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dmaengine: dw-axi-dmac: fix PM for system sleep and channel alloc

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The driver only had runtime PM callbacks. If a channel stayed allocated
across system suspend/resume, the runtime usage count could remain
non-zero while hardware state (DMAC_CFG, clocks) was lost, and
axi_dma_runtime_resume() would not run to restore it.

Add system-sleep PM ops that use pm_runtime_force_suspend() and
pm_runtime_force_resume() so suspend/resume reuses the existing
axi_dma_suspend() and axi_dma_resume() paths.

Replace pm_runtime_get() with pm_runtime_resume_and_get() in
dma_chan_alloc_chan_resources() so clocks are enabled before a client
can immediately submit a transfer and touch MMIO.

Signed-off-by: Tze Yee Ng <tze.yee.ng@altera.com>
Link: https://patch.msgid.link/18bf778a3a1cc2f377ef8eb0d1508d8ac6371896.1779688569.git.tze.yee.ng@altera.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Tze Yee Ng
2026-05-25 00:10:22 -07:00
committed by Vinod Koul
parent dc6d681e15
commit df0c2dc687
1 changed files with 9 additions and 2 deletions
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11
drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
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@@ -516,11 +516,17 @@ static void dw_axi_dma_synchronize(struct dma_chan *dchan)
static int dma_chan_alloc_chan_resources(struct dma_chan *dchan)
{
struct axi_dma_chan *chan = dchan_to_axi_dma_chan(dchan);
int ret;
ret = pm_runtime_resume_and_get(chan->chip->dev);
if (ret < 0)
return ret;
/* ASSERT: channel is idle */
if (axi_chan_is_hw_enable(chan)) {
dev_err(chan2dev(chan), "%s is non-idle!\n",
axi_chan_name(chan));
pm_runtime_put(chan->chip->dev);
return -EBUSY;
}
@@ -531,12 +537,11 @@ static int dma_chan_alloc_chan_resources(struct dma_chan *dchan)
64, 0);
if (!chan->desc_pool) {
dev_err(chan2dev(chan), "No memory for descriptors\n");
pm_runtime_put(chan->chip->dev);
return -ENOMEM;
}
dev_vdbg(dchan2dev(dchan), "%s: allocating\n", axi_chan_name(chan));
pm_runtime_get(chan->chip->dev);
return 0;
}
@@ -1663,6 +1668,8 @@ static void dw_remove(struct platform_device *pdev)
}
static const struct dev_pm_ops dw_axi_dma_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
pm_runtime_force_resume)
SET_RUNTIME_PM_OPS(axi_dma_runtime_suspend, axi_dma_runtime_resume, NULL)
};