Date: Thu, 13 Dec 2018 08:53:15 -0700 From: Warner Losh <imp@bsdimp.com> To: Rajesh Kumar <rajfbsd@gmail.com> Cc: freebsd-drivers@freebsd.org, FreeBSD Hackers <freebsd-hackers@freebsd.org> Subject: Re: How to use the DMA Engine in FreeBSD? Message-ID: <CANCZdfrEv9o6_ydp9Qe73O1v6NqHFtivHpw4m2PKhTyAVaPR9g@mail.gmail.com> In-Reply-To: <CAAO%2BANOty8FeOR7VQdXmxWy5y288pm=Q4cswHJ1BbgT2h1cUWg@mail.gmail.com> References: <CAAO%2BANOty8FeOR7VQdXmxWy5y288pm=Q4cswHJ1BbgT2h1cUWg@mail.gmail.com>
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On Thu, Dec 13, 2018, 3:04 AM Rajesh Kumar <rajfbsd@gmail.com wrote: > Hi, > > Is there any good documentation available to understand the existing > support, API's and how-to use the DMA Engine in FreeBSD? > Usually you just use pci busmastering and it just works. I am trying to write a test driver which will use DMA Engine to do the data > transfer (rather than plain memcpy which involves cpu). Can anyone point > to any driver implementation which has similar functions implemented? I > see references to SYS_RES_DRQ to allocate DMA channels and play around. But > that seems to be specific to ISA. Can it be used for PCI drivers as well? > No. ISA DMA is only for really old hardware without it's own DMA engine. Look at the busdma api/man page. Warner > Thanks, > Rajesh. > _______________________________________________ > freebsd-drivers@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-drivers > To unsubscribe, send any mail to "freebsd-drivers-unsubscribe@freebsd.org" >
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