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Diffstat (limited to 'ReferenceCode/ME/Heci/Smm/HeciHpet.c')
| -rw-r--r-- | ReferenceCode/ME/Heci/Smm/HeciHpet.c | 282 |
1 files changed, 282 insertions, 0 deletions
diff --git a/ReferenceCode/ME/Heci/Smm/HeciHpet.c b/ReferenceCode/ME/Heci/Smm/HeciHpet.c new file mode 100644 index 0000000..2f75571 --- /dev/null +++ b/ReferenceCode/ME/Heci/Smm/HeciHpet.c @@ -0,0 +1,282 @@ +/*++ + This file contains an 'Intel Peripheral Driver' and uniquely + identified as "Intel Reference Module" and is + licensed for Intel CPUs and chipsets under the terms of your + license agreement with Intel or your vendor. This file may + be modified by the user, subject to additional terms of the + license agreement +--*/ +/*++ + +Copyright (c) 2006 - 2010 Intel Corporation. All rights reserved +This software and associated documentation (if any) is furnished +under a license and may only be used or copied in accordance +with the terms of the license. Except as permitted by such +license, no part of this software or documentation may be +reproduced, stored in a retrieval system, or transmitted in any +form or by any means without the express written consent of +Intel Corporation. + +Module Name: + + HeciHpet.c + +Abstract: + + Definitions for HECI driver + +--*/ +#include "HeciHpet.h" +#include "HeciRegs.h" +#include "HeciCore.h" + +// +// Extern for shared HECI data and protocols +// +extern HECI_INSTANCE_SMM *mHeciContext; +VOLATILE UINT32 mSaveHpetConfigReg; + +VOID +SaveHpet ( + VOID + ) +/*++ + +Routine Description: + + Store the value of High Performance Timer + +Arguments: + + None + +Returns: + + None + +--*/ +{ + mSaveHpetConfigReg = MmioRead32 (PCH_RCRB_BASE + R_PCH_RCRB_HPTC); +} + +VOID +RestoreHpet ( + VOID + ) +/*++ + +Routine Description: + + Restore the value of High Performance Timer + +Arguments: + + None + +Returns: + + None + +--*/ +{ + MmioWrite32 (PCH_RCRB_BASE + R_PCH_RCRB_HPTC, mSaveHpetConfigReg); +} + +VOID +StartTimer ( + OUT UINT32 *Start, + OUT UINT32 *End, + IN UINT32 Time + ) +/*++ + + Routine Description: + + Used for calculating timeouts + + Arguments: + + Start - Snapshot of the HPET timer + End - Calculated time when timeout period will be done + Time - Timeout period in microseconds + + Returns: + + VOID + +--*/ +{ + UINT32 Ticks; + + // + // Make sure that HPET is enabled and running + // + EnableHpet (); + + // + // Read current timer value into start time from HPET + // + *Start = mHeciContext->HpetTimer[HPET_MAIN_COUNTER_LOW]; + + // + // Convert microseconds into 70ns timer ticks + // + Ticks = Time * HPET_TICKS_PER_MICRO; + + // + // Compute end time + // + *End = *Start + Ticks; + + return ; +} + +EFI_STATUS +Timeout ( + IN UINT32 Start, + IN UINT32 End + ) +/*++ + + Routine Description: + Used to determine if a timeout has occured. + + Arguments: + Start - Snapshot of the HPET timer when the timeout period started. + End - Calculated time when timeout period will be done. + + Returns: + EFI_STATUS + +--*/ +{ + UINT32 Current; + + // + // Read HPET and assign the value as the current time. + // + Current = mHeciContext->HpetTimer[HPET_MAIN_COUNTER_LOW]; + + // + // Test basic case (no overflow) + // + if ((Start < End) && (End <= Current)) { + return EFI_TIMEOUT; + } + // + // Test basic start/end conditions with overflowed timer + // + if ((Start < End) && (Current < Start)) { + return EFI_TIMEOUT; + } + // + // Test for overflowed start/end condition + // + if ((Start > End) && ((Current < Start) && (Current > End))) { + return EFI_TIMEOUT; + } + // + // Catch corner case of broken arguments + // + if (Start == End) { + return EFI_TIMEOUT; + } + // + // Else, we have not yet timed out + // + return EFI_SUCCESS; +} + +VOID +IoDelay ( + UINT32 delayTime + ) +/*++ + +Routine Description: + + Delay for at least the request number of microseconds + +Arguments: + + delayTime - Number of microseconds to delay. + +Returns: + + None. + +--*/ +{ + SmmStall (delayTime); +} + +VOID +SmmStall ( + IN UINTN Microseconds + ) +/*++ + +Routine Description: + + Delay for at least the request number of microseconds. + Timer used is DMA refresh timer, which has 15us granularity. + You can call with any number of microseconds, but this + implementation cannot support 1us granularity. + +Arguments: + + Microseconds - Number of microseconds to delay. + +Returns: + + None + +--*/ +{ + UINT8 Data; + UINT8 InitialState; + UINTN CycleIterations; + + CycleIterations = 0; + Data = 0; + InitialState = 0; + + // + // The time-source is 15 us granular, so calibrate the timing loop + // based on this baseline + // Error is possible 15us. + // + CycleIterations = (Microseconds / 15) + 1; + + // + // Use the DMA Refresh timer in port 0x61. Cheap but effective. + // The only issue is that the granularity is 15us, and we want to + // guarantee "at least" one full transition to avoid races. + // + // + // _____________/----------\__________/-------- + // + // |<--15us-->| + // + // --------------------------------------------------> Time (us) + // + while (CycleIterations--) { + Data = IoRead8 (0x61); + InitialState = Data; + + // + // Capture first transition (strictly less than one period) + // + while (InitialState == Data) { + Data = IoRead8 (0x61); + } + + InitialState = Data; + // + // Capture next transition (guarantee at least one full pulse) + // + while (InitialState == Data) { + Data = IoRead8 (0x61); + } + } +} |