[edk2-devel] [PATCH v5 25/36] OvmfPkg/LoongArchVirt: Add stable timer driver

["Chao Li" <lichao@loongson.cn>]

Add a CPU timer driver named StableTimerDxe, which proviedes
EFI_TIMER_ARCH_PROTOCOL for LoongArch.

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4584

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Chao Li <lichao@loongson.cn>
Co-authored-by: Baoqi Zhang <zhangbaoqi@loongson.cn>
---
 .../Drivers/StableTimerDxe/Timer.c            | 381 ++++++++++++++++++
 .../Drivers/StableTimerDxe/Timer.h            | 127 ++++++
 .../Drivers/StableTimerDxe/TimerDxe.inf       |  41 ++
 3 files changed, 549 insertions(+)
 create mode 100644 OvmfPkg/LoongArchVirt/Drivers/StableTimerDxe/Timer.c
 create mode 100644 OvmfPkg/LoongArchVirt/Drivers/StableTimerDxe/Timer.h
 create mode 100644 OvmfPkg/LoongArchVirt/Drivers/StableTimerDxe/TimerDxe.inf

diff --git a/OvmfPkg/LoongArchVirt/Drivers/StableTimerDxe/Timer.c b/OvmfPkg/LoongArchVirt/Drivers/StableTimerDxe/Timer.c
new file mode 100644
index 0000000000..0e0f10970a
--- /dev/null
+++ b/OvmfPkg/LoongArchVirt/Drivers/StableTimerDxe/Timer.c
@@ -0,0 +1,381 @@
+/** @file
+  Timer Architectural Protocol as defined in the DXE CIS
+
+  Copyright (c) 2024 Loongson Technology Corporation Limited. All rights reserved.<BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Protocol/Cpu.h>
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Library/TimerLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+#include <Register/LoongArch64/Csr.h>
+#include "Timer.h"
+
+//
+// The handle onto which the Timer Architectural Protocol will be installed
+//
+EFI_HANDLE  mTimerHandle             = NULL;
+EFI_EVENT   EfiExitBootServicesEvent = (EFI_EVENT)NULL;
+
+//
+// The Timer Architectural Protocol that this driver produces
+//
+EFI_TIMER_ARCH_PROTOCOL  mTimer = {
+  TimerDriverRegisterHandler,
+  TimerDriverSetTimerPeriod,
+  TimerDriverGetTimerPeriod,
+  TimerDriverGenerateSoftInterrupt
+};
+
+//
+// Pointer to the CPU Architectural Protocol instance
+//
+EFI_CPU_ARCH_PROTOCOL  *mCpu;
+
+//
+// The notification function to call on every timer interrupt.
+// A bug in the compiler prevents us from initializing this here.
+//
+EFI_TIMER_NOTIFY  mTimerNotifyFunction;
+
+/**
+  Sets the counter value for timer.
+
+  @param Count    The 16-bit counter value to program into stable timer.
+
+  @retval VOID
+**/
+VOID
+SetPitCount (
+  IN UINT64  Count
+  )
+{
+  if (Count <= 4) {
+    return;
+  }
+
+  Count &= LOONGARCH_CSR_TMCFG_TIMEVAL;
+  Count |= LOONGARCH_CSR_TMCFG_EN | LOONGARCH_CSR_TMCFG_PERIOD;
+  CsrWrite (LOONGARCH_CSR_TMCFG, Count);
+}
+
+/**
+  Timer Interrupt Handler.
+
+  @param InterruptType    The type of interrupt that occurred
+  @param SystemContext    A pointer to the system context when the interrupt occurred
+
+  @retval VOID
+**/
+VOID
+EFIAPI
+TimerInterruptHandler (
+  IN EFI_EXCEPTION_TYPE  InterruptType,
+  IN EFI_SYSTEM_CONTEXT  SystemContext
+  )
+{
+  EFI_TPL  OriginalTPL;
+
+  OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);
+
+  //
+  // Clear interrupt.
+  //
+  CsrWrite (LOONGARCH_CSR_TINTCLR, 0x1);
+
+  if (mTimerNotifyFunction != NULL) {
+    //
+    // @bug : This does not handle missed timer interrupts
+    //
+    mTimerNotifyFunction (mTimerPeriod);
+  }
+
+  gBS->RestoreTPL (OriginalTPL);
+}
+
+/**
+  This function registers the handler NotifyFunction so it is called every time
+  the timer interrupt fires.  It also passes the amount of time since the last
+  handler call to the NotifyFunction.  If NotifyFunction is NULL, then the
+  handler is unregistered.  If the handler is registered, then EFI_SUCCESS is
+  returned.  If the CPU does not support registering a timer interrupt handler,
+  then EFI_UNSUPPORTED is returned.  If an attempt is made to register a handler
+  when a handler is already registered, then EFI_ALREADY_STARTED is returned.
+  If an attempt is made to unregister a handler when a handler is not registered,
+  then EFI_INVALID_PARAMETER is returned.  If an error occurs attempting to
+  register the NotifyFunction with the timer interrupt, then EFI_DEVICE_ERROR
+  is returned.
+
+  @param This             The EFI_TIMER_ARCH_PROTOCOL instance.
+  @param NotifyFunction   The function to call when a timer interrupt fires.  This
+                          function executes at TPL_HIGH_LEVEL.  The DXE Core will
+                          register a handler for the timer interrupt, so it can know
+                          how much time has passed.  This information is used to
+                          signal timer based events.  NULL will unregister the handler.
+
+  @retval        EFI_SUCCESS            The timer handler was registered.
+  @retval        EFI_UNSUPPORTED        The platform does not support timer interrupts.
+  @retval        EFI_ALREADY_STARTED    NotifyFunction is not NULL, and a handler is already
+                                        registered.
+  @retval        EFI_INVALID_PARAMETER  NotifyFunction is NULL, and a handler was not
+                                        previously registered.
+  @retval        EFI_DEVICE_ERROR       The timer handler could not be registered.
+**/
+EFI_STATUS
+EFIAPI
+TimerDriverRegisterHandler (
+  IN EFI_TIMER_ARCH_PROTOCOL  *This,
+  IN EFI_TIMER_NOTIFY         NotifyFunction
+  )
+{
+  //
+  // Check for invalid parameters
+  //
+  if ((NotifyFunction == NULL) && (mTimerNotifyFunction == NULL)) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  if ((NotifyFunction != NULL) && (mTimerNotifyFunction != NULL)) {
+    return EFI_ALREADY_STARTED;
+  }
+
+  mTimerNotifyFunction = NotifyFunction;
+
+  return EFI_SUCCESS;
+}
+
+/**
+  This function adjusts the period of timer interrupts to the value specified
+  by TimerPeriod.  If the timer period is updated, then the selected timer
+  period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned.  If
+  the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.
+  If an error occurs while attempting to update the timer period, then the
+  timer hardware will be put back in its state prior to this call, and
+  EFI_DEVICE_ERROR is returned.  If TimerPeriod is 0, then the timer interrupt
+  is disabled.  This is not the same as disabling the CPU's interrupts.
+  Instead, it must either turn off the timer hardware, or it must adjust the
+  interrupt controller so that a CPU interrupt is not generated when the timer
+  interrupt fires.
+
+  @param This            The EFI_TIMER_ARCH_PROTOCOL instance.
+  @param TimerPeriod     The rate to program the timer interrupt in 100 nS units.  If
+                         the timer hardware is not programmable, then EFI_UNSUPPORTED is
+                         returned.  If the timer is programmable, then the timer period
+                         will be rounded up to the nearest timer period that is supported
+                         by the timer hardware.  If TimerPeriod is set to 0, then the
+                         timer interrupts will be disabled.
+
+  @retval        EFI_SUCCESS       The timer period was changed.
+  @retval        EFI_UNSUPPORTED   The platform cannot change the period of the timer interrupt.
+  @retval        EFI_DEVICE_ERROR  The timer period could not be changed due to a device error.
+**/
+EFI_STATUS
+EFIAPI
+TimerDriverSetTimerPeriod (
+  IN EFI_TIMER_ARCH_PROTOCOL  *This,
+  IN UINT64                   TimerPeriod
+  )
+{
+  UINT64  TimerCount;
+
+  if (TimerPeriod == 0) {
+    //
+    // Disable timer interrupt for a TimerPeriod of 0
+    //
+    mCpu->DisableInterrupt (mCpu);
+  } else {
+    TimerCount = TimerPeriod * GetPerformanceCounterProperties (NULL, NULL) / 10000000ULL;
+
+    if (TimerCount >= BIT48) {
+      TimerCount = 0;
+    }
+
+    //
+    // Program the stable timer with the new count value
+    //
+    mTimerTicks = TimerCount;
+    SetPitCount (TimerCount);
+
+    //
+    // Enable timer interrupt
+    //
+    mCpu->EnableInterrupt (mCpu);
+  }
+
+  //
+  // Save the new timer period
+  //
+  mTimerPeriod = TimerPeriod;
+
+  return EFI_SUCCESS;
+}
+
+/**
+  This function retrieves the period of timer interrupts in 100 ns units,
+  returns that value in TimerPeriod, and returns EFI_SUCCESS.  If TimerPeriod
+  is NULL, then EFI_INVALID_PARAMETER is returned.  If a TimerPeriod of 0 is
+  returned, then the timer is currently disabled.
+
+  @param This            The EFI_TIMER_ARCH_PROTOCOL instance.
+  @param TimerPeriod     A pointer to the timer period to retrieve in 100 ns units.  If
+                         0 is returned, then the timer is currently disabled.
+
+  @retval EFI_SUCCESS            The timer period was returned in TimerPeriod.
+  @retval EFI_INVALID_PARAMETER  TimerPeriod is NULL.
+**/
+EFI_STATUS
+EFIAPI
+TimerDriverGetTimerPeriod (
+  IN EFI_TIMER_ARCH_PROTOCOL  *This,
+  OUT UINT64                  *TimerPeriod
+  )
+{
+  if (TimerPeriod == NULL) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  *TimerPeriod = mTimerPeriod;
+
+  return EFI_SUCCESS;
+}
+
+/**
+  Disable the timer
+  DXE Core will disable the timer after all the event handlers have run.
+
+  @param[in]  Event   The Event that is being processed
+  @param[in]  Context Event Context
+**/
+VOID
+EFIAPI
+ExitBootServicesEvent (
+  IN EFI_EVENT  Event,
+  IN VOID       *Context
+  )
+{
+  /*
+   * Disable timer interrupt when exiting boot service
+   */
+  CsrWrite (LOONGARCH_CSR_TMCFG, 0x0);
+}
+
+/**
+  This function generates a soft timer interrupt. If the platform does not support soft
+  timer interrupts, then EFI_UNSUPPORTED is returned. Otherwise, EFI_SUCCESS is returned.
+  If a handler has been registered through the EFI_TIMER_ARCH_PROTOCOL.RegisterHandler ()
+  service, then a soft timer interrupt will be generated. If the timer interrupt is
+  enabled when this service is called, then the registered handler will be invoked. The
+  registered handler should not be able to distinguish a hardware-generated timer
+  interrupt from a software-generated timer interrupt.
+
+  @param This              The EFI_TIMER_ARCH_PROTOCOL instance.
+
+  @retval EFI_SUCCESS       The soft timer interrupt was generated.
+  @retval EFI_UNSUPPORTED   The platform does not support the generation of soft timer interrupts.
+**/
+EFI_STATUS
+EFIAPI
+TimerDriverGenerateSoftInterrupt (
+  IN EFI_TIMER_ARCH_PROTOCOL  *This
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+  Initialize the Timer Architectural Protocol driver
+
+  @param ImageHandle     ImageHandle of the loaded driver
+  @param SystemTable     Pointer to the System Table
+
+  @retval EFI_SUCCESS            Timer Architectural Protocol created
+  @retval EFI_OUT_OF_RESOURCES   Not enough resources available to initialize driver.
+  @retval EFI_DEVICE_ERROR       A device error occurred attempting to initialize the driver.
+**/
+EFI_STATUS
+EFIAPI
+StableTimerDriverInitialize (
+  IN EFI_HANDLE        ImageHandle,
+  IN EFI_SYSTEM_TABLE  *SystemTable
+  )
+{
+  EFI_STATUS  Status;
+  UINT32      TimerVector;
+
+  //
+  // Initialize the pointer to our notify function.
+  //
+  mTimerNotifyFunction = NULL;
+
+  //
+  // Make sure the Timer Architectural Protocol is not already installed in the system
+  //
+  ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiTimerArchProtocolGuid);
+
+  //
+  // Find the CPU architectural protocol.
+  //
+  Status = gBS->LocateProtocol (&gEfiCpuArchProtocolGuid, NULL, (VOID **)&mCpu);
+  ASSERT_EFI_ERROR (Status);
+
+  //
+  // Force the timer to be disabled
+  //
+  Status = TimerDriverSetTimerPeriod (&mTimer, 0);
+  ASSERT_EFI_ERROR (Status);
+
+  //
+  // Calculate const frequence
+  //
+  DEBUG ((
+    DEBUG_INFO,
+    "===========Stable timer freq %d Hz=============\n",
+    GetPerformanceCounterProperties (NULL, NULL)
+    ));
+
+  //
+  // Install interrupt handler for Stable Timer #0 (ISA IRQ0)
+  //
+  TimerVector = EXCEPT_LOONGARCH_INT_TIMER;
+  Status      = mCpu->RegisterInterruptHandler (mCpu, TimerVector, TimerInterruptHandler);
+  ASSERT_EFI_ERROR (Status);
+
+  //
+  // Enable TI local timer interrupt
+  //
+  EnableLocalInterrupts (1 << EXCEPT_LOONGARCH_INT_TIMER);
+
+  //
+  // Force the timer to be enabled at its default period
+  //
+  Status = TimerDriverSetTimerPeriod (&mTimer, DEFAULT_TIMER_TICK_DURATION);
+  ASSERT_EFI_ERROR (Status);
+
+  //
+  // Install the Timer Architectural Protocol onto a new handle
+  //
+  Status = gBS->InstallMultipleProtocolInterfaces (
+                  &mTimerHandle,
+                  &gEfiTimerArchProtocolGuid,
+                  &mTimer,
+                  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);
+
+  return Status;
+}
diff --git a/OvmfPkg/LoongArchVirt/Drivers/StableTimerDxe/Timer.h b/OvmfPkg/LoongArchVirt/Drivers/StableTimerDxe/Timer.h
new file mode 100644
index 0000000000..5efccdfa44
--- /dev/null
+++ b/OvmfPkg/LoongArchVirt/Drivers/StableTimerDxe/Timer.h
@@ -0,0 +1,127 @@
+/** @file
+  Private data structures
+
+  Copyright (c) 2024 Loongson Technology Corporation Limited. All rights reserved.<BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef TIMER_H_
+#define TIMER_H_
+
+#include <Protocol/Timer.h>
+
+#define DEFAULT_TIMER_TICK_DURATION  100000 // 10ms = 100000 100 ns units
+
+//
+// The current period of the timer interrupt
+//
+volatile UINT64  mTimerPeriod = 0;
+volatile UINT64  mTimerTicks  = 0;
+
+/**
+  This function adjusts the period of timer interrupts to the value specified
+  by TimerPeriod.  If the timer period is updated, then the selected timer
+  period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned.  If
+  the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.
+  If an error occurs while attempting to update the timer period, then the
+  timer hardware will be put back in its state prior to this call, and
+  EFI_DEVICE_ERROR is returned.  If TimerPeriod is 0, then the timer interrupt
+  is disabled.  This is not the same as disabling the CPU's interrupts.
+  Instead, it must either turn off the timer hardware, or it must adjust the
+  interrupt controller so that a CPU interrupt is not generated when the timer
+  interrupt fires.
+
+  @param This            The EFI_TIMER_ARCH_PROTOCOL instance.
+  @param NotifyFunction  The rate to program the timer interrupt in 100 nS units.  If
+                         the timer hardware is not programmable, then EFI_UNSUPPORTED is
+                         returned.  If the timer is programmable, then the timer period
+                         will be rounded up to the nearest timer period that is supported
+                         by the timer hardware.  If TimerPeriod is set to 0, then the
+                         timer interrupts will be disabled.
+
+  @retval        EFI_SUCCESS       The timer period was changed.
+  @retval        EFI_UNSUPPORTED   The platform cannot change the period of the timer interrupt.
+  @retval        EFI_DEVICE_ERROR  The timer period could not be changed due to a device error.
+**/
+EFI_STATUS
+EFIAPI
+TimerDriverRegisterHandler (
+  IN EFI_TIMER_ARCH_PROTOCOL  *This,
+  IN EFI_TIMER_NOTIFY         NotifyFunction
+  );
+
+/**
+  This function adjusts the period of timer interrupts to the value specified
+  by TimerPeriod.  If the timer period is updated, then the selected timer
+  period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned.  If
+  the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.
+  If an error occurs while attempting to update the timer period, then the
+  timer hardware will be put back in its state prior to this call, and
+  EFI_DEVICE_ERROR is returned.  If TimerPeriod is 0, then the timer interrupt
+  is disabled.  This is not the same as disabling the CPU's interrupts.
+  Instead, it must either turn off the timer hardware, or it must adjust the
+  interrupt controller so that a CPU interrupt is not generated when the timer
+  interrupt fires.
+
+  @param This            The EFI_TIMER_ARCH_PROTOCOL instance.
+  @param TimerPeriod     The rate to program the timer interrupt in 100 nS units.  If
+                         the timer hardware is not programmable, then EFI_UNSUPPORTED is
+                         returned.  If the timer is programmable, then the timer period
+                         will be rounded up to the nearest timer period that is supported
+                         by the timer hardware.  If TimerPeriod is set to 0, then the
+                         timer interrupts will be disabled.
+
+  @retval        EFI_SUCCESS       The timer period was changed.
+  @retval        EFI_UNSUPPORTED   The platform cannot change the period of the timer interrupt.
+  @retval        EFI_DEVICE_ERROR  The timer period could not be changed due to a device error.
+**/
+EFI_STATUS
+EFIAPI
+TimerDriverSetTimerPeriod (
+  IN EFI_TIMER_ARCH_PROTOCOL  *This,
+  IN UINT64                   TimerPeriod
+  );
+
+/**
+  This function retrieves the period of timer interrupts in 100 ns units,
+  returns that value in TimerPeriod, and returns EFI_SUCCESS.  If TimerPeriod
+  is NULL, then EFI_INVALID_PARAMETER is returned.  If a TimerPeriod of 0 is
+  returned, then the timer is currently disabled.
+
+  @param This            The EFI_TIMER_ARCH_PROTOCOL instance.
+  @param TimerPeriod     A pointer to the timer period to retrieve in 100 ns units.  If
+                         0 is returned, then the timer is currently disabled.
+
+  @retval EFI_SUCCESS            The timer period was returned in TimerPeriod.
+  @retval EFI_INVALID_PARAMETER  TimerPeriod is NULL.
+**/
+EFI_STATUS
+EFIAPI
+TimerDriverGetTimerPeriod (
+  IN EFI_TIMER_ARCH_PROTOCOL  *This,
+  OUT UINT64                  *TimerPeriod
+  );
+
+/**
+  This function generates a soft timer interrupt. If the platform does not support soft
+  timer interrupts, then EFI_UNSUPPORTED is returned. Otherwise, EFI_SUCCESS is returned.
+  If a handler has been registered through the EFI_TIMER_ARCH_PROTOCOL.RegisterHandler()
+  service, then a soft timer interrupt will be generated. If the timer interrupt is
+  enabled when this service is called, then the registered handler will be invoked. The
+  registered handler should not be able to distinguish a hardware-generated timer
+  interrupt from a software-generated timer interrupt.
+
+  @param This              The EFI_TIMER_ARCH_PROTOCOL instance.
+
+  @retval EFI_SUCCESS       The soft timer interrupt was generated.
+  @retval EFI_UNSUPPORTED   The platform does not support the generation of soft timer interrupts.
+**/
+EFI_STATUS
+EFIAPI
+TimerDriverGenerateSoftInterrupt (
+  IN EFI_TIMER_ARCH_PROTOCOL  *This
+  );
+
+#endif // TIMER_H_
diff --git a/OvmfPkg/LoongArchVirt/Drivers/StableTimerDxe/TimerDxe.inf b/OvmfPkg/LoongArchVirt/Drivers/StableTimerDxe/TimerDxe.inf
new file mode 100644
index 0000000000..7548a1df46
--- /dev/null
+++ b/OvmfPkg/LoongArchVirt/Drivers/StableTimerDxe/TimerDxe.inf
@@ -0,0 +1,41 @@
+## @file
+#  Stable timer driver that provides Timer Arch protocol.
+#
+#  Copyright (c) 2024 Loongson Technology Corporation Limited. All rights reserved.<BR>
+#
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+[Defines]
+  INF_VERSION                    = 1.29
+  BASE_NAME                      = Timer
+  MODULE_UNI_FILE                = Timer.uni
+  FILE_GUID                      = AEBE2648-47A9-40FA-83FD-06AA88443BB2
+  MODULE_TYPE                    = DXE_DRIVER
+  VERSION_STRING                 = 1.0
+  ENTRY_POINT                    = StableTimerDriverInitialize
+
+#
+#  VALID_ARCHITECTURES           = LOONGARCH64
+#
+
+[Sources]
+  Timer.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+
+[LibraryClasses]
+  BaseLib
+  DebugLib
+  IoLib
+  TimerLib
+  UefiBootServicesTableLib
+  UefiDriverEntryPoint
+
+[Protocols]
+  gEfiCpuArchProtocolGuid       ## CONSUMES
+  gEfiTimerArchProtocolGuid     ## PRODUCES
+
+[depex]
+  gEfiCpuArchProtocolGuid
-- 
2.27.0



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