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/*
* CPU idle driver for Tegra CPUs
*
* Copyright (c) 2010-2012, NVIDIA Corporation.
* Copyright (c) 2011 Google, Inc.
* Author: Colin Cross <ccross@android.com>
* Gary King <gking@nvidia.com>
*
* Rework for 3.3 by Peter De Schrijver <pdeschrijver@nvidia.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*/
#include <linux/clk/tegra.h>
#include <linux/tick.h>
#include <linux/cpuidle.h>
#include <linux/cpu_pm.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <asm/cpuidle.h>
#include <asm/smp_plat.h>
#include <asm/suspend.h>
#include "flowctrl.h"
#include "iomap.h"
#include "irq.h"
#include "pm.h"
#include "reset.h"
#include "sleep.h"
#ifdef CONFIG_PM_SLEEP
static bool abort_flag;
static atomic_t abort_barrier;
static int tegra20_idle_lp2_coupled(struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index);
#define TEGRA20_MAX_STATES 2
#else
#define TEGRA20_MAX_STATES 1
#endif
static struct cpuidle_driver tegra_idle_driver = {
.name = "tegra_idle",
.owner = THIS_MODULE,
.states = {
ARM_CPUIDLE_WFI_STATE_PWR(600),
#ifdef CONFIG_PM_SLEEP
{
.enter = tegra20_idle_lp2_coupled,
.exit_latency = 5000,
.target_residency = 10000,
.power_usage = 0,
.flags = CPUIDLE_FLAG_COUPLED,
.name = "powered-down",
.desc = "CPU power gated",
},
#endif
},
.state_count = TEGRA20_MAX_STATES,
.safe_state_index = 0,
};
#ifdef CONFIG_PM_SLEEP
#ifdef CONFIG_SMP
static int tegra20_reset_sleeping_cpu_1(void)
{
int ret = 0;
tegra_pen_lock();
if (readb(tegra20_cpu1_resettable_status) == CPU_RESETTABLE)
tegra20_cpu_shutdown(1);
else
ret = -EINVAL;
tegra_pen_unlock();
return ret;
}
static void tegra20_wake_cpu1_from_reset(void)
{
tegra_pen_lock();
tegra20_cpu_clear_resettable();
/* enable cpu clock on cpu */
tegra_enable_cpu_clock(1);
/* take the CPU out of reset */
tegra_cpu_out_of_reset(1);
/* unhalt the cpu */
flowctrl_write_cpu_halt(1, 0);
tegra_pen_unlock();
}
static int tegra20_reset_cpu_1(void)
{
if (!cpu_online(1) || !tegra20_reset_sleeping_cpu_1())
return 0;
tegra20_wake_cpu1_from_reset();
return -EBUSY;
}
#else
static inline void tegra20_wake_cpu1_from_reset(void)
{
}
static inline int tegra20_reset_cpu_1(void)
{
return 0;
}
#endif
static bool tegra20_cpu_cluster_power_down(struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index)
{
while (tegra20_cpu_is_resettable_soon())
cpu_relax();
if (tegra20_reset_cpu_1() || !tegra_cpu_rail_off_ready())
return false;
tick_broadcast_enter();
tegra_idle_lp2_last();
tick_broadcast_exit();
if (cpu_online(1))
tegra20_wake_cpu1_from_reset();
return true;
}
#ifdef CONFIG_SMP
static bool tegra20_idle_enter_lp2_cpu_1(struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index)
{
tick_broadcast_enter();
cpu_suspend(0, tegra20_sleep_cpu_secondary_finish);
tegra20_cpu_clear_resettable();
tick_broadcast_exit();
return true;
}
#else
static inline bool tegra20_idle_enter_lp2_cpu_1(struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index)
{
return true;
}
#endif
static int tegra20_idle_lp2_coupled(struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index)
{
bool entered_lp2 = false;
if (tegra_pending_sgi())
ACCESS_ONCE(abort_flag) = true;
cpuidle_coupled_parallel_barrier(dev, &abort_barrier);
if (abort_flag) {
cpuidle_coupled_parallel_barrier(dev, &abort_barrier);
abort_flag = false; /* clean flag for next coming */
return -EINTR;
}
local_fiq_disable();
tegra_set_cpu_in_lp2();
cpu_pm_enter();
if (dev->cpu == 0)
entered_lp2 = tegra20_cpu_cluster_power_down(dev, drv, index);
else
entered_lp2 = tegra20_idle_enter_lp2_cpu_1(dev, drv, index);
cpu_pm_exit();
tegra_clear_cpu_in_lp2();
local_fiq_enable();
smp_rmb();
return entered_lp2 ? index : 0;
}
#endif
/*
* Tegra20 HW appears to have a bug such that PCIe device interrupts, whether
* they are legacy IRQs or MSI, are lost when LP2 is enabled. To work around
* this, simply disable LP2 if the PCI driver and DT node are both enabled.
*/
void tegra20_cpuidle_pcie_irqs_in_use(void)
{
pr_info_once(
"Disabling cpuidle LP2 state, since PCIe IRQs are in use\n");
tegra_idle_driver.states[1].disabled = true;
}
int __init tegra20_cpuidle_init(void)
{
return cpuidle_register(&tegra_idle_driver, cpu_possible_mask);
}
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