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genirq: Provide irq_request/release_resources chip callbacks 

For certain irq types, e.g. gpios, it's necessary to request resources
before starting up the irq.

This might fail so we cannot use the irq_startup() callback because we
might call the irq_set_type() callback before that which does not make
sense when the resource is not available. Calling irq_startup() before
irq_set_type() can lead to spurious interrupts which is not desired
either.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jean-Jacques Hiblot <jjhiblot@traphandler.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org 
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1403080857160.18573@ionos.tec.linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
hifive-unleashed-5.1
Thomas Gleixner 2014-03-08 08:59:58 +01:00
parent fa389e2202
commit c1bacbae81
2 changed files with 33 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
include/linux/irq.h
View File

@ -303,6 +303,10 @@ static inline irq_hw_number_t irqd_to_hwirq(struct irq_data *d)
* @irq_pm_shutdown: function called from core code on shutdown once per chip
* @irq_calc_mask: Optional function to set irq_data.mask for special cases
* @irq_print_chip: optional to print special chip info in show_interrupts
* @irq_request_resources: optional to request resources before calling
* any other callback related to this irq
* @irq_release_resources: optional to release resources acquired with
* irq_request_resources
* @flags: chip specific flags
*/
struct irq_chip {
@ -336,6 +340,8 @@ struct irq_chip {
void (*irq_calc_mask)(struct irq_data *data);
void (*irq_print_chip)(struct irq_data *data, struct seq_file *p);
int (*irq_request_resources)(struct irq_data *data);
void (*irq_release_resources)(struct irq_data *data);
unsigned long flags;
};

28
kernel/irq/manage.c
View File

@ -896,6 +896,23 @@ static void irq_setup_forced_threading(struct irqaction *new)
}
}
static int irq_request_resources(struct irq_desc *desc)
{
struct irq_data *d = &desc->irq_data;
struct irq_chip *c = d->chip;
return c->irq_request_resources ? c->irq_request_resources(d) : 0;
}
static void irq_release_resources(struct irq_desc *desc)
{
struct irq_data *d = &desc->irq_data;
struct irq_chip *c = d->chip;
if (c->irq_release_resources)
c->irq_release_resources(d);
}
/*
* Internal function to register an irqaction - typically used to
* allocate special interrupts that are part of the architecture.
@ -1091,6 +1108,13 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
}
if (!shared) {
ret = irq_request_resources(desc);
if (ret) {
pr_err("Failed to request resources for %s (irq %d) on irqchip %s\n",
new->name, irq, desc->irq_data.chip->name);
goto out_mask;
}
init_waitqueue_head(&desc->wait_for_threads);
/* Setup the type (level, edge polarity) if configured: */
@ -1261,8 +1285,10 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
*action_ptr = action->next;
/* If this was the last handler, shut down the IRQ line: */
if (!desc->action)
if (!desc->action) {
irq_shutdown(desc);
irq_release_resources(desc);
}
#ifdef CONFIG_SMP
/* make sure affinity_hint is cleaned up */