82 lines
4.0 KiB
C
82 lines
4.0 KiB
C
/************************************************************************************
|
|
* arch/arm/include/armv7-m/nvicpri.h
|
|
*
|
|
* Licensed to the Apache Software Foundation (ASF) under one or more
|
|
* contributor license agreements. See the NOTICE file distributed with
|
|
* this work for additional information regarding copyright ownership. The
|
|
* ASF licenses this file to you under the Apache License, Version 2.0 (the
|
|
* "License"); you may not use this file except in compliance with the
|
|
* License. You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
|
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
|
* License for the specific language governing permissions and limitations
|
|
* under the License.
|
|
*
|
|
************************************************************************************/
|
|
|
|
#ifndef __ARCH_ARM_INCLUDE_ARM7_M_NVICPRI_H
|
|
#define __ARCH_ARM_INCLUDE_ARM7_M_NVICPRI_H
|
|
|
|
/************************************************************************************
|
|
* Included Files
|
|
************************************************************************************/
|
|
|
|
#include <arch/chip/chip.h>
|
|
|
|
/************************************************************************************
|
|
* Pre-processor Definitions
|
|
************************************************************************************/
|
|
|
|
/* If CONFIG_ARMV7M_USEBASEPRI is selected, then interrupts will be disabled
|
|
* by setting the BASEPRI register to NVIC_SYSH_DISABLE_PRIORITY so that most
|
|
* interrupts will not have execution priority. SVCall must have execution
|
|
* priority in all cases.
|
|
*
|
|
* In the normal cases, interrupts are not nest-able and all interrupts run
|
|
* at an execution priority between NVIC_SYSH_PRIORITY_MIN and
|
|
* NVIC_SYSH_PRIORITY_MAX (with NVIC_SYSH_PRIORITY_MAX reserved for SVCall).
|
|
*
|
|
* If, in addition, CONFIG_ARCH_HIPRI_INTERRUPT is defined, then special
|
|
* high priority interrupts are supported. These are not "nested" in the
|
|
* normal sense of the word. These high priority interrupts can interrupt
|
|
* normal processing but execute outside of OS (although they can "get back
|
|
* into the game" via a PendSV interrupt).
|
|
*
|
|
* In the normal course of things, interrupts must occasionally be disabled
|
|
* using the up_irq_save() inline function to prevent contention in use of
|
|
* resources that may be shared between interrupt level and non-interrupt
|
|
* level logic. Now the question arises, if we are using
|
|
* CONFIG_ARCH_HIPRI_INTERRUPT=y, do we disable all interrupts except
|
|
* SVCall (we cannot disable SVCall interrupts). Or do we only disable the
|
|
* "normal" interrupts?
|
|
*
|
|
* If we are using the BASEPRI register to disable interrupts, then the
|
|
* answer is that we must disable ONLY the "normal interrupts". That
|
|
* is because we cannot disable SVCALL interrupts and we cannot permit
|
|
* SVCAll interrupts running at a higher priority than the high priority
|
|
* interrupts (otherwise, they will introduce jitter in the high priority
|
|
* interrupt response time.)
|
|
*
|
|
* Hence, if you need to disable the high priority interrupt, you will have
|
|
* to disable the interrupt either at the peripheral that generates the
|
|
* interrupt or at the NVIC. Disabling global interrupts via the BASEPRI
|
|
* register cannot effect high priority interrupts.
|
|
*/
|
|
|
|
/* The high priority interrupt must be highest priority. This prevents
|
|
* SVCALL handling from adding jitter to high priority interrupt response.
|
|
* Disabling interrupts will disable all interrupts EXCEPT SVCALL and the
|
|
* high priority interrupts.
|
|
*/
|
|
|
|
#define NVIC_SYSH_MAXNORMAL_PRIORITY NVIC_SYSH_PRIORITY_DEFAULT
|
|
#define NVIC_SYSH_HIGH_PRIORITY (NVIC_SYSH_PRIORITY_DEFAULT - 2*NVIC_SYSH_PRIORITY_STEP)
|
|
#define NVIC_SYSH_DISABLE_PRIORITY NVIC_SYSH_PRIORITY_DEFAULT
|
|
#define NVIC_SYSH_SVCALL_PRIORITY (NVIC_SYSH_PRIORITY_DEFAULT - 1*NVIC_SYSH_PRIORITY_STEP)
|
|
|
|
#endif /* __ARCH_ARM_INCLUDE_ARM7_M_NVICPRI_H */
|