ppc/pnv: Implement the ChipTOD to Core transfer

One of the functions of the ChipTOD is to transfer TOD to the Core
(aka PC - Pervasive Core) timebase facility.

The ChipTOD can be programmed with a

ppc/pnv: Implement the ChipTOD to Core transfer

One of the functions of the ChipTOD is to transfer TOD to the Core
(aka PC - Pervasive Core) timebase facility.

The ChipTOD can be programmed with a target address to send the TOD
value to. The hardware implementation seems to perform this by
sending the TOD value to a SCOM address.

This implementation grabs the core directly and manipulates the
timebase facility state in the core. This is a hack, but it works
enough for now. A better implementation would implement the transfer
to the PnvCore xscom register and drive the timebase state machine
from there.

Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>

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ppc/pnv: Add POWER9/10 chiptod model

The ChipTOD (for Time-Of-Day) is a chip pervasive facility in IBM POWER
(powernv) processors that keeps a time of day clock.

In particular for this model are fa

ppc/pnv: Add POWER9/10 chiptod model

The ChipTOD (for Time-Of-Day) is a chip pervasive facility in IBM POWER
(powernv) processors that keeps a time of day clock.

In particular for this model are facilities that initialise and start
the time of day clock, and that synchronise that clock to cores on the
chip, and to other chips. In this way, all cores on all chips can
synchronise timebase (TB).

This model implements functionality sufficient to run the skiboot
chiptod synchronisation procedure (with the following core timebase
state machine implementation). It does not modify the TB in the cores
where the real hardware would, because the QEMU ppc timebase
implementation is always synchronised acros all cores.

Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>

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