[PATCH 3.16.y-ckt 085/104] dmaengine: dw: properly read DWC_PARAMS register
From: Luis Henriques
Date: Mon Oct 26 2015 - 09:45:12 EST
3.16.7-ckt19 -stable review patch. If anyone has any objections, please let me know.
------------------
From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
commit 6bea0f6d1c47b07be88dfd93f013ae05fcb3d8bf upstream.
In case we have less than maximum allowed channels (8) and autoconfiguration is
enabled the DWC_PARAMS read is wrong because it uses different arithmetic to
what is needed for channel priority setup.
Re-do the caclulations properly. This now works on AVR32 board well.
Fixes: fed2574b3c9f (dw_dmac: introduce software emulation of LLP transfers)
Cc: yitian.bu@xxxxxxxxxxxxxx
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Signed-off-by: Vinod Koul <vinod.koul@xxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
drivers/dma/dw/core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
index 525b4654bd90..a1315dd54514 100644
--- a/drivers/dma/dw/core.c
+++ b/drivers/dma/dw/core.c
@@ -1573,7 +1573,6 @@ int dw_dma_probe(struct dw_dma_chip *chip, struct dw_dma_platform_data *pdata)
INIT_LIST_HEAD(&dw->dma.channels);
for (i = 0; i < nr_channels; i++) {
struct dw_dma_chan *dwc = &dw->chan[i];
- int r = nr_channels - i - 1;
dwc->chan.device = &dw->dma;
dma_cookie_init(&dwc->chan);
@@ -1585,7 +1584,7 @@ int dw_dma_probe(struct dw_dma_chip *chip, struct dw_dma_platform_data *pdata)
/* 7 is highest priority & 0 is lowest. */
if (pdata->chan_priority == CHAN_PRIORITY_ASCENDING)
- dwc->priority = r;
+ dwc->priority = nr_channels - i - 1;
else
dwc->priority = i;
@@ -1605,6 +1604,7 @@ int dw_dma_probe(struct dw_dma_chip *chip, struct dw_dma_platform_data *pdata)
/* Hardware configuration */
if (autocfg) {
unsigned int dwc_params;
+ unsigned int r = DW_DMA_MAX_NR_CHANNELS - i - 1;
void __iomem *addr = chip->regs + r * sizeof(u32);
dwc_params = dma_read_byaddr(addr, DWC_PARAMS);
--
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