Dear "Choe, Hyun-ho", In message <[EMAIL PROTECTED]> you wrote: > I did several tests for my b'd that has CFI Nor erase/write problem. > > My main problem is that flash_toggle() function doesn't work properly, > it always returns 0 even while bus writing operation is proceeding. > I mean, toggle bit doesn't toggle for each read operation. (refer to > drivers/mtd/cfi_flash.c)
Similar problems have been reported before - please see for example http://lists.denx.de/pipermail/u-boot/2008-October/042036.html > I found two workarounds. > > First, small waiting between each read. So, following code doesn't work. > > <SNIP> > retval = flash_read16(addr) != flash_read16(addr); > <SNIP> Eventually you are not performing atomic 16 bit read operations. > But, following code does work. > > <SNIP> > u16 d = flash_read16(addr); > udelay(1); > u16 t = flash_read16(addr); > retval = d != t; Hm... a plain delay would probably not change this behaviour unless you have another problem. > I don't know exactly that this is caused by specific bus access > mechanism, or simply chip silicon bug. I think the problem is that for some reason flash_read16() might not result in 16bit bus accesses. Do you have a chance to verify this suspicion, for example with a logic analyzer? Best regards, Wolfgang Denk -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: [EMAIL PROTECTED] Never ascribe to malice that which can adequately be explained by stupidity. _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
