90 lines
3.1 KiB
Diff
90 lines
3.1 KiB
Diff
From 425b74d21a8f86fcfbbfaee22687af7bd47275aa Mon Sep 17 00:00:00 2001
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From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
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Date: Sun, 5 Jul 2020 14:56:20 +0300
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Subject: [PATCH] dmaengine: dw: Initialize channel before each transfer
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In some cases DMA can be used only with a consumer which does runtime power
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management and on the platforms, that have DMA auto power gating logic
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(see comments in the drivers/acpi/acpi_lpss.c), may result in DMA losing
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its context. Simple mitigation of this issue is to initialize channel
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each time the consumer initiates a transfer.
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Fixes: cfdf5b6cc598 ("dw_dmac: add support for Lynxpoint DMA controllers")
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Reported-by: Tsuchiya Yuto <kitakar@gmail.com>
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Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
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Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=206403
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Link: https://lore.kernel.org/r/20200705115620.51929-1-andriy.shevchenko@linux.intel.com
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Signed-off-by: Vinod Koul <vkoul@kernel.org>
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(cherry picked from commit 99ba8b9b0d9780e9937eb1d488d120e9e5c2533d)
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[Reason for cherry-picking this commit:
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This commit fixes touch input when using DMA mode on Surface 3's
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touchscreen.
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Note: this commit was not backported to v4.19 by upstream. For now,
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backport this patch ourselves.]
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[ Conflicts:
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drivers/dma/dw/core.c
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Resolved conflict by accepting current change then removed
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DW_DMA_IS_INITIALIZED lines]
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Signed-off-by: Tsuchiya Yuto <kitakar@gmail.com>
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Patchset: surface3-touchscreen-dma-fix
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---
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drivers/dma/dw/core.c | 12 ------------
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1 file changed, 12 deletions(-)
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diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
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index 055d83b6cb68..acf64302a2b2 100644
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--- a/drivers/dma/dw/core.c
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+++ b/drivers/dma/dw/core.c
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@@ -180,9 +180,6 @@ static void dwc_initialize(struct dw_dma_chan *dwc)
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{
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struct dw_dma *dw = to_dw_dma(dwc->chan.device);
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- if (test_bit(DW_DMA_IS_INITIALIZED, &dwc->flags))
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- return;
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-
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if (dw->pdata->is_idma32)
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dwc_initialize_chan_idma32(dwc);
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else
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@@ -191,8 +188,6 @@ static void dwc_initialize(struct dw_dma_chan *dwc)
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/* Enable interrupts */
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channel_set_bit(dw, MASK.XFER, dwc->mask);
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channel_set_bit(dw, MASK.ERROR, dwc->mask);
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-
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- set_bit(DW_DMA_IS_INITIALIZED, &dwc->flags);
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}
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/*----------------------------------------------------------------------*/
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@@ -1091,8 +1086,6 @@ static void idma32_fifo_partition(struct dw_dma *dw)
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static void dw_dma_off(struct dw_dma *dw)
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{
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- unsigned int i;
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-
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dma_writel(dw, CFG, 0);
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channel_clear_bit(dw, MASK.XFER, dw->all_chan_mask);
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@@ -1103,9 +1096,6 @@ static void dw_dma_off(struct dw_dma *dw)
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while (dma_readl(dw, CFG) & DW_CFG_DMA_EN)
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cpu_relax();
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-
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- for (i = 0; i < dw->dma.chancnt; i++)
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- clear_bit(DW_DMA_IS_INITIALIZED, &dw->chan[i].flags);
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}
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static void dw_dma_on(struct dw_dma *dw)
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@@ -1170,8 +1160,6 @@ static void dwc_free_chan_resources(struct dma_chan *chan)
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/* Clear custom channel configuration */
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memset(&dwc->dws, 0, sizeof(struct dw_dma_slave));
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- clear_bit(DW_DMA_IS_INITIALIZED, &dwc->flags);
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-
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/* Disable interrupts */
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channel_clear_bit(dw, MASK.XFER, dwc->mask);
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channel_clear_bit(dw, MASK.BLOCK, dwc->mask);
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--
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2.32.0
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