From: tony@atomide.com (Tony Lindgren)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: /proc/atags: Export also for DT
Date: Wed, 28 Jan 2015 07:48:24 -0800 [thread overview]
Message-ID: <20150128154824.GM28663@atomide.com> (raw)
In-Reply-To: <201501281647.34477@pali>
* Pali Roh?r <pali.rohar@gmail.com> [150128 07:50]:
> On Wednesday 28 January 2015 16:39:13 Tony Lindgren wrote:
> > * Nicolas Pitre <nico@fluxnic.net> [150128 06:37]:
> > > On Wed, 28 Jan 2015, Pali Roh?r wrote:
> > > > On Wednesday 28 January 2015 01:50:33 Tony Lindgren wrote:
> > > > > On omaps, the bootrom passes the bootreason in r1 to the
> > > > > bootloader that can do whatever it wants with it. We
> > > > > could maybe pass it in the kernel cmdline to the
> > > > > watchdog driver for user space?
> > > >
> > > > Not truth for N900. Bootreason depends on PRM_RSTST omap
> > > > register, state of vbat charger pins, time how long was
> > > > power key pressed, R&D data stored in CAL partition and
> > > > other undocumented registers for omap HS devices. I
> > > > already tried to implement at least some subset of it in
> > > > userspace (or kernel), but it is impossible because NOLO
> > > > bootloader clear status of PRM_RSTST register.
> > > >
> > > > There is also copy of PRM_RSTST register stored at address
> > > > 0x4020FFB8 (tracing data) but that address is rewritten
> > > > (probably by kernel), so we really cannot implement
> > > > reading bootreason in kernel.
> > > >
> > > > But in early stage in uboot it is possible to read
> > > > 0x4020FFB8 address and get some part of bootreason. But
> > > > still PRM_RSTST is not enough!
> > > >
> > > > I would be happy if DT kernel can export /proc/atags file
> > > > with ATAGs passed by bootloader. It would be enough for
> > > > me. In userspace I can parse content and do what is
> > > > needed.
> > >
> > > What about defining a DT boot reason property instead?
> > > Maybe it already exists? If not, it's something that could
> > > certainly be generically used on other platforms too.
> > >
> > > Converting the special ATAG into its standard DT equivalent
> > > would then be trivial and much cleaner overall.
> >
> > Sounds good to me as then we don't have to add any legacy
> > custom Nokia specific atag. And it won't prevent us from
> > adding a generic ATAG_BOOTREASON if really needed.
>
> And what would new atag ATAG_BOOTREASON solve for Nokia N900?
> Nothing.
Right, so probably no need to add it then :) But what Nico is
saying we can translate the Nokia custom bootreason to a
standard DT property if I'm reading right.
Regards,
Tony
next prev parent reply other threads:[~2015-01-28 15:48 UTC|newest]
Thread overview: 99+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-18 16:54 [PATCH] ARM: /proc/cpuinfo: Use DT machine name when possible Pali Rohár
2014-06-18 19:01 ` Russell King - ARM Linux
2014-06-18 19:09 ` Pali Rohár
2014-06-18 19:59 ` Russell King - ARM Linux
2014-06-19 8:21 ` Pavel Machek
2014-07-11 19:31 ` Pavel Machek
2014-06-18 19:07 ` Rob Herring
2014-06-18 19:22 ` Pali Rohár
2014-06-18 20:00 ` Russell King - ARM Linux
2014-06-18 20:20 ` Pali Rohár
2014-06-18 21:53 ` Fabio Estevam
2014-11-24 22:16 ` Pali Rohár
2014-06-18 20:46 ` Rob Herring
2014-06-18 21:47 ` Russell King - ARM Linux
2014-06-18 22:27 ` Rob Herring
2014-06-18 23:07 ` Russell King - ARM Linux
2014-11-24 22:19 ` Pali Rohár
2014-12-04 0:33 ` Rob Herring
2014-12-04 0:48 ` Pali Rohár
2014-12-04 16:49 ` Rob Herring
2014-12-04 17:57 ` Pali Rohár
2014-12-04 18:10 ` Rob Herring
2015-01-26 19:09 ` [PATCH] ARM: /proc/cpuinfo: DT: Add support for Revision Pali Rohár
2015-01-26 20:22 ` Rob Herring
2015-01-30 14:14 ` Pali Rohár
2015-01-30 21:03 ` Rob Herring
2015-02-27 15:45 ` Pali Rohár
2015-02-27 15:55 ` [PATCH v2 0/2] " Pali Rohár
2015-02-27 15:55 ` [PATCH v2 1/2] arm: devtree: Set system_rev from DT revision Pali Rohár
2015-02-27 15:55 ` [PATCH v2 2/2] arm: boot: convert ATAG_REVISION to DT revision field Pali Rohár
2015-03-02 11:28 ` [PATCH v2 0/2] ARM: /proc/cpuinfo: DT: Add support for Revision Pavel Machek
2015-03-16 15:44 ` Tony Lindgren
2015-03-16 16:14 ` Russell King - ARM Linux
2015-03-16 16:43 ` Nicolas Pitre
2015-03-16 19:21 ` Russell King - ARM Linux
2015-03-16 18:10 ` Tony Lindgren
2015-03-16 19:59 ` Russell King - ARM Linux
2015-03-16 20:54 ` Pali Rohár
2015-03-16 20:59 ` Tony Lindgren
2015-01-26 22:34 ` [PATCH] " Andreas Färber
2015-02-27 15:56 ` Pali Rohár
2015-01-26 19:16 ` [PATCH] ARM: /proc/atags: Export also for DT Pali Rohár
2015-01-26 20:33 ` Rob Herring
2015-01-27 13:21 ` Pavel Machek
2015-01-27 14:16 ` Rob Herring
2015-01-27 14:24 ` Pavel Machek
2015-01-27 14:32 ` Pali Rohár
2015-01-27 17:48 ` Russell King - ARM Linux
2015-01-27 20:03 ` Nicolas Pitre
2015-01-27 21:09 ` Russell King - ARM Linux
2015-01-27 21:34 ` Nicolas Pitre
2015-01-27 21:58 ` Nicolas Pitre
2015-01-27 22:33 ` Russell King - ARM Linux
2015-01-28 2:07 ` Nicolas Pitre
2015-01-28 6:21 ` Jean-Christophe PLAGNIOL-VILLARD
2015-01-28 7:19 ` Pavel Machek
2015-01-28 8:06 ` Jean-Christophe PLAGNIOL-VILLARD
2015-01-28 8:25 ` Pavel Machek
2015-01-28 7:18 ` Pavel Machek
2015-01-28 13:38 ` Pali Rohár
2015-01-27 23:10 ` Pavel Machek
2015-01-28 0:50 ` Tony Lindgren
2015-01-28 13:58 ` Pali Rohár
2015-01-28 14:33 ` Nicolas Pitre
2015-01-28 15:39 ` Tony Lindgren
2015-01-28 15:47 ` Pali Rohár
2015-01-28 15:48 ` Tony Lindgren [this message]
2015-01-28 16:31 ` Jason Cooper
2015-01-28 15:57 ` Rob Herring
2015-01-28 16:13 ` Russell King - ARM Linux
2015-01-28 16:19 ` Will Deacon
2015-01-28 17:01 ` Russell King - ARM Linux
2015-01-28 17:29 ` Russell King - ARM Linux
2015-01-28 17:18 ` Pali Rohár
2015-01-28 18:00 ` Jean-Christophe PLAGNIOL-VILLARD
2015-01-28 19:33 ` Pali Rohár
2015-01-28 18:03 ` Pavel Machek
2015-01-28 19:27 ` Arnd Bergmann
2015-01-28 14:46 ` Jean-Christophe PLAGNIOL-VILLARD
2015-01-27 19:40 ` Nicolas Pitre
2015-01-26 20:37 ` Russell King - ARM Linux
2015-01-26 20:44 ` Pali Rohár
2014-12-04 19:00 ` [PATCH] ARM: /proc/cpuinfo: Use DT machine name when possible Pali Rohár
2014-12-04 10:59 ` Russell King - ARM Linux
2014-06-18 21:10 ` Aaro Koskinen
2014-07-11 19:28 ` Pavel Machek
2014-11-24 22:21 ` Pali Rohár
2014-09-05 11:38 ` Pali Rohár
2014-09-05 12:13 ` Russell King - ARM Linux
2014-09-10 12:46 ` Pavel Machek
2014-11-24 22:23 ` Pali Rohár
2014-09-05 13:45 ` Mark Rutland
2014-09-05 13:52 ` Pali Rohár
2014-09-05 13:58 ` Mark Rutland
2014-11-24 22:25 ` Pali Rohár
2014-09-05 13:58 ` Fabio Estevam
2014-11-24 22:27 ` Pali Rohár
2014-09-06 15:34 ` Andreas Färber
2014-11-24 22:29 ` Pali Rohár
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