In the LS180, probably due to the implementation of a small RAM
with DFFs, some leaf of the clock tree (H-Tree) got heavily
loaded (around 80 DFFs sinks). Implement an option that allow
the leaf of the QuadTree to use three buffers instead of one.
The sinks are partitionned using their angle from the center
of the leaf (trigonometric direction). CChoose the bigger angle
gaps to perform the split.
* Change: In Cumulus/plugins.block.configuration.GaugeConf, in
getNearestHorizontalTrack() and getNearestVerticalTrack() add an
offset argument to shift the position of the requested track
by a certain amount.
* Change: In Cumulus/plugins.block.configuration.GaugeConf, in
createHorizontal(), add a flag to make the source end of the
segment to "stick out". Useful when connecting to a stacked
VIA top, but using a lower layer that can be shifted.
* New: In Cumulus/plugins.block.spares.Spares, BufferPool & QuadTree,
add support for selection and management of multiple buffers at
the same time. Basically returns a list of selected buffer
instances instead of just one instance.
Added HEAVY_LEAF_LOAD flag to Spares. To be used by all tools
classes that makes use of it.
Added QuadTree.runselect(), be sure to call it between different
H-Tree operations, otherwise results will be strange.
* New: In Cumulus/plugins.block.htree.HTree, in case of heavy leaf
load, in the leaf of the tree, allocate three buffers instead
of one. Select them to form a triangle around the main one.
That is, use (i,j), (i+1,j) and (i,j+1).
Added a HTree._connectLeaf() to share the handling of the child
buffer connexions. Whether they are leaf of not and heavy or not.
* Change: Cumulus/plugins.block.Block, expand HTree support to
manage the HEAVY_LEAF_LOAD flag.
* In Cumulus/plugins/block/macro.py, the METAL3 blokage was too narrow
on the left side, allowing use of METAL3 track too close from
internal components.
The METAL5 blockages around jumpers where also too narrow.
Thoses problems where seen with the density filler which put
wires everywhere.
* Change: In Etesian::Slice::fillHole(), instead of cramming the home
with tix_x0 only, put one tie at both ends and fill the rest
with fill_x0. This should help the vendor density filler to
equalze.
* New: In Etesian::Configuration, add the parameter:
"etesian.tieName" (for tix_x0) as it now separate from the simple
filler cells.
* Bug: In cumulus/plugins.chip.libresocio, the ioPadInfos where inverting
"d" and "s" terminals on IOPadInOut. This was indirectly detected by
the DRC complaining about floating gates on the "d" connected nets!
* New: cumulus/plugins.checks, plugin providing a oneDriver() function
to check that each net has one and only one driver. This is for
Cell that are not P&R (in which it is also checked). So, typically
the chip level.
* New: In cumulus/plugins.chip.core2chip, add a call to oneDriver().
* Bug: In cumulus/plugins.chip.core2chip, clear Spice extensions after
save. Otherwise we may use an outdated Spice extension after the
P&R. This is were Net missing Spice::Bit may occur.
The structure of the driver is copied from the Vhdl one. It is not
integrated as a an AllianceFramework one but as a standalone like
GDS. For now use numerical indexes for electrical nodes but also
support strings. The nets are ordereds in reverse alphabetical
order, but a custom order can be defined, if we read the model
from an external SPICE subckt (to be done).
SPICE saving has also been added to the cumulus/rsave plugin
and the block/chip P&R one.
* Change: In cumulus/plugins.chip.chip.doConnectCore(), do not use the
feature of the HTree to connect the root buffer straight to the
corona pin. It prevents the router to insert a diode when those
wires are too long. So let the standard router manage them.
Should add diode insertions in HTree.connectHTrees() later.
* Bug: In cumulus/plugins.chip.powerplane.Builder._connectHTree(),
when building the stacked VIAs over the corona Pin and the
root buffer RoutingPad, pass the GaugeConf.HAccess flag so the
stack stops at METAL4 (top horizontal layer).
Before we where also adding a VIA up to METAL5 which was unused
and caused a minimal area violation.
* Change: In cumulus/plugins.block.macro, the METAL2 blockage was
allowing horizontal tracks to be used but the METAL3 blockage
was conflicting with the end of the perpandiculars.
The router was not able to manage that, so we slightly expand
the METAL2 blockage to encompass the unreachable track.
For the same reason, add a METAL4 blockage over METAL2.
* New: In cumulus/plugins.chip.pads, add METAL5 jumpers on all wires
going to/from the I/O pads on the East & West side. This is a
quick hack as:
1. We should put it also on North/South, but no violation
happens here.
2. We should put it on *ouput* wire only (for only those are
connected to transistors gates).
* New: In cumulus/plugins.chip.macro, put jumpers on the East side
connectors for the SRAM block. Also a quick hack, not robust for
anything else than the SRAM.
* Change: In cumulus/plugins.Block.getLeafUnder(): formerly, we where
using the cut-lines (x/y) to locate which leaf a point is under.
But in case of incomplete tree, it is difficult to manage.
Now we chosse the leaf according to the distance to the center
of the leaf area. Choose the shorter, of course.
This solve the H-Tree DFF bad assignment around the PLL (top
right corner) in LS180.
* Bug: In Cumulus/plugins.block.Block, re-order Etesian tool creation
and virtual net flattening. Must investigate later why it is so
sensitive to at least warn/stop cleanly.
* Bug: In Cumulus/plugins.chip.powerplane.Builder._connectHTree(), is was
previously assumed that a net manged by a H-Tree was always coming from
the outside (i.e. a clock or a reset signal).
It is no longer the case, for example with the PLL internally generated
clock.
So prune internal signals in this method.
The H-Tree support is now allowed for any net, not only the clocks and
not only top-level nets. This allow to better management of the LS180
internal clock signal.
* New: In Cell::flattenNets(Instance*,set<string>,uint64_t) new overload
of the function to allow the user to select nets that will *not*
be flattened. This makes the NoClockFlatten flag effectively obsolete,
we keep it for backward compatibility.
The net names can be of non top level ones. In that case, they must
use the name an HyperNet will get (the Occurrence name). For example:
"instance1.instance2.deep_net_name".
* New: In PyCell, update the wrapper for the new parameter of flattenNets(),
new utility function pyListToStringSet() to translate a Python list into
a C++ set of names.
* New: In EtesianEngine, add support for a list of nets to be excluded
from the flattening procedure. Those excluded nets will also be
excludeds from the Coloquinte nets *and* HFNS synthesis, as they
are likely to be manageds by a H-Tree.
* Change: In AnabaticEngine::_loadGrByNet(), now also skip nets that are
flagged as manually detailed route.
* New: In AnabaticEngine::antennaProtect(), do not try to insert diodes
on nets that are already fixed or detaled route. This replace the
clock exclusion.
* New: In cumulus/plugins.{block,htree,chip}, replace the concept
of clock-tree by the more generic H-Tree. That is, we can ask the P&R
to create H-Tree on any net of the design, not only the ones matcheds
as clock. The net does not even need to be top-level.
This is to manage the PLL internal clock generated by the PLL in
the LS180 chip.
Start to change all reference to "clock" into "H-Tree".
* Bug: In cumulus/plugins.chip.powerplanes.Builder._connectHTree(),
there was an inversion of the H & V routing gauges to compute the
track into which put the H-Tree center to corona edge wiring.
This was causing tracks to be used twice, seen in the ao68000 test
bench.
* Bug: In cumulus/plugins.macro.Macro.__init__(), stick out the rigth number
of pitches on North & East sides (never tested before).
* New: In cumulus/plugins.macro.Macro.__init__(), manage layer change
if the terminal is not in the preferred routing direction. Use BigVia
and put at least two cuts.
* Bug: In cumulus/plugins.chip.Chip.save(), now completely delegate the
saving procedure to the base class (i.e. Block.save() which is
BlockConf.save()).
* Bug/Change: In cumulus/plugins.block.configuration.BlockConf.save(),
Now manage all the configutation, whether it is a simple block or
a whole chip.
In the case of a whole chip we must force the saving on both
chip and corona as the later, being P&R will be seen as a terminal
block and not recursively saved.
* In cumulus/plugins.block.Block.{place,doPnr}(), reorder the
feed insertion and spare buffer deletion call. Formerly, we
were :
1. Creating spare buffersa (Python).
2. Placing (C++)
3. Adding feeds (EtesianEngine::toHurricane() call) (C++).
4. Removing unused spare buffers (Python).
So, step 4 was *not* informing the C++ placement data-structure
created at step 3 of the change. Resulting in occurrences using
deleted Entities (Instance).
Now we swap step 3. and 4. so toHurricane() is called *after*
any Python managed change is done.
Ideally, what we should implement is a way for Python to inform
the C++ data-structure. No real problem here, but time...
* Change: In cumulus/plugins.block.configuration.Configuration.save()
and cumulus/plugins.chip.Chip.save(), according to the kind of
routing gauge we are using (symbolic or real), either recursively
save all the layouts (AP symbolic files) or only the top-level
GDSII (which embed all the hierarchy) one.
* Bug: In cumulus/plugins.chip.pads, we were connecting the ground and
power supplies to all the horizontal wires in the corona ring.
But, when there are more than one and especially at the outer
border of the pad, the vertical connecting wire will create
various shorts over the pad.
Now we connect only to the innermost horizontal wire only.
Had to chech if the core side of the pad is north or south.
* Bug: In cumulus/plugins.chip.powerplane, while building the connexion
from the corona border to the root of the HTree, the horizontal
wire at the top was too close from the border causing a minimal
spacing error in the DRC. Now put two tracks of distance.
* Bug: In cumulus/plugins.block.block.py, always import Python modules
using the exact same path. Otherwise the module may get imported
twice and static variables are duplicated, generating a big mess.
This was causing problem for the LUT in macro.py, and got SRAMs
blocks encapsulated twice.
* New: In cumulus/plugins.block.block.Block.addPlaceHolder(), create
a "place holder" instance over a given area to prevent the placer
from using it. Allow to make space reservation.
* New: In cumulus/plugins.block.configuration.BlockConf, copy the
toXPitch() and toYSlice() methods from spare in order to share
them between modules. Still have to remove some other local copies.
* New: In cumulus/plugins.block.spare.QuadTree, keep a list of all
the X centers of the partitionned areas. For yse by the power lines.
* New: In cumulus/plugins.chip.chip, move doPowerLayout() call from
doChipFloorplan() to doConnectCore(), this is to delay the call
until *after* the spare QuadTree has been created and we can
align the power lines to the centers of the QuadTree.
* New: In cumulus/plugins.chip.pads.Corona.doPowerLayout(), if a
spare QuadTree has been created, align the power lines on the
X center of the leaf areas. This is a cheap way to avoid DRC
errors between the power BigVias and the wires from the various
clock trees (on METAL5).
* New: In cumulus/plugins.block.macro, add an ad-hoc patch for Staf's
SRAMs. The blockage areas are slightly too narrow. We enlarge
them by one pitch.
Jean-Paul Chaput
Luke Kenneth Casson Leighton