From: "Laszlo Ersek" <lersek@redhat.com>
To: devel@edk2.groups.io, ardb@kernel.org
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>,
Leif Lindholm <quic_llindhol@quicinc.com>
Subject: Re: [edk2-devel] [PATCH] ArmPlatformPkg/PL031RealTimeClockLib: remove superfluous instance init steps
Date: Tue, 24 Oct 2023 18:50:58 +0200 [thread overview]
Message-ID: <2b57b0c9-7717-56f5-ab0e-062e0fd0c8b8@redhat.com> (raw)
In-Reply-To: <CAMj1kXE-2aJ2RBnOa_qvvuUY_Xab1+QRBoAxK8wBxiUCajjiZQ@mail.gmail.com>
On 10/20/23 14:27, Ard Biesheuvel wrote:
> On Fri, 20 Oct 2023 at 14:17, Laszlo Ersek <lersek@redhat.com> wrote:
>>
>> RealTimeClockLib instances are consumed by edk2's
>> EmbeddedPkg/RealTimeClockRuntimeDxe driver. In its entry point function
>> InitializeRealTimeClock(), the driver:
>>
>> (1) calls LibRtcInitialize(),
>>
>> (2) sets the GetTime(), SetTime(), GetWakeupTime() and SetWakeupTime()
>> runtime services to its own similarly-named functions -- where those
>> functions wrap the corresponding RealTimeClockLib APIs,
>>
>> (3) installs EFI_REAL_TIME_CLOCK_ARCH_PROTOCOL with a NULL protocol
>> interface.
>>
>> Steps (2) and (3) conform to PI v1.8 sections II-9.7.2.4 through
>> II-9.7.2.7.
>>
>> However, this means that LibRtcInitialize() (of any RealTimeClockLib
>> instance) should not itself (a) set the GetTime(), SetTime(),
>> GetWakeupTime() and SetWakeupTime() runtime services, nor (b) install
>> EFI_REAL_TIME_CLOCK_ARCH_PROTOCOL. The runtime service pointers will be
>> overwritten in step (2) anyway, and step (3) will uselessly install a
>> second (NULL-interface) EFI_REAL_TIME_CLOCK_ARCH_PROTOCOL instance in the
>> protocol database. (The protocol only serves to notify the DXE Foundation
>> about said runtime services being available.)
>>
>> Clean up ArmPlatformPkg/PL031RealTimeClockLib accordingly (it only has
>> code that's redundant for step (3); it does not try to set "gRT" fields).
>>
>> (Note that the lib instance INF file already does not list
>> gEfiRealTimeClockArchProtocolGuid.)
>>
>> Tested with ArmVirtQemu.
>>
>> Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
>> Cc: Leif Lindholm <quic_llindhol@quicinc.com>
>> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=4565
>> Signed-off-by: Laszlo Ersek <lersek@redhat.com>
>> ---
>>
>> Notes:
>> context:-W
>>
>> ArmPlatformPkg/Library/PL031RealTimeClockLib/PL031RealTimeClockLib.c | 13 -------------
>> 1 file changed, 13 deletions(-)
>>
>
> Acked-by: Ard Biesheuvel <ardb@kernel.org>
>
> Thanks a lot for cleaning up this mess.
Merged via <https://github.com/tianocore/edk2/pull/4950> as commit
d85bf54b7f46.
Thanks!
Laszlo
>
>
>> diff --git a/ArmPlatformPkg/Library/PL031RealTimeClockLib/PL031RealTimeClockLib.c b/ArmPlatformPkg/Library/PL031RealTimeClockLib/PL031RealTimeClockLib.c
>> index 9e852696d2fd..1896f9d16d3b 100644
>> --- a/ArmPlatformPkg/Library/PL031RealTimeClockLib/PL031RealTimeClockLib.c
>> +++ b/ArmPlatformPkg/Library/PL031RealTimeClockLib/PL031RealTimeClockLib.c
>> @@ -1,34 +1,32 @@
>> /** @file
>> Implement EFI RealTimeClock runtime services via RTC Lib.
>>
>> Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>
>> Copyright (c) 2011 - 2020, Arm Limited. All rights reserved.<BR>
>> Copyright (c) 2019, Linaro Ltd. All rights reserved.<BR>
>>
>> SPDX-License-Identifier: BSD-2-Clause-Patent
>>
>> **/
>>
>> #include <PiDxe.h>
>>
>> #include <Guid/EventGroup.h>
>> #include <Guid/GlobalVariable.h>
>>
>> #include <Library/BaseLib.h>
>> #include <Library/DebugLib.h>
>> #include <Library/DxeServicesTableLib.h>
>> #include <Library/IoLib.h>
>> #include <Library/MemoryAllocationLib.h>
>> #include <Library/PcdLib.h>
>> #include <Library/RealTimeClockLib.h>
>> #include <Library/TimeBaseLib.h>
>> #include <Library/UefiBootServicesTableLib.h>
>> #include <Library/UefiLib.h>
>> #include <Library/UefiRuntimeServicesTableLib.h>
>> #include <Library/UefiRuntimeLib.h>
>>
>> -#include <Protocol/RealTimeClock.h>
>> -
>> #include "PL031RealTimeClock.h"
>>
>> STATIC BOOLEAN mPL031Initialized = FALSE;
>> @@ -307,52 +305,41 @@ EFIAPI
>> LibRtcInitialize (
>> IN EFI_HANDLE ImageHandle,
>> IN EFI_SYSTEM_TABLE *SystemTable
>> )
>> {
>> EFI_STATUS Status;
>> - EFI_HANDLE Handle;
>>
>> // Initialize RTC Base Address
>> mPL031RtcBase = PcdGet32 (PcdPL031RtcBase);
>>
>> // Declare the controller as EFI_MEMORY_RUNTIME
>> Status = gDS->AddMemorySpace (
>> EfiGcdMemoryTypeMemoryMappedIo,
>> mPL031RtcBase,
>> SIZE_4KB,
>> EFI_MEMORY_UC | EFI_MEMORY_RUNTIME
>> );
>> if (EFI_ERROR (Status)) {
>> return Status;
>> }
>>
>> Status = gDS->SetMemorySpaceAttributes (mPL031RtcBase, SIZE_4KB, EFI_MEMORY_UC | EFI_MEMORY_RUNTIME);
>> if (EFI_ERROR (Status)) {
>> return Status;
>> }
>>
>> - // Install the protocol
>> - Handle = NULL;
>> - Status = gBS->InstallMultipleProtocolInterfaces (
>> - &Handle,
>> - &gEfiRealTimeClockArchProtocolGuid,
>> - NULL,
>> - NULL
>> - );
>> - ASSERT_EFI_ERROR (Status);
>> -
>> //
>> // Register for the virtual address change event
>> //
>> Status = gBS->CreateEventEx (
>> EVT_NOTIFY_SIGNAL,
>> TPL_NOTIFY,
>> VirtualNotifyEvent,
>> NULL,
>> &gEfiEventVirtualAddressChangeGuid,
>> &mRtcVirtualAddrChangeEvent
>> );
>> ASSERT_EFI_ERROR (Status);
>>
>> return Status;
>> }
>
>
>
>
>
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prev parent reply other threads:[~2023-10-24 16:51 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-20 12:17 [edk2-devel] [PATCH] ArmPlatformPkg/PL031RealTimeClockLib: remove superfluous instance init steps Laszlo Ersek
2023-10-20 12:27 ` Ard Biesheuvel
2023-10-24 16:50 ` Laszlo Ersek [this message]
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