[PATCH edk2-platforms 05/13] Silicon/NXP: Add i.MX6 GPT Timer library

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

This adds support for GPT 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/Library/TimerLib/TimerLib.c   | 257 ++++++++++++++++++++
 Silicon/NXP/iMX6Pkg/Library/TimerLib/TimerLib.inf |  37 +++
 2 files changed, 294 insertions(+)

diff --git a/Silicon/NXP/iMX6Pkg/Library/TimerLib/TimerLib.c b/Silicon/NXP/iMX6Pkg/Library/TimerLib/TimerLib.c
new file mode 100644
index 000000000000..54dd3b5f7004
--- /dev/null
+++ b/Silicon/NXP/iMX6Pkg/Library/TimerLib/TimerLib.c
@@ -0,0 +1,257 @@
+/** @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 <Uefi.h>
+#include <Base.h>
+
+#include <common_macros.h>
+#include <iMX6.h>
+#include <common_gpt.h>
+
+#include <Library/PcdLib.h>
+#include <Library/IoLib.h>
+#include <Library/TimerLib.h>
+#include <Library/DebugLib.h>
+#include <Library/BaseLib.h>
+#include <Library/ArmLib.h>
+
+// Select appropriate multiply function for platform architecture.
+#ifdef MDE_CPU_ARM
+#define MultU64xN MultU64x32
+#else
+#define MultU64xN MultU64x64
+#endif
+
+RETURN_STATUS
+EFIAPI
+TimerConstructor (
+  VOID
+  )
+{
+  PCSP_GPT_REGS pGPT;
+  UINT32 FreqPreScale;
+
+  pGPT = (PCSP_GPT_REGS)CSP_BASE_REG_PA_GPT;
+
+  ASSERT(SOC_OSC_FREQUENCY_REF_HZ >= PcdGet32 (PcdArmArchTimerFreqInHz));
+
+  // Calculate the scale factor since we are using the 24Mhz oscillator
+  // as reference.
+  FreqPreScale = SOC_OSC_FREQUENCY_REF_HZ / PcdGet32 (PcdArmArchTimerFreqInHz);
+  ASSERT(FreqPreScale <= (1<<GPT_PR_PRESCALER_WID));
+
+  // Set the frequency scale
+  OUTREG32(&pGPT->PR,FreqPreScale - 1);
+
+#if defined(CPU_IMX6DQ)
+  // Set GPT configuration:
+  // - GPT Enabled
+  // - Use the 24Mhz oscillator source
+  OUTREG32(&pGPT->CR,
+    CSP_BITFVAL(GPT_CR_EN, GPT_CR_EN_ENABLE) |
+    CSP_BITFVAL(GPT_CR_CLKSRC, GPT_CR_CLKSRC_CLK24M));
+#elif defined(CPU_IMX6SDL) || defined(CPU_IMX6SX)
+  // Set GPT configuration:
+  // - GPT Enabled
+  // - Enable 24 Mhz Oscillator
+  // - Use the 24Mhz oscillator source
+  OUTREG32(&pGPT->CR,
+    CSP_BITFVAL(GPT_CR_EN, GPT_CR_EN_ENABLE) |
+    CSP_BITFVAL(GPT_CR_EN_24M, GPT_CR_EN_24M_ENABLE) |
+    CSP_BITFVAL(GPT_CR_CLKSRC, GPT_CR_CLKSRC_CLK24M));
+#else
+#error CPU Preprocessor Flag Not Defined
+#endif
+
+  return EFI_SUCCESS;
+}
+
+/**
+  Stalls the CPU for at least the given number of microseconds.
+
+  Stalls the CPU for the number of microseconds specified by MicroSeconds.
+
+  @param  MicroSeconds  The minimum number of microseconds to delay.
+
+  @return The value of MicroSeconds inputted.
+
+**/
+UINTN
+EFIAPI
+MicroSecondDelay (
+  IN      UINTN                     MicroSeconds
+  )
+{
+  UINT64 TimerTicks64;
+  UINT32 CurCounterRead;
+  UINT32 PrevCounterRead;
+  UINT64 CountOffset;
+
+  // Convert uSec delay to counter ticks:
+  TimerTicks64      = ((UINT64)MicroSeconds * PcdGet32 (PcdArmArchTimerFreqInHz)) / 1000000U;
+  CurCounterRead    = (UINT32)GetPerformanceCounter();
+  PrevCounterRead   = CurCounterRead;
+  TimerTicks64      += (UINT64)CurCounterRead;
+  CountOffset       = 0;
+
+  // GPT is a 32bit counter, thus we need to handle rollover cases.
+  while(((UINT64)CurCounterRead + CountOffset) < TimerTicks64) {
+
+    CurCounterRead = (UINT32)GetPerformanceCounter();
+    if (CurCounterRead < PrevCounterRead) {
+        CountOffset += 0x100000000;
+    }
+
+    PrevCounterRead = CurCounterRead;
+  }
+
+  return MicroSeconds;
+}
+
+/**
+  Stalls the CPU for at least the given number of nanoseconds.
+
+  Stalls the CPU for the number of nanoseconds specified by NanoSeconds.
+
+  @param  NanoSeconds The minimum number of nanoseconds to delay.
+
+  @return The value of NanoSeconds inputted.
+
+**/
+UINTN
+EFIAPI
+NanoSecondDelay (
+  IN      UINTN                     NanoSeconds
+  )
+{
+  if (NanoSeconds < (0xffffffff - 999)) {
+    NanoSeconds += 999;
+  }
+  MicroSecondDelay(NanoSeconds / 1000);
+
+  return 0;
+}
+
+/**
+  Retrieves the current value of a 64-bit free running performance counter.
+
+  The counter can either count up by 1 or count down by 1. If the physical
+  performance counter counts by a larger increment, then the counter values
+  must be translated. The properties of the counter can be retrieved from
+  GetPerformanceCounterProperties().
+
+  @return The current value of the free running performance counter.
+
+**/
+UINT64
+EFIAPI
+GetPerformanceCounter (
+  VOID
+  )
+{
+  PCSP_GPT_REGS pGPT = (PCSP_GPT_REGS)CSP_BASE_REG_PA_GPT;
+
+  return INREG32 (&pGPT->CNT);
+}
+
+/**
+  Retrieves the 64-bit frequency in Hz and the range of performance counter
+  values.
+
+  If StartValue is not NULL, then the value that the performance counter starts
+  with immediately after is it rolls over is returned in StartValue. If
+  EndValue is not NULL, then the value that the performance counter end with
+  immediately before it rolls over is returned in EndValue. The 64-bit
+  frequency of the performance counter in Hz is always returned. If StartValue
+  is less than EndValue, then the performance counter counts up. If StartValue
+  is greater than EndValue, then the performance counter counts down. For
+  example, a 64-bit free running counter that counts up would have a StartValue
+  of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter
+  that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.
+
+  @param  StartValue  The value the performance counter starts with when it
+                      rolls over.
+  @param  EndValue    The value that the performance counter ends with before
+                      it rolls over.
+
+  @return The frequency in Hz.
+
+**/
+UINT64
+EFIAPI
+GetPerformanceCounterProperties (
+  OUT      UINT64                    *StartValue,  OPTIONAL
+  OUT      UINT64                    *EndValue     OPTIONAL
+  )
+{
+  if (StartValue != NULL) {
+    *StartValue = 0x0;
+  }
+
+  if (EndValue != NULL) {
+    *EndValue = 0xFFFFFFFF;
+  }
+
+  return PcdGet32 (PcdArmArchTimerFreqInHz);
+}
+
+/**
+  Converts elapsed ticks of performance counter to time in nanoseconds.
+
+  This function converts the elapsed ticks of running performance counter to
+  time value in unit of nanoseconds.
+
+  @param  Ticks     The number of elapsed ticks of running performance counter.
+
+  @return The elapsed time in nanoseconds.
+
+**/
+UINT64
+EFIAPI
+GetTimeInNanoSecond (
+  IN      UINT64                     Ticks
+  )
+{
+  UINT64  NanoSeconds;
+  UINT32  Remainder;
+  UINT32  TimerFreq;
+
+  TimerFreq = PcdGet32 (PcdArmArchTimerFreqInHz);
+
+  //
+  //          Ticks
+  // Time = --------- x 1,000,000,000
+  //        Frequency
+  //
+  NanoSeconds = MultU64xN (
+                  DivU64x32Remainder (
+                    Ticks,
+                    TimerFreq,
+                    &Remainder),
+                  1000000000U
+                  );
+
+  //
+  // Frequency < 0x100000000, so Remainder < 0x100000000, then (Remainder * 1,000,000,000)
+  // will not overflow 64-bit.
+  //
+  NanoSeconds += DivU64x32 (
+                   MultU64xN (
+                     (UINT64) Remainder,
+                     1000000000U),
+                   TimerFreq
+                   );
+
+  return NanoSeconds;
+}
diff --git a/Silicon/NXP/iMX6Pkg/Library/TimerLib/TimerLib.inf b/Silicon/NXP/iMX6Pkg/Library/TimerLib/TimerLib.inf
new file mode 100644
index 000000000000..4715b90db153
--- /dev/null
+++ b/Silicon/NXP/iMX6Pkg/Library/TimerLib/TimerLib.inf
@@ -0,0 +1,37 @@
+## @file
+#
+#  Copyright (c) Microsoft Corporation. All rights reserved.
+#  Copyright (c) 2007 - 2008, Intel Corporation.
+#
+#  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                      = iMX6TimerLib
+  FILE_GUID                      = 2956C1A6-6FF8-4763-9FD8-D45892E025E3
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = TimerLib
+
+[Sources.common]
+  TimerLib.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  ArmPkg/ArmPkg.dec
+  Silicon/NXP/iMX6Pkg/iMX6Pkg.dec
+
+[LibraryClasses]
+  DebugLib
+  IoLib
+
+[Pcd]
+  gArmTokenSpaceGuid.PcdArmArchTimerFreqInHz
-- 
2.16.2.gvfs.1.33.gf5370f1