Commit d552920a authored by Joseph Lo's avatar Joseph Lo Committed by Stephen Warren
Browse files

ARM: tegra30: cpuidle: add powered-down state for CPU0 



This is a power gating idle mode. It support power gating vdd_cpu rail
after all cpu cores in "powered-down" status. For Tegra30, the CPU0 can
enter this state only when all secondary CPU is offline. We need to take
care and make sure whole secondary CPUs were offline and checking the
CPU power gate status. After that, the CPU0 can go into "powered-down"
state safely. Then shut off the CPU rail.

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".

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

Signed-off-by: default avatarJoseph Lo <josephl@nvidia.com>
Signed-off-by: default avatarStephen Warren <swarren@nvidia.com>
parent 01459c69

arch/arm/mach-tegra/cpuidle-tegra30.c

+40 −4
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ 


#include "pm.h"

#include "sleep.h"

#include "tegra_cpu_car.h"



#ifdef CONFIG_PM_SLEEP

static int tegra30_idle_lp2(struct cpuidle_device *dev,
@@ -67,6 +68,31 @@ static struct cpuidle_driver tegra_idle_driver = { 
static DEFINE_PER_CPU(struct cpuidle_device, tegra_idle_device);



#ifdef CONFIG_PM_SLEEP

static bool tegra30_cpu_cluster_power_down(struct cpuidle_device *dev,

					   struct cpuidle_driver *drv,

					   int index)

{

	struct cpuidle_state *state = &drv->states[index];

	u32 cpu_on_time = state->exit_latency;

	u32 cpu_off_time = state->target_residency - state->exit_latency;



	/* All CPUs entering LP2 is not working.

	 * Don't let CPU0 enter LP2 when any secondary CPU is online.

	 */

	if (num_online_cpus() > 1 || !tegra_cpu_rail_off_ready()) {

		cpu_do_idle();

		return false;

	}



	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &dev->cpu);



	tegra_idle_lp2_last(cpu_on_time, cpu_off_time);



	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &dev->cpu);



	return true;

}



#ifdef CONFIG_SMP

static bool tegra30_cpu_core_power_down(struct cpuidle_device *dev,

					struct cpuidle_driver *drv,
@@ -101,16 +127,22 @@ static int __cpuinit tegra30_idle_lp2(struct cpuidle_device *dev, 
{

	u32 cpu = is_smp() ? cpu_logical_map(dev->cpu) : dev->cpu;

	bool entered_lp2 = false;

	bool last_cpu;



	local_fiq_disable();



	tegra_set_cpu_in_lp2(cpu);

	last_cpu = tegra_set_cpu_in_lp2(cpu);

	cpu_pm_enter();



	if (cpu == 0)

		cpu_do_idle();

	if (cpu == 0) {

		if (last_cpu)

			entered_lp2 = tegra30_cpu_cluster_power_down(dev, drv,

								     index);

		else

			cpu_do_idle();

	} else {

		entered_lp2 = tegra30_cpu_core_power_down(dev, drv, index);

	}



	cpu_pm_exit();

	tegra_clear_cpu_in_lp2(cpu);
@@ -130,6 +162,10 @@ int __init tegra30_cpuidle_init(void) 
	struct cpuidle_device *dev;

	struct cpuidle_driver *drv = &tegra_idle_driver;



#ifdef CONFIG_PM_SLEEP

	tegra_tear_down_cpu = tegra30_tear_down_cpu;

#endif



	ret = cpuidle_register_driver(&tegra_idle_driver);

	if (ret) {

		pr_err("CPUidle driver registration failed\n");

arch/arm/mach-tegra/pm.c

+144 −0
Original line number Diff line number Diff line
@@ -20,13 +20,36 @@ 
#include <linux/spinlock.h>

#include <linux/io.h>

#include <linux/cpumask.h>

#include <linux/delay.h>

#include <linux/cpu_pm.h>

#include <linux/clk.h>

#include <linux/err.h>



#include <asm/smp_plat.h>

#include <asm/cacheflush.h>

#include <asm/suspend.h>

#include <asm/idmap.h>

#include <asm/proc-fns.h>

#include <asm/tlbflush.h>



#include "iomap.h"

#include "reset.h"

#include "flowctrl.h"

#include "sleep.h"

#include "tegra_cpu_car.h"



#define TEGRA_POWER_CPU_PWRREQ_OE	(1 << 16)  /* CPU pwr req enable */



#define PMC_CTRL		0x0

#define PMC_CPUPWRGOOD_TIMER	0xc8

#define PMC_CPUPWROFF_TIMER	0xcc



#ifdef CONFIG_PM_SLEEP

static unsigned int g_diag_reg;

static DEFINE_SPINLOCK(tegra_lp2_lock);

static void __iomem *pmc = IO_ADDRESS(TEGRA_PMC_BASE);

static struct clk *tegra_pclk;

void (*tegra_tear_down_cpu)(void);



void save_cpu_arch_register(void)

{
@@ -42,6 +65,89 @@ void restore_cpu_arch_register(void) 
	return;

}



static void set_power_timers(unsigned long us_on, unsigned long us_off)

{

	unsigned long long ticks;

	unsigned long long pclk;

	unsigned long rate;

	static unsigned long tegra_last_pclk;



	if (tegra_pclk == NULL) {

		tegra_pclk = clk_get_sys(NULL, "pclk");

		WARN_ON(IS_ERR(tegra_pclk));

	}



	rate = clk_get_rate(tegra_pclk);



	if (WARN_ON_ONCE(rate <= 0))

		pclk = 100000000;

	else

		pclk = rate;



	if ((rate != tegra_last_pclk)) {

		ticks = (us_on * pclk) + 999999ull;

		do_div(ticks, 1000000);

		writel((unsigned long)ticks, pmc + PMC_CPUPWRGOOD_TIMER);



		ticks = (us_off * pclk) + 999999ull;

		do_div(ticks, 1000000);

		writel((unsigned long)ticks, pmc + PMC_CPUPWROFF_TIMER);

		wmb();

	}

	tegra_last_pclk = pclk;

}



/*

 * restore_cpu_complex

 *

 * restores cpu clock setting, clears flow controller

 *

 * Always called on CPU 0.

 */

static void restore_cpu_complex(void)

{

	int cpu = smp_processor_id();



	BUG_ON(cpu != 0);



#ifdef CONFIG_SMP

	cpu = cpu_logical_map(cpu);

#endif



	/* Restore the CPU clock settings */

	tegra_cpu_clock_resume();



	flowctrl_cpu_suspend_exit(cpu);



	restore_cpu_arch_register();

}



/*

 * suspend_cpu_complex

 *

 * saves pll state for use by restart_plls, prepares flow controller for

 * transition to suspend state

 *

 * Must always be called on cpu 0.

 */

static void suspend_cpu_complex(void)

{

	int cpu = smp_processor_id();



	BUG_ON(cpu != 0);



#ifdef CONFIG_SMP

	cpu = cpu_logical_map(cpu);

#endif



	/* Save the CPU clock settings */

	tegra_cpu_clock_suspend();



	flowctrl_cpu_suspend_enter(cpu);



	save_cpu_arch_register();

}



void __cpuinit tegra_clear_cpu_in_lp2(int phy_cpu_id)

{

	u32 *cpu_in_lp2 = tegra_cpu_lp2_mask;
@@ -71,4 +177,42 @@ bool __cpuinit tegra_set_cpu_in_lp2(int phy_cpu_id) 
	spin_unlock(&tegra_lp2_lock);

	return last_cpu;

}



static int tegra_sleep_cpu(unsigned long v2p)

{

	/* Switch to the identity mapping. */

	cpu_switch_mm(idmap_pgd, &init_mm);



	/* Flush the TLB. */

	local_flush_tlb_all();



	tegra_sleep_cpu_finish(v2p);



	/* should never here */

	BUG();



	return 0;

}



void tegra_idle_lp2_last(u32 cpu_on_time, u32 cpu_off_time)

{

	u32 mode;



	/* Only the last cpu down does the final suspend steps */

	mode = readl(pmc + PMC_CTRL);

	mode |= TEGRA_POWER_CPU_PWRREQ_OE;

	writel(mode, pmc + PMC_CTRL);



	set_power_timers(cpu_on_time, cpu_off_time);



	cpu_cluster_pm_enter();

	suspend_cpu_complex();

	outer_disable();



	cpu_suspend(PHYS_OFFSET - PAGE_OFFSET, &tegra_sleep_cpu);



	outer_resume();

	restore_cpu_complex();

	cpu_cluster_pm_exit();

}

#endif

arch/arm/mach-tegra/pm.h

+3 −0
Original line number Diff line number Diff line
@@ -27,4 +27,7 @@ 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);



void tegra_idle_lp2_last(u32 cpu_on_time, u32 cpu_off_time);

extern void (*tegra_tear_down_cpu)(void);



#endif /* _MACH_TEGRA_PM_H_ */

arch/arm/mach-tegra/sleep-tegra30.S

+44 −0
Original line number Diff line number Diff line
@@ -124,4 +124,48 @@ ENTRY(tegra30_sleep_cpu_secondary_finish) 
	mov	r0, #1                          @ never return here

	mov	pc, r7

ENDPROC(tegra30_sleep_cpu_secondary_finish)



/*

 * tegra30_tear_down_cpu

 *

 * Switches the CPU to enter sleep.

 */

ENTRY(tegra30_tear_down_cpu)

	mov32	r6, TEGRA_FLOW_CTRL_BASE



	b	tegra30_enter_sleep

ENDPROC(tegra30_tear_down_cpu)



/*

 * tegra30_enter_sleep

 *

 * uses flow controller to enter sleep state

 * executes from IRAM with SDRAM in selfrefresh when target state is LP0 or LP1

 * executes from SDRAM with target state is LP2

 * r6 = TEGRA_FLOW_CTRL_BASE

 */

tegra30_enter_sleep:

	cpu_id	r1



	cpu_to_csr_reg	r2, r1

	ldr	r0, [r6, r2]

	orr	r0, r0, #FLOW_CTRL_CSR_INTR_FLAG | FLOW_CTRL_CSR_EVENT_FLAG

	orr	r0, r0, #FLOW_CTRL_CSR_ENABLE

	str	r0, [r6, r2]



	mov	r0, #FLOW_CTRL_WAIT_FOR_INTERRUPT

	orr	r0, r0, #FLOW_CTRL_HALT_CPU_IRQ | FLOW_CTRL_HALT_CPU_FIQ

	cpu_to_halt_reg r2, r1

	str	r0, [r6, r2]

	dsb

	ldr	r0, [r6, r2] /* memory barrier */



halted:

	isb

	dsb

	wfi	/* CPU should be power gated here */



	/* !!!FIXME!!! Implement halt failure handler */

	b	halted



#endif

arch/arm/mach-tegra/sleep.S

+42 −0
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 
#include <linux/linkage.h>



#include <asm/assembler.h>

#include <asm/cache.h>

#include <asm/cp15.h>



#include "iomap.h"
@@ -59,4 +60,45 @@ ENTRY(tegra_disable_clean_inv_dcache) 
	ldmfd	sp!, {r0, r4-r5, r7, r9-r11, pc}

ENDPROC(tegra_disable_clean_inv_dcache)



/*

 * tegra_sleep_cpu_finish(unsigned long v2p)

 *

 * enters suspend in LP2 by turning off the mmu and jumping to

 * tegra?_tear_down_cpu

 */

ENTRY(tegra_sleep_cpu_finish)

	/* Flush and disable the L1 data cache */

	bl	tegra_disable_clean_inv_dcache



	mov32	r6, tegra_tear_down_cpu

	ldr	r1, [r6]

	add	r1, r1, r0



	mov32	r3, tegra_shut_off_mmu

	add	r3, r3, r0

	mov	r0, r1



	mov	pc, r3

ENDPROC(tegra_sleep_cpu_finish)



/*

 * tegra_shut_off_mmu

 *

 * r0 = physical address to jump to with mmu off

 *

 * called with VA=PA mapping

 * turns off MMU, icache, dcache and branch prediction

 */

	.align	L1_CACHE_SHIFT

	.pushsection	.idmap.text, "ax"

ENTRY(tegra_shut_off_mmu)

	mrc	p15, 0, r3, c1, c0, 0

	movw	r2, #CR_I | CR_Z | CR_C | CR_M

	bic	r3, r3, r2

	dsb

	mcr	p15, 0, r3, c1, c0, 0

	isb

	mov	pc, r0

ENDPROC(tegra_shut_off_mmu)

	.popsection

#endif

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