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=-6.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,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 8AA41C35E01 for ; Tue, 25 Feb 2020 15:46:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 48CE720CC7 for ; Tue, 25 Feb 2020 15:46:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="Jk61CNmR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730593AbgBYPqS (ORCPT ); Tue, 25 Feb 2020 10:46:18 -0500 Received: from mail-qt1-f194.google.com ([209.85.160.194]:40475 "EHLO mail-qt1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726019AbgBYPqR (ORCPT ); Tue, 25 Feb 2020 10:46:17 -0500 Received: by mail-qt1-f194.google.com with SMTP id v25so9332157qto.7 for ; Tue, 25 Feb 2020 07:46:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=pEZQcw9jdNIyRgx/1d69GLN8AZtR3YeLDjX3xwRN5v8=; b=Jk61CNmRNH5Kha3jhrzAU0P58lel7zVctZX2F7REsCyLbmvaQUt9cdT7U+pC+5TqEH oYtG2dKKSTg35seSELRRMJApCz/OXUXoyVmwPYtv6LxVW42yvNCsL6zsoIuc9W3GwFgM sVL6Y4e5VhnWGjNVCaCVJC935ClkkxYjKIqWCnztPmShZPPyVSXBiP+W6KFP7oaEzaeq g1EkmFieMNBaegO/OFwQbWwt7EhuByKJIp38V7YrIl6Y1Pj/145dtjj64qhYXvRX52W3 floyi7euG6khGcc4uavJ7ZP7cMJ85EngiEDNoxIQqD7ErvSXSllCbGlCRp1atFS0EGse sw/w== 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=pEZQcw9jdNIyRgx/1d69GLN8AZtR3YeLDjX3xwRN5v8=; b=A6UysY3nclO00h1GA2eZLOwItKZnQ2mNXTPtEZW49suAvclAswkm2O15yZST75HnW9 3hGiJ2VoHa1zc1uInvgmWKnY3V+ussbbJrqqIwjmv29chY/f5FCd0w9D5pU75XvuWT/2 c5z+lzx+idnW5H6k3JNdW2RYzszRAWR72EYbrHIIK8IhIqZARGMVdDvlU+NVLNvqd4qw Tlyk15YKbO67ufq8TItbvdGJivC0/EPyQlQzZQ76Fm8vT1XJHnmn4DWzrxKLcFvfi8hA eUrQjMBnpodxdGQUQOqpWnaupqyWIokvCeheJSYdb1yK+7Esn341jyRcpKTWbvAFdq1S coHg== X-Gm-Message-State: APjAAAVrrROHXHpS1brYHpEhZEKdoEKyPU7U1ZBiNActmciOh3Tq0kyw 3vYQc3whAafiCdYAvmppe8R07xEzdE/ucp+yqES31Q== X-Google-Smtp-Source: APXvYqwskw9OUL/xghhvwhI8dXAtgFXnH/a+xM+hdpazpgY7TQPiHlVt4Ge6Se+PvVclU58I2qq0Dqc3nrazrmdXAaw= X-Received: by 2002:ac8:405a:: with SMTP id j26mr55090188qtl.88.1582645575991; Tue, 25 Feb 2020 07:46:15 -0800 (PST) MIME-Version: 1.0 References: <20200211105808.27884-1-mike.leach@linaro.org> <20200211105808.27884-4-mike.leach@linaro.org> <20200214231706.GD20024@xps15> In-Reply-To: <20200214231706.GD20024@xps15> From: Mike Leach Date: Tue, 25 Feb 2020 15:46:04 +0000 Message-ID: Subject: Re: [PATCH v4 3/6] coresight: Add generic sysfs link creation functions. To: Mathieu Poirier Cc: linux-arm-kernel , Coresight ML , "open list:DOCUMENTATION" , "Suzuki K. Poulose" Content-Type: text/plain; charset="UTF-8" Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org Hi Mathieu, On Fri, 14 Feb 2020 at 23:17, Mathieu Poirier wrote: > > On Tue, Feb 11, 2020 at 10:58:05AM +0000, Mike Leach wrote: > > To allow the connections between coresight components to be represented > > in sysfs, generic methods for creating sysfs links between two coresight > > devices are added. > > > > Signed-off-by: Mike Leach > > Reviewed-by: Suzuki K Poulose > > --- > > drivers/hwtracing/coresight/Makefile | 3 +- > > drivers/hwtracing/coresight/coresight-priv.h | 4 + > > drivers/hwtracing/coresight/coresight-sysfs.c | 124 ++++++++++++++++++ > > include/linux/coresight.h | 20 +++ > > 4 files changed, 150 insertions(+), 1 deletion(-) > > create mode 100644 drivers/hwtracing/coresight/coresight-sysfs.c > > > > diff --git a/drivers/hwtracing/coresight/Makefile b/drivers/hwtracing/coresight/Makefile > > index 0e3e72f0f510..19497d1d92bf 100644 > > --- a/drivers/hwtracing/coresight/Makefile > > +++ b/drivers/hwtracing/coresight/Makefile > > @@ -2,7 +2,8 @@ > > # > > # Makefile for CoreSight drivers. > > # > > -obj-$(CONFIG_CORESIGHT) += coresight.o coresight-etm-perf.o coresight-platform.o > > +obj-$(CONFIG_CORESIGHT) += coresight.o coresight-etm-perf.o \ > > + coresight-platform.o coresight-sysfs.o > > obj-$(CONFIG_CORESIGHT_LINK_AND_SINK_TMC) += coresight-tmc.o \ > > coresight-tmc-etf.o \ > > coresight-tmc-etr.o > > diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h > > index 1cad642f27aa..a4a658d46045 100644 > > --- a/drivers/hwtracing/coresight/coresight-priv.h > > +++ b/drivers/hwtracing/coresight/coresight-priv.h > > @@ -153,6 +153,10 @@ struct coresight_device *coresight_get_sink_by_id(u32 id); > > struct list_head *coresight_build_path(struct coresight_device *csdev, > > struct coresight_device *sink); > > void coresight_release_path(struct list_head *path); > > +int coresight_add_sysfs_link(struct coresight_sysfs_link *info); > > +void coresight_remove_sysfs_link(struct coresight_sysfs_link *info); > > +int coresight_create_conns_sysfs_group(struct coresight_device *csdev); > > +void coresight_remove_conns_sysfs_group(struct coresight_device *csdev); > > > > #ifdef CONFIG_CORESIGHT_SOURCE_ETM3X > > extern int etm_readl_cp14(u32 off, unsigned int *val); > > diff --git a/drivers/hwtracing/coresight/coresight-sysfs.c b/drivers/hwtracing/coresight/coresight-sysfs.c > > new file mode 100644 > > index 000000000000..17d565941e5e > > --- /dev/null > > +++ b/drivers/hwtracing/coresight/coresight-sysfs.c > > @@ -0,0 +1,124 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > +/* > > + * Copyright (c) 2019, Linaro Limited, All rights reserved. > > + * Author: Mike Leach > > + */ > > + > > +#include > > +#include > > + > > +#include "coresight-priv.h" > > + > > +/* > > + * Connections group - links attribute. > > + * Count of created links between coresight components in the group. > > + */ > > +static ssize_t nr_links_show(struct device *dev, > > + struct device_attribute *attr, > > + char *buf) > > +{ > > + struct coresight_device *csdev = to_coresight_device(dev); > > + > > + return scnprintf(buf, PAGE_SIZE, "%d\n", csdev->nr_links); > > +} > > +static DEVICE_ATTR_RO(nr_links); > > + > > +static struct attribute *coresight_conns_attrs[] = { > > + &dev_attr_nr_links.attr, > > + NULL, > > +}; > > + > > +static struct attribute_group coresight_conns_group = { > > + .attrs = coresight_conns_attrs, > > + .name = "connections", > > +}; > > + > > +/* > > + * Create connections group for CoreSight devices. > > + * This group will then be used to collate the sysfs links between > > + * devices. > > + */ > > +int coresight_create_conns_sysfs_group(struct coresight_device *csdev) > > +{ > > + int ret = 0; > > + > > + if (!csdev) > > + return -EINVAL; > > + > > + ret = sysfs_create_group(&csdev->dev.kobj, &coresight_conns_group); > > + if (ret) > > + return ret; > > + > > + csdev->has_conns_grp = true; > > The only place coresight_create_conns_sysfs_group() is used is in > coresight_register() where an error is returned to driver probe() functions if > an error occurs. Have you found places where csdev->has_conns_grp is needed? > If not please remove. > There is a sequence of calls in coresight_register() which occur after the coresight_create_conns_sysfs_group() - any one of which may throw an error resulting in an immediate coresight_unregister() and hence coresight_release_platform_data() => coresight_remove_conns_sysfs_group(). There is also an alternate path through coresight_register() which also results in coresight_release_platform_data() occurring before we have created the group. The flag ensures that both paths clean up the sysfs connection data correctly and safely. Regards Mike > > + return ret; > > +} > > + > > +void coresight_remove_conns_sysfs_group(struct coresight_device *csdev) > > +{ > > + if (!csdev) > > + return; > > + > > + if (csdev->has_conns_grp) { > > + sysfs_remove_group(&csdev->dev.kobj, &coresight_conns_group); > > + csdev->has_conns_grp = false; > > + } > > +} > > + > > +int coresight_add_sysfs_link(struct coresight_sysfs_link *info) > > +{ > > + int ret = 0; > > + > > + if (!info) > > + return -EINVAL; > > + if (!info->orig || !info->target || > > + !info->orig_name || !info->target_name) > > + return -EINVAL; > > + if (!info->orig->has_conns_grp || !info->target->has_conns_grp) > > + return -EINVAL; > > + > > + /* first link orig->target */ > > + ret = sysfs_add_link_to_group(&info->orig->dev.kobj, > > + coresight_conns_group.name, > > + &info->target->dev.kobj, > > + info->orig_name); > > + if (ret) > > + return ret; > > + > > + /* second link target->orig */ > > + ret = sysfs_add_link_to_group(&info->target->dev.kobj, > > + coresight_conns_group.name, > > + &info->orig->dev.kobj, > > + info->target_name); > > + > > + /* error in second link - remove first - otherwise inc counts */ > > + if (ret) { > > + sysfs_remove_link_from_group(&info->orig->dev.kobj, > > + coresight_conns_group.name, > > + info->orig_name); > > + } else { > > + info->orig->nr_links++; > > + info->target->nr_links++; > > + } > > + > > + return ret; > > +} > > + > > +void coresight_remove_sysfs_link(struct coresight_sysfs_link *info) > > +{ > > + if (!info) > > + return; > > + if (!info->orig || !info->target || > > + !info->orig_name || !info->target_name) > > + return; > > + > > + sysfs_remove_link_from_group(&info->orig->dev.kobj, > > + coresight_conns_group.name, > > + info->orig_name); > > + > > + sysfs_remove_link_from_group(&info->target->dev.kobj, > > + coresight_conns_group.name, > > + info->target_name); > > + > > + info->orig->nr_links--; > > + info->target->nr_links--; > > +} > > diff --git a/include/linux/coresight.h b/include/linux/coresight.h > > index 193cc9dbf448..a2ec25e02ca9 100644 > > --- a/include/linux/coresight.h > > +++ b/include/linux/coresight.h > > @@ -148,6 +148,20 @@ struct coresight_connection { > > struct coresight_device *child_dev; > > }; > > > > +/** > > + * struct coresight_sysfs_link - representation of a connection in sysfs. > > + * @orig: Originating (master) coresight device for the link. > > + * @orig_name: Name to use for the link orig->target. > > + * @target: Target (slave) coresight device for the link. > > + * @target_name: Name to use for the link target->orig. > > + */ > > +struct coresight_sysfs_link { > > + struct coresight_device *orig; > > + const char *orig_name; > > + struct coresight_device *target; > > + const char *target_name; > > +}; > > + > > /** > > * struct coresight_device - representation of a device as used by the framework > > * @pdata: Platform data with device connections associated to this device. > > @@ -165,6 +179,9 @@ struct coresight_connection { > > * @ea: Device attribute for sink representation under PMU directory. > > * @ect_dev: Associated cross trigger device. Not part of the trace data > > * path or connections. > > + * @nr_links: number of sysfs links created to other components from this > > + * device. These will appear in the "connections" group. > > + * @has_conns_grp: Have added a "connections" group for sysfs links. > > */ > > struct coresight_device { > > struct coresight_platform_data *pdata; > > @@ -180,6 +197,9 @@ struct coresight_device { > > struct dev_ext_attribute *ea; > > /* cross trigger handling */ > > struct coresight_device *ect_dev; > > + /* sysfs links between components */ > > + int nr_links; > > + bool has_conns_grp; > > }; > > With the above: > > Reviewed-by: Mathieu Poirier > > > > > /* > > -- > > 2.17.1 > > -- Mike Leach Principal Engineer, ARM Ltd. Manchester Design Centre. UK