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ARM: mvebu: Disable CPU Idle on Armada 38x

PATCH Superseded Gregory CLEMENT 2 participants 3 messages Feb 25, 2015 – Mar 31, 2015

Subsystems (3)
Arm (32-bit) Arm sub-architectures Arm/Marvell Kirkwood and Armada 370, 375, 38x, 39x, XP, 3700, 7K/8K, CN9130 SoC support

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Gregory CLEMENT

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#0 lore raw

PATCH v2 1/1 ARM: mvebu: Disable CPU Idle on Armada 38x

On Armada 38x SoCs, under heavy I/O load, the system hangs when CPU Idle is enabled. Waiting for a solution to this issue, this patch disables the CPU Idle support for this SoC.

As CPU Hot plug support also uses some of the CPU Idle functions it is also affected by the same issue. This patch disables it also for the Armada 38x SoCs.

Signed-off-by Gregory CLEMENT <[email protected]>
Cc <[email protected]> # v3.17 +

---
Hi,

The previous code raised a warning about the unused armada_38x_cpuidle_init() function. So I moved the warn message inside the function itself and then I continued to call this function.

I also fixed a missing bracket.

And finally I only registered the cpuilde platform driver if there was really something to register.

Gregory

 arch/arm/mach-mvebu/pmsu.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)
arch/arm/mach-mvebu/pmsu.c +16 -2
index 8b9f5e202ccf..2145f192662f 100644
@@ -415,6 +415,9 @@ static __init int armada_38x_cpuidle_init(void)
 	void __iomem *mpsoc_base;
 	u32 reg;
 
+	pr_warn("CPU Idle is currently broken on Armada 38x: disabling");
+	return 0;
+
 	np = of_find_compatible_node(NULL, NULL,
 				     "marvell,armada-380-coherency-fabric");
 	if (!np)

@@ -469,13 +472,23 @@ static __init int armada_xp_cpuidle_init(void)
 static int __init mvebu_v7_cpu_pm_init(void)
 {
 	struct device_node *np;
-	int ret;
+	int ret = 0;
 
 	np = of_find_matching_node(NULL, of_pmsu_table);
 	if (!np)
 		return 0;
 	of_node_put(np);
 
+	/*
+	 * Currently the CPU Idle support for Armada 38x is broken, as
+	 * the CPU Hotplug uses some of the CPU Idle functions it is
+	 * broken too, so let's disable it
+	 */
+	if (of_machine_is_compatible("marvell,armada380")) {
+		cpu_hotplug_disable();
+		pr_warn("CPU Hotplug support is currently broken on Armada 38x: disabling");
+	}
+
 	if (of_machine_is_compatible("marvell,armadaxp"))
 		ret = armada_xp_cpuidle_init();
 	else if (of_machine_is_compatible("marvell,armada370"))

@@ -489,7 +502,8 @@ static int __init mvebu_v7_cpu_pm_init(void)
 		return ret;
 
 	mvebu_v7_pmsu_enable_l2_powerdown_onidle();
-	platform_device_register(&mvebu_v7_cpuidle_device);
+	if (mvebu_v7_cpuidle_device.name)
+		platform_device_register(&mvebu_v7_cpuidle_device);
 	cpu_pm_register_notifier(&mvebu_v7_cpu_pm_notifier);
 
 	return 0;
Signature · 1 line
2.1.0
#1 lore raw

PATCH v2 1/1 ARM: mvebu: Disable CPU Idle on Armada 38x

Dear Gregory CLEMENT,

Quoted 10 lines · Gregory CLEMENT

On Armada 38x SoCs, under heavy I/O load, the system hangs when CPU Idle is enabled. Waiting for a solution to this issue, this patch disables the CPU Idle support for this SoC.

As CPU Hot plug support also uses some of the CPU Idle functions it is also affected by the same issue. This patch disables it also for the Armada 38x SoCs.

Signed-off-by Gregory CLEMENT <[email protected]>
Cc <[email protected]> # v3.17 +
Tested-by Thomas Petazzoni <[email protected]>

I tested on Armada 38x, and indeed CPU hotplug is properly disabled, and it doesn't prevent suspend/resume (not supported yet in mainline, but hopefully soon to be supported).

Some minor comments below.

arch/arm/mach-mvebu/pmsu.c static __init int armada_38x_cpuidle_init(void) · line 418

Quoted 9 lines
arch/arm/mach-mvebu/pmsu.c +1 -0
index 8b9f5e202ccf..2145f192662f 100644
@@ -415,6 +415,9 @@ static __init int armada_38x_cpuidle_init(void)
 	void __iomem *mpsoc_base;
 	u32 reg;
 
+	pr_warn("CPU Idle is currently broken on Armada 38x: disabling");

Idle -> idle

arch/arm/mach-mvebu/pmsu.c static __init int armada_xp_cpuidle_init(void) · line 475

Quoted 11 lines
arch/arm/mach-mvebu/pmsu.c +3 -1
+	return 0;
+
 	np = of_find_compatible_node(NULL, NULL,
 				     "marvell,armada-380-coherency-fabric");
 	if (!np)

@@ -469,13 +472,23 @@ static __init int armada_xp_cpuidle_init(void)
 static int __init mvebu_v7_cpu_pm_init(void)
 {
 	struct device_node *np;
-	int ret;
+	int ret = 0;

Not clear why this change is needed.

Quoted 4 lines
arch/arm/mach-mvebu/pmsu.c +0 -0
 	np = of_find_matching_node(NULL, of_pmsu_table);
 	if (!np)
 		return 0;

arch/arm/mach-mvebu/pmsu.c static __init int armada_xp_cpuidle_init(void) · line 489

Quoted 10 lines
arch/arm/mach-mvebu/pmsu.c +8 -0
 	of_node_put(np);
 
+	/*
+	 * Currently the CPU Idle support for Armada 38x is broken, as
+	 * the CPU Hotplug uses some of the CPU Idle functions it is
+	 * broken too, so let's disable it
+	 */
+	if (of_machine_is_compatible("marvell,armada380")) {
+		cpu_hotplug_disable();
+		pr_warn("CPU Hotplug support is currently broken on Armada 38x: disabling");

Hotplug -> hotplug.

Thanks,

Thomas

Signature · 3 lines
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
author
#2 lore raw

PATCH v2 1/1 ARM: mvebu: Disable CPU Idle on Armada 38x

Hi Thomas,

Quoted 11 lines · Thomas Petazzoni

Dear Gregory CLEMENT,

Quoted 8 lines · Gregory CLEMENT

On Armada 38x SoCs, under heavy I/O load, the system hangs when CPU Idle is enabled. Waiting for a solution to this issue, this patch disables the CPU Idle support for this SoC.

As CPU Hot plug support also uses some of the CPU Idle functions it is also affected by the same issue. This patch disables it also for the Armada 38x SoCs.

Quoted 8 lines
Quoted 2 lines
Signed-off-by Gregory CLEMENT <[email protected]>
Cc <[email protected]> # v3.17 +
Tested-by Thomas Petazzoni <[email protected]>

I tested on Armada 38x, and indeed CPU hotplug is properly disabled, and it doesn't prevent suspend/resume (not supported yet in mainline, but hopefully soon to be supported).

Great!

Quoted 11 lines

Some minor comments below.

Quoted 8 lines
arch/arm/mach-mvebu/pmsu.c +0 -0
index 8b9f5e202ccf..2145f192662f 100644
@@ -415,6 +415,9 @@ static __init int armada_38x_cpuidle_init(void)
 	void __iomem *mpsoc_base;
 	u32 reg;
Quoted 4 lines

arch/arm/mach-mvebu/pmsu.c static __init int armada_38x_cpuidle_init(void) · line 418

Quoted 1 line
arch/arm/mach-mvebu/pmsu.c +1 -0
+	pr_warn("CPU Idle is currently broken on Armada 38x: disabling");

Idle -> idle

OK

Quoted 5 lines
Quoted 5 lines
arch/arm/mach-mvebu/pmsu.c +2 -0
+	return 0;
+
 	np = of_find_compatible_node(NULL, NULL,
 				     "marvell,armada-380-coherency-fabric");
 	if (!np)
Quoted 8 lines

arch/arm/mach-mvebu/pmsu.c static __init int armada_xp_cpuidle_init(void) · line 475

Quoted 6 lines
arch/arm/mach-mvebu/pmsu.c +1 -1
@@ -469,13 +472,23 @@ static __init int armada_xp_cpuidle_init(void)
 static int __init mvebu_v7_cpu_pm_init(void)
 {
 	struct device_node *np;
-	int ret;
+	int ret = 0;

Not clear why this change is needed.

It was a left over of an older version I will remove it.

Quoted 7 lines
Quoted 7 lines
arch/arm/mach-mvebu/pmsu.c +0 -0
 	np = of_find_matching_node(NULL, of_pmsu_table);
 	if (!np)
 		return 0;
 	of_node_put(np);
Quoted 10 lines

arch/arm/mach-mvebu/pmsu.c static __init int armada_xp_cpuidle_init(void) · line 489

Quoted 8 lines
arch/arm/mach-mvebu/pmsu.c +8 -0
+	/*
+	 * Currently the CPU Idle support for Armada 38x is broken, as
+	 * the CPU Hotplug uses some of the CPU Idle functions it is
+	 * broken too, so let's disable it
+	 */
+	if (of_machine_is_compatible("marvell,armada380")) {
+		cpu_hotplug_disable();
+		pr_warn("CPU Hotplug support is currently broken on Armada 38x: disabling");

Hotplug -> hotplug.

OK

Thanks,

Gregory

Signature · 4 lines
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com