[PATCH v6 3/6] genirq/PM: Introduce IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND flag

From: Maulik Shah
Date: Mon Sep 28 2020 - 00:32:43 EST


An interrupt that is disabled/masked but set for wakeup still needs to
be able to wake up the system from sleep states like "suspend to RAM".

This change introduces IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND flag. If irqchip
have this flag set then irq PM will enable/unmask irqs that are marked
for wakeup but are in disabled state.

On resume such irqs will be restored back to disabled state.

Suggested-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Maulik Shah <mkshah@xxxxxxxxxxxxxx>
---
include/linux/irq.h | 49 ++++++++++++++++++++++++++++++-------------------
kernel/irq/debugfs.c | 3 +++
kernel/irq/pm.c | 34 ++++++++++++++++++++++++++++++----
3 files changed, 63 insertions(+), 23 deletions(-)

diff --git a/include/linux/irq.h b/include/linux/irq.h
index 63b9d96..ccd39e2 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -217,6 +217,8 @@ struct irq_data {
* from actual interrupt context.
* IRQD_AFFINITY_ON_ACTIVATE - Affinity is set on activation. Don't call
* irq_chip::irq_set_affinity() when deactivated.
+ * IRQD_IRQ_ENABLED_ON_SUSPEND - Interrupt is enabled on suspend by irq pm if
+ * irqchip have flag IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND set.
*/
enum {
IRQD_TRIGGER_MASK = 0xf,
@@ -242,6 +244,7 @@ enum {
IRQD_MSI_NOMASK_QUIRK = (1 << 27),
IRQD_HANDLE_ENFORCE_IRQCTX = (1 << 28),
IRQD_AFFINITY_ON_ACTIVATE = (1 << 29),
+ IRQD_IRQ_ENABLED_ON_SUSPEND = (1 << 30),
};

#define __irqd_to_state(d) ACCESS_PRIVATE((d)->common, state_use_accessors)
@@ -321,6 +324,11 @@ static inline bool irqd_is_handle_enforce_irqctx(struct irq_data *d)
return __irqd_to_state(d) & IRQD_HANDLE_ENFORCE_IRQCTX;
}

+static inline bool irqd_is_enabled_on_suspend(struct irq_data *d)
+{
+ return __irqd_to_state(d) & IRQD_IRQ_ENABLED_ON_SUSPEND;
+}
+
static inline bool irqd_is_wakeup_set(struct irq_data *d)
{
return __irqd_to_state(d) & IRQD_WAKEUP_STATE;
@@ -547,27 +555,30 @@ struct irq_chip {
/*
* irq_chip specific flags
*
- * IRQCHIP_SET_TYPE_MASKED: Mask before calling chip.irq_set_type()
- * IRQCHIP_EOI_IF_HANDLED: Only issue irq_eoi() when irq was handled
- * IRQCHIP_MASK_ON_SUSPEND: Mask non wake irqs in the suspend path
- * IRQCHIP_ONOFFLINE_ENABLED: Only call irq_on/off_line callbacks
- * when irq enabled
- * IRQCHIP_SKIP_SET_WAKE: Skip chip.irq_set_wake(), for this irq chip
- * IRQCHIP_ONESHOT_SAFE: One shot does not require mask/unmask
- * IRQCHIP_EOI_THREADED: Chip requires eoi() on unmask in threaded mode
- * IRQCHIP_SUPPORTS_LEVEL_MSI Chip can provide two doorbells for Level MSIs
- * IRQCHIP_SUPPORTS_NMI: Chip can deliver NMIs, only for root irqchips
+ * IRQCHIP_SET_TYPE_MASKED: Mask before calling chip.irq_set_type()
+ * IRQCHIP_EOI_IF_HANDLED: Only issue irq_eoi() when irq was handled
+ * IRQCHIP_MASK_ON_SUSPEND: Mask non wake irqs in the suspend path
+ * IRQCHIP_ONOFFLINE_ENABLED: Only call irq_on/off_line callbacks
+ * when irq enabled
+ * IRQCHIP_SKIP_SET_WAKE: Skip chip.irq_set_wake(), for this irq chip
+ * IRQCHIP_ONESHOT_SAFE: One shot does not require mask/unmask
+ * IRQCHIP_EOI_THREADED: Chip requires eoi() on unmask in threaded mode
+ * IRQCHIP_SUPPORTS_LEVEL_MSI: Chip can provide two doorbells for Level MSIs
+ * IRQCHIP_SUPPORTS_NMI: Chip can deliver NMIs, only for root irqchips
+ * IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND: Invokes __enable_irq()/__disable_irq() for wake irqs
+ * in the suspend path if they are in disabled state
*/
enum {
- IRQCHIP_SET_TYPE_MASKED = (1 << 0),
- IRQCHIP_EOI_IF_HANDLED = (1 << 1),
- IRQCHIP_MASK_ON_SUSPEND = (1 << 2),
- IRQCHIP_ONOFFLINE_ENABLED = (1 << 3),
- IRQCHIP_SKIP_SET_WAKE = (1 << 4),
- IRQCHIP_ONESHOT_SAFE = (1 << 5),
- IRQCHIP_EOI_THREADED = (1 << 6),
- IRQCHIP_SUPPORTS_LEVEL_MSI = (1 << 7),
- IRQCHIP_SUPPORTS_NMI = (1 << 8),
+ IRQCHIP_SET_TYPE_MASKED = (1 << 0),
+ IRQCHIP_EOI_IF_HANDLED = (1 << 1),
+ IRQCHIP_MASK_ON_SUSPEND = (1 << 2),
+ IRQCHIP_ONOFFLINE_ENABLED = (1 << 3),
+ IRQCHIP_SKIP_SET_WAKE = (1 << 4),
+ IRQCHIP_ONESHOT_SAFE = (1 << 5),
+ IRQCHIP_EOI_THREADED = (1 << 6),
+ IRQCHIP_SUPPORTS_LEVEL_MSI = (1 << 7),
+ IRQCHIP_SUPPORTS_NMI = (1 << 8),
+ IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND = (1 << 9),
};

#include <linux/irqdesc.h>
diff --git a/kernel/irq/debugfs.c b/kernel/irq/debugfs.c
index acabc0c..e4cff35 100644
--- a/kernel/irq/debugfs.c
+++ b/kernel/irq/debugfs.c
@@ -57,6 +57,7 @@ static const struct irq_bit_descr irqchip_flags[] = {
BIT_MASK_DESCR(IRQCHIP_EOI_THREADED),
BIT_MASK_DESCR(IRQCHIP_SUPPORTS_LEVEL_MSI),
BIT_MASK_DESCR(IRQCHIP_SUPPORTS_NMI),
+ BIT_MASK_DESCR(IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND),
};

static void
@@ -125,6 +126,8 @@ static const struct irq_bit_descr irqdata_states[] = {
BIT_MASK_DESCR(IRQD_DEFAULT_TRIGGER_SET),

BIT_MASK_DESCR(IRQD_HANDLE_ENFORCE_IRQCTX),
+
+ BIT_MASK_DESCR(IRQD_IRQ_ENABLED_ON_SUSPEND),
};

static const struct irq_bit_descr irqdesc_states[] = {
diff --git a/kernel/irq/pm.c b/kernel/irq/pm.c
index c6c7e18..ce0adb2 100644
--- a/kernel/irq/pm.c
+++ b/kernel/irq/pm.c
@@ -69,12 +69,26 @@ void irq_pm_remove_action(struct irq_desc *desc, struct irqaction *action)

static bool suspend_device_irq(struct irq_desc *desc)
{
+ unsigned long chipflags = irq_desc_get_chip(desc)->flags;
+ struct irq_data *irqd = &desc->irq_data;
+
if (!desc->action || irq_desc_is_chained(desc) ||
desc->no_suspend_depth)
return false;

- if (irqd_is_wakeup_set(&desc->irq_data)) {
- irqd_set(&desc->irq_data, IRQD_WAKEUP_ARMED);
+ if (irqd_is_wakeup_set(irqd)) {
+ irqd_set(irqd, IRQD_WAKEUP_ARMED);
+
+ if ((chipflags & IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND) &&
+ irqd_irq_disabled(irqd)) {
+ /*
+ * Interrupt marked for wakeup is in disabled state.
+ * Enable interrupt here to unmask/enable in irqchip
+ * to be able to resume with such interrupts.
+ */
+ __enable_irq(desc);
+ irqd_set(irqd, IRQD_IRQ_ENABLED_ON_SUSPEND);
+ }
/*
* We return true here to force the caller to issue
* synchronize_irq(). We need to make sure that the
@@ -93,7 +107,7 @@ static bool suspend_device_irq(struct irq_desc *desc)
* chip level. The chip implementation indicates that with
* IRQCHIP_MASK_ON_SUSPEND.
*/
- if (irq_desc_get_chip(desc)->flags & IRQCHIP_MASK_ON_SUSPEND)
+ if (chipflags & IRQCHIP_MASK_ON_SUSPEND)
mask_irq(desc);
return true;
}
@@ -137,7 +151,19 @@ EXPORT_SYMBOL_GPL(suspend_device_irqs);

static void resume_irq(struct irq_desc *desc)
{
- irqd_clear(&desc->irq_data, IRQD_WAKEUP_ARMED);
+ struct irq_data *irqd = &desc->irq_data;
+
+ irqd_clear(irqd, IRQD_WAKEUP_ARMED);
+
+ if (irqd_is_enabled_on_suspend(irqd)) {
+ /*
+ * Interrupt marked for wakeup was enabled during suspend
+ * entry. Disable such interrupts to restore them back to
+ * original state.
+ */
+ __disable_irq(desc);
+ irqd_clear(irqd, IRQD_IRQ_ENABLED_ON_SUSPEND);
+ }

if (desc->istate & IRQS_SUSPENDED)
goto resume;
--
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