On Mon, Mar 23, 2020 at 05:03:02AM +0000, Ajay.Kathat@xxxxxxxxxxxxx wrote: > On 22/03/20 5:34 pm, George Spelvin wrote: >> The code in lib/ is the desired polynomial, and even includes >> the 1-bit left shift in the table rather than needing to code >> it explicitly. > > These changes will break functionality. The crc7 used in 'wilc' is based > on the previous revision(commit# ad241528c491). The new changes can not > be adopted from 'wilc' device side because the crc calculation is done > on hardware IP and it expects the value based the older implementation. I'm confused. Both crc7 functions compute the exact same value. I put them in a test harness and checked that they produce identical output before submitting. The only difference is that the implementation I deleted does crc = 0x7f; while (len--) crc = crc_cyndrome_table[(crc << 1) ^ *byte++]; return crc << 1; while the lib/crc7.c code maintains its "crc" state value already shifted left 1 bit, so it can use the simpler loop: crc = 0xfe; /* 0x7f << 1 */ while (len--) crc = crc_cyndrome_table2[crc ^ *byte++]; return crc; It's not a different CRC-7, it's the *exact same* CRC-7. You can see that the syndrome tables are identical, just shifted one bit over. > It seems you are using an old version of 'wilc' driver. This logic is > already changed in the latest code. We have remove custom behavior to > decide p2p role (P2P_Go/P2P_Client) between 2 wilc devices based on > 'local_random' value and now relies on 'intent' value received from 'wpa_s'. > To submit changes for wilc, please use 'staging-next' branch of > https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git repo. Ah, thanks. Sorry for the noise, then. The rcr7 patch still applies, however.
