From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from guitar.tcltek.co.il ([192.115.133.116] helo=mx.tkos.co.il) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Yk7kD-0005Do-0s for linux-mtd@lists.infradead.org; Mon, 20 Apr 2015 09:11:59 +0000 Date: Mon, 20 Apr 2015 12:11:30 +0300 From: Baruch Siach To: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= Subject: Re: i.MX25 NFC with 8 bit ecc strength Message-ID: <20150420091130.GD5428@tarshish> References: <20150420045614.GC5428@tarshish> <20150420073702.GA2552@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20150420073702.GA2552@pengutronix.de> Cc: Shawn Guo , linux-mtd@lists.infradead.org, Sascha Hauer List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi Uwe, On Mon, Apr 20, 2015 at 09:37:02AM +0200, Uwe Kleine-König wrote: > On Mon, Apr 20, 2015 at 07:56:14AM +0300, Baruch Siach wrote: > > I'm trying to get nand_ecclayout right on i.MX25 with the Micron > > MT29F8G08ABABA (page size: 4096, oob size: 224). The large OOB size allows > Just for me to understand your plan: To support the big ecc variant you > need another set of struct nand_ecclayout. The expectation for your > flash would be: > > .eccpos = { 8, ... 25, > 34, ... 51, > 60, ... 77, > 86, ... 103, > 112, ... 129, > 138, ... 155, > 164, ... 181, > 190, ... 207 } > > right? According to the dump below (28 bytes interval) it should be off by one: eccpos = { 7, ... 24, 35, ... 52, 63, ... 80, 91, ... 108, 119, ... 136, 147, ... 164, 175, ... 192, 203, ... 220 }; > > using hardware ecc strength of 8bit per ecc step (512 bytes). The mxc_nand > > driver code (get_eccsize()) and the reference manual seems to indicate > > that enabling 8 bit ecc mode requires 26 oob bytes per ecc step. However, > > this seems to contradict the actual hardware test as the shown in the dump > > below of a zero filled page + oob: > > > > # hexdump -C dump4 > > 00000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| > > * > > 00001000 ff ff ff ff ff ff ff 91 c4 45 be 32 45 6f 5d b1 |.........E.2Eo].| > > 00001010 b1 b9 13 61 59 7d 42 58 eb ff ff ff ff ff ff ff |...aY}BX........| > > 00001020 ff ff ff 91 c4 45 be 32 45 6f 5d b1 b1 b9 13 61 |.....E.2Eo]....a| > > 00001030 59 7d 42 58 eb ff ff ff ff ff ff ff ff ff ff 91 |Y}BX............| > > 00001040 c4 45 be 32 45 6f 5d b1 b1 b9 13 61 59 7d 42 58 |.E.2Eo]....aY}BX| > > 00001050 eb ff ff ff ff ff ff ff ff ff ff 91 c4 45 be 32 |.............E.2| > > 00001060 45 6f 5d b1 b1 b9 13 61 59 7d 42 58 eb ff ff ff |Eo]....aY}BX....| > > 00001070 ff ff ff ff ff ff ff 91 c4 45 be 32 45 6f 5d b1 |.........E.2Eo].| > > 00001080 b1 b9 13 61 59 7d 42 58 eb ff ff ff ff ff ff ff |...aY}BX........| > > 00001090 ff ff ff 91 c4 45 be 32 45 6f 5d b1 b1 b9 13 61 |.....E.2Eo]....a| > > 000010a0 59 7d 42 58 eb ff ff ff ff ff ff ff ff ff ff 91 |Y}BX............| > > 000010b0 c4 45 be 32 45 6f 5d b1 b1 b9 13 61 59 7d 42 58 |.E.2Eo]....aY}BX| > > 000010c0 eb ff ff ff ff ff ff ff ff ff ff 91 c4 45 be 32 |.............E.2| > > 000010d0 45 6f 5d b1 b1 b9 13 61 59 7d 42 58 eb ff ff ff |Eo]....aY}BX....| > > > > As you can easily see, ecc steps start at 28 bytes interval, with 18 > > bytes for ecc (matches documentation), and 10 bytes free. > How did you extract this page+oob from the nand flash? From Linux I > assume? Got it form nanddump using: nanddump -s 5238784 -f dump4 -o /dev/mtd2 > Can you try from barebox something like: > > mw -w 0xbb001e08 0x0000 # READ0 > mw -w 0xbb001e1c 0x01 # CMD cycle > mw -w 0xbb001e06 0x00 # Address = 0 > mw -w 0xbb001e1c 0x02 # Address cycle > mw -w 0xbb001e1c 0x02 # Address cycle > mw -w 0xbb001e1c 0x02 # Address cycle (do we need three? [1]) > mw -w 0xbb001e04 0x00 > mw -w 0xbb001e1c 0x08 # NAND OUTPUT > md -w 0xbb000000+0x10f0 > > with ecc being disabled (i.e. CONFIG1, bit 3 = 0). Does this show the 28 > bytes offset, too? I (hopefuly) disabled ECC with: mw -w 0xbb001e1a 0x0010 Then, for the same page (using three address cycles, 0xff, 0x04, 0x00), I got all zeros up to 0xbb001000 (inclusive), and then: bb001010: 0000 0000 0000 0000 0000 ffff 28a7 428a .............(.B bb001020: 89fa 2cd4 4640 560a 2634 ac7e e5d8 20ea ...,@F.V4&~.... bb001030: caaa c809 0195 8411 6972 6bfc 84d6 10af ........ri.k.... bb001040: 0000 0000 0000 0000 0000 0000 0000 0000 ................ bb001050: 0000 0000 0000 0000 0000 ffff f1da 19c3 ................ bb001060: 21b2 0832 09c6 3c55 638c 3bb8 fd54 2983 .!2...U<.c.;T..) bb001070: 8325 6d98 0814 0d64 ee73 675e 1943 5cf2 %..m..d.s.^gC..\ bb001080: 0000 0000 0000 0000 0000 0000 0000 0000 ................ bb001090: 0000 0000 0000 0000 0000 ffff c1bc 31fe ...............1 bb0010a0: 16ee ab6b 34a5 acad 0771 048c ac58 3f19 ..k..4..q...X..? bb0010b0: b699 a88f eb5a 00ae 7e3c 9c6d 2ba8 d72e ....Z...<~m..+.. bb0010c0: 0000 0000 0000 0000 0000 0000 0000 0000 ................ bb0010d0: 0000 0000 0000 0000 0000 ffff ae14 06c7 ................ bb0010e0: 89b9 eb67 00d0 3648 daeb 15f5 77ca 8c09 ..g...H6.....w.. I'm not sure what to do with that. Thanks, baruch -- http://baruch.siach.name/blog/ ~. .~ Tk Open Systems =}------------------------------------------------ooO--U--Ooo------------{= - baruch@tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -