On Thursday 04 January 2007 10:23, Wolfgang Denk wrote:
Wolfgang Denk wrote:
Now this is what I want to understand. What exactly is the "potential problem"?
That's the issue in the flash 'Spinsion S29GL064M90TFIR6' with x16 connection. After running flash_read_jedec_ids(), any follow CFI query command will get the data with high 8bit = 0xff, but the low 8bit is valid. And if we only read low 8bit, we'll get the 0xff too. In addition, the second follow CFI query command has no that issue. So, I read the full 16bit date and only take the valid low 8bit.
etc. etc.
I didn't see any new facts in your current posting. My position has not changed either: I don't see how your character-wise copy using memcpy() would be different from accessing the flash through a uchar pointer; also I still think that if the compiler version changes behaviour then we don't really understand what's going on here.
Maybe Tolunay or Stefan can comment now that both are back from their Xmas breaks; they both know the CFI driver much better than me.
What I noticed after looking at the flash access functions like flash_read_uchar() is that no access macros and even no volatile pointer access is used to read from the flash. This looks like a potential problem, that can show when using different compiler versions.
Please find attached a small patch that adds fixes this potential problem for the 3 functions flash_read_uchar/ushort/long. Please give it a try and let me know if this changed the behavior somehow.
Thanks.
Best regards, Stefan