.. -*- Mode: rst -*-
.. URLs that changes between the various backends.
.. _Stratus Documentation: file:///usr/share/doc/coriolis2/en/html/stratus/index.html
.. .. |ChipStructure-1| image:: ./images/chip-structure-1.png
.. :alt: Chip Top Structure
.. :align: middle
.. :width: 90%
.. _Python Interface to Coriolis:
|newpage|
Python Interface for |Hurricane| / |Coriolis|
=============================================
The (almost) complete interface of |Hurricane| is exported as a |Python| module
and some part of the other components of |Coriolis| (each one in a separate
module). The interface has been made to mirror as closely as possible the
C++ one, so the C++ doxygen documentation could be used to write code with
either languages.
`Summary of the C++ Documentation <file:../../../index.html>`_
A script could be run directly in text mode from the command line or through
the graphical interface (see `Python Scripts in Cgt`).
Aside for this requirement, the python script can contain anything valid
in |Python|, so don't hesitate to use any package or extention.
Small example of Python/Stratus script:
.. code-block:: python
from Hurricane import *
from Stratus import *
def doSomething ():
# ...
return
def scriptMain ( **kw ):
editor = None
if kw.has_key('editor') and kw['editor']:
editor = kw['editor']
stratus.setEditor( editor )
doSomething()
return
if __name__ == "__main__" :
kw = {}
success = scriptMain( **kw )
shellSuccess = 0
if not success: shellSuccess = 1
sys.exit( shellSuccess )
scriptMain ()
This typical script can be executed in two ways:
#. Run directly as a |Python| script, thanks to the
.. code-block:: python
if __name__ == "__main__" :
part (this is standart |Python|). It is a simple adapter that will
calls :cb:`scriptMain()`.
#. Through |cgt|, either in text or graphical mode. In that case, the
:cb:`scriptMain()` is directly called trough a sub-interpreter.
The arguments of the script are passed through the ``**kw`` dictionnary.
+----------------------+-----------------------------------------------+
| \*\*kw Dictionnary |
+----------------------+-----------------------------------------------+
| Parameter Key/Name | Contents type |
+======================+===============================================+
| ``'cell'`` | A Hurricane cell on which to work. Depending |
| | on the context, it may be ``None``. |
| | For example, when run from |cgt|, it the cell |
| | currently loaded in the viewer, if any. |
+----------------------+-----------------------------------------------+
| ``'editor'`` | The viewer from which the script is run, when |
| | lauched through |cgt|. |
+----------------------+-----------------------------------------------+
Plugins
~~~~~~~
Plugins are |Python| scripts specially crafted to integrate with |cgt|.
Their entry point is a :cb:`scriptMain()` method as described in
`Python Interface to Coriolis`_. They can be called by user scripts
through this method.
Chip Placement
--------------
Automatically perform the placement of a complete chip. This plugin, as well
as the other P&R tools expect a specific top-level hierarchy for the design.
The top-level hierarchy must contains the instances of all the I/O pads and
**exactly one** instance named ``corona`` of an eponym cell ``corona``.
The ``corona`` cell in turn containing the instance of the chip's core model.
The intermediate ``corona`` hierarchical level has been introduced to handle
the possible discoupling between real I/O pads supplied by a foundry and a
symbolic core. So the *chip* level contains only real layout and the corona
and below only symbolic layer.
.. note:: This do not prevent having a design either fully symbolic (pads and core)
or fully real.
.. note:: The ``corona`` also avoid the router to actually have to manage directly
the pads which simplificate it's configuration and accessorily avoid
to have the pads stuffed with blockages.
|bcenter| |ChipStructure-1| |ecenter|
The designer must provide a configuration file that defines the rules for the
placement of the top-level hierarchy (that is, the pads and the core).
This file must be named after the chip's name, by appending ``_ioring.py``
(obviously, it is a |Python| file). For instance if the chip netlist file
is called ``amd2901.vst``, then the configuration file must be named
``amd2901_ioring.vst``.
Example of chip placement configuration file (for ``AM2901``):
.. code-block:: python
from helpers import l, u, n
chip = \
{ 'pads.ioPadGauge' : 'pxlib'
, 'pads.south' : [ 'p_a3' , 'p_a2' , 'p_a1' , 'p_r0'
, 'p_vddick0', 'p_vssick0', 'p_a0' , 'p_i6'
, 'p_i8' , 'p_i7' , 'p_r3' ]
, 'pads.east' : [ 'p_zero' , 'p_i0' , 'p_i1' , 'p_i2'
, 'p_vddeck0', 'p_vsseck0', 'p_q3' , 'p_b0'
, 'p_b1' , 'p_b2' , 'p_b3' ]
, 'pads.north' : [ 'p_noe' , 'p_y3' , 'p_y2' , 'p_y1'
, 'p_y0' , 'p_vddeck1', 'p_vsseck1', 'p_np'
, 'p_ovr' , 'p_cout' , 'p_ng' ]
, 'pads.west' : [ 'p_cin' , 'p_i4' , 'p_i5' , 'p_i3'
, 'p_ck' , 'p_d0' , 'p_d1' , 'p_d2'
, 'p_d3' , 'p_q0' , 'p_f3' ]
, 'core.size' : ( l(1500), l(1500) )
, 'chip.size' : ( l(3000), l(3000) )
, 'chip.clockTree' : True
}
The file must contain *one dictionnary* named ``chip``.
+----------------------+-------------------------------------------------------+
| Chip Dictionnary |
+----------------------+-------------------------------------------------------+
| Parameter Key/Name | Value/Contents type |
+======================+=======================================================+
| ``'pad.ioPadGauge'`` | The routing gauge to use for the pad. Must be given |
| | as it differs from the one used to route standard |
| | inside the core |
+----------------------+-------------------------------------------------------+
| ``'pad.south'`` | Ordered list (left to right) of pad instances names |
| | to put on the south side of the chip |
+----------------------+-------------------------------------------------------+
| ``'pad.east'`` | Ordered list (down to up) of pad instances names |
| | to put on the east side of the chip |
+----------------------+-------------------------------------------------------+
| ``'pad.north'`` | Ordered list (left to right) of pad instances names |
| | to put on the north side of the chip |
+----------------------+-------------------------------------------------------+
| ``'pad.west'`` | Ordered list (down to up) of pad instances names |
| | to put on the west side of the chip |
+----------------------+-------------------------------------------------------+
| ``'core.size'`` | The size of the core (to be used by the placer) |
+----------------------+-------------------------------------------------------+
| ``'chip.size'`` | The size of the whole chip. The sides must be great |
| | enough to accomodate all the pads |
+----------------------+-------------------------------------------------------+
| ``'chip.clockTree'`` | Whether to generate a clock tree or not. This calls |
| | the ClockTree plugin |
+----------------------+-------------------------------------------------------+
Configuration parameters, defaults are defined in ``etc/coriolis2/<STECHNO>/plugins.conf``.
+-----------------------------------+------------------+----------------------------+
| Parameter Identifier | Type | Default |
+===================================+==================+============================+
| **Chip Plugin Parameters** |
+-----------------------------------+------------------+----------------------------+
|``chip.block.rails.count`` | TypeInt | :cb:`5` |
| +------------------+----------------------------+
| | The minimum number of rails around the core |
| | block. Must be odd and suppérior to 5. |
| | One rail for the clock and at least two pairs |
| | of power/grounds |
+-----------------------------------+------------------+----------------------------+
|``chip.block.rails.hWidth`` | TypeInt | :cb:`12` |lambda| |
| +------------------+----------------------------+
| | The horizontal with of the rails |
+-----------------------------------+------------------+----------------------------+
|``chip.block.rails.vWidth`` | TypeInt | :cb:`12` |lambda| |
| +------------------+----------------------------+
| | The vertical with of the rails |
+-----------------------------------+------------------+----------------------------+
|``chip.block.rails.hSpacing`` | TypeInt | :cb:`6` |lambda| |
| +------------------+----------------------------+
| | The spacing, *edge to edge* of two adjacent |
| | horizontal rails |
+-----------------------------------+------------------+----------------------------+
|``chip.block.rails.vSpacing`` | TypeInt | :cb:`6` |lambda| |
| +------------------+----------------------------+
| | The spacing, *edge to edge* of two adjacent |
| | vertical rails |
+-----------------------------------+------------------+----------------------------+
.. note::
If no clock tree is generated, then the clock rail is *not* created.
So even if the requested number of rails ``chip.block.rails.count`` is, say 5,
only four rails (2* ``power``, 2* ``ground``) will be generateds.
Clock Tree
----------
Inserts a clock tree into a block. The clock tree uses the H strategy.
The clock net is splitted into sub-nets, one for each branch of the
tree.
* On **chip** design, the sub-nets are created in the model of the
core block (then trans-hierarchically flattened to be shown at
chip level).
* On **blocks**, the sub nets are created directly in the top block.
* The sub-nets are named according to a simple geometrical scheme.
A common prefix ``ck_htree``, then one postfix by level telling
on which quarter of plane the sub-clock is located:
#. ``_bl``: bottom left plane quarter.
#. ``_br``: bottom right plane quarter.
#. ``_tl``: top left plane quarter.
#. ``_tr``: top right plane quarter.
We can have ``ck_htree_bl``, ``ck_htree_bl_bl``, ``ch_htree_bl_tl`` and so on.
The clock tree plugin works in four steps:
#. Builds the clock tree: creates the top-block abutment box, compute the
required levels of H tree and places the clock buffers.
#. Once the clock buffers are placed, calls the placer (|etesian|) to place
the ordinary standard cells, whithout disturbing clock H-tree buffers.
#. At this point we know the exact positions of all the DFFs, so we can
connect them to the nearest H-tree leaf clock signal.
#. Leaf clock signals that are not connected to any DFFs are removed.
Netlist reorganisation:
* Obviously the top block or chip core model netlist is modified to
contain all the clock sub-nets. The interface is *not* changed.
* If the top block contains instances of other models *and* those models
contain DFFs that get re-connected to the clock sub-nets (from the
top level). Changes both the model netlist and interface to propagate
the relevant clock sub-nets to the instanciated model. The new model
with the added clock signal is renamed with a ``_cts`` suffix.
For example, the sub-block model ``ram.vst`` will become ``ram_cts.vst``.
.. note::
If you are to re-run the clock tree plugin on a netlist, be careful
to erase any previously generated ``_cts`` file (both netlist and
layout: ``rm *_cts.{ap,vst}``). And restart |cgt| to clear its
memory cache.
Configuration parameters, defaults are defined in ``etc/coriolis2/<STECHNO>/plugins.conf``.
+-----------------------------------+------------------+----------------------------+
| Parameter Identifier | Type | Default |
+===================================+==================+============================+
| **ClockTree Plugin Parameters** |
+-----------------------------------+------------------+----------------------------+
|``clockTree.minimumSide`` | TypeInt | :cb:`300` |lambda| |
| +------------------+----------------------------+
| | The minimum size below which the clock tree |
| | will stop to perform quadri-partitions |
+-----------------------------------+------------------+----------------------------+
|``clockTree.buffer`` | TypeString | :cb:`buf_x2` |
| +------------------+----------------------------+
| | The buffer model to use to drive sub-nets |
+-----------------------------------+------------------+----------------------------+
Recursive-Save (RSave)
----------------------
Performs a recursive top down save of all the models from the top cell
loaded in |cgt|. Forces a write of any non-terminal model. This plugin is used
by the clock tree plugin after the netlist clock sub-nets creation.
A Simple Example: AM2901
~~~~~~~~~~~~~~~~~~~~~~~~
To illustrate the capabilities of |Coriolis| tools and |Python| scripting, a small
example, derived from the |Alliance| :cb:`AM2901` is supplied.
This example contains only the synthetized netlists and the :cb:`doChip.py` script
which perform the whole P&R of the design.
You can generate the chip using one of the following method:
#. **Command line mode:** directly run the script:
.. code-block:: sh
dummy@lepka:AM2901> ./doChip -V --cell=amd2901
#. **Graphic mode:** launch |cgt|, load chip netlist ``amd2901`` (the top cell)
then run the |Python| script :cb:`doChip.py`.
.. note::
Between two consecutive run, be sure to erase the netlist/layout generateds:
.. code-block:: sh
dummy@lepka:AM2901> rm *_cts*.vst *.ap