Received: by 2002:ac0:a582:0:0:0:0:0 with SMTP id m2-v6csp3766984imm; Mon, 15 Oct 2018 03:58:25 -0700 (PDT) X-Google-Smtp-Source: ACcGV638K1gxcTPI/rs7op0oZv1Qm5y8yR+VRKgGZhytGiur88UXdqKF0eR4aH22sfxI24vyn4Nh X-Received: by 2002:a62:f909:: with SMTP id o9-v6mr17170647pfh.160.1539601105159; Mon, 15 Oct 2018 03:58:25 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1539601105; cv=none; d=google.com; s=arc-20160816; b=IEdusvm8nQ7iXdfpO8EwIW9ttfhOMGAYSkV2bcd6SMCjjPdjZ8ErV9XUIpoSPwwlwq 6zj9TVDq9IaOoNyQxJprCqzN2UsMXASfGAcpa8aF8tICL8F9l8FW8iqbxKeh0lD0nEh2 P59wUZdbEt8otL033skdB3g5F1C9oXRLc3MKmdilFxhwyipe5//4XpjzDKxRpZ0o+G8O eZ4EGuv6CawMsndgZvjee4hgC4USDBtTgxWU8/r0ecTRxlwmJpxomHEB73IYBoI/Jx30 TxY3Es4ZIweYwsLb7Rcp6fHUPiJhMdw8ML/9HFMbZ6WElIqkianC0xa743zVGwzAZ/jp kYDA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-language :content-transfer-encoding:in-reply-to:mime-version:user-agent:date :message-id:from:references:cc:to:subject:dmarc-filter :dkim-signature:dkim-signature; bh=1O5umhf/kXVwEkddg/3pQTZikH7GAEVO2CYUgPvMYGs=; b=tjxHp8ROlXTZ17o9Z+yr/AWUf8uOvDxA62BOcxCxUJD+Agl3jtMSuiqSphFRuVNwuC atM0cdQ7l5jgb91jB40ZsWaXgwl1r9/t7PK2lQtMEXocHHIWXnrXLLhdwIDrcx6vQR0n F4P6qzhmIMvQTYdJIpQR4M1HJd+6Pc885Ztm7RT+cIEZJ7zlAgHSRHpNay99Oo4wsQo8 +dxn0W7O0BEtlY6yPhMAAi1RJgYsOTTHH/UPouUmdTVL14nuxZOGNzfymfP6aDSAaeAO jfNvsS4RDzU9p+mt5cTzNRTP20ZFe9itiMLVQJyjyztkHuk2XdDTqMftS6ExvKapW40o pYNQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@codeaurora.org header.s=default header.b=E8DJjl63; dkim=pass header.i=@codeaurora.org header.s=default header.b=d9vB84Pk; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id k9-v6si10197409pgi.227.2018.10.15.03.58.10; Mon, 15 Oct 2018 03:58:25 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@codeaurora.org header.s=default header.b=E8DJjl63; dkim=pass header.i=@codeaurora.org header.s=default header.b=d9vB84Pk; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726638AbeJOSmD (ORCPT + 99 others); Mon, 15 Oct 2018 14:42:03 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:59584 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726273AbeJOSmC (ORCPT ); Mon, 15 Oct 2018 14:42:02 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 7A109612F6; Mon, 15 Oct 2018 10:57:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1539601037; bh=TWfSBoQ0mxq8cg7ulnTwJYxl89tQRs/UpCsUSkomiRg=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=E8DJjl63iNyq6ow2wzeb3RUiIeqGIXGIg+MMCeTdC1SllacSf2WHHaoMnYq9eai4P 3MPE9+5r70SobsHn+on1B7rciO+fkgZ1xF31tJtD7Z2X2LAB38BhZsqf8kD3EBsiho N0FnlhRFMKWcVtJ1gwLwjkUqupfaEPWYjgzYn3eE= X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on pdx-caf-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.7 required=2.0 tests=ALL_TRUSTED,BAYES_00, DKIM_INVALID,DKIM_SIGNED autolearn=no autolearn_force=no version=3.4.0 Received: from [10.206.24.177] (blr-c-bdr-fw-01_globalnat_allzones-outside.qualcomm.com [103.229.19.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: sayalil@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id 2CEAC604BE; Mon, 15 Oct 2018 10:57:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1539601036; bh=TWfSBoQ0mxq8cg7ulnTwJYxl89tQRs/UpCsUSkomiRg=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=d9vB84PkKqeZ1utzqjv6hih0i5bse7FokizGKAiRJN1Mg6/D83RsoGL1cf0+bMJT/ 3wnbBTnZVeYfsX9rou6027gItYZv/YtJg+3K09r2Yx4mcmm5hbAsERQV4bfMB8STsT 48n4IxZ07owcFIKtDGLtZ5kKHph6hLOWOReUCNdU= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 2CEAC604BE Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=sayalil@codeaurora.org Subject: Re: [PATCH V14 1/2] scsi: ufs: set the device reference clock setting To: Doug Anderson Cc: subhashj@codeaurora.org, cang@codeaurora.org, Vivek Gautam , Rajendra Nayak , Vinayak Holikatti , jejb@linux.vnet.ibm.com, "Martin K. Petersen" , Asutosh Das , Evan Green , riteshh@codeaurora.org, stummala@codeaurora.org, Adrian Hunter , jlbec@evilplan.org, linux-scsi@vger.kernel.org, LKML References: <1537770516-28410-1-git-send-email-sayalil@codeaurora.org> <1537770516-28410-2-git-send-email-sayalil@codeaurora.org> From: Sayali Lokhande Message-ID: <5c08dcb3-f5e2-47f3-a75d-46802643250a@codeaurora.org> Date: Mon, 15 Oct 2018 16:27:08 +0530 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi On 10/13/2018 4:20 AM, Doug Anderson wrote: > Hi, > > On Sun, Sep 23, 2018 at 11:29 PM Sayali Lokhande wrote: >> +static struct ufs_ref_clk ufs_ref_clk_freqs[] = { >> + {19200000, REF_CLK_FREQ_19_2_MHZ}, >> + {26000000, REF_CLK_FREQ_26_MHZ}, >> + {38400000, REF_CLK_FREQ_38_4_MHZ}, >> + {52000000, REF_CLK_FREQ_52_MHZ}, >> + {0, REF_CLK_FREQ_INVAL}, >> +}; >> + >> +static inline enum ufs_ref_clk_freq > Please don't specify inline. Let the compiler decide whether inline is better. Done > >> +ufs_get_bref_clk_from_hz(u32 freq) >> +{ >> + int i = 0; >> + >> + while (ufs_ref_clk_freqs[i].freq_hz != freq) { >> + if (!ufs_ref_clk_freqs[i].freq_hz) >> + return REF_CLK_FREQ_INVAL; >> + i++; >> + } >> + >> + return ufs_ref_clk_freqs[i].val; > I think you'll have less confusion if you write the above as this (untested): > > for (i = 0; ufs_ref_clk_freqs[i].freq_hz; i++) { > if (ufs_ref_clk_freqs[i].freq_hz == freq) > return ufs_ref_clk_freqs[i].val; > } > > return REF_CLK_FREQ_INVAL; > > Now it looks like a normal iteration till a normal stop condition > (NULL term array). > Will update. >> +void ufshcd_parse_dev_ref_clk_freq(struct ufs_hba *hba) > Shouldn't this return an error code so that if there's a problem it > can return back to the caller? Right now you print error messages but > ufshcd_pltfrm_init() will plow merrily along after. We need not return error if no specific device ref clk was found via DT parsing. Device reference clock will be already set(bRefClkFreq MDV : 26MHz). So no need to fail if we find invalid/no ref clk passed. > >> +{ >> + struct device *dev = hba->dev; >> + struct device_node *np = dev->of_node; >> + struct clk *refclk = NULL; >> + u32 freq = 0; > "freq" should be "unsigned long" to match clk_get_rate(), not u32. > Similarly all the places you pass it to and store it in should be > "unsigned long" too. Save "u32" for values which are being programmed > into 32-bit hardware registers. > Will update. >> + if (!np) >> + return; > You don't need to check for (!np). If you do clk_get() and there's no > np you'll get get an error back. Handle it there. > Will update. >> + >> + refclk = of_clk_get_by_name(np, "ref_clk"); >> + if (!refclk) >> + return; > I can't quickly tell. Are you intending "ref_clk" to be optional or > required? You check against "NULL" and return with no error message, > so I'm kinda assuming it's optional. ...but: Explicit setting of device reference clock is not mandatory. It will be already set (MDV: 26Hz). We first read the current ref clk setting in device and if host is passing different (but valid) ref clk freq then we go ahead and update it, otherwise we just return. > 1. of_clk_get_by_name() doesn't return NULL when the clock wasn't > specified. It returns "-ENOENT". That means that (right now) anyone > who doesn't specify a "ref_clk" will get a crash when you try calling > clk_get_rate() on the error-code-clk. > > 2. It seems like it would be good to add a comment that > "dev_ref_clk_freq" was already initted to "REF_CLK_FREQ_INVAL in > ufshcd_alloc_host() to make it obvious how people are working that > didn't specify "ref_clk". Will add comment to clarify that dev_ref_clk_freq is default set as REF_CLK_FREQ_INVA. > > One note is that regardless of whether "ref_clk" is optional or > required, something about "ref_clk" should be mentioned in > "Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt" so people > know that's an important clock name. > Will check and add required documentation. > Yet another note here is that I'm confused why you'd want to use > of_clk_get_by_name(). Why not use clk_get()? You've already got the > "dev" node and clk_get() should be preferred since not everyone uses > device tree. Will update. > > OK, one last note is that clk_get() could return -EPROBE_DEFER. In > such a case you need to basically cancel your whole probe and > propagate the -EPROBE_DEFER. Make sure you think about that when > you're coding things up. > > > OK, I lied about the previous one being the last note. Why don't you > just add a bit of code in the ufshcd_init_clocks() loop. If you > notice that the clock name is "ref_clk" (similar to how > __ufshcd_setup_clocks() checks) then you can grab the frequency. Then > you can avoid dealing with all my comments above about > of_clk_get_by_name() and errors and -EPROBE_DEFER... > Will consider above suggestion and update. May be I can just call ufshcd_parse_dev_ref_clk_freq (hba, ref_clk) from ufshcd_init_clocks() loop and pass ref_clk to it. >> + freq = clk_get_rate(refclk); >> + >> + hba->dev_ref_clk_freq = >> + ufs_get_bref_clk_from_hz(freq); >> + >> + if (hba->dev_ref_clk_freq == REF_CLK_FREQ_INVAL) >> + dev_err(hba->dev, >> + "%s: invalid ref_clk setting = %d\n", >> + __func__, freq); > nit: including "__func__" in dev_xxx() calls is discouraged. The > "dev_xxx" calls already print the device name and the string within a > given device driver should be unique enough so __func__ just adds crap > to the logs. If you really feel that __func__ adds something for you, > try posting up a patch to make all "dev_err" functions include > __func__. ...but I think you'd probably be rejected. will remove __func__ . > > Also (more important): You're missing a clk_put(). Thus you're > leaking a reference to "ref_clk". > > >> +} >> + >> +static int ufshcd_set_dev_ref_clk(struct ufs_hba *hba) >> +{ >> + int err, ref_clk = -1; >> + u32 freq = hba->dev_ref_clk_freq; > Ugh, this is ugly. hba->dev_ref_clk_freq could be -1 but you're > jamming it into a u32 here. That doesn't seem so ideal. Are you sure > -1 was the best choice for REF_CLK_FREQ_INVAL? ufshcd_set_dev_ref_clk() is only called if  (dev_ref_clk_freq != REF_CLK_FREQ_INVAL). So we only set freq if we get a valid parsed ref clk freq (0/1/2/3h). > >> + >> + err = ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_READ_ATTR, >> + QUERY_ATTR_IDN_REF_CLK_FREQ, 0, 0, &ref_clk); > It's not so wonderful to be passing a pointer to an "int" to a > function expecting a pointer to a "u32". Change "ref_clk" to "u32". done > >> + >> + if (err) { >> + dev_err(hba->dev, "%s: failed reading bRefClkFreq. err = %d\n", >> + __func__, err); > Again, no __func__. > Will remove __func__ >> + goto out; >> + } >> + >> + if (ref_clk == hba->dev_ref_clk_freq) > nit: you already cached "hba->dev_ref_clk_freq in "freq". Use it. Will update > >> + goto out; /* nothing to update */ >> + >> + err = ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_WRITE_ATTR, >> + QUERY_ATTR_IDN_REF_CLK_FREQ, 0, 0, &freq); >> + >> + if (err) { >> + dev_err(hba->dev, "%s: bRefClkFreq setting to %u Hz failed\n", >> + __func__, ufs_ref_clk_freqs[freq].freq_hz); > Again, no __func__. > Will remove __func__ >> + goto out; >> + } >> + >> + dev_dbg(hba->dev, "%s: bRefClkFreq setting to %u Hz succeeded\n", >> + __func__, ufs_ref_clk_freqs[freq].freq_hz); > Again, no __func__. Will remove __func__