* 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
