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=-2.2 required=3.0 tests=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 A67A0C2D0DB for ; Tue, 28 Jan 2020 13:33:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8526624686 for ; Tue, 28 Jan 2020 13:33:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726129AbgA1Ndw (ORCPT ); Tue, 28 Jan 2020 08:33:52 -0500 Received: from lhrrgout.huawei.com ([185.176.76.210]:2315 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725852AbgA1Ndw (ORCPT ); Tue, 28 Jan 2020 08:33:52 -0500 Received: from lhreml706-cah.china.huawei.com (unknown [172.18.7.107]) by Forcepoint Email with ESMTP id 3CA825C12289569A1C47; Tue, 28 Jan 2020 13:33:50 +0000 (GMT) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by lhreml706-cah.china.huawei.com (10.201.108.47) with Microsoft SMTP Server (TLS) id 14.3.408.0; Tue, 28 Jan 2020 13:33:49 +0000 Received: from [127.0.0.1] (10.202.226.43) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5; Tue, 28 Jan 2020 13:33:49 +0000 Subject: Re: [PATCH RFC 2/2] soc: Add a basic ACPI generic driver To: Greg KH CC: , , , , , , , References: <1580210059-199540-1-git-send-email-john.garry@huawei.com> <1580210059-199540-3-git-send-email-john.garry@huawei.com> <20200128115629.GB2680602@kroah.com> From: John Garry Message-ID: Date: Tue, 28 Jan 2020 13:33:48 +0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.1.2 MIME-Version: 1.0 In-Reply-To: <20200128115629.GB2680602@kroah.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.226.43] X-ClientProxiedBy: lhreml732-chm.china.huawei.com (10.201.108.83) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Hi Greg, >> + >> +#define pr_fmt(fmt) "SOC ACPI GENERIC: " fmt > > You have a device, why do you need pr_fmt()? > The only print in the code can be removed, below, so I need not worry about this, i.e. remove it. >> + >> +#include >> +#include >> + >> +/* >> + * Known platforms that fill in PPTT package ID structures according to >> + * ACPI spec examples, that being: >> + * - Custom driver attribute is in ID Type Structure VENDOR_ID member >> + * - SoC id is in ID Type Structure LEVEL_2_ID member >> + * See ACPI SPEC 6.2 Table 5-154 for PPTT ID Type Structure >> + */ >> +static struct acpi_platform_list plat_list[] = { >> + {"HISI ", "HIP08 ", 0, ACPI_SIG_PPTT, all_versions}, >> + { } /* End */ >> +}; >> + >> +struct acpi_generic_soc_struct { >> + struct soc_device_attribute dev_attr; >> + u32 vendor; >> +}; >> + >> +static ssize_t vendor_show(struct device *dev, >> + struct device_attribute *attr, >> + char *buf) >> +{ >> + struct acpi_generic_soc_struct *soc = dev_get_drvdata(dev); >> + u8 vendor_id[5] = {}; >> + >> + *(u32 *)vendor_id = soc->vendor; >> + >> + return sprintf(buf, "%s\n", vendor_id); >> +} >> + >> +static DEVICE_ATTR_RO(vendor); >> + >> +static __init int soc_acpi_generic_init(void) >> +{ >> + int index; >> + >> + index = acpi_match_platform_list(plat_list); >> + if (index < 0) >> + return -ENOENT; >> + >> + index = 0; >> + while (true) { >> + struct acpi_pptt_package_info info; >> + >> + if (!acpi_pptt_get_package_info(index, &info)) { >> + struct soc_device_attribute *soc_dev_attr; >> + struct acpi_generic_soc_struct *soc; >> + struct soc_device *soc_dev; >> + u8 soc_id[9] = {}; >> + >> + *(u64 *)soc_id = info.LEVEL_2_ID; >> + >> + soc = kzalloc(sizeof(*soc), GFP_KERNEL); >> + if (!soc) >> + return -ENOMEM; >> + >> + soc_dev_attr = &soc->dev_attr; >> + soc_dev_attr->soc_id = kasprintf(GFP_KERNEL, "%s", >> + soc_id); >> + if (!soc_dev_attr->soc_id) { >> + kfree(soc); >> + return -ENOMEM; >> + } >> + soc->vendor = info.vendor_id; >> + >> + soc_dev = soc_device_register(soc_dev_attr); >> + if (IS_ERR(soc_dev)) { >> + int ret = PTR_ERR(soc_dev); >> + >> + pr_info("could not register soc (%d) index=%d\n", >> + ret, index); > > pr_err()? Yes, more appropriate. > > And shouldn't the core print out the error, not the person who calls it? Sure, that would sounds reasonable, but I just wanted to get the index at which we fail. I could live without it. > > >> + kfree(soc_dev_attr->soc_id); >> + kfree(soc); >> + return ret; >> + } >> + dev_set_drvdata(soc_device_to_device(soc_dev), soc); >> + device_create_file(soc_device_to_device(soc_dev), >> + &dev_attr_vendor); > > You just raced with userspace and lost. Use the built-in api that I > made _just_ because of SOC drivers to do this correctly. > Fine, there is the soc device custom attr group which I can use. But, as Arnd said, maybe we can drop this custom file. Cheers, John