1 files changed, 82 insertions, 0 deletions
diff --git a/src/arch/riscv/include/bits/bitops.h b/src/arch/riscv/include/bits/bitops.h
new file mode 100644
index 000000000..2019db99a
--- /dev/null
+++ b/src/arch/riscv/include/bits/bitops.h
@@ -0,0 +1,82 @@
+#ifndef _BITS_BITOPS_H
+#define _BITS_BITOPS_H
+
+/** @file
+ *
+ * RISC-V bit operations
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <stdint.h>
+
+/**
+ * Test and set bit atomically
+ *
+ * @v bit		Bit to set
+ * @v bits		Bit field
+ * @ret old		Old value of bit (zero or non-zero)
+ */
+static inline __attribute__ (( always_inline )) int
+test_and_set_bit ( unsigned int bit, volatile void *bits ) {
+	unsigned int index = ( bit / 32 );
+	unsigned int offset = ( bit % 32 );
+	volatile uint32_t *word = ( ( ( volatile uint32_t * ) bits ) + index );
+	uint32_t mask = ( 1U << offset );
+	uint32_t old;
+
+	__asm__ __volatile__ ( "amoor.w %0, %2, %1"
+			       : "=r" ( old ), "+A" ( *word )
+			       : "r" ( mask ) );
+
+	return ( !! ( old & mask ) );
+}
+
+/**
+ * Test and clear bit atomically
+ *
+ * @v bit		Bit to set
+ * @v bits		Bit field
+ * @ret old		Old value of bit (zero or non-zero)
+ */
+static inline __attribute__ (( always_inline )) int
+test_and_clear_bit ( unsigned int bit, volatile void *bits ) {
+	unsigned int index = ( bit / 32 );
+	unsigned int offset = ( bit % 32 );
+	volatile uint32_t *word = ( ( ( volatile uint32_t * ) bits ) + index );
+	uint32_t mask = ( 1U << offset );
+	uint32_t old;
+
+	__asm__ __volatile__ ( "amoand.w %0, %2, %1"
+			       : "=r" ( old ), "+A" ( *word )
+			       : "r" ( ~mask ) );
+
+	return ( !! ( old & mask ) );
+}
+
+/**
+ * Set bit atomically
+ *
+ * @v bit		Bit to set
+ * @v bits		Bit field
+ */
+static inline __attribute__ (( always_inline )) void
+set_bit ( unsigned int bit, volatile void *bits ) {
+
+	test_and_set_bit ( bit, bits );
+}
+
+/**
+ * Clear bit atomically
+ *
+ * @v bit		Bit to set
+ * @v bits		Bit field
+ */
+static inline __attribute__ (( always_inline )) void
+clear_bit ( unsigned int bit, volatile void *bits ) {
+
+	test_and_clear_bit ( bit, bits );
+}
+
+#endif /* _BITS_BITOPS_H */