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=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 E73ADC11D2F for ; Mon, 24 Feb 2020 16:37:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B981020836 for ; Mon, 24 Feb 2020 16:37:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582562233; bh=EaF2MyjS2zZaaolBzvb8Q1sCIgrqXN34CG6/GRVu+iw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=X469/H+GXhZnvaq0KC4iXNucDsm5mEfC2Q7A3uZFGlkxjyN1w9R/ax8Bvh4UZp+ld nLh+KQned0ZFjIwK7X0x3SO5WEmfKLDJb5+kBl6ZHvpoUAj5MIm1BT5D6CXjamOWS9 yTRoZk+75DdGYaA40PyjuFfsDlCFYur3ZNWCx2t4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727438AbgBXQhN (ORCPT ); Mon, 24 Feb 2020 11:37:13 -0500 Received: from mail.kernel.org ([198.145.29.99]:41986 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727160AbgBXQhN (ORCPT ); Mon, 24 Feb 2020 11:37:13 -0500 Received: from localhost (unknown [122.182.199.233]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 009AA20637; Mon, 24 Feb 2020 16:37:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582562232; bh=EaF2MyjS2zZaaolBzvb8Q1sCIgrqXN34CG6/GRVu+iw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=tPm95vGIpi/ZtZoLMfrUCE5SZ1PDT8Cqi/ELFlvHsA0J9xzr54BhKa5RXGOBckvjD OEqlGIjTd8HOAwSrcTqxPCRsYsGZiQY0h4/c84ANrlzg9t/pFgFAtnM4nv/xrdDYV2 lhOTZmDtPZ50QYXLS/9CWV4vnFKRBxEVBXYuBZSk= Date: Mon, 24 Feb 2020 22:07:07 +0530 From: Vinod Koul To: Peter Ujfalusi Cc: dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, dan.j.williams@intel.com, geert@linux-m68k.org Subject: Re: [PATCH v3] dmaengine: Add basic debugfs support Message-ID: <20200224163707.GA2618@vkoul-mobl> References: <20200205111557.24125-1-peter.ujfalusi@ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200205111557.24125-1-peter.ujfalusi@ti.com> Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org On 05-02-20, 13:15, Peter Ujfalusi wrote: > Via the /sys/kernel/debug/dmaengine users can get information about the > DMA devices and the used channels. > > Example output on am654-evm with audio using two channels and after running > dmatest on 6 channels: > > # cat /sys/kernel/debug/dmaengine > dma0 (285c0000.dma-controller): number of channels: 96 > > dma1 (31150000.dma-controller): number of channels: 267 > dma1chan0 | 2b00000.mcasp:tx > dma1chan1 | 2b00000.mcasp:rx > dma1chan2 | in-use > dma1chan3 | in-use > dma1chan4 | in-use > dma1chan5 | in-use > dma1chan6 | in-use > dma1chan7 | in-use > > For slave channels we can show the device and the channel name a given > channel is requested. > For non slave devices the only information we know is that the channel is > in use. > > DMA drivers can implement the optional dbg_show callback to provide > controller specific information instead of the generic one. > > It is easy to extend the generic dmaengine_dbg_show() to print additional > information about the used channels. > > I have taken the idea from gpiolib. > > Signed-off-by: Peter Ujfalusi > --- > Hi, > > Changes since v2: > - Use dma_chan_name() for printing the channel's name > > Changes since v1: > - Use much more simplified fops for the debugfs file (via DEFINE_SHOW_ATTRIBUTE) > - do not allow modification to dma_device_list while the debugfs file is read > - rename the slave_name to dbg_client_name (it is only for debugging) > - print information about dma_router if it is used by the channel > - Formating of the output slightly changed > > Regards, > Peter > > drivers/dma/dmaengine.c | 65 +++++++++++++++++++++++++++++++++++++++ > include/linux/dmaengine.h | 12 +++++++- > 2 files changed, 76 insertions(+), 1 deletion(-) > > diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c > index c3b1283b6d31..37c3a4cd5b1a 100644 > --- a/drivers/dma/dmaengine.c > +++ b/drivers/dma/dmaengine.c > @@ -32,6 +32,7 @@ > #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt > > #include > +#include > #include > #include > #include > @@ -760,6 +761,11 @@ struct dma_chan *dma_request_chan(struct device *dev, const char *name) > return chan ? chan : ERR_PTR(-EPROBE_DEFER); > > found: > +#ifdef CONFIG_DEBUG_FS > + chan->dbg_client_name = kasprintf(GFP_KERNEL, "%s:%s", dev_name(dev), > + name); > +#endif > + > chan->name = kasprintf(GFP_KERNEL, "dma:%s", name); > if (!chan->name) > return chan; > @@ -837,6 +843,11 @@ void dma_release_channel(struct dma_chan *chan) > chan->name = NULL; > chan->slave = NULL; > } > + > +#ifdef CONFIG_DEBUG_FS > + kfree(chan->dbg_client_name); > + chan->dbg_client_name = NULL; > +#endif > mutex_unlock(&dma_list_mutex); > } > EXPORT_SYMBOL_GPL(dma_release_channel); > @@ -1562,3 +1573,57 @@ static int __init dma_bus_init(void) > return class_register(&dma_devclass); > } > arch_initcall(dma_bus_init); > + > +#ifdef CONFIG_DEBUG_FS > +static void dmaengine_dbg_show(struct seq_file *s, struct dma_device *dma_dev) > +{ > + struct dma_chan *chan; > + > + list_for_each_entry(chan, &dma_dev->channels, device_node) { > + if (chan->client_count) { > + seq_printf(s, " %-13s| %s", dma_chan_name(chan), > + chan->dbg_client_name ?: "in-use"); > + > + if (chan->router) > + seq_printf(s, " (via router: %s)\n", > + dev_name(chan->router->dev)); > + else > + seq_puts(s, "\n"); > + } > + } > +} > + > +static int dmaengine_debugfs_show(struct seq_file *s, void *data) > +{ > + struct dma_device *dma_dev = NULL; > + > + mutex_lock(&dma_list_mutex); > + list_for_each_entry(dma_dev, &dma_device_list, global_node) { > + seq_printf(s, "dma%d (%s): number of channels: %u\n", > + dma_dev->dev_id, dev_name(dma_dev->dev), > + dma_dev->chancnt); > + > + if (dma_dev->dbg_show) > + dma_dev->dbg_show(s, dma_dev); do we really want a custom dbg_show()..? Drivers can add their own files... > + else > + dmaengine_dbg_show(s, dma_dev); > + > + if (!list_is_last(&dma_dev->global_node, &dma_device_list)) > + seq_puts(s, "\n"); > + } > + mutex_unlock(&dma_list_mutex); > + > + return 0; > +} > +DEFINE_SHOW_ATTRIBUTE(dmaengine_debugfs); > + > +static int __init dmaengine_debugfs_init(void) > +{ > + /* /sys/kernel/debug/dmaengine */ > + debugfs_create_file("dmaengine", 0444, NULL, NULL, > + &dmaengine_debugfs_fops); Should we add a directory? That way we can keep adding stuff into that one -- ~Vinod