From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from rn-out-0910.google.com ([64.233.170.190]) by bombadil.infradead.org with esmtp (Exim 4.68 #1 (Red Hat Linux)) id 1KfEkO-0002ee-Tk for linux-mtd@lists.infradead.org; Mon, 15 Sep 2008 14:08:13 +0000 Received: by rn-out-0910.google.com with SMTP id m7so1453040rnd.3 for ; Mon, 15 Sep 2008 07:08:12 -0700 (PDT) Message-ID: <48CE6C43.8050500@gmail.com> Date: Mon, 15 Sep 2008 16:08:03 +0200 From: Karl Beldan MIME-Version: 1.0 To: linux-mtd@lists.infradead.org Subject: Re: [PATCH] [MTD] [NAND] nand_base.c: reset chip first References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: David.Woodhouse@intel.com List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Some chips require a RESET after power-up (e.g. Micron MT29FxGxxxxx). The first command sent is NAND_CMD_READID. Issue a NAND_CMD_RESET in nand_scan_ident before reading the device id. Tested with an MT29F4G08AAC. Signed-off-by: Karl Beldan --- Prior to resetting, the chip gives a correct first ID byte though. Resubmitted without(?) mail client formatting. diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index d1129ba..2cfac9b 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -2318,6 +2318,12 @@ static struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd, /* Select the device */ chip->select_chip(mtd, 0); + /* + * Reset the chip, required by some chips (e.g. Micron MT29FxGxxxxx) + * after power-up + */ + chip->cmdfunc(mtd, NAND_CMD_RESET, -1, -1); + /* Send the command for reading device ID */ chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1); @@ -2488,6 +2494,8 @@ int nand_scan_ident(struct mtd_info *mtd, int maxchips) /* Check for a chip array */ for (i = 1; i < maxchips; i++) { chip->select_chip(mtd, i); + /* See comment in nand_get_flash_type for reset */ + chip->cmdfunc(mtd, NAND_CMD_RESET, -1, -1); /* Send the command for reading device ID */ chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1); /* Read manufacturer and device IDs */