From 1b7047edfcfb257f69e306c9afbab150cb987717 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Wed, 18 Mar 2015 11:01:22 +0000 Subject: genirq: Allow the irqchip state of an IRQ to be save/restored There is a number of cases where a kernel subsystem may want to introspect the state of an interrupt at the irqchip level: - When a peripheral is shared between virtual machines, its interrupt state becomes part of the guest's state, and must be switched accordingly. KVM on arm/arm64 requires this for its guest-visible timer - Some GPIO controllers seem to require peeking into the interrupt controller they are connected to to report their internal state This seem to be a pattern that is common enough for the core code to try and support this without too many horrible hacks. Introduce a pair of accessors (irq_get_irqchip_state/irq_set_irqchip_state) to retrieve the bits that can be of interest to another subsystem: pending, active, and masked. - irq_get_irqchip_state returns the state of the interrupt according to a parameter set to IRQCHIP_STATE_PENDING, IRQCHIP_STATE_ACTIVE, IRQCHIP_STATE_MASKED or IRQCHIP_STATE_LINE_LEVEL. - irq_set_irqchip_state similarly sets the state of the interrupt. Signed-off-by: Marc Zyngier Reviewed-by: Bjorn Andersson Tested-by: Bjorn Andersson Cc: linux-arm-kernel@lists.infradead.org Cc: Abhijeet Dharmapurikar Cc: Stephen Boyd Cc: Phong Vo Cc: Linus Walleij Cc: Tin Huynh Cc: Y Vo Cc: Toan Le Cc: Bjorn Andersson Cc: Jason Cooper Cc: Arnd Bergmann Link: http://lkml.kernel.org/r/1426676484-21812-2-git-send-email-marc.zyngier@arm.com Signed-off-by: Thomas Gleixner --- include/linux/interrupt.h | 14 ++++++++++++++ include/linux/irq.h | 6 ++++++ 2 files changed, 20 insertions(+) (limited to 'include') diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index 150dde04cf4f..950ae4501826 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -361,6 +361,20 @@ static inline int disable_irq_wake(unsigned int irq) return irq_set_irq_wake(irq, 0); } +/* + * irq_get_irqchip_state/irq_set_irqchip_state specific flags + */ +enum irqchip_irq_state { + IRQCHIP_STATE_PENDING, /* Is interrupt pending? */ + IRQCHIP_STATE_ACTIVE, /* Is interrupt in progress? */ + IRQCHIP_STATE_MASKED, /* Is interrupt masked? */ + IRQCHIP_STATE_LINE_LEVEL, /* Is IRQ line high? */ +}; + +extern int irq_get_irqchip_state(unsigned int irq, enum irqchip_irq_state which, + bool *state); +extern int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which, + bool state); #ifdef CONFIG_IRQ_FORCED_THREADING extern bool force_irqthreads; diff --git a/include/linux/irq.h b/include/linux/irq.h index d09ec7a1243e..77dd2e7f93f4 100644 --- a/include/linux/irq.h +++ b/include/linux/irq.h @@ -30,6 +30,7 @@ struct seq_file; struct module; struct msi_msg; +enum irqchip_irq_state; /* * IRQ line status. @@ -324,6 +325,8 @@ static inline irq_hw_number_t irqd_to_hwirq(struct irq_data *d) * irq_request_resources * @irq_compose_msi_msg: optional to compose message content for MSI * @irq_write_msi_msg: optional to write message content for MSI + * @irq_get_irqchip_state: return the internal state of an interrupt + * @irq_set_irqchip_state: set the internal state of a interrupt * @flags: chip specific flags */ struct irq_chip { @@ -363,6 +366,9 @@ struct irq_chip { void (*irq_compose_msi_msg)(struct irq_data *data, struct msi_msg *msg); void (*irq_write_msi_msg)(struct irq_data *data, struct msi_msg *msg); + int (*irq_get_irqchip_state)(struct irq_data *data, enum irqchip_irq_state which, bool *state); + int (*irq_set_irqchip_state)(struct irq_data *data, enum irqchip_irq_state which, bool state); + unsigned long flags; }; -- cgit v1.2.3