On 08/20/2013 02:44 PM, Arnd Bergmann wrote: > On Tuesday 20 August 2013, Stephen Warren wrote: >> On 08/19/2013 08:04 PM, Sebastian Hesselbarth wrote: >>> Most DT ARM machs require common clock providers initialized before timers. >>> Currently, arch/arm machs use .init_time to call clk_of_init right before >>> clocksource_of_init. This prevents to remove that hook and use the default >>> hook instead. clk_of_init now checks for multiple calls to it, so add >>> the call to ARM arch time_init by default. >> >> Some SoCs call this function in .init_irq() rather than .init_time(). >> Perhaps we adjust this patch to do that instead. That way, we can >> presumably get rid of patch 1/17 since we can eliminate any duplicate >> calls, and adjust patch 14/17 (Tegra board file) to remove its custom >> call to of_clock_init(NULL)? > > I think we should do thinks as late as possible in general. We probably > need clocks running on most platforms before we can set up timers, so > it makes sense to do the clocks first, but very few platforms require > clocks to be running before the interrupt controller is set up. > > A nicer solution would be to change the tegra code to not require this > to be called this early, if at all possible.
Hmm. This probably isn't too hard. I /think/ the only reason the clocks are initialized early is: * The PMC HW block is involved in the path of some interrupts (i.e. it inverts, or not, the IRQ input pin dedicated to the PMIC). * So, that part of the PMC must be initialized early so that the IRQ polarity is correct. * The PMC initialization is currently monolithic, and the PMC has some clock inputs, so the init routine ends up calling of_clk_get_by_name(), and hence clocks must be set up early too. Perhaps if we just separate tegra_pmc_init() into two functions which initialize different parts of the PMC, we can get rid of the tegra_dt_init_irq() -> tegra_pmc_init() -> of_clk_get_by_name() call path, and hence move Tegra's call to of_clk_init() to the typical place. I'll try it. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
