diff options
author | Marc Zyngier <marc.zyngier@arm.com> | 2015-03-18 11:01:22 +0000 |
---|---|---|
committer | Thomas Gleixner <tglx@linutronix.de> | 2015-04-08 23:28:28 +0200 |
commit | 1b7047edfcfb257f69e306c9afbab150cb987717 (patch) | |
tree | 68b2383acee6ce6a58900507e797e9c6178e4a5b | |
parent | fe0c52fc003bc046380e52fe6799c96d770770cc (diff) |
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 <marc.zyngier@arm.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Tested-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Phong Vo <pvo@apm.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Tin Huynh <tnhuynh@apm.com>
Cc: Y Vo <yvo@apm.com>
Cc: Toan Le <toanle@apm.com>
Cc: Bjorn Andersson <bjorn@kryo.se>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Link: http://lkml.kernel.org/r/1426676484-21812-2-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-rw-r--r-- | include/linux/interrupt.h | 14 | ||||
-rw-r--r-- | include/linux/irq.h | 6 | ||||
-rw-r--r-- | kernel/irq/manage.c | 91 |
3 files changed, 111 insertions, 0 deletions
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; }; diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index c0a1100d911f..e68932bb308e 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -1798,3 +1798,94 @@ int request_percpu_irq(unsigned int irq, irq_handler_t handler, return retval; } + +/** + * irq_get_irqchip_state - returns the irqchip state of a interrupt. + * @irq: Interrupt line that is forwarded to a VM + * @which: One of IRQCHIP_STATE_* the caller wants to know about + * @state: a pointer to a boolean where the state is to be storeed + * + * This call snapshots the internal irqchip state of an + * interrupt, returning into @state the bit corresponding to + * stage @which + * + * This function should be called with preemption disabled if the + * interrupt controller has per-cpu registers. + */ +int irq_get_irqchip_state(unsigned int irq, enum irqchip_irq_state which, + bool *state) +{ + struct irq_desc *desc; + struct irq_data *data; + struct irq_chip *chip; + unsigned long flags; + int err = -EINVAL; + + desc = irq_get_desc_buslock(irq, &flags, 0); + if (!desc) + return err; + + data = irq_desc_get_irq_data(desc); + + do { + chip = irq_data_get_irq_chip(data); + if (chip->irq_get_irqchip_state) + break; +#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY + data = data->parent_data; +#else + data = NULL; +#endif + } while (data); + + if (data) + err = chip->irq_get_irqchip_state(data, which, state); + + irq_put_desc_busunlock(desc, flags); + return err; +} + +/** + * irq_set_irqchip_state - set the state of a forwarded interrupt. + * @irq: Interrupt line that is forwarded to a VM + * @which: State to be restored (one of IRQCHIP_STATE_*) + * @val: Value corresponding to @which + * + * This call sets the internal irqchip state of an interrupt, + * depending on the value of @which. + * + * This function should be called with preemption disabled if the + * interrupt controller has per-cpu registers. + */ +int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which, + bool val) +{ + struct irq_desc *desc; + struct irq_data *data; + struct irq_chip *chip; + unsigned long flags; + int err = -EINVAL; + + desc = irq_get_desc_buslock(irq, &flags, 0); + if (!desc) + return err; + + data = irq_desc_get_irq_data(desc); + + do { + chip = irq_data_get_irq_chip(data); + if (chip->irq_set_irqchip_state) + break; +#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY + data = data->parent_data; +#else + data = NULL; +#endif + } while (data); + + if (data) + err = chip->irq_set_irqchip_state(data, which, val); + + irq_put_desc_busunlock(desc, flags); + return err; +} |