From f81614d0e446cd6f3e04ac8ae8f95c86eeec6a80 Mon Sep 17 00:00:00 2001
From: Peter Ujfalusi <peter.ujfalusi@ti.com>
Date: Tue, 8 Dec 2020 11:04:27 +0200
Subject: [PATCH] dmaengine: of-dma: Add support for optional router
 configuration callback

commit 4f910c035f38053ac8eb63a672c78862c535cd0f upstream.

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>
Link: https://lore.kernel.org/r/20201208090440.31792-8-peter.ujfalusi@ti.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
[s-anna@ti.com: cherry-pick commit '4f910c035f38' from v5.11]
Signed-off-by: Suman Anna <s-anna@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 4be433482053..ac61ecda2926 100644
--- a/drivers/dma/of-dma.c
+++ b/drivers/dma/of-dma.c
@@ -79,8 +79,18 @@ 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);
+		}
 	}
 
 err:
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 256592c0a365..86beb2b84bac 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -801,6 +801,7 @@ 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
@@ -875,6 +876,7 @@ 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)(
