How to handle named resources with DT?

Paul Walmsley paul at
Sun Aug 28 21:57:35 EDT 2011


one case that I forgot to mention:

On Sun, 28 Aug 2011, Paul Walmsley wrote:

> Several upstream device drivers get their DMA request line IDs from the 
> device data format[14][15][16].  But more drivers should be doing this 
> than currently are[17]:
> - the device driver author may have hardcoded the DMA request line ID, 
>   assuming it would never change
> - DMA could be broken on the device due to hardware bugs, so it is unused
> - the driver author may just never have gotten around to implementing DMA, 
>   or was reassigned to another project, or couldn't figure it out
> - the device may have its own internal DMA controller logic, so support 
>   for an external DMA controller was simply never added

- the driver may be using software-initiated DMA, which doesn't use a 
  DMA request line, nor does it rely on the device to start or stop DMA.
  Instead, the CPU reprograms the DMA controller when the driver receives 
  an interrupt

- Paul

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