diff options
author | Christoph Hellwig <hch@lst.de> | 2019-08-21 23:58:36 +0900 |
---|---|---|
committer | Paul Walmsley <paul.walmsley@sifive.com> | 2019-09-05 01:52:46 -0700 |
commit | 2f12dbf190d97dc0f2f8a07269dd0d8060808539 (patch) | |
tree | d699e8fc51c7814904c0ab79c50a7144e243d544 /arch/riscv | |
parent | f5bf645d10f2c6cc85294021af70f2b7bcc42d8e (diff) | |
download | linux-2f12dbf190d97dc0f2f8a07269dd0d8060808539.tar.bz2 |
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 <hch@lst.de>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Diffstat (limited to 'arch/riscv')
-rw-r--r-- | arch/riscv/include/asm/timex.h | 44 |
1 files changed, 21 insertions, 23 deletions
diff --git a/arch/riscv/include/asm/timex.h b/arch/riscv/include/asm/timex.h index 6a703ec9d796..c7ef131b9e4c 100644 --- a/arch/riscv/include/asm/timex.h +++ b/arch/riscv/include/asm/timex.h @@ -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(); +} +#else /* CONFIG_64BIT */ +static inline u32 get_cycles_hi(void) { - return get_cycles(); + return csr_read(CSR_TIMEH); } -#else -static inline uint64_t get_cycles64(void) + +static inline u64 get_cycles64(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)); + 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(); |