This patch originated from the discussion with Dmitry in the below thread:
https://lore.kernel.org/linux-input/20210102042902.41664-1-song.bao....@hisilicon.com/
there are many drivers which don't want interrupts enabled automatically
due to request_irq().
So they are handling this issue by either way of the below two:
(1)
irq_set_status_flags(irq, IRQ_NOAUTOEN);
request_irq(dev, irq...);
(2)
request_irq(dev, irq...);
disable_irq(irq);
The code in the second way is silly and unsafe. In the small time gap
between request_irq and disable_irq, interrupts can still come.
The code in the first way is safe though we might be able to do it in
the generic irq code.
I guess Dmitry also prefers genirq handles this as he said
"What I would like to see is to allow passing something like IRQF_DISABLED
to request_irq() so that we would not need neither irq_set_status_flags()
nor disable_irq()" in the original email thread.
If this one is accepted, hundreds of drivers with this problem will be
handled afterwards.
Cc: Dmitry Torokhov <dmitry.torok...@gmail.com>
Signed-off-by: Barry Song <song.bao....@hisilicon.com>
---
include/linux/interrupt.h | 3 +++
kernel/irq/manage.c | 3 +++
kernel/irq/settings.h | 10 ++++++++++
3 files changed, 16 insertions(+)
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index bb8ff9083e7d..0f22d277078c 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -61,6 +61,8 @@
* interrupt handler after suspending interrupts. For system
* wakeup devices users need to implement wakeup detection in
* their interrupt handlers.
+ * IRQF_NO_AUTOEN - Don't enable IRQ automatically when users request it. Users
+ * will enable it explicitly by enable_irq() later.
*/
#define IRQF_SHARED 0x00000080
#define IRQF_PROBE_SHARED 0x00000100
@@ -74,6 +76,7 @@
#define IRQF_NO_THREAD 0x00010000
#define IRQF_EARLY_RESUME 0x00020000
#define IRQF_COND_SUSPEND 0x00040000
+#define IRQF_NO_AUTOEN 0x00080000
#define IRQF_TIMER (__IRQF_TIMER | IRQF_NO_SUSPEND |
IRQF_NO_THREAD)
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index ab8567f32501..364e8b47d9ba 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1693,6 +1693,9 @@ __setup_irq(unsigned int irq, struct irq_desc *desc,
struct irqaction *new)
irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
}
+ if (new->flags & IRQF_NO_AUTOEN)
+ irq_settings_set_noautoen(desc);
+
if (irq_settings_can_autoenable(desc)) {
irq_startup(desc, IRQ_RESEND, IRQ_START_COND);
} else {
diff --git a/kernel/irq/settings.h b/kernel/irq/settings.h
index 403378b9947b..a28958a9c548 100644
--- a/kernel/irq/settings.h
+++ b/kernel/irq/settings.h
@@ -145,6 +145,16 @@ static inline bool irq_settings_can_move_pcntxt(struct
irq_desc *desc)
return desc->status_use_accessors & _IRQ_MOVE_PCNTXT;
}
+static inline void irq_settings_clr_noautoen(struct irq_desc *desc)
+{
+ desc->status_use_accessors &= ~_IRQ_NOAUTOEN;
+}
+
+static inline void irq_settings_set_noautoen(struct irq_desc *desc)
+{
+ desc->status_use_accessors |= _IRQ_NOAUTOEN;
+}
+
static inline bool irq_settings_can_autoenable(struct irq_desc *desc)
{
return !(desc->status_use_accessors & _IRQ_NOAUTOEN);
--
2.25.1
