Subject: [PATCH] i2c: mv64xxx: Fix locked bus when offload is selected but not used on a message

From: [email-masked] (Gregory CLEMENT)
Date: Fri, 07 Feb 2014 16:18:00 +0100

On 07/02/2014 16:09, Jason Cooper wrote:
> On Fri, Feb 07, 2014 at 11:55:54AM +0100, Gregory CLEMENT wrote:
>> Offload can be used only on regular transactions and for 1 to byte
>> transfers. In the other cases we switch back to usual work flow.
>>
>> In this case we need to call mv64xxx_i2c_prepare_for_io() as this
>> function is not used when we try to use offloading.
>>
>> This commit adds this missing call when offloading have failed in the
>> MV64XXX_I2C_ACTION_OFFLOAD_SEND_START case.
>>
>> This fix the timeout seen when the the i2c driver try to access an
>> address where the device is absent on the Armada XP bases board.
>>
>> Cc: stable at vger.kernel.org # v3.12+
>> Fixes: 930ab3d403ae (i2c: mv64xxx: Add I2C Transaction Generator support)
>>
>> Signed-off-by: Gregory CLEMENT <[email-masked]>
>> ---
>>  drivers/i2c/busses/i2c-mv64xxx.c | 9 ++++++++-
>>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> I'd like to get a few tested-by's on this before this is pushed.  We've
> had quite a bit of fixes this round :(  Please test both multi_v7 and
> mvebu defconfigs.

Well of course I have tested with multi_v7 and mvebu defconfigs, but I
think it is not my tested-by that you want! :)

An for the test we only have to test the Armada XP B0 based board, because
in the other case the offload is disable, so the code I modified never
doesn't run.

Thanks,

Gregory

> 
> Kevin, I know you're busy with a lot more than us, but if you could
> confirm that this fixes the bus hangs you reported, that would be great.
> 
> thx,
> 
> Jason.
> 
>>
>> diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c
>> index b8c5187b9ee0..a1700c62d955 100644
>> --- a/drivers/i2c/busses/i2c-mv64xxx.c
>> +++ b/drivers/i2c/busses/i2c-mv64xxx.c
>> @@ -461,8 +461,15 @@ mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data)
>>  	case MV64XXX_I2C_ACTION_OFFLOAD_SEND_START:
>>  		if (!mv64xxx_i2c_offload_msg(drv_data))
>>  			break;
>> -		else
>> +		else {
>>  			drv_data->action = MV64XXX_I2C_ACTION_SEND_START;
>> +			/*
>> +			 * Switch to the standard path, so we finally need to
>> +			 * prepare the io that have not been done in
>> +			 * mv64xxx_i2c_execute_msg
>> +			 */
>> +			mv64xxx_i2c_prepare_for_io(drv_data, drv_data->msgs);
>> +		}
>>  		/* FALLTHRU */
>>  	case MV64XXX_I2C_ACTION_SEND_START:
>>  		writel(drv_data->cntl_bits | MV64XXX_I2C_REG_CONTROL_START,
>> -- 
>> 1.8.1.2
>>

-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com