cpu/cortexm_common: Add atomic_utils_arch.h

cpu/cortexm_common/include/atomic_utils_arch.h

@@ -0,0 +1,193 @@
+/*
+ * Copyright (C) 2020 Otto-von-Guericke-Universität Magdeburg
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser General
+ * Public License v2.1. See the file LICENSE in the top level directory for more
+ * details.
+ */
+
+/**
+ * @ingroup     cpu_cortexm_common
+ *
+ * @{
+ *
+ * @file
+ * @brief       Implementation of fast atomic utility functions
+ * @author      Marian Buschsieweke <marian.buschsieweke@ovgu.de>
+ */
+
+#ifndef ATOMIC_UTILS_ARCH_H
+#define ATOMIC_UTILS_ARCH_H
+#ifndef DOXYGEN
+
+#include "bit.h"
+#include "periph_cpu.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* clang provides no built-in atomic access to regular variables */
+#ifndef __clang__
+
+#define HAS_ATOMIC_LOAD_U8
+static inline uint8_t atomic_load_u8(const uint8_t *var)
+{
+    return __atomic_load_1(var, __ATOMIC_SEQ_CST);
+}
+
+#define HAS_ATOMIC_LOAD_U16
+static inline uint16_t atomic_load_u16(const uint16_t *var)
+{
+    return __atomic_load_2(var, __ATOMIC_SEQ_CST);
+}
+
+#define HAS_ATOMIC_LOAD_U32
+static inline uint32_t atomic_load_u32(const uint32_t *var)
+{
+    return __atomic_load_4(var, __ATOMIC_SEQ_CST);
+}
+
+#define HAS_ATOMIC_STORE_U8
+static inline void atomic_store_u8(uint8_t *dest, uint8_t val)
+{
+    __atomic_store_1(dest, val, __ATOMIC_SEQ_CST);
+}
+
+#define HAS_ATOMIC_STORE_U16
+static inline void atomic_store_u16(uint16_t *dest, uint16_t val)
+{
+    __atomic_store_2(dest, val, __ATOMIC_SEQ_CST);
+}
+
+#define HAS_ATOMIC_STORE_U32
+static inline void atomic_store_u32(uint32_t *dest, uint32_t val)
+{
+    __atomic_store_4(dest, val, __ATOMIC_SEQ_CST);
+}
+
+#endif /* __clang__ */
+
+#if CPU_HAS_BITBAND
+#define HAS_ATOMIC_BIT
+
+typedef volatile uint32_t *atomic_bit_u8_t;
+typedef volatile uint32_t *atomic_bit_u16_t;
+typedef volatile uint32_t *atomic_bit_u32_t;
+typedef volatile uint32_t *atomic_bit_u64_t;
+
+static inline void __attribute__((always_inline)) _bit_barrier_pre(void)
+{
+    __asm__ volatile ("" : : : "memory");
+}
+
+static inline void __attribute__((always_inline)) _bit_barrier_post(void)
+{
+    __asm__ volatile ("" : : : "memory");
+}
+
+static inline bool _is_addr_valid_for_bitbanding(void *_addr)
+{
+    /* SRAM bit-band region goes from 0x20000000 to 0x200fffff,
+     * peripheral bit-band region goes from 0x40000000 to 0x400fffff */
+    uintptr_t addr = (uintptr_t)_addr;
+    if ((addr < 0x20000000UL) || (addr > 0x400fffffUL)) {
+        return false;
+    }
+
+    if ((addr >= 0x200fffffUL) && (addr < 0x40000000UL)) {
+        return false;
+    }
+
+    return true;
+}
+
+static inline atomic_bit_u8_t atomic_bit_u8(uint8_t *dest, uint8_t bit)
+{
+    assert(_is_addr_valid_for_bitbanding(dest));
+    return bitband_addr(dest, bit);
+}
+
+static inline atomic_bit_u16_t atomic_bit_u16(uint16_t *dest, uint8_t bit)
+{
+    assert(_is_addr_valid_for_bitbanding(dest));
+    return bitband_addr(dest, bit);
+}
+
+static inline atomic_bit_u32_t atomic_bit_u32(uint32_t *dest, uint8_t bit)
+{
+    assert(_is_addr_valid_for_bitbanding(dest));
+    return bitband_addr(dest, bit);
+}
+
+static inline atomic_bit_u64_t atomic_bit_u64(uint64_t *dest, uint8_t bit)
+{
+    assert(_is_addr_valid_for_bitbanding(dest));
+    return bitband_addr(dest, bit);
+}
+
+static inline void atomic_set_bit_u8(atomic_bit_u8_t bit)
+{
+    _bit_barrier_pre();
+    *bit = 1;
+    _bit_barrier_post();
+}
+
+static inline void atomic_set_bit_u16(atomic_bit_u16_t bit)
+{
+    _bit_barrier_pre();
+    *bit = 1;
+    _bit_barrier_post();
+}
+
+static inline void atomic_set_bit_u32(atomic_bit_u32_t bit)
+{
+    _bit_barrier_pre();
+    *bit = 1;
+    _bit_barrier_post();
+}
+
+static inline void atomic_set_bit_u64(atomic_bit_u64_t bit)
+{
+    _bit_barrier_pre();
+    *bit = 1;
+    _bit_barrier_post();
+}
+
+static inline void atomic_clear_bit_u8(atomic_bit_u8_t bit)
+{
+    _bit_barrier_pre();
+    *bit = 0;
+    _bit_barrier_post();
+}
+static inline void atomic_clear_bit_u16(atomic_bit_u16_t bit)
+{
+    _bit_barrier_pre();
+    *bit = 0;
+    _bit_barrier_post();
+}
+
+static inline void atomic_clear_bit_u32(atomic_bit_u32_t bit)
+{
+    _bit_barrier_pre();
+    *bit = 0;
+    _bit_barrier_post();
+}
+
+static inline void atomic_clear_bit_u64(atomic_bit_u64_t bit)
+{
+    _bit_barrier_pre();
+    *bit = 0;
+    _bit_barrier_post();
+}
+
+
+#endif /* CPU_HAS_BITBAND */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* DOXYGEN */
+#endif /* ATOMIC_UTILS_ARCH_H */
+/** @} */