[U-Boot-Users] environment not being used

[Shamile Khan <shamile@edgewater.ca>]

On Wed, 2004-02-04 at 15:30, Wolfgang Denk wrote:
> In message <1075855660.7664.95.camel@localhost.localdomain> you wrote:
> > 
> > Just as a follow up, I conclude that U-boot treats flash reads exactly
> > as sdram reads i.e. 32-bit accesses. So its not just about the
> 
> This is not correct.
> 
> U-Boot accesses the flash just the way how you configure your  memory
> controller for flash accesses.

Exactly. The memory controller is in FPGA. Its been configured to have a
data bus width of 8 bits to the flash memory device. Consequently if a
32 bit access is requested, the first 8 bits are fine and the rest are
garbage.

> 
> > to flash e.g md, imiinfo, bootm etc. A hardware fix (an 8-bit bus to our
> > byte-mode flash chip) seems like the right way to go.
> 
> Either you or me must  be  missing  something.  Why  don't  you  just
> configure U-Boot for a 8 bit flash device then?

I do have the flash device configured as an 8-bit device and flash
memory writes are for byte mode in the flash driver. So writes to flash
are fine as long as I use cp.b instead of just cp. 

As far as reads are concerned, since the flash device is in byte mode I
can only access 8 bits in one flash memory read cycle. However U-boot
commands like md, bootm, iminfo, crc32 etc access 32 bits in one flash
memory read cycle (md.b is an exception).

So those commands would work if I have for example 4 byte-mode flash
devices and the memory controller concatenates the data thats read from
those devices. But I only have one byte-mode flash device.

> Best regards,
> 
> Wolfgang Denk
> 
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