Hello.
On 23-10-2011 15:10, Nori, Sekhar wrote:
EPCPR register and PDCTL.EPCGOOD bit exist only on DaVinci DM644x and DM35x,
so do not try to poll EPCPR and set PDCTL.EPCGOOD on the other SoCs -- it would
lead to lock up if some power domain hasn't been powered up by this time (which
hasn't happened yet on any board, it seems).
Signed-off-by: Sergei Shtylyov<sshtyl...@ru.mvista.com>
Firstly, sorry about feedback this late. I was involved in
the bring-up of a new TI SoC which took much more of my
time than I anticipated.
So, I looked at power domain support for each of the 6
DaVinci SoCs we support (don't have the specifications
But we support more than 6 SoCs... :-)
for tnetv107x; and code does not have evidence of a separate
DSP power domain).
It looks like none of the SoCs except DM6446 actually support
powering down the DSP power domain.
DM6467, DM355, DM365 all have a single "Always ON" power
domain. DM355 specification actually talks about EPCPR
and EPCGOOD but that's probably due to copy paste from
DM644x specification than anything else.
OMAP-L137 and OMAP-L138 have additional power domains for DSP
and Shared RAM, but do not support powering them down.
I haven't found such words in either OMAP-L137 or OMAP-L138 datasheets.
What they say is:
<<
- On PSC0 PD1/PD_DSP Domain: Controls the sleep state for DSP L1 and L2 Memories
- On PSC1 PD1/PD_SHRAM Domain: Controls the sleep state for the 128K Shared RAM
>>
Although "OMAP-L137 Application Processor System Reference Guide" indeed
said that powering off domain 1 is not supported.
Actually, I was able to power down DSP/shared RAM domains on DA830 (at
least the state transition completed); although the domains were on, at least
after U-Boot. That's how I checked that the code powering up these domains
actually locks up on this SoC.
So, looks like the only SoC where PDSTAT might indicate a powered
down domain is DM644x and existing code to looks alright for
that SoC.
At this time, it would be better to leave the code as-is and
revisit it if/when a new SoC with programmable power domain
support comes along.
At least on DA830 power domains appear to be programmable. So I'd still
like the patch to be applied (I could drop DM355 check though).
Thanks,
Sekhar
WBR, Sergei
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