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Commit 3b807033 authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michael Ellerman
Browse files

powerpc/powernv: Fix OPAL NVRAM driver OPAL_BUSY loops 



The OPAL NVRAM driver does not sleep in case it gets OPAL_BUSY or
OPAL_BUSY_EVENT from firmware, which causes large scheduling
latencies, and various lockup errors to trigger (again, BMC reboot
can cause it).

Fix this by converting it to the standard form OPAL_BUSY loop that
sleeps.

Fixes: 628daa8d ("powerpc/powernv: Add RTC and NVRAM support plus RTAS fallbacks")
Depends-on: 34dd25de ("powerpc/powernv: define a standard delay for OPAL_BUSY type retry loops")
Cc: stable@vger.kernel.org # v3.2+
Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 34dd25de

arch/powerpc/platforms/powernv/opal-nvram.c

+6 −1
Original line number Original line Diff line number Diff line
@@ -11,6 +11,7 @@ 




#define DEBUG

#define DEBUG





#include <linux/delay.h>

#include <linux/kernel.h>

#include <linux/kernel.h>

#include <linux/init.h>

#include <linux/init.h>

#include <linux/of.h>

#include <linux/of.h>
@@ -56,8 +57,12 @@ static ssize_t opal_nvram_write(char *buf, size_t count, loff_t *index) 




	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {

	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {

		rc = opal_write_nvram(__pa(buf), count, off);

		rc = opal_write_nvram(__pa(buf), count, off);

		if (rc == OPAL_BUSY_EVENT)

		if (rc == OPAL_BUSY_EVENT) {

			msleep(OPAL_BUSY_DELAY_MS);

			opal_poll_events(NULL);

			opal_poll_events(NULL);

		} else if (rc == OPAL_BUSY) {

			msleep(OPAL_BUSY_DELAY_MS);

		}

	}

	}





	if (rc)

	if (rc)