1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Copyright (C) 2020 Google, Inc
4  */
5 
6 #ifndef _ASM_RISCV_CLINT_H
7 #define _ASM_RISCV_CLINT_H
8 
9 #include <linux/types.h>
10 #include <asm/mmio.h>
11 
12 #ifdef CONFIG_RISCV_M_MODE
13 /*
14  * This lives in the CLINT driver, but is accessed directly by timex.h to avoid
15  * any overhead when accessing the MMIO timer.
16  *
17  * The ISA defines mtime as a 64-bit memory-mapped register that increments at
18  * a constant frequency, but it doesn't define some other constraints we depend
19  * on (most notably ordering constraints, but also some simpler stuff like the
20  * memory layout).  Thus, this is called "clint_time_val" instead of something
21  * like "riscv_mtime", to signify that these non-ISA assumptions must hold.
22  */
23 extern u64 __iomem *clint_time_val;
24 #endif
25 
26 #endif
27