[PATCH 5/5] arm: boot: store ATAGs structure into DT "/chosen/linux,atags" entry

Michael Trimarchi michael at amarulasolutions.com
Fri Nov 27 00:44:51 PST 2015


Hi

On Fri, Nov 27, 2015 at 9:38 AM, Pali Rohár <pali.rohar at gmail.com> wrote:
> On Thursday 26 November 2015 12:39:30 Tony Lindgren wrote:
>> Just to explore options.. How about make a minimal device driver that
>> just loads the atags blob from /lib/firmware and then shows it in
>> /proc/atags? Of course some checking on the atags should be done by
>> the driver..
>
> And who can dynamically create that blob file in /lib/firmware? If
> kernel does not export those atags (somehow) from bootloader, then
> userspace is not able to create that blob... cyclic problem.
>

Are those atags from bootloader fix or they change device by device. If they
are fixed they can be included in some firmware and get from the disk.

Michael

> So no, problem is that bootloader provides via custom atags dynamic
> information like: boot reason (how was device started, by rtc alarm? by
> reboot? by usb charger? by power button?), boot mode (should be enter
> into firmware update mode?, is this normal boot mode?), ... and those
> information are needed for some proprietary software (e.g. firmware
> upgrade/flash) but also by any other open source applications (based on
> usb charger we enter different runlevel -- for just only charging
> device).
>
> --
> Pali Rohár
> pali.rohar at gmail.com
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