From 843da234cfc0e7014f9e2da82786a485e0820665 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Thu, 13 Mar 2014 15:32:05 +0100
Subject: [PATCH] irq: Add a new IRQCHIP_EOI_THREADED flag
This flag must be used in combination with handle_fasteoi_irq, when set
handle_fasteoi_irq will delay the calling of chip->irq_eoi until the threaded
handler has run.
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
include/linux/irq.h | 3 +++
kernel/irq/chip.c | 48 ++++++++++++++++++++++++++++++++++++++++--------
kernel/irq/internals.h | 1 +
kernel/irq/manage.c | 2 +-
4 files changed, 45 insertions(+), 9 deletions(-)
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -349,6 +349,8 @@ struct irq_chip {
* 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
*/
enum {
IRQCHIP_SET_TYPE_MASKED = (1 << 0),
@@ -357,6 +359,7 @@ enum {
IRQCHIP_ONOFFLINE_ENABLED = (1 << 3),
IRQCHIP_SKIP_SET_WAKE = (1 << 4),
IRQCHIP_ONESHOT_SAFE = (1 << 5),
+ IRQCHIP_EOI_THREADED = (1 << 6),
};
/* This include will go away once we isolated irq_desc usage to core code */
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -281,6 +281,19 @@ void unmask_irq(struct irq_desc *desc)
}
}
+void unmask_threaded_irq(struct irq_desc *desc)
+{
+ struct irq_chip *chip = desc->irq_data.chip;
+
+ if (chip->flags & IRQCHIP_EOI_THREADED)
+ chip->irq_eoi(&desc->irq_data);
+
+ if (chip->irq_unmask) {
+ chip->irq_unmask(&desc->irq_data);
+ irq_state_clr_masked(desc);
+ }
+}
+
/*
* handle_nested_irq - Handle a nested irq from a irq thread
* @irq: the interrupt number
@@ -435,6 +448,27 @@ static inline void preflow_handler(struc
static inline void preflow_handler(struct irq_desc *desc) { }
#endif
+static void cond_unmask_eoi_irq(struct irq_desc *desc, struct irq_chip *chip)
+{
+ if (!(desc->istate & IRQS_ONESHOT)) {
+ chip->irq_eoi(&desc->irq_data);
+ return;
+ }
+ /*
+ * We need to unmask in the following cases:
+ * - Oneshot irq which did not wake the thread (caused by a
+ * spurious interrupt or a primary handler handling it
+ * completely).
+ */
+ if (!irqd_irq_disabled(&desc->irq_data) &&
+ irqd_irq_masked(&desc->irq_data) && !desc->threads_oneshot) {
+ chip->irq_eoi(&desc->irq_data);
+ unmask_irq(desc);
+ } else if (!(chip->flags & IRQCHIP_EOI_THREADED)) {
+ chip->irq_eoi(&desc->irq_data);
+ }
+}
+
/**
* handle_fasteoi_irq - irq handler for transparent controllers
* @irq: the interrupt number
@@ -448,6 +482,8 @@ static inline void preflow_handler(struc
void
handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
{
+ struct irq_chip *chip = desc->irq_data.chip;
+
raw_spin_lock(&desc->lock);
if (unlikely(irqd_irq_inprogress(&desc->irq_data)))
@@ -473,18 +509,14 @@ handle_fasteoi_irq(unsigned int irq, str
preflow_handler(desc);
handle_irq_event(desc);
- if (desc->istate & IRQS_ONESHOT)
- cond_unmask_irq(desc);
+ cond_unmask_eoi_irq(desc, chip);
-out_eoi:
- desc->irq_data.chip->irq_eoi(&desc->irq_data);
-out_unlock:
raw_spin_unlock(&desc->lock);
return;
out:
- if (!(desc->irq_data.chip->flags & IRQCHIP_EOI_IF_HANDLED))
- goto out_eoi;
- goto out_unlock;
+ if (!(chip->flags & IRQCHIP_EOI_IF_HANDLED))
+ chip->irq_eoi(&desc->irq_data);
+ raw_spin_unlock(&desc->lock);
}
/**
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -73,6 +73,7 @@ extern void irq_percpu_enable(struct irq
extern void irq_percpu_disable(struct irq_desc *desc, unsigned int cpu);
extern void mask_irq(struct irq_desc *desc);
extern void unmask_irq(struct irq_desc *desc);
+extern void unmask_threaded_irq(struct irq_desc *desc);
extern void init_kstat_irqs(struct irq_desc *desc, int node, int nr);
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -713,7 +713,7 @@ again:
if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
irqd_irq_masked(&desc->irq_data))
- unmask_irq(desc);
+ unmask_threaded_irq(desc);
out_unlock:
raw_spin_unlock_irq(&desc->lock);
--- a/drivers/irqchip/irq-sun4i.c
+++ b/drivers/irqchip/irq-sun4i.c
@@ -41,13 +41,11 @@ static asmlinkage void __exception_irq_e
static void sun4i_irq_ack(struct irq_data *irqd)
{
unsigned int irq = irqd_to_hwirq(irqd);
- unsigned int irq_off = irq % 32;
- int reg = irq / 32;
- u32 val;
- val = readl(sun4i_irq_base + SUN4I_IRQ_PENDING_REG(reg));
- writel(val | (1 << irq_off),
- sun4i_irq_base + SUN4I_IRQ_PENDING_REG(reg));
+ if (irq != 0)
+ return; /* Only IRQ 0 / the ENMI needs to be acked */
+
+ writel(BIT(0), sun4i_irq_base + SUN4I_IRQ_PENDING_REG(0));
}
static void sun4i_irq_mask(struct irq_data *irqd)
@@ -76,16 +74,16 @@ static void sun4i_irq_unmask(struct irq_
static struct irq_chip sun4i_irq_chip = {
.name = "sun4i_irq",
- .irq_ack = sun4i_irq_ack,
+ .irq_eoi = sun4i_irq_ack,
.irq_mask = sun4i_irq_mask,
.irq_unmask = sun4i_irq_unmask,
+ .flags = IRQCHIP_EOI_THREADED | IRQCHIP_EOI_IF_HANDLED,
};
static int sun4i_irq_map(struct irq_domain *d, unsigned int virq,
irq_hw_number_t hw)
{
- irq_set_chip_and_handler(virq, &sun4i_irq_chip,
- handle_level_irq);
+ irq_set_chip_and_handler(virq, &sun4i_irq_chip, handle_fasteoi_irq);
set_irq_flags(virq, IRQF_VALID | IRQF_PROBE);
return 0;
@@ -109,7 +107,7 @@ static int __init sun4i_of_init(struct d
writel(0, sun4i_irq_base + SUN4I_IRQ_ENABLE_REG(1));
writel(0, sun4i_irq_base + SUN4I_IRQ_ENABLE_REG(2));
- /* Mask all the interrupts */
+ /* Unmask all the interrupts, ENABLE_REG(x) is used for masking */
writel(0, sun4i_irq_base + SUN4I_IRQ_MASK_REG(0));
writel(0, sun4i_irq_base + SUN4I_IRQ_MASK_REG(1));
writel(0, sun4i_irq_base + SUN4I_IRQ_MASK_REG(2));
@@ -140,10 +138,24 @@ static asmlinkage void __exception_irq_e
{
u32 irq, hwirq;
+ /*
+ * hwirq == 0 can mean one of 3 things:
+ * 1) no more irqs pending
+ * 2) irq 0 pending
+ * 3) spurious irq
+ * So if we immediately get a reading of 0, check the irq-pending reg
+ * to differentiate between 2 and 3. We only do this once to avoid
+ * the extra check in the common case of 1 hapening after having
+ * read the vector-reg once.
+ */
hwirq = readl(sun4i_irq_base + SUN4I_IRQ_VECTOR_REG) >> 2;
- while (hwirq != 0) {
+ if (hwirq == 0 &&
+ !(readl(sun4i_irq_base + SUN4I_IRQ_PENDING_REG(0)) & BIT(0)))
+ return;
+
+ do {
irq = irq_find_mapping(sun4i_irq_domain, hwirq);
handle_IRQ(irq, regs);
hwirq = readl(sun4i_irq_base + SUN4I_IRQ_VECTOR_REG) >> 2;
- }
+ } while (hwirq != 0);
}