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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 CD32BC49ED7 for ; Tue, 10 Sep 2019 19:01:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 99901208E4 for ; Tue, 10 Sep 2019 19:01:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="MtpWksnl" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726192AbfIJTBG (ORCPT ); Tue, 10 Sep 2019 15:01:06 -0400 Received: from mail-pl1-f194.google.com ([209.85.214.194]:40487 "EHLO mail-pl1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726043AbfIJTBF (ORCPT ); Tue, 10 Sep 2019 15:01:05 -0400 Received: by mail-pl1-f194.google.com with SMTP id y10so9007539pll.7; Tue, 10 Sep 2019 12:01:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:openpgp:autocrypt:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=7H5tszDGC6FfQhd69mW6cc7M8L7GsdmMMVOWQYCICHw=; b=MtpWksnl4dcn1LAwRq+jQmfg4Dr3Se/ahaYHvIvwlmRP9Bvku/A5kwvO2Xs9IGwqrP VZaw0qMXPbQpER/olFjxrzjLVtXHhGELHaop2PopibC92Rv6Dww9Q764zA+qwBRT1vbz 25Oe2GFFC9rbMIvRUZMaUAndWu8lrz5HbUPKasA4qWhE7lYqHCKP2qXehh2dgUFgZoQ9 8oLvnD8kNFDSeRUH/mEWxRQvzYJNnhjxMXGTIS3ipvZKWKTleR9lBvYDmMUoxakWQxI1 ZTzYVOY/Uklzp0bxtl5qYPtYdOogWChLjcgsakPuPWqvM5OqJI9Ad5MRKfp9pOIHJhvq axhg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:openpgp:autocrypt :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=7H5tszDGC6FfQhd69mW6cc7M8L7GsdmMMVOWQYCICHw=; b=aHGZ20hSkM/1L/ib0x+NJh8wbuNx94rAN8ozhR3o6s9JVhAoh2bNvInVRZk/T/nQXI NrMkU+mmgRdv5PYctugm4QwwPJcnpRXZSbxA402m8PbpV9ewOAYUCtuDZLEDJtdHHltn D1JSvZpnpohuBV8UhqYOyFxW8baetV4zfpX8Zyy2Gr9qQTq6lZiQqMqXvBkfyw55M/Nb 3ystVsMLOwn9jvSnuPG4n+H1rRlN1UDnhgdkgI+RNjfb0+i3Yiis48dLth6Wo5Oq1Kv8 CLVWKXR6uMR5rWkUqE9+SJ37Akcc+f09L3DXZXauwY/SzHLXKFrt/ihNdCrmJ9g2Vc9I e+zg== X-Gm-Message-State: APjAAAX6gQv48gn+S9T2diWQ0/JlmHxAx+K97QDb89t72PO28CRu8o8z aGdePEl5zAPkUjOtDUcBc2vp7kK0M6o= X-Google-Smtp-Source: APXvYqw+yoUzul/mIjF7vaCzUNhNWkvGJ3fFPavWyyqo3J5Tpa91ECu3J0qpDhdf3Cocgwz6r4eMcA== X-Received: by 2002:a17:902:581:: with SMTP id f1mr32450596plf.246.1568142064332; Tue, 10 Sep 2019 12:01:04 -0700 (PDT) Received: from [10.67.49.31] ([192.19.223.252]) by smtp.googlemail.com with ESMTPSA id k95sm404010pje.10.2019.09.10.12.01.02 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 10 Sep 2019 12:01:03 -0700 (PDT) Subject: Re: [PATCH net-next v2 2/2] net: stmmac: Support enhanced addressing mode for DWMAC 4.10 To: Jose Abreu , Thierry Reding Cc: "David S . Miller" , Giuseppe Cavallaro , Alexandre Torgue , Jon Hunter , Bitan Biswas , "netdev@vger.kernel.org" , "linux-tegra@vger.kernel.org" References: <20190909152546.383-1-thierry.reding@gmail.com> <20190909152546.383-2-thierry.reding@gmail.com> <20190909191329.GB23804@mithrandir> From: Florian Fainelli Openpgp: preference=signencrypt Autocrypt: addr=f.fainelli@gmail.com; prefer-encrypt=mutual; keydata= mQGiBEjPuBIRBACW9MxSJU9fvEOCTnRNqG/13rAGsj+vJqontvoDSNxRgmafP8d3nesnqPyR xGlkaOSDuu09rxuW+69Y2f1TzjFuGpBk4ysWOR85O2Nx8AJ6fYGCoeTbovrNlGT1M9obSFGQ X3IzRnWoqlfudjTO5TKoqkbOgpYqIo5n1QbEjCCwCwCg3DOH/4ug2AUUlcIT9/l3pGvoRJ0E AICDzi3l7pmC5IWn2n1mvP5247urtHFs/uusE827DDj3K8Upn2vYiOFMBhGsxAk6YKV6IP0d ZdWX6fqkJJlu9cSDvWtO1hXeHIfQIE/xcqvlRH783KrihLcsmnBqOiS6rJDO2x1eAgC8meAX SAgsrBhcgGl2Rl5gh/jkeA5ykwbxA/9u1eEuL70Qzt5APJmqVXR+kWvrqdBVPoUNy/tQ8mYc nzJJ63ng3tHhnwHXZOu8hL4nqwlYHRa9eeglXYhBqja4ZvIvCEqSmEukfivk+DlIgVoOAJbh qIWgvr3SIEuR6ayY3f5j0f2ejUMYlYYnKdiHXFlF9uXm1ELrb0YX4GMHz7QnRmxvcmlhbiBG YWluZWxsaSA8Zi5mYWluZWxsaUBnbWFpbC5jb20+iGYEExECACYCGyMGCwkIBwMCBBUCCAME FgIDAQIeAQIXgAUCVF/S8QUJHlwd3wAKCRBhV5kVtWN2DvCVAJ4u4/bPF4P3jxb4qEY8I2gS 6hG0gACffNWlqJ2T4wSSn+3o7CCZNd7SLSC5BA0ESM+4EhAQAL/o09boR9D3Vk1Tt7+gpYr3 WQ6hgYVON905q2ndEoA2J0dQxJNRw3snabHDDzQBAcqOvdi7YidfBVdKi0wxHhSuRBfuOppu pdXkb7zxuPQuSveCLqqZWRQ+Cc2QgF7SBqgznbe6Ngout5qXY5Dcagk9LqFNGhJQzUGHAsIs hap1f0B1PoUyUNeEInV98D8Xd/edM3mhO9nRpUXRK9Bvt4iEZUXGuVtZLT52nK6Wv2EZ1TiT OiqZlf1P+vxYLBx9eKmabPdm3yjalhY8yr1S1vL0gSA/C6W1o/TowdieF1rWN/MYHlkpyj9c Rpc281gAO0AP3V1G00YzBEdYyi0gaJbCEQnq8Vz1vDXFxHzyhgGz7umBsVKmYwZgA8DrrB0M oaP35wuGR3RJcaG30AnJpEDkBYHznI2apxdcuTPOHZyEilIRrBGzDwGtAhldzlBoBwE3Z3MY 31TOpACu1ZpNOMysZ6xiE35pWkwc0KYm4hJA5GFfmWSN6DniimW3pmdDIiw4Ifcx8b3mFrRO BbDIW13E51j9RjbO/nAaK9ndZ5LRO1B/8Fwat7bLzmsCiEXOJY7NNpIEpkoNoEUfCcZwmLrU +eOTPzaF6drw6ayewEi5yzPg3TAT6FV3oBsNg3xlwU0gPK3v6gYPX5w9+ovPZ1/qqNfOrbsE FRuiSVsZQ5s3AAMFD/9XjlnnVDh9GX/r/6hjmr4U9tEsM+VQXaVXqZuHKaSmojOLUCP/YVQo 7IiYaNssCS4FCPe4yrL4FJJfJAsbeyDykMN7wAnBcOkbZ9BPJPNCbqU6dowLOiy8AuTYQ48m vIyQ4Ijnb6GTrtxIUDQeOBNuQC/gyyx3nbL/lVlHbxr4tb6YkhkO6shjXhQh7nQb33FjGO4P WU11Nr9i/qoV8QCo12MQEo244RRA6VMud06y/E449rWZFSTwGqb0FS0seTcYNvxt8PB2izX+ HZA8SL54j479ubxhfuoTu5nXdtFYFj5Lj5x34LKPx7MpgAmj0H7SDhpFWF2FzcC1bjiW9mjW HaKaX23Awt97AqQZXegbfkJwX2Y53ufq8Np3e1542lh3/mpiGSilCsaTahEGrHK+lIusl6mz Joil+u3k01ofvJMK0ZdzGUZ/aPMZ16LofjFA+MNxWrZFrkYmiGdv+LG45zSlZyIvzSiG2lKy kuVag+IijCIom78P9jRtB1q1Q5lwZp2TLAJlz92DmFwBg1hyFzwDADjZ2nrDxKUiybXIgZp9 aU2d++ptEGCVJOfEW4qpWCCLPbOT7XBr+g/4H3qWbs3j/cDDq7LuVYIe+wchy/iXEJaQVeTC y5arMQorqTFWlEOgRA8OP47L9knl9i4xuR0euV6DChDrguup2aJVU4hPBBgRAgAPAhsMBQJU X9LxBQkeXB3fAAoJEGFXmRW1Y3YOj4UAn3nrFLPZekMeqX5aD/aq/dsbXSfyAKC45Go0YyxV HGuUuzv+GKZ6nsysJ7kCDQRXG8fwARAA6q/pqBi5PjHcOAUgk2/2LR5LjjesK50bCaD4JuNc YDhFR7Vs108diBtsho3w8WRd9viOqDrhLJTroVckkk74OY8r+3t1E0Dd4wHWHQZsAeUvOwDM PQMqTUBFuMi6ydzTZpFA2wBR9x6ofl8Ax+zaGBcFrRlQnhsuXLnM1uuvS39+pmzIjasZBP2H UPk5ifigXcpelKmj6iskP3c8QN6x6GjUSmYx+xUfs/GNVSU1XOZn61wgPDbgINJd/THGdqiO iJxCLuTMqlSsmh1+E1dSdfYkCb93R/0ZHvMKWlAx7MnaFgBfsG8FqNtZu3PCLfizyVYYjXbV WO1A23riZKqwrSJAATo5iTS65BuYxrFsFNPrf7TitM8E76BEBZk0OZBvZxMuOs6Z1qI8YKVK UrHVGFq3NbuPWCdRul9SX3VfOunr9Gv0GABnJ0ET+K7nspax0xqq7zgnM71QEaiaH17IFYGS sG34V7Wo3vyQzsk7qLf9Ajno0DhJ+VX43g8+AjxOMNVrGCt9RNXSBVpyv2AMTlWCdJ5KI6V4 KEzWM4HJm7QlNKE6RPoBxJVbSQLPd9St3h7mxLcne4l7NK9eNgNnneT7QZL8fL//s9K8Ns1W t60uQNYvbhKDG7+/yLcmJgjF74XkGvxCmTA1rW2bsUriM533nG9gAOUFQjURkwI8jvMAEQEA AYkCaAQYEQIACQUCVxvH8AIbAgIpCRBhV5kVtWN2DsFdIAQZAQIABgUCVxvH8AAKCRCH0Jac RAcHBIkHD/9nmfog7X2ZXMzL9ktT++7x+W/QBrSTCTmq8PK+69+INN1ZDOrY8uz6htfTLV9+ e2W6G8/7zIvODuHk7r+yQ585XbplgP0V5Xc8iBHdBgXbqnY5zBrcH+Q/oQ2STalEvaGHqNoD UGyLQ/fiKoLZTPMur57Fy1c9rTuKiSdMgnT0FPfWVDfpR2Ds0gpqWePlRuRGOoCln5GnREA/ 2MW2rWf+CO9kbIR+66j8b4RUJqIK3dWn9xbENh/aqxfonGTCZQ2zC4sLd25DQA4w1itPo+f5 V/SQxuhnlQkTOCdJ7b/mby/pNRz1lsLkjnXueLILj7gNjwTabZXYtL16z24qkDTI1x3g98R/ xunb3/fQwR8FY5/zRvXJq5us/nLvIvOmVwZFkwXc+AF+LSIajqQz9XbXeIP/BDjlBNXRZNdo dVuSU51ENcMcilPr2EUnqEAqeczsCGpnvRCLfVQeSZr2L9N4svNhhfPOEscYhhpHTh0VPyxI pPBNKq+byuYPMyk3nj814NKhImK0O4gTyCK9b+gZAVvQcYAXvSouCnTZeJRrNHJFTgTgu6E0 caxTGgc5zzQHeX67eMzrGomG3ZnIxmd1sAbgvJUDaD2GrYlulfwGWwWyTNbWRvMighVdPkSF 6XFgQaosWxkV0OELLy2N485YrTr2Uq64VKyxpncLh50e2RnyAJ9Za0Dx0yyp44iD1OvHtkEI M5kY0ACeNhCZJvZ5g4C2Lc9fcTHu8jxmEkI= Message-ID: Date: Tue, 10 Sep 2019 12:01:01 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 9/10/19 1:35 AM, Jose Abreu wrote: > From: Thierry Reding > Date: Sep/09/2019, 20:13:29 (UTC+00:00) > >> On Mon, Sep 09, 2019 at 04:05:52PM +0000, Jose Abreu wrote: >>> From: Thierry Reding >>> Date: Sep/09/2019, 16:25:46 (UTC+00:00) >>> >>>> @@ -79,6 +79,10 @@ static void dwmac4_dma_init_rx_chan(void __iomem *ioaddr, >>>> value = value | (rxpbl << DMA_BUS_MODE_RPBL_SHIFT); >>>> writel(value, ioaddr + DMA_CHAN_RX_CONTROL(chan)); >>>> >>>> + if (dma_cfg->eame) >>> >>> There is no need for this check. If EAME is not enabled then upper 32 >>> bits will be zero. >> >> The idea here was to potentially guard against this register not being >> available on some revisions. Having the check here would avoid access to >> the register if the device doesn't support enhanced addressing. > > I see your point but I don't think there will be any problems unless you > have some strange system that doesn't handle the write accesses to > unimplemented features properly ... Is not it then just safer to not do the write to a register that you do not know how the implementation is going to respond to with one of a target abort, timeout, decoding error, just dead lock? Also, would it make sense to consider adding an #ifdef CONFIG_PHYS_ADDR_T_64BIT plus the conditional check so that you can be slightly more optimal in the hot-path here? -- Florian