| Message ID | 20200705115620.51929-1-andriy.shevchenko@linux.intel.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [v1] dmaengine: dw: Initialize channel before each transfer | expand |
On 05-07-20, 14:56, Andy Shevchenko wrote: > 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") > BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=206403 > Reported-by: Tsuchiya Yuto <kitakar@gmail.com> > Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > --- > drivers/dma/dw/core.c | 12 ------------ > 1 file changed, 12 deletions(-) Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
On 05-07-20, 14:56, Andy Shevchenko wrote: > 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. Applied, thanks
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);
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") BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=206403 Reported-by: Tsuchiya Yuto <kitakar@gmail.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> --- drivers/dma/dw/core.c | 12 ------------ 1 file changed, 12 deletions(-)