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powernv/opal: Notifier for OPAL events 

This patch implements a notifier to receive a notification on OPAL
event mask changes. The notifier is only called as a result of an OPAL
interrupt, which will happen upon reception of FSP messages or PCI errors.
Any event mask change detected as a result of opal_poll_events() will not
result in a notifier call.

[benh: changelog]
Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Gavin Shan 2013-06-20 18:13:22 +08:00 committed by Benjamin Herrenschmidt
parent b95cd2cd44
commit 1bc98de26d
2 changed files with 73 additions and 1 deletions
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5
arch/powerpc/include/asm/opal.h
View File

@ -644,6 +644,11 @@ extern void hvc_opal_init_early(void);
extern int early_init_dt_scan_opal(unsigned long node, const char *uname,
int depth, void *data);
extern int opal_notifier_register(struct notifier_block *nb);
extern void opal_notifier_enable(void);
extern void opal_notifier_disable(void);
extern void opal_notifier_update_evt(uint64_t evt_mask, uint64_t evt_val);
extern int opal_get_chars(uint32_t vtermno, char *buf, int count);
extern int opal_put_chars(uint32_t vtermno, const char *buf, int total_len);

69
arch/powerpc/platforms/powernv/opal.c
View File

@ -15,6 +15,7 @@
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/interrupt.h>
#include <linux/notifier.h>
#include <linux/slab.h>
#include <asm/opal.h>
#include <asm/firmware.h>
@ -31,6 +32,10 @@ static DEFINE_SPINLOCK(opal_write_lock);
extern u64 opal_mc_secondary_handler[];
static unsigned int *opal_irqs;
static unsigned int opal_irq_count;
static ATOMIC_NOTIFIER_HEAD(opal_notifier_head);
static DEFINE_SPINLOCK(opal_notifier_lock);
static uint64_t last_notified_mask = 0x0ul;
static atomic_t opal_notifier_hold = ATOMIC_INIT(0);
int __init early_init_dt_scan_opal(unsigned long node,
const char *uname, int depth, void *data)
@ -95,6 +100,68 @@ static int __init opal_register_exception_handlers(void)
early_initcall(opal_register_exception_handlers);
int opal_notifier_register(struct notifier_block *nb)
{
if (!nb) {
pr_warning("%s: Invalid argument (%p)\n",
__func__, nb);
return -EINVAL;
}
atomic_notifier_chain_register(&opal_notifier_head, nb);
return 0;
}
static void opal_do_notifier(uint64_t events)
{
unsigned long flags;
uint64_t changed_mask;
if (atomic_read(&opal_notifier_hold))
return;
spin_lock_irqsave(&opal_notifier_lock, flags);
changed_mask = last_notified_mask ^ events;
last_notified_mask = events;
spin_unlock_irqrestore(&opal_notifier_lock, flags);
/*
* We feed with the event bits and changed bits for
* enough information to the callback.
*/
atomic_notifier_call_chain(&opal_notifier_head,
events, (void *)changed_mask);
}
void opal_notifier_update_evt(uint64_t evt_mask,
uint64_t evt_val)
{
unsigned long flags;
spin_lock_irqsave(&opal_notifier_lock, flags);
last_notified_mask &= ~evt_mask;
last_notified_mask |= evt_val;
spin_unlock_irqrestore(&opal_notifier_lock, flags);
}
void opal_notifier_enable(void)
{
int64_t rc;
uint64_t evt = 0;
atomic_set(&opal_notifier_hold, 0);
/* Process pending events */
rc = opal_poll_events(&evt);
if (rc == OPAL_SUCCESS && evt)
opal_do_notifier(evt);
}
void opal_notifier_disable(void)
{
atomic_set(&opal_notifier_hold, 1);
}
int opal_get_chars(uint32_t vtermno, char *buf, int count)
{
s64 len, rc;
@ -297,7 +364,7 @@ static irqreturn_t opal_interrupt(int irq, void *data)
opal_handle_interrupt(virq_to_hw(irq), &events);
/* XXX TODO: Do something with the events */
opal_do_notifier(events);
return IRQ_HANDLED;
}