From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A356DC433E0 for ; Wed, 17 Jun 2020 11:05:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8742720CC7 for ; Wed, 17 Jun 2020 11:05:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726702AbgFQLFA (ORCPT ); Wed, 17 Jun 2020 07:05:00 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:44886 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725554AbgFQLE7 (ORCPT ); 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Wed, 17 Jun 2020 11:04:55 +0000 Received: from d06av25.portsmouth.uk.ibm.com (d06av25.portsmouth.uk.ibm.com [9.149.105.61]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 05HB4rwW63045856 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 17 Jun 2020 11:04:53 GMT Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id BDD0011C064; Wed, 17 Jun 2020 11:04:53 +0000 (GMT) Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 59DF011C05C; Wed, 17 Jun 2020 11:04:53 +0000 (GMT) Received: from oc3016276355.ibm.com (unknown [9.145.186.32]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 17 Jun 2020 11:04:53 +0000 (GMT) Subject: Re: [kvm-unit-tests PATCH v9 06/12] s390x: clock and delays caluculations To: Cornelia Huck Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org, frankja@linux.ibm.com, david@redhat.com, thuth@redhat.com References: <1592213521-19390-1-git-send-email-pmorel@linux.ibm.com> <1592213521-19390-7-git-send-email-pmorel@linux.ibm.com> <20200617102704.7755e11a.cohuck@redhat.com> From: Pierre Morel Message-ID: <89cdae3e-1f50-03c1-e8ef-1f6b87a22fa9@linux.ibm.com> Date: Wed, 17 Jun 2020 13:04:52 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: <20200617102704.7755e11a.cohuck@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.216,18.0.687 definitions=2020-06-17_03:2020-06-17,2020-06-17 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 malwarescore=0 phishscore=0 clxscore=1015 cotscore=-2147483648 suspectscore=0 spamscore=0 mlxscore=0 priorityscore=1501 bulkscore=0 mlxlogscore=999 adultscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2006170087 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 2020-06-17 10:27, Cornelia Huck wrote: > On Mon, 15 Jun 2020 11:31:55 +0200 > 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 >> --- >> 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 */ > > That comment may now be a tad non-obvious, because the details are > hidden behind the #define? Anyway, no strong opinion. You are right. I find the macro's name is explicit so I remove the comment. > >> - 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; >> } >> >> #endif > > Acked-by: Cornelia Huck > Thanks, Pierre -- Pierre Morel IBM Lab Boeblingen