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From: Wolfgang Denk <wd@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot-Users] [patch] add support for "eeprom info"
Date: Thu, 24 Jan 2008 12:31:36 +0100	[thread overview]
Message-ID: <20080124113136.8DADF24788@gemini.denx.de> (raw)
In-Reply-To: Your message of "Thu, 24 Jan 2008 04:13:03 EST." <200801240413.04318.vapier@gentoo.org>

In message <200801240413.04318.vapier@gentoo.org> you wrote:
> 
> > I think you are doing something wrong when you try to use "eeprom" to
> > access "SPI flash" - these are differnt entities...
> 
> let's make sure we're talking about the same thing.  SPI flashes are eeproms 
> that have a SPI interface.  so Spansion's S25FLxxxx, ST's m25pxtmels 
> AT45DBxxxx, Winbond's W25Xxx/W25Pxx, and such.  they need to be erased before 
> writing, are split up into some unit size, etc...  all SPI flashes nowadays 
> conform to the JEDEC standard (JEP106) which allows for querying of 
> manufacturer/device ids so that they can be dynamically detected.  sounds to 
> me like "eeprom" is the correct interface for utilizing these devices.

Sounds to me as if you were talking about flash devices with a SPI bus
interface.

The original SPI eeprom support was implemented som 7+ years ago  for
the  Siemens  CCM  board;  this  is  where  the "CONFIG_SPI" stuff in
common/cmd_eeprom.c  comes  from,  and  this  was  supported  by  the
cpu/mpc8xx/spi.c SPI driver. Note that this was a real EEPROM device,
i.  e.  we just needed spi_read() and spi_write() functions to access
it. No erase, no sectors or any such stuff.

That was an EEPROM - what you have looks like a flash device to me.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
In the pitiful, multipage, connection-boxed form to which  the  flow-
chart  has  today  been  elaborated, it has proved to be useless as a
design tool -- programmers draw flowcharts after, not before, writing
the programs they describe.                        - Fred Brooks, Jr.

  reply	other threads:[~2008-01-24 11:31 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-01-23 16:13 [U-Boot-Users] [patch] add support for "eeprom info" Mike Frysinger
2008-01-23 21:06 ` Wolfgang Denk
2008-01-23 21:15   ` Mike Frysinger
2008-01-23 21:23     ` Wolfgang Denk
2008-01-23 22:29       ` Mike Frysinger
2008-01-24  0:44         ` Wolfgang Denk
2008-01-24  3:39           ` Mike Frysinger
2008-01-24  4:24             ` Ben Warren
2008-01-24  5:17               ` Mike Frysinger
2008-01-24 11:13                 ` Wolfgang Denk
2008-01-25 13:31                   ` Mike Frysinger
2008-01-24  9:13           ` Mike Frysinger
2008-01-24 11:31             ` Wolfgang Denk [this message]
2008-01-25 13:33               ` Mike Frysinger
2008-01-25 15:09                 ` Wolfgang Denk
2008-01-25 16:02                   ` Mike Frysinger
2008-01-25 16:54                     ` J. William Campbell
2008-01-25 17:21                       ` Mike Frysinger

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