Diff: platform/mbed_critical.c

Revision:

149:156823d33999

diff -r 21d94c44109e -r 156823d33999 platform/mbed_critical.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/platform/mbed_critical.c	Fri Oct 28 11:17:30 2016 +0100
@@ -0,0 +1,320 @@
+/*
+ * Copyright (c) 2015-2016, ARM Limited, All Rights Reserved
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed 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.
+ */
+
+#include "platform/critical.h"
+
+#include "cmsis.h"
+#include "platform/mbed_assert.h"
+#include "platform/toolchain.h"
+
+#define EXCLUSIVE_ACCESS (!defined (__CORTEX_M0) && !defined (__CORTEX_M0PLUS))
+
+static volatile uint32_t interrupt_enable_counter = 0;
+static volatile bool critical_interrupts_disabled = false;
+
+bool core_util_are_interrupts_enabled(void)
+{
+#if defined(__CORTEX_A9)
+    return ((__get_CPSR() & 0x80) == 0);
+#else
+    return ((__get_PRIMASK() & 0x1) == 0);
+#endif
+}
+
+MBED_WEAK void core_util_critical_section_enter(void)
+{
+    bool interrupts_disabled = !core_util_are_interrupts_enabled();
+    __disable_irq();
+
+    /* Save the interrupt disabled state as it was prior to any nested critical section lock use */
+    if (!interrupt_enable_counter) {
+        critical_interrupts_disabled = interrupts_disabled;
+    }
+
+    /* If the interrupt_enable_counter overflows or we are in a nested critical section and interrupts
+       are enabled, then something has gone badly wrong thus assert an error.
+    */
+    MBED_ASSERT(interrupt_enable_counter < UINT32_MAX); 
+// FIXME
+#ifndef   FEATURE_UVISOR
+    if (interrupt_enable_counter > 0) {
+        MBED_ASSERT(interrupts_disabled);
+    }
+#else
+#warning "core_util_critical_section_enter needs fixing to work from unprivileged code"
+#endif /* FEATURE_UVISOR */
+    interrupt_enable_counter++;
+}
+
+MBED_WEAK void core_util_critical_section_exit(void)
+{
+    /* If critical_section_enter has not previously been called, do nothing */
+    if (interrupt_enable_counter) {
+
+// FIXME
+#ifndef   FEATURE_UVISOR
+        bool interrupts_disabled = !core_util_are_interrupts_enabled(); /* get the current interrupt disabled state */
+
+        MBED_ASSERT(interrupts_disabled); /* Interrupts must be disabled on invoking an exit from a critical section */
+#else
+#warning "core_util_critical_section_exit needs fixing to work from unprivileged code"
+#endif /* FEATURE_UVISOR */
+
+        interrupt_enable_counter--;
+
+        /* Only re-enable interrupts if we are exiting the last of the nested critical sections and
+           interrupts were enabled on entry to the first critical section.
+        */
+        if (!interrupt_enable_counter && !critical_interrupts_disabled) {
+            __enable_irq();
+        }
+    }
+}
+
+#if EXCLUSIVE_ACCESS
+
+/* Supress __ldrex and __strex deprecated warnings - "#3731-D: intrinsic is deprecated" */
+#if defined (__CC_ARM) 
+#pragma diag_suppress 3731
+#endif
+
+bool core_util_atomic_cas_u8(uint8_t *ptr, uint8_t *expectedCurrentValue, uint8_t desiredValue)
+{
+    uint8_t currentValue = __LDREXB((volatile uint8_t*)ptr);
+    if (currentValue != *expectedCurrentValue) {
+        *expectedCurrentValue = currentValue;
+        __CLREX();
+        return false;
+    }
+
+    return !__STREXB(desiredValue, (volatile uint8_t*)ptr);
+}
+
+bool core_util_atomic_cas_u16(uint16_t *ptr, uint16_t *expectedCurrentValue, uint16_t desiredValue)
+{
+    uint16_t currentValue = __LDREXH((volatile uint16_t*)ptr);
+    if (currentValue != *expectedCurrentValue) {
+        *expectedCurrentValue = currentValue;
+        __CLREX();
+        return false;
+    }
+
+    return !__STREXH(desiredValue, (volatile uint16_t*)ptr);
+}
+
+
+bool core_util_atomic_cas_u32(uint32_t *ptr, uint32_t *expectedCurrentValue, uint32_t desiredValue)
+{
+    uint32_t currentValue = __LDREXW((volatile uint32_t*)ptr);
+    if (currentValue != *expectedCurrentValue) {
+        *expectedCurrentValue = currentValue;
+        __CLREX();
+        return false;
+    }
+
+    return !__STREXW(desiredValue, (volatile uint32_t*)ptr);
+}
+
+uint8_t core_util_atomic_incr_u8(uint8_t *valuePtr, uint8_t delta)
+{
+    uint8_t newValue;
+    do {
+        newValue = __LDREXB((volatile uint8_t*)valuePtr) + delta;
+    } while (__STREXB(newValue, (volatile uint8_t*)valuePtr));
+    return newValue;
+}
+
+uint16_t core_util_atomic_incr_u16(uint16_t *valuePtr, uint16_t delta)
+{
+    uint16_t newValue;
+    do {
+        newValue = __LDREXH((volatile uint16_t*)valuePtr) + delta;
+    } while (__STREXH(newValue, (volatile uint16_t*)valuePtr));
+    return newValue;
+}
+
+uint32_t core_util_atomic_incr_u32(uint32_t *valuePtr, uint32_t delta)
+{
+    uint32_t newValue;
+    do {
+        newValue = __LDREXW((volatile uint32_t*)valuePtr) + delta;
+    } while (__STREXW(newValue, (volatile uint32_t*)valuePtr));
+    return newValue;
+}
+
+
+uint8_t core_util_atomic_decr_u8(uint8_t *valuePtr, uint8_t delta)
+{
+    uint8_t newValue;
+    do {
+        newValue = __LDREXB((volatile uint8_t*)valuePtr) - delta;
+    } while (__STREXB(newValue, (volatile uint8_t*)valuePtr));
+    return newValue;
+}
+
+uint16_t core_util_atomic_decr_u16(uint16_t *valuePtr, uint16_t delta)
+{
+    uint16_t newValue;
+    do {
+        newValue = __LDREXH((volatile uint16_t*)valuePtr) - delta;
+    } while (__STREXH(newValue, (volatile uint16_t*)valuePtr));
+    return newValue;
+}
+
+uint32_t core_util_atomic_decr_u32(uint32_t *valuePtr, uint32_t delta)
+{
+    uint32_t newValue;
+    do {
+        newValue = __LDREXW((volatile uint32_t*)valuePtr) - delta;
+    } while (__STREXW(newValue, (volatile uint32_t*)valuePtr));
+    return newValue;
+}
+
+#else
+
+bool core_util_atomic_cas_u8(uint8_t *ptr, uint8_t *expectedCurrentValue, uint8_t desiredValue)
+{
+    bool success;
+    uint8_t currentValue;
+    core_util_critical_section_enter();
+    currentValue = *ptr;
+    if (currentValue == *expectedCurrentValue) {
+        *ptr = desiredValue;
+        success = true;
+    } else {
+        *expectedCurrentValue = currentValue;
+        success = false;
+    }
+    core_util_critical_section_exit();
+    return success;
+}
+
+bool core_util_atomic_cas_u16(uint16_t *ptr, uint16_t *expectedCurrentValue, uint16_t desiredValue)
+{
+    bool success;
+    uint16_t currentValue;
+    core_util_critical_section_enter();
+    currentValue = *ptr;
+    if (currentValue == *expectedCurrentValue) {
+        *ptr = desiredValue;
+        success = true;
+    } else {
+        *expectedCurrentValue = currentValue;
+        success = false;
+    }
+    core_util_critical_section_exit();
+    return success;
+}
+
+
+bool core_util_atomic_cas_u32(uint32_t *ptr, uint32_t *expectedCurrentValue, uint32_t desiredValue)
+{
+    bool success;
+    uint32_t currentValue;
+    core_util_critical_section_enter();
+    currentValue = *ptr;
+    if (currentValue == *expectedCurrentValue) {
+        *ptr = desiredValue;
+        success = true;
+    } else {
+        *expectedCurrentValue = currentValue;
+        success = false;
+    }
+    core_util_critical_section_exit();
+    return success;
+}
+
+
+uint8_t core_util_atomic_incr_u8(uint8_t *valuePtr, uint8_t delta)
+{
+    uint8_t newValue;
+    core_util_critical_section_enter();
+    newValue = *valuePtr + delta;
+    *valuePtr = newValue;
+    core_util_critical_section_exit();
+    return newValue;
+}
+
+uint16_t core_util_atomic_incr_u16(uint16_t *valuePtr, uint16_t delta)
+{
+    uint16_t newValue;
+    core_util_critical_section_enter();
+    newValue = *valuePtr + delta;
+    *valuePtr = newValue;
+    core_util_critical_section_exit();
+    return newValue;
+}
+
+uint32_t core_util_atomic_incr_u32(uint32_t *valuePtr, uint32_t delta)
+{
+    uint32_t newValue;
+    core_util_critical_section_enter();
+    newValue = *valuePtr + delta;
+    *valuePtr = newValue;
+    core_util_critical_section_exit();
+    return newValue;
+}
+
+
+uint8_t core_util_atomic_decr_u8(uint8_t *valuePtr, uint8_t delta)
+{
+    uint8_t newValue;
+    core_util_critical_section_enter();
+    newValue = *valuePtr - delta;
+    *valuePtr = newValue;
+    core_util_critical_section_exit();
+    return newValue;
+}
+
+uint16_t core_util_atomic_decr_u16(uint16_t *valuePtr, uint16_t delta)
+{
+    uint16_t newValue;
+    core_util_critical_section_enter();
+    newValue = *valuePtr - delta;
+    *valuePtr = newValue;
+    core_util_critical_section_exit();
+    return newValue;
+}
+
+uint32_t core_util_atomic_decr_u32(uint32_t *valuePtr, uint32_t delta)
+{
+    uint32_t newValue;
+    core_util_critical_section_enter();
+    newValue = *valuePtr - delta;
+    *valuePtr = newValue;
+    core_util_critical_section_exit();
+    return newValue;
+}
+
+#endif
+
+
+bool core_util_atomic_cas_ptr(void **ptr, void **expectedCurrentValue, void *desiredValue) {
+    return core_util_atomic_cas_u32(
+            (uint32_t *)ptr,
+            (uint32_t *)expectedCurrentValue,
+            (uint32_t)desiredValue);
+}
+
+void *core_util_atomic_incr_ptr(void **valuePtr, ptrdiff_t delta) {
+    return (void *)core_util_atomic_incr_u32((uint32_t *)valuePtr, (uint32_t)delta);
+}
+
+void *core_util_atomic_decr_ptr(void **valuePtr, ptrdiff_t delta) {
+    return (void *)core_util_atomic_decr_u32((uint32_t *)valuePtr, (uint32_t)delta);
+}
+