[PATCH] dmaengine: pl08x: mark slave channels as DMA_PRIVATE

[Andreas Gabriel-Platschek]

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, 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 <andi.platschek@xxxxxxxxx>
---
 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