| Message ID | 1404920715-19834-2-git-send-email-thomas.petazzoni@free-electrons.com (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
On Wed, Jul 09, 2014 at 05:45:09PM +0200, Thomas Petazzoni wrote: > In the Armada XP SMP support code, we are reading the clock frequency > of the booting CPU, and use that to assign the same frequency to the > other CPUs, and we do this while the clocks are disabled. > > However, the CPU clocks are in fact never prepared/enabled, and to > support cpufreq, we now have two code paths to change the frequency of > the CPU clocks in the CPU clock driver: one when the clock is enabled > (dynamic frequency scaling), one when the clock is disabled (adjusting > the CPU frequency before starting the CPU). In order for this to work, > the CPU clocks now have to be prepared and enabled after the initial > synchronization of the clock frequencies is done, so that all future > rate changes of the CPU clocks will trigger a dynamic frequency > scaling transition. > > Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> > --- > arch/arm/mach-mvebu/platsmp.c | 1 + > 1 file changed, 1 insertion(+) Tentatively applied patches 1-3, and 5 to mvebu/soc-cpufreq to get some coverage in -next. thx, Jason. -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/arm/mach-mvebu/platsmp.c b/arch/arm/mach-mvebu/platsmp.c index 88b976b3..4880b0f 100644 --- a/arch/arm/mach-mvebu/platsmp.c +++ b/arch/arm/mach-mvebu/platsmp.c @@ -67,6 +67,7 @@ static void __init set_secondary_cpus_clock(void) if (!cpu_clk) return; clk_set_rate(cpu_clk, rate); + clk_prepare_enable(cpu_clk); } }
In the Armada XP SMP support code, we are reading the clock frequency of the booting CPU, and use that to assign the same frequency to the other CPUs, and we do this while the clocks are disabled. However, the CPU clocks are in fact never prepared/enabled, and to support cpufreq, we now have two code paths to change the frequency of the CPU clocks in the CPU clock driver: one when the clock is enabled (dynamic frequency scaling), one when the clock is disabled (adjusting the CPU frequency before starting the CPU). In order for this to work, the CPU clocks now have to be prepared and enabled after the initial synchronization of the clock frequencies is done, so that all future rate changes of the CPU clocks will trigger a dynamic frequency scaling transition. Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> --- arch/arm/mach-mvebu/platsmp.c | 1 + 1 file changed, 1 insertion(+)