Merged,
Maxim.
On 06/08/17 07:04, Bill Fischofer wrote:
> On Wed, Jun 7, 2017 at 10:46 PM, Brian Brooks <[email protected]> wrote:
>> Expose ARMv8 Generic Timer through internal CPU global time functions.
>>
>> Signed-off-by: Brian Brooks <[email protected]>
>
> Reviewed-by: Bill Fischofer <[email protected]>
>
>>
>> ---
>>
>> v2:
>> - Add text to explain the usage of the ARM architected timer (Petri)
>>
>>
>> platform/linux-generic/arch/arm/odp_cpu_arch.c | 38
>> +++++++++++++++++++++++++-
>> 1 file changed, 37 insertions(+), 1 deletion(-)
>>
>> diff --git a/platform/linux-generic/arch/arm/odp_cpu_arch.c
>> b/platform/linux-generic/arch/arm/odp_cpu_arch.c
>> index c31f9084..91d439d9 100644
>> --- a/platform/linux-generic/arch/arm/odp_cpu_arch.c
>> +++ b/platform/linux-generic/arch/arm/odp_cpu_arch.c
>> @@ -50,15 +50,51 @@ uint64_t odp_cpu_cycles_resolution(void)
>>
>> int cpu_has_global_time(void)
>> {
>> - return 0;
>> + uint64_t hz = cpu_global_time_freq();
>> +
>> + /*
>> + * The system counter portion of the architected timer must
>> + * provide a uniform view of system time to all processing
>> + * elements in the system. This should hold true even for
>> + * heterogeneous SoCs.
>> + *
>> + * Determine whether the system has 'global time' by checking
>> + * whether a read of the architected timer frequency sys reg
>> + * returns a sane value. Sane is considered to be within
>> + * 1MHz and 6GHz (1us and .1667ns period).
>> + */
>> + return hz >= 1000000 && hz <= 6000000000;
>> }
>>
>> uint64_t cpu_global_time(void)
>> {
>> +#if __ARM_ARCH == 8
>> + uint64_t cntvct;
>> +
>> + /*
>> + * To be consistent with other architectures, do not issue a
>> + * serializing instruction, e.g. ISB, before reading this
>> + * sys reg.
>> + */
>> +
>> + /* Memory clobber to minimize optimization around load from sys reg.
>> */
>> + __asm__ volatile("mrs %0, cntvct_el0" : "=r"(cntvct) : : "memory");
>> +
>> + return cntvct;
>> +#else
>> return 0;
>> +#endif
>> }
>>
>> uint64_t cpu_global_time_freq(void)
>> {
>> +#if __ARM_ARCH == 8
>> + uint64_t cntfrq;
>> +
>> + __asm__ volatile("mrs %0, cntfrq_el0" : "=r"(cntfrq) : : );
>> +
>> + return cntfrq;
>> +#else
>> return 0;
>> +#endif
>> }
>> --
>> 2.13.0
>>
