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=-6.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,T_DKIMWL_WL_HIGH,USER_AGENT_GIT autolearn=unavailable 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 5FA92C468BD for ; Sun, 9 Jun 2019 17:18:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 348CC20652 for ; Sun, 9 Jun 2019 17:18:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560100702; bh=uB5oQ6bH3HcUn2NASKWxGUvIkIh26igzAHWj7XzqOvY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=QOrcNimdAw1aR1uP/BU+ZTU2dSI/TxdJxs8mB+Uk/rWSGtyDDQ+OxaJjWt5v/IMA5 y/L6H3In3obgCSY/6sFsA0ZXug5QlzwfhAeK7DLYSALianYo8KranyGYU4U5w4bmMx EGN75uPahTRNV6XnfEQlOW4e4zTvMjaqeFCm/JMk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729765AbfFIQu0 (ORCPT ); Sun, 9 Jun 2019 12:50:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:50280 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731715AbfFIQuZ (ORCPT ); Sun, 9 Jun 2019 12:50:25 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 230A7207E0; Sun, 9 Jun 2019 16:50:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560099024; bh=uB5oQ6bH3HcUn2NASKWxGUvIkIh26igzAHWj7XzqOvY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rkb/WEraPyN1u0k1jUcPrs8ZcsusQ+XsaALgVHwd5Q8hjIsuVESBOevt3vOiSqPTF XPT90uDaHRLLFZo8QAgBB1RNzS3xtTcmkhanVGD6Myt5neSVJ7qVttrpW+V75yMipf r2TtnqFREn+aqjOMOH0idI/q5g4Ejqd2PS3SWKKU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Russell King , Andrew Lunn , "David S. Miller" Subject: [PATCH 4.14 09/35] net: sfp: read eeprom in maximum 16 byte increments Date: Sun, 9 Jun 2019 18:42:15 +0200 Message-Id: <20190609164126.046628834@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190609164125.377368385@linuxfoundation.org> References: <20190609164125.377368385@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Russell King [ Upstream commit 28e74a7cfd6403f0d1c0f8b10b45d6fae37b227e ] Some SFP modules do not like reads longer than 16 bytes, so read the EEPROM in chunks of 16 bytes at a time. This behaviour is not specified in the SFP MSAs, which specifies: "The serial interface uses the 2-wire serial CMOS E2PROM protocol defined for the ATMEL AT24C01A/02/04 family of components." and "As long as the SFP+ receives an acknowledge, it shall serially clock out sequential data words. The sequence is terminated when the host responds with a NACK and a STOP instead of an acknowledge." We must avoid breaking a read across a 16-bit quantity in the diagnostic page, thankfully all 16-bit quantities in that page are naturally aligned. Signed-off-by: Russell King Reviewed-by: Andrew Lunn Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/phy/sfp.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) --- a/drivers/net/phy/sfp.c +++ b/drivers/net/phy/sfp.c @@ -168,6 +168,7 @@ static int sfp__i2c_read(struct i2c_adap void *buf, size_t len) { struct i2c_msg msgs[2]; + size_t this_len; int ret; msgs[0].addr = bus_addr; @@ -179,11 +180,26 @@ static int sfp__i2c_read(struct i2c_adap msgs[1].len = len; msgs[1].buf = buf; - ret = i2c_transfer(i2c, msgs, ARRAY_SIZE(msgs)); - if (ret < 0) - return ret; + while (len) { + this_len = len; + if (this_len > 16) + this_len = 16; - return ret == ARRAY_SIZE(msgs) ? len : 0; + msgs[1].len = this_len; + + ret = i2c_transfer(i2c, msgs, ARRAY_SIZE(msgs)); + if (ret < 0) + return ret; + + if (ret != ARRAY_SIZE(msgs)) + break; + + msgs[1].buf += this_len; + dev_addr += this_len; + len -= this_len; + } + + return msgs[1].buf - (u8 *)buf; } static int sfp_i2c_read(struct sfp *sfp, bool a2, u8 addr, void *buf,