On Wednesday 28 January 2015 16:39:13 Tony Lindgren wrote: > * Nicolas Pitre <n...@fluxnic.net> [150128 06:37]: > > On Wed, 28 Jan 2015, Pali Rohár 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. > > Regards, > > Tony
And what would new atag ATAG_BOOTREASON solve for Nokia N900? Nothing. -- Pali Rohár pali.ro...@gmail.com
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