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=-0.6 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, URIBL_BLOCKED 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 45C84C47254 for ; Tue, 5 May 2020 13:49:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 11A7D206A5 for ; Tue, 5 May 2020 13:49:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="lYXFjuSE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728268AbgEENt6 (ORCPT ); Tue, 5 May 2020 09:49:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44718 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1728180AbgEENt6 (ORCPT ); Tue, 5 May 2020 09:49:58 -0400 Received: from mail-pg1-x544.google.com (mail-pg1-x544.google.com [IPv6:2607:f8b0:4864:20::544]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 34F81C061A0F; Tue, 5 May 2020 06:49:58 -0700 (PDT) Received: by mail-pg1-x544.google.com with SMTP id j21so1045683pgb.7; Tue, 05 May 2020 06:49:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=9MCIO2OCfMOgmV5WblJ/wi27KouMeCD72GUlRx7Mb+U=; b=lYXFjuSEZ4adi7eHR0YNXLGvq1LdV3DVgdyuGbLYR/w4rHXXccdvf4YLmlBQNKX/0d u1Jj124H0EvE3WsYlxIiZVLPSIgpACDohDmsvOAiHSNTx721tSx2gKvKTu/vvaczOSXd ON+d0rpMccVye8GPS/8Ud9oQUbXN/bBkBj0JbyLzZAwdd4C8QlYdYqw5OHZRj034VmTA TkjsX1rg5TID1NYAIAizVjigOC0rtPhFuSxmpVzLPWNd1QtLkx5RVTMK8+SOp9RzLpG+ bDshL/yqRl/K8TlZXtCPssIABxehIoWVUj9d8Xl6QdEDrAYmXupJPDJE7c9IahntKT2V MP3w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=9MCIO2OCfMOgmV5WblJ/wi27KouMeCD72GUlRx7Mb+U=; b=mdZwIs068b6A/mjqB1AshCbqm86nI6Ldywy7Ebw6zANzqa60QHxD2CnYsv2T2pXH0G Ut2Z96O71DS1Nh2k/3mUq8ITctoRhhWfFiIueHr1Tk05b790YwO/xQBj2R+Iv7W3HUP/ oezZ56urZIFbCxpIGaWXocCmSq9HPEpISDX7p2gnSFzdovh83ghpmLWNyPhzLZjO7u+I y/1cuqmleqLx6syeVU8Nc2fZnO/5GmK5Tg9VgSBCTQO/PZLLfeq3hbMZzhwSwUGUQzyv 3SEY+M9nk9NayM1VlV2yxYO92AJJd9uSlraP9dDqdvq9/VYiHs9jtx46PpiZ3oOeqB2N breA== X-Gm-Message-State: AGi0PuZ9TJ1tabC3m5xa1Kp93s6gd7azIonpTj4UuTeS/GrQ1wCXxBCJ pyyi7lJCi/rGhefQmfVy5KfcI1ajpyVnBnztmq916RBZUGs= X-Google-Smtp-Source: APiQypLEjjkNBYqDj1xIa1IS20Q1twTdcOnA68o6+brisIVbghPEqqR8qaQvl3R23uiKsniAbHKbPYMgjmDuIoyZm6Y= X-Received: by 2002:a62:5ec7:: with SMTP id s190mr3158550pfb.130.1588686597629; Tue, 05 May 2020 06:49:57 -0700 (PDT) MIME-Version: 1.0 References: <20200505013206.11223-1-david.e.box@linux.intel.com> <20200505023149.11630-1-david.e.box@linux.intel.com> <20200505023149.11630-2-david.e.box@linux.intel.com> In-Reply-To: <20200505023149.11630-2-david.e.box@linux.intel.com> From: Andy Shevchenko Date: Tue, 5 May 2020 16:49:50 +0300 Message-ID: Subject: Re: [PATCH 3/3] platform/x86: Intel PMT Telemetry capability driver To: "David E. Box" Cc: Bjorn Helgaas , Andy Shevchenko , alexander.h.duyck@intel.com, Linux Kernel Mailing List , linux-pci@vger.kernel.org, Alexander Duyck Content-Type: text/plain; charset="UTF-8" Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Tue, May 5, 2020 at 5:32 AM David E. Box wrote: ... > Register mappings are not provided by the driver. Instead, a GUID is read > from a header for each endpoint. The GUID identifies the device and is to > be used with an XML, provided by the vendor, to discover the available set > of metrics and their register mapping. This allows firmware updates to > modify the register space without needing to update the driver every time > with new mappings. Firmware writes a new GUID in this case to specify the > new mapping. Software tools with access to the associated XML file can > then interpret the changes. Is old hardware going to support this in the future? (I have in mind Apollo Lake / Broxton) > This module manages access to all PMT Telemetry endpoints on a system, > regardless of the device exporting them. It creates an intel_pmt_telem Name is not the best we can come up with. Would anyone else use PMT? Would it be vendor-agnostic ABI? (For example, I know that MIPI standardizes tracing protocols, like STM, do we have any plans to standardize this one?) telem -> telemetry. > class to manage the list. For each endpoint, sysfs files provide GUID and > size information as well as a pointer to the parent device the telemetry > comes from. Software may discover the association between endpoints and > devices by iterating through the list in sysfs, or by looking for the > existence of the class folder under the device of interest. A device node > of the same name allows software to then map the telemetry space for direct > access. ... > + tristate "Intel PMT telemetry driver" I think user should understand what is it from the title (hint: spell PMT fully). ... > obj-$(CONFIG_PMC_ATOM) += pmc_atom.o > +obj-$(CONFIG_INTEL_PMT_TELEM) += intel_pmt_telem.o Keep this and Kconfig section in order with the other stuff. ... bits.h? > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include ... > +/* platform device name to bind to driver */ > +#define TELEM_DRV_NAME "pmt_telemetry" Shouldn't be part of MFD header? ... > +#define TELEM_TBIR_MASK 0x7 GENMASK() ? > +struct pmt_telem_priv { > + struct device *dev; > + struct intel_dvsec_header *dvsec; > + struct telem_header header; > + unsigned long base_addr; > + void __iomem *disc_table; > + struct cdev cdev; > + dev_t devt; > + int devid; > +}; ... > + unsigned long phys = priv->base_addr; > + unsigned long pfn = PFN_DOWN(phys); > + unsigned long psize; > + > + psize = (PFN_UP(priv->base_addr + priv->header.size) - pfn) * PAGE_SIZE; > + if (vsize > psize) { > + dev_err(priv->dev, "Requested mmap size is too large\n"); > + return -EINVAL; > + } ... > +static ssize_t guid_show(struct device *dev, struct device_attribute *attr, > + char *buf) > +{ > + struct pmt_telem_priv *priv = dev_get_drvdata(dev); > + > + return sprintf(buf, "0x%x\n", priv->header.guid); > +} So, it's not a GUID but rather some custom number? Can we actually do a real GUID / UUID here? Because of TODO below I suppose it's not carved in stone (yet) and basically a protocol defined by firmware (which can be amended). ... > + /* TODO: replace with device properties??? */ So, please, fulfill. swnode I guess is what you are looking for. > + priv->dvsec = dev_get_platdata(&pdev->dev); > + if (!priv->dvsec) { > + dev_err(&pdev->dev, "Platform data not found\n"); > + return -ENODEV; > + } ... > + /* Local access and BARID only for now */ > + switch (priv->header.access_type) { > + case TELEM_ACCESS_LOCAL: > + if (priv->header.tbir) { > + dev_err(&pdev->dev, > + "Unsupported BAR index %d for access type %d\n", > + priv->header.tbir, priv->header.access_type); > + return -EINVAL; > + } > + fallthrough; What's the point? > + > + case TELEM_ACCESS_BARID: > + break; > + default: > + dev_err(&pdev->dev, "Unsupported access type %d\n", > + priv->header.access_type); > + return -EINVAL; > + } > + err = alloc_chrdev_region(&priv->devt, 0, 1, TELEM_DRV_NAME); err or ret? Be consistent in the module. > + if (err < 0) { ' < 0' Do we need it? > + dev_err(&pdev->dev, > + "PMT telemetry chrdev_region err: %d\n", err); > + return err; > + } ... > + err = pmt_telem_create_dev(priv); > + if (err < 0) ' < 0' Do we need it? > + goto fail_create_dev; > + > + return 0; > +} ... > +static const struct platform_device_id pmt_telem_table[] = { > + { > + .name = "pmt_telemetry", > + }, { > + /* sentinel */ > + } { .name = ... }, {} is enough. > +}; ... > +static int __init pmt_telem_init(void) > +{ > + int ret = class_register(&pmt_telem_class); > + > + if (ret) int ret; ret = ... if (ret) > + return ret; > + > + ret = platform_driver_register(&pmt_telem_driver); > + if (ret) > + class_unregister(&pmt_telem_class); > + > + return ret; > +} ... > +{ > +} > + Extra blank line. > +module_init(pmt_telem_init); > +module_exit(pmt_telem_exit); Better to attach to the respective functions. ... > +#include There is no user of this below, but types.h has users here. > +/* Telemetry types */ > +#define PMT_TELEM_TELEMETRY 0 > +#define PMT_TELEM_CRASHLOG 1 > + > +struct telem_header { > + u8 access_type; If it's part of hardware communication, shouldn't be rather __uXX types to show that this is part of protocol between software and hardware? > + u8 telem_type; > + u16 size; > + u32 guid; > + u32 base_offset; > + u8 tbir; > +}; -- With Best Regards, Andy Shevchenko