From: Rob Herring <robh@kernel.org>
To: Brian Norris <computersforpeace@gmail.com>
Cc: devicetree@vger.kernel.org, Marek Vasut <marek.vasut@gmail.com>,
Richard Weinberger <richard@nod.at>,
Zhiqiang Hou <Zhiqiang.Hou@nxp.com>, NeilBrown <neilb@suse.com>,
Boris Brezillon <boris.brezillon@bootlin.com>,
linux-mtd@lists.infradead.org
Subject: Re: [PATCH] mtd: spi-nor: only apply reset hacks to broken hardware
Date: Tue, 7 Aug 2018 12:39:01 -0600 [thread overview]
Message-ID: <20180807183901.GB31722@rob-hp-laptop> (raw)
In-Reply-To: <20180731223550.GA60117@ban.mtv.corp.google.com>
On Tue, Jul 31, 2018 at 03:35:50PM -0700, Brian Norris wrote:
> Hi Neil, Boris,
>
> On Tue, Jul 31, 2018 at 10:12:55PM +0200, Boris Brezillon wrote:
> > On Tue, 31 Jul 2018 11:05:11 +1000
> > NeilBrown <neilb@suse.com> wrote:
> > > On Fri, Jul 27 2018, Boris Brezillon wrote:
> > > > On Fri, 27 Jul 2018 11:33:13 -0700
> > > > I'll leave Neil some time to review/test/comment on the patch before
> > > > queuing it, but it looks good to me.
> > >
> > > Thanks.
> > > I can confirm that if I apply this patch, my system won't reboot
> > > properly (as expected), and if I then add
> > >
> > > broken-flash-reset;
> > >
> > > to the jedec,spi-nor device, it starts functioning correctly again.
> > >
> > > I don't like the pejorative "broken", and it also suggests that a thing
> > > used to work, but something happened to break it - this is not
> > > accurate.
> > > I would prefer something like "reset-not-connected" which is an accurate
> > > description of the state of the hardware.
>
> One reason I didn't specifically say something like "not connected", is
> because IIUC it's actually *possible* to have a robust boot sequence
> without the RESET# pin -- e.g., if your boot ROM hardcoded a software
> reset command (just because it's not really standardized doesn't mean
> one can't do it).
Based on that, then it sounds like you need a specific compatible string
so you too can know how to s/w reset the device.
I guess you are assuming a bootloader didn't leave the flash in an
unknown addressing state?
Rob
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WARNING: multiple messages have this Message-ID (diff)
From: Rob Herring <robh@kernel.org>
To: Brian Norris <computersforpeace@gmail.com>
Cc: Boris Brezillon <boris.brezillon@bootlin.com>,
NeilBrown <neilb@suse.com>,
devicetree@vger.kernel.org, Richard Weinberger <richard@nod.at>,
Zhiqiang Hou <Zhiqiang.Hou@nxp.com>,
Marek Vasut <marek.vasut@gmail.com>,
linux-mtd@lists.infradead.org
Subject: Re: [PATCH] mtd: spi-nor: only apply reset hacks to broken hardware
Date: Tue, 7 Aug 2018 12:39:01 -0600 [thread overview]
Message-ID: <20180807183901.GB31722@rob-hp-laptop> (raw)
In-Reply-To: <20180731223550.GA60117@ban.mtv.corp.google.com>
On Tue, Jul 31, 2018 at 03:35:50PM -0700, Brian Norris wrote:
> Hi Neil, Boris,
>
> On Tue, Jul 31, 2018 at 10:12:55PM +0200, Boris Brezillon wrote:
> > On Tue, 31 Jul 2018 11:05:11 +1000
> > NeilBrown <neilb@suse.com> wrote:
> > > On Fri, Jul 27 2018, Boris Brezillon wrote:
> > > > On Fri, 27 Jul 2018 11:33:13 -0700
> > > > I'll leave Neil some time to review/test/comment on the patch before
> > > > queuing it, but it looks good to me.
> > >
> > > Thanks.
> > > I can confirm that if I apply this patch, my system won't reboot
> > > properly (as expected), and if I then add
> > >
> > > broken-flash-reset;
> > >
> > > to the jedec,spi-nor device, it starts functioning correctly again.
> > >
> > > I don't like the pejorative "broken", and it also suggests that a thing
> > > used to work, but something happened to break it - this is not
> > > accurate.
> > > I would prefer something like "reset-not-connected" which is an accurate
> > > description of the state of the hardware.
>
> One reason I didn't specifically say something like "not connected", is
> because IIUC it's actually *possible* to have a robust boot sequence
> without the RESET# pin -- e.g., if your boot ROM hardcoded a software
> reset command (just because it's not really standardized doesn't mean
> one can't do it).
Based on that, then it sounds like you need a specific compatible string
so you too can know how to s/w reset the device.
I guess you are assuming a bootloader didn't leave the flash in an
unknown addressing state?
Rob
next prev parent reply other threads:[~2018-08-07 18:39 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-27 18:33 [PATCH] mtd: spi-nor: only apply reset hacks to broken hardware Brian Norris
2018-07-27 18:33 ` Brian Norris
2018-07-27 19:06 ` Guenter Roeck
2018-07-27 19:06 ` Guenter Roeck
2018-07-27 20:03 ` [PATCH] " Boris Brezillon
2018-07-27 20:03 ` Boris Brezillon
2018-07-31 1:05 ` NeilBrown
2018-07-31 1:05 ` NeilBrown
2018-07-31 20:12 ` Boris Brezillon
2018-07-31 20:12 ` Boris Brezillon
2018-07-31 22:15 ` Marek Vasut
2018-07-31 22:15 ` Marek Vasut
2018-08-01 0:40 ` NeilBrown
2018-08-01 0:40 ` NeilBrown
2018-08-01 8:24 ` Marek Vasut
2018-08-01 8:24 ` Marek Vasut
2018-07-31 22:35 ` Brian Norris
2018-07-31 22:35 ` Brian Norris
2018-08-01 1:06 ` NeilBrown
2018-08-01 1:06 ` NeilBrown
2018-08-07 18:39 ` Rob Herring [this message]
2018-08-07 18:39 ` Rob Herring
2018-08-07 19:22 ` Brian Norris
2018-08-07 19:22 ` Brian Norris
2018-08-01 0:38 ` NeilBrown
2018-08-01 0:38 ` NeilBrown
2018-08-01 7:15 ` Boris Brezillon
2018-08-01 7:15 ` Boris Brezillon
2018-08-07 18:33 ` Rob Herring
2018-08-07 18:33 ` Rob Herring
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