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riscv: don't use the rdtime(h) pseudo-instructions

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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 <hch@lst.de>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
This commit is contained in:
Christoph Hellwig
2019-08-21 23:58:36 +09:00
committed by Paul Walmsley
parent f5bf645d10
commit 2f12dbf190
2 changed files with 25 additions and 36 deletions
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44
arch/riscv/include/asm/timex.h
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@@ -6,43 +6,41 @@
#ifndef _ASM_RISCV_TIMEX_H
#define _ASM_RISCV_TIMEX_H
#include <asm/param.h>
#include <asm/csr.h>
typedef unsigned long cycles_t;
static inline cycles_t get_cycles_inline(void)
static inline cycles_t get_cycles(void)
{
cycles_t n;
__asm__ __volatile__ (
"rdtime %0"
: "=r" (n));
return n;
return csr_read(CSR_TIME);
}
#define get_cycles get_cycles_inline
#define get_cycles get_cycles
#ifdef CONFIG_64BIT
static inline uint64_t get_cycles64(void)
static inline u64 get_cycles64(void)
{
return get_cycles();
return get_cycles();
}
#else
static inline uint64_t get_cycles64(void)
#else /* CONFIG_64BIT */
static inline u32 get_cycles_hi(void)
{
u32 lo, hi, tmp;
__asm__ __volatile__ (
"1:\n"
"rdtimeh %0\n"
"rdtime %1\n"
"rdtimeh %2\n"
"bne %0, %2, 1b"
: "=&r" (hi), "=&r" (lo), "=&r" (tmp));
return csr_read(CSR_TIMEH);
}
static inline u64 get_cycles64(void)
{
u32 hi, lo;
do {
hi = get_cycles_hi();
lo = get_cycles();
} while (hi != get_cycles_hi());
return ((u64)hi << 32) | lo;
}
#endif
#endif /* CONFIG_64BIT */
#define ARCH_HAS_READ_CURRENT_TIMER
static inline int read_current_timer(unsigned long *timer_val)
{
*timer_val = get_cycles();