On Sun, Dec 16, 2007 at 05:32:51PM +0000, Adrian McMenamin wrote: > On Sun, 2007-12-16 at 18:50 +0900, Paul Mundt wrote: > > > + for (count = 0xa0000000; count < 0xa0200000; count += 4) > > > + ctrl_inl(count); > > > > Er? This ranged dummy reading of the P2 space needs some explanation. The > > GD-ROM isn't even mapped in to this space, so this seems like a hack to > > either work around a timing issue or a write ordering problem. > > I'll confess to not knowing what it's up to here either, other than it > looks like a mechanism to cause a G1 bus reset. This is a progressive > read of the Boot ROM area and that is all under G1 control (as is the GD > Rom obviously) > Ok, then this should be moved out to a g1_bus_reset() or something similar with a comment explaining what it's doing, that way it can be trivially reworked if a saner method of forcing a G1 reset is discovered. While I realize that this is all undocumented and based entirely on reverse engineering, you should at least verify that that's precisely what is going on, and that this is not just a precaution for flushing posted writes. You can test that by removing the loop and doing a dummy read after your write (to the same register, rather than the entire ROM space). If it's a posting issue, then you will have to do your own read/write_reg routines that handle the flush. - To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
