On some environments (prototype machines, some simulators, etc...)
there is no functional interrupt source to signal completion, so
we rely on the fairly slow OPAL heartbeat.
In a number of cases, the calls complete very quickly or even
immediately. We've observed that it helps a lot to wakeup the OPAL
heartbeat thread before waiting for event in those cases, it will
call OPAL immediately to collect completions for anything that
finished fast enough.
Signed-off-by: Benjamin Herrenschmidt <b...@kernel.crashing.org>
---
arch/powerpc/include/asm/opal.h | 2 ++
arch/powerpc/platforms/powernv/opal-async.c | 5 +++++
arch/powerpc/platforms/powernv/opal.c | 12 ++++++++++--
3 files changed, 17 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index 6135816..0c76bc0 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -277,6 +277,8 @@ extern int opal_error_code(int rc);
ssize_t opal_msglog_copy(char *to, loff_t pos, size_t count);
+void opal_wake_poller(void);
+
#endif /* __ASSEMBLY__ */
#endif /* _ASM_POWERPC_OPAL_H */
diff --git a/arch/powerpc/platforms/powernv/opal-async.c
b/arch/powerpc/platforms/powernv/opal-async.c
index bdc8c0c..83bebee 100644
--- a/arch/powerpc/platforms/powernv/opal-async.c
+++ b/arch/powerpc/platforms/powernv/opal-async.c
@@ -117,6 +117,11 @@ int opal_async_wait_response(uint64_t token, struct
opal_msg *msg)
return -EINVAL;
}
+ /* Wakeup the poller before we wait for events to speed things
+ * up on platforms or simulators where the interrupts aren't
+ * functional.
+ */
+ opal_wake_poller();
wait_event(opal_async_wait, test_bit(token, opal_async_complete_map));
memcpy(msg, &opal_async_responses[token], sizeof(*msg));
diff --git a/arch/powerpc/platforms/powernv/opal.c
b/arch/powerpc/platforms/powernv/opal.c
index 802f3b7..7f13302 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -55,6 +55,7 @@ struct device_node *opal_node;
static DEFINE_SPINLOCK(opal_write_lock);
static struct atomic_notifier_head opal_msg_notifier_head[OPAL_MSG_TYPE_MAX];
static uint32_t opal_heartbeat;
+static struct task_struct *kopald_tsk;
void opal_configure_cores(void)
{
@@ -650,6 +651,7 @@ static void opal_i2c_create_devs(void)
static int kopald(void *unused)
{
+ unsigned long timeout = msecs_to_jiffies(opal_heartbeat) + 1;
__be64 events;
set_freezable();
@@ -657,12 +659,18 @@ static int kopald(void *unused)
try_to_freeze();
opal_poll_events(&events);
opal_handle_events(be64_to_cpu(events));
- msleep_interruptible(opal_heartbeat);
+ schedule_timeout_interruptible(timeout);
} while (!kthread_should_stop());
return 0;
}
+void opal_wake_poller(void)
+{
+ if (kopald_tsk)
+ wake_up_process(kopald_tsk);
+}
+
static void opal_init_heartbeat(void)
{
/* Old firwmware, we assume the HVC heartbeat is sufficient */
@@ -671,7 +679,7 @@ static void opal_init_heartbeat(void)
opal_heartbeat = 0;
if (opal_heartbeat)
- kthread_run(kopald, NULL, "kopald");
+ kopald_tsk = kthread_run(kopald, NULL, "kopald");
}
static int __init opal_init(void)
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