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/* IBM_PROLOG_BEGIN_TAG */
/* This is an automatically generated prolog. */
/* */
/* $Source: src/occ/firdata/ecc.C $ */
/* */
/* OpenPOWER OnChipController Project */
/* */
/* Contributors Listed Below - COPYRIGHT 2015 */
/* [+] International Business Machines Corp. */
/* */
/* */
/* Licensed under the Apache License, Version 2.0 (the "License"); */
/* you may not use this file except in compliance with the License. */
/* You may obtain a copy of the License at */
/* */
/* http://www.apache.org/licenses/LICENSE-2.0 */
/* */
/* Unless required by applicable law or agreed to in writing, software */
/* distributed under the License is distributed on an "AS IS" BASIS, */
/* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or */
/* implied. See the License for the specific language governing */
/* permissions and limitations under the License. */
/* */
/* IBM_PROLOG_END_TAG */
#include <native.h>
#include <ecc.h>
/** Matrix used for ECC calculation.
*
* Each row of this is the set of data word bits that are used for
* the calculation of the corresponding ECC bit. The parity of the
* bitset is the value of the ECC bit.
*
* ie. ECC[n] = eccMatrix[n] & data
*
* Note: To make the math easier (and less shifts in resulting code),
* row0 = ECC7. HW numbering is MSB, order here is LSB.
*
* These values come from the HW design of the ECC algorithm.
*/
static uint64_t eccMatrix[] = {
/*0000000000000000111010000100001000111100000011111001100111111111 */
0x0000e8423c0f99ff,
/*0000000011101000010000100011110000001111100110011111111100000000 */
0x00e8423c0f99ff00,
/*1110100001000010001111000000111110011001111111110000000000000000 */
0xe8423c0f99ff0000,
/*0100001000111100000011111001100111111111000000000000000011101000 */
0x423c0f99ff0000e8,
/*0011110000001111100110011111111100000000000000001110100001000010 */
0x3c0f99ff0000e842,
/*0000111110011001111111110000000000000000111010000100001000111100 */
0x0f99ff0000e8423c,
/*1001100111111111000000000000000011101000010000100011110000001111 */
0x99ff0000e8423c0f,
/*1111111100000000000000001110100001000010001111000000111110011001 */
0xff0000e8423c0f99
};
/** Syndrome calculation matrix.
*
* Maps syndrome to flipped bit.
*
* To perform ECC correction, this matrix is a look-up of the bit
* that is bad based on the binary difference of the good and bad
* ECC. This difference is called the "syndrome".
*
* When a particular bit is on in the data, it cause a column from
* eccMatrix being XOR'd into the ECC field. This column is the
* "effect" of each bit. If a bit is flipped in the data then its
* "effect" is missing from the ECC. You can calculate ECC on unknown
* quality data and compare the ECC field between the calculated
* value and the stored value. If the difference is zero, then the
* data is clean. If the difference is non-zero, you look up the
* difference in the syndrome table to identify the "effect" that
* is missing, which is the bit that is flipped.
*
* Notice that ECC bit flips are recorded by a single "effect"
* bit (ie. 0x1, 0x2, 0x4, 0x8 ...) and double bit flips are identified
* by the UE status in the table.
*
* Bits are in MSB order.
*/
static uint8_t syndromeMatrix[] = {
ECC_GD, ECC_E7, ECC_E6, ECC_UE, ECC_E5, ECC_UE, ECC_UE, 47,
ECC_E4, ECC_UE, ECC_UE, 37, ECC_UE, 35, 39, ECC_UE,
ECC_E3, ECC_UE, ECC_UE, 48, ECC_UE, 30, 29, ECC_UE,
ECC_UE, 57, 27, ECC_UE, 31, ECC_UE, ECC_UE, ECC_UE,
ECC_E2, ECC_UE, ECC_UE, 17, ECC_UE, 18, 40, ECC_UE,
ECC_UE, 58, 22, ECC_UE, 21, ECC_UE, ECC_UE, ECC_UE,
ECC_UE, 16, 49, ECC_UE, 19, ECC_UE, ECC_UE, ECC_UE,
23, ECC_UE, ECC_UE, ECC_UE, ECC_UE, 20, ECC_UE, ECC_UE,
ECC_E1, ECC_UE, ECC_UE, 51, ECC_UE, 46, 9, ECC_UE,
ECC_UE, 34, 10, ECC_UE, 32, ECC_UE, ECC_UE, 36,
ECC_UE, 62, 50, ECC_UE, 14, ECC_UE, ECC_UE, ECC_UE,
13, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE,
ECC_UE, 61, 8, ECC_UE, 41, ECC_UE, ECC_UE, ECC_UE,
11, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE,
15, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE,
ECC_UE, ECC_UE, 12, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE,
ECC_E0, ECC_UE, ECC_UE, 55, ECC_UE, 45, 43, ECC_UE,
ECC_UE, 56, 38, ECC_UE, 1, ECC_UE, ECC_UE, ECC_UE,
ECC_UE, 25, 26, ECC_UE, 2, ECC_UE, ECC_UE, ECC_UE,
24, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE, 28, ECC_UE,
ECC_UE, 59, 54, ECC_UE, 42, ECC_UE, ECC_UE, 44,
6, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE,
5, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE,
ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE,
ECC_UE, 63, 53, ECC_UE, 0, ECC_UE, ECC_UE, ECC_UE,
33, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE,
3, ECC_UE, ECC_UE, 52, ECC_UE, ECC_UE, ECC_UE, ECC_UE,
ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE,
7, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE,
ECC_UE, 60, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE,
ECC_UE, ECC_UE, ECC_UE, ECC_UE, 4, ECC_UE, ECC_UE, ECC_UE,
ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE, ECC_UE,
};
/** Returns the parity of x, i.e. the number of 1-bits in x modulo 2.
* Replacement for __builtin_parityl
*/
uint8_t parity_check( uint64_t i_data )
{
int ones = 0;
uint32_t x;
for( x=0; x<(sizeof(i_data)*8); x++ )
{
if( i_data & (0x8000000000000000ull >> x) )
{
ones++;
}
}
return ones%2;
}
/** Create the ECC field corresponding to a 8-byte data field
*
* @param[in] i_data - The 8 byte data to generate ECC for.
* @return The 1 byte ECC corresponding to the data.
*/
uint8_t generateECC(uint64_t i_data)
{
uint8_t result = 0;
int i = 0;
for (i = 0; i < 8; i++)
{
result |= (parity_check(eccMatrix[i] & i_data) << i);
}
return result;
}
/** Verify the data and ECC match or indicate how they are wrong.
*
* @param[in] i_data - The data to check ECC on.
* @param[in] i_ecc - The [supposed] ECC for the data.
*
* @return eccBitfield or 0-64.
*
* @retval GD - Indicates the data is good (matches ECC).
* @retval UE - Indicates the data is uncorrectable.
* @retval all others - Indication of which bit is incorrect.
*/
uint8_t verifyECC(uint64_t i_data, uint8_t i_ecc)
{
return syndromeMatrix[generateECC(i_data) ^ i_ecc];
}
/** Correct the data and/or ECC.
*
* @param[in,out] io_data - Data to check / correct.
* @param[in,out] io_ecc - ECC to check / correct.
*
* @return eccBitfield or 0-64.
*
* @retval GD - Data is good.
* @retval UE - Data is uncorrectable.
* @retval all others - which bit was corrected.
*/
uint8_t correctECC(uint64_t* io_data, uint8_t* io_ecc)
{
uint8_t badBit = verifyECC(*io_data, *io_ecc);
if ((badBit != ECC_GD) && (badBit != ECC_UE)) /* Good is done, UE is hopeless. */
{
/* Determine if the ECC or data part is bad, do bit flip. */
if (badBit >= ECC_E7)
{
*io_ecc ^= (1 << (badBit - ECC_E7));
}
else
{
*io_data ^= (1ul << (63 - badBit));
}
}
return badBit;
}
void injectECC(const uint8_t* i_src,
uint32_t i_srcSz,
uint8_t* o_dst)
{
if (0 != (i_srcSz % sizeof(uint64_t)))
{
return;
}
uint32_t i = 0;
uint32_t o = 0;
for(i = 0, o = 0;
i < i_srcSz;
i += sizeof(uint64_t), o += sizeof(uint64_t) + sizeof(uint8_t))
{
/* Read data word, copy to destination. */
uint64_t data = *((const uint64_t*)(&i_src[i]));
*((uint64_t*)(&o_dst[o])) = data;
data = be64toh(data);
/* Calculate ECC, copy to destination. */
uint8_t ecc = generateECC(data);
o_dst[o + sizeof(uint64_t)] = ecc;
}
}
eccStatus removeECC(uint8_t* io_src,
uint8_t* o_dst, uint32_t i_dstSz)
{
if (0 != (i_dstSz % sizeof(uint64_t)))
{
return -1;
}
eccStatus rc = ECC_CLEAN;
uint32_t i = 0, o = 0;
for(i = 0, o = 0;
o < i_dstSz;
i += sizeof(uint64_t) + sizeof(uint8_t), o += sizeof(uint64_t))
{
/* Read data and ECC parts. */
uint64_t data = *((uint64_t*)(&io_src[i]));
data = be64toh(data);
uint8_t ecc = io_src[i + sizeof(uint64_t)];
/* Calculate failing bit and fix data. */
uint8_t badBit = correctECC(&data, &ecc);
/* Return data to big endian. */
data = htobe64(data);
/* Perform correction and status update. */
if (badBit == ECC_UE)
{
rc = ECC_UNCORRECTABLE;
}
else if (badBit != ECC_GD)
{
if (rc != ECC_UNCORRECTABLE)
{
rc = ECC_CORRECTED;
}
*((uint64_t*)(&io_src[i])) = data;
io_src[i + sizeof(uint64_t)] = ecc;
}
/* Copy fixed data to destination buffer. */
*((uint64_t*)(&o_dst[o])) = data;
}
return rc;
}
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