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]> > --- > 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 > _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
