Working with Intel 440BX Bios socket & flash parts

[roger <roger@eskimo.com>]

Scenario is an Intel 440BX/GX Motherboard with a STMicroelectronics 256k
Flash Part within the bios socket.

After loading the l440gx module, I can see:
/dev/mtd0
/dev/mtd0ro
/dev/mtdblock0


However, every time I try to access /dev/mtd0 in write mode, I get a
permission denied error.

Using stephan's work with the LinuxBios flashrom utility, flashrom will
"enable writing".  And then, I can view the contents of the bios
of /dev/mtd0 (ie. hexedit /dev/mtd0 or dd if=/dev/mtd0 of=bios.bin)
(Without using flashrom, /dev/mtd0 is just showing blank or "FF"
values.)

STMicroelectronics 256k Flash Part

# mtd_debug info /dev/mtd0
mtd.type = (unknown type - new MTD API maybe?)
mtd.flags = MTD_CAP_ROM
mtd.size = 1048576 (1M)
mtd.erasesize = 1048576 (1M)
mtd.writesize = 1 
mtd.oobsize = 0 
mtd.ecctype = MTD_ECC_NONE
regions = 0


If I'm not mistaken, I used to be able to dd if=/dev/null of=/dev/mtd0
bios flash parts of these with mtd a couple of years ago.

After putting a DOC2000 into the 32 DIP socket, I can write to the
DOC2000 modules without problem after using flashrom to enable writing
(or basically viewing or unhiding).

Am I forgetting something here?  Is there something more to writing to
the STMicroelectronics or Atmel at29c020 flash parts?


(On more minor note, I had to set the "clocksource=tsc" because the
linux kernel was setting to acpi_pm.  On modprobing l440gx, the clock
would stop with clocksource=acpi_pm.)

 
--
Roger
http://www.eskimo.com/~roger/index.html
Key fingerprint = 8977 A252 2623 F567 70CD 1261 640F C963 1005 1D61

Thu Apr 19 02:59:17 PDT 2007