From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6864623A4 for ; Wed, 21 Dec 2022 11:15:07 +0000 (UTC) Received: from pendragon.ideasonboard.com (213-243-189-158.bb.dnainternet.fi [213.243.189.158]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 17D1BFB; Wed, 21 Dec 2022 12:15:04 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1671621304; bh=yveR9JIKb30hOShJCMWYbHM+OTy0mDpxYqQ6MAD0wM8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=g4NV3YicSsx56dEf3CRfEx2oD8ZVtpxrwM8Qvzjg0L1OEZsqKcjJyP6as+Zv6+8YC DJ7CAxa+7tog2sqUnc92yoXqWelxKN7UTaTY0pJGHWi7hAWVM5HNvL0IUKpvaCkRr8 +jGtdvbLc/yB2sNTIYpmK1dfjuwiVpTEl2d4gvP8= Date: Wed, 21 Dec 2022 13:14:59 +0200 From: Laurent Pinchart 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 , Greg Kroah-Hartman , Florian Fainelli , Adrien Thierry , Dan Carpenter , Nicolas Saenz Julienne , Phil Elwell , Dave Stevenson , Kieran Bingham Subject: Re: [PATCH] staging: vc04_services: vchiq_arm: Create platform_device per device Message-ID: References: <20221220084404.19280-1-umang.jain@ideasonboard.com> Precedence: bulk X-Mailing-List: linux-staging@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20221220084404.19280-1-umang.jain@ideasonboard.com> Hi Umang, Thank you for the patch. On Tue, Dec 20, 2022 at 02:14:04PM +0530, Umang Jain wrote: > Create a proper per device platorm_device structure for all the child > devices that needs to be registered by vchiq platform driver. Replace > the vchiq_register_child() with platform_add_devices() to register the > child devices. This explains what the patch does, but not why. > This is part of an effort to address TODO item "Get rid of all non > essential global structures and create a proper per device structure" And this explains part of the reason only. Could you please expand the commit message with the reasoning behind this change ? It's not clear from the change below why this is needed and good. > Signed-off-by: Umang Jain > --- > .../interface/vchiq_arm/vchiq_arm.c | 59 ++++++++++--------- > 1 file changed, 31 insertions(+), 28 deletions(-) > > diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c > index 22de23f3af02..fa42ea3791a7 100644 > --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c > +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c > @@ -65,8 +65,29 @@ int vchiq_susp_log_level = VCHIQ_LOG_ERROR; > DEFINE_SPINLOCK(msg_queue_spinlock); > struct vchiq_state g_state; > > -static struct platform_device *bcm2835_camera; > -static struct platform_device *bcm2835_audio; > +static u64 vchiq_device_dmamask = DMA_BIT_MASK(32); The fact that this isn't const and is used by two different platform_device instances is worrying. Either it can be made const, or it's wrong. > + > +static struct platform_device bcm2835_camera = { > + .name = "bcm2835-camera", > + .id = PLATFORM_DEVID_NONE, > + .dev = { > + .dma_mask = &vchiq_device_dmamask, > + } > +}; > + > +static struct platform_device bcm2835_audio = { > + .name = "bcm2835_audio", > + .id = PLATFORM_DEVID_NONE, > + .dev = { > + .dma_mask = &vchiq_device_dmamask, > + } > + Extra blank line. > +}; > + > +static struct platform_device *vchiq_devices[] __initdata = { Make it const. > + &bcm2835_camera, > + &bcm2835_audio, > +}; > > struct vchiq_drvdata { > const unsigned int cache_line_size; > @@ -1763,28 +1784,6 @@ static const struct of_device_id vchiq_of_match[] = { > }; > MODULE_DEVICE_TABLE(of, vchiq_of_match); > > -static struct platform_device * > -vchiq_register_child(struct platform_device *pdev, const char *name) > -{ > - struct platform_device_info pdevinfo; > - struct platform_device *child; > - > - memset(&pdevinfo, 0, sizeof(pdevinfo)); > - > - pdevinfo.parent = &pdev->dev; > - pdevinfo.name = name; > - pdevinfo.id = PLATFORM_DEVID_NONE; > - pdevinfo.dma_mask = DMA_BIT_MASK(32); > - > - child = platform_device_register_full(&pdevinfo); > - if (IS_ERR(child)) { > - dev_warn(&pdev->dev, "%s not registered\n", name); > - child = NULL; > - } > - > - return child; > -} > - > static int vchiq_probe(struct platform_device *pdev) > { > struct device_node *fw_node; > @@ -1832,8 +1831,11 @@ static int vchiq_probe(struct platform_device *pdev) > goto error_exit; > } > > - bcm2835_camera = vchiq_register_child(pdev, "bcm2835-camera"); > - bcm2835_audio = vchiq_register_child(pdev, "bcm2835_audio"); > + err = platform_add_devices(vchiq_devices, ARRAY_SIZE(vchiq_devices)); > + if (err) { > + dev_warn(&pdev->dev, "Failed to add vchiq child devices"); > + goto error_exit; > + } If you unbind and rebind this driver, the platform_device instances defined as global variables will be reused, and I'm pretty sure that will cause issues, for instance with the kobj->state_initialized check in kobject_init() (called from device_initialize(), itself called from platform_device_register(), from platform_add_devices()). I'm not sure static instances of platform_device are a very good idea in general. > > return 0; > > @@ -1845,8 +1847,9 @@ static int vchiq_probe(struct platform_device *pdev) > > static int vchiq_remove(struct platform_device *pdev) > { > - platform_device_unregister(bcm2835_audio); > - platform_device_unregister(bcm2835_camera); > + for (unsigned int i = 0; i < ARRAY_SIZE(vchiq_devices); i++) > + platform_device_unregister(vchiq_devices[i]); > + > vchiq_debugfs_deinit(); > vchiq_deregister_chrdev(); > -- Regards, Laurent Pinchart