Date: Thu, 21 Jan 2016 19:35:10 -0800 From: Adrian Chadd <adrian.chadd@gmail.com> To: Stanislav Galabov <sgalabov@gmail.com> Cc: Warner Losh <imp@bsdimp.com>, "freebsd-arm@freebsd.org" <freebsd-arm@freebsd.org>, "freebsd-mips@freebsd.org" <freebsd-mips@freebsd.org> Subject: Re: SPI geom_flashmap/fdt_slicer support, FDT 'resets=' support and a move of ohci_fdt.c Message-ID: <CAJ-Vmo=DcfSXsuLUpcMvogjWNmNrniNsPxshhmHcGoWOxWM=CQ@mail.gmail.com> In-Reply-To: <2AB9D6E1-BFF8-4EEE-B366-C980B72C4779@gmail.com> References: <B4B24B7D-B3EE-4F37-9E89-24FF17294C70@gmail.com> <CANCZdfrt-EdzFuXFSP2sTAX2vxP_RKAamKgUeL0u7hZYxeOF_A@mail.gmail.com> <2AB9D6E1-BFF8-4EEE-B366-C980B72C4779@gmail.com>
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On 18 January 2016 at 06:49, Stanislav Galabov <sgalabov@gmail.com> wrote: > Hi Warner, > > I was thinking resets could help in general, not specifically in the case= of trying to implement a generic ohci_fdt driver. > > As I already mentioned to you off-list (and in order for this message to = possibly make some more sense), I saw that Linux makes use of the =E2=80=98= resets=E2=80=99 property and looked at the documentation for it: > https://github.com/torvalds/linux/blob/master/Documentation/devicetree/bi= ndings/reset/reset.txt <https://github.com/torvalds/linux/blob/master/Docum= entation/devicetree/bindings/reset/reset.txt> > > For example, with the work I am currently doing on Ralink/Mediatek suppor= t, I have over 10 different chips in the same family, that have very simila= r peripheral blocks, but their clocks and resets are controlled via differe= nt bits in one of the SysCtl registers (the register itself is at the same = offset within the SysCtl block of each chip). So I may have chip X which ha= s its USB (for example) reset controlled by bit 10 and chip Y with USB rese= t controlled by bit 12. > > So being able to write something like: > resets =3D <&sysctl 10>; > or > resets =3D <&sysctl 11>; > > in my dts/dtsi files helps me immensely, instead of having to check what = chip I am running on and based on that use a different register layout=E2= =80=A6 > Then, if I wanted to (de)assert reset for a peripheral block that has thi= s property defined I=E2=80=99d just do fdt_reset_(de)assert_all(dev), where= dev is the device_t for the peripheral in question. This would (de)assert = all reset pins associated with the peripheral. > > The same is the case for clock control (gating) in the Ralink/Mediatek So= Cs and this is the main reason I used fdt_clock that is already in sys/dev/= fdt and then thought about implementing the fdt_reset based on it. > > I hope this clarifies a bit my reason for submitting the fdt_reset patch. This seems fine to me. Hm. Ian? Any comments? -a > Best wishes > Stanislav > >> On Jan 18, 2016, at 02:04, Warner Losh <imp@bsdimp.com> wrote: >> >> I don't see how resets help. Maybe I missed where it was documented, cou= ld you send that to me? >> >> Even with that, it seems that a generic ohci_fdt driver isn't possible. >> >> Warner >> >> On Thu, Jan 14, 2016 at 2:01 AM, Stanislav Galabov <sgalabov@gmail.com <= mailto:sgalabov@gmail.com>> wrote: >> Hi all, >> >> First off, sorry for the cross-post, I wasn=E2=80=99t very sure where th= is should go=E2=80=A6 >> >> I=E2=80=99ve created 3 PRs, which enable some functionality that my work= on Ralink/Mediatek SoCs would benefit from. >> >> 1. https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D206227 <https://b= ugs.freebsd.org/bugzilla/show_bug.cgi?id=3D206227> >> - This enables geom_flashmap and fdt_slicer support for SPI flash chips = supported by the mx25l driver (sys/dev/flash/mx25l.c) >> >> 2. https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D206228 <https://b= ugs.freebsd.org/bugzilla/show_bug.cgi?id=3D206228> >> - This adds support for FDT =E2=80=98resets=3D=E2=80=99 property in much= the same way as ian@=E2=80=99s sys/dev/fdt/fdt_clock* supports FDT =E2=80= =98clocks=3D=E2=80=98 property. In fact this work is basically a modified v= ersion of fdt_clock* :-) >> >> 3. https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D206229 <https://b= ugs.freebsd.org/bugzilla/show_bug.cgi?id=3D206229> >> - This simply moves the at91 specific sys/dev/usb/controller/ohci_fdt.c = to sys/dev/usb/controller/at91ohci_fdt.c (and changes the filename in sys/a= rm/at91/files.at91 as well). The current naming is misleading IMHO and also= , I have some (vague-ish) plans to see if I can implement generic ohci_fdt = and ehci_fdt based on dwc_otg_fdt, so that systems with standard ehci/ohci = controllers can reuse these. >> >> Patches are attached to the PRs. >> >> I would appreciate any feedback on the PRs and would also appreciate it = if someone could commit these if the proposed changes are appropriate. >> >> Best wishes, >> Stanislav >> _______________________________________________ >> freebsd-arm@freebsd.org <mailto:freebsd-arm@freebsd.org> mailing list >> https://lists.freebsd.org/mailman/listinfo/freebsd-arm <https://lists.fr= eebsd.org/mailman/listinfo/freebsd-arm> >> To unsubscribe, send any mail to "freebsd-arm-unsubscribe@freebsd.org <m= ailto:freebsd-arm-unsubscribe@freebsd.org>" >> > > _______________________________________________ > freebsd-arm@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-arm > To unsubscribe, send any mail to "freebsd-arm-unsubscribe@freebsd.org"
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