From: Janosch Frank <frankja@linux.ibm.com>
To: Pierre Morel <pmorel@linux.ibm.com>, kvm@vger.kernel.org
Cc: linux-s390@vger.kernel.org, david@redhat.com, thuth@redhat.com,
cohuck@redhat.com
Subject: Re: [kvm-unit-tests PATCH v9 06/12] s390x: clock and delays caluculations
Date: Mon, 22 Jun 2020 11:09:29 +0200 [thread overview]
Message-ID: <7659047a-a0f9-b959-c286-b150477d15ab@linux.ibm.com> (raw)
In-Reply-To: <1592213521-19390-7-git-send-email-pmorel@linux.ibm.com>
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On 6/15/20 11:31 AM, Pierre Morel wrote:
> The hardware gives us a good definition of the microsecond,
> let's keep this information and let the routine accessing
> the hardware keep all the information and return microseconds.
>
> Calculate delays in microseconds and take care about wrapping
> around zero.
>
> Define values with macros and use inlines to keep the
> milliseconds interface.
>
> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Small nit below.
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
> ---
> lib/s390x/asm/time.h | 29 +++++++++++++++++++++++++++--
> 1 file changed, 27 insertions(+), 2 deletions(-)
>
> diff --git a/lib/s390x/asm/time.h b/lib/s390x/asm/time.h
> index 1791380..7f1d891 100644
> --- a/lib/s390x/asm/time.h
> +++ b/lib/s390x/asm/time.h
> @@ -13,14 +13,39 @@
> #ifndef ASM_S390X_TIME_H
> #define ASM_S390X_TIME_H
>
> -static inline uint64_t get_clock_ms(void)
> +#define STCK_SHIFT_US (63 - 51)
> +#define STCK_MAX ((1UL << 52) - 1)
> +
> +static inline uint64_t get_clock_us(void)
> {
> uint64_t clk;
>
> asm volatile(" stck %0 " : : "Q"(clk) : "memory");
>
> /* Bit 51 is incrememented each microsecond */
> - return (clk >> (63 - 51)) / 1000;
> + return clk >> STCK_SHIFT_US;
> +}
> +
> +static inline void udelay(unsigned long us)
> +{
> + unsigned long startclk = get_clock_us();
> + unsigned long c;
> +
> + do {
> + c = get_clock_us();
> + if (c < startclk)
> + c += STCK_MAX;
> + } while (c < startclk + us);
> +}
> +
> +static inline void mdelay(unsigned long ms)
> +{
> + udelay(ms * 1000);
> +}
> +
> +static inline uint64_t get_clock_ms(void)
> +{
> + return get_clock_us() / 1000;
> }
Why don't you put that below to the get_clock_us()?
>
> #endif
>
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next prev parent reply other threads:[~2020-06-22 9:09 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-15 9:31 [kvm-unit-tests PATCH v9 00/12] s390x: Testing the Channel Subsystem I/O Pierre Morel
2020-06-15 9:31 ` [kvm-unit-tests PATCH v9 01/12] s390x: Use PSW bits definitions in cstart Pierre Morel
2020-06-16 9:31 ` Thomas Huth
2020-06-16 9:39 ` Pierre Morel
2020-06-16 13:13 ` Thomas Huth
2020-06-16 13:58 ` Pierre Morel
2020-06-16 14:01 ` Pierre Morel
2020-06-16 15:14 ` Thomas Huth
2020-06-16 16:08 ` Pierre Morel
2020-06-16 16:11 ` Pierre Morel
2020-06-15 9:31 ` [kvm-unit-tests PATCH v9 02/12] s390x: Move control register bit definitions and add AFP to them Pierre Morel
2020-06-15 9:31 ` [kvm-unit-tests PATCH v9 03/12] s390x: saving regs for interrupts Pierre Morel
2020-06-17 8:13 ` Cornelia Huck
2020-06-15 9:31 ` [kvm-unit-tests PATCH v9 04/12] s390x: interrupt registration Pierre Morel
2020-06-17 8:20 ` Cornelia Huck
2020-06-17 11:01 ` Pierre Morel
2020-06-15 9:31 ` [kvm-unit-tests PATCH v9 05/12] s390x: export the clock get_clock_ms() utility Pierre Morel
2020-06-15 9:31 ` [kvm-unit-tests PATCH v9 06/12] s390x: clock and delays caluculations Pierre Morel
2020-06-16 9:35 ` Thomas Huth
2020-06-16 9:40 ` Pierre Morel
2020-06-17 8:27 ` Cornelia Huck
2020-06-17 11:04 ` Pierre Morel
2020-06-22 9:09 ` Janosch Frank [this message]
2020-06-30 16:13 ` Pierre Morel
2020-06-15 9:31 ` [kvm-unit-tests PATCH v9 07/12] s390x: define function to wait for interrupt Pierre Morel
2020-06-15 9:31 ` [kvm-unit-tests PATCH v9 08/12] s390x: retrieve decimal and hexadecimal kernel parameters Pierre Morel
2020-06-16 9:47 ` Thomas Huth
2020-06-16 13:43 ` Pierre Morel
2020-06-17 8:37 ` Cornelia Huck
2020-06-17 11:05 ` Pierre Morel
2020-06-22 9:33 ` Janosch Frank
2020-06-22 10:57 ` Andrew Jones
2020-07-02 12:53 ` Pierre Morel
2020-06-15 9:31 ` [kvm-unit-tests PATCH v9 09/12] s390x: Library resources for CSS tests Pierre Morel
2020-06-16 10:31 ` Thomas Huth
2020-06-16 13:42 ` Pierre Morel
2020-06-17 8:42 ` Cornelia Huck
2020-06-17 11:08 ` Pierre Morel
2020-06-22 9:35 ` Janosch Frank
2020-06-24 12:26 ` Thomas Huth
2020-06-30 16:30 ` Pierre Morel
2020-06-15 9:31 ` [kvm-unit-tests PATCH v9 10/12] s390x: css: stsch, enumeration test Pierre Morel
2020-06-16 11:37 ` Thomas Huth
2020-06-16 13:42 ` Pierre Morel
2020-06-17 8:48 ` Cornelia Huck
2020-06-17 11:14 ` Pierre Morel
2020-06-15 9:32 ` [kvm-unit-tests PATCH v9 11/12] s390x: css: msch, enable test Pierre Morel
2020-06-16 11:43 ` Thomas Huth
2020-06-16 13:43 ` Pierre Morel
2020-06-17 8:54 ` Cornelia Huck
2020-06-17 11:25 ` Pierre Morel
2020-06-15 9:32 ` [kvm-unit-tests PATCH v9 12/12] s390x: css: ssch/tsch with sense and interrupt Pierre Morel
2020-06-17 9:54 ` Cornelia Huck
2020-06-17 11:55 ` Pierre Morel
2020-06-19 6:57 ` Cornelia Huck
2020-07-02 12:56 ` Pierre Morel
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