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linux/arch/arm/mach-omap2/omap-mpuss-lowpower.c
Nishanth Menon a30d81b98a ARM: OMAP4+: PM: Program CPU logic power state 
CPU logic power state is never programmed in either the initialization
or the suspend/resume logic, instead, we depend on mpuss to program this
properly. However, this leaves CPU logic power state indeterminate and
most probably in reset configuration (If bootloader or other similar
software have'nt monkeyed with the register). This can make powerstate=
RET be either programmed for CSWR (logic=ret) or OSWR(logic = OFF) and
in OSWR, there can be context loss when the code does not expect it.

To prevent all these confusions, just support clearly ON, INA, CSWR,
OFF which is the intent of the existing code by explicitly programming
logic state.

NOTE: since this is a hot path (using in cpuidle), the exit path just
programs powerstate (logic state is immaterial when powerstate is ON).

Without doing this, we end up with lockups when CPUs enter OSWR and
multiple blocks loose context, when we expect them to hit CSWR.

Signed-off-by: Nishanth Menon <nm@ti.com>
Acked-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
2014-11-10 16:02:05 -08:00

447 lines
12 KiB
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/*
* OMAP MPUSS low power code
*
* Copyright (C) 2011 Texas Instruments, Inc.
* Santosh Shilimkar <santosh.shilimkar@ti.com>
*
* OMAP4430 MPUSS mainly consists of dual Cortex-A9 with per-CPU
* Local timer and Watchdog, GIC, SCU, PL310 L2 cache controller,
* CPU0 and CPU1 LPRM modules.
* CPU0, CPU1 and MPUSS each have there own power domain and
* hence multiple low power combinations of MPUSS are possible.
*
* The CPU0 and CPU1 can't support Closed switch Retention (CSWR)
* because the mode is not supported by hw constraints of dormant
* mode. While waking up from the dormant mode, a reset signal
* to the Cortex-A9 processor must be asserted by the external
* power controller.
*
* With architectural inputs and hardware recommendations, only
* below modes are supported from power gain vs latency point of view.
*
* CPU0 CPU1 MPUSS
* ----------------------------------------------
* ON ON ON
* ON(Inactive) OFF ON(Inactive)
* OFF OFF CSWR
* OFF OFF OSWR
* OFF OFF OFF(Device OFF *TBD)
* ----------------------------------------------
*
* Note: CPU0 is the master core and it is the last CPU to go down
* and first to wake-up when MPUSS low power states are excercised
*
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/io.h>
#include <linux/errno.h>
#include <linux/linkage.h>
#include <linux/smp.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/smp_scu.h>
#include <asm/pgalloc.h>
#include <asm/suspend.h>
#include <asm/hardware/cache-l2x0.h>
#include "soc.h"
#include "common.h"
#include "omap44xx.h"
#include "omap4-sar-layout.h"
#include "pm.h"
#include "prcm_mpu44xx.h"
#include "prcm_mpu54xx.h"
#include "prminst44xx.h"
#include "prcm44xx.h"
#include "prm44xx.h"
#include "prm-regbits-44xx.h"
#ifdef CONFIG_SMP
struct omap4_cpu_pm_info {
struct powerdomain *pwrdm;
void __iomem *scu_sar_addr;
void __iomem *wkup_sar_addr;
void __iomem *l2x0_sar_addr;
};
/**
* struct cpu_pm_ops - CPU pm operations
* @finish_suspend: CPU suspend finisher function pointer
* @resume: CPU resume function pointer
* @scu_prepare: CPU Snoop Control program function pointer
* @hotplug_restart: CPU restart function pointer
*
* Structure holds functions pointer for CPU low power operations like
* suspend, resume and scu programming.
*/
struct cpu_pm_ops {
int (*finish_suspend)(unsigned long cpu_state);
void (*resume)(void);
void (*scu_prepare)(unsigned int cpu_id, unsigned int cpu_state);
void (*hotplug_restart)(void);
};
static DEFINE_PER_CPU(struct omap4_cpu_pm_info, omap4_pm_info);
static struct powerdomain *mpuss_pd;
static void __iomem *sar_base;
static u32 cpu_context_offset;
static int default_finish_suspend(unsigned long cpu_state)
{
omap_do_wfi();
return 0;
}
static void dummy_cpu_resume(void)
{}
static void dummy_scu_prepare(unsigned int cpu_id, unsigned int cpu_state)
{}
struct cpu_pm_ops omap_pm_ops = {
.finish_suspend = default_finish_suspend,
.resume = dummy_cpu_resume,
.scu_prepare = dummy_scu_prepare,
.hotplug_restart = dummy_cpu_resume,
};
/*
* Program the wakeup routine address for the CPU0 and CPU1
* used for OFF or DORMANT wakeup.
*/
static inline void set_cpu_wakeup_addr(unsigned int cpu_id, u32 addr)
{
struct omap4_cpu_pm_info *pm_info = &per_cpu(omap4_pm_info, cpu_id);
if (pm_info->wkup_sar_addr)
writel_relaxed(addr, pm_info->wkup_sar_addr);
}
/*
* Store the SCU power status value to scratchpad memory
*/
static void scu_pwrst_prepare(unsigned int cpu_id, unsigned int cpu_state)
{
struct omap4_cpu_pm_info *pm_info = &per_cpu(omap4_pm_info, cpu_id);
u32 scu_pwr_st;
switch (cpu_state) {
case PWRDM_POWER_RET:
scu_pwr_st = SCU_PM_DORMANT;
break;
case PWRDM_POWER_OFF:
scu_pwr_st = SCU_PM_POWEROFF;
break;
case PWRDM_POWER_ON:
case PWRDM_POWER_INACTIVE:
default:
scu_pwr_st = SCU_PM_NORMAL;
break;
}
if (pm_info->scu_sar_addr)
writel_relaxed(scu_pwr_st, pm_info->scu_sar_addr);
}
/* Helper functions for MPUSS OSWR */
static inline void mpuss_clear_prev_logic_pwrst(void)
{
u32 reg;
reg = omap4_prminst_read_inst_reg(OMAP4430_PRM_PARTITION,
OMAP4430_PRM_MPU_INST, OMAP4_RM_MPU_MPU_CONTEXT_OFFSET);
omap4_prminst_write_inst_reg(reg, OMAP4430_PRM_PARTITION,
OMAP4430_PRM_MPU_INST, OMAP4_RM_MPU_MPU_CONTEXT_OFFSET);
}
static inline void cpu_clear_prev_logic_pwrst(unsigned int cpu_id)
{
u32 reg;
if (cpu_id) {
reg = omap4_prcm_mpu_read_inst_reg(OMAP4430_PRCM_MPU_CPU1_INST,
cpu_context_offset);
omap4_prcm_mpu_write_inst_reg(reg, OMAP4430_PRCM_MPU_CPU1_INST,
cpu_context_offset);
} else {
reg = omap4_prcm_mpu_read_inst_reg(OMAP4430_PRCM_MPU_CPU0_INST,
cpu_context_offset);
omap4_prcm_mpu_write_inst_reg(reg, OMAP4430_PRCM_MPU_CPU0_INST,
cpu_context_offset);
}
}
/*
* Store the CPU cluster state for L2X0 low power operations.
*/
static void l2x0_pwrst_prepare(unsigned int cpu_id, unsigned int save_state)
{
struct omap4_cpu_pm_info *pm_info = &per_cpu(omap4_pm_info, cpu_id);
if (pm_info->l2x0_sar_addr)
writel_relaxed(save_state, pm_info->l2x0_sar_addr);
}
/*
* Save the L2X0 AUXCTRL and POR value to SAR memory. Its used to
* in every restore MPUSS OFF path.
*/
#ifdef CONFIG_CACHE_L2X0
static void __init save_l2x0_context(void)
{
void __iomem *l2x0_base = omap4_get_l2cache_base();
if (l2x0_base && sar_base) {
writel_relaxed(l2x0_saved_regs.aux_ctrl,
sar_base + L2X0_AUXCTRL_OFFSET);
writel_relaxed(l2x0_saved_regs.prefetch_ctrl,
sar_base + L2X0_PREFETCH_CTRL_OFFSET);
}
}
#else
static void __init save_l2x0_context(void)
{}
#endif
/**
* omap4_enter_lowpower: OMAP4 MPUSS Low Power Entry Function
* The purpose of this function is to manage low power programming
* of OMAP4 MPUSS subsystem
* @cpu : CPU ID
* @power_state: Low power state.
*
* MPUSS states for the context save:
* save_state =
* 0 - Nothing lost and no need to save: MPUSS INACTIVE
* 1 - CPUx L1 and logic lost: MPUSS CSWR
* 2 - CPUx L1 and logic lost + GIC lost: MPUSS OSWR
* 3 - CPUx L1 and logic lost + GIC + L2 lost: DEVICE OFF
*/
int omap4_enter_lowpower(unsigned int cpu, unsigned int power_state)
{
struct omap4_cpu_pm_info *pm_info = &per_cpu(omap4_pm_info, cpu);
unsigned int save_state = 0, cpu_logic_state = PWRDM_POWER_RET;
unsigned int wakeup_cpu;
if (omap_rev() == OMAP4430_REV_ES1_0)
return -ENXIO;
switch (power_state) {
case PWRDM_POWER_ON:
case PWRDM_POWER_INACTIVE:
save_state = 0;
break;
case PWRDM_POWER_OFF:
cpu_logic_state = PWRDM_POWER_OFF;
save_state = 1;
break;
case PWRDM_POWER_RET:
if (IS_PM44XX_ERRATUM(PM_OMAP4_CPU_OSWR_DISABLE)) {
save_state = 0;
break;
}
default:
/*
* CPUx CSWR is invalid hardware state. Also CPUx OSWR
* doesn't make much scense, since logic is lost and $L1
* needs to be cleaned because of coherency. This makes
* CPUx OSWR equivalent to CPUX OFF and hence not supported
*/
WARN_ON(1);
return -ENXIO;
}
pwrdm_pre_transition(NULL);
/*
* Check MPUSS next state and save interrupt controller if needed.
* In MPUSS OSWR or device OFF, interrupt controller contest is lost.
*/
mpuss_clear_prev_logic_pwrst();
if ((pwrdm_read_next_pwrst(mpuss_pd) == PWRDM_POWER_RET) &&
(pwrdm_read_logic_retst(mpuss_pd) == PWRDM_POWER_OFF))
save_state = 2;
cpu_clear_prev_logic_pwrst(cpu);
pwrdm_set_next_pwrst(pm_info->pwrdm, power_state);
pwrdm_set_logic_retst(pm_info->pwrdm, cpu_logic_state);
set_cpu_wakeup_addr(cpu, virt_to_phys(omap_pm_ops.resume));
omap_pm_ops.scu_prepare(cpu, power_state);
l2x0_pwrst_prepare(cpu, save_state);
/*
* Call low level function with targeted low power state.
*/
if (save_state)
cpu_suspend(save_state, omap_pm_ops.finish_suspend);
else
omap_pm_ops.finish_suspend(save_state);
if (IS_PM44XX_ERRATUM(PM_OMAP4_ROM_SMP_BOOT_ERRATUM_GICD) && cpu)
gic_dist_enable();
/*
* Restore the CPUx power state to ON otherwise CPUx
* power domain can transitions to programmed low power
* state while doing WFI outside the low powe code. On
* secure devices, CPUx does WFI which can result in
* domain transition
*/
wakeup_cpu = smp_processor_id();
pwrdm_set_next_pwrst(pm_info->pwrdm, PWRDM_POWER_ON);
pwrdm_post_transition(NULL);
return 0;
}
/**
* omap4_hotplug_cpu: OMAP4 CPU hotplug entry
* @cpu : CPU ID
* @power_state: CPU low power state.
*/
int omap4_hotplug_cpu(unsigned int cpu, unsigned int power_state)
{
struct omap4_cpu_pm_info *pm_info = &per_cpu(omap4_pm_info, cpu);
unsigned int cpu_state = 0;
if (omap_rev() == OMAP4430_REV_ES1_0)
return -ENXIO;
/* Use the achievable power state for the domain */
power_state = pwrdm_get_valid_lp_state(pm_info->pwrdm,
false, power_state);
if (power_state == PWRDM_POWER_OFF)
cpu_state = 1;
pwrdm_clear_all_prev_pwrst(pm_info->pwrdm);
pwrdm_set_next_pwrst(pm_info->pwrdm, power_state);
set_cpu_wakeup_addr(cpu, virt_to_phys(omap_pm_ops.hotplug_restart));
omap_pm_ops.scu_prepare(cpu, power_state);
/*
* CPU never retuns back if targeted power state is OFF mode.
* CPU ONLINE follows normal CPU ONLINE ptah via
* omap4_secondary_startup().
*/
omap_pm_ops.finish_suspend(cpu_state);
pwrdm_set_next_pwrst(pm_info->pwrdm, PWRDM_POWER_ON);
return 0;
}
/*
* Enable Mercury Fast HG retention mode by default.
*/
static void enable_mercury_retention_mode(void)
{
u32 reg;
reg = omap4_prcm_mpu_read_inst_reg(OMAP54XX_PRCM_MPU_DEVICE_INST,
OMAP54XX_PRCM_MPU_PRM_PSCON_COUNT_OFFSET);
/* Enable HG_EN, HG_RAMPUP = fast mode */
reg |= BIT(24) | BIT(25);
omap4_prcm_mpu_write_inst_reg(reg, OMAP54XX_PRCM_MPU_DEVICE_INST,
OMAP54XX_PRCM_MPU_PRM_PSCON_COUNT_OFFSET);
}
/*
* Initialise OMAP4 MPUSS
*/
int __init omap4_mpuss_init(void)
{
struct omap4_cpu_pm_info *pm_info;
if (omap_rev() == OMAP4430_REV_ES1_0) {
WARN(1, "Power Management not supported on OMAP4430 ES1.0\n");
return -ENODEV;
}
if (cpu_is_omap44xx())
sar_base = omap4_get_sar_ram_base();
/* Initilaise per CPU PM information */
pm_info = &per_cpu(omap4_pm_info, 0x0);
if (sar_base) {
pm_info->scu_sar_addr = sar_base + SCU_OFFSET0;
pm_info->wkup_sar_addr = sar_base +
CPU0_WAKEUP_NS_PA_ADDR_OFFSET;
pm_info->l2x0_sar_addr = sar_base + L2X0_SAVE_OFFSET0;
}
pm_info->pwrdm = pwrdm_lookup("cpu0_pwrdm");
if (!pm_info->pwrdm) {
pr_err("Lookup failed for CPU0 pwrdm\n");
return -ENODEV;
}
/* Clear CPU previous power domain state */
pwrdm_clear_all_prev_pwrst(pm_info->pwrdm);
cpu_clear_prev_logic_pwrst(0);
/* Initialise CPU0 power domain state to ON */
pwrdm_set_next_pwrst(pm_info->pwrdm, PWRDM_POWER_ON);
pm_info = &per_cpu(omap4_pm_info, 0x1);
if (sar_base) {
pm_info->scu_sar_addr = sar_base + SCU_OFFSET1;
pm_info->wkup_sar_addr = sar_base +
CPU1_WAKEUP_NS_PA_ADDR_OFFSET;
pm_info->l2x0_sar_addr = sar_base + L2X0_SAVE_OFFSET1;
}
pm_info->pwrdm = pwrdm_lookup("cpu1_pwrdm");
if (!pm_info->pwrdm) {
pr_err("Lookup failed for CPU1 pwrdm\n");
return -ENODEV;
}
/* Clear CPU previous power domain state */
pwrdm_clear_all_prev_pwrst(pm_info->pwrdm);
cpu_clear_prev_logic_pwrst(1);
/* Initialise CPU1 power domain state to ON */
pwrdm_set_next_pwrst(pm_info->pwrdm, PWRDM_POWER_ON);
mpuss_pd = pwrdm_lookup("mpu_pwrdm");
if (!mpuss_pd) {
pr_err("Failed to lookup MPUSS power domain\n");
return -ENODEV;
}
pwrdm_clear_all_prev_pwrst(mpuss_pd);
mpuss_clear_prev_logic_pwrst();
if (sar_base) {
/* Save device type on scratchpad for low level code to use */
writel_relaxed((omap_type() != OMAP2_DEVICE_TYPE_GP) ? 1 : 0,
sar_base + OMAP_TYPE_OFFSET);
save_l2x0_context();
}
if (cpu_is_omap44xx()) {
omap_pm_ops.finish_suspend = omap4_finish_suspend;
omap_pm_ops.resume = omap4_cpu_resume;
omap_pm_ops.scu_prepare = scu_pwrst_prepare;
omap_pm_ops.hotplug_restart = omap4_secondary_startup;
cpu_context_offset = OMAP4_RM_CPU0_CPU0_CONTEXT_OFFSET;
} else if (soc_is_omap54xx() || soc_is_dra7xx()) {
cpu_context_offset = OMAP54XX_RM_CPU0_CPU0_CONTEXT_OFFSET;
enable_mercury_retention_mode();
}
if (cpu_is_omap446x())
omap_pm_ops.hotplug_restart = omap4460_secondary_startup;
return 0;
}
#endif
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