* [PATCH] dmaengine: of-dma: router_xlate to return -EPROBE_DEFER if controller is not yet available
@ 2021-07-17 19:00 Peter Ujfalusi
2021-07-28 7:12 ` Vinod Koul
0 siblings, 1 reply; 2+ messages in thread
From: Peter Ujfalusi @ 2021-07-17 19:00 UTC (permalink / raw)
To: vkoul; +Cc: dmaengine, linux-kernel, linux-omap, tony, nm
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
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] dmaengine: of-dma: router_xlate to return -EPROBE_DEFER if controller is not yet available
2021-07-17 19:00 [PATCH] dmaengine: of-dma: router_xlate to return -EPROBE_DEFER if controller is not yet available Peter Ujfalusi
@ 2021-07-28 7:12 ` Vinod Koul
0 siblings, 0 replies; 2+ messages in thread
From: Vinod Koul @ 2021-07-28 7:12 UTC (permalink / raw)
To: Peter Ujfalusi; +Cc: dmaengine, linux-kernel, linux-omap, tony, nm
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
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2021-07-28 7:12 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-07-17 19:00 [PATCH] dmaengine: of-dma: router_xlate to return -EPROBE_DEFER if controller is not yet available Peter Ujfalusi
2021-07-28 7:12 ` Vinod Koul
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).