From patchwork Mon Mar 4 16:47:35 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Uwe_Kleine-K=C3=B6nig?= X-Patchwork-Id: 224764 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:4978:20e::2]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 93C172C02FC for ; Tue, 5 Mar 2013 03:48:56 +1100 (EST) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1UCYYR-00075B-3o; Mon, 04 Mar 2013 16:47:59 +0000 Received: from metis.ext.pengutronix.de ([2001:6f8:1178:4:290:27ff:fe1d:cc33]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1UCYYJ-00072x-O5 for linux-mtd@lists.infradead.org; Mon, 04 Mar 2013 16:47:57 +0000 Received: from dude.hi.pengutronix.de ([2001:6f8:1178:2:21e:67ff:fe11:9c5c]) by metis.ext.pengutronix.de with esmtp (Exim 4.72) (envelope-from ) id 1UCYYD-0004B7-Kp; Mon, 04 Mar 2013 17:47:45 +0100 Received: from ukl by dude.hi.pengutronix.de with local (Exim 4.80) (envelope-from ) id 1UCYYD-0003Qj-Jl; Mon, 04 Mar 2013 17:47:45 +0100 From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= To: linux-mtd@lists.infradead.org Subject: [PATCH v2] mtd/nand: don't use {read, write}_buf for 8-bit transfers Date: Mon, 4 Mar 2013 17:47:35 +0100 Message-Id: <1362415655-13073-1-git-send-email-u.kleine-koenig@pengutronix.de> X-Mailer: git-send-email 1.8.2.rc2 In-Reply-To: <1362414924-27506-1-git-send-email-u.kleine-koenig@pengutronix.de> References: <1362414924-27506-1-git-send-email-u.kleine-koenig@pengutronix.de> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2001:6f8:1178:2:21e:67ff:fe11:9c5c X-SA-Exim-Mail-From: ukl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-mtd@lists.infradead.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130304_114752_095741_0B3D0632 X-CRM114-Status: GOOD ( 22.87 ) X-Spam-Score: -2.5 (--) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-2.5 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.6 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: kernel@pengutronix.de X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-mtd" Errors-To: linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org According to the Open NAND Flash Interface Specification (ONFI) Revision 3.1 "Parameters are always transferred on the lower 8-bits of the data bus." for the Get Features and Set Features commands. So using read_buf and write_buf is wrong for 16-bit wide nand chips as they use I/O[15:0]. The Get Features command is easily fixed using 4 times the read_byte callback. For Set Features implement a new overwritable callback "write_byte". Still I expect the default to work just fine for all controllers. Signed-off-by: Uwe Kleine-König --- Notes: v1 got an Acked-by: Huang Shijie Changes since (implicit) v1, sent with Message-Id:1361977852-18233-1-git-send-email-u.kleine-koenig@pengutronix.de: - implement a new write_byte callback to also fix nand_onfi_set_features (instead of returning -ENOSUPP in v1) drivers/mtd/nand/nand_base.c | 60 +++++++++++++++++++++++++++++++++++++++++--- include/linux/mtd/nand.h | 3 +++ 2 files changed, 59 insertions(+), 4 deletions(-) diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index 3766682..956b499 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -205,6 +205,50 @@ static void nand_select_chip(struct mtd_info *mtd, int chipnr) } /** + * nand_write_byte - [DEFAULT] write single byte to chip + * @mtd: MTD device structure + * @byte: value to write + * + * Default function to write a byte to I/O[7:0] + */ +static void nand_write_byte(struct mtd_info *mtd, uint8_t byte) +{ + struct nand_chip *chip = mtd->priv; + + chip->write_buf(mtd, &byte, 1); +} + +/** + * nand_write_byte16 - [DEFAULT] write single byte to a chip with width 16 + * @mtd: MTD device structure + * @byte: value to write + * + * Default function to write a byte to I/O[7:0] on a 16-bit wide chip. + */ +static void nand_write_byte16(struct mtd_info *mtd, uint8_t byte) +{ + struct nand_chip *chip = mtd->priv; + + /* + * It's not entirely clear what should happen to I/O[15:8] when writing + * a byte. The ONFi spec (Revision 3.1; 2012-09-19, Section 2.16) reads: + * + * When the host supports a 16-bit bus width, only data is + * transferred at the 16-bit width. All address and command line + * transfers shall use only the lower 8-bits of the data bus. During + * command transfers, the host may place any value on the upper + * 8-bits of the data bus. During address transfers, the host shall + * set the upper 8-bits of the data bus to 00h. + * + * One user of the write_byte callback is nand_onfi_set_features. The + * four parameters are specified to be written to I/O[7:0], but this is + * neither an address nor a command transfer. Let's assume a 0 on the + * upper I/O lines is OK. + */ + chip->write_buf(mtd, (uint8_t[]){ byte, 0 }, 2); +} + +/** * nand_write_buf - [DEFAULT] write buffer to chip * @mtd: MTD device structure * @buf: data buffer @@ -2710,7 +2754,7 @@ static int nand_block_markbad(struct mtd_info *mtd, loff_t ofs) } /** - * nand_onfi_set_features- [REPLACEABLE] set features for ONFI nand + * nand_onfi_set_features - [REPLACEABLE] set features for ONFI nand * @mtd: MTD device structure * @chip: nand chip info structure * @addr: feature address. @@ -2720,12 +2764,15 @@ static int nand_onfi_set_features(struct mtd_info *mtd, struct nand_chip *chip, int addr, uint8_t *subfeature_param) { int status; + int i; if (!chip->onfi_version) return -EINVAL; chip->cmdfunc(mtd, NAND_CMD_SET_FEATURES, addr, -1); - chip->write_buf(mtd, subfeature_param, ONFI_SUBFEATURE_PARAM_LEN); + for (i = 0; i < ONFI_SUBFEATURE_PARAM_LEN; ++i) + chip->write_byte(mtd, subfeature_param[i]); + status = chip->waitfunc(mtd, chip); if (status & NAND_STATUS_FAIL) return -EIO; @@ -2733,7 +2780,7 @@ static int nand_onfi_set_features(struct mtd_info *mtd, struct nand_chip *chip, } /** - * nand_onfi_get_features- [REPLACEABLE] get features for ONFI nand + * nand_onfi_get_features - [REPLACEABLE] get features for ONFI nand * @mtd: MTD device structure * @chip: nand chip info structure * @addr: feature address. @@ -2742,6 +2789,8 @@ static int nand_onfi_set_features(struct mtd_info *mtd, struct nand_chip *chip, static int nand_onfi_get_features(struct mtd_info *mtd, struct nand_chip *chip, int addr, uint8_t *subfeature_param) { + int i; + if (!chip->onfi_version) return -EINVAL; @@ -2749,7 +2798,8 @@ static int nand_onfi_get_features(struct mtd_info *mtd, struct nand_chip *chip, memset(subfeature_param, 0, ONFI_SUBFEATURE_PARAM_LEN); chip->cmdfunc(mtd, NAND_CMD_GET_FEATURES, addr, -1); - chip->read_buf(mtd, subfeature_param, ONFI_SUBFEATURE_PARAM_LEN); + for (i = 0; i < ONFI_SUBFEATURE_PARAM_LEN; ++i) + *subfeature_param++ = chip->read_byte(mtd); return 0; } @@ -2804,6 +2854,8 @@ static void nand_set_defaults(struct nand_chip *chip, int busw) chip->block_markbad = nand_default_block_markbad; if (!chip->write_buf) chip->write_buf = busw ? nand_write_buf16 : nand_write_buf; + if (!chip->write_byte) + chip->write_byte = busw ? nand_write_byte16 : nand_write_byte; if (!chip->read_buf) chip->read_buf = busw ? nand_read_buf16 : nand_read_buf; if (!chip->scan_bbt) diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h index 7ccb3c5..8ee4ed1 100644 --- a/include/linux/mtd/nand.h +++ b/include/linux/mtd/nand.h @@ -419,6 +419,8 @@ struct nand_buffers { * flash device. * @read_byte: [REPLACEABLE] read one byte from the chip * @read_word: [REPLACEABLE] read one word from the chip + * @write_byte [REPLACEABLE] write a single byte to the chip on the + * low 8 I/O lines * @write_buf: [REPLACEABLE] write data from the buffer to the chip * @read_buf: [REPLACEABLE] read data from the chip into the buffer * @select_chip: [REPLACEABLE] select chip nr @@ -503,6 +505,7 @@ struct nand_chip { uint8_t (*read_byte)(struct mtd_info *mtd); u16 (*read_word)(struct mtd_info *mtd); + void (*write_byte)(struct mtd_info *mtd, uint8_t byte); void (*write_buf)(struct mtd_info *mtd, const uint8_t *buf, int len); void (*read_buf)(struct mtd_info *mtd, uint8_t *buf, int len); void (*select_chip)(struct mtd_info *mtd, int chip);