On Fri, 6 Feb 2009, Wolfgang Denk wrote: > Dear Guennadi Liakhovetski, > > In message <pine.lnx.4.64.0902061002160.4...@axis700.grange> you wrote: > > Upon power on i.MX31 enables most peripheral clocks, Linux disables the ones > > Why does U-Boot do that?
i.MX31 does that - the CPU, not U-Boot. I.e., this is the default power-on mode. > This is against U-Boot design guidelines which state that U-Boot shall > only activate such peripherals that it uses itself. > > > didn't use I2C, the clock would stay disabled. And U-Boot on imx31_phycore > > uses an I2C EEPROM for environment data. So, after a reboot U-Boot would be > > That's another area of bad design. Should we not change U-Boot such > that it places the environment in flash? Hm, no idea who and why decided to do that. I can only guess that this comes from the original BSPs somewhere, maybe they wanted to ship various EEPROM versions while keeping the same NOR, although both are probably hard-soldered on the CPU board (cannot recognise the eeprom, can be under the barcode label). And maybe they have some user-space tools of their own to access that EEPROM... no, not defending, just trying to guess what we might break if we switch. > BTW: What does "fir imx31_phycore to work after Linux reboot" mean? I > cannot parse that. Sorry, s/fir/fix/. Thanks Guennadi --- Guennadi Liakhovetski, Ph.D. DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-0 Fax: +49-8142-66989-80 Email: off...@denx.de _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
