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In the current implementation we only use very high priority interrupts (levels 0, 0x10 and 0x20 in CORTEX-M speak) but that means there are loads of lower priority ones that are effectively unused. I have *not* changed the semantics of these levels but have 'shifted' them to be based around the midpoint of the available interrupts (0x80) rather than at the top end....that allows for interrupts to be defined above (or, indeed, below) them as needed by the application. This should have no functional effect on existing code but adds in a clean capability to define higher priority interrupts.
This commit is contained in:
committed by
Gregory Nutt
parent
8aeeb1d8d3
commit
d0cda60442
@@ -77,53 +77,4 @@
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#define NVIC_SYSH_PRIORITY_MAX 0x00 /* Zero is maximum priority */
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#define NVIC_SYSH_PRIORITY_STEP 0x20 /* Three bits of interrupt priority used */
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/* If CONFIG_ARMV7M_USEBASEPRI is selected, then interrupts will be disabled
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* by setting the BASEPRI register to NVIC_SYSH_DISABLE_PRIORITY so that most
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* interrupts will not have execution priority. SVCall must have execution
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* priority in all cases.
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*
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* In the normal cases, interrupts are not nest-able and all interrupts run
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* at an execution priority between NVIC_SYSH_PRIORITY_MIN and
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* NVIC_SYSH_PRIORITY_MAX (with NVIC_SYSH_PRIORITY_MAX reserved for SVCall).
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*
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* If, in addition, CONFIG_ARCH_HIPRI_INTERRUPT is defined, then special
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* high priority interrupts are supported. These are not "nested" in the
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* normal sense of the word. These high priority interrupts can interrupt
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* normal processing but execute outside of OS (although they can "get back
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* into the game" via a PendSV interrupt).
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*
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* In the normal course of things, interrupts must occasionally be disabled
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* using the up_irq_save() inline function to prevent contention in use of
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* resources that may be shared between interrupt level and non-interrupt
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* level logic. Now the question arises, if CONFIG_ARCH_HIPRI_INTERRUPT,
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* do we disable all interrupts (except SVCall), or do we only disable the
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* "normal" interrupts. Since the high priority interrupts cannot interact
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* with the OS, you may want to permit the high priority interrupts even if
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* interrupts are disabled. The setting CONFIG_ARCH_INT_DISABLEALL can be
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* used to select either behavior:
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*
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* ----------------------------+--------------+----------------------------
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* CONFIG_ARCH_HIPRI_INTERRUPT | NO | YES
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* ----------------------------+--------------+--------------+-------------
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* CONFIG_ARCH_INT_DISABLEALL | N/A | YES | NO
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* ----------------------------+--------------+--------------+-------------
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* | | | SVCall
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* | SVCall | SVCall | HIGH
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* Disable here and below --------> MAXNORMAL ---> HIGH --------> MAXNORMAL
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* | | MAXNORMAL |
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* ----------------------------+--------------+--------------+-------------
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*/
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#if defined(CONFIG_ARCH_HIPRI_INTERRUPT) && defined(CONFIG_ARCH_INT_DISABLEALL)
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# define NVIC_SYSH_MAXNORMAL_PRIORITY (NVIC_SYSH_PRIORITY_MAX + 2*NVIC_SYSH_PRIORITY_STEP)
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# define NVIC_SYSH_HIGH_PRIORITY (NVIC_SYSH_PRIORITY_MAX + NVIC_SYSH_PRIORITY_STEP)
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# define NVIC_SYSH_DISABLE_PRIORITY NVIC_SYSH_HIGH_PRIORITY
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# define NVIC_SYSH_SVCALL_PRIORITY NVIC_SYSH_PRIORITY_MAX
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#else
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# define NVIC_SYSH_MAXNORMAL_PRIORITY (NVIC_SYSH_PRIORITY_MAX + NVIC_SYSH_PRIORITY_STEP)
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# define NVIC_SYSH_HIGH_PRIORITY NVIC_SYSH_PRIORITY_MAX
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# define NVIC_SYSH_DISABLE_PRIORITY NVIC_SYSH_MAXNORMAL_PRIORITY
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# define NVIC_SYSH_SVCALL_PRIORITY NVIC_SYSH_PRIORITY_MAX
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#endif
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#endif /* __ARCH_ARM_INCLUDE_EFM32_CHIP_H */
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