[U-Boot-Users] [patch] add support for "eeprom info"

Mike Frysinger
2008-01-25T13:33:05Z

On Thursday 24 January 2008, Wolfgang Denk wrote:
> 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.

OK, thanks for the explanation. this is much before my time ;).

at the moment, the Blackfin SPI flash driver hides all of the erasing/writing
stuff for the user so that it integrates easily into the eeprom command. i'm
going to guess that you dont like the sound of that at all ;).
-mike
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