W dniu 15 czerwca 2011 14:09 uÅytkownik Arend van Spriel
<arend@xxxxxxxxxxxx> napisaÅ:
> On 06/15/2011 01:53 PM, RafaÅ MiÅecki wrote:
>>
>> Âstatic u8 bcma_sprom_crc(const u16 *sprom)
>> Â{
>> - Â Â Â int word;
>> - Â Â Â u8 crc = 0xFF;
>> + Â Â Â u8 crc;
>> + Â Â Â u8 sprom2[SSB_SPROMSIZE_WORDS_R4 * 2 - 1];
>> + Â Â Â u8 table[CRC8_TABLE_SIZE];
>> + Â Â Â u16 word;
>>
>> + Â Â Â /* u16 to u8 */
>> Â Â Â Âfor (word = 0; word< ÂSSB_SPROMSIZE_WORDS_R4 - 1; word++) {
>> - Â Â Â Â Â Â Â crc = bcma_crc8(crc, sprom[word]& Â0x00FF);
>> - Â Â Â Â Â Â Â crc = bcma_crc8(crc, (sprom[word]& Â0xFF00)>> Â8);
>> + Â Â Â Â Â Â Â sprom2[word * 2] = sprom[word]& Â0x00FF;
>> + Â Â Â Â Â Â Â sprom2[(word * 2) + 1] = (sprom[word]& Â0xFF00)>> Â8;
>> Â Â Â Â}
>> - Â Â Â crc = bcma_crc8(crc, sprom[SSB_SPROMSIZE_WORDS_R4 - 1]& Â0x00FF);
>> + Â Â Â /* 127th byte */
>> + Â Â Â sprom2[(SSB_SPROMSIZE_WORDS_R4 * 2) - 2] =
>> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â sprom[SSB_SPROMSIZE_WORDS_R4 - 1]&
>> Â0x00FF;
>> +
>> + Â Â Â /* Prepare table, 0xAB is x^8 + x^7 + x^6 + x^4 + x^2 + 1 */
>> + Â Â Â crc8_populate_lsb(table, 0xAB);
>> +
>> + Â Â Â /* Calculate */
>> + Â Â Â crc = crc8(table, sprom2, (SSB_SPROMSIZE_WORDS_R4 * 2) - 1, 0xFF);
>> Â Â Â Âcrc ^= 0xFF;
>>
>> Â Â Â Âreturn crc;
>
> You could do (I think):
>
> crc8_populate_lsb(table, 0xAB);
> for (word = 0; word< ÂSSB_SPROMSIZE_WORDS_R4; word++) {
> Â Â Â Âu16 val = cpu_to_le16(sprom[word]);
> Â Â Â Âcrc = crc8(table,&val, sizeof(u16), crc);
> }
Maybe not a perfect/optimal solution (crc8 focuses on tables, we do
double loop instead) but should work. Thanks for the tip.
--
RafaÅ
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