Ticket #12589 (closed defect: fixed)

Opened 19 months ago

Last modified 19 months ago

XO-4: second PJ4 core and MM core need to be powered off.

Reported by: pgf Owned by: Quozl
Priority: high Milestone: 4-firmware
Component: ofw - open firmware Version: Development source as of this date
Keywords: Cc:
Action Needed: no action Verified: no
Deployments affected: Blocked By:


currently the two unused cores are left in reset (their default state) while the system is running.

it will save considerable power, and reduce the operating temperature, to release them from reset and power them down.

the following OFW lines accomplish this:

        e320f003 0 instruction!
        2000.0062 200 pmua!
        2000.0062 204 pmua!
        150 pmua@ 0600.0000 or 150 pmua!

the above is a distillation of this recipe from andres and mitch:

Here's the recipe for turning off cores.

\ Check that all 3 cores are currently powered (bits 8,9,10)
ok 90 pmua@ .

ok e320f003 0 instruction!          \ Put a WFI in the reset vector

To disable the low power core:

ok 2000.0062 204 pmua!    \ power down MMCore's L1, SRAM, core, and
                          \ core clock when core enters WFI
ok 150 pmua@ 0400.0000 or 150 pmua!   \ unreset MMCore
ok 90 pmua@ .     \ check core status                    
3c1               \ bit 10 is now unset (MMCore powered off)

To disable the second high power core (MP2):

ok 2000.0062 200 pmua!    \ power down MP2's L1, etc w/ WFI
ok 150 pmua@ 0200.0000 or 150 pmua! \ Unreset MPCORE2
ok 90 pmua@ .   \ check core status
1f1             \ bit 9 is now unset (MP2 powered off)

we should apply this (with comments) somewhere appropriate in OFW. it needn't be in cforth.

Change History

Changed 19 months ago by dsd

  • priority changed from normal to high

Changed 19 months ago by Quozl

  • owner changed from wmb@… to Quozl
  • status changed from new to assigned

Changed 19 months ago by Quozl

  • next_action changed from code to package

Fixed in  svn 3585.

Changed 19 months ago by dsd

  • next_action changed from package to test in build

Test in Q7B23.

Changed 19 months ago by Quozl

  • status changed from assigned to closed
  • next_action changed from test in build to no action
  • resolution set to fixed

Is in Q7B23.

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