From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from conuserg-09.nifty.com ([210.131.2.76]) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1dwgjR-0000Vc-71 for linux-mtd@lists.infradead.org; Tue, 26 Sep 2017 03:40:27 +0000 From: Masahiro Yamada To: linux-mtd@lists.infradead.org Cc: Masahiro Yamada , Cyrille Pitchen , linux-kernel@vger.kernel.org, Boris Brezillon , Marek Vasut , Brian Norris , Richard Weinberger , David Woodhouse Subject: [PATCH] mtd: nand: wait for tWHR after NAND_CMD_STATUS / NAND_CMD_READID Date: Tue, 26 Sep 2017 12:39:24 +0900 Message-Id: <1506397164-3648-1-git-send-email-yamada.masahiro@socionext.com> List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Read Status and Read ID require tWHR before reading the first data. Insert a very short wait to make sure to meet the spec. I have not seen any problem report for now, but nand_command() and nand_command_lP() are generic hooks, so it makes sense to implement fail-safe code here. Signed-off-by: Masahiro Yamada --- drivers/mtd/nand/nand_base.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index b1cf32c..55c0ba5 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -742,9 +742,12 @@ static void nand_command(struct mtd_info *mtd, unsigned int command, case NAND_CMD_ERASE1: case NAND_CMD_ERASE2: case NAND_CMD_SEQIN: + case NAND_CMD_SET_FEATURES: + return; + case NAND_CMD_STATUS: case NAND_CMD_READID: - case NAND_CMD_SET_FEATURES: + ndelay(200); /* tWHR */ return; case NAND_CMD_RESET: @@ -871,9 +874,12 @@ static void nand_command_lp(struct mtd_info *mtd, unsigned int command, case NAND_CMD_ERASE1: case NAND_CMD_ERASE2: case NAND_CMD_SEQIN: + case NAND_CMD_SET_FEATURES: + return; + case NAND_CMD_STATUS: case NAND_CMD_READID: - case NAND_CMD_SET_FEATURES: + ndelay(200); /* tWHR */ return; case NAND_CMD_RNDIN: -- 2.7.4