* DMA & POWER8
@ 2019-02-27 15:57 Илья Кузнецов
2019-03-01 10:32 ` Илья Кузнецов
0 siblings, 1 reply; 2+ messages in thread
From: Илья Кузнецов @ 2019-02-27 15:57 UTC (permalink / raw)
To: linuxppc-dev; +Cc: a.fomichev
We're trying to use Slave-DMA API of the DMA Engine in the linux kernel on
POWER8 OpenPOWER platform. And we discovered that dma_request_channel() always fails.
Does it mean that Turismo hardware does not support Slave-DMA? Or DMA
subsystem in the linux kernel needs to be fixed, doesn't it?
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: DMA & POWER8
2019-02-27 15:57 DMA & POWER8 Илья Кузнецов
@ 2019-03-01 10:32 ` Илья Кузнецов
0 siblings, 0 replies; 2+ messages in thread
From: Илья Кузнецов @ 2019-03-01 10:32 UTC (permalink / raw)
To: linuxppc-dev, Benjamin Herrenschmidt; +Cc: a.fomichev
I'm sorry for previous email content without greeting.
A bit more description… We are working on enabling RDMA over PCIe NTB on
OpenPOWER using https://github.com/ntrdma project. During initialization
dma_request_channel() founds no available channels. We also found that there no
channels at all in dma_device_list. This is probably powerpc specific problem.
Could someone explain if that is hardware limitation or arch specific part
should be changed?
Ben, a while ago you answered regarding DMA master on POWER8, may be you have
idea here also?
Thank you in advance!
Илья Кузнецов <ilya@yadro.com> wrote on Ср [2019-фев-27 18:57:02 +0300]:
>We're trying to use Slave-DMA API of the DMA Engine in the linux kernel on
>POWER8 OpenPOWER platform. And we discovered that dma_request_channel() always fails.
>Does it mean that Turismo hardware does not support Slave-DMA? Or DMA
>subsystem in the linux kernel needs to be fixed, doesn't it?
^ permalink raw reply [flat|nested] 2+ messages in thread
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