Re: [Minios-devel] [PATCH 34/40] arm64: implement the timer helpers for arm64

[Julien Grall <julien.grall@xxxxxxxxxx>]

Hi Shijie,

On 03/11/17 03:12, Huang Shijie wrote:
> Implement the timer helpers:
>     read_virtual_count/write_timer_ctl/set_vtimer_compare(empty)
>
> Change-Id: I8ec2bd775f726e93ee9bcf24239c610e4bccfbe5
> Jira: ENTOS-247
> Signed-off-by: Huang Shijie <shijie.huang@xxxxxxx>
> ---
>   arch/arm/time.c | 14 ++++++++++++++
>   1 file changed, 14 insertions(+)
>
> diff --git a/arch/arm/time.c b/arch/arm/time.c
> index 0e68a4f..32d9c59 100644
> --- a/arch/arm/time.c
> +++ b/arch/arm/time.c
> @@ -58,9 +58,15 @@ static struct timespec shadow_ts;
>   
>   static inline uint64_t read_virtual_count(void)
>   {
> +#if defined(__arm__)
>       uint32_t c_lo, c_hi;
>       __asm__ __volatile__("mrrc p15, 1, %0, %1, c14":"=r"(c_lo), "=r"(c_hi));
>       return (((uint64_t) c_hi) << 32) + c_lo;
> +#elif defined(__aarch64__)
> +    uint64_t c;
> +    __asm__ __volatile__("mrs %0, cntvct_el0":"=r"(c));
> +    return c;
> +#endif
I think it is time to introduce helpers reading a 
system-register/co-processors. This will be much nicer to read that code 
and make the code fairly common.
>   }
>   
>   /* monotonic_clock(): returns # of nanoseconds passed since time_init()
> @@ -86,16 +92,24 @@ int gettimeofday(struct timeval *tv, void *tz)
>   
>   /* Set the timer and mask. */
>   void write_timer_ctl(uint32_t value) {
> +#if defined(__arm__)
>       __asm__ __volatile__(
>               "mcr p15, 0, %0, c14, c3, 1\n"
>               "isb"::"r"(value));
> +#elif defined(__aarch64__)
> +    __asm__ __volatile__("msr cntv_ctl_el0, %0" : : "r" (value));
> +#endif
>   }
>   
>   void set_vtimer_compare(uint64_t value) {
>       DEBUG("New CompareValue : %llx\n", value);
>   
> +#if defined(__arm__)
>       __asm__ __volatile__("mcrr p15, 3, %0, %H0, c14"
>               ::"r"(value));
> +#elif defined(__aarch64__)
> +    __asm__ __volatile__("msr cntv_cval_el0, %0" : : "r" (value));
> +#endif
>   
>       /* Enable timer and unmask the output signal */
>       write_timer_ctl(1);
Cheers,

--
Julien Grall

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