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Make swmod respect cpuif byte strobes. #137

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This commit is contained in:
Alex Mykyta
2025-04-10 21:26:08 -07:00
parent bb2fead71a
commit 4aed443c55
3 changed files with 136 additions and 115 deletions
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130
src/peakrdl_regblock/field_logic/__init__.py
View File

@@ -231,49 +231,41 @@ class FieldLogic:
r_modifiable = field.get_property('onread') is not None
buffer_writes = field.parent.get_property('buffer_writes')
buffer_reads = field.parent.get_property('buffer_reads')
accesswidth = field.parent.get_property("accesswidth")
if w_modifiable and not r_modifiable:
# assert swmod only on sw write
if buffer_writes:
# Write strobe arrives from buffer layer instead
wstrb = self.exp.write_buffering.get_write_strobe(field)
return wstrb
else:
# Unbuffered. Use decoder strobe directly
astrb = self.exp.dereferencer.get_access_strobe(field)
return f"{astrb} && decoded_req_is_wr"
if w_modifiable and r_modifiable:
# assert swmod on both sw read and write
astrb = self.exp.dereferencer.get_access_strobe(field)
if buffer_writes or buffer_reads:
conditions = []
if r_modifiable:
if buffer_reads:
rstrb = self.exp.read_buffering.get_trigger(field.parent)
else:
rstrb = f"{astrb} && !decoded_req_is_wr"
conditions.append(rstrb)
if w_modifiable:
if buffer_writes:
wstrb = self.exp.write_buffering.get_write_strobe(field)
else:
wstrb = f"{astrb} && decoded_req_is_wr"
return f"{wstrb} || {rstrb}"
else:
# Unbuffered. Use decoder strobe directly
astrb = self.exp.dereferencer.get_access_strobe(field)
return astrb
# Due to 10.6.1-f, it is impossible for a field that is sw-writable to
# be split across subwords.
# Therefore it is ok to get the subword idx from only one of the bit offsets
# in order to compute the biten range
sidx = field.low // accesswidth
biten = self.get_wr_biten(field, sidx)
wstrb += f" && |({biten})"
if not w_modifiable and r_modifiable:
# assert swmod only on sw read
astrb = self.exp.dereferencer.get_access_strobe(field)
if buffer_reads:
rstrb = self.exp.read_buffering.get_trigger(field.parent)
else:
rstrb = f"{astrb} && !decoded_req_is_wr"
return rstrb
conditions.append(wstrb)
if not conditions:
# Not sw modifiable
return "1'b0"
else:
return " || ".join(conditions)
def get_parity_identifier(self, field: 'FieldNode') -> str:
"""
@@ -305,6 +297,92 @@ class FieldLogic:
return False
def get_wbus_bitslice(self, field: 'FieldNode', subword_idx: int = 0) -> str:
"""
Get the bitslice range string of the internal cpuif's data/biten bus
that corresponds to this field
"""
if field.parent.get_property('buffer_writes'):
# register is buffered.
# write buffer is the full width of the register. no need to deal with subwords
high = field.high
low = field.low
if field.msb < field.lsb:
# slice is for an msb0 field.
# mirror it
regwidth = field.parent.get_property('regwidth')
low = regwidth - 1 - low
high = regwidth - 1 - high
low, high = high, low
else:
# Regular non-buffered register
# For normal fields this ends up passing-through the field's low/high
# values unchanged.
# For fields within a wide register (accesswidth < regwidth), low/high
# may be shifted down and clamped depending on which sub-word is being accessed
accesswidth = field.parent.get_property('accesswidth')
# Shift based on subword
high = field.high - (subword_idx * accesswidth)
low = field.low - (subword_idx * accesswidth)
# clamp to accesswidth
high = max(min(high, accesswidth), 0)
low = max(min(low, accesswidth), 0)
if field.msb < field.lsb:
# slice is for an msb0 field.
# mirror it
bus_width = self.exp.cpuif.data_width
low = bus_width - 1 - low
high = bus_width - 1 - high
low, high = high, low
return f"[{high}:{low}]"
def get_wr_biten(self, field: 'FieldNode', subword_idx: int=0) -> str:
"""
Get the bit-enable slice that corresponds to this field
"""
if field.parent.get_property('buffer_writes'):
# Is buffered. Use value from write buffer
# No need to check msb0 ordering. Bus is pre-swapped, and bitslice
# accounts for it
bslice = self.get_wbus_bitslice(field)
wbuf_prefix = self.exp.write_buffering.get_wbuf_prefix(field)
return wbuf_prefix + ".biten" + bslice
else:
# Regular non-buffered register
bslice = self.get_wbus_bitslice(field, subword_idx)
if field.msb < field.lsb:
# Field gets bitswapped since it is in [low:high] orientation
value = "decoded_wr_biten_bswap" + bslice
else:
value = "decoded_wr_biten" + bslice
return value
def get_wr_data(self, field: 'FieldNode', subword_idx: int=0) -> str:
"""
Get the write data slice that corresponds to this field
"""
if field.parent.get_property('buffer_writes'):
# Is buffered. Use value from write buffer
# No need to check msb0 ordering. Bus is pre-swapped, and bitslice
# accounts for it
bslice = self.get_wbus_bitslice(field)
wbuf_prefix = self.exp.write_buffering.get_wbuf_prefix(field)
return wbuf_prefix + ".data" + bslice
else:
# Regular non-buffered register
bslice = self.get_wbus_bitslice(field, subword_idx)
if field.msb < field.lsb:
# Field gets bitswapped since it is in [low:high] orientation
value = "decoded_wr_data_bswap" + bslice
else:
value = "decoded_wr_data" + bslice
return value
#---------------------------------------------------------------------------
# Field Logic Conditionals

82
src/peakrdl_regblock/field_logic/sw_onwrite.py
View File

@@ -36,84 +36,6 @@ class _OnWrite(NextStateConditional):
return f"{strb} && decoded_req_is_wr"
def _wbus_bitslice(self, field: 'FieldNode', subword_idx: int = 0) -> str:
# Get the source bitslice range from the internal cpuif's data bus
if field.parent.get_property('buffer_writes'):
# register is buffered.
# write buffer is the full width of the register. no need to deal with subwords
high = field.high
low = field.low
if field.msb < field.lsb:
# slice is for an msb0 field.
# mirror it
regwidth = field.parent.get_property('regwidth')
low = regwidth - 1 - low
high = regwidth - 1 - high
low, high = high, low
else:
# Regular non-buffered register
# For normal fields this ends up passing-through the field's low/high
# values unchanged.
# For fields within a wide register (accesswidth < regwidth), low/high
# may be shifted down and clamped depending on which sub-word is being accessed
accesswidth = field.parent.get_property('accesswidth')
# Shift based on subword
high = field.high - (subword_idx * accesswidth)
low = field.low - (subword_idx * accesswidth)
# clamp to accesswidth
high = max(min(high, accesswidth), 0)
low = max(min(low, accesswidth), 0)
if field.msb < field.lsb:
# slice is for an msb0 field.
# mirror it
bus_width = self.exp.cpuif.data_width
low = bus_width - 1 - low
high = bus_width - 1 - high
low, high = high, low
return f"[{high}:{low}]"
def _wr_data(self, field: 'FieldNode', subword_idx: int=0) -> str:
if field.parent.get_property('buffer_writes'):
# Is buffered. Use value from write buffer
# No need to check msb0 ordering. Bus is pre-swapped, and bitslice
# accounts for it
bslice = self._wbus_bitslice(field)
wbuf_prefix = self.exp.write_buffering.get_wbuf_prefix(field)
return wbuf_prefix + ".data" + bslice
else:
# Regular non-buffered register
bslice = self._wbus_bitslice(field, subword_idx)
if field.msb < field.lsb:
# Field gets bitswapped since it is in [low:high] orientation
value = "decoded_wr_data_bswap" + bslice
else:
value = "decoded_wr_data" + bslice
return value
def _wr_biten(self, field: 'FieldNode', subword_idx: int=0) -> str:
if field.parent.get_property('buffer_writes'):
# Is buffered. Use value from write buffer
# No need to check msb0 ordering. Bus is pre-swapped, and bitslice
# accounts for it
bslice = self._wbus_bitslice(field)
wbuf_prefix = self.exp.write_buffering.get_wbuf_prefix(field)
return wbuf_prefix + ".biten" + bslice
else:
# Regular non-buffered register
bslice = self._wbus_bitslice(field, subword_idx)
if field.msb < field.lsb:
# Field gets bitswapped since it is in [low:high] orientation
value = "decoded_wr_biten_bswap" + bslice
else:
value = "decoded_wr_biten" + bslice
return value
def get_assignments(self, field: 'FieldNode') -> List[str]:
accesswidth = field.parent.get_property("accesswidth")
@@ -124,8 +46,8 @@ class _OnWrite(NextStateConditional):
# field does not get split between subwords
R = self.exp.field_logic.get_storage_identifier(field)
D = self._wr_data(field, sidx)
S = self._wr_biten(field, sidx)
D = self.exp.field_logic.get_wr_data(field, sidx)
S = self.exp.field_logic.get_wr_biten(field, sidx)
lines = [
f"next_c = {self.get_onwrite_rhs(R, D, S)};",
"load_next_c = '1;",

21
tests/test_swacc_swmod/tb_template.sv
View File

@@ -88,6 +88,27 @@
disable fork;
assert(fired);
// Verify that swmod does NOT trigger if strobes not set
fired = 0;
fork
begin
##0;
forever begin
assert(cb.hwif_out.r2.f.value == 21);
if(cb.hwif_out.r2.f.swmod) break;
@cb;
end
fired = 1;
end
begin
cpuif.write('h1, 22, 0);
repeat(4) @cb;
end
join_any
disable fork;
assert(!fired);
// Verify that hwif changes 1 cycle after swmod
fired = 0;
fork