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powerpc/powernv: opal-kmsg use flush fallback from console code 

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>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Nicholas Piggin 2018-05-01 00:55:47 +10:00 committed by Michael Ellerman
parent 3a80bfc7ea
commit e00da0f2db
1 changed files with 6 additions and 9 deletions
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15
arch/powerpc/platforms/powernv/opal-kmsg.c
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@ -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);
}
}