From: Andy Shevchenko andriy.shevchenko@linux.intel.com
[ Upstream commit 99ba8b9b0d9780e9937eb1d488d120e9e5c2533d ]
In some cases DMA can be used only with a consumer which does runtime power management and on the platforms, that have DMA auto power gating logic (see comments in the drivers/acpi/acpi_lpss.c), may result in DMA losing its context. Simple mitigation of this issue is to initialize channel each time the consumer initiates a transfer.
Fixes: cfdf5b6cc598 ("dw_dmac: add support for Lynxpoint DMA controllers") Reported-by: Tsuchiya Yuto kitakar@gmail.com Signed-off-by: Andy Shevchenko andriy.shevchenko@linux.intel.com Acked-by: Viresh Kumar viresh.kumar@linaro.org BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=206403 Link: https://lore.kernel.org/r/20200705115620.51929-1-andriy.shevchenko@linux.int... Signed-off-by: Vinod Koul vkoul@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/dma/dw/core.c | 12 ------------ 1 file changed, 12 deletions(-)
diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c index 21cb2a58dbd29..a1b56f52db2f2 100644 --- a/drivers/dma/dw/core.c +++ b/drivers/dma/dw/core.c @@ -118,16 +118,11 @@ static void dwc_initialize(struct dw_dma_chan *dwc) { struct dw_dma *dw = to_dw_dma(dwc->chan.device);
- if (test_bit(DW_DMA_IS_INITIALIZED, &dwc->flags)) - return; - dw->initialize_chan(dwc);
/* Enable interrupts */ channel_set_bit(dw, MASK.XFER, dwc->mask); channel_set_bit(dw, MASK.ERROR, dwc->mask); - - set_bit(DW_DMA_IS_INITIALIZED, &dwc->flags); }
/*----------------------------------------------------------------------*/ @@ -954,8 +949,6 @@ static void dwc_issue_pending(struct dma_chan *chan)
void do_dw_dma_off(struct dw_dma *dw) { - unsigned int i; - dma_writel(dw, CFG, 0);
channel_clear_bit(dw, MASK.XFER, dw->all_chan_mask); @@ -966,9 +959,6 @@ void do_dw_dma_off(struct dw_dma *dw)
while (dma_readl(dw, CFG) & DW_CFG_DMA_EN) cpu_relax(); - - for (i = 0; i < dw->dma.chancnt; i++) - clear_bit(DW_DMA_IS_INITIALIZED, &dw->chan[i].flags); }
void do_dw_dma_on(struct dw_dma *dw) @@ -1032,8 +1022,6 @@ static void dwc_free_chan_resources(struct dma_chan *chan) /* Clear custom channel configuration */ memset(&dwc->dws, 0, sizeof(struct dw_dma_slave));
- clear_bit(DW_DMA_IS_INITIALIZED, &dwc->flags); - /* Disable interrupts */ channel_clear_bit(dw, MASK.XFER, dwc->mask); channel_clear_bit(dw, MASK.BLOCK, dwc->mask);