Date: Mon, 23 Jun 2014 11:38:59 -0600 From: Warner Losh <imp@bsdimp.com> To: John Baldwin <jhb@FreeBSD.org> Cc: Emeric POUPON <emeric.poupon@arkoon-netasq.com>, freebsd-arch@freebsd.org Subject: Re: How to properly handle several fonctions provided by the Winbond SuperIO chip? Message-ID: <0C33F78B-60F2-41A5-92AD-C002EACE312E@bsdimp.com> In-Reply-To: <201406230956.48220.jhb@freebsd.org> References: <1118241087.138096.1403180509132.JavaMail.zimbra@arkoon-netasq.com> <201406190919.04443.jhb@freebsd.org> <750618593.166408.1403191319583.JavaMail.zimbra@arkoon-netasq.com> <201406230956.48220.jhb@freebsd.org>
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--Apple-Mail=_0DF483F6-486F-4E8F-B911-A4D2911C4AAF Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=windows-1252 On Jun 23, 2014, at 7:56 AM, John Baldwin <jhb@FreeBSD.org> wrote: > On Thursday, June 19, 2014 11:21:59 am Emeric POUPON wrote: >> Thanks for your answer! >>=20 >> I was thinking about calling some parent device functions from the = children=20 > devices in order to perform IO accesses. >> But I imagine it would be "better" to expose a kind of bus interface = from=20 > the main driver? >> However, I'm not sure the extra work induced is worth it. What do you = think? >=20 > I think it's fine to have them call each other directly if they are = going to=20 > all live in the same module. =46rom a pure design point of view, having helpers might be slightly = better. However, given the specialized nature of SuperIO chips, you=92ll likely = get very little reuse of out the more complicated design, so John=92s suggestion = will be a big win. The only time you=92ll likely need to get the parent involved is for = =93shared access=94 situations (some SuperIO chips have banked registers, and you have to = have some kind of locking in place to access them, even if the locking is = done with a grab/ungrab bus paradigm). Warner --Apple-Mail=_0DF483F6-486F-4E8F-B911-A4D2911C4AAF Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP using GPGMail -----BEGIN PGP SIGNATURE----- Comment: GPGTools - https://gpgtools.org iQIcBAEBCgAGBQJTqGY0AAoJEGwc0Sh9sBEApr8P/33x5pj34CPTKRIxyYxY2S4m Kc+8UpLfdtNJGfMrfkApjiS+QTDYpeRCuMs1y0yM8fFgleqEONdbxmIi2CQBHIRJ Lo22mNAQQc4HwwbgPZ+lI/uiktMhdIUyaSOqcYtZCEN+Ipy+ukiOevvZwhlRovv7 Zi6QbuafJ4Tp1sjH3WlBfjlD8ZF6mdw9hJ5GrGSr2/WQgH/9Blreb2F4xHhANibj +7Vldp9rx2ZHxRz6aSfg2JITzAs5KT9v5AoW/MnUHt9xYvSmVcQY35bIttVJ4ujm GYyilrToEAa7F5xRDYPrhg8AiyIWkL2UU4lCkVvMBQjJ45hXxXBZvRPwNasSXYMN 7a4fzBO+jaBRZkVN8RxZt6XTCTP7a3Qws2AdswL0vKi8k5r0ygQ5nR+c9/HDJzS2 jNyjOs0mUqIFjXCIY06D+NBbL72IYw5l+n/9xMA17qsqcg3VOqfu+fxlKzRaAhUV mwCagAXL0P1c5dj7pXyBVRIL9Z7bhZAfLv1R1KAREde7ioFKmDNeJIaIYCcrIHWX Jh6pSw1ukBGAHXzI9D3XhIQ40ivCDwYh5ZvSHye0XRKTvhusNOj2Kxda4R4t/Lym osJjZq5XjWWazdEb0P0b68N7QU2LsYAgg2erJNUjSJAhM5at9CAECw+9tMT2DA8c utLxlgFWR+V7LGHsUSJv =Wo6a -----END PGP SIGNATURE----- --Apple-Mail=_0DF483F6-486F-4E8F-B911-A4D2911C4AAF--
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