[PATCH v3 38/51] cpuidle,omap4: Push RCU-idle into omap4_enter_lowpower()

Peter Zijlstra
2023-01-12T20:05:15Z

From: Tony Lindgren <tony@atomide.com>

OMAP4 uses full SoC suspend modes as idle states, as such it needs the
whole power-domain and clock-domain code from the idle path.

All that code is not suitable to run with RCU disabled, as such push
RCU-idle deeper still.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lkml.kernel.org/r/Yqcv6crSNKuSWoTu@atomide.com
---
arch/arm/mach-omap2/common.h | 6 ++++--
arch/arm/mach-omap2/cpuidle44xx.c | 8 ++------
arch/arm/mach-omap2/omap-mpuss-lowpower.c | 12 +++++++++++-
arch/arm/mach-omap2/pm44xx.c | 2 +-
4 files changed, 18 insertions(+), 10 deletions(-)

--- a/arch/arm/mach-omap2/common.h
+++ b/arch/arm/mach-omap2/common.h
@@ -284,11 +284,13 @@ extern u32 omap4_get_cpu1_ns_pa_addr(voi

#if defined(CONFIG_SMP) && defined(CONFIG_PM)
extern int omap4_mpuss_init(void);
-extern int omap4_enter_lowpower(unsigned int cpu, unsigned int power_state);
+extern int omap4_enter_lowpower(unsigned int cpu, unsigned int power_state,
+ bool rcuidle);
extern int omap4_hotplug_cpu(unsigned int cpu, unsigned int power_state);
#else
static inline int omap4_enter_lowpower(unsigned int cpu,
- unsigned int power_state)
+ unsigned int power_state,
+ bool rcuidle)
{
cpu_do_idle();
return 0;
--- a/arch/arm/mach-omap2/cpuidle44xx.c
+++ b/arch/arm/mach-omap2/cpuidle44xx.c
@@ -105,9 +105,7 @@ static int omap_enter_idle_smp(struct cp
}
raw_spin_unlock_irqrestore(&mpu_lock, flag);

- ct_cpuidle_enter();
- omap4_enter_lowpower(dev->cpu, cx->cpu_state);
- ct_cpuidle_exit();
+ omap4_enter_lowpower(dev->cpu, cx->cpu_state, true);

raw_spin_lock_irqsave(&mpu_lock, flag);
if (cx->mpu_state_vote == num_online_cpus())
@@ -186,10 +184,8 @@ static int omap_enter_idle_coupled(struc
}
}

- ct_cpuidle_enter();
- omap4_enter_lowpower(dev->cpu, cx->cpu_state);
+ omap4_enter_lowpower(dev->cpu, cx->cpu_state, true);
cpu_done[dev->cpu] = true;
- ct_cpuidle_exit();

/* Wakeup CPU1 only if it is not offlined */
if (dev->cpu == 0 && cpumask_test_cpu(1, cpu_online_mask)) {
--- a/arch/arm/mach-omap2/omap-mpuss-lowpower.c
+++ b/arch/arm/mach-omap2/omap-mpuss-lowpower.c
@@ -33,6 +33,7 @@
* and first to wake-up when MPUSS low power states are excercised
*/

+#include <linux/cpuidle.h>
#include <linux/kernel.h>
#include <linux/io.h>
#include <linux/errno.h>
@@ -214,6 +215,7 @@ static void __init save_l2x0_context(voi
* of OMAP4 MPUSS subsystem
* @cpu : CPU ID
* @power_state: Low power state.
+ * @rcuidle: RCU needs to be idled
*
* MPUSS states for the context save:
* save_state =
@@ -222,7 +224,8 @@ static void __init save_l2x0_context(voi
* 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)
+int omap4_enter_lowpower(unsigned int cpu, unsigned int power_state,
+ bool rcuidle)
{
struct omap4_cpu_pm_info *pm_info = &per_cpu(omap4_pm_info, cpu);
unsigned int save_state = 0, cpu_logic_state = PWRDM_POWER_RET;
@@ -268,6 +271,10 @@ int omap4_enter_lowpower(unsigned int cp
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);
+
+ if (rcuidle)
+ ct_cpuidle_enter();
+
set_cpu_wakeup_addr(cpu, __pa_symbol(omap_pm_ops.resume));
omap_pm_ops.scu_prepare(cpu, power_state);
l2x0_pwrst_prepare(cpu, save_state);
@@ -283,6 +290,9 @@ int omap4_enter_lowpower(unsigned int cp
if (IS_PM44XX_ERRATUM(PM_OMAP4_ROM_SMP_BOOT_ERRATUM_GICD) && cpu)
gic_dist_enable();

+ if (rcuidle)
+ ct_cpuidle_exit();
+
/*
* Restore the CPUx power state to ON otherwise CPUx
* power domain can transitions to programmed low power
--- a/arch/arm/mach-omap2/pm44xx.c
+++ b/arch/arm/mach-omap2/pm44xx.c
@@ -76,7 +76,7 @@ static int omap4_pm_suspend(void)
* domain CSWR is not supported by hardware.
* More details can be found in OMAP4430 TRM section 4.3.4.2.
*/
- omap4_enter_lowpower(cpu_id, cpu_suspend_state);
+ omap4_enter_lowpower(cpu_id, cpu_suspend_state, false);

/* Restore next powerdomain state */
list_for_each_entry(pwrst, &pwrst_list, node) {