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| author | Du, Wenkai <wenkai.du@intel.com> | 2014-04-10 23:03:19 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-06-07 13:25:39 -0700 |
| commit | a6b6cde1481125b886f726756a3364be0fb9f93e (patch) | |
| tree | 058f95b5bc144b188a516f69f4ac781c729e258d /drivers | |
| parent | 670a6ed522e0fa814d74547cb95fbc4854660474 (diff) | |
| download | linux-3.10-a6b6cde1481125b886f726756a3364be0fb9f93e.tar.gz linux-3.10-a6b6cde1481125b886f726756a3364be0fb9f93e.tar.bz2 linux-3.10-a6b6cde1481125b886f726756a3364be0fb9f93e.zip | |
i2c: designware: Mask all interrupts during i2c controller enable
commit 47bb27e78867997040a228328f2a631c3c7f2c82 upstream.
There have been "i2c_designware 80860F41:00: controller timed out" errors
on a number of Baytrail platforms. The issue is caused by incorrect value in
Interrupt Mask Register (DW_IC_INTR_MASK) when i2c core is being enabled.
This causes call to __i2c_dw_enable() to immediately start the transfer which
leads to timeout. There are 3 failure modes observed:
1. Failure in S0 to S3 resume path
The default value after reset for DW_IC_INTR_MASK is 0x8ff. When we start
the first transaction after resuming from system sleep, TX_EMPTY interrupt
is already unmasked because of the hardware default.
2. Failure in normal operational path
This failure happens rarely and is hard to reproduce. Debug trace showed that
DW_IC_INTR_MASK had value of 0x254 when failure occurred, which meant
TX_EMPTY was unmasked.
3. Failure in S3 to S0 suspend path
This failure also happens rarely and is hard to reproduce. Adding debug trace
that read DW_IC_INTR_MASK made this failure not reproducible. But from ISR
call trace we could conclude TX_EMPTY was unmasked when problem occurred.
The patch masks all interrupts before the controller is enabled to resolve the
faulty DW_IC_INTR_MASK conditions.
Signed-off-by: Wenkai Du <wenkai.du@intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
[wsa: improved the comment and removed typo in commit msg]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/i2c/busses/i2c-designware-core.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c index c41ca6354fc..f24a7385260 100644 --- a/drivers/i2c/busses/i2c-designware-core.c +++ b/drivers/i2c/busses/i2c-designware-core.c @@ -380,6 +380,9 @@ static void i2c_dw_xfer_init(struct dw_i2c_dev *dev) ic_con &= ~DW_IC_CON_10BITADDR_MASTER; dw_writel(dev, ic_con, DW_IC_CON); + /* enforce disabled interrupts (due to HW issues) */ + i2c_dw_disable_int(dev); + /* Enable the adapter */ __i2c_dw_enable(dev, true); |