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Commit 757ab98

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mcb30mcb30
committedMay 4, 2016
[efi] Use a timer event to generate the currticks() timer
We currently use the EFI_CPU_ARCH_PROTOCOL's GetTimerValue() method to generate the currticks() timer, calibrated against a 1ms delay from the boot services Stall() method. This does not work on ARM platforms, where GetTimerValue() is an empty stub which just returns EFI_UNSUPPORTED. Fix by instead creating a periodic timer event, and using this event to increment a current tick counter. Signed-off-by: Michael Brown <mcb30@ipxe.org>
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‎src/include/ipxe/efi/Protocol/Cpu.h

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‎src/include/ipxe/efi/efi_timer.h

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@@ -15,4 +15,22 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
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#define TIMER_PREFIX_efi __efi_
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#endif
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/**
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* Number of ticks per second
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*
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* This is a policy decision.
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*/
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#define EFI_TICKS_PER_SEC 20
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/**
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* Get number of ticks per second
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*
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* @ret ticks_per_sec Number of ticks per second
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*/
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static inline __attribute__ (( always_inline )) unsigned long
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TIMER_INLINE ( efi, ticks_per_sec ) ( void ) {
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return EFI_TICKS_PER_SEC;
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}
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#endif /* _IPXE_EFI_TIMER_H */

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