Messages in this thread Patch in this message | | | From | Peter Ujfalusi <> | Subject | [PATCH] dmaengine: of-dma: router_xlate to return -EPROBE_DEFER if controller is not yet available | Date | Sat, 17 Jul 2021 22:00:21 +0300 |
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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> --- Hi,
I have noticed the descibed failure sequence on Beagle-x15 board (McASP fails to probe). It must have been broken for some time, I have not booted the board for about a year or so...
Regards, Peter
drivers/dma/of-dma.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c index ec00b20ae8e4..ac61ecda2926 100644 --- a/drivers/dma/of-dma.c +++ b/drivers/dma/of-dma.c @@ -67,8 +67,12 @@ static struct dma_chan *of_dma_router_xlate(struct of_phandle_args *dma_spec, return NULL; ofdma_target = of_dma_find_controller(&dma_spec_target); - if (!ofdma_target) - return NULL; + if (!ofdma_target) { + 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); if (IS_ERR_OR_NULL(chan)) { @@ -89,6 +93,7 @@ static struct dma_chan *of_dma_router_xlate(struct of_phandle_args *dma_spec, } } +err: /* * Need to put the node back since the ofdma->of_dma_route_allocate * has taken it for generating the new, translated dma_spec -- 2.32.0
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