[374] | 1 | /* mbed Microcontroller Library
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| 2 | * Copyright (c) 2017 ARM Limited
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| 3 | *
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| 4 | * Licensed under the Apache License, Version 2.0 (the "License");
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| 5 | * you may not use this file except in compliance with the License.
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| 6 | * You may obtain a copy of the License at
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| 7 | *
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| 8 | * http://www.apache.org/licenses/LICENSE-2.0
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| 9 | *
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| 10 | * Unless required by applicable law or agreed to in writing, software
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| 11 | * distributed under the License is distributed on an "AS IS" BASIS,
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| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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| 13 | * See the License for the specific language governing permissions and
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| 14 | * limitations under the License.
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| 15 | */
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| 16 | #include "cmsis.h"
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| 17 | #include "hal/critical_section_api.h"
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| 18 | #include "platform/mbed_assert.h"
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| 19 | #include "platform/mbed_toolchain.h"
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| 20 |
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| 21 | #include <stdbool.h>
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| 22 |
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| 23 | static volatile bool critical_interrupts_enabled = false;
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| 24 | static volatile bool state_saved = false;
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| 25 |
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| 26 | static bool are_interrupts_enabled(void)
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| 27 | {
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| 28 | #if defined(__CORTEX_A9)
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| 29 | return ((__get_CPSR() & 0x80) == 0);
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| 30 | #else
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| 31 | return ((__get_PRIMASK() & 0x1) == 0);
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| 32 | #endif
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| 33 | }
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| 34 |
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| 35 |
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| 36 | MBED_WEAK void hal_critical_section_enter(void)
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| 37 | {
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| 38 | const bool interrupt_state = are_interrupts_enabled();
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| 39 |
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| 40 | __disable_irq();
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| 41 |
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| 42 | if (state_saved == true) {
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| 43 | return;
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| 44 | }
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| 45 |
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| 46 | critical_interrupts_enabled = interrupt_state;
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| 47 | state_saved = true;
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| 48 | }
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| 49 |
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| 50 | MBED_WEAK void hal_critical_section_exit(void)
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| 51 | {
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| 52 | // Interrupts must be disabled on invoking an exit from a critical section
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| 53 | MBED_ASSERT(!are_interrupts_enabled());
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| 54 | state_saved = false;
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| 55 |
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| 56 | // Restore the IRQs to their state prior to entering the critical section
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| 57 | if (critical_interrupts_enabled == true) {
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| 58 | __enable_irq();
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| 59 | }
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| 60 | }
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| 61 |
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| 62 | MBED_WEAK bool hal_in_critical_section(void)
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| 63 | {
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| 64 | return (state_saved == true);
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| 65 | }
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