On Wed, 18 Jun 2014, Abhilash Kesavan wrote:
> Turning off a cluster when all 4 cores of the cluster are powered off
> saves power significantly. Powering off the A15 L2 alone gives around
> 100mW in savings. Add support for powering off the A15/A7 clusters on
> exynos5420/5800.
>
> The patch enables specific register bits which ensure that:
> - cluster L2 will be turned on before the first man is powered up.
> - last man will be turned off before the cluster L2 is turned off.
> - core is powered down before powering it up.
>
> Remove the exynos_cluster_power_control function completely as we can
> rely on the above mentioned bits rather than polling the cluster power
> status register.
>
> Signed-off-by: Abhilash Kesavan <a.kesavan@xxxxxxxxxxx>
Minor nit below:
> @@ -342,6 +318,26 @@ static int __init exynos_mcpm_init(void)
> pr_info("Exynos MCPM support installed\n");
>
> /*
> + * On Exynos5420/5800 for the A15 and A7 clusters:
> + *
> + * EXYNOS5420_ENABLE_AUTOMATIC_CORE_DOWN ensures that all the cores
> + * in a cluster are turned off before turning off the cluster L2.
> + *
> + * EXYNOS5420_USE_ARM_CORE_DOWN_STATE ensures that a cores is powered
> + * off before waking it up.
> + *
> + * EXYNOS5420_USE_L2_COMMON_UP_STATE ensures that cluster L2 will be
> + * turned on before the first man is powered up.
> + */
> + for (i = 0; i < EXYNOS5420_NR_CLUSTERS; i++) {
> + value = __raw_readl(EXYNOS_COMMON_CONFIGURATION(i) + 0x8);
> + value |= EXYNOS5420_ENABLE_AUTOMATIC_CORE_DOWN |
> + EXYNOS5420_USE_ARM_CORE_DOWN_STATE |
> + EXYNOS5420_USE_L2_COMMON_UP_STATE;
> + __raw_writel(value, EXYNOS_COMMON_CONFIGURATION(i) + 0x8);
Surely you can add another define in mach-exynos/regs-pmu.h to better
identify this register instead of EXYNOS_COMMON_CONFIGURATION()+8 ?
After that, you may add:
Acked-by: Nicolas Pitre <nico@xxxxxxxxxx>
Nicolas
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