* Rajendra Nayak <rnayak@xxxxxx> [130318 01:25]: > On Friday 15 March 2013 09:50 PM, Tony Lindgren wrote: > > * Rajendra Nayak <rnayak@xxxxxx> [130315 05:31]: > >> On Thursday 14 March 2013 10:36 PM, Tony Lindgren wrote: > >>> * Rajendra Nayak <rnayak@xxxxxx> [130314 05:44]: > >>>> OMAP clock inits happen quite early, even before the slab is available. > >>>> As part of the clock init, the common clock core tries to cache parent > >>>> pointers (if not passed by the caller registering the clock) which > >>>> fails in case of OMAP since the slab isn't initied. > >>>> Without CONFIG_DEBUG_SLAB enabled, this just results in the common clock core > >>>> retrying the caching attempt at some point later. > >>>> However with CONFIG_DEBUG_SLAB enabled this results in a BUG() as reported > >>>> in the link below by Tony.. > >>>> http://www.mail-archive.com/linux-omap@xxxxxxxxxxxxxxx/msg85932.html > >>>> > >>>> Fix this by passing static parent pointers to the common clock core > >>>> while registering clocks. > >>> > >>> I wonder if we could easily fix this by initializing only some of the > >>> clocks that early? > >> > >> We actually don't need any clocks that early (I mean even before slab init) > >> We only need them before timer init. > > > > Yes and only the timer clocks at that point. The others could be initialized > > later on so we get console error messages without having to turn on DEBUG_LL > > and earlyprintk. > > but that wouldn't be possible with the hwmod dependency on clocks. We would > need to move the hwmod inits further down too. > > > > >> This isn't something specific to OMAP so I started looking at what others > >> in drivers/clk seem to do. > >> > >> I found imx, spear, mvebu all do their clk inits within .init_time callbacks. > >> tegra seems to even do it within .init_irq callback. > >> > >> Either one would work for us too :) > > > > Well I suggest init_irq as that's when we need the first clocks for timer. > > For which platforms? I instead see them being needed only by init_timer, so > was thinking thats a better place instead. > > For the -rc fix to fix the crash with DEBUG_SLAB, is it fine if I move *all* > clock inits down to init_timer (or init_irq). Sounds good to me for the -rc series. How about initialize omap_clk_init() function pointer in the SoC specific omap*_init_early() then just call omap_clk_init() in timer_init? > Splitting clocks alone would not work for now, without hwmod being moved down also. Good point. For the -rc series the sounds like your suggestion is the least intrusive fix and also gets us started removing few more early boot time dependencies. 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
