cpu/fe310: migrate to inlined irq API

Co-authored-by: Marian Buschsieweke <marian.buschsieweke@ovgu.de>

cpu/fe310/include/cpu_conf.h

@@ -39,6 +39,11 @@
  */
 #define HAVE_HEAP_STATS
 
+/**
+ * @brief   This arch uses the inlined irq API.
+ */
+#define IRQ_API_INLINED     (1)
+
 #ifdef __cplusplus
 extern "C" {
 #endif

cpu/fe310/include/irq_arch.h

@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2017 Ken Rabold
+ *               2020 Inria
+ *               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_fe310
+ * @{
+ *
+ * @file
+ * @brief           Implementation of the kernels irq interface
+ *
+ * @author          Ken Rabold
+ * @author          Alexandre Abadie <alexandre.abadie@inria.fr>
+ * @author          Marian Buschsieweke <marian.buschsieweke@ovgu.de>
+ */
+
+#ifndef IRQ_ARCH_H
+#define IRQ_ARCH_H
+
+#include <stdint.h>
+#include "irq.h"
+#include "cpu_conf.h"
+#include "cpu.h"
+
+#include "vendor/encoding.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern volatile int fe310_in_isr;
+
+/**
+ * @brief Enable all maskable interrupts
+ */
+static inline __attribute__((always_inline)) unsigned int irq_enable(void)
+{
+    /* Enable all interrupts */
+    unsigned state;
+    __asm__ volatile (
+        "csrrs %[dest], mstatus, %[mask]"
+        : [dest]    "=r"(state)
+        : [mask]    "i"(MSTATUS_MIE)
+        : "memory"
+    );
+    return state;
+}
+
+/**
+ * @brief Disable all maskable interrupts
+ */
+static inline __attribute__((always_inline)) unsigned int irq_disable(void)
+{
+
+    unsigned int state;
+    __asm__ volatile (
+        "csrrc %[dest], mstatus, %[mask]"
+        : [dest]    "=r"(state)
+        : [mask]    "i"(MSTATUS_MIE)
+        : "memory"
+    );
+
+    return state;
+}
+
+/**
+ * @brief Restore the state of the IRQ flags
+ */
+static inline __attribute__((always_inline)) void irq_restore(unsigned int state)
+{
+    /* Restore all interrupts to given state */
+    __asm__ volatile (
+        "csrw mstatus, %[state]"
+        : /* no outputs */
+        : [state]   "r"(state)
+        : "memory"
+    );
+}
+
+/**
+ * @brief See if the current context is inside an ISR
+ */
+static inline __attribute__((always_inline)) int irq_is_in(void)
+{
+    return fe310_in_isr;
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* IRQ_ARCH_H */
+/** @} */

cpu/fe310/irq_arch.c

@@ -23,6 +23,7 @@
 
 #include "cpu.h"
 #include "irq.h"
+#include "irq_arch.h"
 #include "panic.h"
 #include "sched.h"
 
@@ -74,45 +75,6 @@ void irq_init(void)
     set_csr(mstatus, MSTATUS_DEFAULT);
 }
 
-/**
- * @brief Enable all maskable interrupts
- */
-unsigned int irq_enable(void)
-{
-    /* Enable all interrupts */
-    set_csr(mstatus, MSTATUS_MIE);
-    return read_csr(mstatus);
-}
-
-/**
- * @brief Disable all maskable interrupts
- */
-unsigned int irq_disable(void)
-{
-    unsigned int state = read_csr(mstatus);
-
-    /* Disable all interrupts */
-    clear_csr(mstatus, MSTATUS_MIE);
-    return state;
-}
-
-/**
- * @brief Restore the state of the IRQ flags
- */
-void irq_restore(unsigned int state)
-{
-    /* Restore all interrupts to given state */
-    write_csr(mstatus, state);
-}
-
-/**
- * @brief See if the current context is inside an ISR
- */
-int irq_is_in(void)
-{
-    return fe310_in_isr;
-}
-
 /**
  * @brief   Set External ISR callback
  */