From patchwork Fri May 13 17:09:23 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shuah Khan X-Patchwork-Id: 9092621 Return-Path: X-Original-To: patchwork-linux-media@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 1B647BF29F for ; Fri, 13 May 2016 17:11:11 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id D624A20204 for ; Fri, 13 May 2016 17:11:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7FEC6201FE for ; Fri, 13 May 2016 17:11:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753534AbcEMRKA (ORCPT ); Fri, 13 May 2016 13:10:00 -0400 Received: from mailout.easymail.ca ([64.68.201.169]:40658 "EHLO mailout.easymail.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753528AbcEMRJ6 (ORCPT ); Fri, 13 May 2016 13:09:58 -0400 Received: from localhost (localhost [127.0.0.1]) by mailout.easymail.ca (Postfix) with ESMTP id 6C381A140B; Fri, 13 May 2016 13:09:29 -0400 (EDT) X-Quarantine-ID: X-Virus-Scanned: Debian amavisd-new at mailout.easymail.ca X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" X-Spam-Score: -3.695 X-Spam-Level: X-Spam-Status: No, score=-8.3 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 Received: from mailout.easymail.ca ([127.0.0.1]) by localhost (easymail-mailout.easydns.vpn [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id TDR98G9XyBok; Fri, 13 May 2016 13:09:29 -0400 (EDT) Received: from mail.gonehiking.org (c-73-181-52-62.hsd1.co.comcast.net [73.181.52.62]) by mailout.easymail.ca (Postfix) with ESMTPA id 00520A13CA; Fri, 13 May 2016 13:09:28 -0400 (EDT) Received: from shuah-XPS-13-9350.sisa.samsung.com (shuah-xps.internal [192.168.1.87]) by mail.gonehiking.org (Postfix) with ESMTP id 83F8D9F2F1; Fri, 13 May 2016 11:09:28 -0600 (MDT) From: Shuah Khan To: mchehab@osg.samsung.com, laurent.pinchart@ideasonboard.com, sakari.ailus@iki.fi, hans.verkuil@cisco.com, chehabrafael@gmail.com, javier@osg.samsung.com, inki.dae@samsung.com, g.liakhovetski@gmx.de, jh1009.sung@samsung.com Cc: Shuah Khan , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/3] media: Media Device Allocator API Date: Fri, 13 May 2016 11:09:23 -0600 Message-Id: X-Mailer: git-send-email 2.7.4 In-Reply-To: References: In-Reply-To: References: Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Media Device Allocator API to allows multiple drivers share a media device. Using this API, drivers can allocate a media device with the shared struct device as the key. Once the media device is allocated by a driver, other drivers can get a reference to it. The media device is released when all the references are released. Signed-off-by: Shuah Khan --- drivers/media/Makefile | 3 +- drivers/media/media-dev-allocator.c | 139 ++++++++++++++++++++++++++++++++++++ include/media/media-dev-allocator.h | 118 ++++++++++++++++++++++++++++++ 3 files changed, 259 insertions(+), 1 deletion(-) create mode 100644 drivers/media/media-dev-allocator.c create mode 100644 include/media/media-dev-allocator.h diff --git a/drivers/media/Makefile b/drivers/media/Makefile index e608bbc..b08f091 100644 --- a/drivers/media/Makefile +++ b/drivers/media/Makefile @@ -2,7 +2,8 @@ # Makefile for the kernel multimedia device drivers. # -media-objs := media-device.o media-devnode.o media-entity.o +media-objs := media-device.o media-devnode.o media-entity.o \ + media-dev-allocator.o # # I2C drivers should come before other drivers, otherwise they'll fail diff --git a/drivers/media/media-dev-allocator.c b/drivers/media/media-dev-allocator.c new file mode 100644 index 0000000..b49ab55 --- /dev/null +++ b/drivers/media/media-dev-allocator.c @@ -0,0 +1,139 @@ +/* + * media-dev-allocator.c - Media Controller Device Allocator API + * + * Copyright (c) 2016 Shuah Khan + * Copyright (c) 2016 Samsung Electronics Co., Ltd. + * + * This file is released under the GPLv2. + * Credits: Suggested by Laurent Pinchart + */ + +/* + * This file adds a global refcounted Media Controller Device Instance API. + * A system wide global media device list is managed and each media device + * includes a kref count. The last put on the media device releases the media + * device instance. + * +*/ + +#include +#include +#include +#include + +static LIST_HEAD(media_device_list); +static DEFINE_MUTEX(media_device_lock); + +struct media_device_instance { + struct media_device mdev; + struct list_head list; + struct device *dev; + struct kref refcount; +}; + +static inline struct media_device_instance * +to_media_device_instance(struct media_device *mdev) +{ + return container_of(mdev, struct media_device_instance, mdev); +} + +static void media_device_instance_release(struct kref *kref) +{ + struct media_device_instance *mdi = + container_of(kref, struct media_device_instance, refcount); + + dev_dbg(mdi->mdev.dev, "%s: mdev=%p\n", __func__, &mdi->mdev); + + mutex_lock(&media_device_lock); + + media_device_unregister(&mdi->mdev); + media_device_cleanup(&mdi->mdev); + + list_del(&mdi->list); + mutex_unlock(&media_device_lock); + + kfree(mdi); +} + +static struct media_device *__media_device_get(struct device *dev, + bool allocate) +{ + struct media_device_instance *mdi; + + mutex_lock(&media_device_lock); + + list_for_each_entry(mdi, &media_device_list, list) { + if (mdi->dev == dev) { + kref_get(&mdi->refcount); + dev_dbg(dev, "%s: get mdev=%p\n", + __func__, &mdi->mdev); + goto done; + } + } + + if (!allocate) { + mdi = NULL; + goto done; + } + + mdi = kzalloc(sizeof(*mdi), GFP_KERNEL); + if (!mdi) + goto done; + + mdi->dev = dev; + kref_init(&mdi->refcount); + list_add_tail(&mdi->list, &media_device_list); + + dev_dbg(dev, "%s: alloc mdev=%p\n", __func__, &mdi->mdev); + +done: + mutex_unlock(&media_device_lock); + + return mdi ? &mdi->mdev : NULL; +} + +struct media_device *media_device_allocate(struct device *dev) +{ + dev_dbg(dev, "%s\n", __func__); + return __media_device_get(dev, true); +} +EXPORT_SYMBOL_GPL(media_device_allocate); + +struct media_device *media_device_usb_allocate(struct usb_device *udev, + char *driver_name) +{ + struct media_device *mdev; + + mdev = media_device_allocate(&udev->dev); + if (!mdev) + return ERR_PTR(-ENOMEM); + + /* check if media device is already initialized */ + mutex_lock(&media_device_lock); + if (!mdev->dev) + __media_device_usb_init(mdev, udev, udev->product, + driver_name); + mutex_unlock(&media_device_lock); + + return mdev; +} +EXPORT_SYMBOL_GPL(media_device_usb_allocate); + +/* don't allocate - get reference if one is found */ +struct media_device *media_device_get(struct media_device *mdev) +{ + struct media_device_instance *mdi = to_media_device_instance(mdev); + + dev_dbg(mdi->mdev.dev, "%s: mdev=%p\n", __func__, &mdi->mdev); + return __media_device_get(mdi->dev, false); +} +EXPORT_SYMBOL_GPL(media_device_get); + +void media_device_put(struct media_device *mdev) +{ + struct media_device_instance *mdi = to_media_device_instance(mdev); + + dev_dbg(mdi->mdev.dev, "%s: mdev=%p\n", __func__, &mdi->mdev); + kref_put(&mdi->refcount, media_device_instance_release); +} +EXPORT_SYMBOL_GPL(media_device_put); diff --git a/include/media/media-dev-allocator.h b/include/media/media-dev-allocator.h new file mode 100644 index 0000000..a63dfc6 --- /dev/null +++ b/include/media/media-dev-allocator.h @@ -0,0 +1,118 @@ +/* + * media-dev-allocator.h - Media Controller Device Allocator API + * + * Copyright (c) 2016 Shuah Khan + * Copyright (c) 2016 Samsung Electronics Co., Ltd. + * + * This file is released under the GPLv2. + * Credits: Suggested by Laurent Pinchart + */ + +/* + * This file adds a global ref-counted Media Controller Device Instance API. + * A system wide global media device list is managed and each media device + * includes a kref count. The last put on the media device releases the media + * device instance. +*/ + +#ifndef _MEDIA_DEV_ALLOCTOR_H +#define _MEDIA_DEV_ALLOCTOR_H + +struct usb_device; + +#ifdef CONFIG_MEDIA_CONTROLLER +/** + * DOC: Media Controller Device Allocator API + * + * When media device belongs to more than one driver, the shared media device + * is allocated with the shared struct device as the key for look ups. + * + * Shared media device should stay in registered state until the last driver + * unregisters it. In addition, media device should be released when all the + * references are released. Each driver gets a reference to the media device + * during probe, when it allocates the media device. If media device is already + * allocated, allocate API bumps up the refcount and return the existing media + * device. Driver puts the reference back from its disconnect routine when it + * calls media_device_unregister_put(). + * + * Media device is unregistered and cleaned up from the kref put handler to + * ensure that the media device stays in registered state until the last driver + * unregisters the media device. + * + * Media Device can be in any the following states: + * + * - Allocated + * - Registered (could be tied to more than one driver) + * - Unregistered and released in the kref put handler. + * + * Driver Usage: + * + * Drivers should use the media-core routines to get register reference and + * use the media_device_unregister_put() routine to make sure the shared + * media device delete is handled correctly. + * + * driver probe: + * Call media_device_usb_allocate() to allocate or get a reference + * Call media_device_register(), if media devnode isn't registered + * + * driver disconnect: + * Call media_device_unregister_put() to put the reference. + * + */ + +/** + * media_device_usb_allocate() - Allocate and return media device + * + * @udev - struct usb_device pointer + * @driver_name + * + * This interface should be called to allocate a media device when multiple + * drivers share usb_device and the media device. This interface allocates + * media device and calls media_device_usb_init() to initialize it. + * + */ +struct media_device *media_device_usb_allocate(struct usb_device *udev, + char *driver_name); +/** + * media_device_allocate() - Allocate and return global media device + * + * @dev - struct device pointer + * + * This interface should be called to allocate media device. A new media + * device instance is created and added to the system wide media device + * instance list. If media device instance exists, media_device_allocate() + * increments the reference count and returns the media device. When more + * than one driver control the media device, the first driver to probe will + * allocate and the second driver when it calls media_device_allocate(), + * it will get a reference. + * + */ +struct media_device *media_device_allocate(struct device *dev); +/** + * media_device_get() - Get reference to a registered media device. + * + * @mdev - struct media_device pointer + * + * This interface should be called to get a reference to an allocated media + * device. + */ +struct media_device *media_device_get(struct media_device *mdev); +/** + * media_device_put() - Release media device. Calls kref_put(). + * + * @mdev - struct media_device pointer + * + * This interface should be called to put Media Device Instance kref. + */ +void media_device_put(struct media_device *mdev); +#else +static inline struct media_device *media_device_usb_allocate( + struct usb_device *udev, char *driver_name) + { return NULL; } +static inline struct media_device *media_device_allocate(struct device *dev) + { return NULL; } +static inline struct media_device *media_device_get(struct media_device *mdev) + { return NULL; } +static inline void media_device_put(struct media_device *mdev) { } +#endif /* CONFIG_MEDIA_CONTROLLER */ +#endif