Simon, On Sat, Dec 8, 2012 at 1:00 PM, Simon Glass <s...@chromium.org> wrote: > Hi, > > On Tue, Dec 4, 2012 at 2:41 PM, Stephen Warren <swar...@wwwdotorg.org> wrote: >> On 12/04/2012 01:40 PM, Lucas Stach wrote: >>> Hi Tom, >>> >>> Am Dienstag, den 04.12.2012, 13:22 -0700 schrieb Tom Warren: >>> [...] >>>> >>>>> >>>>>> +#define V_NS16550_CLK 216000000 /* 216MHz >>>>>> (pllp_out0) */ >>>>> >>>>> I thought PLL_P ran at 408MHz on Tegra30? The kernel certainly sets it >>>>> up that way. >>>> >>>> See my previous reply. In the internal U-Boot repo I ported from, PLLP >>>> was initially set to 216MHz, then sped up to 408MHz. When this first >>>> round of patches is in, I can address going to 408MHz first thing. >>>> >>> Is running the PLL_P at 408MHz something which requires a lot of work? >>> If not, please do this and fold it into this patchset. It doesn't look >>> too nice adding things to upstream which have to be changed/removed >>> immediately after going in. >> >> Naively I'd have to agree here; it seems that programming the PLL for >> the correct rate would probably "just work" right from the outset? After >> all, if the code runs OK with the higher rate enabled a little later in >> boot, I see no reason it shouldn't run OK with that exact same rate the >> whole way through. > > From memory, the problem was originally that we wanted to be able to > configure the PLL speed at run time, because we we using both speeds. > Since T30 now apparently only uses 408MHz, it should be ok to set it > once and hard-code it. > > Regards, > Simon > Thanks. As I remember it, it was a user-config option for early T30 boards to run at 216MHz or 408MHz. The 408MHz PLLP change generated a lot of email traffic on what the best output clocks (pllp_out1 thru 4) would be for the various periphs, subclocks, etc.
When I did the original bringup for upstream U-Boot on my (older) Cardhu, I wanted to start at 216MHz first, then step up to 408MHz when I was at a stable point. Much like when I rebuilt my Mustang - I took it out around the block first, to be sure everything was working OK before I took it on the highway ;) I'm running OK at 408MHz on my Cardhu T33. I'll resubmit V3 of the patchset in the next day or so. Thanks, Tom >> >> _______________________________________________ >> U-Boot mailing list >> U-Boot@lists.denx.de >> http://lists.denx.de/mailman/listinfo/u-boot _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
