[PATCH V3 2/5] ARM: tegra20: cpuidle: add powered-down state for secondary CPU
From: Stephen Warren <hidden>
Date: 2012-12-20 17:43:04
Also in:
linux-tegra
On 12/17/2012 07:30 PM, Joseph Lo wrote:
The powered-down state of Tegra20 requires power gating both CPU cores. When the secondary CPU requests to enter powered-down state, it saves its own contexts and then enters WFI. The Tegra20 had a limition to power down both CPU cores. The secondary CPU must waits for CPU0 in powered-down state too. If the secondary CPU be woken up before CPU0 entering powered-down state, then it needs to restore its CPU states and waits for next chance. Be aware of that, you may see the legacy power state "LP2" in the code which is exactly the same meaning of "CPU power down".
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diff --git a/arch/arm/mach-tegra/cpuidle-tegra20.c b/arch/arm/mach-tegra/cpuidle-tegra20.c
int __init tegra20_cpuidle_init(void)
+ drv->state_count = sizeof(tegra_idle_states) / + sizeof(struct cpuidle_state);
Use ARRAY_SIZE() there?
+ for (i = 0; i < drv->state_count; i++) + memcpy(&drv->states[i], &tegra_idle_states[i], + sizeof(struct cpuidle_state));
Can't you call memcpy() once: memcpy(drv->states, tegra_idle_states, drv->state_count * sizeof(drv->states[0])); ... although I personally much preferred when all this was just static initialization directly in tegra_idle_driver, rather than all this messy copying. Really, struct cpuidle_driver should point at the array, rather than including it.
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diff --git a/arch/arm/mach-tegra/pm.c b/arch/arm/mach-tegra/pm.c
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@@ -173,6 +173,8 @@ bool __cpuinit tegra_set_cpu_in_lp2(int phy_cpu_id) if ((phy_cpu_id == 0) && cpumask_equal(cpu_lp2_mask, cpu_online_mask)) last_cpu = true; + else if (phy_cpu_id == 1) + tegra20_cpu_set_resettable_soon(); spin_unlock(&tegra_lp2_lock); return last_cpu;
Shouldn't the code in that else branch have a run-time check for whether it's running on Tegra20? When compiled without Tegra20 support, tegra20_cpu_set_resettable_soon() is a dummy static inline, but when both Tegra20 and Tegra30 are compiled in, isn't that code going to run when it shouldn't; pm.c being a common file. (Peter again, can you please review/ack this series. Thanks)