Hello Kim, Kim Phillips wrote: > On Tue, 18 Aug 2009 15:23:47 +0200 > Heiko Schocher <h...@denx.de> wrote: > >> Hello Kim, > > Hello Heiko, sorry for the late reply,
No problem, thanks for your response! >> I actually work on an u-boot mpc8321 port (mostly identical with the kmeter1 >> port already in mainline), and I have to set the LCRR (Clock Ratio Register >> Reference Manual 10.3.1.14). As I see in >> >> cpu/mpc83xx/cpu_init.c cpu_init_f() >> >> this is done while running from flash. Hmm... the Reference manual >> says in chapter 10.3.1.14 page 474: >> >> NOTE >> For proper operation of the system, this register setting must not be altered >> while local bus memories or devices are being accessed. Special care needs >> to be taken when running instructions from an local bus controller memory. >> >> Hmm... >> >> On my board (and for example on the MPC832XEMDS) the flash is connected >> to the localbus ... and this register setting is done, while >> running from flash ... Hmm.. is this safe? > > yeah, I'm not quite sure how that works myself! :-( >> I only can set the LCRR register succesfully on my board port, if >> I set the LCRR_DBYP bit in the CONFIG_SYS_LCRR define, without it >> I couldn;t run u-boot (with it, it works fine) >> >> Unfortunately this LCRR_DBYP bit (0x80000000) is not documented in >> the MPC8323ERM ... there, it is just marked as reserved (and set >> to 1 on reset) >> >> So, it is ok, just to set this LCRR_DBYP bit? Or should the LCRR >> register only changed, if u-boot runs from ram? Or ...? > > I'd say set the bit - my guess it the bit always existed, but it just > got documented in later parts' docs. E.g, this is from the mpc8315 > documentation: > > 0 PBYP PLL bypass. This bit should be set when using low bus clock > frequencies (66 MHz or lower). > When in PLL bypass mode, incoming data is captured in the middle of > the bus clock cycle. > 0 The PLL is enabled. > 1 The PLL is bypassed. Thanks, I found this bit also in the 8360 Reference Manual. bye Heiko -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
