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Subject[PATCH 04/15] powerpc/powernv: opal-kmsg use flush fallback from console code
Date
Use the more refined and tested event polling loop from opal_put_chars
as the fallback console flush in the opal-kmsg path. This loop is used
by the console driver today, whereas the opal-kmsg fallback is not
likely to have been used for years.

Use WARN_ONCE rather than a printk when the fallback is invoked to
prepare for moving the console flush into a common function.

Reviewed-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/platforms/powernv/opal-kmsg.c | 15 ++++++---------
1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/opal-kmsg.c b/arch/powerpc/platforms/powernv/opal-kmsg.c
index f8f41ccce75f..fd2bbf4fd6dc 100644
--- a/arch/powerpc/platforms/powernv/opal-kmsg.c
+++ b/arch/powerpc/platforms/powernv/opal-kmsg.c
@@ -51,20 +51,17 @@ static void force_opal_console_flush(struct kmsg_dumper *dumper,
} while (rc == OPAL_PARTIAL); /* More to flush */

} else {
- int i;
+ __be64 evt;

+ WARN_ONCE(1, "opal: OPAL_CONSOLE_FLUSH missing.\n");
/*
* If OPAL_CONSOLE_FLUSH is not implemented in the firmware,
* the console can still be flushed by calling the polling
- * function enough times to flush the buffer. We don't know
- * how much output still needs to be flushed, but we can be
- * generous since the kernel is in panic and doesn't need
- * to do much else.
+ * function while it has OPAL_EVENT_CONSOLE_OUTPUT events.
*/
- printk(KERN_NOTICE "opal: OPAL_CONSOLE_FLUSH missing.\n");
- for (i = 0; i < 1024; i++) {
- opal_poll_events(NULL);
- }
+ do {
+ opal_poll_events(&evt);
+ } while (be64_to_cpu(evt) & OPAL_EVENT_CONSOLE_OUTPUT);
}
}

--
2.17.0
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