* Mohammed, Afzal <afzal@xxxxxx> [120613 06:10]: > Hi Tony, > > On Wed, Jun 13, 2012 at 17:32:09, Tony Lindgren wrote: > > * Mohammed, Afzal <afzal@xxxxxx> [120612 22:24]: > > > Hi Jon, > > > > > > On Tue, Jun 12, 2012 at 23:10:01, Hunter, Jon wrote: > > > > > Right but potentially, this could be done by the driver. > > > > > > I do not think it is practically possible. Please see timing calculations > > > in arch/arm/mach-omap2/gpmc-*, the way it is done for different > > > peripherals are different, and we cannot expect gpmc driver to do those as > > > that would require gpmc driver being aware of type of peripheral connected. > > > > > > And all those gpmc-* timing calculation needs to be done before driver > > > is ready, they rely on functions like gpmc_get_fclk_rate(), which in turn > > > requires the clk rate to be available before driver is probed. > > > > Yeah I also think the GPMC code should handle the L3 timings, and dynamically > > calculate them for DVFS when L3 frequency changes. Does the GPMC have enough > > information now to do that? > > Do you mean that gpmc driver should have the capability to calculate peripheral > timings at runtime based on frequency ?, I am not sure how this can be handled > by gpmc driver as calculation for different peripherals are done in different > way, requiring gpmc driver to know about connected peripheral, that would imply > that gpmc driver would not be peripheral agnostic. > > Or else some sort of a callback to be used ? Oops yeah right, we have some platform_retime functions that are in the driver platform init code. It would be best that the drivers can do the recalculation with no platform init code callbacks needed. > Out of the 20,14 are depending on bootloader, both omap3evm & beagle has been > converted to utilize runtime calculation, but for other 12 boards, first > we need to get values used by bootloader (those include peripherals that doesn't > have gpmc-* helpers), then derive it based on expression, after that only, we > will have information to achieve it and those are the ones that I do not > have access to. It's OK to use fixed timings as long as we disable L3 scaling. Some of these values we'll probably never be able to calculate dynamically. Regards, Tony -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
