From: swarren@wwwdotorg•org (Stephen Warren)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH V3 2/5] ARM: tegra20: cpuidle: add powered-down state for secondary CPU
Date: Thu, 20 Dec 2012 10:43:04 -0700 [thread overview]
Message-ID: <50D34E28.5000208@wwwdotorg.org> (raw)
In-Reply-To: <1355797861-12759-3-git-send-email-josephl@nvidia.com>
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".
> 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.
> diff --git a/arch/arm/mach-tegra/pm.c b/arch/arm/mach-tegra/pm.c
> @@ -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)
next prev parent reply other threads:[~2012-12-20 17:43 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-18 2:30 [PATCH V3 0/5] ARM: tegra20: cpuidle: add power-down state Joseph Lo
2012-12-18 2:30 ` [PATCH V3 1/5] ARM: tegra: add pending SGI checking API Joseph Lo
2012-12-18 2:42 ` Colin Cross
2012-12-18 2:57 ` Joseph Lo
2012-12-18 10:15 ` Peter De Schrijver
2012-12-18 19:36 ` Colin Cross
2012-12-19 1:06 ` Joseph Lo
2012-12-19 3:47 ` Joseph Lo
2012-12-20 7:16 ` Santosh Shilimkar
2012-12-20 9:34 ` Peter De Schrijver
2012-12-20 9:49 ` Santosh Shilimkar
2012-12-20 9:59 ` Peter De Schrijver
2012-12-20 10:24 ` Santosh Shilimkar
2012-12-20 11:14 ` Peter De Schrijver
2012-12-20 12:06 ` Santosh Shilimkar
2012-12-18 2:30 ` [PATCH V3 2/5] ARM: tegra20: cpuidle: add powered-down state for secondary CPU Joseph Lo
2012-12-18 2:46 ` Colin Cross
2012-12-18 3:06 ` Joseph Lo
2012-12-20 17:43 ` Stephen Warren [this message]
2012-12-21 6:36 ` Joseph Lo
2012-12-21 21:04 ` Stephen Warren
2012-12-18 2:30 ` [PATCH V3 3/5] ARM: tegra20: clocks: add CPU low-power function into tegra_cpu_car_ops Joseph Lo
2012-12-20 17:46 ` Stephen Warren
2012-12-21 5:02 ` Joseph Lo
2012-12-21 21:10 ` Stephen Warren
2012-12-18 2:31 ` [PATCH V3 4/5] ARM: tegra20: flowctrl: add support for cpu_suspend_enter/exit Joseph Lo
2012-12-18 2:31 ` [PATCH V3 5/5] ARM: tegra20: cpuidle: apply coupled cpuidle for powered-down mode Joseph Lo
2012-12-18 10:18 ` Peter De Schrijver
2012-12-20 17:54 ` Stephen Warren
2012-12-21 7:10 ` Joseph Lo
2012-12-21 21:06 ` Stephen Warren
2013-01-02 19:05 ` [PATCH V3 0/5] ARM: tegra20: cpuidle: add power-down state Stephen Warren
2013-01-03 8:39 ` Joseph Lo
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