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Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ] > > The pl08x slave engine channels are only ever handed out through > explicit requests: DT clients go via pl08x_of_xlate() and the > platform-data path uses dma_request_channel() with a filter, both of > which end up in dma_get_slave_channel(). They are not meant to be > published in the general-purpose channel table. > > Mark the slave device with DMA_PRIVATE at probe time so the dmaengine > core treats it as always-private. Without this, if a dmaengine client > is already active when the device is registered, > dma_async_device_register() takes a reference on every channel, Code change is okay. Are you sure the above description correct? where code set it active when dma_async_device_register(). Frank > and > the subsequent dma_get_slave_channel() from pl08x_of_xlate() fails > because the channel is no longer free (client_count != 0), leaving DT > slave clients unable to acquire channels. > > The memcpy engine stays public as it is intended to be shared through > the per-CPU channel table. > > Signed-off-by: Andreas Gabriel-Platschek > --- > drivers/dma/amba-pl08x.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c > index 543c2eb8cfa8..06881d3f29a9 100644 > --- a/drivers/dma/amba-pl08x.c > +++ b/drivers/dma/amba-pl08x.c > @@ -2775,6 +2775,7 @@ static int pl08x_probe(struct amba_device *adev, const struct amba_id *id) > pl08x->has_slave = true; > dma_cap_set(DMA_SLAVE, pl08x->slave.cap_mask); > dma_cap_set(DMA_CYCLIC, pl08x->slave.cap_mask); > + dma_cap_set(DMA_PRIVATE, pl08x->slave.cap_mask); > pl08x->slave.dev = &adev->dev; > pl08x->slave.device_free_chan_resources = > pl08x_free_chan_resources; > -- > 2.47.3 >