* Change: In EtesianEngine::_postCreate(), issue a warning if the list of
feeds is empy (configuration: "cfg.etesian.feedNames").
* New: Add a FeedCeels::getFeedByWidth() method to get feeds by their
width in DbU::Unit and not only pitches.
* Change: In Placement::Slice::fillHole(), invert the tie filling and
feeds filling stage. Now we first try to fill the row hole with
feeds, using the widest first, and if they are not configured or
too wide, use the tie.
As the tie *should* also be integrated in the feed list, we may
suppress altogether the fallback tie filling step. Keep it for now.
* Change: In Placement::slice::createDiodeUnder(), the inserted diode
*may* be smaller than the feed it replace. So, in this case, add
a complementary feed to fill the gap.
NOTE 1: Out of lazyness, we add only *one* complementary filler
cell. So there *must* be one of a width wich correspond
exactly to the difference between the original feed and
the diode. Otherwise, gap will remains.
NOTE 2: With wider feed cells, they may cross the GCell border.
But we must insert the diode under the GCell, otherwise
the global routing will be defective. So, for now, reject
feeds that cross the boundary. Must be done more smartly
by inserting the diode over the left or right side of
the feed.
* Change: In Etesianengine::toHurricane(), no longer call interTies().
This *should* no longer be needed as almost all standard cells
(SxLib & FlexLib) already contains polarisation contacts.
So do not need to disturb the placement.
Secondly, in presence of a H-Tree, when there is not enough
space to insert a sufficient number of tie cell, the lefmost one
in the sub-row is shifted to left, overlaping the H-Tree buffer
cells. This is a bug (even signaled by a warning). But as this
part is disabled, I won't correct it soon...
* 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.
* In Etesian::Slice::createDiodeUnder(), delete the Instance *after*
removing the tile referring it. This was working, unless we
active the debug mode which tries to print the Tile's instance.
* In EtesianEngine::place(), no longer call toHurricane() at the
end of the placement. Must now be done as a separate step.
Exported to Python interface.
This fix is related to the spare buffer removal memory
corruption
First part of the antenna effect protection : diode insertions.
Anabatic::antennaProtect(Net*) and it's supporting infrastructure
has been rewritten & simplificated. Must be used in conjuction
with the "Flexlib" bloat model of Etesian. A cursory description
of the algorithm has been added in the source file.
* New: GCell::hasNet() to tell if net is going through a GCell,
either as a straigth wire or has a local GContact (turn,
branch, terminal).
* New: Etesian::BloatFlexib class (tagged "Flexlib") suited for
flexlib uses. It is derived from "nsxlib".
To have enough space to insert all the wanted diodes, we
enlarge "mx2_x2" & "mx3_x2" of resp. 1 and 2 pitches.
This is an empiric finding, Yosys seems very fond of thoses
gates and we often see them underneath area where no space
was available to put a diode... May need some more fine grained
analysis.
* Bug: In Etesian::Placement::Slice::fillHole(), do not use the xmin
previous bound, but pitch it (by excess). Insert ties *only* if
they completely fit in the free space.
This bug was showing *between* two SRAMs side-by-side, a column
of tie was inserted...
* Bug: In EtesianEngine::toHurricane(), when looping over the AB of all the
FIXED instances occurrences, we where excluding contained AB instead of
merging them...
* New: In EtesianEngine, add a "placedArea" attribute to restrict the
placement area to a part only of the whole abutement box. This a
way to exclude some area containing *big* hard block.
The placer terribly slow down when tring to "push aside" cells
from the area taken by the block.
This will be also used to restrict the clock tree covered area.
It is far from optimal but will do for now.
NOTE: The placeArea must be expressed in the coordinate system of
the sub-block to be placed, if one has been defined.
* Change: In EtesianEngine::globalPlace(), disable the call to
antennaProtect(). First reason is that, after all, Coloquinte
do not handle so well the resizing of the cells "on the fly",
it overspill the boundaries sometimes. Second reason is that
as we cannot know the routing tree at this stage, we will not
be able to choose the correct points for diode insertions.
We only have a Steiner tree wich may not be the same as a
density driven Dijkstra.
* Change: In Etesian::Area, the Occurrence to the Instances where
not stored in a uniform way. Some where starting from the
placed sub-block, some where starting from the top level
(corona), making their processing (and remembering it) tricky.
Now, they are all expressed from the top cell (corona).
The coordinate system is now systematically the one of the
top block (*not* the block).
Create various overloaded functions EtesianEngine::toCell()
and EtesianEngine::toBlock() to ease Occurrence & coordinate
translations.
* New: In Etesian::Slice::createDiodeUnder(), add a X position hint.
Search is done by going through the whole slice range and
minimizing the distance to the hint. If it starts to be too
slow, we may optimize.
* Bug: In EtesianEngine::toColoquinte(), the placement of the top
level external pins was not taken into account (this at last
explain their weird positioning).
* New: AnabaticEngine::antennaProtect(), new algorithm to avoid
antenna effect. This step must be done *after* global routing
and *before* detailed routing. This way we have access to the
real routing and can mend it (along with the netlist) to
insert diodes at the rigth points.
From the global routing we build clusters (DiodeCluster) of
RoutingPads connected through a set of wire whose total length
is below the antenna effect threshold. Long wires connecting the
clusters are also tagged because we need to put a diode between
them and the first RoutingPad of the cluster. This is to avoid
a long METAL2 wire connecting to the RoutingPad before the diode is
connected through METAL3 (in case of misalignment).
This protection is not even enough. For *very long* wires, we
needs to put *more* than one diode (this is to be implemented).
* New: In Etesian::Configuration add new parameters for antenna
effect management:
* "etesian.diodeName" : the name of the diode cell.
* "etesian.antennaMaxwl" : maximum length above which antenna
effect can occur. Must be the maximum for all the normal
routing layers.
* "etesian.antennaInsertThreshold" : during the placement steps,
threshold for linear disruption at which we will look for
the RSMT and insert diodes.
* New: In EtesianEngine::antennaProtect(), at a designated point
in the placement iteratives step, when the spreading starts to
be significant enough estimate the RSMT length and add a diode
if need be. The diode will be put side by side with the driver
cell. This is done by enlarging the driver cell of the diode
width.
* New: In EtesianEngine::_updatePlacement(), in the final stage,
modify the netlist to connect the diode. The diode will be
put on the side of the cell closest to the driver. This may
alow to make the connexion directly in METAL1 in the future.
* Change: In etesian/Placement.cpp, make the whole placement
structure a persistent attribute of the EtesianEngine so
it can be used afterwards.
Add a post-placement diode insertion feature. Finally
unused as they are added on the fly during placement.
In the Area, add data about the diode tie in the TieLut.
* Change: Add EtesianEnginea::clearColoquinte(), to keep the
post-placement structure while purging the Coloquinte one.
* Change: In cumulus/plugins.block.block, keep the Etesian engine
until the whole P&R is done, so we potentially can exploit
the post-placement datas.
* Bug: In cumulus/plugins.chip.power.GoCb(), for the METAL1 power
and ground wires coming from the standard cell, it was assumed
they where made of Horizontal segments, this is not the case
in FlexLib... So force to consider the plane as Horizontal when
we are processing that plane.
Better solution should be to use Horizontals...
* New: In Etesian/Placement::Area, added support to take into account
bulk inside cells. Currently only hard-wired configuration for
FlexLib is available. Should add a front-end to analyse the
cells of the library to lookup for bulk ties in the future.
* New: In Etesian::Configuration, added "etesian.lacthUpDistance" to
control tie cells insertion (for polarization contacts).
* New: Etesian/Placement as a complete replacement for FeedCells.
Rebuild the complete slicing structure of the placement to
serve as a building block for post-placement changes under
Coriolis. Currently used to regularly insert body ties.
This is not optimal as we displace cells in each slice in
a non-coordinated manner.
* New: In cumulus/plugins/block.configuration.FeedsConf, register
the "etesian.latchUpDistance" parameter. Provides the tie width.
* New: In cumulus/plugins.block.spares, add ties around the buffer
pool block and "cap ties" at both end of each slice.
Jean-Paul Chaput