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Re: Strataflash mapping problem
- From: Gary Thomas <gary at mlbassoc dot com>
- To: Jonathan Larmour <jifl at eCosCentric dot com>
- Cc: Enric Bel Prim <ebp at dimat dot es>,"'ecos-devel at sources dot redhat dot com'" <ecos-devel at sources dot redhat dot com>
- Date: Tue, 17 Feb 2004 07:08:24 -0700
- Subject: Re: Strataflash mapping problem
- Organization: MLB Associates
- References: <01C3F48E.BB02C480.ebp@dimat.es> <40313300.50206@eCosCentric.com>
On Mon, 2004-02-16 at 14:15, Jonathan Larmour wrote:
> Enric Bel Prim wrote:
> > Hi, again.
> > Yes, I agree with Jeffrey Daly that CYGNUM_FLASH_DEVICES should be the real
> > number of flash devices (4 in my platform), and CYGNUM_FLASH_WIDTH should
> > be the number of bits in each device (16 in my platform). But
> > CYGNUM_FLASH_INTERLEAVE should be 1 for my platform (16 bits devices
> > located in a 16 bit expansion bus of IXP425) and never equal to
> > CYGNUM_FLASH_DEVICES (as is defined in line 95 in strata.h)....
> > Finally I'm considering using the generic driver for the Intel 28fXXX
> > devices instead of the Intel strata to acces the Intel Strata Flash devices
> > of my platform.
> >
> > The 28fXXX driver requires the following settings:
> >
> > // Platform code must define the below
> > // #define CYGNUM_FLASH_INTERLEAVE : Number of interleaved devices (in
> > parallel)
> > // #define CYGNUM_FLASH_SERIES : Number of devices in series
> > // #define CYGNUM_FLASH_WIDTH : Width of devices on platform
> > // #define CYGNUM_FLASH_BASE : Address of first device
> >
> > For my platform I will set: (CYGNUM_FLASH_INTERLEAVE = 1,
> > CYGNUM_FLASH_SERIES = 4, CYGNUM_FLASH_WIDTH = 16, CYGNUM_FLASH_BASE =
> > 0x50000000)
> > I think CYGNUM_FLASH_SERIES will solve my flash mapping problems??? I
> > wonder why the strata flash driver doesn't allow this setting!!.
>
> Because no-one has implemented it :-).
Which mostly means that we (collectively) haven't seen a board with
devices arranged this way.
>
> > Does anybody know if I can use the 28fXXX driver to acces Intel Strata
> > Flash devices? I mean, will I loose some functionality/feature of the
> > Strata devices if I use the generic 28fXXX driver?
>
> I don't know, but if you look at where CYGNUM_FLASH_SERIES is mentioned in
> the 28fxxx driver, you'll see it should be pretty easy to bring the same
> ideas over into the strata driver if you needed to.
>
> Given the buffered write support is broken, I don't perceive any real
> difference in functionality between the drivers, but I haven't looked in
> detail.
IIRC, the 28Fxxx driver is somewhat newer and has better device support.
If changes are to be made, it would be best to put them into this
driver.
--
Gary Thomas <gary@mlbassoc.com>
MLB Associates