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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: e1f7c9eee7 ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver")
Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Codrin Ciubotariu 2019-01-23 16:33:47 +00:00 committed by Vinod Koul
parent bfeffd1552
commit dc3f595b66
1 changed files with 10 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
drivers/dma/at_xdmac.c
View File

@ -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);