From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ej1-f53.google.com (mail-ej1-f53.google.com [209.85.218.53]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 59B5172 for ; Thu, 17 Jun 2021 17:32:46 +0000 (UTC) Received: by mail-ej1-f53.google.com with SMTP id g8so11192970ejx.1 for ; Thu, 17 Jun 2021 10:32:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=3i2scYylnSG4Z6Xt/QfleyGEEfWXFHNAywICtigK1cw=; b=tniGSWpJZH+WdHXyBhV8MvePfO1Ws4QdjS9f2FgYpJrTpYlNvAJvDHJGD+gQJq7p5V FTQRB35xGmjTph+Vs4BmhjhkVGwEW2r0D1NBa14cJoWO/+a/mPXGeviuuExP+AcOjUNk 3hvMC+mUMpzvN1LK9sOR4QId5R7LOIlutiSOeOv+9yeOgWRD+57/JVlQi9e4OcBkjOhQ 2zZ8ZJPNjY5QLbqqCjpnk0Q2nBGPEQtLWkPo9LbRkbrfPjB3L3v3+Di/JpmxalYC25xI EJjZjaNxpHNeMkX/Gsaa31hEm15Jxo5ybpLxQR3GIhwZt0uYzvvqPnqSI7MdBsWxEj2Z VLAw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=3i2scYylnSG4Z6Xt/QfleyGEEfWXFHNAywICtigK1cw=; b=Dk5WVZL2Zit+4ycxxFMMLjvtf/WhXXJx3Jcyfr8sJly/tXgxG/QQRH8d+y6Sept1SA 970yk7YC/eN2S1WkGDqJqDSi82s3H6vfi/mcG1+4tSOxgM0Q7pUj2lFEcyISCPt7azvv ZZCEStfgexYwHcpzgB+fYaqE58YoD7stVvlLUe/12WNlBSUKADscb4WRHoSfMldexMtM ClqQwzPRbHjvNGqoTOT96LumCGVPy7wbJsCcPwbAbBLwThO3io+zApDShkpLfqZ4diL1 1dB3qryT2903ve7kLUv5ZGVOy5Ta4RgOoQzi9kOLhZCo3rwBa6fDq/dw+SwjSDMMf+Vm /2Ig== X-Gm-Message-State: AOAM530wsCs9Tik2xM5gh+qUJhdC4f2q3armQKgDVnPud7uNSw9Szd4c iilkFEMzl3KvTdamZARk+Ao= X-Google-Smtp-Source: ABdhPJx1+lax+LYVkXfY/djET+bMTKIUY+oPtfmMN3+W7WnRo7laNBtIDQAAmzELk38/ltYs3OXCsw== X-Received: by 2002:aa7:dd8d:: with SMTP id g13mr8394054edv.30.1623951163866; Thu, 17 Jun 2021 10:32:43 -0700 (PDT) Received: from localhost ([185.246.22.209]) by smtp.gmail.com with ESMTPSA id s4sm4779099edu.49.2021.06.17.10.32.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 17 Jun 2021 10:32:43 -0700 (PDT) Date: Thu, 17 Jun 2021 19:32:38 +0200 From: Richard Cochran To: Yangbo Lu Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, mptcp@lists.linux.dev, "David S . Miller" , Jakub Kicinski , Mat Martineau , Matthieu Baerts , Shuah Khan , Michal Kubecek , Florian Fainelli , Andrew Lunn , Rui Sousa , Sebastien Laveze Subject: Re: [net-next, v3, 01/10] ptp: add ptp virtual clock driver framework Message-ID: <20210617173237.GA4770@localhost> References: <20210615094517.48752-1-yangbo.lu@nxp.com> <20210615094517.48752-2-yangbo.lu@nxp.com> X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210615094517.48752-2-yangbo.lu@nxp.com> User-Agent: Mutt/1.10.1 (2018-07-13) On Tue, Jun 15, 2021 at 05:45:08PM +0800, Yangbo Lu wrote: > diff --git a/drivers/ptp/Makefile b/drivers/ptp/Makefile > index 8673d1743faa..3c6a905760e2 100644 > --- a/drivers/ptp/Makefile > +++ b/drivers/ptp/Makefile > @@ -3,7 +3,7 @@ > # Makefile for PTP 1588 clock support. > # > > -ptp-y := ptp_clock.o ptp_chardev.o ptp_sysfs.o > +ptp-y := ptp_clock.o ptp_vclock.o ptp_chardev.o ptp_sysfs.o Nit: Please place ptp_vclock.o at the end of the list. > ptp_kvm-$(CONFIG_X86) := ptp_kvm_x86.o ptp_kvm_common.o > ptp_kvm-$(CONFIG_HAVE_ARM_SMCCC) := ptp_kvm_arm.o ptp_kvm_common.o > obj-$(CONFIG_PTP_1588_CLOCK) += ptp.o > diff --git a/drivers/ptp/ptp_private.h b/drivers/ptp/ptp_private.h > index 6b97155148f1..3f388d63904c 100644 > --- a/drivers/ptp/ptp_private.h > +++ b/drivers/ptp/ptp_private.h > @@ -48,6 +48,20 @@ struct ptp_clock { > struct kthread_delayed_work aux_work; > }; > > +#define info_to_vclock(d) container_of((d), struct ptp_vclock, info) > +#define cc_to_vclock(d) container_of((d), struct ptp_vclock, cc) > +#define dw_to_vclock(d) container_of((d), struct ptp_vclock, refresh_work) > + > +struct ptp_vclock { > + struct ptp_clock *pclock; > + struct ptp_clock_info info; > + struct ptp_clock *clock; > + struct cyclecounter cc; > + struct timecounter tc; > + spinlock_t lock; /* protects tc/cc */ > + struct delayed_work refresh_work; Can we please have a kthread worker here instead of work? Experience shows that plain work can be delayed for a long, long time on busy systems. > +}; > + > /* > * The function queue_cnt() is safe for readers to call without > * holding q->lock. Readers use this function to verify that the queue > @@ -89,4 +103,6 @@ extern const struct attribute_group *ptp_groups[]; > int ptp_populate_pin_groups(struct ptp_clock *ptp); > void ptp_cleanup_pin_groups(struct ptp_clock *ptp); > > +struct ptp_vclock *ptp_vclock_register(struct ptp_clock *pclock); > +void ptp_vclock_unregister(struct ptp_vclock *vclock); > #endif > diff --git a/drivers/ptp/ptp_vclock.c b/drivers/ptp/ptp_vclock.c > new file mode 100644 > index 000000000000..b8f500677314 > --- /dev/null > +++ b/drivers/ptp/ptp_vclock.c > @@ -0,0 +1,154 @@ > +// SPDX-License-Identifier: GPL-2.0-or-later > +/* > + * PTP virtual clock driver > + * > + * Copyright 2021 NXP > + */ > +#include > +#include "ptp_private.h" > + > +#define PTP_VCLOCK_CC_MULT (1 << 31) > +#define PTP_VCLOCK_CC_SHIFT 31 These two are okay, but ... > +#define PTP_VCLOCK_CC_MULT_NUM (1 << 9) > +#define PTP_VCLOCK_CC_MULT_DEM 15625ULL the similarity of naming is confusing for these two. They are only used in the .adjfine method. How about this? PTP_VCLOCK_FADJ_NUMERATOR, or even PTP_VCLOCK_FADJ_SHIFT (see below) PTP_VCLOCK_FADJ_DENOMINATOR > +#define PTP_VCLOCK_CC_REFRESH_INTERVAL (HZ * 2) Consider dropping CC from the name. PTP_VCLOCK_REFRESH_INTERVAL sounds good to me. > +static int ptp_vclock_adjfine(struct ptp_clock_info *ptp, long scaled_ppm) > +{ > + struct ptp_vclock *vclock = info_to_vclock(ptp); > + unsigned long flags; > + s64 adj; > + > + adj = (s64)scaled_ppm * PTP_VCLOCK_CC_MULT_NUM; Rather than scaled_ppm * (1 << 9) I suggest scaled_ppm << 9 instead. I suppose a good compiler would replace the multiplication with a bit shift, but it never hurts to spell it out. > + adj = div_s64(adj, PTP_VCLOCK_CC_MULT_DEM); > + > + spin_lock_irqsave(&vclock->lock, flags); > + timecounter_read(&vclock->tc); > + vclock->cc.mult = PTP_VCLOCK_CC_MULT + adj; > + spin_unlock_irqrestore(&vclock->lock, flags); > + > + return 0; > +} Thanks, Richard