From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from arroyo.ext.ti.com ([192.94.94.40]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Whcck-0006Rx-2O for linux-mtd@lists.infradead.org; Tue, 06 May 2014 10:29:27 +0000 From: Pekon Gupta To: Brian Norris , Artem Bityutskiy Subject: [PATCH v2] mtd: nand: Fix problem with NAND_CMD_RNDOUT (05h-E0h) Date: Tue, 6 May 2014 15:58:40 +0530 Message-ID: <1399372120-24089-1-git-send-email-pekon@ti.com> MIME-Version: 1.0 Content-Type: text/plain Cc: Marek Belisko , Samuel Egli , linux-mtd , Pekon Gupta , Steven Kipisz , Stefan Roese , Bacem Daassi List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Bacem Daassi Though the NAND_CMD_READ "Page Read" command expects the full address footprint (2bytes for column address + 3bytes for row address). But once the page is loaded into the read buffer, NAND_CMD_RNDOUT (05h-E0h) also called "Random Data Output" command expects to see only the column address that should be addressed within the already loaded page present in read buffers. Only 2 address cycles with ALE active should be provided between the 05h and E0h So expected sequence for NAND_CMD_RNDOUT is <05h> Though most NAND Devices mentioned above tend to work even if extra cycles of page-address is issued between <05h> .... command. But some Spansion and Hynix devices break on this non-compliance. The same issue has been reported by Bacem Daassi http://e2e.ti.com/support/arm/sitara_arm/f/791/t/259699.aspx This patch fixes nand_command for all vendors devices as datasheet of all devices expect same sequence. +--------+------------------------+--------------------------------------------- |Vendor | Datasheet/Part# | Reference +--------+------------------------+--------------------------------------------- |Spansion| S34ML{01|02|04}G2 | Figure 6.12 Random Data Output In a Page |Micron | MT29F{16|32|64|128}G08A| Figure 47: CHANGE READ COLUMN (05h-E0h) Operation |Macronix| MX30LF1G08AA | Figure 10. AC Waveforms for Random Data Output |Toshiba | TC58NVG1S3ETAI0 | Figure Column Address Change in Read Cycle Timing Diagram (2/2) +--------+------------------------+--------------------------------------------- Reported-by: Bacem Daassi Reported-by: Marek Belisko Reported-by: Steven Kipisz Signed-off-by: Pekon Gupta --- changes v1->v2: fixed both nand_command() and nand_command_lp() drivers/mtd/nand/nand_base.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index 9d01c4d..c11565f 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -595,7 +595,7 @@ static void nand_command(struct mtd_info *mtd, unsigned int command, chip->cmd_ctrl(mtd, column, ctrl); ctrl &= ~NAND_CTRL_CHANGE; } - if (page_addr != -1) { + if (page_addr != -1 && command != NAND_CMD_RNDOUT) { chip->cmd_ctrl(mtd, page_addr, ctrl); ctrl &= ~NAND_CTRL_CHANGE; chip->cmd_ctrl(mtd, page_addr >> 8, ctrl); @@ -688,7 +688,7 @@ static void nand_command_lp(struct mtd_info *mtd, unsigned int command, ctrl &= ~NAND_CTRL_CHANGE; chip->cmd_ctrl(mtd, column >> 8, ctrl); } - if (page_addr != -1) { + if (page_addr != -1 && command != NAND_CMD_RNDOUT) { chip->cmd_ctrl(mtd, page_addr, ctrl); chip->cmd_ctrl(mtd, page_addr >> 8, NAND_NCE | NAND_ALE); -- 1.8.5.1.163.gd7aced9