From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:8904 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729095AbgFHINM (ORCPT ); Mon, 8 Jun 2020 04:13:12 -0400 From: Pierre Morel Subject: [kvm-unit-tests PATCH v8 06/12] s390x: clock and delays caluculations Date: Mon, 8 Jun 2020 10:12:55 +0200 Message-Id: <1591603981-16879-7-git-send-email-pmorel@linux.ibm.com> In-Reply-To: <1591603981-16879-1-git-send-email-pmorel@linux.ibm.com> References: <1591603981-16879-1-git-send-email-pmorel@linux.ibm.com> Sender: linux-s390-owner@vger.kernel.org List-ID: To: kvm@vger.kernel.org Cc: linux-s390@vger.kernel.org, frankja@linux.ibm.com, david@redhat.com, thuth@redhat.com, cohuck@redhat.com 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 --- 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..eb15941 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 (63 - 51) +#define STCK_MAX ((1 << (STCK_SHIFT + 1)) - 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; +} + +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; } #endif -- 2.25.1