Re: [PATCH v3] mtd/nand : workaround for Freescale FCM to support large-page Nand chip

=E4=BA=8E 2011=E5=B9=B408=E6=9C=8819=E6=97=A5 01:00, Matthieu CASTET =E5=86=
=99=E9=81=93:

b35362@freescale.com a =C3=A9crit :

quoted

From: Liu Shuo<redacted>

Freescale FCM controller has a 2K size limitation of buffer RAM. In or=

der

quoted

to support the Nand flash chip whose page size is larger than 2K bytes=

,

quoted

we divide a page into multi-2K pages for MTD layer driver. In that cas=

e,

quoted

we force to set the page size to 2K bytes. We convert the page address=

 of

quoted

MTD layer driver to a real page address in flash chips and a column in=

dex

quoted

in fsl_elbc driver. We can issue any column address by UA instruction =

of

quoted

elbc controller.

Why do you need to do that ?

When mtd send you a 4k page, why can't you write it by 2*2k pages write=

 ?
1. It's easy to implement.
2. We don't need to move the data in buffer more times, because we
want to use the HW_ECC.

In flash chip per Page:
----------------------------------------------------------------
| first data | first oob | second data | second oob |
----------------------------------------------------------------

Even better send the first 2K and then if your controller allow it send=

 the

remaining 2K without command/address phase.

The elbc controller don't allow that.
I have to send twice Program CMD for writing the whole 4KB data.

Matthieu