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=-7.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED autolearn=ham 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 1341DC282C0 for ; Fri, 25 Jan 2019 22:28:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C1BBB218D0 for ; Fri, 25 Jan 2019 22:28:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="mesVDQ5C" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729388AbfAYW2t (ORCPT ); Fri, 25 Jan 2019 17:28:49 -0500 Received: from mail-pl1-f195.google.com ([209.85.214.195]:36254 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726311AbfAYW2t (ORCPT ); Fri, 25 Jan 2019 17:28:49 -0500 Received: by mail-pl1-f195.google.com with SMTP id g9so5180207plo.3 for ; Fri, 25 Jan 2019 14:28:48 -0800 (PST) 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=A7RLWj1i4+J2/F9RwhvQ7RM9Jj8SQ28Ke7DmtNjgsvU=; b=mesVDQ5CCHFVzXH8R4BYKzkWL6CShtxefd7mYHd2fbzs4rjGuySn4x+veFAiqYz7b5 TjRttZ4PxVsJSBfQB+PL7e3Aajgz2uz3J90/PkzWsXq4V+mHSsB0hC9DuSNbOxSY5Asr DM1IIVZLEFlEbi7uPMASckreimNCax39dFyHZQdNW6x1ZhqLiF7CWs5VWZtEly/7iXqp P8EAePOxAKRve2Gfqt7iKD/6uQcuG+itxeObAZ2GVNAwx5Q5kKmgo6QzX6p2qhGYhfPg oAojhg1sD+kBsHePSV45ZZGRTz4r2NGJTqpXN7tlFNSil+3cBb2vPVRfh6+MZv4N+i8W higQ== 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=A7RLWj1i4+J2/F9RwhvQ7RM9Jj8SQ28Ke7DmtNjgsvU=; b=UPSQgToZzkfSRlesMtQaEiK3s0mDy4aTKVeOxC7V6On+a0kPhI7RX0GCHanQcYLoFL ObvcwdmKgSSAc10r/1o2hehMByJBRVVSeDLyWeQawbDQmPx6y/ZJAPQxEz2Aw5GEpLkp V1pC4T9dVLNxa3214xGtbl1l5z3cIui8LpdwXBVGE4AQaHd8ZY/hDhbVIgg7lY1PhO1X AHASCVo4k+Zd32TDpsjUqzcL+lWKdlMI2XTeCCJm5xkmnR5fC5yRgIc4qxJfjyQT/sf9 eImchq+OpDGKV6eHCcS+ibo47PYka8EP8ha7mE7fQG0YPqihC2PJ6ypEMVLwerpA2nOG EZWA== X-Gm-Message-State: AJcUukd7v5jtBQiy3nYFU2eZe8Qcw4Fx14kDTyYMOrsnAggcZULiLfKA 365d2GMl60bS9eA/Kb0PC61BHfZ6 X-Google-Smtp-Source: ALg8bN4LAtFjRadmhc4IqLph28qIg4TgsCnfYB3R7ZEUhcFuVs+ghW/Z9pqb6MKq/JArOsehWmO+Vg== X-Received: by 2002:a17:902:a70b:: with SMTP id w11mr12740226plq.84.1548455327653; Fri, 25 Jan 2019 14:28:47 -0800 (PST) Received: from [10.67.49.9] ([192.19.223.250]) by smtp.googlemail.com with ESMTPSA id o66sm42488055pgo.75.2019.01.25.14.28.46 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 25 Jan 2019 14:28:46 -0800 (PST) Subject: Re: [PATCH] sfp: sfp_read: split-up request when hw rx buffer is too small. To: =?UTF-8?Q?Ren=c3=a9_van_Dorst?= Cc: Andrew Lunn , Heiner Kallweit , "David S. Miller" , netdev@vger.kernel.org References: <20190123212046.13020-1-opensource@vdorst.com> <20190124131510.Horde.4Vz5bPgjqn22MgFWZL3Txy_@www.vdorst.com> <20190125215843.Horde.8SasDoteCejPU5IfJ0ibweV@www.vdorst.com> 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: <25fe50ef-d9f5-4a15-5f42-faf8b012416a@gmail.com> Date: Fri, 25 Jan 2019 14:28:39 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20190125215843.Horde.8SasDoteCejPU5IfJ0ibweV@www.vdorst.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 1/25/19 1:58 PM, René van Dorst wrote: > Quoting René van Dorst : > >> Quoting Florian Fainelli : >> >>> On 1/23/19 1:20 PM, René van Dorst wrote: >>>> Without this patch sfp code retries to read the full struct >>>> sfp_eeprom_id >>>> id out of the SFP eeprom. Sizeof(id) is 96 bytes. >>>> My i2c hardware, Mediatek mt7621, has a rx buffer of 64 bytes. >>>> So sfp_read gets -NOSUPPORTED back on his turn return -EAGAIN. >>>> Same issue is with the SFP_EXT_STATUS data which is 92 bytes. >>>> >>>> By split-up the request in multiple smaller requests with a max size >>>> of i2c >>>> max_read_len, we can readout the SFP module successfully. >>>> >>>> Tested with MT7621 and two Fiberstore modules SFP-GB-GE-T and >>>> SFP-GE-BX. >>>> >>>> Signed-off-by: René van Dorst >>>> --- >>>> drivers/net/phy/sfp.c | 23 ++++++++++++++++++++++- >>>> 1 file changed, 22 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/drivers/net/phy/sfp.c b/drivers/net/phy/sfp.c >>>> index fd8bb998ae52..1352a19571cd 100644 >>>> --- a/drivers/net/phy/sfp.c >>>> +++ b/drivers/net/phy/sfp.c >>>> @@ -367,7 +367,28 @@ static void sfp_set_state(struct sfp *sfp, >>>> unsigned int state) >>>> >>>> static int sfp_read(struct sfp *sfp, bool a2, u8 addr, void *buf, >>>> size_t len) >>>> { >>>> -    return sfp->read(sfp, a2, addr, buf, len); >>>> +    const struct i2c_adapter_quirks *q = sfp->i2c->quirks; >>>> +    int ret; >>>> +    size_t rx_bytes = 0; >>>> + >>>> +    /* Many i2c hw have limited rx buffers, split-up request when >>>> needed. */ >>>> +    while ((q->max_read_len) && (len > q->max_read_len)) { >>>> +        ret = sfp->read(sfp, a2, addr, buf, q->max_read_len); >>>> +        if (ret < 0) >>>> +            return ret; >>>> +        rx_bytes += ret; >>>> +        addr += q->max_read_len; >>>> +        buf += q->max_read_len; >>>> +        len -= q->max_read_len; >>>> +    } >>> >>> sfp->read defaults to sfp_i2c_read() but it is possible to override that >>> by registering a custom sfp_bus instance (nothing does it today, but >>> that could obviously change), so there is no guarantee that >>> sfp->i2c->quirks is applicable unless sfp_i2c_read() is used. >>> >>> sfp_i2c_read() is presumably where the max_read_len splitting should >>> occur, or better yet, should not i2c_transfer() take care of that on its >>> own? That way there would be no layering violation of having to fetch >>> the quirk bitmask for the i2c adapter being used, that is something that >>> should belong in the core i2c framework. >> >> Yes it is better to put it in sfp_i2c_read(). >> >> I think it is best to handle the split-up within the driver. >> The driver knows how to talk to the device and may apply device quirks. >> >> Also tda1004x [0] and TPM [1] driver also handles it within the driver >> itself. >> >> TPM driver just try to send the want size and split-up request to >> I2C_SMBUS_BLOCK_MAX when a -EOPNOTSUPP returns, just retries it a >> number of >> times. >> >> I can do the same but I have to pick a minimum size. >> Looking in SSF-8472rev12.2.1 they don't limit the way you access the >> device. >> So use I2C_SMBUS_BLOCK_MAX of 32 bytes is sufficient or lookup the i2c >> quirk max_read_len is also an option. > > Hi Florian, > > I did a test in sfp_i2c_read() with reducing the read size when -EOPNOTSUPP > returns like TPM driver. But this always produces noise in kernel log about > the "msg too long" if the device is init at boot or when plugged-in. > Devices with SFP_EXT_STATUS generates also an 2nd error. > So I prefer to use the quirk max_read_len. My point still stands, we have an abstraction layer through the i2c core which sits between clients and adapters. If you have a simple read into a buffer transaction (like what we have here), then you can provide a safe accessor function that takes care of looking at the max_read_len quirk and splitting things into the appropriate number of transaction. Then we can also eliminate the "msg too long" annoying message since we are now using an appropriate function. The fact that there are multiple drivers that need to be patched to split i2c transaction is an indication that this is not IMHO addressed at the right level, especially if what they do is as simple as an i2c_transfer() into a single buffer and require no quirky transaction. Andrew, Heiner and Russell might have a different view on this. > > dmesg output reduce read size when -EOPNOTSUPP returns. > [  134.220000] i2c i2c-0: adapter quirk: msg too long (addr 0x0050, size > 96, read) > [  135.250000] sfp sfp-lan5: module FiberStore       SFP-GB-GE-T      > rev B    sn       dc > [  141.150000] sfp sfp-lan5: module removed > [  150.950000] i2c i2c-0: adapter quirk: msg too long (addr 0x0050, size > 96, read) > [  151.980000] sfp sfp-lan5: module FiberStore       SFP-GE-BX        > rev A0   sn       dc > [  151.990000] i2c i2c-0: adapter quirk: msg too long (addr 0x0051, size > 92, read) > > dmesg output with read size always reduced to quiek max_read_len. > [   27.350000] sfp sfp-lan5: module FiberStore       SFP-GE-BX        > rev A0   sn       dc > [   34.540000] sfp sfp-lan5: module removed > [   39.360000] sfp sfp-lan5: module FiberStore       SFP-GB-GE-T      > rev B    sn       dc > > So shall I spin v2 with quirk max_read_len as max read size? -- Florian