mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-27 04:47:05 +00:00
d5be89a8d1
The K210 doesn't implement rdtime in M-mode, and since that's where Linux runs in the NOMMU systems that means we can't use rdtime. The K210 is the only system that anyone is currently running NOMMU or M-mode on, so here we're just inlining the timer read directly. This also adds the CLINT driver as an !MMU dependency, as it's currently the only timer driver availiable for these systems and without it we get a build failure for some configurations. Tested-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
26 lines
797 B
C
26 lines
797 B
C
/* SPDX-License-Identifier: GPL-2.0-only */
|
|
/*
|
|
* Copyright (C) 2020 Google, Inc
|
|
*/
|
|
|
|
#ifndef _ASM_RISCV_CLINT_H
|
|
#define _ASM_RISCV_CLINT_H
|
|
|
|
#include <linux/types.h>
|
|
#include <asm/mmio.h>
|
|
|
|
#ifdef CONFIG_RISCV_M_MODE
|
|
/*
|
|
* This lives in the CLINT driver, but is accessed directly by timex.h to avoid
|
|
* any overhead when accessing the MMIO timer.
|
|
*
|
|
* The ISA defines mtime as a 64-bit memory-mapped register that increments at
|
|
* a constant frequency, but it doesn't define some other constraints we depend
|
|
* on (most notably ordering constraints, but also some simpler stuff like the
|
|
* memory layout). Thus, this is called "clint_time_val" instead of something
|
|
* like "riscv_mtime", to signify that these non-ISA assumptions must hold.
|
|
*/
|
|
extern u64 __iomem *clint_time_val;
|
|
#endif
|
|
|
|
#endif
|