i.MX25 NFC with 8 bit ecc strength
Uwe Kleine-König
u.kleine-koenig at pengutronix.de
Mon Apr 20 00:37:02 PDT 2015
Hello Baruch,
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?
> 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? 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?
> Has anyone ever tried using 8 bit ecc mode with any variant of the
> i.MX NFC?
I'm not aware we at Pengutronix already did.
Best regards
Uwe
[1] it doesn't seem trivial to get a datasheet from Micron for your
chip. On the webpage I end up at a "Document Request Form" where I
need to fill out quantities per month with a minimal value of 1k and
if we have an NDA.
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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