Hi Peter,
On 02-10-20, 11:48, Peter Ujfalusi wrote:
> It depends which is best for the use case.
> I see the metadata useful when you need to send different
> metadata/configuration with each transfer.
> It can be also useful when you need it seldom, but for your use case and
> setup the dma_slave_config extended with
>
> enum dmaengine_peripheral peripheral_type;
> void *peripheral_config;
>
> would be a bit more explicit.
>
> I would then deal with the peripheral config in this way:
> when the DMA driver's device_config is called, I would take the
> parameters and set a flag that the config needs to be processed as it
> has changed.
> In the next prep_slave_sg() then I would prepare the TREs with the
> config and clear the flag that the next transfer does not need the
> configuration anymore.
>
> In this way each dmaengine_slave_config() will trigger at the next
> prep_slave_sg time configuration update for the peripheral to be
> included in the TREs.
> The set_config would be internal to the DMA driver, clients just need to
> update the configuration when they need to and everything is taken care of.
Ok I am going to drop the dmaengine_peripheral and make
peripheral_config as as you proposed.
So will add following to dma_slave_config:
void *peripheral_config;
Driver can define the config they would like and use.
We can eventually look at common implementations and try to unify once
we have more users
--
~Vinod
