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Re: [PATCH v2 2/9] pc-bios: s390x: Consolidate timing functions into tim


From: Janosch Frank
Subject: Re: [PATCH v2 2/9] pc-bios: s390x: Consolidate timing functions into time.h
Date: Mon, 18 May 2020 14:09:57 +0200
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2

On 5/18/20 2:01 PM, David Hildenbrand wrote:
> [...]
> 
>>  
>> -static inline void yield(void)
>> -{
>> -    asm volatile ("diag 0,0,0x44"
>> -                  : :
>> -                  : "memory", "cc");
>> -}
>> -
> 
> Nit: Looks weird that yield() is moved to time.h
> 
> Wonder if there is a better fit for this functi
helper.h or maybe into the libc?

> 
>>  #define MAX_SECTOR_SIZE 4096
>>  
>> -static inline void sleep(unsigned int seconds)
>> -{
>> -    ulong target = get_second() + seconds;
>> -
>> -    while (get_second() < target) {
>> -        yield();
>> -    }
>> -}
>> -
>>  static inline void IPL_assert(bool term, const char *message)
>>  {
>>      if (!term) {
>> diff --git a/pc-bios/s390-ccw/time.h b/pc-bios/s390-ccw/time.h
>> new file mode 100644
>> index 0000000000..899de83ae7
>> --- /dev/null
>> +++ b/pc-bios/s390-ccw/time.h
>> @@ -0,0 +1,39 @@
>> +#ifndef TIME_H
>> +#define TIME_H
>> +
>> +static inline u64 get_clock(void)
>> +{
>> +    u64 r;
>> +
>> +    asm volatile("stck %0" : "=Q" (r) : : "cc");
>> +    return r;
>> +}
>> +
>> +static inline u64 get_time_ms(void)
>> +{
>> +    /* Bit 51 is incremented each microsecond */
>> +    return (get_clock() >> 12) / 1000;
>> +}
>> +
>> +static inline u64 get_time_seconds(void)
>> +{
>> +    return (get_time_ms()) / 1000;
> 
> return get_time_ms() / 1000;

Sure


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