RISC-V: Device, timer, IRQs, and the SBI

This patch contains code that interfaces with devices that are mandated
by the RISC-V supervisor specification and that don't have explicit
drivers anywhere else in the tree.  This includes the staticly defined
interrupts, the CSR-mapped timer, and virtualized SBI devices.

Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>

1 files changed, 63 insertions, 0 deletions

diff --git a/arch/riscv/include/asm/irqflags.h b/arch/riscv/include/asm/irqflags.h
new file mode 100644
index 000000000000..6fdc860d7f84
--- /dev/null
+++ b/arch/riscv/include/asm/irqflags.h
@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2012 Regents of the University of California
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ */
+
+
+#ifndef _ASM_RISCV_IRQFLAGS_H
+#define _ASM_RISCV_IRQFLAGS_H
+
+#include <asm/processor.h>
+#include <asm/csr.h>
+
+/* read interrupt enabled status */
+static inline unsigned long arch_local_save_flags(void)
+{
+	return csr_read(sstatus);
+}
+
+/* unconditionally enable interrupts */
+static inline void arch_local_irq_enable(void)
+{
+	csr_set(sstatus, SR_IE);
+}
+
+/* unconditionally disable interrupts */
+static inline void arch_local_irq_disable(void)
+{
+	csr_clear(sstatus, SR_IE);
+}
+
+/* get status and disable interrupts */
+static inline unsigned long arch_local_irq_save(void)
+{
+	return csr_read_clear(sstatus, SR_IE);
+}
+
+/* test flags */
+static inline int arch_irqs_disabled_flags(unsigned long flags)
+{
+	return !(flags & SR_IE);
+}
+
+/* test hardware interrupt enable bit */
+static inline int arch_irqs_disabled(void)
+{
+	return arch_irqs_disabled_flags(arch_local_save_flags());
+}
+
+/* set interrupt enabled status */
+static inline void arch_local_irq_restore(unsigned long flags)
+{
+	csr_set(sstatus, flags & SR_IE);
+}
+
+#endif /* _ASM_RISCV_IRQFLAGS_H */