Hi Yen, On Fri, Jan 13, 2012 at 2:04 PM, Yen Lin <ye...@nvidia.com> wrote: > Hi Simon, > > On Fri, 2012-01-13 at 11:34 -0800, Simon Glass wrote: >> Hi Stephen, >> >> [Yen please can you read this also?] >> >> On Tue, Jan 10, 2012 at 10:30 AM, Stephen Warren <swar...@nvidia.com> wrote: >> > On 12/26/2011 12:33 PM, Simon Glass wrote: >> >> From: Yen Lin <ye...@nvidia.com> >> >> >> >> Add code to set up the warm boot area in the Tegra CPU ready for a >> >> resume after suspend. >> >> >> >> Signed-off-by: Simon Glass <s...@chromium.org> >> > >> > How come Yen's S-o-b line is missing here? >> > >> > As a general comment on this patch, it contains a lot of structure >> > definitions and defines that should really be part of the clock module's >> > headers and similar; why not just included the clock headers and place >> > all the definitions in those headers if they aren't already there? >> >> Yes this bit of it got a pretty light review at the time and I was >> reluctant to press on the bitfields when that side of things was still >> up in the air. No functions exist to access these things and using the >> clk_rst.h header adds a mountain of ugly reg & OSC_FREQ_MASK) >> >> OSC_FREQ_SHIFT to the code. I am still uncomfortable with how this >> sort of thing is done in U-Boot. >> >> Also the AVP code cannot call functions in clock.c (they are in SDRAM >> which isn't on yet), so we need the structures or some sort of access >> there anyway. >> >> I will tidy up some low-hanging fruit in warmboot.c but don't know >> that I can do much with warmboot_avp.c. At least it isn't assembler >> anymore! >> >> But there a few questions here. Firstly it seems that it saves some >> memory speed info to scratch2 but never restores it. Then it restores >> CPU speed from scratch3 but I can't see where it saves it. Does Yen >> have any comments on that? Apparently it works because we have been >> using it, but... If it is saving things that are never restored I >> could dump that and reduce the code size. >> > > U-boot code saves sdram parameters to scratch2, scratch4, and scratch 24 > registers, so when system resumes, bootrom can restore sdram parameters > from these registers. > > The scratch3 register content was saved by kernel before suspend, and is > used by the warmboot code to restore PLLX settings.
Thanks for the info. On resume I do not see it using scratch2, 4 or 24 within U-Boot. Are those used in the kernel? I should add something to document this so the kernel people can match up when that side of it goes up stream. Regards, Simon > > > Regards, > > Yen > > > ----------------------------------------------------------------------------------- > This email message is for the sole use of the intended recipient(s) and may > contain > confidential information. Any unauthorized review, use, disclosure or > distribution > is prohibited. If you are not the intended recipient, please contact the > sender by > reply email and destroy all copies of the original message. > ----------------------------------------------------------------------------------- _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
