ARM: tegra30: cpuidle: add powered-down state for secondary CPUs

This supports power-gated idle on secondary CPUs for Tegra30. The
secondary CPUs can go into powered-down state independently. When
CPU goes into this state, it saves it's contexts and puts itself
to flow controlled WFI state. After that, it will been power gated.

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".

Based on the work by:
Scott Williams <scwilliams@nvidia.com>

Signed-off-by: Joseph Lo <josephl@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
This commit is contained in:
Joseph Lo 2012-10-31 17:41:17 +08:00 committed by Stephen Warren
parent d3f293656c
commit d457ef358f
8 changed files with 253 additions and 0 deletions

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@ -8,6 +8,7 @@ obj-y += pmc.o
obj-y += flowctrl.o
obj-y += powergate.o
obj-y += apbio.o
obj-y += pm.o
obj-$(CONFIG_CPU_IDLE) += cpuidle.o
obj-$(CONFIG_CPU_IDLE) += sleep.o
obj-$(CONFIG_ARCH_TEGRA_2x_SOC) += tegra20_clocks.o

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@ -22,21 +22,107 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/cpuidle.h>
#include <linux/cpu_pm.h>
#include <linux/clockchips.h>
#include <asm/cpuidle.h>
#include <asm/proc-fns.h>
#include <asm/suspend.h>
#include <asm/smp_plat.h>
#include "pm.h"
#include "sleep.h"
#ifdef CONFIG_PM_SLEEP
static int tegra30_idle_lp2(struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index);
#endif
static struct cpuidle_driver tegra_idle_driver = {
.name = "tegra_idle",
.owner = THIS_MODULE,
.en_core_tk_irqen = 1,
#ifdef CONFIG_PM_SLEEP
.state_count = 2,
#else
.state_count = 1,
#endif
.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 = "powered-down",
.desc = "CPU power gated",
},
#endif
},
};
static DEFINE_PER_CPU(struct cpuidle_device, tegra_idle_device);
#ifdef CONFIG_PM_SLEEP
#ifdef CONFIG_SMP
static bool tegra30_cpu_core_power_down(struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index)
{
clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &dev->cpu);
smp_wmb();
save_cpu_arch_register();
cpu_suspend(0, tegra30_sleep_cpu_secondary_finish);
restore_cpu_arch_register();
clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &dev->cpu);
return true;
}
#else
static inline bool tegra30_cpu_core_power_down(struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index)
{
return true;
}
#endif
static int __cpuinit tegra30_idle_lp2(struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index)
{
u32 cpu = is_smp() ? cpu_logical_map(dev->cpu) : dev->cpu;
bool entered_lp2 = false;
local_fiq_disable();
tegra_set_cpu_in_lp2(cpu);
cpu_pm_enter();
if (cpu == 0)
cpu_do_idle();
else
entered_lp2 = tegra30_cpu_core_power_down(dev, drv, index);
cpu_pm_exit();
tegra_clear_cpu_in_lp2(cpu);
local_fiq_enable();
smp_rmb();
return (entered_lp2) ? index : 0;
}
#endif
int __init tegra30_cpuidle_init(void)
{
int ret;

74
arch/arm/mach-tegra/pm.c Normal file
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@ -0,0 +1,74 @@
/*
* CPU complex suspend & resume functions for Tegra SoCs
*
* Copyright (c) 2009-2012, NVIDIA Corporation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/io.h>
#include <linux/cpumask.h>
#include "iomap.h"
#include "reset.h"
#ifdef CONFIG_PM_SLEEP
static unsigned int g_diag_reg;
static DEFINE_SPINLOCK(tegra_lp2_lock);
void save_cpu_arch_register(void)
{
/* read diagnostic register */
asm("mrc p15, 0, %0, c15, c0, 1" : "=r"(g_diag_reg) : : "cc");
return;
}
void restore_cpu_arch_register(void)
{
/* write diagnostic register */
asm("mcr p15, 0, %0, c15, c0, 1" : : "r"(g_diag_reg) : "cc");
return;
}
void __cpuinit tegra_clear_cpu_in_lp2(int phy_cpu_id)
{
u32 *cpu_in_lp2 = tegra_cpu_lp2_mask;
spin_lock(&tegra_lp2_lock);
BUG_ON(!(*cpu_in_lp2 & BIT(phy_cpu_id)));
*cpu_in_lp2 &= ~BIT(phy_cpu_id);
spin_unlock(&tegra_lp2_lock);
}
bool __cpuinit tegra_set_cpu_in_lp2(int phy_cpu_id)
{
bool last_cpu = false;
cpumask_t *cpu_lp2_mask = tegra_cpu_lp2_mask;
u32 *cpu_in_lp2 = tegra_cpu_lp2_mask;
spin_lock(&tegra_lp2_lock);
BUG_ON((*cpu_in_lp2 & BIT(phy_cpu_id)));
*cpu_in_lp2 |= BIT(phy_cpu_id);
if ((phy_cpu_id == 0) && cpumask_equal(cpu_lp2_mask, cpu_online_mask))
last_cpu = true;
spin_unlock(&tegra_lp2_lock);
return last_cpu;
}
#endif

30
arch/arm/mach-tegra/pm.h Normal file
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@ -0,0 +1,30 @@
/*
* Copyright (C) 2010 Google, Inc.
* Copyright (c) 2010-2012 NVIDIA Corporation. All rights reserved.
*
* Author:
* Colin Cross <ccross@google.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _MACH_TEGRA_PM_H_
#define _MACH_TEGRA_PM_H_
void save_cpu_arch_register(void);
void restore_cpu_arch_register(void);
void tegra_clear_cpu_in_lp2(int phy_cpu_id);
bool tegra_set_cpu_in_lp2(int phy_cpu_id);
#endif /* _MACH_TEGRA_PM_H_ */

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@ -29,6 +29,8 @@
#ifndef __ASSEMBLY__
#include "irammap.h"
extern unsigned long __tegra_cpu_reset_handler_data[TEGRA_RESET_DATA_SIZE];
void __tegra_cpu_reset_handler_start(void);
@ -36,6 +38,13 @@ void __tegra_cpu_reset_handler(void);
void __tegra_cpu_reset_handler_end(void);
void tegra_secondary_startup(void);
#ifdef CONFIG_PM_SLEEP
#define tegra_cpu_lp2_mask \
(IO_ADDRESS(TEGRA_IRAM_BASE + TEGRA_IRAM_RESET_HANDLER_OFFSET + \
((u32)&__tegra_cpu_reset_handler_data[TEGRA_RESET_MASK_LP2] - \
(u32)__tegra_cpu_reset_handler_start)))
#endif
#define tegra_cpu_reset_handler_offset \
((u32)__tegra_cpu_reset_handler - \
(u32)__tegra_cpu_reset_handler_start)

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@ -17,6 +17,7 @@
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/asm-offsets.h>
#include "sleep.h"
#include "flowctrl.h"
@ -80,6 +81,7 @@ delay_1:
ldr r3, [r1] @ read CSR
str r3, [r1] @ clear CSR
tst r0, #TEGRA30_POWER_HOTPLUG_SHUTDOWN
moveq r3, #FLOW_CTRL_WAIT_FOR_INTERRUPT @ For LP2
movne r3, #FLOW_CTRL_WAITEVENT @ For hotplug
str r3, [r2]
ldr r0, [r2]
@ -103,3 +105,23 @@ wfe_war:
ENDPROC(tegra30_cpu_shutdown)
#endif
#ifdef CONFIG_PM_SLEEP
/*
* tegra30_sleep_cpu_secondary_finish(unsigned long v2p)
*
* Enters LP2 on secondary CPU by exiting coherency and powergating the CPU.
*/
ENTRY(tegra30_sleep_cpu_secondary_finish)
mov r7, lr
/* Flush and disable the L1 data cache */
bl tegra_disable_clean_inv_dcache
/* Powergate this CPU. */
mov r0, #0 @ power mode flags (!hotplug)
bl tegra30_cpu_shutdown
mov r0, #1 @ never return here
mov pc, r7
ENDPROC(tegra30_sleep_cpu_secondary_finish)
#endif

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@ -25,9 +25,38 @@
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/cp15.h>
#include "iomap.h"
#include "flowctrl.h"
#include "sleep.h"
#ifdef CONFIG_PM_SLEEP
/*
* tegra_disable_clean_inv_dcache
*
* disable, clean & invalidate the D-cache
*
* Corrupted registers: r1-r3, r6, r8, r9-r11
*/
ENTRY(tegra_disable_clean_inv_dcache)
stmfd sp!, {r0, r4-r5, r7, r9-r11, lr}
dmb @ ensure ordering
/* Disable the D-cache */
mrc p15, 0, r2, c1, c0, 0
bic r2, r2, #CR_C
mcr p15, 0, r2, c1, c0, 0
isb
/* Flush the D-cache */
bl v7_flush_dcache_louis
/* Trun off coherency */
exit_smp r4, r5
ldmfd sp!, {r0, r4-r5, r7, r9-r11, pc}
ENDPROC(tegra_disable_clean_inv_dcache)
#endif

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@ -82,5 +82,7 @@ static inline void tegra20_hotplug_init(void) {}
static inline void tegra30_hotplug_init(void) {}
#endif
int tegra30_sleep_cpu_secondary_finish(unsigned long);
#endif
#endif