From patchwork Mon Apr 15 16:04:19 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Suzuki K Poulose X-Patchwork-Id: 162218 Delivered-To: patch@linaro.org Received: by 2002:a02:c6d8:0:0:0:0:0 with SMTP id r24csp3106192jan; Mon, 15 Apr 2019 09:06:52 -0700 (PDT) X-Google-Smtp-Source: APXvYqxZYKs0IFwzl5dT/2UpnY+TTFTf0oL6AjEpn97IqS4c5UPNCpJLV476Ta3H9seMYd19di1i X-Received: by 2002:a62:6e05:: with SMTP id j5mr74029867pfc.5.1555344412082; Mon, 15 Apr 2019 09:06:52 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1555344412; cv=none; d=google.com; s=arc-20160816; b=L9ks2IaQWY0HvECt3qJyIxMGFGLgsrRdrdEVHIITjXw5ICJA1wgj790kswEB4uEdjl ps7ntKE+zhF/zVLvGWXX+M9ghHDdnjJINnxTKCQDRwkdJ4lq5nv39rCqM+uK8Wqo5KDE rRV/+2TTRgju2LpoURLZJ74kJO8tt5FmXUSGYF5DKwg0O2Zkd34nO7Qjq2fiFZVX0KCa ofLSRy976wCkifWqcG/IvXdA9xeEOSjiwBytaenAyMKUSQ63ODh8XZ22+eXauqQKNqde F8l8RU6IUOhGkniHF7XbeujzIEDWpWUMEADSOJdqFiWo6c+D28igUrS4fGuCk9O3P9Mh kYGw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:references:in-reply-to:message-id:date :subject:cc:to:from; bh=7guntLSdYHrxwDXiY7Iwh3IBB++GOO9lgopk8y+dqWY=; b=i+0N3vlrniScww1ozbMg1yrnEa1ynBpLMICriSNXzikp/5eWwhIwNnba3pfTiMSVPb 4DfYe/frhBaQFfHCoocZA07KXryIyuObCr5HsQIghr3/QyVajE0IEs8u8TllV1Mhx8u/ 1GIYT6azzeaImJg8Fy0IzVWobh/S9iaiC/z7C+V5NhwqLozic2zntBCA18IxvcVQOXbT cDerrUFE6v21yMRxnanbLnKghR3tB1V4q8m4QwaWN4UueZCmVSGMZpBWY0ASkUX9dtvm 1NrPEqwVcZMRAeivImYC/MRyTPq1sH/hmFSvdMTfL8Abw4ZbfH/J94H5BTYdp62Pprgw 0J0w== ARC-Authentication-Results: i=1; mx.google.com; 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 k8si37245465plt.354.2019.04.15.09.06.51; Mon, 15 Apr 2019 09:06:52 -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; 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 S1728156AbfDOQGu (ORCPT + 30 others); Mon, 15 Apr 2019 12:06:50 -0400 Received: from foss.arm.com ([217.140.101.70]:38114 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728144AbfDOQGs (ORCPT ); Mon, 15 Apr 2019 12:06:48 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 3D64F80D; Mon, 15 Apr 2019 09:06:48 -0700 (PDT) Received: from en101.cambridge.arm.com (en101.cambridge.arm.com [10.1.196.93]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id B54793F68F; Mon, 15 Apr 2019 09:06:46 -0700 (PDT) From: Suzuki K Poulose To: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org, coresight@lists.linaro.org, mathieu.poirier@linaro.org, mike.leach@linaro.org, rjw@rjwysocki.net, robert.walker@arm.com, Suzuki K Poulose Subject: [PATCH v2 36/36] [RFC] coresight: Expose device connections via sysfs Date: Mon, 15 Apr 2019 17:04:19 +0100 Message-Id: <1555344260-12375-37-git-send-email-suzuki.poulose@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1555344260-12375-1-git-send-email-suzuki.poulose@arm.com> References: <1555344260-12375-1-git-send-email-suzuki.poulose@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Coresight device connections are a bit complicated and is not exposed currently to the user. One has to look at the platform descriptions (DT bindings or ACPI bindings) to make an understanding. Given the new naming scheme, it will be helpful to have this information to choose the appropriate devices for tracing. This patch exposes the device connections via links in the sysfs directories. e.g, for a connection devA[OutputPort_X] -> devB[InputPort_Y] is represented as two symlinks: /sys/bus/coresight/.../devA/out:X -> /sys/bus/coresight/.../devB /sys/bus/coresight/.../devB/in:Y -> /sys/bus/coresight/.../devA We could have segregated the links to separate directories aka attribute_groups, for input_ports and output_ports. But the sysfs won't let you create empty attribute_groups and thus it becomes complicated to dynamically create the attribute_groups. Cc: Mathieu Poirier Signed-off-by: Suzuki K Poulose --- drivers/hwtracing/coresight/coresight.c | 120 +++++++++++++++++++++++++++++--- include/linux/coresight.h | 4 ++ 2 files changed, 113 insertions(+), 11 deletions(-) -- 2.7.4 diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c index 4d63063..50a1f29 100644 --- a/drivers/hwtracing/coresight/coresight.c +++ b/drivers/hwtracing/coresight/coresight.c @@ -981,9 +981,92 @@ static void coresight_device_release(struct device *dev) kfree(csdev); } + +/* + * coresight_make_links: Make a link for a connection from a @orig + * device to @target, represented by @conn. + * + * e.g, for devOrig[output_X] -> devTarget[input_Y] is represented + * as two symbolic links : + * + * /sys/.../devOrig/out:X -> /sys/.../devTarget/ + * /sys/.../devTarget/in:Y -> /sys/.../devOrig/ + * + * The link names are allocated for a device where it appears. i.e, the + * "out" link on the master and "in" link on the slave device. + * The link names are stored in the connection record for avoiding + * the reconstruction of names for removal. + */ +static int coresight_make_links(struct coresight_device *orig, + struct coresight_connection *conn, + struct coresight_device *target) +{ + int ret = -ENOMEM; + char *outs = NULL, *ins = NULL; + + do { + outs = devm_kasprintf(&orig->dev, GFP_KERNEL, + "out:%d", conn->outport); + if (!outs) + break; + ins = devm_kasprintf(&target->dev, GFP_KERNEL, + "in:%d", conn->child_port); + if (!ins) + break; + ret = sysfs_create_link(&orig->dev.kobj, + &target->dev.kobj, outs); + if (ret) + break; + + ret = sysfs_create_link(&target->dev.kobj, + &orig->dev.kobj, ins); + if (ret) { + sysfs_remove_link(&orig->dev.kobj, outs); + break; + } + + conn->inlink_name = ins; + conn->outlink_name = outs; + /* + * Install the device connection. This also indicates that + * the links are operational on both ends. + */ + conn->child_dev = target; + return 0; + } while (0); + + if (outs) + devm_kfree(&orig->dev, outs); + if (ins) + devm_kfree(&target->dev, ins); + return ret; +} + +/* + * coresight_remove_links: Remove the sysfs links for a given connection @conn, + * from @orig device to @target device. See coresight_make_links() for more + * details. + */ +static void coresight_remove_links(struct coresight_device *orig, + struct coresight_connection *conn) +{ + struct coresight_device *target = conn->child_dev; + + if (!orig || !target) + return; + + sysfs_remove_link(&orig->dev.kobj, conn->outlink_name); + sysfs_remove_link(&target->dev.kobj, conn->inlink_name); + + devm_kfree(&target->dev, conn->inlink_name); + devm_kfree(&orig->dev, conn->outlink_name); + conn->inlink_name = conn->outlink_name = NULL; + conn->child_dev = NULL; +} + static int coresight_orphan_match(struct device *dev, void *data) { - int i; + int i, ret = 0; bool still_orphan = false; struct coresight_device *csdev, *i_csdev; struct coresight_connection *conn; @@ -1008,19 +1091,23 @@ static int coresight_orphan_match(struct device *dev, void *data) /* We have found at least one orphan connection */ if (conn->child_dev == NULL) { /* Does it match this newly added device? */ - if (conn->child_fwnode == csdev->dev.fwnode) - conn->child_dev = csdev; - else + if (conn->child_fwnode == csdev->dev.fwnode) { + ret = coresight_make_links(i_csdev, + conn, csdev); + if (ret) + return ret; + } else { /* This component still has an orphan */ still_orphan = true; + } } } i_csdev->orphan = still_orphan; /* - * Returning '0' ensures that all known component on the - * bus will be checked. + * Returning '0' in case we didn't encounter any error, + * ensures that all known component on the bus will be checked. */ return 0; } @@ -1038,7 +1125,7 @@ static int coresight_fixup_orphan_conns(struct coresight_device *csdev) static int coresight_fixup_device_conns(struct coresight_device *csdev) { - int i; + int i, ret = 0; for (i = 0; i < csdev->pdata->nr_outport; i++) { struct coresight_connection *conn = &csdev->pdata->conns[i]; @@ -1048,9 +1135,12 @@ static int coresight_fixup_device_conns(struct coresight_device *csdev) (void *)conn->child_fwnode, device_fwnode_match); if (dev) { - conn->child_dev = to_coresight_device(dev); + ret = coresight_make_links(csdev, conn, + to_coresight_device(dev)); /* and put reference from 'bus_find_device()' */ put_device(dev); + if (ret) + break; } else { csdev->orphan = true; conn->child_dev = NULL; @@ -1085,7 +1175,7 @@ static int coresight_remove_match(struct device *dev, void *data) if (csdev->dev.fwnode == conn->child_fwnode) { iterator->orphan = true; - conn->child_dev = NULL; + coresight_remove_links(iterator, conn); /* * Drop the reference to the handle for the remote * device acquired in parsing the connections from @@ -1179,10 +1269,18 @@ void coresight_release_platform_data(struct coresight_device *csdev, struct coresight_platform_data *pdata) { int i; + struct coresight_connection *conns = pdata->conns; for (i = 0; i < pdata->nr_outport; i++) { - if (pdata->conns[i].child_fwnode) { - fwnode_handle_put(pdata->conns[i].child_fwnode); + /* If we have made the links, remove them now */ + if (csdev && conns[i].child_dev) + coresight_remove_links(csdev, &conns[i]); + /* + * Drop the refcount and clear the handle as this device + * is going away + */ + if (conns[i].child_fwnode) { + fwnode_handle_put(conns[i].child_fwnode); pdata->conns[i].child_fwnode = 0; } } diff --git a/include/linux/coresight.h b/include/linux/coresight.h index d6367a0..284d783 100644 --- a/include/linux/coresight.h +++ b/include/linux/coresight.h @@ -130,12 +130,16 @@ struct coresight_desc { * @chid_fwnode: remote component's fwnode handle. * @child_dev: a @coresight_device representation of the component connected to @outport. + * @inlink_name: Name for the "input" link + * @outlink_name: Name for the "output" link */ struct coresight_connection { int outport; int child_port; struct fwnode_handle *child_fwnode; struct coresight_device *child_dev; + const char *inlink_name; + const char *outlink_name; }; /**