Hi Tom,
On Mon, Dec 10, 2012 at 9:05 AM, Tom Warren twarren.nvidia@gmail.com wrote:
Simon,
On Sat, Dec 8, 2012 at 1:00 PM, Simon Glass sjg@chromium.org wrote:
Hi,
On Tue, Dec 4, 2012 at 2:41 PM, Stephen Warren swarren@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.
Sounds good, thanks. It would be good to get this in.
Regards, Simon
Thanks,
Tom
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