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From: "Gupta, Pekon" <pekon@ti.com>
To: David Jander <david.jander@protonic.nl>, Brian Norris
 <computersforpeace@gmail.com>
Subject: RE: [FRC] [PATCH] MTD: nand_base.c: Enable support for Samsung
 E-die SLC NAND
Date: Mon, 30 Jun 2014 11:06:39 +0000
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Cc: Ted Juan <ted.juan@gmail.com>,
 "sjhill@realitydiluted.com" <sjhill@realitydiluted.com>,
 "tglx@linutronix.de" <tglx@linutronix.de>,
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Hi David,

>From: David Jander [mailto:david.jander@protonic.nl]
[...]
>
>P.S.: Anyone care to give comment on my patch? Not that you two effectivel=
y
>hijacked this thread for only slightly tangentially related issues... ;-)
>
Sorry for diverting from the main patch discussion, somehow I'm unable to
find the original PATCH email from mtd-list.
As per Samsung Device (K9F1G08U0E) datasheet, which is
"1Gb E-die SLC NAND Flash". This device support 'Random Input' (0x85) comma=
nd.
This means driver can change the column-address during page-program
operation and write to any partial page in between. Isn't that sufficient
to support subpage writes ?

Earlier implementation of nand_write_subpage_hwecc() has some limitations,
I have recently sent a patch-series [1] which uses alternate approach, can =
you
check if subpage writes work with this.
Also which controller driver are you using for this device ? There may be s=
ome
controller limitation too, prohibiting use of subpages.


with regards, pekon

[1] http://lists.infradead.org/pipermail/linux-mtd/2014-June/054446.html