[PATCH v2 06/19] dmaengine: of-dma: Add support for optional router configuration callback

Peter Ujfalusi
2020-11-17T10:57:40Z

Additional configuration for the DMA event router might be needed for a
channel which can not be done during device_alloc_chan_resources callback
since the router information is not yet present for the drivers.

If there is a need for additional configuration for the channel if DMA
router is in use, then the driver can implement the device_router_config
callback.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
---
drivers/dma/of-dma.c | 10 ++++++++++
include/linux/dmaengine.h | 2 ++
2 files changed, 12 insertions(+)

diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
index 8a4f608904b9..ec00b20ae8e4 100644
--- a/drivers/dma/of-dma.c
+++ b/drivers/dma/of-dma.c
@@ -75,8 +75,18 @@ static struct dma_chan *of_dma_router_xlate(struct of_phandle_args *dma_spec,
ofdma->dma_router->route_free(ofdma->dma_router->dev,
route_data);
} else {
+ int ret = 0;
+
chan->router = ofdma->dma_router;
chan->route_data = route_data;
+
+ if (chan->device->device_router_config)
+ ret = chan->device->device_router_config(chan);
+
+ if (ret) {
+ dma_release_channel(chan);
+ chan = ERR_PTR(ret);
+ }
}

/*
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index dd357a747780..d6197fe875af 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -800,6 +800,7 @@ struct dma_filter {
* by tx_status
* @device_alloc_chan_resources: allocate resources and return the
* number of allocated descriptors
+ * @device_router_config: optional callback for DMA router configuration
* @device_free_chan_resources: release DMA channel's resources
* @device_prep_dma_memcpy: prepares a memcpy operation
* @device_prep_dma_xor: prepares a xor operation
@@ -874,6 +875,7 @@ struct dma_device {
enum dma_residue_granularity residue_granularity;

int (*device_alloc_chan_resources)(struct dma_chan *chan);
+ int (*device_router_config)(struct dma_chan *chan);
void (*device_free_chan_resources)(struct dma_chan *chan);

struct dma_async_tx_descriptor *(*device_prep_dma_memcpy)(