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authorAndy Shevchenko <andriy.shevchenko@linux.intel.com>2020-07-05 14:56:20 +0300
committerVinod Koul <vkoul@kernel.org>2020-07-06 10:21:05 +0530
commit99ba8b9b0d9780e9937eb1d488d120e9e5c2533d (patch)
tree1a5f69b6e0cf89684386d41f83d0bbc2104e4ec7
parente3122822a74033ba8d6d9af855078f9ab741e33f (diff)
dmaengine: dw: Initialize channel before each transfer
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.intel.com Signed-off-by: Vinod Koul <vkoul@kernel.org>
-rw-r--r--drivers/dma/dw/core.c12
1 files changed, 0 insertions, 12 deletions
diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
index 21cb2a58dbd2..a1b56f52db2f 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);