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

[Jason Cooper]

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 <gregory.clement at free-electrons.com>
> ---
>  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.

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
>