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dmaengine: of-dma: router_xlate to return -EPROBE_DEFER if controller is not yet available

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[ Upstream commit eda97cb095 ]

If the router_xlate can not find the controller in the available DMA
devices then it should return with -EPORBE_DEFER in a same way as the
of_dma_request_slave_channel() does.

The issue can be reproduced if the event router is registered before the
DMA controller itself and a driver would request for a channel before the
controller is registered.
In of_dma_request_slave_channel():
1. of_dma_find_controller() would find the dma_router
2. ofdma->of_dma_xlate() would fail and returned NULL
3. -ENODEV is returned as error code

with this patch we would return in this case the correct -EPROBE_DEFER and
the client can try to request the channel later.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@gmail.com>
Link: https://lore.kernel.org/r/20210717190021.21897-1-peter.ujfalusi@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Peter Ujfalusi 2021-07-17 22:00:21 +03:00 committed by Sasha Levin
parent 12d1322d93
commit e37cf26bd5
1 changed files with 7 additions and 2 deletions
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9
drivers/dma/of-dma.c
View file

@ -65,8 +65,12 @@ static struct dma_chan *of_dma_router_xlate(struct of_phandle_args *dma_spec,
return NULL; return NULL;
ofdma_target = of_dma_find_controller(&dma_spec_target); ofdma_target = of_dma_find_controller(&dma_spec_target);
if (!ofdma_target) if (!ofdma_target) {
return NULL; ofdma->dma_router->route_free(ofdma->dma_router->dev,
route_data);
chan = ERR_PTR(-EPROBE_DEFER);
goto err;
}
chan = ofdma_target->of_dma_xlate(&dma_spec_target, ofdma_target); chan = ofdma_target->of_dma_xlate(&dma_spec_target, ofdma_target);
if (IS_ERR_OR_NULL(chan)) { if (IS_ERR_OR_NULL(chan)) {
@ -77,6 +81,7 @@ static struct dma_chan *of_dma_router_xlate(struct of_phandle_args *dma_spec,
chan->route_data = route_data; chan->route_data = route_data;
} }
err:
/* /*
* Need to put the node back since the ofdma->of_dma_route_allocate * Need to put the node back since the ofdma->of_dma_route_allocate
* has taken it for generating the new, translated dma_spec * has taken it for generating the new, translated dma_spec