Date: Mon, 18 Jan 2016 16:49:10 +0200 From: Stanislav Galabov <sgalabov@gmail.com> To: Warner Losh <imp@bsdimp.com> Cc: Stanislav Galabov <sgalabov@gmail.com>, "freebsd-mips@freebsd.org" <freebsd-mips@freebsd.org>, "freebsd-arm@freebsd.org" <freebsd-arm@freebsd.org> Subject: Re: SPI geom_flashmap/fdt_slicer support, FDT 'resets=' support and a move of ohci_fdt.c Message-ID: <2AB9D6E1-BFF8-4EEE-B366-C980B72C4779@gmail.com> In-Reply-To: <CANCZdfrt-EdzFuXFSP2sTAX2vxP_RKAamKgUeL0u7hZYxeOF_A@mail.gmail.com> References: <B4B24B7D-B3EE-4F37-9E89-24FF17294C70@gmail.com> <CANCZdfrt-EdzFuXFSP2sTAX2vxP_RKAamKgUeL0u7hZYxeOF_A@mail.gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
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=98resets=E2=80=99 property and looked at the documentation for = it: = https://github.com/torvalds/linux/blob/master/Documentation/devicetree/bin= dings/reset/reset.txt = <https://github.com/torvalds/linux/blob/master/Documentation/devicetree/bi= ndings/reset/reset.txt> For example, with the work I am currently doing on Ralink/Mediatek = support, I have over 10 different chips in the same family, that have = very similar peripheral blocks, but their clocks and resets are = controlled via different 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 has its USB (for example) reset = controlled by bit 10 and chip Y with USB reset 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 = this 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 = SoCs 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. Best wishes Stanislav > On Jan 18, 2016, at 02:04, Warner Losh <imp@bsdimp.com> wrote: >=20 > I don't see how resets help. Maybe I missed where it was documented, = could you send that to me? >=20 > Even with that, it seems that a generic ohci_fdt driver isn't = possible. >=20 > Warner >=20 > On Thu, Jan 14, 2016 at 2:01 AM, Stanislav Galabov <sgalabov@gmail.com = <mailto:sgalabov@gmail.com>> wrote: > Hi all, >=20 > First off, sorry for the cross-post, I wasn=E2=80=99t very sure where = this should go=E2=80=A6 >=20 > I=E2=80=99ve created 3 PRs, which enable some functionality that my = work on Ralink/Mediatek SoCs would benefit from. >=20 > 1. https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D206227 = <https://bugs.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) >=20 > 2. https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D206228 = <https://bugs.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 version of fdt_clock* :-) >=20 > 3. https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D206229 = <https://bugs.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/arm/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. >=20 > Patches are attached to the PRs. >=20 > I would appreciate any feedback on the PRs and would also appreciate = it if someone could commit these if the proposed changes are = appropriate. >=20 > Best wishes, > Stanislav > _______________________________________________ > freebsd-arm@freebsd.org <mailto:freebsd-arm@freebsd.org> mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-arm = <https://lists.freebsd.org/mailman/listinfo/freebsd-arm>; > To unsubscribe, send any mail to "freebsd-arm-unsubscribe@freebsd.org = <mailto:freebsd-arm-unsubscribe@freebsd.org>" >=20
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?2AB9D6E1-BFF8-4EEE-B366-C980B72C4779>