_CHAN_IS_CYCLIC, so when
a new descriptor for a cyclic transfer is created, the driver reports
the channel as in use:

if (test_and_set_bit(AT_XDMAC_CHAN_IS_CYCLIC, &atchan->status)) {
	dev_err(chan2dev(chan), "channel currently used\n");
	return NULL;
}

This patch fixes the bug by adding a different struct member to keep
the interrupts status separated from the channel status bits.

Fixes: e1f7c9ee ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver")
Signed-off-by: default avatarCodrin Ciubotariu <codrin.ciubotariu@microchip.com>
Acked-by: default avatarLudovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
parent bfeffd15

drivers/dma/at_xdmac.c

+10 −9
Original line number Diff line number Diff line
@@ -203,6 +203,7 @@ struct at_xdmac_chan { 
	u32				save_cim;

	u32				save_cnda;

	u32				save_cndc;

	u32				irq_status;

	unsigned long			status;

	struct tasklet_struct		tasklet;

	struct dma_slave_config		sconfig;
@@ -1580,8 +1581,8 @@ static void at_xdmac_tasklet(unsigned long data) 
	struct at_xdmac_desc	*desc;

	u32			error_mask;



	dev_dbg(chan2dev(&atchan->chan), "%s: status=0x%08lx\n",

		 __func__, atchan->status);

	dev_dbg(chan2dev(&atchan->chan), "%s: status=0x%08x\n",

		__func__, atchan->irq_status);



	error_mask = AT_XDMAC_CIS_RBEIS

		     | AT_XDMAC_CIS_WBEIS
@@ -1589,15 +1590,15 @@ static void at_xdmac_tasklet(unsigned long data) 


	if (at_xdmac_chan_is_cyclic(atchan)) {

		at_xdmac_handle_cyclic(atchan);

	} else if ((atchan->status & AT_XDMAC_CIS_LIS)

		   || (atchan->status & error_mask)) {

	} else if ((atchan->irq_status & AT_XDMAC_CIS_LIS)

		   || (atchan->irq_status & error_mask)) {

		struct dma_async_tx_descriptor  *txd;



		if (atchan->status & AT_XDMAC_CIS_RBEIS)

		if (atchan->irq_status & AT_XDMAC_CIS_RBEIS)

			dev_err(chan2dev(&atchan->chan), "read bus error!!!");

		if (atchan->status & AT_XDMAC_CIS_WBEIS)

		if (atchan->irq_status & AT_XDMAC_CIS_WBEIS)

			dev_err(chan2dev(&atchan->chan), "write bus error!!!");

		if (atchan->status & AT_XDMAC_CIS_ROIS)

		if (atchan->irq_status & AT_XDMAC_CIS_ROIS)

			dev_err(chan2dev(&atchan->chan), "request overflow error!!!");



		spin_lock(&atchan->lock);
@@ -1652,7 +1653,7 @@ static irqreturn_t at_xdmac_interrupt(int irq, void *dev_id) 
			atchan = &atxdmac->chan[i];

			chan_imr = at_xdmac_chan_read(atchan, AT_XDMAC_CIM);

			chan_status = at_xdmac_chan_read(atchan, AT_XDMAC_CIS);

			atchan->status = chan_status & chan_imr;

			atchan->irq_status = chan_status & chan_imr;

			dev_vdbg(atxdmac->dma.dev,

				 "%s: chan%d: imr=0x%x, status=0x%x\n",

				 __func__, i, chan_imr, chan_status);
@@ -1666,7 +1667,7 @@ static irqreturn_t at_xdmac_interrupt(int irq, void *dev_id) 
				 at_xdmac_chan_read(atchan, AT_XDMAC_CDA),

				 at_xdmac_chan_read(atchan, AT_XDMAC_CUBC));



			if (atchan->status & (AT_XDMAC_CIS_RBEIS | AT_XDMAC_CIS_WBEIS))

			if (atchan->irq_status & (AT_XDMAC_CIS_RBEIS | AT_XDMAC_CIS_WBEIS))

				at_xdmac_write(atxdmac, AT_XDMAC_GD, atchan->mask);



			tasklet_schedule(&atchan->tasklet);

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