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Subject[patch 07/52] genirq: Separate activation and startup
Activation of an interrupt and startup are currently a combo
functionlity. That works so far, but upcoming changes require a strict
separation because the activation can fail in future.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
kernel/irq/autoprobe.c | 2 +-
kernel/irq/chip.c | 30 ++++++++++++++++++++++++------
kernel/irq/internals.h | 2 ++
kernel/irq/manage.c | 17 ++++++++++++++++-
4 files changed, 43 insertions(+), 8 deletions(-)

Index: b/kernel/irq/autoprobe.c
===================================================================
--- a/kernel/irq/autoprobe.c
+++ b/kernel/irq/autoprobe.c
@@ -53,7 +53,7 @@ unsigned long probe_irq_on(void)
if (desc->irq_data.chip->irq_set_type)
desc->irq_data.chip->irq_set_type(&desc->irq_data,
IRQ_TYPE_PROBE);
- irq_startup(desc, IRQ_NORESEND, IRQ_START_FORCE);
+ irq_activate_and_startup(desc, IRQ_NORESEND);
}
raw_spin_unlock_irq(&desc->lock);
}
Index: b/kernel/irq/chip.c
===================================================================
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -207,20 +207,19 @@ static int
* Catch code which fiddles with enable_irq() on a managed
* and potentially shutdown IRQ. Chained interrupt
* installment or irq auto probing should not happen on
- * managed irqs either. Emit a warning, break the affinity
- * and start it up as a normal interrupt.
+ * managed irqs either.
*/
if (WARN_ON_ONCE(force))
- return IRQ_STARTUP_NORMAL;
+ return IRQ_STARTUP_ABORT;
/*
* The interrupt was requested, but there is no online CPU
* in it's affinity mask. Put it into managed shutdown
* state and let the cpu hotplug mechanism start it up once
* a CPU in the mask becomes available.
*/
- irqd_set_managed_shutdown(d);
return IRQ_STARTUP_ABORT;
}
+ irq_domain_activate_irq(d);
return IRQ_STARTUP_MANAGED;
}
#else
@@ -236,7 +235,9 @@ static int __irq_startup(struct irq_desc
struct irq_data *d = irq_desc_get_irq_data(desc);
int ret = 0;

- irq_domain_activate_irq(d);
+ /* Warn if this interrupt is not activated but try nevertheless */
+ WARN_ON_ONCE(!irqd_is_activated(d));
+
if (d->chip->irq_startup) {
ret = d->chip->irq_startup(d);
irq_state_clr_disabled(desc);
@@ -269,6 +270,7 @@ int irq_startup(struct irq_desc *desc, b
irq_set_affinity_locked(d, aff, false);
break;
case IRQ_STARTUP_ABORT:
+ irqd_set_managed_shutdown(d);
return 0;
}
}
@@ -278,6 +280,22 @@ int irq_startup(struct irq_desc *desc, b
return ret;
}

+int irq_activate(struct irq_desc *desc)
+{
+ struct irq_data *d = irq_desc_get_irq_data(desc);
+
+ if (!irqd_affinity_is_managed(d))
+ irq_domain_activate_irq(d);
+ return 0;
+}
+
+void irq_activate_and_startup(struct irq_desc *desc, bool resend)
+{
+ if (WARN_ON(irq_activate(desc)))
+ return;
+ irq_startup(desc, resend, IRQ_START_FORCE);
+}
+
static void __irq_disable(struct irq_desc *desc, bool mask);

void irq_shutdown(struct irq_desc *desc)
@@ -953,7 +971,7 @@ static void
irq_settings_set_norequest(desc);
irq_settings_set_nothread(desc);
desc->action = &chained_action;
- irq_startup(desc, IRQ_RESEND, IRQ_START_FORCE);
+ irq_activate_and_startup(desc, IRQ_RESEND);
}
}

Index: b/kernel/irq/internals.h
===================================================================
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -74,6 +74,8 @@ extern void __enable_irq(struct irq_desc
#define IRQ_START_FORCE true
#define IRQ_START_COND false

+extern int irq_activate(struct irq_desc *desc);
+extern void irq_activate_and_startup(struct irq_desc *desc, bool resend);
extern int irq_startup(struct irq_desc *desc, bool resend, bool force);

extern void irq_shutdown(struct irq_desc *desc);
Index: b/kernel/irq/manage.c
===================================================================
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -519,7 +519,7 @@ void __enable_irq(struct irq_desc *desc)
* time. If it was already started up, then irq_startup()
* will invoke irq_enable() under the hood.
*/
- irq_startup(desc, IRQ_RESEND, IRQ_START_COND);
+ irq_startup(desc, IRQ_RESEND, IRQ_START_FORCE);
break;
}
default:
@@ -1325,6 +1325,21 @@ static int
goto out_unlock;
}

+ /*
+ * Activate the interrupt. That activation must happen
+ * independently of IRQ_NOAUTOEN. request_irq() can fail
+ * and the callers are supposed to handle
+ * that. enable_irq() of an interrupt requested with
+ * IRQ_NOAUTOEN is not supposed to fail. The activation
+ * keeps it in shutdown mode, it merily associates
+ * resources if necessary and if that's not possible it
+ * fails. Interrupts which are in managed shutdown mode
+ * will simply ignore that activation request.
+ */
+ ret = irq_activate(desc);
+ if (ret)
+ goto out_unlock;
+
desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
IRQS_ONESHOT | IRQS_WAITING);
irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);

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