| Message ID | 20180221110421.18435-1-ard.biesheuvel@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | [edk2,edk2-platforms,v2] Silicon/Socionext/SynQuacerI2cDxe: fix TPL handling bug | expand |
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 <ard.biesheuvel@linaro.org> Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org> > --- > 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 edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
On 21 February 2018 at 11:11, Leif Lindholm <leif.lindholm@linaro.org> 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 <ard.biesheuvel@linaro.org> > > Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org> > 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 >> _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
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) {
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 <ard.biesheuvel@linaro.org> --- 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(-) -- 2.11.0 _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel