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soc/cores/ecc: cosmetic cleanups.

This commit is contained in:
Florent Kermarrec 2021-02-18 10:00:27 +01:00
parent 7ce5aef428
commit 12bdf43958
1 changed files with 21 additions and 24 deletions
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27
litex/soc/cores/ecc.py
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@ -1,7 +1,7 @@
#
# This file is part of LiteX.
#
# Copyright (c) 2018-2019 Florent Kermarrec <florent@enjoy-digital.fr>
# Copyright (c) 2018-2021 Florent Kermarrec <florent@enjoy-digital.fr>
# SPDX-License-Identifier: BSD-2-Clause
"""
@ -26,7 +26,6 @@ def compute_m_n(k):
n = m + k
return m, n
def compute_syndrome_positions(m):
r = []
i = 1
@ -35,7 +34,6 @@ def compute_syndrome_positions(m):
i = i << 1
return r
def compute_data_positions(m):
r = []
e = compute_syndrome_positions(m)
@ -44,7 +42,6 @@ def compute_data_positions(m):
r.append(i)
return r
def compute_cover_positions(m, p):
r = []
i = p
@ -54,7 +51,7 @@ def compute_cover_positions(m, p):
i += 2*p
return r
# SECDED (Single Error Detection, Double Error Detection) ------------------------------------------
# SECDED (Single Error Correction, Double Error Detection) -----------------------------------------
class SECDED:
def place_data(self, data, codeword):
@ -104,15 +101,15 @@ class ECCEncoder(SECDED, Module):
codeword_d_p = Signal(n)
codeword = Signal(n + 1)
# place data bits in codeword
# Place data bits in codeword.
self.place_data(i, codeword_d)
# compute and place syndrome bits
# Compute and place syndrome bits.
self.compute_syndrome(codeword_d, syndrome)
self.comb += codeword_d_p.eq(codeword_d)
self.place_syndrome(syndrome, codeword_d_p)
# compute parity
# Compute parity.
self.compute_parity(codeword_d_p, parity)
# output codeword + parity
# Output codeword + parity.
self.comb += o.eq(Cat(parity, codeword_d_p))
# ECC Decoder --------------------------------------------------------------------------------------
@ -135,26 +132,26 @@ class ECCDecoder(SECDED, Module):
codeword = Signal(n)
codeword_c = Signal(n)
# input codeword + parity
# Input codeword + parity.
self.compute_parity(i, parity)
self.comb += codeword.eq(i[1:])
# compute_syndrome
# Compute_syndrome
self.compute_syndrome(codeword, syndrome)
self.comb += If(~self.enable, syndrome.eq(0))
# locate/correct codeword error bit if any and flip it
# Locate/correct codeword error bit if any and flip it.
cases = {}
cases["default"] = codeword_c.eq(codeword)
for i in range(1, 2**len(syndrome)):
cases[i] = codeword_c.eq(codeword ^ (1<<(i-1)))
self.comb += Case(syndrome, cases)
# extract data / status
# Extract data / status.
self.extract_data(codeword_c, o)
self.comb += [
If(syndrome != 0,
# double error detected
# Double error detected.
If(~parity,
ded.eq(1)
# single error corrected
# Single error corrected.
).Else(
sec.eq(1)
)