# Re: Using DMA

- From: Bill Gatliff \<hidden\>
- Date: 2008-11-06 18:36:58 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2008/11/9447921
- Thread: https://ratatoskr.run/linuxppc-dev/2008/11/9447919/t.md

```text
Scott Wood wrote:
> Bruce_Leonard@selinc.com wrote:
>> In the Cafe driver, Linux Device Drivers 3rd Edition, and
>> DMA-mapping.txt everyone talks about how to allocate buffers using
>> dma/pci_alloc_coherent(), but no one talks about how to actually use
>> it. I'm pretty sure (even in my ignorance) that just allocating a DMA
>> coherent buffer and then copying in and out of it does NOT actually
>> engage the underlying hardware and perform a DMA transfer.

Does the "adma" stuff address this any?


b.g.
-- 
Bill Gatliff
bgat@billgatliff.com
```