[PATCH edk2-platforms 04/13] Silicon/NXP: Add i.MX6 Timer DXE driver

[Chris Co <Christopher.Co@microsoft.com>]

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      | 268 ++++++++++++++++++++
 Silicon/NXP/iMX6Pkg/Drivers/TimerDxe/TimerDxe.inf |  55 ++++
 2 files changed, 323 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..75c98dcff9ea
--- /dev/null
+++ b/Silicon/NXP/iMX6Pkg/Drivers/TimerDxe/Timer.c
@@ -0,0 +1,268 @@
+/** @file
+*
+*  Copyright (c) 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 <iMX6.h>
+#include <common_macros.h>
+#include <common_epit.h>
+
+#include <PiDxe.h>
+
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Library/BaseMemoryLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/UefiLib.h>
+#include <Library/PcdLib.h>
+#include <Library/IoLib.h>
+
+#include <Protocol/Timer.h>
+#include <Protocol/HardwareInterrupt.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"));
+  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
+  )
+{
+  EFI_STATUS  Status;
+  UINT32      TimerCount;
+  UINT16      epitPreScalar;
+
+  DEBUG ((DEBUG_VERBOSE, "++TimerDriverSetTimerPeriod(%d)\n", TimerPeriod));
+
+  PCSP_EPIT_REG g_pEPIT = (PCSP_EPIT_REG) CSP_BASE_REG_PA_EPIT1;
+
+  DEBUG ((DEBUG_VERBOSE, "TimerDriverSetTimerPeriod() disable timer. EPIT_REG adr=%p\n", g_pEPIT));
+
+  // First stop the timer.
+  INSREG32BF(&g_pEPIT->CR,EPIT_CR_EN,EPIT_CR_EN_DISABLE);
+
+  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 per
+  // i.MX 6Dual/6Quad Applications Processor Reference Manual, Rev. 3, 07/2015
+  // aim to have UEFI tick counting at 1 MHz clock or another frequency as set in pcd value
+  epitPreScalar = 68;
+  DEBUG((DEBUG_VERBOSE, "TimerDriverSetTimerPeriod() using corrected EPIT prescalar=%d\n", epitPreScalar));
+
+  OUTREG32(&g_pEPIT->CR,
+      CSP_BITFVAL(EPIT_CR_ENMOD, EPIT_CR_ENMOD_LOAD) |
+      CSP_BITFVAL(EPIT_CR_OCIEN, EPIT_CR_OCIEN_ENABLE) |
+      CSP_BITFVAL(EPIT_CR_RLD, EPIT_CR_RLD_RELOAD) |
+      CSP_BITFVAL(EPIT_CR_PRESCALAR, (epitPreScalar-1)) |  // bits 4-15, 000 to FFF.
+      CSP_BITFVAL(EPIT_CR_SWR, EPIT_CR_SWR_NORESET) |
+      CSP_BITFVAL(EPIT_CR_IOVW, EPIT_CR_IOVW_OVR) |
+      CSP_BITFVAL(EPIT_CR_DBGEN, EPIT_CR_DBGEN_ACTIVE) |
+      CSP_BITFVAL(EPIT_CR_WAITEN, EPIT_CR_WAITEN_ENABLE) |
+      CSP_BITFVAL(EPIT_CR_DOZEN, EPIT_CR_DOZEN_ENABLE) |
+      CSP_BITFVAL(EPIT_CR_STOPEN, EPIT_CR_STOPEN_ENABLE) |
+      CSP_BITFVAL(EPIT_CR_OM, EPIT_CR_OM_DICONNECT) |
+      CSP_BITFVAL(EPIT_CR_CLKSRC, EPIT_CR_CLKSRC_IPGCLK)); // source is crystal clock source (24 MHz)
+
+  // Clear timer compare interrupt flag (write-1-clear)
+  OUTREG32(&g_pEPIT->SR, CSP_BITFMASK(EPIT_SR_OCIF));
+    // Set the new compare value
+  TimerCount = (UINT32)(TimerPeriod / 10);
+
+  if((UINT64)TimerCount > (UINT64)0xffffffff)
+    TimerCount = 0xffffffff;
+
+  mCurrentTimerPeriod = TimerPeriod;
+
+  OUTREG32(&g_pEPIT->CMPR, TimerCount);
+  OUTREG32(&g_pEPIT->LR, TimerCount);
+  Status = gInterrupt->EnableInterruptSource(gInterrupt, mVector);
+  // turn the timer on
+  INSREG32BF(&g_pEPIT->CR,EPIT_CR_EN,EPIT_CR_EN_ENABLE);
+
+  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 g_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 (INREG32 (&g_pEPIT->SR) != 0) {
+    // Acknowledge the EPIT interrupt
+    OUTREG32 (&g_pEPIT->SR, 0x1);
+
+    // Signal end of interrupt early to help 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 = NULL;
+  EFI_STATUS  Status;
+  DEBUG ((DEBUG_VERBOSE, "++TimerInitialize()\n"));
+
+  mVector = IRQ_EPIT1;
+
+  // Find the interrupt controller protocol.  ASSERT if not found.
+  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 an 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..d574b99533ca
--- /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) 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                    = 0x00010005
+  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]
+  MdePkg/MdePkg.dec
+  EmbeddedPkg/EmbeddedPkg.dec
+  ArmPkg/ArmPkg.dec
+  Silicon/NXP/iMX6Pkg/iMX6Pkg.dec
+
+[LibraryClasses]
+  BaseLib
+  UefiRuntimeServicesTableLib
+  PerformanceLib
+  UefiLib
+  UefiBootServicesTableLib
+  BaseMemoryLib
+  DebugLib
+  UefiDriverEntryPoint
+  IoLib
+
+[Guids]
+
+[Protocols]
+  gEfiTimerArchProtocolGuid
+  gHardwareInterruptProtocolGuid
+
+[Pcd.common]
+  gEmbeddedTokenSpaceGuid.PcdTimerPeriod
+  gEmbeddedTokenSpaceGuid.PcdEmbeddedFdPerformanceCounterPeriodInNanoseconds
+
+[Depex]
+  gHardwareInterruptProtocolGuid
-- 
2.16.2.gvfs.1.33.gf5370f1