diff options
Diffstat (limited to 'PcAtChipsetPkg/8254TimerDxe/Timer.c')
| -rw-r--r-- | PcAtChipsetPkg/8254TimerDxe/Timer.c | 479 |
1 files changed, 479 insertions, 0 deletions
diff --git a/PcAtChipsetPkg/8254TimerDxe/Timer.c b/PcAtChipsetPkg/8254TimerDxe/Timer.c new file mode 100644 index 000000000..2874301bb --- /dev/null +++ b/PcAtChipsetPkg/8254TimerDxe/Timer.c @@ -0,0 +1,479 @@ +/*++
+
+Copyright (c) 2005 - 2006, Intel 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.
+
+
+Module Name:
+
+ Timer.c
+
+Abstract:
+
+ Timer Architectural Protocol as defined in the DXE CIS
+
+--*/
+
+#include "Timer.h"
+
+//
+// The handle onto which the Timer Architectural Protocol will be installed
+//
+EFI_HANDLE mTimerHandle = 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;
+
+//
+// Pointer to the Legacy 8259 Protocol instance
+//
+EFI_LEGACY_8259_PROTOCOL *mLegacy8259;
+
+//
+// The notification function to call on every timer interrupt.
+// A bug in the compiler prevents us from initializing this here.
+//
+EFI_TIMER_NOTIFY mTimerNotifyFunction;
+
+//
+// The current period of the timer interrupt
+//
+volatile UINT64 mTimerPeriod = 0;
+
+//
+// Worker Functions
+//
+VOID
+SetPitCount (
+ IN UINT16 Count
+ )
+/*++
+
+Routine Description:
+
+ Sets the counter value for Timer #0 in a legacy 8254 timer.
+
+Arguments:
+
+ Count - The 16-bit counter value to program into Timer #0 of the legacy 8254 timer.
+
+Returns:
+
+ None
+
+--*/
+{
+ IoWrite8 (TIMER_CONTROL_PORT, 0x36);
+ IoWrite8 (TIMER0_COUNT_PORT, (UINT8)(Count & 0xff));
+ IoWrite8 (TIMER0_COUNT_PORT, (UINT8)((Count >> 8) & 0xff));
+}
+
+VOID
+EFIAPI
+TimerInterruptHandler (
+ IN EFI_EXCEPTION_TYPE InterruptType,
+ IN EFI_SYSTEM_CONTEXT SystemContext
+ )
+/*++
+
+Routine Description:
+
+ 8254 Timer #0 Interrupt Handler
+
+Arguments:
+
+ InterruptType - The type of interrupt that occured
+
+ SystemContext - A pointer to the system context when the interrupt occured
+
+Returns:
+
+ None
+
+--*/
+{
+ EFI_TPL OriginalTPL;
+
+ OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);
+
+ mLegacy8259->EndOfInterrupt (mLegacy8259, Efi8259Irq0);
+
+ if (mTimerNotifyFunction) {
+ //
+ // BUGBUG : This does not handle missed timer interrupts
+ //
+ mTimerNotifyFunction (mTimerPeriod);
+ }
+
+ gBS->RestoreTPL (OriginalTPL);
+}
+
+EFI_STATUS
+EFIAPI
+TimerDriverRegisterHandler (
+ IN EFI_TIMER_ARCH_PROTOCOL *This,
+ IN EFI_TIMER_NOTIFY NotifyFunction
+ )
+/*++
+
+Routine Description:
+
+ 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.
+
+Arguments:
+
+ This - The EFI_TIMER_ARCH_PROTOCOL instance.
+
+ 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.
+
+Returns:
+
+ EFI_SUCCESS - The timer handler was registered.
+
+ EFI_UNSUPPORTED - The platform does not support timer interrupts.
+
+ EFI_ALREADY_STARTED - NotifyFunction is not NULL, and a handler is already
+ registered.
+
+ EFI_INVALID_PARAMETER - NotifyFunction is NULL, and a handler was not
+ previously registered.
+
+ EFI_DEVICE_ERROR - The timer handler could not be registered.
+
+--*/
+{
+ //
+ // 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;
+}
+
+EFI_STATUS
+EFIAPI
+TimerDriverSetTimerPeriod (
+ IN EFI_TIMER_ARCH_PROTOCOL *This,
+ IN UINT64 TimerPeriod
+ )
+/*++
+
+Routine Description:
+
+ 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.
+
+Arguments:
+
+ This - The EFI_TIMER_ARCH_PROTOCOL instance.
+
+ 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.
+
+Returns:
+
+ EFI_SUCCESS - The timer period was changed.
+
+ EFI_UNSUPPORTED - The platform cannot change the period of the timer interrupt.
+
+ EFI_DEVICE_ERROR - The timer period could not be changed due to a device error.
+
+--*/
+{
+ UINT64 TimerCount;
+
+ //
+ // The basic clock is 1.19318 MHz or 0.119318 ticks per 100 ns.
+ // TimerPeriod * 0.119318 = 8254 timer divisor. Using integer arithmetic
+ // TimerCount = (TimerPeriod * 119318)/1000000.
+ //
+ // Round up to next highest integer. This guarantees that the timer is
+ // equal to or slightly longer than the requested time.
+ // TimerCount = ((TimerPeriod * 119318) + 500000)/1000000
+ //
+ // Note that a TimerCount of 0 is equivalent to a count of 65,536
+ //
+ // Since TimerCount is limited to 16 bits for IA32, TimerPeriod is limited
+ // to 20 bits.
+ //
+ if (TimerPeriod == 0) {
+ //
+ // Disable timer interrupt for a TimerPeriod of 0
+ //
+ mLegacy8259->DisableIrq (mLegacy8259, Efi8259Irq0);
+ } else {
+
+ //
+ // Convert TimerPeriod into 8254 counts
+ //
+ TimerCount = DivU64x32 (MultU64x32 (119318, (UINT32) TimerPeriod) + 500000, 1000000);
+
+ //
+ // Check for overflow
+ //
+ if (TimerCount >= 65536) {
+ TimerCount = 0;
+ if (TimerPeriod >= DEFAULT_TIMER_TICK_DURATION) {
+ TimerPeriod = DEFAULT_TIMER_TICK_DURATION;
+ }
+ }
+ //
+ // Program the 8254 timer with the new count value
+ //
+ SetPitCount ((UINT16) TimerCount);
+
+ //
+ // Enable timer interrupt
+ //
+ mLegacy8259->EnableIrq (mLegacy8259, Efi8259Irq0, FALSE);
+ }
+ //
+ // Save the new timer period
+ //
+ mTimerPeriod = TimerPeriod;
+
+ return EFI_SUCCESS;
+}
+
+EFI_STATUS
+EFIAPI
+TimerDriverGetTimerPeriod (
+ IN EFI_TIMER_ARCH_PROTOCOL *This,
+ OUT UINT64 *TimerPeriod
+ )
+/*++
+
+Routine Description:
+
+ 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.
+
+Arguments:
+
+ This - The EFI_TIMER_ARCH_PROTOCOL instance.
+
+ TimerPeriod - A pointer to the timer period to retrieve in 100 ns units. If
+ 0 is returned, then the timer is currently disabled.
+
+Returns:
+
+ EFI_SUCCESS - The timer period was returned in TimerPeriod.
+
+ EFI_INVALID_PARAMETER - TimerPeriod is NULL.
+
+--*/
+{
+ if (TimerPeriod == NULL) {
+ return EFI_INVALID_PARAMETER;
+ }
+
+ *TimerPeriod = mTimerPeriod;
+
+ return EFI_SUCCESS;
+}
+
+EFI_STATUS
+EFIAPI
+TimerDriverGenerateSoftInterrupt (
+ IN EFI_TIMER_ARCH_PROTOCOL *This
+ )
+/*++
+
+Routine Description:
+
+ 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.
+
+Arguments:
+
+ This - The EFI_TIMER_ARCH_PROTOCOL instance.
+
+Returns:
+
+ EFI_SUCCESS - The soft timer interrupt was generated.
+
+ EFI_UNSUPPORTEDT - The platform does not support the generation of soft timer interrupts.
+
+--*/
+{
+ EFI_STATUS Status;
+ UINT16 IRQMask;
+ EFI_TPL OriginalTPL;
+
+ //
+ // If the timer interrupt is enabled, then the registered handler will be invoked.
+ //
+ Status = mLegacy8259->GetMask (mLegacy8259, NULL, NULL, &IRQMask, NULL);
+ ASSERT_EFI_ERROR (Status);
+ if ((IRQMask & 0x1) == 0) {
+ //
+ // Invoke the registered handler
+ //
+ OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);
+
+ if (mTimerNotifyFunction) {
+ //
+ // BUGBUG : This does not handle missed timer interrupts
+ //
+ mTimerNotifyFunction (mTimerPeriod);
+ }
+
+ gBS->RestoreTPL (OriginalTPL);
+ } else {
+ return EFI_UNSUPPORTED;
+ }
+
+ return EFI_SUCCESS;
+}
+
+EFI_STATUS
+EFIAPI
+TimerDriverInitialize (
+ IN EFI_HANDLE ImageHandle,
+ IN EFI_SYSTEM_TABLE *SystemTable
+ )
+/*++
+
+Routine Description:
+
+ Initialize the Timer Architectural Protocol driver
+
+Arguments:
+
+ ImageHandle - ImageHandle of the loaded driver
+
+ SystemTable - Pointer to the System Table
+
+Returns:
+
+ EFI_SUCCESS - Timer Architectural Protocol created
+
+ EFI_OUT_OF_RESOURCES - Not enough resources available to initialize driver.
+
+ EFI_DEVICE_ERROR - A device error occured attempting to initialize the driver.
+
+--*/
+{
+ 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);
+
+ //
+ // Find the Legacy8259 protocol.
+ //
+ Status = gBS->LocateProtocol (&gEfiLegacy8259ProtocolGuid, NULL, (VOID **) &mLegacy8259);
+ ASSERT_EFI_ERROR (Status);
+
+ //
+ // Force the timer to be disabled
+ //
+ Status = TimerDriverSetTimerPeriod (&mTimer, 0);
+ ASSERT_EFI_ERROR (Status);
+
+ //
+ // Get the interrupt vector number corresponding to IRQ0 from the 8259 driver
+ //
+ TimerVector = 0;
+ Status = mLegacy8259->GetVector (mLegacy8259, Efi8259Irq0, (UINT8 *) &TimerVector);
+ ASSERT_EFI_ERROR (Status);
+
+ //
+ // Install interrupt handler for 8254 Timer #0 (ISA IRQ0)
+ //
+ Status = mCpu->RegisterInterruptHandler (mCpu, TimerVector, TimerInterruptHandler);
+ ASSERT_EFI_ERROR (Status);
+
+ //
+ // 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);
+
+ return Status;
+}
+
|