From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756715AbaEAKDq (ORCPT ); Thu, 1 May 2014 06:03:46 -0400 Received: from mail-wi0-f170.google.com ([209.85.212.170]:43416 "EHLO mail-wi0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755768AbaEAJ6H (ORCPT ); Thu, 1 May 2014 05:58:07 -0400 From: Lee Jones To: linux-kernel@vger.kernel.org Cc: computersforpeace@gmail.com, linux-mtd@lists.infradead.org, kernel@stlinux.com, Lee Jones Subject: [PATCH 28/47] mtd: nand: stm_nand_bch: bad block marking helpers Date: Thu, 1 May 2014 10:56:35 +0100 Message-Id: <1398938214-17847-29-git-send-email-lee.jones@linaro.org> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1398938214-17847-1-git-send-email-lee.jones@linaro.org> References: <1398938214-17847-1-git-send-email-lee.jones@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Bad Block Markers (BBMs) keep track of unusable/unsuitable memory blocks which can prevent unnecessary data loss. These helpers aid in reading and writing to/from the Bad Block Tables (BBTs) where the BBMs are stored. Signed-off-by: Lee Jones --- drivers/mtd/nand/stm_nand_bch.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/drivers/mtd/nand/stm_nand_bch.c b/drivers/mtd/nand/stm_nand_bch.c index 83faffe..27a87a3 100644 --- a/drivers/mtd/nand/stm_nand_bch.c +++ b/drivers/mtd/nand/stm_nand_bch.c @@ -712,6 +712,35 @@ static int bch_write(struct mtd_info *mtd, struct nand_chip *chip, return 0; } +/* + * Bad Block Tables/Bad Block Markers + */ +#define BBT_MARK_BAD_FACTORY 0x0 +#define BBT_MARK_BAD_WEAR 0x1 +#define BBT_MARK_GOOD 0x3 + +static void bbt_set_block_mark(uint8_t *bbt, uint32_t block, uint8_t mark) +{ + unsigned int byte = block >> 2; + unsigned int shift = (block & 0x3) << 1; + + bbt[byte] &= ~(0x3 << shift); + bbt[byte] |= ((mark & 0x3) << shift); +} + +static uint8_t bbt_get_block_mark(uint8_t *bbt, uint32_t block) +{ + unsigned int byte = block >> 2; + unsigned int shift = (block & 0x3) << 1; + + return (bbt[byte] >> shift) & 0x3; +} + +static int bbt_is_block_bad(uint8_t *bbt, uint32_t block) +{ + return bbt_get_block_mark(bbt, block) == BBT_MARK_GOOD ? 0 : 1; +} + /* Scan block for IBBT signature */ static int bch_find_ibbt_sig(struct nandi_controller *nandi, uint32_t block, int *bak, uint8_t *vers, -- 1.8.3.2