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![Mark Rutland](/assets/img/avatar_default.png)
Please do not apply this to mainline directly, instead please re-run the coccinelle script shown below and apply its output. For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't harmful, and changing them results in churn. However, for some features, the read/write distinction is critical to correct operation. To distinguish these cases, separate read/write accessors must be used. This patch migrates (most) remaining ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following coccinelle script: ---- // Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and // WRITE_ONCE() // $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
228 lines
4.8 KiB
C
228 lines
4.8 KiB
C
/*
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* CPU idle driver for Tegra CPUs
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*
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* Copyright (c) 2010-2012, NVIDIA Corporation.
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* Copyright (c) 2011 Google, Inc.
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* Author: Colin Cross <ccross@android.com>
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* Gary King <gking@nvidia.com>
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*
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* Rework for 3.3 by Peter De Schrijver <pdeschrijver@nvidia.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*/
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#include <linux/clk/tegra.h>
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#include <linux/tick.h>
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#include <linux/cpuidle.h>
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#include <linux/cpu_pm.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <soc/tegra/flowctrl.h>
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#include <asm/cpuidle.h>
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#include <asm/smp_plat.h>
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#include <asm/suspend.h>
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#include "cpuidle.h"
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#include "iomap.h"
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#include "irq.h"
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#include "pm.h"
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#include "reset.h"
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#include "sleep.h"
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#ifdef CONFIG_PM_SLEEP
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static bool abort_flag;
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static atomic_t abort_barrier;
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static int tegra20_idle_lp2_coupled(struct cpuidle_device *dev,
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struct cpuidle_driver *drv,
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int index);
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#define TEGRA20_MAX_STATES 2
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#else
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#define TEGRA20_MAX_STATES 1
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#endif
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static struct cpuidle_driver tegra_idle_driver = {
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.name = "tegra_idle",
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.owner = THIS_MODULE,
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.states = {
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ARM_CPUIDLE_WFI_STATE_PWR(600),
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#ifdef CONFIG_PM_SLEEP
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{
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.enter = tegra20_idle_lp2_coupled,
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.exit_latency = 5000,
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.target_residency = 10000,
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.power_usage = 0,
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.flags = CPUIDLE_FLAG_COUPLED,
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.name = "powered-down",
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.desc = "CPU power gated",
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},
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#endif
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},
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.state_count = TEGRA20_MAX_STATES,
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.safe_state_index = 0,
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};
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#ifdef CONFIG_PM_SLEEP
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#ifdef CONFIG_SMP
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static int tegra20_reset_sleeping_cpu_1(void)
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{
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int ret = 0;
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tegra_pen_lock();
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if (readb(tegra20_cpu1_resettable_status) == CPU_RESETTABLE)
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tegra20_cpu_shutdown(1);
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else
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ret = -EINVAL;
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tegra_pen_unlock();
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return ret;
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}
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static void tegra20_wake_cpu1_from_reset(void)
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{
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tegra_pen_lock();
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tegra20_cpu_clear_resettable();
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/* enable cpu clock on cpu */
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tegra_enable_cpu_clock(1);
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/* take the CPU out of reset */
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tegra_cpu_out_of_reset(1);
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/* unhalt the cpu */
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flowctrl_write_cpu_halt(1, 0);
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tegra_pen_unlock();
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}
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static int tegra20_reset_cpu_1(void)
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{
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if (!cpu_online(1) || !tegra20_reset_sleeping_cpu_1())
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return 0;
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tegra20_wake_cpu1_from_reset();
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return -EBUSY;
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}
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#else
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static inline void tegra20_wake_cpu1_from_reset(void)
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{
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}
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static inline int tegra20_reset_cpu_1(void)
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{
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return 0;
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}
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#endif
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static bool tegra20_cpu_cluster_power_down(struct cpuidle_device *dev,
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struct cpuidle_driver *drv,
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int index)
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{
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while (tegra20_cpu_is_resettable_soon())
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cpu_relax();
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if (tegra20_reset_cpu_1() || !tegra_cpu_rail_off_ready())
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return false;
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tick_broadcast_enter();
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tegra_idle_lp2_last();
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tick_broadcast_exit();
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if (cpu_online(1))
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tegra20_wake_cpu1_from_reset();
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return true;
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}
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#ifdef CONFIG_SMP
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static bool tegra20_idle_enter_lp2_cpu_1(struct cpuidle_device *dev,
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struct cpuidle_driver *drv,
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int index)
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{
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tick_broadcast_enter();
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cpu_suspend(0, tegra20_sleep_cpu_secondary_finish);
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tegra20_cpu_clear_resettable();
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tick_broadcast_exit();
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return true;
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}
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#else
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static inline bool tegra20_idle_enter_lp2_cpu_1(struct cpuidle_device *dev,
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struct cpuidle_driver *drv,
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int index)
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{
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return true;
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}
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#endif
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static int tegra20_idle_lp2_coupled(struct cpuidle_device *dev,
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struct cpuidle_driver *drv,
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int index)
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{
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bool entered_lp2 = false;
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if (tegra_pending_sgi())
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WRITE_ONCE(abort_flag, true);
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cpuidle_coupled_parallel_barrier(dev, &abort_barrier);
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if (abort_flag) {
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cpuidle_coupled_parallel_barrier(dev, &abort_barrier);
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abort_flag = false; /* clean flag for next coming */
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return -EINTR;
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}
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local_fiq_disable();
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tegra_set_cpu_in_lp2();
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cpu_pm_enter();
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if (dev->cpu == 0)
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entered_lp2 = tegra20_cpu_cluster_power_down(dev, drv, index);
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else
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entered_lp2 = tegra20_idle_enter_lp2_cpu_1(dev, drv, index);
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cpu_pm_exit();
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tegra_clear_cpu_in_lp2();
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local_fiq_enable();
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smp_rmb();
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return entered_lp2 ? index : 0;
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}
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#endif
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/*
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* Tegra20 HW appears to have a bug such that PCIe device interrupts, whether
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* they are legacy IRQs or MSI, are lost when LP2 is enabled. To work around
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* this, simply disable LP2 if the PCI driver and DT node are both enabled.
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*/
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void tegra20_cpuidle_pcie_irqs_in_use(void)
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{
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pr_info_once(
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"Disabling cpuidle LP2 state, since PCIe IRQs are in use\n");
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tegra_idle_driver.states[1].disabled = true;
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}
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int __init tegra20_cpuidle_init(void)
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{
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return cpuidle_register(&tegra_idle_driver, cpu_possible_mask);
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}
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