diff options
| author | Guenter Roeck <linux@roeck-us.net> | 2014-03-20 08:12:28 -0700 |
|---|---|---|
| committer | Lee Jones <lee.jones@linaro.org> | 2014-03-20 15:58:25 +0000 |
| commit | 204747c970c0d568721c76ab8a57dde0e5dcf0d5 (patch) | |
| tree | 2235bb09163819c324a8bbb1473fcdd394c37779 /drivers/mfd/kempld-core.c | |
| parent | 5a78401623740c892868d5929b33f5cda8fe819e (diff) | |
| download | lwn-204747c970c0d568721c76ab8a57dde0e5dcf0d5.tar.gz lwn-204747c970c0d568721c76ab8a57dde0e5dcf0d5.zip | |
mfd: kempld-core: Fix potential hang-up during boot
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.
Cc: <stable@vger.kernel.org>
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>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Diffstat (limited to 'drivers/mfd/kempld-core.c')
| -rw-r--r-- | drivers/mfd/kempld-core.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/drivers/mfd/kempld-core.c b/drivers/mfd/kempld-core.c index 20a6afcfb36c..07692604e119 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); |