Mike, Just get your point, that means the [31:24] will be always ignored regardless of the ACPI timer is 24Bits or 32Bits.
How about updating the comments like below? "Note: The implementation only uses the lower 24-bits of the ACPI timer and can be compatible with both 24-bits and 32-bits ACPI timers." Thanks, Star -----Original Message----- From: Kinney, Michael D Sent: Wednesday, September 28, 2016 10:58 PM To: Zeng, Star <star.z...@intel.com>; edk2-devel@lists.01.org; Kinney, Michael D <michael.d.kin...@intel.com> Cc: Laszlo Ersek <ler...@redhat.com>; Yao, Jiewen <jiewen....@intel.com>; Gao, Liming <liming....@intel.com>; Zeng, Star <star.z...@intel.com> Subject: RE: [edk2] [PATCH V2] PcAtChipsetPkg AcpiTimerLib: Clear bits [31:24] after reading by IoRead32() Star, I think the comment should be updated. This updated algorithm only uses the lower 24-bits of the ACPI timer. It is compatible with both 24-bit and 32-bit ACPI timers. Mike > -----Original Message----- > From: edk2-devel [mailto:edk2-devel-boun...@lists.01.org] On Behalf Of > Star Zeng > Sent: Wednesday, September 28, 2016 5:49 AM > To: edk2-devel@lists.01.org > Cc: Laszlo Ersek <ler...@redhat.com>; Yao, Jiewen > <jiewen....@intel.com>; Gao, Liming <liming....@intel.com>; Zeng, Star > <star.z...@intel.com> > Subject: [edk2] [PATCH V2] PcAtChipsetPkg AcpiTimerLib: Clear bits > [31:24] after reading by IoRead32() > > From: "Zeng, Star" <star.z...@intel.com> > > Clear bits [31:24] when reading ACPI timer count by IoRead32(), also > add comments "Note: The library only supports 24Bits ACPI timer" in INF. > > Cc: Jiewen Yao <jiewen....@intel.com> > Cc: Liming Gao <liming....@intel.com> > Cc: Laszlo Ersek <ler...@redhat.com> > Contributed-under: TianoCore Contribution Agreement 1.0 > Signed-off-by: Star Zeng <star.z...@intel.com> > --- > PcAtChipsetPkg/Library/AcpiTimerLib/AcpiTimerLib.c | 8 ++++---- > PcAtChipsetPkg/Library/AcpiTimerLib/BaseAcpiTimerLib.inf | 6 ++++-- > PcAtChipsetPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.inf | 8 +++++--- > 3 files changed, 13 insertions(+), 9 deletions(-) > > diff --git a/PcAtChipsetPkg/Library/AcpiTimerLib/AcpiTimerLib.c > b/PcAtChipsetPkg/Library/AcpiTimerLib/AcpiTimerLib.c > index 020031e3f4a5..792781a33f3f 100644 > --- a/PcAtChipsetPkg/Library/AcpiTimerLib/AcpiTimerLib.c > +++ b/PcAtChipsetPkg/Library/AcpiTimerLib/AcpiTimerLib.c > @@ -162,14 +162,14 @@ InternalAcpiDelay ( > // > // The target timer count is calculated here > // > - Ticks = IoRead32 (Port) + Delay; > + Ticks = IoBitFieldRead32 (Port, 0, 23) + Delay; > Delay = BIT22; > // > // Wait until time out > // Delay >= 2^23 could not be handled by this function > // Timer wrap-arounds are handled correctly by this function > // > - while (((Ticks - IoRead32 (Port)) & BIT23) == 0) { > + while (((Ticks - IoBitFieldRead32 (Port, 0, 23)) & BIT23) == 0) { > CpuPause (); > } > } while (Times-- > 0); > @@ -371,7 +371,7 @@ InternalCalculateTscFrequency ( > // Use 363 * 9861 = 3579543 Hz which is within 2 Hz of > ACPI_TIMER_FREQUENCY. > // 363 counts is a calibration time of 101.4 uS. > // > - Ticks = IoRead32 (TimerAddr) + 363; > + Ticks = IoBitFieldRead32 (TimerAddr, 0, 23) + 363; > > StartTSC = AsmReadTsc (); // Get > base value > for the TSC > // > @@ -380,7 +380,7 @@ InternalCalculateTscFrequency ( > // When the current ACPI timer value is greater than 'Ticks', > // the while loop will exit. > // > - while (((Ticks - IoRead32 (TimerAddr)) & BIT23) == 0) { > + while (((Ticks - IoBitFieldRead32 (TimerAddr, 0, 23)) & BIT23) == > + 0) { > CpuPause(); > } > EndTSC = AsmReadTsc (); // TSC > value 101.4 > us later > diff --git a/PcAtChipsetPkg/Library/AcpiTimerLib/BaseAcpiTimerLib.inf > b/PcAtChipsetPkg/Library/AcpiTimerLib/BaseAcpiTimerLib.inf > index 48caebff1354..913fbfe7d30e 100644 > --- a/PcAtChipsetPkg/Library/AcpiTimerLib/BaseAcpiTimerLib.inf > +++ b/PcAtChipsetPkg/Library/AcpiTimerLib/BaseAcpiTimerLib.inf > @@ -2,9 +2,11 @@ > # Base ACPI Timer Library > # > # Provides basic timer support using the ACPI timer hardware. The > performance -# counter features are provided by the processors time stamp > counter. > +# counter features are provided by the processors time stamp counter. > # > -# Copyright (c) 2013 - 2015, Intel Corporation. All rights > reserved.<BR> > +# Note: The library only supports 24Bits ACPI timer. > +# > +# Copyright (c) 2013 - 2016, Intel Corporation. All rights > +reserved.<BR> > # This program and the accompanying materials # are licensed and > made available under the terms and conditions of the BSD License # > which accompanies this distribution. The full text of the license may > be found at diff --git > a/PcAtChipsetPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.inf > b/PcAtChipsetPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.inf > index 3446c03eda21..33d4970afc57 100644 > --- a/PcAtChipsetPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.inf > +++ b/PcAtChipsetPkg/Library/AcpiTimerLib/DxeAcpiTimerLib.inf > @@ -2,9 +2,11 @@ > # DXE ACPI Timer Library > # > # Provides basic timer support using the ACPI timer hardware. The > performance -# counter features are provided by the processors time stamp > counter. > +# counter features are provided by the processors time stamp counter. > # > -# Copyright (c) 2013 - 2015, Intel Corporation. All rights > reserved.<BR> > +# Note: The library only supports 24Bits ACPI timer. > +# > +# Copyright (c) 2013 - 2016, Intel Corporation. All rights > +reserved.<BR> > # This program and the accompanying materials # are licensed and > made available under the terms and conditions of the BSD License # > which accompanies this distribution. The full text of the license may > be found at @@ -49,4 +51,4 @@ [Pcd] > gPcAtChipsetPkgTokenSpaceGuid.PcdAcpiIoPciBarRegisterOffset ## CONSUMES > gPcAtChipsetPkgTokenSpaceGuid.PcdAcpiIoPortBaseAddress ## CONSUMES > gPcAtChipsetPkgTokenSpaceGuid.PcdAcpiPm1TmrOffset ## CONSUMES > - gPcAtChipsetPkgTokenSpaceGuid.PcdAcpiIoPortBaseAddressMask ## CONSUMES > \ No newline at end of file > + gPcAtChipsetPkgTokenSpaceGuid.PcdAcpiIoPortBaseAddressMask ## CONSUMES > -- > 2.8.1.windows.1 > > _______________________________________________ > edk2-devel mailing list > edk2-devel@lists.01.org > https://lists.01.org/mailman/listinfo/edk2-devel _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
