NRF51_DK: Add Critical Section HAL implementation

Author: Steven Cartmell

features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_MCU_NRF51822/hal_patch/critical_section_api.c

@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2015-2017, 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 "cmsis.h"
+#include "nrf_error.h"
+#include "nrf_sdm.h"
+#include "nrf_soc.h"
+
+#include <stdbool.h>
+#include <stdint.h>
+
+static union {
+    uint32_t _PRIMASK_state;
+    uint8_t _sd_state;
+} _state = {0};
+
+static bool _use_softdevice_routine = false;
+
+void hal_critical_section_enter(void)
+{
+    // Fetch the current state of interrupts
+    uint32_t primask = __get_PRIMASK();
+
+    // If interrupts are enabled, try to use the soft device
+    uint8_t sd_enabled;
+    if ((primask == 0) &&
+        (sd_softdevice_is_enabled(&sd_enabled) == NRF_SUCCESS) &&
+        (sd_enabled == 1)) {
+        // If the softdevice can be used, use it.
+        sd_nvic_critical_region_enter(&_state._sd_state);
+        _use_softdevice_routine = true;
+    } else {
+        // If interrupts are enabled, disable them.
+        if (primask == 0) {
+            __disable_irq();
+        }
+
+        // Store PRIMASK state, it will be restored when exiting critical
+        // section.
+        _state._PRIMASK_state = primask;
+        _use_softdevice_routine = false;
+    }
+}
+
+void hal_critical_section_exit(void)
+{
+    // Restore the state as it was prior to entering the critical section.
+    if (_use_softdevice_routine) {
+        sd_nvic_critical_region_exit(_state._sd_state)
+    } else {
+        __set_PRIMASK(_state._PRIMASK_state);
+    }
+}

features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_MCU_NRF51822/hal_patch/nordic_critical.c

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2015-2017, 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 "nrf_nvic.h"
+
+#include <stdint.h> // uint32_t, UINT32_MAX
+
+static uint8_t _sd_state = 0;
+
+void hal_critical_section_enter(void)
+{
+    sd_nvic_critical_region_enter(&_sd_state);
+}
+
+void hal_critical_section_exit(void)
+{
+    sd_nvic_critical_region_exit(_sd_state);
+}