Date: Thu, 24 Aug 2017 21:16:50 -0600 From: Warner Losh <imp@bsdimp.com> To: Jim Harris <jim.harris@gmail.com> Cc: Kinjal Patel <Kinjal.Patel@taec.toshiba.com>, "freebsd-drivers@freebsd.org" <freebsd-drivers@freebsd.org> Subject: Re: NVMe driver init sequence Message-ID: <CANCZdfq=3Xhu84tiMDg6GHJaM4Qu9oJTvBmF-5=FqUUNfBf2HQ@mail.gmail.com> In-Reply-To: <CAJP=Hc-=imnaN37y3YBExU0s0uW24WPqdAQkRL9A343svGyZvw@mail.gmail.com> References: <FF0EFEF230D6F6409EC6998DBF26B91640483138@EXMAIL1.taec.toshiba.com> <CANCZdfqt-35BmCS61v_LX2R4%2BoPNHYF_rsFqeCg3=AyD6ujw4w@mail.gmail.com> <FF0EFEF230D6F6409EC6998DBF26B916404837F8@EXMAIL1.taec.toshiba.com> <CAJP=Hc-=imnaN37y3YBExU0s0uW24WPqdAQkRL9A343svGyZvw@mail.gmail.com>
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Greetings, I've just committed r322872 which implements this, with a slightly tweaked comment. Warner On Fri, Aug 18, 2017 at 4:09 PM, Jim Harris <jim.harris@gmail.com> wrote: > On Fri, Aug 18, 2017 at 2:04 PM, Kinjal Patel > <Kinjal.Patel@taec.toshiba.com> wrote: > > Created a bug #22166 (https://bugs.freebsd.org/bugzilla/show_bug.cgi?id= > 221616) > > Updated the description and patch to it. > > > > Regards, > > Kinjal Patel > > > > From: Kinjal Patel > > Sent: Friday, August 18, 2017 1:51 PM > > To: 'Warner Losh' > > Cc: freebsd-drivers@freebsd.org > > Subject: RE: NVMe driver init sequence > > > > Here is a the change I propose. This will make the init sequence right. > > Looks good to me. > > > > > Index: sys/dev/nvme/nvme.c > > =================================================================== > > --- sys/dev/nvme/nvme.c (revision 322672) > > +++ sys/dev/nvme/nvme.c (working copy) > > @@ -253,6 +253,9 @@ > > return (status); > > } > > > > + /* make device bus-master before attempting to enable controller */ > > + pci_enable_busmaster(dev); > > + > > /* > > * Reset controller twice to ensure we do a transition from > cc.en==1 > > * to cc.en==0. This is because we don't really know what > status > > @@ -270,8 +273,6 @@ > > return (status); > > } > > > > - pci_enable_busmaster(dev); > > - > > ctrlr->config_hook.ich_func = nvme_ctrlr_start_config_hook; > > ctrlr->config_hook.ich_arg = ctrlr; > > > > > > > > regards, > > Kinjal Patel > > > > From: wlosh@bsdimp.com<mailto:wlosh@bsdimp.com> [mailto:wlosh@bsdimp.com] > On Behalf Of Warner Losh > > Sent: Thursday, August 17, 2017 3:10 PM > > To: Kinjal Patel > > Cc: freebsd-drivers@freebsd.org<mailto:freebsd-drivers@freebsd.org> > > Subject: Re: NVMe driver init sequence > > > > This sounds right to me.... Most BIOSes seem to enable BME=1. > > > > Warner > > > > On Thu, Aug 17, 2017 at 2:45 PM, Kinjal Patel < > Kinjal.Patel@taec.toshiba.com<mailto:Kinjal.Patel@taec.toshiba.com>> > wrote: > > Hi, > > > > I have a query on NVMe driver init sequence in FreeBSD 10.3(stable). > > > > The driver init sequence is, > > > > 1) Enable controller (CC.EN=1) > > > > 2) Wait for controller ready (CSTS.RDY=1) > > > > 3) Set PCI bus master enable (BME=1) > > > > As per NVMe spec, when NVMe controller becomes ready it has to process > command. > > > > "Enable (EN): When set to '1', then the controller shall process > commands based on Submission Queue Tail doorbell writes" > > > > And per PCI Express spec when BME is not set, the PCI Express Function > is not allowed to issue any Memory or I/O requests. > > "Bus Master Enable - Controls the ability of a PCI Express Endpoint to > issue Memory95 and I/O Read/Write Requests, and > > the ability of a Root or Switch Port to forward Memory and I/O > Read/Write Requests in the Upstream direction" > > > > Enabling controller before setting BME=1 is violation of spec, as > controller has to accept commands but BME is prerequisite for that. > > > > The Linux device driver init sequence is, > > > > 1) Set PCI bus master enable (BME=1) > > > > 2) Enable Controller (CC.EN=1) > > > > 3) Wait for controller ready (CSTS.RDY=1) > > > > The FreeBSD NVMe driver sequence should be changed to set BME=1 before > attempting to enable controller. > > > > > > Regards, > > Kinjal Patel > > _______________________________________________ > > freebsd-drivers@freebsd.org<mailto:freebsd-drivers@freebsd.org> mailing > list > > https://lists.freebsd.org/mailman/listinfo/freebsd-drivers > > To unsubscribe, send any mail to "freebsd-drivers-unsubscribe@ > freebsd.org<mailto:freebsd-drivers-unsubscribe@freebsd.org>" > > > > _______________________________________________ > > freebsd-drivers@freebsd.org mailing list > > https://lists.freebsd.org/mailman/listinfo/freebsd-drivers > > To unsubscribe, send any mail to "freebsd-drivers-unsubscribe@ > freebsd.org" >
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