Question about DMA mapping.
Hi everyone, Thank for your time, I'm new to linux kernel. I am reading LDD3 chapter 15, Dirrect Memory Access section. I see that when I call function /dma_map_single/ and /dma_unmap_single/, I need to pass a direction as a parameter. I wonder what is purpose of it? Does It relate to something like permission? Can I call /dma_map_single /with DMA_BIDIRECTIONAL and then call /dma_unmap_single /with DMA_TO_DEVICE? Will it cause any problem? Thank you very much. ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: suggestions for good in-kernel examples of simple ethernet/PHY drivers?
On Thu, 30 Aug 2018 13:27:13 -0400, "Robert P. J. Day" said: > i'm already looking at that, but what i wanted was an example of an > existing, physical driver that shows how simple the design can be (if > such a thing exists). For some reason, engineers building network devices almost never manage to create a device that has a clean design with few warts. It's almost as if they were following in the steps of Persian rug makers, where hand-woven rugs always have at least one (intentional) error, because only Allah is perfection pgpwVbSX6t4jN.pgp Description: PGP signature ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: suggestions for good in-kernel examples of simple ethernet/PHY drivers?
On Thu, 30 Aug 2018, Woody Wu wrote: > Maybe the dummy NIC driver? > > On Thu, Aug 30, 2018 at 7:52 PM wrote: > while i'm actually learning about the intricacies of the kernel > networking > stack, i was looking for what would be really good examples of existing > network drivers that could be used as examples for future tutorials, as > nothing is as informational as seeing something that actually works. > > there are, of course, a ton of net drivers already in the kernel, but > many of them are fairly complex, and might define custom methods to > handle > individual quirks and so on, so what i'm interested in is pointers to > examples that are nice and simple and straightforward that could be used > for a walkthrough of net driver design. thoughts? > > rday > > p.s. i'm already aware of the mass of documentation under > Documentation/networking -- any pointers to online net driver > design and tutorials would be appreciated. > > and, yes, i'm also digging through LDD3, https://lwn.net/Kernel/LDD3/. i'm already looking at that, but what i wanted was an example of an existing, physical driver that shows how simple the design can be (if such a thing exists). rday -- Robert P. J. Day Ottawa, Ontario, CANADA http://crashcourse.ca/dokuwiki Twitter: http://twitter.com/rpjday LinkedIn: http://ca.linkedin.com/in/rpjday ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: suggestions for good in-kernel examples of simple ethernet/PHY drivers?
Maybe the dummy NIC driver? On Thu, Aug 30, 2018 at 7:52 PM wrote: >while i'm actually learning about the intricacies of the kernel > networking > stack, i was looking for what would be really good examples of existing > network drivers that could be used as examples for future tutorials, as > nothing is as informational as seeing something that actually works. > >there are, of course, a ton of net drivers already in the kernel, but > many of them are fairly complex, and might define custom methods to handle > individual quirks and so on, so what i'm interested in is pointers to > examples that are nice and simple and straightforward that could be used > for a walkthrough of net driver design. thoughts? > > rday > > p.s. i'm already aware of the mass of documentation under > Documentation/networking -- any pointers to online net driver > design and tutorials would be appreciated. > > and, yes, i'm also digging through LDD3, https://lwn.net/Kernel/LDD3/. > > > ___ > Kernelnewbies mailing list > Kernelnewbies@kernelnewbies.org > https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > -- Life is the only flaw in an otherwise perfect nonexistence -- Schopenhauer woody public key at http://subkeys.pgp.net:11371 (narkewo...@gmail.com) ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
suggestions for good in-kernel examples of simple ethernet/PHY drivers?
while i'm actually learning about the intricacies of the kernel networking stack, i was looking for what would be really good examples of existing network drivers that could be used as examples for future tutorials, as nothing is as informational as seeing something that actually works. there are, of course, a ton of net drivers already in the kernel, but many of them are fairly complex, and might define custom methods to handle individual quirks and so on, so what i'm interested in is pointers to examples that are nice and simple and straightforward that could be used for a walkthrough of net driver design. thoughts? rday p.s. i'm already aware of the mass of documentation under Documentation/networking -- any pointers to online net driver design and tutorials would be appreciated. and, yes, i'm also digging through LDD3, https://lwn.net/Kernel/LDD3/. ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
