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 Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0F55DC54791 for ; Thu, 22 Feb 2024 16:46:05 +0000 (UTC) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=bootlin.com header.i=@bootlin.com header.a=rsa-sha256 header.s=gm1 header.b=dtJdpcTG; dkim-atps=neutral Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4TgfCw48P3z3vXH for ; Fri, 23 Feb 2024 03:46:04 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=bootlin.com header.i=@bootlin.com header.a=rsa-sha256 header.s=gm1 header.b=dtJdpcTG; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=bootlin.com (client-ip=2001:4b98:dc4:8::225; helo=relay5-d.mail.gandi.net; envelope-from=herve.codina@bootlin.com; receiver=lists.ozlabs.org) Received: from relay5-d.mail.gandi.net (relay5-d.mail.gandi.net [IPv6:2001:4b98:dc4:8::225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4TgfC3238Wz3ccV for ; Fri, 23 Feb 2024 03:45:16 +1100 (AEDT) Received: by mail.gandi.net (Postfix) with ESMTPSA id 4F0FA1C000E; Thu, 22 Feb 2024 16:45:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1708620305; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ugQVlVJpeQXBsFdN2IMSxN837NOg0+Zdb5sbx96BxmA=; b=dtJdpcTGIjeSZZpYrmyBG59jMtXBRcV5N1W+0XWKz/Zk/TuUEsQG4YgGfunYWBIIuCkQij 7m7qEXCXzlnByoVeJHPniQmq4/X10I+ydMDG1OJnnaHxo9RdSwSwavnAip0d/+9qVJACq6 hTnI7jGBLT525O3JjOTnwTZApqfq8bb8aLdR1n0obY8hK8e1VDK3qF0VHlXa63q6hIw3Aq o1jGlT4P70nIA3vIbCjePvwB8obkynKcAJpZfF81ug1oxMYZuFuwSvcoTMq0uDSfwd4d/a AF/R3qkhF/Sq90kMKXtXpFhgG3Y89lm4lIXpWEqTvZ5ON8qkrFA2e/2ps4h4lA== Date: Thu, 22 Feb 2024 17:45:01 +0100 From: Herve Codina To: Andy Shevchenko Subject: Re: [PATCH v4 1/5] net: wan: Add support for QMC HDLC Message-ID: <20240222174501.4cbe03ab@bootlin.com> In-Reply-To: References: <20240222142219.441767-1-herve.codina@bootlin.com> <20240222142219.441767-2-herve.codina@bootlin.com> Organization: Bootlin X-Mailer: Claws Mail 4.2.0 (GTK 3.24.38; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-GND-Sasl: herve.codina@bootlin.com X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Andrew Lunn , Vadim Fedorenko , Yury Norov , netdev@vger.kernel.org, Rasmus Villemoes , linux-kernel@vger.kernel.org, Eric Dumazet , Mark Brown , Thomas Petazzoni , Jakub Kicinski , Paolo Abeni , linuxppc-dev@lists.ozlabs.org, "David S. Miller" Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Thu, 22 Feb 2024 17:29:05 +0200 Andy Shevchenko wrote: > On Thu, Feb 22, 2024 at 03:22:14PM +0100, Herve Codina wrote: > > The QMC HDLC driver provides support for HDLC using the QMC (QUICC > > Multichannel Controller) to transfer the HDLC data. > > ... > > > +struct qmc_hdlc { > > + struct device *dev; > > + struct qmc_chan *qmc_chan; > > + struct net_device *netdev; > > + bool is_crc32; > > + spinlock_t tx_lock; /* Protect tx descriptors */ > > Just wondering if above tx/rx descriptors should be aligned on a cacheline > for DMA? These descriptors are not used by DMA. Not sure that aligning them to a cacheline is really needed. > > > + struct qmc_hdlc_desc tx_descs[8]; > > + unsigned int tx_out; > > + struct qmc_hdlc_desc rx_descs[4]; > > +}; > > ... > > > +#define QMC_HDLC_RX_ERROR_FLAGS (QMC_RX_FLAG_HDLC_OVF | \ > > + QMC_RX_FLAG_HDLC_UNA | \ > > + QMC_RX_FLAG_HDLC_ABORT | \ > > + QMC_RX_FLAG_HDLC_CRC) > > Wouldn't be slightly better to have it as > > #define QMC_HDLC_RX_ERROR_FLAGS \ > (QMC_RX_FLAG_HDLC_OVF | QMC_RX_FLAG_HDLC_UNA | \ > QMC_RX_FLAG_HDLC_CRC | QMC_RX_FLAG_HDLC_ABORT) > > ? Will be done in the next iteration. > > ... > > > + ret = qmc_chan_write_submit(qmc_hdlc->qmc_chan, desc->dma_addr, desc->dma_size, > > + qmc_hdlc_xmit_complete, desc); > > + if (ret) { > > > + dev_err(qmc_hdlc->dev, "qmc chan write returns %d\n", ret); > > + dma_unmap_single(qmc_hdlc->dev, desc->dma_addr, desc->dma_size, DMA_TO_DEVICE); > > + return ret; > > I would do other way around, i.e. release resource followed up by printing > a message. Printing a message is a slow operation and may prevent the (soon > freed) resources to be re-used earlier. Will do that in the next iteration. > > > + } > > ... > > > + spin_lock_irqsave(&qmc_hdlc->tx_lock, flags); > > Why not using cleanup.h from day 1? I don't know about cleanup.h. Can you tell me more ? How should I use it ? > > > +end: > > This label, in particular, will not be needed with above in place. > > > + spin_unlock_irqrestore(&qmc_hdlc->tx_lock, flags); > > + return ret; > > +} > > ... > > > + /* Queue as many recv descriptors as possible */ > > + for (i = 0; i < ARRAY_SIZE(qmc_hdlc->rx_descs); i++) { > > + desc = &qmc_hdlc->rx_descs[i]; > > + > > + desc->netdev = netdev; > > + ret = qmc_hdlc_recv_queue(qmc_hdlc, desc, chan_param.hdlc.max_rx_buf_size); > > > + if (ret) { > > + if (ret == -EBUSY && i != 0) > > + break; /* We use all the QMC chan capability */ > > + goto free_desc; > > + } > > Can be unfolded to > > if (ret == -EBUSY && i) > break; /* We use all the QMC chan capability */ > if (ret) > goto free_desc; > > Easy to read and understand. Sure, will be changed. > > > + } > > ... > > > +static int qmc_hdlc_probe(struct platform_device *pdev) > > +{ > > With > > struct device *dev = &pdev->dev; > > the below code will be neater (see other comments for the examples). Will use that. > > > + struct device_node *np = pdev->dev.of_node; > > It is used only once, drop it (see below). Ok. > > > + struct qmc_hdlc *qmc_hdlc; > > + struct qmc_chan_info info; > > + hdlc_device *hdlc; > > + int ret; > > + > > + qmc_hdlc = devm_kzalloc(&pdev->dev, sizeof(*qmc_hdlc), GFP_KERNEL); > > + if (!qmc_hdlc) > > + return -ENOMEM; > > + > > + qmc_hdlc->dev = &pdev->dev; > > + spin_lock_init(&qmc_hdlc->tx_lock); > > + > > + qmc_hdlc->qmc_chan = devm_qmc_chan_get_bychild(qmc_hdlc->dev, np); > > qmc_hdlc->qmc_chan = devm_qmc_chan_get_bychild(dev, dev->of_node); > > > + if (IS_ERR(qmc_hdlc->qmc_chan)) { > > + ret = PTR_ERR(qmc_hdlc->qmc_chan); > > + return dev_err_probe(qmc_hdlc->dev, ret, "get QMC channel failed\n"); > > return dev_err_probe(dev, PTR_ERR(qmc_hdlc->qmc_chan), "get QMC channel failed\n"); > > > + } > > + > > + ret = qmc_chan_get_info(qmc_hdlc->qmc_chan, &info); > > + if (ret) { > > > + dev_err(qmc_hdlc->dev, "get QMC channel info failed %d\n", ret); > > + return ret; > > Why not using same message pattern everywhere, i.e. dev_err_probe()? > > return dev_err_probe(dev, ret, "get QMC channel info failed\n"); > > (and so on...) No reason. Just because I missed them. Will be updated using dev_err_probe(). > > > + } > > + > > + if (info.mode != QMC_HDLC) { > > + dev_err(qmc_hdlc->dev, "QMC chan mode %d is not QMC_HDLC\n", > > + info.mode); > > + return -EINVAL; > > + } > > + > > + qmc_hdlc->netdev = alloc_hdlcdev(qmc_hdlc); > > + if (!qmc_hdlc->netdev) { > > > + dev_err(qmc_hdlc->dev, "failed to alloc hdlc dev\n"); > > + return -ENOMEM; > > We do not issue a message for -ENOMEM. And I know :( Will be updated. > > > + } > > + > > + hdlc = dev_to_hdlc(qmc_hdlc->netdev); > > + hdlc->attach = qmc_hdlc_attach; > > + hdlc->xmit = qmc_hdlc_xmit; > > + SET_NETDEV_DEV(qmc_hdlc->netdev, qmc_hdlc->dev); > > + qmc_hdlc->netdev->tx_queue_len = ARRAY_SIZE(qmc_hdlc->tx_descs); > > + qmc_hdlc->netdev->netdev_ops = &qmc_hdlc_netdev_ops; > > + ret = register_hdlc_device(qmc_hdlc->netdev); > > + if (ret) { > > + dev_err(qmc_hdlc->dev, "failed to register hdlc device (%d)\n", ret); > > + goto free_netdev; > > + } > > + > > + platform_set_drvdata(pdev, qmc_hdlc); > > + > > + return 0; > > + > > +free_netdev: > > + free_netdev(qmc_hdlc->netdev); > > + return ret; > > +} > > Thanks for the review. Hervé