mbed_critical.c

00001 /*
00002  * Copyright (c) 2015-2016, ARM Limited, All Rights Reserved
00003  * SPDX-License-Identifier: Apache-2.0
00004  *
00005  * Licensed under the Apache License, Version 2.0 (the "License"); you may
00006  * not use this file except in compliance with the License.
00007  * You may obtain a copy of the License at
00008  *
00009  * http://www.apache.org/licenses/LICENSE-2.0
00010  *
00011  * Unless required by applicable law or agreed to in writing, software
00012  * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
00013  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00014  * See the License for the specific language governing permissions and
00015  * limitations under the License.
00016  */
00017 
00018 /* Declare __STDC_LIMIT_MACROS so stdint.h defines UINT32_MAX when using C++ */
00019 #define __STDC_LIMIT_MACROS
00020 #include "hal/critical_section_api.h"
00021 
00022 #include "cmsis.h"
00023 #include "platform/mbed_assert.h"
00024 #include "platform/mbed_critical.h"
00025 #include "platform/mbed_toolchain.h"
00026 
00027 // if __EXCLUSIVE_ACCESS rtx macro not defined, we need to get this via own-set architecture macros
00028 #ifndef MBED_EXCLUSIVE_ACCESS
00029 #ifndef __EXCLUSIVE_ACCESS
00030 #if ((__ARM_ARCH_7M__      == 1U) || \
00031     (__ARM_ARCH_7EM__     == 1U) || \
00032     (__ARM_ARCH_8M_BASE__ == 1U) || \
00033     (__ARM_ARCH_8M_MAIN__ == 1U)) || \
00034     (__ARM_ARCH_7A__ == 1U)
00035 #define MBED_EXCLUSIVE_ACCESS      1U
00036 #elif (__ARM_ARCH_6M__ == 1U)
00037 #define MBED_EXCLUSIVE_ACCESS      0U
00038 #else
00039 #error "Unknown architecture for exclusive access"
00040 #endif
00041 #else
00042 #define MBED_EXCLUSIVE_ACCESS __EXCLUSIVE_ACCESS
00043 #endif
00044 #endif
00045 
00046 static volatile uint32_t critical_section_reentrancy_counter = 0;
00047 
00048 bool core_util_are_interrupts_enabled(void)
00049 {
00050 #if defined(__CORTEX_A9)
00051     return ((__get_CPSR() & 0x80) == 0);
00052 #else
00053     return ((__get_PRIMASK() & 0x1) == 0);
00054 #endif
00055 }
00056 
00057 bool core_util_is_isr_active(void)
00058 {
00059 #if defined(__CORTEX_A9)
00060     switch (__get_CPSR() & 0x1FU) {
00061         case CPSR_M_USR:
00062         case CPSR_M_SYS:
00063             return false;
00064         case CPSR_M_SVC:
00065         default:
00066             return true;
00067     }
00068 #else
00069     return (__get_IPSR() != 0U);
00070 #endif
00071 }
00072 
00073 bool core_util_in_critical_section(void)
00074 {
00075     return hal_in_critical_section();
00076 }
00077 
00078 void core_util_critical_section_enter(void)
00079 {
00080     // If the reentrancy counter overflows something has gone badly wrong.
00081     MBED_ASSERT(critical_section_reentrancy_counter < UINT32_MAX);
00082 
00083     hal_critical_section_enter();
00084 
00085     ++critical_section_reentrancy_counter;
00086 }
00087 
00088 void core_util_critical_section_exit(void)
00089 {
00090 
00091     // If critical_section_enter has not previously been called, do nothing
00092     if (critical_section_reentrancy_counter == 0) {
00093         return;
00094     }
00095 
00096     --critical_section_reentrancy_counter;
00097 
00098     if (critical_section_reentrancy_counter == 0) {
00099         hal_critical_section_exit();
00100     }
00101 }
00102 
00103 void core_util_atomic_flag_clear(volatile core_util_atomic_flag *flagPtr)
00104 {
00105     flagPtr->_flag = false;
00106 }
00107 
00108 #if MBED_EXCLUSIVE_ACCESS
00109 
00110 /* Supress __ldrex and __strex deprecated warnings - "#3731-D: intrinsic is deprecated" */
00111 #if defined (__CC_ARM)
00112 #pragma diag_suppress 3731
00113 #endif
00114 
00115 bool core_util_atomic_flag_test_and_set(volatile core_util_atomic_flag *flagPtr)
00116 {
00117     uint8_t currentValue;
00118     do {
00119         currentValue = __LDREXB(&flagPtr->_flag);
00120     } while (__STREXB(true, &flagPtr->_flag));
00121     return currentValue;
00122 }
00123 
00124 bool core_util_atomic_cas_u8(volatile uint8_t *ptr, uint8_t *expectedCurrentValue, uint8_t desiredValue)
00125 {
00126     do {
00127         uint8_t currentValue = __LDREXB(ptr);
00128         if (currentValue != *expectedCurrentValue) {
00129             *expectedCurrentValue = currentValue;
00130             __CLREX();
00131             return false;
00132         }
00133     } while (__STREXB(desiredValue, ptr));
00134     return true;
00135 }
00136 
00137 bool core_util_atomic_cas_u16(volatile uint16_t *ptr, uint16_t *expectedCurrentValue, uint16_t desiredValue)
00138 {
00139     do {
00140         uint16_t currentValue = __LDREXH(ptr);
00141         if (currentValue != *expectedCurrentValue) {
00142             *expectedCurrentValue = currentValue;
00143             __CLREX();
00144             return false;
00145         }
00146     } while (__STREXH(desiredValue, ptr));
00147     return true;
00148 }
00149 
00150 
00151 bool core_util_atomic_cas_u32(volatile uint32_t *ptr, uint32_t *expectedCurrentValue, uint32_t desiredValue)
00152 {
00153     do {
00154         uint32_t currentValue = __LDREXW(ptr);
00155         if (currentValue != *expectedCurrentValue) {
00156             *expectedCurrentValue = currentValue;
00157             __CLREX();
00158             return false;
00159         }
00160     } while (__STREXW(desiredValue, ptr));
00161     return true;
00162 }
00163 
00164 uint8_t core_util_atomic_incr_u8(volatile uint8_t *valuePtr, uint8_t delta)
00165 {
00166     uint8_t newValue;
00167     do {
00168         newValue = __LDREXB(valuePtr) + delta;
00169     } while (__STREXB(newValue, valuePtr));
00170     return newValue;
00171 }
00172 
00173 uint16_t core_util_atomic_incr_u16(volatile uint16_t *valuePtr, uint16_t delta)
00174 {
00175     uint16_t newValue;
00176     do {
00177         newValue = __LDREXH(valuePtr) + delta;
00178     } while (__STREXH(newValue, valuePtr));
00179     return newValue;
00180 }
00181 
00182 uint32_t core_util_atomic_incr_u32(volatile uint32_t *valuePtr, uint32_t delta)
00183 {
00184     uint32_t newValue;
00185     do {
00186         newValue = __LDREXW(valuePtr) + delta;
00187     } while (__STREXW(newValue, valuePtr));
00188     return newValue;
00189 }
00190 
00191 
00192 uint8_t core_util_atomic_decr_u8(volatile uint8_t *valuePtr, uint8_t delta)
00193 {
00194     uint8_t newValue;
00195     do {
00196         newValue = __LDREXB(valuePtr) - delta;
00197     } while (__STREXB(newValue, valuePtr));
00198     return newValue;
00199 }
00200 
00201 uint16_t core_util_atomic_decr_u16(volatile uint16_t *valuePtr, uint16_t delta)
00202 {
00203     uint16_t newValue;
00204     do {
00205         newValue = __LDREXH(valuePtr) - delta;
00206     } while (__STREXH(newValue, valuePtr));
00207     return newValue;
00208 }
00209 
00210 uint32_t core_util_atomic_decr_u32(volatile uint32_t *valuePtr, uint32_t delta)
00211 {
00212     uint32_t newValue;
00213     do {
00214         newValue = __LDREXW(valuePtr) - delta;
00215     } while (__STREXW(newValue, valuePtr));
00216     return newValue;
00217 }
00218 
00219 #else
00220 
00221 bool core_util_atomic_flag_test_and_set(volatile core_util_atomic_flag *flagPtr)
00222 {
00223     core_util_critical_section_enter();
00224     uint8_t currentValue = flagPtr->_flag;
00225     flagPtr->_flag = true;
00226     core_util_critical_section_exit();
00227     return currentValue;
00228 }
00229 
00230 bool core_util_atomic_cas_u8(volatile uint8_t *ptr, uint8_t *expectedCurrentValue, uint8_t desiredValue)
00231 {
00232     bool success;
00233     uint8_t currentValue;
00234     core_util_critical_section_enter();
00235     currentValue = *ptr;
00236     if (currentValue == *expectedCurrentValue) {
00237         *ptr = desiredValue;
00238         success = true;
00239     } else {
00240         *expectedCurrentValue = currentValue;
00241         success = false;
00242     }
00243     core_util_critical_section_exit();
00244     return success;
00245 }
00246 
00247 bool core_util_atomic_cas_u16(volatile uint16_t *ptr, uint16_t *expectedCurrentValue, uint16_t desiredValue)
00248 {
00249     bool success;
00250     uint16_t currentValue;
00251     core_util_critical_section_enter();
00252     currentValue = *ptr;
00253     if (currentValue == *expectedCurrentValue) {
00254         *ptr = desiredValue;
00255         success = true;
00256     } else {
00257         *expectedCurrentValue = currentValue;
00258         success = false;
00259     }
00260     core_util_critical_section_exit();
00261     return success;
00262 }
00263 
00264 
00265 bool core_util_atomic_cas_u32(volatile uint32_t *ptr, uint32_t *expectedCurrentValue, uint32_t desiredValue)
00266 {
00267     bool success;
00268     uint32_t currentValue;
00269     core_util_critical_section_enter();
00270     currentValue = *ptr;
00271     if (currentValue == *expectedCurrentValue) {
00272         *ptr = desiredValue;
00273         success = true;
00274     } else {
00275         *expectedCurrentValue = currentValue;
00276         success = false;
00277     }
00278     core_util_critical_section_exit();
00279     return success;
00280 }
00281 
00282 
00283 uint8_t core_util_atomic_incr_u8(volatile uint8_t *valuePtr, uint8_t delta)
00284 {
00285     uint8_t newValue;
00286     core_util_critical_section_enter();
00287     newValue = *valuePtr + delta;
00288     *valuePtr = newValue;
00289     core_util_critical_section_exit();
00290     return newValue;
00291 }
00292 
00293 uint16_t core_util_atomic_incr_u16(volatile uint16_t *valuePtr, uint16_t delta)
00294 {
00295     uint16_t newValue;
00296     core_util_critical_section_enter();
00297     newValue = *valuePtr + delta;
00298     *valuePtr = newValue;
00299     core_util_critical_section_exit();
00300     return newValue;
00301 }
00302 
00303 uint32_t core_util_atomic_incr_u32(volatile uint32_t *valuePtr, uint32_t delta)
00304 {
00305     uint32_t newValue;
00306     core_util_critical_section_enter();
00307     newValue = *valuePtr + delta;
00308     *valuePtr = newValue;
00309     core_util_critical_section_exit();
00310     return newValue;
00311 }
00312 
00313 
00314 uint8_t core_util_atomic_decr_u8(volatile uint8_t *valuePtr, uint8_t delta)
00315 {
00316     uint8_t newValue;
00317     core_util_critical_section_enter();
00318     newValue = *valuePtr - delta;
00319     *valuePtr = newValue;
00320     core_util_critical_section_exit();
00321     return newValue;
00322 }
00323 
00324 uint16_t core_util_atomic_decr_u16(volatile uint16_t *valuePtr, uint16_t delta)
00325 {
00326     uint16_t newValue;
00327     core_util_critical_section_enter();
00328     newValue = *valuePtr - delta;
00329     *valuePtr = newValue;
00330     core_util_critical_section_exit();
00331     return newValue;
00332 }
00333 
00334 uint32_t core_util_atomic_decr_u32(volatile uint32_t *valuePtr, uint32_t delta)
00335 {
00336     uint32_t newValue;
00337     core_util_critical_section_enter();
00338     newValue = *valuePtr - delta;
00339     *valuePtr = newValue;
00340     core_util_critical_section_exit();
00341     return newValue;
00342 }
00343 
00344 #endif
00345 
00346 
00347 bool core_util_atomic_cas_ptr(void *volatile *ptr, void **expectedCurrentValue, void *desiredValue)
00348 {
00349     return core_util_atomic_cas_u32(
00350                (volatile uint32_t *)ptr,
00351                (uint32_t *)expectedCurrentValue,
00352                (uint32_t)desiredValue);
00353 }
00354 
00355 void *core_util_atomic_incr_ptr(void *volatile *valuePtr, ptrdiff_t delta)
00356 {
00357     return (void *)core_util_atomic_incr_u32((volatile uint32_t *)valuePtr, (uint32_t)delta);
00358 }
00359 
00360 void *core_util_atomic_decr_ptr(void *volatile *valuePtr, ptrdiff_t delta)
00361 {
00362     return (void *)core_util_atomic_decr_u32((volatile uint32_t *)valuePtr, (uint32_t)delta);
00363 }
00364