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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 F1618C4CECB for ; Thu, 12 Sep 2019 11:37:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BC0FF20684 for ; Thu, 12 Sep 2019 11:37:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731211AbfILLh4 (ORCPT ); Thu, 12 Sep 2019 07:37:56 -0400 Received: from shards.monkeyblade.net ([23.128.96.9]:56474 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730268AbfILLhz (ORCPT ); Thu, 12 Sep 2019 07:37:55 -0400 Received: from localhost (unknown [148.69.85.38]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 5C7F3142387A4; Thu, 12 Sep 2019 04:37:54 -0700 (PDT) Date: Thu, 12 Sep 2019 13:37:53 +0200 (CEST) Message-Id: <20190912.133753.1473374980190418320.davem@davemloft.net> To: olteanv@gmail.com Cc: f.fainelli@gmail.com, vivien.didelot@gmail.com, andrew@lunn.ch, richardcochran@gmail.com, netdev@vger.kernel.org Subject: Re: [PATCH v2 net-next 3/7] net: dsa: sja1105: Switch to hardware operations for PTP From: David Miller In-Reply-To: References: <20190910013501.3262-4-olteanv@gmail.com> <20190912.121203.1106283271122334199.davem@davemloft.net> X-Mailer: Mew version 6.8 on Emacs 26.2 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Thu, 12 Sep 2019 04:37:55 -0700 (PDT) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Vladimir Oltean Date: Thu, 12 Sep 2019 11:17:11 +0100 > Hi Dave, > > On 12/09/2019, David Miller wrote: >> From: Vladimir Oltean >> Date: Tue, 10 Sep 2019 04:34:57 +0300 >> >>> static int sja1105_ptp_adjfine(struct ptp_clock_info *ptp, long >>> scaled_ppm) >>> { >>> struct sja1105_private *priv = ptp_to_sja1105(ptp); >>> + const struct sja1105_regs *regs = priv->info->regs; >>> s64 clkrate; >>> + int rc; >> .. >>> -static int sja1105_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta) >>> -{ >>> - struct sja1105_private *priv = ptp_to_sja1105(ptp); >>> + rc = sja1105_spi_send_int(priv, SPI_WRITE, regs->ptpclkrate, >>> + &clkrate, 4); >> >> You're sending an arbitrary 4 bytes of a 64-bit value. This works on little >> endian >> but will not on big endian. >> >> Please properly copy this clkrate into a "u32" variable and pass that into >> sja1105_spi_send_int(). >> >> It also seems to suggest that you want to use abs() to perform that weird >> centering around 1 << 31 calculation. >> >> Thank you. >> > > It looks 'wrong' but it isn't. The driver uses the 'packing' framework > (lib/packing.c) which is endian-agnostic (converts between CPU and > peripheral endianness) and operates on u64 as the CPU word size. On > the contrary, u32 would not work with the 'packing' API in its current > form, but I don't see yet any reasons to extend it (packing64, > packing32 etc). That's extremely unintuitive and makes auditing patches next to impossible.