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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 52A53C30654 for ; Mon, 3 Jul 2023 19:57:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231304AbjGCT5g (ORCPT ); Mon, 3 Jul 2023 15:57:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56318 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230083AbjGCT5e (ORCPT ); Mon, 3 Jul 2023 15:57:34 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 750A5E69; Mon, 3 Jul 2023 12:57:33 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 09A7860FE8; Mon, 3 Jul 2023 19:57:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EED19C433C7; Mon, 3 Jul 2023 19:57:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1688414252; bh=H9G0JTedWKE7c+iMv9ZhpL/buzoVhwoHAXTZNZuXBB0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=KT7/VON5HxLKRyET1XLEKgYCRtkQG0BQDJHzgLJtd9WMG3xTnmWOQaNWFNu4GRA9R yD4sQtNKP4NeqbiU0pNhFlxYFlPM3K/NgbER4NlnKIxr9f6iZmZp+cdpmZ1IpFuvsY eaM9sQjw9z3qz9idYYkjx+Kl66tdj/8wXlqFg1g4= Date: Mon, 3 Jul 2023 21:57:29 +0200 From: Greg KH To: Umang Jain Cc: linux-staging@lists.linux.dev, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, stefan.wahren@i2se.com, f.fainelli@gmail.com, athierry@redhat.com, error27@gmail.com, dave.stevenson@raspberrypi.com, kieran.bingham@ideasonboard.com, laurent.pinchart@ideasonboard.com Subject: Re: [PATCH v8 1/5] staging: vc04_services: vchiq_arm: Add new bus type and device type Message-ID: <2023070301-elective-devious-2204@gregkh> References: <20230627201628.207483-1-umang.jain@ideasonboard.com> <20230627201628.207483-2-umang.jain@ideasonboard.com> <2023070302-gallon-unison-2b9c@gregkh> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 03, 2023 at 06:15:25PM +0200, Umang Jain wrote: > Hi Greg, > > (resending because it got bounced off a few lists due a line a copied with > HTML tag..) > > On 7/3/23 3:28 PM, Greg KH wrote: > > On Tue, Jun 27, 2023 at 10:16:24PM +0200, Umang Jain wrote: > > > The devices that the vchiq interface registers (bcm2835-audio, > > > bcm2835-camera) are implemented and exposed by the VC04 firmware. > > > The device tree describes the VC04 itself with the resources required > > > to communicate with it through a mailbox interface. However, the > > > vchiq interface registers these devices as platform devices. This > > > also means the specific drivers for these devices are getting > > > registered as platform drivers. This is not correct and a blatant > > > abuse of platform device/driver. > > > > > > Add a new bus type, vchiq_bus_type and device type (struct vchiq_device) > > > which will be used to migrate child devices that the vchiq interfaces > > > creates/registers from the platform device/driver. > > > > > > Signed-off-by: Umang Jain > > > --- > > > drivers/staging/vc04_services/Makefile | 1 + > > > .../interface/vchiq_arm/vchiq_device.c | 78 +++++++++++++++++++ > > > .../interface/vchiq_arm/vchiq_device.h | 43 ++++++++++ > > > 3 files changed, 122 insertions(+) > > > create mode 100644 drivers/staging/vc04_services/interface/vchiq_arm/vchiq_device.c > > > create mode 100644 drivers/staging/vc04_services/interface/vchiq_arm/vchiq_device.h > > > > > > diff --git a/drivers/staging/vc04_services/Makefile b/drivers/staging/vc04_services/Makefile > > > index 44794bdf6173..2d071e55e175 100644 > > > --- a/drivers/staging/vc04_services/Makefile > > > +++ b/drivers/staging/vc04_services/Makefile > > > @@ -5,6 +5,7 @@ vchiq-objs := \ > > > interface/vchiq_arm/vchiq_core.o \ > > > interface/vchiq_arm/vchiq_arm.o \ > > > interface/vchiq_arm/vchiq_debugfs.o \ > > > + interface/vchiq_arm/vchiq_device.o \ > > > interface/vchiq_arm/vchiq_connected.o \ > > > ifdef CONFIG_VCHIQ_CDEV > > > diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_device.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_device.c > > > new file mode 100644 > > > index 000000000000..dff312e9735c > > > --- /dev/null > > > +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_device.c > > > @@ -0,0 +1,78 @@ > > > +// SPDX-License-Identifier: GPL-2.0 > > > +/* > > > + * vchiq_device.c - VCHIQ generic device and bus-type > > > + * > > > + * Copyright (c) 2023 Ideas On Board Oy > > > + */ > > > + > > > +#include > > > +#include > > > +#include > > > + > > > +#include "vchiq_device.h" > > > + > > > +static int vchiq_bus_type_match(struct device *dev, struct device_driver *drv); > > > + > > > +struct bus_type vchiq_bus_type = { > > > + .name = "vchiq-bus", > > > + .match = vchiq_bus_type_match, > > > +}; > > > + > > > +static int vchiq_bus_type_match(struct device *dev, struct device_driver *drv) > > > +{ > > > + if (dev->bus == &vchiq_bus_type && > > > + strcmp(dev_name(dev), drv->name) == 0) > > > + return 1; > > > + return 0; > > > +} > > > + > > > +static void vchiq_device_release(struct device *dev) > > > +{ > > > + struct vchiq_device *device; > > > + > > > + device = container_of(dev, struct vchiq_device, dev); > > > + kfree(device); > > > +} > > > + > > > +int vchiq_device_register(struct device *parent, const char *name) > > > +{ > > > + struct vchiq_device *device = NULL; > > No need to set this to NULL. > > > > > + int ret; > > > + > > > + device = kzalloc(sizeof(*device), GFP_KERNEL); > > > + if (!device) > > > + return -ENOMEM; > > > + > > > + device->dev.init_name = name; > > > + device->dev.parent = parent; > > > + device->dev.bus = &vchiq_bus_type; > > > + device->dev.release = vchiq_device_release; > > > + > > > + ret = device_register(&device->dev); > > > + if (ret) { > > > + put_device(&device->dev); > > > + return -EINVAL; > > Why not return the error given to you? > > > > > + } > > > + > > > + return 0; > > You create a new device, shouldn't you return it? How is it going to be > > looked up again? > > So I haven't come across usage of the device other than unregistered right > now. If you look at the platform_device static instances of bcm2835_camera, > bcm2835-audio, they are also just used for unregistering the devices only. That feels odd, you need to register a device, use it, and then unregister it when finished. Otherwise why have it? > So for unregistering devices on vchiq_bus - I am using the > >     bus_for_each_dev(&vchiq_bus_type, NULL, NULL, vchiq_device_unregister); Ick, no, that is horrid, unregister the device that was created, that's how all other busses work. > So basically I can return the instances right now, but there would be no > user of those instances. You should save it :) > > > > > +} > > > + > > > +int vchiq_device_unregister(struct device *dev, void *data) > > You should be passing in a sruct vchiq_device *device here, right? > > > > And why the void pointer you do nothing with? > > ack > > > > > > > +{ > > > + device_unregister(dev); > > > + return 0; > > > +} > > No need to export this? > > In the previous reviews you mentioned not to export it. The vchiq_bus_type > is internal to the vchiq_driver to register it's child devices. I don't > think any other module will be using this bus directly? Maybe I'm mistaken? Ok, just didn't match up with the register function export. thanks, greg k-h