On 21 February 2018 at 11:11, Leif Lindholm <[email protected]> wrote:
> On Wed, Feb 21, 2018 at 11:04:21AM +0000, Ard Biesheuvel wrote:
>> Currently, SynQuacerI2cStartRequest() increases the TPL to TPL_HIGH_LEVEL
>> while accessing the I2C controller hardware, but fails to restore the TPL
>> to the original level if the call to SynQuacerI2cMasterStart() fails, and
>> returns right away. Given the TPL_HIGH_LEVEL implies that interrupts are
>> disabled, this results in a complete system hang. So instead, break out
>> of the loop, so that the TPL restore will occur before leaving the
>> function.
>>
>> Note that this will result in the bus control bits to be de-asserted in
>> case of a failure to send the START condition, which is an appropriate
>> cleanup action to take after SynQuacerI2cMasterStart() fails.
>>
>> Contributed-under: TianoCore Contribution Agreement 1.1
>> Signed-off-by: Ard Biesheuvel <[email protected]>
>
> Reviewed-by: Leif Lindholm <[email protected]>
>
Thanks
Pushed as 33d1b85bae27
>> ---
>> v2: clarify comment and commit log to explain that releasing the bus controls
>> is an appropriate action for this failure mode
>>
>> Silicon/Socionext/SynQuacer/Drivers/SynQuacerI2cDxe/SynQuacerI2cDxe.c | 4
>> ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git
>> a/Silicon/Socionext/SynQuacer/Drivers/SynQuacerI2cDxe/SynQuacerI2cDxe.c
>> b/Silicon/Socionext/SynQuacer/Drivers/SynQuacerI2cDxe/SynQuacerI2cDxe.c
>> index 46c512a20151..5e70f9d921c3 100644
>> --- a/Silicon/Socionext/SynQuacer/Drivers/SynQuacerI2cDxe/SynQuacerI2cDxe.c
>> +++ b/Silicon/Socionext/SynQuacer/Drivers/SynQuacerI2cDxe/SynQuacerI2cDxe.c
>> @@ -324,7 +324,7 @@ SynQuacerI2cStartRequest (
>>
>> Status = SynQuacerI2cMasterStart (I2c, SlaveAddress, Op);
>> if (EFI_ERROR (Status)) {
>> - return Status;
>> + break;
>> }
>>
>> Status = WaitForInterrupt (I2c);
>> @@ -397,7 +397,7 @@ SynQuacerI2cStartRequest (
>> } while (BufIdx < Op->LengthInBytes);
>> }
>>
>> - // Stop the transfer
>> + // Force bus state to idle, terminating any ongoing transfer
>> MmioWrite8 (I2c->MmioBase + F_I2C_REG_BCR, 0);
>>
>> if (!AtRuntime) {
>> --
>> 2.11.0
>>
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