Date: Tue, 19 Apr 2016 16:41:22 -0400 From: Patrick Kelsey <pkelsey@freebsd.org> To: Adrian Chadd <adrian.chadd@gmail.com> Cc: Ian Lepore <ian@freebsd.org>, Juli Mallett <juli@clockworksquid.com>, Ruslan Bukin <br@freebsd.org>, "src-committers@freebsd.org" <src-committers@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "svn-src-head@freebsd.org" <svn-src-head@freebsd.org> Subject: Re: svn commit: r298274 - head/sys/dev/spibus Message-ID: <CAD44qMWJeTNuXS%2BB1ecJUFN63dweYZRKKG4Ek7kxMk-Mme7=%2BQ@mail.gmail.com> In-Reply-To: <CAJ-Vmo=GiP_NXfBz5ZsJkBm8Ypm-t0udZRqX9BkTa0KuC1bvrw@mail.gmail.com> References: <201604191539.u3JFdkHx048678@repo.freebsd.org> <CAJ-VmonyZR-CiPxceAvVzxDjL7WXDAix-Pmj2RRqp%2B9gj3u0hA@mail.gmail.com> <20160419171243.GA30453@bsdpad.com> <CACVs6=_pN9VAz1kkQQAL-ftKof%2Bkkn5MgxDP1kWj9kM-x=AzbQ@mail.gmail.com> <1461097280.1232.34.camel@freebsd.org> <CAD44qMV1bRA9USafKLSdKv8CcES34G8Kbt54OspaAA_Xdb07xg@mail.gmail.com> <CAJ-Vmo=GiP_NXfBz5ZsJkBm8Ypm-t0udZRqX9BkTa0KuC1bvrw@mail.gmail.com>
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On Tue, Apr 19, 2016 at 4:38 PM, Adrian Chadd <adrian.chadd@gmail.com> wrote: > On 19 April 2016 at 13:37, Patrick Kelsey <pkelsey@freebsd.org> wrote: > > > > > > On Tue, Apr 19, 2016 at 4:21 PM, Ian Lepore <ian@freebsd.org> wrote: > >> > >> On Tue, 2016-04-19 at 13:17 -0700, Juli Mallett wrote: > >> > Patrick Kelsey offered an mmcspi driver for FreeBSD, but nobody > >> > seemed > >> > interested. I know of one proprietary branch of FreeBSD using it. > >> > You might poke him if you want to know how he dealt with this, and if > >> > you want to commit his driver. > >> > > >> > >> Patrick is a committer, maybe he should just commit it. :) > > > > > > What I believe originally held up that driver being committed (by others > - > > this was before my commit bit) was that I relied on some out-of-tree > spibus > > changes Luiz had made (as I recall, mainly being able to reserve the SPI > bus > > for multiple transactions), and getting those into the tree would have > > required updating/testing other existing SPI drivers, based on feedback I > > received at the time. All I had was the RB450G that I developed and > tested > > the driver with, so I really couldn't address that issue, and then work > took > > me in some other direction entirely. Some or all of these spibus changes > > that I relied on might now be in the tree, I'm not sure offhand. I am > sure > > though that a huge stack of other things I need to get through has > > chronically kept me from updating that driver to current and retesting. > > > > When I wrote that driver, I put a lot of effort into testing it against > as > > many different cards as I could obtain at the time - I believe 30 or so > in > > total, all the details are in the code that was posted to the list back > > then. I encountered a number of strange/unexpected behaviors in that > set of > > cards, and all of that hard-won knowledge is in that driver, including a > > much less complex fix for a shifted-response-data issue than you will > see if > > you look at the Linux mmcpsi driver (as I recall, the Linux driver has > code > > to arbitrarily bit-shift card response data, and to detect when that > should > > be done, but it turns out that can be avoided entirely by inserting idle > > cycles in the right place when sending the command). > > Well, we should add the SPI bus reservation code and churn stuff as > needed. I think that'd be a great addition. > > Do you have a patchset somewhere? > > Just going from memory here - there is what I posted to the list, then at some point Luiz took a stab at updating it to then-current (I should have a copy of those somewhere - not sure where else they went, if anywhere), and beyond that, I think there's a harmless but unnecessary conditional in the original code that could be removed. -Patrick
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