Hi all,
I ran into a weird problem when I tried to access a static (NV) ram attached to
the localbus of a '5200 using Wolfram's mtd-ram OF driver (on a stock 2.6.29.1
kernel). The 512k ram chip is connected in 16-bit mode to cs1. the of entry
reads
nv...@1,0 {
compatible = "mtd-ram";
reg = <1 0x0 0x00080000>; // 512 kB
bank-width = <2>;
device-width = <2>;
#size-cells = <1>;
#address-cells = <1>;
};
For the test I created a "pattern file" which is filled with the unsigned long
0x0055aaff. Using the Abatron BDI3000, I can write the pattern file to the ram
and re-read it without problems. The same applies to u-boot (write ram via
tftp, dump contents).
In Linux, when I write the file to /dev/mtdx, the last dword of each block is
broken, e.g. when running "dd if=pattern of=/dev/mtd5 bs=512" the dword's at
offset 0x1fc, 0x3fc, ... are 0x0000aaaa (instead of 0x0055aaff), if I use
bs=1024 the dwords at 0x3fc, 0x7fc, ... show this value, if I use bs=4096 the
dword at 0xffc shows this value, etc. I looked at the CS/WR lines with a
scope, and I couldn't see anything special. The timing should be fine, as
u-boot uses the same as Linux.
Any idea what goes wrong here? I guessed I missed something in the LPB setup...
Thanks in advance,
Albrecht.
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