From owner-freebsd-hackers@freebsd.org Sat Oct 19 11:45:29 2019 Return-Path: Delivered-To: freebsd-hackers@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 69FFB161AC0 for ; Sat, 19 Oct 2019 11:45:29 +0000 (UTC) (envelope-from freebsd-hackers@dino.sk) Received: from mailhost.netlabit.sk (mailhost.netlabit.sk [84.245.65.72]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 46wLgX2fXHz48F9 for ; Sat, 19 Oct 2019 11:45:27 +0000 (UTC) (envelope-from freebsd-hackers@dino.sk) Received: from zeta.dino.sk (fw3.dino.sk [84.245.95.254]) (AUTH: LOGIN milan) by mailhost.netlabit.sk with ESMTPA; Sat, 19 Oct 2019 13:45:24 +0200 id 00F407D4.5DAAF754.0000D580 Date: Sat, 19 Oct 2019 13:45:24 +0200 From: Milan Obuch To: freebsd-hackers@freebsd.org Subject: sysctl questions Message-ID: <20191019134524.3cc3d274@zeta.dino.sk> X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; i386-portbld-freebsd11.3) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 46wLgX2fXHz48F9 X-Spamd-Bar: ----- Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=pass (mx1.freebsd.org: domain of freebsd-hackers@dino.sk designates 84.245.65.72 as permitted sender) smtp.mailfrom=freebsd-hackers@dino.sk X-Spamd-Result: default: False [-5.29 / 15.00]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.000,0]; FROM_HAS_DN(0.00)[]; R_SPF_ALLOW(-0.20)[+mx]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_GOOD(-0.10)[text/plain]; TO_DN_NONE(0.00)[]; DMARC_NA(0.00)[dino.sk]; RCPT_COUNT_ONE(0.00)[1]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; RCVD_TLS_LAST(0.00)[]; RCVD_IN_DNSWL_NONE(0.00)[72.65.245.84.list.dnswl.org : 127.0.10.0]; IP_SCORE(-2.99)[ip: (-8.36), ipnet: 84.245.64.0/18(-4.18), asn: 16160(-2.47), country: SK(0.08)]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:16160, ipnet:84.245.64.0/18, country:SK]; RCVD_COUNT_TWO(0.00)[2] X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 19 Oct 2019 11:45:29 -0000 Hi, I am working on AXI XADC driver on Zynq based Zybo Z7 board. I created simple PL design to be able to use this core IP. Looking in some other ADC driver I desided to use sysctl API to report measurements. So I did create mib entry in attach function like this snprintf(pinbuf, sizeof(inum), "%d", i); inpN_node = SYSCTL_ADD_NODE(ctx, inp_tree, OID_AUTO, inum, CTLFLAG_RD, NULL, "ADC input"); inpN_tree = SYSCTL_CHILDREN(inpN_node); SYSCTL_ADD_PROC(ctx, inpN_tree, OID_AUTO, "read", CTLFLAG_RD | CTLTYPE_UINT, &axi_xadc_inputs[i], 0, axi_xadc_read_proc, "IU", "Read ADC input"); where inum is string, i is integer - input number. Top node for my mib entries is dev.adc.0.ain. When the above snippet is run for i from 0 up to Ninputs - 1, sysctl shows them in opposite order, i. e. # sysctl dev.adc.0.ain dev.adc.0.ain.3.read: dev.adc.0.ain.2.read: dev.adc.0.ain.1.read: dev.adc.0.ain.0.read: Why it is so? It looks for me a bit counter intuitive, I like the nodes be ordered the way I decide, not the other way so... so I am just calling the initialisation snippet for i starting with Ninput - 1 down to 0 and it works the way I want. Other thing I do not understand is my axi_xadc_read_proc is called *twice* per node. My procedure is short: static int axi_xadc_read_proc(SYSCTL_HANDLER_ARGS) { int error; int32_t status, value; long cvalue; struct axi_xadc_softc *sc; struct axi_xadc_input *input; input = (struct axi_xadc_input *)arg1; sc = input->sc; XADC_LOCK(sc); status = RD4(sc, AXI_XADC_SR); value = RD4(sc, input->reg); cvalue = some_conversion(value); device_printf(sc->dev, "status %.4X raw %.4X conv %ld\n", status, value, cvalue); XADC_UNLOCK(sc); error = sysctl_handle_int(oidp, &value, sizeof(value), req); if (error != 0 || req->newptr == NULL) return (error); return (0); } Doing 'sysctl dev.adc.0.ain.0.read' prints one line in my login session, but two lines on console, example is adc0: status 00F7 raw A1B6 in 45 adc0: status 00F7 raw A1D6 in 45 Naturally, these are just debug outputs, but still it makes me a bit surprised. Also, do we have somewhere documented sysctl api usage? I did not find much, just three or so man pages, all somewhat short... Regards, Milan