Messages in this thread Patch in this message | | | From | Guenter Roeck <> | Subject | [PATCH] mfd: kempld-core: Fix potential hang-up during boot | Date | Thu, 20 Mar 2014 08:12:28 -0700 |
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On PXT and COMe-cPC2 boards it is observed that the hardware mutex is acquired but not being released during initialization. This can result in a hang-up during boot if the driver is built into the kernel.
Releasing the mutex twice if it was acquired fixes the problem. Subsequent request/release cycles work as expected, so the fix is only needed during initialization.
Reviewed-by: Michael Brunner <michael.brunner@kontron.com> Tested-by: Michael Brunner <michael.brunner@kontron.com> Signed-off-by: Guenter Roeck <linux@roeck-us.net> --- drivers/mfd/kempld-core.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/mfd/kempld-core.c b/drivers/mfd/kempld-core.c index d3e2327..38917a8 100644 --- a/drivers/mfd/kempld-core.c +++ b/drivers/mfd/kempld-core.c @@ -322,9 +322,12 @@ static int kempld_detect_device(struct kempld_device_data *pld) return -ENODEV; } - /* Release hardware mutex if aquired */ - if (!(index_reg & KEMPLD_MUTEX_KEY)) + /* Release hardware mutex if acquired */ + if (!(index_reg & KEMPLD_MUTEX_KEY)) { iowrite8(KEMPLD_MUTEX_KEY, pld->io_index); + /* PXT and COMe-cPC2 boards may require a second release */ + iowrite8(KEMPLD_MUTEX_KEY, pld->io_index); + } mutex_unlock(&pld->lock); -- 1.7.9.7
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