Re: [PATCH edk2-platforms 16/27] Silicon/NXP: Add i.MX6 Timer DXE driver

[Leif Lindholm <leif.lindholm@linaro.org>]

On Fri, Sep 21, 2018 at 08:26:08AM +0000, Chris Co wrote:
> This adds DXE support for EPIT timer on NXP i.MX6 SoCs.
> 
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Christopher Co <christopher.co@microsoft.com>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: Leif Lindholm <leif.lindholm@linaro.org>
> Cc: Michael D Kinney <michael.d.kinney@intel.com>
> ---
>  Silicon/NXP/iMX6Pkg/Drivers/TimerDxe/Timer.c      | 278 ++++++++++++++++++++
>  Silicon/NXP/iMX6Pkg/Drivers/TimerDxe/TimerDxe.inf |  55 ++++
>  2 files changed, 333 insertions(+)
> 
> diff --git a/Silicon/NXP/iMX6Pkg/Drivers/TimerDxe/Timer.c b/Silicon/NXP/iMX6Pkg/Drivers/TimerDxe/Timer.c
> new file mode 100644
> index 000000000000..6b4db6185b48
> --- /dev/null
> +++ b/Silicon/NXP/iMX6Pkg/Drivers/TimerDxe/Timer.c
> @@ -0,0 +1,278 @@
> +/** @file
> +*
> +*  Copyright (c) 2018 Microsoft Corporation. All rights reserved.
> +*
> +*  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
> +*  http://opensource.org/licenses/bsd-license.php
> +*
> +*  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
> +*  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
> +*
> +**/
> +
> +#include <PiDxe.h>
> +
> +#include <Library/BaseLib.h>
> +#include <Library/BaseMemoryLib.h>
> +#include <Library/DebugLib.h>
> +#include <Library/IoLib.h>
> +#include <Library/PcdLib.h>
> +#include <Library/UefiBootServicesTableLib.h>
> +#include <Library/UefiLib.h>
> +
> +#include <Protocol/HardwareInterrupt.h>
> +#include <Protocol/Timer.h>
> +
> +#include <common_epit.h>
> +#include <iMX6.h>
> +
> +// The notification function to call on every timer interrupt.
> +volatile EFI_TIMER_NOTIFY mTimerNotifyFunction = (EFI_TIMER_NOTIFY) NULL;
> +EFI_EVENT EfiExitBootServicesEvent = (EFI_EVENT) NULL;
> +
> +// Cached copy of the Hardware Interrupt protocol instance
> +EFI_HARDWARE_INTERRUPT_PROTOCOL *gInterrupt = NULL;
> +
> +// Cached interrupt vector
> +volatile UINTN  mVector;
> +UINT64 mCurrentTimerPeriod;
> +
> +EFI_STATUS
> +EFIAPI
> +TimerDriverRegisterHandler (
> +  IN EFI_TIMER_ARCH_PROTOCOL  *This,
> +  IN EFI_TIMER_NOTIFY         NotifyFunction
> +  )
> +{
> +  DEBUG ((DEBUG_VERBOSE, "++TimerDriverRegisterHandler()\n"));

Please use %a and __FUNCTION__ rather than manually typing the
function name. (Throughout the set.)

> +  if ((NotifyFunction == NULL) && (mTimerNotifyFunction == NULL)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if ((NotifyFunction != NULL) && (mTimerNotifyFunction != NULL)) {
> +    return EFI_ALREADY_STARTED;
> +  }
> +
> +  mTimerNotifyFunction = NotifyFunction;
> +  DEBUG ((DEBUG_VERBOSE, "--TimerDriverRegisterHandler()=ok\n"));
> +  return EFI_SUCCESS;
> +}
> +
> +EFI_STATUS
> +EFIAPI
> +TimerDriverSetTimerPeriod (
> +  IN EFI_TIMER_ARCH_PROTOCOL  *This,
> +  IN UINT64                   TimerPeriod
> +  )
> +{
> +  PCSP_EPIT_REG   pEpit;
> +  UINT16          EpitPreScalar;
> +  EFI_STATUS      Status;
> +  UINT32          TimerCount;
> +  UINT32          Value;
> +
> +  DEBUG ((DEBUG_VERBOSE, "++TimerDriverSetTimerPeriod(%d)\n", TimerPeriod));
> +
> +  pEpit = (PCSP_EPIT_REG) CSP_BASE_REG_PA_EPIT1;
> +  DEBUG ((DEBUG_VERBOSE,
> +          "TimerDriverSetTimerPeriod() disable timer. EPIT_REG adr=%p\n", pEpit));
> +
> +  // First stop the timer.
> +  Value = MmioRead32 ((UINTN)&pEpit->CR);
> +  Value &= ~(((1 << EPIT_CR_EN_WID) - 1) << EPIT_CR_EN_LSH);

Just to clarify comment from last email: I did mean global
search/replace on _LSH to _SHIFT for the entire set.

> +  Value |= (EPIT_CR_EN_DISABLE << EPIT_CR_EN_LSH);
> +  MmioWrite32 ((UINTN)&pEpit->CR, Value);
> +
> +  if (TimerPeriod == 0) {
> +    Status = gInterrupt->DisableInterruptSource (gInterrupt, mVector);
> +    mCurrentTimerPeriod = 0;
> +    DEBUG ((DEBUG_VERBOSE, "--TimerDriverSetTimerPeriod() Timer Disabled\n"));
> +    return Status;
> +  }
> +
> +  // Configure EPIT to be sourced from iMX6 24 MHz crystal oscialltor
> +  // Aim to have UEFI tick counting at 1 MHz clock or another frequency as set in pcd
> +  EpitPreScalar = 68;

That 68 needs a #define.

> +  DEBUG ((DEBUG_VERBOSE,
> +          "TimerDriverSetTimerPeriod() using corrected EPIT prescalar=%d\n",
> +          EpitPreScalar));
> +
> +  MmioWrite32 ((UINTN)&pEpit->CR,
> +            (EPIT_CR_ENMOD_LOAD << EPIT_CR_ENMOD_LSH) |
> +            (EPIT_CR_OCIEN_ENABLE << EPIT_CR_OCIEN_LSH) |
> +            (EPIT_CR_RLD_RELOAD << EPIT_CR_RLD_LSH) |
> +            ((EpitPreScalar - 1) << EPIT_CR_PRESCALAR_LSH) |
> +            (EPIT_CR_SWR_NORESET << EPIT_CR_SWR_LSH) |
> +            (EPIT_CR_IOVW_OVR << EPIT_CR_IOVW_LSH) |
> +            (EPIT_CR_DBGEN_ACTIVE << EPIT_CR_DBGEN_LSH) |
> +            (EPIT_CR_WAITEN_ENABLE << EPIT_CR_WAITEN_LSH) |
> +            (EPIT_CR_DOZEN_ENABLE << EPIT_CR_DOZEN_LSH) |
> +            (EPIT_CR_STOPEN_ENABLE << EPIT_CR_STOPEN_LSH) |
> +            (EPIT_CR_OM_DICONNECT << EPIT_CR_OM_LSH) |
> +            (EPIT_CR_CLKSRC_IPGCLK << EPIT_CR_CLKSRC_LSH));
> +
> +  // Clear timer compare interrupt flag (write-1-clear)
> +  MmioWrite32 ((UINTN)&pEpit->SR, ((1 << EPIT_SR_OCIF_WID) - 1) << EPIT_SR_OCIF_LSH);
> +  TimerCount = (UINT32) (TimerPeriod / 10);
> +  if ((UINT64)TimerCount > (UINT64)0xffffffff) {
> +    TimerCount = 0xffffffff;

MAX_UINT32?

/
    Leif

> +  }
> +
> +  mCurrentTimerPeriod = TimerPeriod;
> +  MmioWrite32 ((UINTN)&pEpit->CMPR, TimerCount);
> +  MmioWrite32 ((UINTN)&pEpit->LR, TimerCount);
> +  Status = gInterrupt->EnableInterruptSource (gInterrupt, mVector);
> +
> +  // Turn the timer on
> +  Value = MmioRead32 ((UINTN)&pEpit->CR);
> +  Value &= ~(((1 << EPIT_CR_EN_WID) - 1) << EPIT_CR_EN_LSH);
> +  Value |= EPIT_CR_EN_ENABLE << EPIT_CR_EN_LSH;
> +  MmioWrite32 ((UINTN)&pEpit->CR, Value);
> +
> +  DEBUG ((DEBUG_VERBOSE, "--TimerDriverSetTimerPeriod(%d)=%Xh\n", TimerPeriod,
> +          Status));
> +  return Status;
> +}
> +
> +EFI_STATUS
> +EFIAPI
> +TimerDriverGetTimerPeriod (
> +  IN EFI_TIMER_ARCH_PROTOCOL   *This,
> +  OUT UINT64                   *TimerPeriod
> +  )
> +{
> +  *TimerPeriod = mCurrentTimerPeriod;
> +  DEBUG ((DEBUG_VERBOSE, "+-TimerDriverGetTimerPeriod(%d)=ok\n",
> +          mCurrentTimerPeriod));
> +  return EFI_SUCCESS;
> +}
> +
> +VOID
> +EFIAPI
> +TimerInterruptHandler (
> +  IN  HARDWARE_INTERRUPT_SOURCE   Source,
> +  IN  EFI_SYSTEM_CONTEXT          SystemContext
> +  )
> +{
> +  EFI_TPL OriginalTPL;
> +  PCSP_EPIT_REG pEpit;
> +
> +  pEpit = (PCSP_EPIT_REG) CSP_BASE_REG_PA_EPIT1;
> +
> +  // DXE core uses this callback for the EFI timer tick. The DXE core uses locks
> +  // that raise to TPL_HIGH and then restore back to current level. Thus we need
> +  // to make sure TPL level is set to TPL_HIGH while we are handling the timer tick.
> +  OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);
> +
> +  // Check if the timer interrupt is active
> +  if (MmioRead32 ((UINTN)&pEpit->SR) != 0) {
> +    // Acknowledge the EPIT interrupt
> +    MmioWrite32 ((UINTN)&pEpit->SR, 0x1);
> +
> +    // Signal EOI to avoid losing subsequent ticks from long duration handlers
> +    gInterrupt->EndOfInterrupt (gInterrupt, Source);
> +
> +    if (mTimerNotifyFunction) {
> +      mTimerNotifyFunction (mCurrentTimerPeriod);
> +    }
> +  }
> +
> +  gBS->RestoreTPL (OriginalTPL);
> +}
> +
> +EFI_STATUS
> +EFIAPI
> +TimerDriverGenerateSoftInterrupt (
> +  IN EFI_TIMER_ARCH_PROTOCOL  *This
> +  )
> +{
> +  return EFI_UNSUPPORTED;
> +}
> +
> +EFI_TIMER_ARCH_PROTOCOL gTimer = {
> +  TimerDriverRegisterHandler,
> +  TimerDriverSetTimerPeriod,
> +  TimerDriverGetTimerPeriod,
> +  TimerDriverGenerateSoftInterrupt
> +};
> +
> +VOID
> +EFIAPI
> +ExitBootServicesEvent (
> +  IN EFI_EVENT  Event,
> +  IN VOID       *Context
> +  )
> +{
> +  EFI_STATUS  Status;
> +
> +  DEBUG ((DEBUG_INFO, "Disabling EPIT timer on ExitBootServicesEvent"));
> +
> +  // Disable the timer
> +  Status = TimerDriverSetTimerPeriod (&gTimer, 0);
> +  ASSERT_EFI_ERROR (Status);
> +}
> +
> +EFI_STATUS
> +EFIAPI
> +TimerInitialize (
> +  IN EFI_HANDLE         ImageHandle,
> +  IN EFI_SYSTEM_TABLE   *SystemTable
> +)
> +{
> +  EFI_HANDLE  Handle;
> +  EFI_STATUS  Status;
> +  DEBUG ((DEBUG_VERBOSE, "++TimerInitialize()\n"));
> +
> +  Handle = NULL;
> +  mVector = IRQ_EPIT1;
> +
> +  // Find the interrupt controller protocol.
> +  Status = gBS->LocateProtocol (
> +             &gHardwareInterruptProtocolGuid,
> +             NULL,
> +             (VOID **) &gInterrupt);
> +  ASSERT_EFI_ERROR (Status);
> +
> +  // Disable the timer
> +  Status = TimerDriverSetTimerPeriod (&gTimer, 0);
> +  ASSERT_EFI_ERROR (Status);
> +
> +  // Install interrupt handler
> +  Status = gInterrupt->RegisterInterruptSource (gInterrupt, mVector,
> +           TimerInterruptHandler);
> +  ASSERT_EFI_ERROR (Status);
> +
> +  // Set up default timer
> +  Status = TimerDriverSetTimerPeriod (&gTimer, FixedPcdGet32 (PcdTimerPeriod));
> +  ASSERT_EFI_ERROR (Status);
> +
> +  DEBUG ((
> +           DEBUG_VERBOSE,
> +           "EPIT Timer initialized to default period %d x 100ns ~ %dms\n",
> +           FixedPcdGet32 (PcdTimerPeriod),
> +           FixedPcdGet32 (PcdTimerPeriod) / 10000));
> +
> +  // Install the Timer Architectural Protocol onto a new handle
> +  Status = gBS->InstallMultipleProtocolInterfaces (
> +             &Handle,
> +             &gEfiTimerArchProtocolGuid,
> +             &gTimer,
> +             NULL);
> +
> +  ASSERT_EFI_ERROR (Status);
> +
> +  // Register for ExitBootServicesEvent
> +  Status = gBS->CreateEvent (
> +             EVT_SIGNAL_EXIT_BOOT_SERVICES,
> +             TPL_NOTIFY,
> +             ExitBootServicesEvent,
> +             NULL,
> +             &EfiExitBootServicesEvent);
> +
> +  ASSERT_EFI_ERROR (Status);
> +
> +  DEBUG ((DEBUG_VERBOSE, "--TimerInitialize()\n"));
> +  return Status;
> +}
> diff --git a/Silicon/NXP/iMX6Pkg/Drivers/TimerDxe/TimerDxe.inf b/Silicon/NXP/iMX6Pkg/Drivers/TimerDxe/TimerDxe.inf
> new file mode 100644
> index 000000000000..adcc158e29ab
> --- /dev/null
> +++ b/Silicon/NXP/iMX6Pkg/Drivers/TimerDxe/TimerDxe.inf
> @@ -0,0 +1,55 @@
> +#/** @file
> +#
> +#  Copyright (c) 2009, Apple Inc. All rights reserved.<BR>
> +#  Copyright (c) 2018 Microsoft Corporation. All rights reserved.
> +#
> +#  All rights reserved. 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
> +#  http://opensource.org/licenses/bsd-license.php
> +#
> +#  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
> +#  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
> +#
> +#**/
> +
> +[Defines]
> +  INF_VERSION                    = 0x0001001A
> +  BASE_NAME                      = iMX6TimerDxe
> +  FILE_GUID                      = 7CAF576F-F1D9-4104-A922-CB64537FD7AE
> +  MODULE_TYPE                    = DXE_DRIVER
> +  VERSION_STRING                 = 1.0
> +  ENTRY_POINT                    = TimerInitialize
> +
> +[Sources.common]
> +  Timer.c
> +
> +[Packages]
> +  ArmPkg/ArmPkg.dec
> +  EmbeddedPkg/EmbeddedPkg.dec
> +  MdePkg/MdePkg.dec
> +  Silicon/NXP/iMX6Pkg/iMX6Pkg.dec
> +
> +[LibraryClasses]
> +  BaseLib
> +  BaseMemoryLib
> +  DebugLib
> +  IoLib
> +  PerformanceLib
> +  UefiBootServicesTableLib
> +  UefiDriverEntryPoint
> +  UefiLib
> +  UefiRuntimeServicesTableLib
> +
> +[Guids]
> +
> +[Protocols]
> +  gEfiTimerArchProtocolGuid
> +  gHardwareInterruptProtocolGuid
> +
> +[Pcd.common]
> +  gEmbeddedTokenSpaceGuid.PcdEmbeddedFdPerformanceCounterPeriodInNanoseconds
> +  gEmbeddedTokenSpaceGuid.PcdTimerPeriod
> +
> +[Depex]
> +  gHardwareInterruptProtocolGuid
> -- 
> 2.16.2.gvfs.1.33.gf5370f1
>