This patch originated from the discussion with Dmitry in the below thread: https://lore.kernel.org/linux-input/20210102042902.41664-1-song.bao.hua@hisi... 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.torokhov@gmail.com Signed-off-by: Barry Song song.bao.hua@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);