From nobody Wed May 08 05:35:15 2024 X-Original-To: freebsd-hackers@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4VZ3l31yVjz5KKwZ for ; Wed, 08 May 2024 05:35:27 +0000 (UTC) (envelope-from phk@critter.freebsd.dk) Received: from phk.freebsd.dk (phk.freebsd.dk [130.225.244.222]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4VZ3l26p9wz4b8b for ; Wed, 8 May 2024 05:35:26 +0000 (UTC) (envelope-from phk@critter.freebsd.dk) Authentication-Results: mx1.freebsd.org; none Received: from critter.freebsd.dk (unknown [192.168.55.3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by phk.freebsd.dk (Postfix) with ESMTPS id 68EFF89287; Wed, 08 May 2024 05:35:17 +0000 (UTC) Received: from critter.freebsd.dk (localhost [127.0.0.1]) by critter.freebsd.dk (8.18.1/8.16.1) with ESMTPS id 4485ZGsT066674 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Wed, 8 May 2024 05:35:17 GMT (envelope-from phk@critter.freebsd.dk) Received: (from phk@localhost) by critter.freebsd.dk (8.18.1/8.16.1/Submit) id 4485ZFN9066673; Wed, 8 May 2024 05:35:15 GMT (envelope-from phk) Message-Id: <202405080535.4485ZFN9066673@critter.freebsd.dk> To: John Hay cc: freebsd-hackers@freebsd.org Subject: Re: FreeBSD driver for the OCP TAP Time Card In-reply-to: From: "Poul-Henning Kamp" References: List-Id: Technical discussions relating to FreeBSD List-Archive: https://lists.freebsd.org/archives/freebsd-hackers List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-hackers@FreeBSD.org MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <66671.1715146515.1@critter.freebsd.dk> Date: Wed, 08 May 2024 05:35:15 +0000 X-Spamd-Bar: ---- X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[]; ASN(0.00)[asn:1835, ipnet:130.225.0.0/16, country:EU] X-Rspamd-Queue-Id: 4VZ3l26p9wz4b8b -------- John Hay writes: > I have been working on a FreeBSD driver for the Open Compute Project (OCP) > Time Appliance Project (TAP) Time Card. The card consists of three main > parts, a clock module, a GNSS module and a FPGA module. The firmware for > the FPGA implements a counter that is synchronized to TAI using the GNSS > module and the clock module. The counter is implemented as two 32-bit > registers, seconds and nanoseconds, like struct timespec, and make that > available on the pci-e bus. That is /precisely/ the kind of hardware timecounters were designed for :-) -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.