From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753480AbcDNDL6 (ORCPT ); Wed, 13 Apr 2016 23:11:58 -0400 Received: from m50-134.163.com ([123.125.50.134]:47208 "EHLO m50-134.163.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751935AbcDNDL4 (ORCPT ); Wed, 13 Apr 2016 23:11:56 -0400 From: zengzhaoxiu@163.com To: linux-kernel@vger.kernel.org Cc: Zhaoxiu Zeng , David Woodhouse , Brian Norris , linux-mtd@lists.infradead.org Subject: [PATCH V3 19/29] mtd: use parity16 in ssfdc Date: Thu, 14 Apr 2016 11:10:51 +0800 Message-Id: <1460603451-5408-1-git-send-email-zengzhaoxiu@163.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1460601525-3822-1-git-send-email-zengzhaoxiu@163.com> References: <1460601525-3822-1-git-send-email-zengzhaoxiu@163.com> X-CM-TRANSID: DtGowABXdzg9Cg9XnGUBAg--.33865S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7ArW8Kr1DXr1rur4rJr1UKFg_yoW8Aw18p3 9xWrW7Jr48W3W7ZFZ7ZF1jq3WFyas7Wa1UGr45G3WFkryrZr17CrnYk3y7Xa42gFyxta1D Zrn8ArWDJan8ArDanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07bj3ktUUUUU= X-Originating-IP: [112.95.225.98] X-CM-SenderInfo: p2hqw6xkdr5xrx6rljoofrz/1tbiNQFLgFSINExVOwAAs1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Zhaoxiu Zeng The original get_parity return even parity of the input number. So hweight of "block_address & 0x7ff" must be odd if block_address is valid. This patch use parity16, and rearrange the code. Signed-off-by: Zhaoxiu Zeng --- drivers/mtd/ssfdc.c | 31 ++++++++----------------------- 1 file changed, 8 insertions(+), 23 deletions(-) diff --git a/drivers/mtd/ssfdc.c b/drivers/mtd/ssfdc.c index daf82ba..1d55f15 100644 --- a/drivers/mtd/ssfdc.c +++ b/drivers/mtd/ssfdc.c @@ -182,24 +182,10 @@ static int read_raw_oob(struct mtd_info *mtd, loff_t offs, uint8_t *buf) return 0; } -/* Parity calculator on a word of n bit size */ -static int get_parity(int number, int size) -{ - int k; - int parity; - - parity = 1; - for (k = 0; k < size; k++) { - parity += (number >> k); - parity &= 1; - } - return parity; -} - /* Read and validate the logical block address field stored in the OOB */ static int get_logical_address(uint8_t *oob_buf) { - int block_address, parity; + int block_address; int offset[2] = {6, 11}; /* offset of the 2 address fields within OOB */ int j; int ok = 0; @@ -215,18 +201,17 @@ static int get_logical_address(uint8_t *oob_buf) /* Check for the signature bits in the address field (MSBits) */ if ((block_address & ~0x7FF) == 0x1000) { - parity = block_address & 0x01; block_address &= 0x7FF; - block_address >>= 1; - if (get_parity(block_address, 10) != parity) { - pr_debug("SSFDC_RO: logical address field%d" - "parity error(0x%04X)\n", j+1, - block_address); - } else { - ok = 1; + ok = parity16(block_address); + if (ok) { + block_address >>= 1; break; } + + pr_debug("SSFDC_RO: logical address field%d" + "parity error(0x%04X)\n", j+1, + block_address); } } -- 2.5.0