Hi Wolfgang, 2017-11-27 22:21 GMT+09:00 Wolfgang Denk <w...@denx.de>: > Dear Masahiro, > > In message > <cak7lnarc-muprmhsisjtea9x6hprae9t9wgdbdfg2dysepc...@mail.gmail.com> you > wrote: >> >> When we talk about "relocation", two things are happening. >> >> [1] U-Boot proper copies itself to the very end of DRAM > > ...to the very end of DRAM minus space reserved for any memory > regions we want to reserver for / share with the Linux kernel > (video memory, log buffer, protected RAM, ...) > >> [2] Fix-up the global symbols >> >> In my opinion, only [2] is useful. > > This is your opinion, accepted. > I do not agree with this, i. e. I have a different opinion. > >> SPL initializes the DRAM, so it knows the base and size of DRAM. > > But it does not know the relocation address yet. As this is > dynamically computed, depending on environment variable settings, > moving this calculation into the SPL means the SPL must be capable to > read the environment. this pulls in a ton of code, and any > advantages you may have for falcon mode are damaged.
How precise do we need to compute this? Platforms may choose a reasonable fixed size for reserved memory. The end of memory minus 256KB, 512KB, or whatever as you like. >> The following is how the ideal boot loader would work. >> >> >> Requirement for U-Boot proper: >> U-Boot never changes the location by itself. > > This means you kill all the features that depend on this? Are there features that depend on two-time relocation? As I stated above, the calculation can be compromised to some extent. We may waste a small amount of memory by the rough calculation, but is it a big deal? > Best regards, > > Wolfgang Denk > > -- > DENX Software Engineering GmbH, Managing Director: Wolfgang Denk > HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany > Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: w...@denx.de > f u cn rd ths, itn tyg h myxbl cd. > _______________________________________________ > U-Boot mailing list > U-Boot@lists.denx.de > https://lists.denx.de/listinfo/u-boot -- Best Regards Masahiro Yamada _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot