From 2f12dbf190d97dc0f2f8a07269dd0d8060808539 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 21 Aug 2019 23:58:36 +0900 Subject: riscv: don't use the rdtime(h) pseudo-instructions If we just use the CSRs that these map to directly the code is simpler and doesn't require extra inline assembly code. Also fix up the top-level comment in timer-riscv.c to not talk about the cycle count or mention details of the clocksource interface, of which this file is just a consumer. Signed-off-by: Christoph Hellwig Reviewed-by: Atish Patra Signed-off-by: Paul Walmsley --- drivers/clocksource/timer-riscv.c | 17 ++++------------- 1 file changed, 4 insertions(+), 13 deletions(-) (limited to 'drivers/clocksource/timer-riscv.c') diff --git a/drivers/clocksource/timer-riscv.c b/drivers/clocksource/timer-riscv.c index 09e031176bc6..470c7ef02ea4 100644 --- a/drivers/clocksource/timer-riscv.c +++ b/drivers/clocksource/timer-riscv.c @@ -2,6 +2,10 @@ /* * Copyright (C) 2012 Regents of the University of California * Copyright (C) 2017 SiFive + * + * All RISC-V systems have a timer attached to every hart. These timers can be + * read from the "time" and "timeh" CSRs, and can use the SBI to setup + * events. */ #include #include @@ -12,19 +16,6 @@ #include #include -/* - * All RISC-V systems have a timer attached to every hart. These timers can be - * read by the 'rdcycle' pseudo instruction, and can use the SBI to setup - * events. In order to abstract the architecture-specific timer reading and - * setting functions away from the clock event insertion code, we provide - * function pointers to the clockevent subsystem that perform two basic - * operations: rdtime() reads the timer on the current CPU, and - * next_event(delta) sets the next timer event to 'delta' cycles in the future. - * As the timers are inherently a per-cpu resource, these callbacks perform - * operations on the current hart. There is guaranteed to be exactly one timer - * per hart on all RISC-V systems. - */ - static int riscv_clock_next_event(unsigned long delta, struct clock_event_device *ce) { -- cgit