Hi,

I'm working on a custom board design based on AT91SAM9G45-EKES and using Linux 3.0.4.

I'm creating a user space utility for working with the nand flash. When I try to read a partition of the nand flash as a character device, then I'm receiving alternate bytes.

For example, if Nand partition contains:
0x01 0x02 0x03 0x04 0x05 0x06 0x07 0x08....
I'm getting
0x01 0x03 0x05 0x07....

Did anyone have similar issues? Can anyone point out what may be going wrong?

-PJ

Hi,

I probed into the nand driver and found out that it is being configured for 8 bit and not 16 bits (as it should be). I set the variable in ek_nand_data.bus_width_16 as 1, even then the probe function in the atmel_nand.c configures it for 8 bits.

Any idea what else has to be set, to make the nand driver realize that it is 16 bit NAND.

-PJ

This was a really stupid one. I dont know how I missed it.

in arch/arm/mach-at91/board-sam9m10g45ek.c
in function ek_add_device_nand()
change
ek_nand_data.bus_width_16=board_have_nand_16bit(); to
ek_nand_data.bus_width_16=1;

-PJ

Hi,

In fact, if you are using a custom board, it is maybe better to create another board file...
So, in board-sam9m10g45ek.c file, it has been decided to use an indication from the "system_rev" variable that is passed to the Linux kernel by the bootloader through the ATAG mechanism. It replaces the old Kconfig value.
If you use this board file and place a "1" at bit 31 of the system_rev, your system should understand that your NAND is connected in 16bits mode.

But for sure, your modification will work for your custom board.

Best regards,

Thanks nferre.

I would try that in my spare time and will report back the results.

-PJ