On 10/08/2012 04:26 AM, Joseph Lo wrote:
> This supports power-gated (LP2) idle on secondary CPUs for Tegra30.
> The secondary CPUs can go into LP2 state independently. When CPU goes
> into LP2 state, it saves it's state and puts itself to flow controlled
> WFI state. After that, it will been power gated.
> diff --git a/arch/arm/mach-tegra/cpuidle-tegra30.c
> b/arch/arm/mach-tegra/cpuidle-tegra30.c
> static struct cpuidle_driver tegra_idle_driver = {
> .name = "tegra_idle",
> .owner = THIS_MODULE,
> .en_core_tk_irqen = 1,
> - .state_count = 1,
> + .state_count = 2,
Doesn't that assignment need to be ifdef'd just like the array entry
setup below:
> .states = {
> [0] = ARM_CPUIDLE_WFI_STATE_PWR(600),
> +#ifdef CONFIG_PM_SLEEP
> + [1] = {
> + .enter = tegra30_idle_lp2,
> + .exit_latency = 2000,
> + .target_residency = 2200,
> + .power_usage = 0,
> + .flags = CPUIDLE_FLAG_TIME_VALID,
> + .name = "LP2",
> + .desc = "CPU power-gate",
> + },
> +#endif
> },
> };
> @@ -41,6 +114,10 @@ int __init tegra30_cpuidle_init(void)
> struct cpuidle_device *dev;
> struct cpuidle_driver *drv = &tegra_idle_driver;
>
> +#ifndef CONFIG_PM_SLEEP
> + drv->state_count = 1; /* support clockgating only */
> +#endif
Oh, I see it's done here. Just fixing the static initialization seems a
lot simpler?
> diff --git a/arch/arm/mach-tegra/pm.c b/arch/arm/mach-tegra/pm.c
> +void __cpuinit tegra_clear_cpu_in_lp2(int cpu)
> +{
> + spin_lock(&tegra_lp2_lock);
> + BUG_ON(!cpumask_test_cpu(cpu, &tegra_in_lp2));
> + cpumask_clear_cpu(cpu, &tegra_in_lp2);
> +
> + /*
> + * Update the IRAM copy used by the reset handler. The IRAM copy
> + * can't use used directly by cpumask_clear_cpu() because it uses
> + * LDREX/STREX which requires the addressed location to be inner
> + * cacheable and sharable which IRAM isn't.
> + */
> + writel(tegra_in_lp2.bits[0], tegra_cpu_lp2_mask);
> + dsb();
Why not /just/ store the data in IRAM, and read/write directly to it,
rather than maintaining an SDRAM-based copy of it?
Then, wouldn't the body of this function be simply:
spin_lock();
BUG_ON(!(tegra_cpu_lp2_mask & BIT(cpu)));
tegra_cpu_lp2_mask |= BIT(cpu);
spin_unlock();
> +bool __cpuinit tegra_set_cpu_in_lp2(int cpu)
Similar comment here.
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