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=-7.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 9CC60C47093 for ; Wed, 2 Jun 2021 11:17:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 804C2613B1 for ; Wed, 2 Jun 2021 11:17:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231597AbhFBLS5 (ORCPT ); Wed, 2 Jun 2021 07:18:57 -0400 Received: from phobos.denx.de ([85.214.62.61]:51344 "EHLO phobos.denx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229963AbhFBLSz (ORCPT ); Wed, 2 Jun 2021 07:18:55 -0400 Received: from [IPv6:::1] (p578adb1c.dip0.t-ipconnect.de [87.138.219.28]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: marex@denx.de) by phobos.denx.de (Postfix) with ESMTPSA id C031A81E53; Wed, 2 Jun 2021 13:17:10 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=denx.de; s=phobos-20191101; t=1622632631; bh=FbYl3x0iYrkU3O1k6gmPtvghVGh3IcnhZHoAhRCxpQ4=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=eXgz6pNwFZyRpn+Mhr0bhydxXnQMt1vYI9mZCzHLh91dcvpHEF7nvr8NgcCyPZpqP ywHtUZxG3qVKFHs5XyYUXJoxERHpd9EfQsT6Ute66bIgHmdx+MnyWna0dAXSO06Oxx OrrbOFmUG0mIa1OWs3A8pNuioCEqV8xmAiZ2wnWhYo9xfQjB8raNzrFo1KO6UQ+WEM 0vJoFB1q2i46CYox75uQBEG5Xggt690tfUszpp3e9D0EfEgWoorpVQ2kPtcoKHSZ8/ sB0JO56EuWmpqOwYKrnPGyN77j9b3ulhMA7fzkI7dNo4FVLAVJ6ktsL9p6SF4cyVLo oWzjN5rIDPpGg== Subject: Re: [PATCH 02/10] i2c: xiic: Add standard mode support for > 255 byte read transfers To: Raviteja Narayanam , linux-i2c@vger.kernel.org, michal.simek@xilinx.com Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, git@xilinx.com References: <20210531131948.19477-1-raviteja.narayanam@xilinx.com> <20210531131948.19477-3-raviteja.narayanam@xilinx.com> From: Marek Vasut Message-ID: <0f167c21-6bc7-0806-a536-55658a199a5b@denx.de> Date: Wed, 2 Jun 2021 13:17:10 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.0 MIME-Version: 1.0 In-Reply-To: <20210531131948.19477-3-raviteja.narayanam@xilinx.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Virus-Scanned: clamav-milter 0.102.4 at phobos.denx.de X-Virus-Status: Clean Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/31/21 3:19 PM, Raviteja Narayanam wrote: [...] > + if (i2c->dynamic) { > + u8 bytes; > + u16 val; > + > + /* Clear and enable Rx full interrupt. */ > + xiic_irq_clr_en(i2c, XIIC_INTR_RX_FULL_MASK | > + XIIC_INTR_TX_ERROR_MASK); > + > + /* > + * We want to get all but last byte, because the TX_ERROR IRQ > + * is used to indicate error ACK on the address, and > + * negative ack on the last received byte, so to not mix > + * them receive all but last. > + * In the case where there is only one byte to receive > + * we can check if ERROR and RX full is set at the same time > + */ > + rx_watermark = msg->len; > + bytes = min_t(u8, rx_watermark, IIC_RX_FIFO_DEPTH); > + bytes--; > + > + xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET, bytes); > + > + local_irq_save(flags); > + if (!(msg->flags & I2C_M_NOSTART)) > + /* write the address */ > + xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, > + i2c_8bit_addr_from_msg(msg) | > + XIIC_TX_DYN_START_MASK); > + > + xiic_irq_clr_en(i2c, XIIC_INTR_BNB_MASK); > + > + /* If last message, include dynamic stop bit with length */ > + val = (i2c->nmsgs == 1) ? XIIC_TX_DYN_STOP_MASK : 0; > + val |= msg->len; > + > + xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, val); > + local_irq_restore(flags); Is local_irq_save()/local_irq_restore() used here to prevent concurrent access to the XIIC ? [...]