Files
PeakRDL-BusDecoder/src/peakrdl_busdecoder/decoder.py
2025-10-19 21:35:17 -07:00

139 lines
4.4 KiB
Python

from collections import deque
from enum import Enum
from systemrdl.node import AddressableNode
from systemrdl.walker import WalkerAction
from .body import Body, ForLoopBody, IfBody
from .design_state import DesignState
from .listener import BusDecoderListener
from .sv_int import SVInt
from .utils import get_indexed_path
class DecodeLogicFlavor(Enum):
READ = "rd"
WRITE = "wr"
@property
def cpuif_address(self) -> str:
return f"cpuif_{self.value}_addr"
@property
def cpuif_select(self) -> str:
return f"cpuif_{self.value}_sel"
class DecodeLogicGenerator(BusDecoderListener):
def __init__(
self,
ds: DesignState,
flavor: DecodeLogicFlavor,
) -> None:
super().__init__(ds)
self._flavor = flavor
self._decode_stack: deque[Body] = deque() # Tracks decoder body
self._cond_stack: deque[str] = deque() # Tracks conditions nested for loops
# Initial Stack Conditions
self._decode_stack.append(IfBody())
def cpuif_addr_predicate(self, node: AddressableNode) -> list[str]:
# Generate address bounds
addr_width = self._ds.addr_width
l_bound = SVInt(
node.raw_absolute_address,
addr_width,
)
u_bound = l_bound + SVInt(node.total_size, addr_width)
array_stack = list(self._array_stride_stack)
if node.array_dimensions:
array_stack = array_stack[: -len(node.array_dimensions)]
# Handle arrayed components
l_bound_comp = [str(l_bound)]
u_bound_comp = [str(u_bound)]
for i, stride in enumerate(array_stack):
l_bound_comp.append(f"({addr_width}'(i{i})*{SVInt(stride, addr_width)})")
u_bound_comp.append(f"({addr_width}'(i{i})*{SVInt(stride, addr_width)})")
# Generate Conditions
return [
f"{self._flavor.cpuif_address} >= ({'+'.join(l_bound_comp)})",
f"{self._flavor.cpuif_address} < ({'+'.join(u_bound_comp)})",
]
def cpuif_prot_predicate(self, node: AddressableNode) -> list[str]:
if self._flavor == DecodeLogicFlavor.READ:
# Can we have PROT on read? (axi full?)
return []
# TODO: Implement
return []
def enter_AddressableComponent(self, node: AddressableNode) -> WalkerAction | None:
action = super().enter_AddressableComponent(node)
conditions: list[str] = []
conditions.extend(self.cpuif_addr_predicate(node))
conditions.extend(self.cpuif_prot_predicate(node))
condition = " && ".join(f"({c})" for c in conditions)
# Generate condition string and manage stack
if isinstance(self._decode_stack[-1], IfBody) and node.array_dimensions:
# arrayed component with new if-body
self._cond_stack.append(condition)
for i, dim in enumerate(
node.array_dimensions,
):
fb = ForLoopBody(
"int",
f"i{i}",
dim,
)
self._decode_stack.append(fb)
self._decode_stack.append(IfBody())
elif isinstance(self._decode_stack[-1], IfBody):
# non-arrayed component with if-body
with self._decode_stack[-1].cm(condition) as b:
b += f"{self._flavor.cpuif_select}.{get_indexed_path(self._ds.top_node, node)} = 1'b1;"
return action
def exit_AddressableComponent(self, node: AddressableNode) -> None:
if not node.array_dimensions:
return
ifb = self._decode_stack.pop()
if ifb:
self._decode_stack[-1] += ifb
else:
self._decode_stack[-1] += (
f"{self._flavor.cpuif_select}.{get_indexed_path(self._ds.top_node, node)} = 1'b1;"
)
for _ in node.array_dimensions:
b = self._decode_stack.pop()
if not b:
continue
if isinstance(self._decode_stack[-1], IfBody):
with self._decode_stack[-1].cm(self._cond_stack.pop()) as parent_b:
parent_b += b
else:
self._decode_stack[-1] += b
super().exit_AddressableComponent(node)
def __str__(self) -> str:
body = self._decode_stack[-1]
if isinstance(body, IfBody):
with body.cm(...) as b:
b += f"{self._flavor.cpuif_select}.bad_addr = 1'b1;"
return str(body)