From patchwork Tue Jun 11 08:23:43 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Guennadi Liakhovetski X-Patchwork-Id: 2701171 Return-Path: X-Original-To: patchwork-linux-media@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork1.kernel.org (Postfix) with ESMTP id 9290140077 for ; Tue, 11 Jun 2013 10:01:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754286Ab3FKKBO (ORCPT ); Tue, 11 Jun 2013 06:01:14 -0400 Received: from moutng.kundenserver.de ([212.227.17.9]:61684 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754180Ab3FKKBM (ORCPT ); Tue, 11 Jun 2013 06:01:12 -0400 Received: from axis700.grange (dslb-178-001-148-081.pools.arcor-ip.net [178.1.148.81]) by mrelayeu.kundenserver.de (node=mrbap0) with ESMTP (Nemesis) id 0MPIp6-1Uhx8X0aAK-004PC9; Tue, 11 Jun 2013 11:30:38 +0200 Received: from 6a.grange (unknown [192.168.1.11]) by axis700.grange (Postfix) with ESMTPS id 79CC540BD0; Tue, 11 Jun 2013 10:24:05 +0200 (CEST) Received: from lyakh by 6a.grange with local (Exim 4.72) (envelope-from ) id 1UmJs5-0002Bu-0G; Tue, 11 Jun 2013 10:24:05 +0200 From: Guennadi Liakhovetski To: linux-media@vger.kernel.org Cc: Laurent Pinchart , Sylwester Nawrocki , Hans Verkuil , linux-sh@vger.kernel.org, Magnus Damm , Sakari Ailus , Prabhakar Lad , Sascha Hauer , Guennadi Liakhovetski Subject: [PATCH v10 16/21] V4L2: support asynchronous subdevice registration Date: Tue, 11 Jun 2013 10:23:43 +0200 Message-Id: <1370939028-8352-17-git-send-email-g.liakhovetski@gmx.de> X-Mailer: git-send-email 1.7.2.5 In-Reply-To: <1370939028-8352-1-git-send-email-g.liakhovetski@gmx.de> References: <1370939028-8352-1-git-send-email-g.liakhovetski@gmx.de> X-Provags-ID: V02:K0:ttb02zQqNWnfgBLRE5xQQryP7oJKiLqGnlq3uMK9hQD rArXbLrmIj31kMHjjVp0J8h27QpPtwYUx8GncQCJ0FAdoiPdc9 nxcFNMO/6IFq9+YmWdX869yOuSb5gQGnwIhSE2o58TxqT/OgUy GDi2sd2m6zPG8Kf97jY8aOIsO3B4wxZ3drdIaaRg9pc03eD+Ye ugGzXBfVkftdDqzBRSpdOtdA8/W9WAq2nJW3Z3pz+MHfL7m6Zm 8CZ/2k08VWaDRYQKNYtCMdb/yKDMb/9PzJ2ODhwOrfToe4HHDo PLXoi5K06AFnkvpQ1KR9LGgZORFOasvCGXqxoNOwSegSThqloA +Jw8JT54sA8aiUwLC7aUUc9U2F3bhioUtEk2ojrVY4UU5oOz6t klyiMdl89lmLg== Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Currently bridge device drivers register devices for all subdevices synchronously, tupically, during their probing. E.g. if an I2C CMOS sensor is attached to a video bridge device, the bridge driver will create an I2C device and wait for the respective I2C driver to probe. This makes linking of devices straight forward, but this approach cannot be used with intrinsically asynchronous and unordered device registration systems like the Flattened Device Tree. To support such systems this patch adds an asynchronous subdevice registration framework to V4L2. To use it respective (e.g. I2C) subdevice drivers must register themselves with the framework. A bridge driver on the other hand must register notification callbacks, that will be called upon various related events. Signed-off-by: Guennadi Liakhovetski Acked-by: Lad, Prabhakar Tested-by: Lad, Prabhakar --- v10: (a) remove dynamic dev[] allocation (b) merge struct v4l2_async_hw_info into struct v4l2_async_subdev (c) change .bound(), .unbind() prototypes - thanks to Laurent for a patch (d) improve struct comment (e) remove an unused variable in v4l2_async_unregister_subdev() (f) lock the device, when dereferencing dev->driver (g) fix a false success in v4l2_async_belongs() drivers/media/v4l2-core/Makefile | 3 +- drivers/media/v4l2-core/v4l2-async.c | 280 ++++++++++++++++++++++++++++++++++ include/media/v4l2-async.h | 105 +++++++++++++ include/media/v4l2-subdev.h | 8 + 4 files changed, 395 insertions(+), 1 deletions(-) create mode 100644 drivers/media/v4l2-core/v4l2-async.c create mode 100644 include/media/v4l2-async.h diff --git a/drivers/media/v4l2-core/Makefile b/drivers/media/v4l2-core/Makefile index 628c630..4c33b8d6 100644 --- a/drivers/media/v4l2-core/Makefile +++ b/drivers/media/v4l2-core/Makefile @@ -5,7 +5,8 @@ tuner-objs := tuner-core.o videodev-objs := v4l2-dev.o v4l2-ioctl.o v4l2-device.o v4l2-fh.o \ - v4l2-event.o v4l2-ctrls.o v4l2-subdev.o v4l2-clk.o + v4l2-event.o v4l2-ctrls.o v4l2-subdev.o v4l2-clk.o \ + v4l2-async.o ifeq ($(CONFIG_COMPAT),y) videodev-objs += v4l2-compat-ioctl32.o endif diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c new file mode 100644 index 0000000..3590ccc --- /dev/null +++ b/drivers/media/v4l2-core/v4l2-async.c @@ -0,0 +1,280 @@ +/* + * V4L2 asynchronous subdevice registration API + * + * Copyright (C) 2012-2013, Guennadi Liakhovetski + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include + +static bool match_i2c(struct device *dev, struct v4l2_async_subdev *asd) +{ + struct i2c_client *client = i2c_verify_client(dev); + return client && + asd->bus_type == V4L2_ASYNC_BUS_I2C && + asd->match.i2c.adapter_id == client->adapter->nr && + asd->match.i2c.address == client->addr; +} + +static bool match_platform(struct device *dev, struct v4l2_async_subdev *asd) +{ + return asd->bus_type == V4L2_ASYNC_BUS_PLATFORM && + !strcmp(asd->match.platform.name, dev_name(dev)); +} + +static LIST_HEAD(subdev_list); +static LIST_HEAD(notifier_list); +static DEFINE_MUTEX(list_lock); + +static struct v4l2_async_subdev *v4l2_async_belongs(struct v4l2_async_notifier *notifier, + struct v4l2_async_subdev_list *asdl) +{ + struct v4l2_subdev *sd = v4l2_async_to_subdev(asdl); + struct v4l2_async_subdev *asd; + bool (*match)(struct device *, + struct v4l2_async_subdev *); + + list_for_each_entry(asd, ¬ifier->waiting, list) { + /* bus_type has been verified valid before */ + switch (asd->bus_type) { + case V4L2_ASYNC_BUS_CUSTOM: + match = asd->match.custom.match; + if (!match) + /* Match always */ + return asd; + break; + case V4L2_ASYNC_BUS_PLATFORM: + match = match_platform; + break; + case V4L2_ASYNC_BUS_I2C: + match = match_i2c; + break; + default: + /* Cannot happen, unless someone breaks us */ + WARN_ON(true); + return NULL; + } + + /* match cannot be NULL here */ + if (match(sd->dev, asd)) + return asd; + } + + return NULL; +} + +static int v4l2_async_test_notify(struct v4l2_async_notifier *notifier, + struct v4l2_async_subdev_list *asdl, + struct v4l2_async_subdev *asd) +{ + struct v4l2_subdev *sd = v4l2_async_to_subdev(asdl); + int ret; + + /* Remove from the waiting list */ + list_del(&asd->list); + asdl->asd = asd; + asdl->notifier = notifier; + + if (notifier->bound) { + ret = notifier->bound(notifier, sd, asd); + if (ret < 0) + return ret; + } + /* Move from the global subdevice list to notifier's done */ + list_move(&asdl->list, ¬ifier->done); + + ret = v4l2_device_register_subdev(notifier->v4l2_dev, sd); + if (ret < 0) { + if (notifier->unbind) + notifier->unbind(notifier, sd, asd); + return ret; + } + + if (list_empty(¬ifier->waiting) && notifier->complete) + return notifier->complete(notifier); + + return 0; +} + +static void v4l2_async_cleanup(struct v4l2_async_subdev_list *asdl) +{ + struct v4l2_subdev *sd = v4l2_async_to_subdev(asdl); + + v4l2_device_unregister_subdev(sd); + /* Subdevice driver will reprobe and put asdl back onto the list */ + list_del_init(&asdl->list); + asdl->asd = NULL; + sd->dev = NULL; +} + +int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev, + struct v4l2_async_notifier *notifier) +{ + struct v4l2_async_subdev_list *asdl, *tmp; + struct v4l2_async_subdev *asd; + int i; + + if (!notifier->subdev_num || notifier->subdev_num > V4L2_MAX_SUBDEVS) + return -EINVAL; + + notifier->v4l2_dev = v4l2_dev; + INIT_LIST_HEAD(¬ifier->waiting); + INIT_LIST_HEAD(¬ifier->done); + + for (i = 0; i < notifier->subdev_num; i++) { + asd = notifier->subdev[i]; + + switch (asd->bus_type) { + case V4L2_ASYNC_BUS_CUSTOM: + case V4L2_ASYNC_BUS_PLATFORM: + case V4L2_ASYNC_BUS_I2C: + break; + default: + dev_err(notifier->v4l2_dev ? notifier->v4l2_dev->dev : NULL, + "Invalid bus-type %u on %p\n", + asd->bus_type, asd); + return -EINVAL; + } + list_add_tail(&asd->list, ¬ifier->waiting); + } + + mutex_lock(&list_lock); + + /* Keep also completed notifiers on the list */ + list_add(¬ifier->list, ¬ifier_list); + + list_for_each_entry_safe(asdl, tmp, &subdev_list, list) { + int ret; + + asd = v4l2_async_belongs(notifier, asdl); + if (!asd) + continue; + + ret = v4l2_async_test_notify(notifier, asdl, asd); + if (ret < 0) { + mutex_unlock(&list_lock); + return ret; + } + } + + mutex_unlock(&list_lock); + + return 0; +} +EXPORT_SYMBOL(v4l2_async_notifier_register); + +void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier) +{ + struct v4l2_async_subdev_list *asdl, *tmp; + unsigned int notif_n_subdev = notifier->subdev_num; + unsigned int n_subdev = min(notif_n_subdev, V4L2_MAX_SUBDEVS); + struct device *dev[n_subdev]; + int i = 0; + + mutex_lock(&list_lock); + + list_del(¬ifier->list); + + list_for_each_entry_safe(asdl, tmp, ¬ifier->done, list) { + struct v4l2_subdev *sd = v4l2_async_to_subdev(asdl); + + dev[i] = get_device(sd->dev); + + v4l2_async_cleanup(asdl); + + /* If we handled USB devices, we'd have to lock the parent too */ + device_release_driver(dev[i++]); + + if (notifier->unbind) + notifier->unbind(notifier, sd, sd->asdl.asd); + } + + mutex_unlock(&list_lock); + + while (i--) { + struct device *d = dev[i]; + + if (d && device_attach(d) < 0) { + const char *name = "(none)"; + int lock = device_trylock(d); + + if (lock && d->driver) + name = d->driver->name; + dev_err(d, "Failed to re-probe to %s\n", name); + if (lock) + device_unlock(d); + } + put_device(d); + } + /* + * Don't care about the waiting list, it is initialised and populated + * upon notifier registration. + */ +} +EXPORT_SYMBOL(v4l2_async_notifier_unregister); + +int v4l2_async_register_subdev(struct v4l2_subdev *sd) +{ + struct v4l2_async_subdev_list *asdl = &sd->asdl; + struct v4l2_async_notifier *notifier; + + mutex_lock(&list_lock); + + INIT_LIST_HEAD(&asdl->list); + + list_for_each_entry(notifier, ¬ifier_list, list) { + struct v4l2_async_subdev *asd = v4l2_async_belongs(notifier, asdl); + if (asd) { + int ret = v4l2_async_test_notify(notifier, asdl, asd); + mutex_unlock(&list_lock); + return ret; + } + } + + /* None matched, wait for hot-plugging */ + list_add(&asdl->list, &subdev_list); + + mutex_unlock(&list_lock); + + return 0; +} +EXPORT_SYMBOL(v4l2_async_register_subdev); + +void v4l2_async_unregister_subdev(struct v4l2_subdev *sd) +{ + struct v4l2_async_subdev_list *asdl = &sd->asdl; + struct v4l2_async_notifier *notifier = asdl->notifier; + + if (!asdl->asd) { + if (!list_empty(&asdl->list)) + v4l2_async_cleanup(asdl); + return; + } + + mutex_lock(&list_lock); + + list_add(&asdl->asd->list, ¬ifier->waiting); + + v4l2_async_cleanup(asdl); + + if (notifier->unbind) + notifier->unbind(notifier, sd, sd->asdl.asd); + + mutex_unlock(&list_lock); +} +EXPORT_SYMBOL(v4l2_async_unregister_subdev); diff --git a/include/media/v4l2-async.h b/include/media/v4l2-async.h new file mode 100644 index 0000000..12bd39c --- /dev/null +++ b/include/media/v4l2-async.h @@ -0,0 +1,105 @@ +/* + * V4L2 asynchronous subdevice registration API + * + * Copyright (C) 2012-2013, Guennadi Liakhovetski + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#ifndef V4L2_ASYNC_H +#define V4L2_ASYNC_H + +#include +#include + +struct device; +struct v4l2_device; +struct v4l2_subdev; +struct v4l2_async_notifier; + +/* A random max subdevice number, used to allocate an array on stack */ +#define V4L2_MAX_SUBDEVS 128U + +enum v4l2_async_bus_type { + V4L2_ASYNC_BUS_CUSTOM, + V4L2_ASYNC_BUS_PLATFORM, + V4L2_ASYNC_BUS_I2C, +}; + +/** + * struct v4l2_async_subdev - sub-device descriptor, as known to a bridge + * @bus_type: subdevice bus type to select the appropriate matching method + * @match: union of per-bus type matching data sets + * @list: used to link struct v4l2_async_subdev objects, waiting to be + * probed, to a notifier->waiting list + */ +struct v4l2_async_subdev { + enum v4l2_async_bus_type bus_type; + union { + struct { + const char *name; + } platform; + struct { + int adapter_id; + unsigned short address; + } i2c; + struct { + bool (*match)(struct device *, + struct v4l2_async_subdev *); + void *priv; + } custom; + } match; + + /* v4l2-async core private: not to be used by drivers */ + struct list_head list; +}; + +/** + * v4l2_async_subdev_list - provided by subdevices + * @list: links struct v4l2_async_subdev_list objects to a global list + * before probing, and onto notifier->done after probing + * @asd: pointer to respective struct v4l2_async_subdev + * @notifier: pointer to managing notifier + */ +struct v4l2_async_subdev_list { + struct list_head list; + struct v4l2_async_subdev *asd; + struct v4l2_async_notifier *notifier; +}; + +/** + * v4l2_async_notifier - v4l2_device notifier data + * @subdev_num: number of subdevices + * @subdev: array of pointers to subdevices + * @v4l2_dev: pointer to struct v4l2_device + * @waiting: list of struct v4l2_async_subdev, waiting for their drivers + * @done: list of struct v4l2_async_subdev_list, already probed + * @list: member in a global list of notifiers + * @bound: a subdevice driver has successfully probed one of subdevices + * @complete: all subdevices have been probed successfully + * @unbind: a subdevice is leaving + */ +struct v4l2_async_notifier { + unsigned int subdev_num; + struct v4l2_async_subdev **subdev; + struct v4l2_device *v4l2_dev; + struct list_head waiting; + struct list_head done; + struct list_head list; + int (*bound)(struct v4l2_async_notifier *notifier, + struct v4l2_subdev *subdev, + struct v4l2_async_subdev *asd); + int (*complete)(struct v4l2_async_notifier *notifier); + void (*unbind)(struct v4l2_async_notifier *notifier, + struct v4l2_subdev *subdev, + struct v4l2_async_subdev *asd); +}; + +int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev, + struct v4l2_async_notifier *notifier); +void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier); +int v4l2_async_register_subdev(struct v4l2_subdev *sd); +void v4l2_async_unregister_subdev(struct v4l2_subdev *sd); +#endif diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h index d8756fa..21174af 100644 --- a/include/media/v4l2-subdev.h +++ b/include/media/v4l2-subdev.h @@ -24,6 +24,7 @@ #include #include #include +#include #include #include #include @@ -587,8 +588,15 @@ struct v4l2_subdev { struct video_device *devnode; /* pointer to the physical device */ struct device *dev; + struct v4l2_async_subdev_list asdl; }; +static inline struct v4l2_subdev *v4l2_async_to_subdev( + struct v4l2_async_subdev_list *asdl) +{ + return container_of(asdl, struct v4l2_subdev, asdl); +} + #define media_entity_to_v4l2_subdev(ent) \ container_of(ent, struct v4l2_subdev, entity) #define vdev_to_v4l2_subdev(vdev) \