| Message ID | 20210717190021.21897-1-peter.ujfalusi@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | dmaengine: of-dma: router_xlate to return -EPROBE_DEFER if controller is not yet available | expand |
On 17-07-21, 22:00, Peter Ujfalusi wrote: > 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. Applied, thanks -- ~Vinod
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
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(-)