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![Christoph Hellwig](/assets/img/avatar_default.png)
This goes through a lot of hooks just to call arch_teardown_dma_ops. Replace it with a direct call instead. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Robin Murphy <robin.murphy@arm.com>
1054 lines
28 KiB
C
1054 lines
28 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* drivers/base/dd.c - The core device/driver interactions.
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*
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* This file contains the (sometimes tricky) code that controls the
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* interactions between devices and drivers, which primarily includes
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* driver binding and unbinding.
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*
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* All of this code used to exist in drivers/base/bus.c, but was
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* relocated to here in the name of compartmentalization (since it wasn't
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* strictly code just for the 'struct bus_type'.
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*
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* Copyright (c) 2002-5 Patrick Mochel
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* Copyright (c) 2002-3 Open Source Development Labs
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* Copyright (c) 2007-2009 Greg Kroah-Hartman <gregkh@suse.de>
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* Copyright (c) 2007-2009 Novell Inc.
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*/
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#include <linux/debugfs.h>
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#include <linux/device.h>
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#include <linux/delay.h>
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#include <linux/dma-mapping.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/kthread.h>
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#include <linux/wait.h>
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#include <linux/async.h>
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#include <linux/pm_runtime.h>
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#include <linux/pinctrl/devinfo.h>
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#include "base.h"
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#include "power/power.h"
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/*
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* Deferred Probe infrastructure.
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*
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* Sometimes driver probe order matters, but the kernel doesn't always have
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* dependency information which means some drivers will get probed before a
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* resource it depends on is available. For example, an SDHCI driver may
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* first need a GPIO line from an i2c GPIO controller before it can be
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* initialized. If a required resource is not available yet, a driver can
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* request probing to be deferred by returning -EPROBE_DEFER from its probe hook
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*
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* Deferred probe maintains two lists of devices, a pending list and an active
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* list. A driver returning -EPROBE_DEFER causes the device to be added to the
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* pending list. A successful driver probe will trigger moving all devices
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* from the pending to the active list so that the workqueue will eventually
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* retry them.
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*
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* The deferred_probe_mutex must be held any time the deferred_probe_*_list
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* of the (struct device*)->p->deferred_probe pointers are manipulated
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*/
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static DEFINE_MUTEX(deferred_probe_mutex);
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static LIST_HEAD(deferred_probe_pending_list);
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static LIST_HEAD(deferred_probe_active_list);
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static atomic_t deferred_trigger_count = ATOMIC_INIT(0);
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static struct dentry *deferred_devices;
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static bool initcalls_done;
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/*
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* In some cases, like suspend to RAM or hibernation, It might be reasonable
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* to prohibit probing of devices as it could be unsafe.
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* Once defer_all_probes is true all drivers probes will be forcibly deferred.
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*/
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static bool defer_all_probes;
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/*
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* deferred_probe_work_func() - Retry probing devices in the active list.
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*/
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static void deferred_probe_work_func(struct work_struct *work)
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{
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struct device *dev;
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struct device_private *private;
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/*
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* This block processes every device in the deferred 'active' list.
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* Each device is removed from the active list and passed to
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* bus_probe_device() to re-attempt the probe. The loop continues
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* until every device in the active list is removed and retried.
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*
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* Note: Once the device is removed from the list and the mutex is
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* released, it is possible for the device get freed by another thread
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* and cause a illegal pointer dereference. This code uses
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* get/put_device() to ensure the device structure cannot disappear
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* from under our feet.
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*/
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mutex_lock(&deferred_probe_mutex);
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while (!list_empty(&deferred_probe_active_list)) {
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private = list_first_entry(&deferred_probe_active_list,
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typeof(*dev->p), deferred_probe);
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dev = private->device;
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list_del_init(&private->deferred_probe);
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get_device(dev);
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/*
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* Drop the mutex while probing each device; the probe path may
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* manipulate the deferred list
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*/
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mutex_unlock(&deferred_probe_mutex);
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/*
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* Force the device to the end of the dpm_list since
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* the PM code assumes that the order we add things to
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* the list is a good order for suspend but deferred
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* probe makes that very unsafe.
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*/
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device_pm_move_to_tail(dev);
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dev_dbg(dev, "Retrying from deferred list\n");
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bus_probe_device(dev);
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mutex_lock(&deferred_probe_mutex);
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put_device(dev);
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}
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mutex_unlock(&deferred_probe_mutex);
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}
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static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func);
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static void driver_deferred_probe_add(struct device *dev)
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{
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mutex_lock(&deferred_probe_mutex);
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if (list_empty(&dev->p->deferred_probe)) {
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dev_dbg(dev, "Added to deferred list\n");
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list_add_tail(&dev->p->deferred_probe, &deferred_probe_pending_list);
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}
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mutex_unlock(&deferred_probe_mutex);
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}
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void driver_deferred_probe_del(struct device *dev)
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{
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mutex_lock(&deferred_probe_mutex);
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if (!list_empty(&dev->p->deferred_probe)) {
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dev_dbg(dev, "Removed from deferred list\n");
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list_del_init(&dev->p->deferred_probe);
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}
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mutex_unlock(&deferred_probe_mutex);
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}
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static bool driver_deferred_probe_enable = false;
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/**
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* driver_deferred_probe_trigger() - Kick off re-probing deferred devices
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*
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* This functions moves all devices from the pending list to the active
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* list and schedules the deferred probe workqueue to process them. It
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* should be called anytime a driver is successfully bound to a device.
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*
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* Note, there is a race condition in multi-threaded probe. In the case where
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* more than one device is probing at the same time, it is possible for one
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* probe to complete successfully while another is about to defer. If the second
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* depends on the first, then it will get put on the pending list after the
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* trigger event has already occurred and will be stuck there.
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*
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* The atomic 'deferred_trigger_count' is used to determine if a successful
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* trigger has occurred in the midst of probing a driver. If the trigger count
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* changes in the midst of a probe, then deferred processing should be triggered
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* again.
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*/
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static void driver_deferred_probe_trigger(void)
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{
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if (!driver_deferred_probe_enable)
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return;
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/*
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* A successful probe means that all the devices in the pending list
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* should be triggered to be reprobed. Move all the deferred devices
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* into the active list so they can be retried by the workqueue
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*/
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mutex_lock(&deferred_probe_mutex);
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atomic_inc(&deferred_trigger_count);
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list_splice_tail_init(&deferred_probe_pending_list,
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&deferred_probe_active_list);
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mutex_unlock(&deferred_probe_mutex);
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/*
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* Kick the re-probe thread. It may already be scheduled, but it is
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* safe to kick it again.
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*/
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schedule_work(&deferred_probe_work);
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}
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/**
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* device_block_probing() - Block/defere device's probes
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*
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* It will disable probing of devices and defer their probes instead.
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*/
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void device_block_probing(void)
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{
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defer_all_probes = true;
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/* sync with probes to avoid races. */
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wait_for_device_probe();
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}
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/**
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* device_unblock_probing() - Unblock/enable device's probes
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*
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* It will restore normal behavior and trigger re-probing of deferred
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* devices.
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*/
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void device_unblock_probing(void)
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{
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defer_all_probes = false;
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driver_deferred_probe_trigger();
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}
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/*
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* deferred_devs_show() - Show the devices in the deferred probe pending list.
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*/
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static int deferred_devs_show(struct seq_file *s, void *data)
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{
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struct device_private *curr;
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mutex_lock(&deferred_probe_mutex);
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list_for_each_entry(curr, &deferred_probe_pending_list, deferred_probe)
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seq_printf(s, "%s\n", dev_name(curr->device));
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mutex_unlock(&deferred_probe_mutex);
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return 0;
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}
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DEFINE_SHOW_ATTRIBUTE(deferred_devs);
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static int deferred_probe_timeout = -1;
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static int __init deferred_probe_timeout_setup(char *str)
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{
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deferred_probe_timeout = simple_strtol(str, NULL, 10);
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return 1;
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}
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__setup("deferred_probe_timeout=", deferred_probe_timeout_setup);
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/**
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* driver_deferred_probe_check_state() - Check deferred probe state
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* @dev: device to check
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*
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* Returns -ENODEV if init is done and all built-in drivers have had a chance
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* to probe (i.e. initcalls are done), -ETIMEDOUT if deferred probe debug
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* timeout has expired, or -EPROBE_DEFER if none of those conditions are met.
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*
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* Drivers or subsystems can opt-in to calling this function instead of directly
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* returning -EPROBE_DEFER.
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*/
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int driver_deferred_probe_check_state(struct device *dev)
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{
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if (initcalls_done) {
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if (!deferred_probe_timeout) {
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dev_WARN(dev, "deferred probe timeout, ignoring dependency");
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return -ETIMEDOUT;
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}
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dev_warn(dev, "ignoring dependency for device, assuming no driver");
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return -ENODEV;
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}
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return -EPROBE_DEFER;
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}
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static void deferred_probe_timeout_work_func(struct work_struct *work)
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{
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struct device_private *private, *p;
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deferred_probe_timeout = 0;
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driver_deferred_probe_trigger();
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flush_work(&deferred_probe_work);
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list_for_each_entry_safe(private, p, &deferred_probe_pending_list, deferred_probe)
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dev_info(private->device, "deferred probe pending");
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}
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static DECLARE_DELAYED_WORK(deferred_probe_timeout_work, deferred_probe_timeout_work_func);
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/**
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* deferred_probe_initcall() - Enable probing of deferred devices
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*
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* We don't want to get in the way when the bulk of drivers are getting probed.
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* Instead, this initcall makes sure that deferred probing is delayed until
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* late_initcall time.
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*/
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static int deferred_probe_initcall(void)
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{
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deferred_devices = debugfs_create_file("devices_deferred", 0444, NULL,
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NULL, &deferred_devs_fops);
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driver_deferred_probe_enable = true;
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driver_deferred_probe_trigger();
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/* Sort as many dependencies as possible before exiting initcalls */
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flush_work(&deferred_probe_work);
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initcalls_done = true;
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/*
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* Trigger deferred probe again, this time we won't defer anything
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* that is optional
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*/
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driver_deferred_probe_trigger();
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flush_work(&deferred_probe_work);
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if (deferred_probe_timeout > 0) {
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schedule_delayed_work(&deferred_probe_timeout_work,
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deferred_probe_timeout * HZ);
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}
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return 0;
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}
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late_initcall(deferred_probe_initcall);
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static void __exit deferred_probe_exit(void)
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{
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debugfs_remove_recursive(deferred_devices);
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}
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__exitcall(deferred_probe_exit);
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/**
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* device_is_bound() - Check if device is bound to a driver
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* @dev: device to check
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*
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* Returns true if passed device has already finished probing successfully
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* against a driver.
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*
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* This function must be called with the device lock held.
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*/
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bool device_is_bound(struct device *dev)
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{
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return dev->p && klist_node_attached(&dev->p->knode_driver);
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}
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static void driver_bound(struct device *dev)
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{
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if (device_is_bound(dev)) {
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printk(KERN_WARNING "%s: device %s already bound\n",
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__func__, kobject_name(&dev->kobj));
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return;
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}
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pr_debug("driver: '%s': %s: bound to device '%s'\n", dev->driver->name,
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__func__, dev_name(dev));
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klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices);
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device_links_driver_bound(dev);
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device_pm_check_callbacks(dev);
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/*
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* Make sure the device is no longer in one of the deferred lists and
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* kick off retrying all pending devices
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*/
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driver_deferred_probe_del(dev);
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driver_deferred_probe_trigger();
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if (dev->bus)
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blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
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BUS_NOTIFY_BOUND_DRIVER, dev);
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kobject_uevent(&dev->kobj, KOBJ_BIND);
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}
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static ssize_t coredump_store(struct device *dev, struct device_attribute *attr,
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const char *buf, size_t count)
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{
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device_lock(dev);
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dev->driver->coredump(dev);
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device_unlock(dev);
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return count;
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}
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static DEVICE_ATTR_WO(coredump);
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static int driver_sysfs_add(struct device *dev)
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{
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int ret;
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|
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if (dev->bus)
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blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
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BUS_NOTIFY_BIND_DRIVER, dev);
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ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj,
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kobject_name(&dev->kobj));
|
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if (ret)
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goto fail;
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ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj,
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"driver");
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if (ret)
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goto rm_dev;
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|
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if (!IS_ENABLED(CONFIG_DEV_COREDUMP) || !dev->driver->coredump ||
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!device_create_file(dev, &dev_attr_coredump))
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return 0;
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sysfs_remove_link(&dev->kobj, "driver");
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rm_dev:
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sysfs_remove_link(&dev->driver->p->kobj,
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kobject_name(&dev->kobj));
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|
|
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fail:
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return ret;
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}
|
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|
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static void driver_sysfs_remove(struct device *dev)
|
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{
|
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struct device_driver *drv = dev->driver;
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|
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if (drv) {
|
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if (drv->coredump)
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device_remove_file(dev, &dev_attr_coredump);
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sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj));
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sysfs_remove_link(&dev->kobj, "driver");
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}
|
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}
|
|
|
|
/**
|
|
* device_bind_driver - bind a driver to one device.
|
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* @dev: device.
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*
|
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* Allow manual attachment of a driver to a device.
|
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* Caller must have already set @dev->driver.
|
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*
|
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* Note that this does not modify the bus reference count
|
|
* nor take the bus's rwsem. Please verify those are accounted
|
|
* for before calling this. (It is ok to call with no other effort
|
|
* from a driver's probe() method.)
|
|
*
|
|
* This function must be called with the device lock held.
|
|
*/
|
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int device_bind_driver(struct device *dev)
|
|
{
|
|
int ret;
|
|
|
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ret = driver_sysfs_add(dev);
|
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if (!ret)
|
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driver_bound(dev);
|
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else if (dev->bus)
|
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blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
|
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BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
|
|
return ret;
|
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}
|
|
EXPORT_SYMBOL_GPL(device_bind_driver);
|
|
|
|
static atomic_t probe_count = ATOMIC_INIT(0);
|
|
static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);
|
|
|
|
static void driver_deferred_probe_add_trigger(struct device *dev,
|
|
int local_trigger_count)
|
|
{
|
|
driver_deferred_probe_add(dev);
|
|
/* Did a trigger occur while probing? Need to re-trigger if yes */
|
|
if (local_trigger_count != atomic_read(&deferred_trigger_count))
|
|
driver_deferred_probe_trigger();
|
|
}
|
|
|
|
static int really_probe(struct device *dev, struct device_driver *drv)
|
|
{
|
|
int ret = -EPROBE_DEFER;
|
|
int local_trigger_count = atomic_read(&deferred_trigger_count);
|
|
bool test_remove = IS_ENABLED(CONFIG_DEBUG_TEST_DRIVER_REMOVE) &&
|
|
!drv->suppress_bind_attrs;
|
|
|
|
if (defer_all_probes) {
|
|
/*
|
|
* Value of defer_all_probes can be set only by
|
|
* device_defer_all_probes_enable() which, in turn, will call
|
|
* wait_for_device_probe() right after that to avoid any races.
|
|
*/
|
|
dev_dbg(dev, "Driver %s force probe deferral\n", drv->name);
|
|
driver_deferred_probe_add(dev);
|
|
return ret;
|
|
}
|
|
|
|
ret = device_links_check_suppliers(dev);
|
|
if (ret == -EPROBE_DEFER)
|
|
driver_deferred_probe_add_trigger(dev, local_trigger_count);
|
|
if (ret)
|
|
return ret;
|
|
|
|
atomic_inc(&probe_count);
|
|
pr_debug("bus: '%s': %s: probing driver %s with device %s\n",
|
|
drv->bus->name, __func__, drv->name, dev_name(dev));
|
|
WARN_ON(!list_empty(&dev->devres_head));
|
|
|
|
re_probe:
|
|
dev->driver = drv;
|
|
|
|
/* If using pinctrl, bind pins now before probing */
|
|
ret = pinctrl_bind_pins(dev);
|
|
if (ret)
|
|
goto pinctrl_bind_failed;
|
|
|
|
if (dev->bus->dma_configure) {
|
|
ret = dev->bus->dma_configure(dev);
|
|
if (ret)
|
|
goto dma_failed;
|
|
}
|
|
|
|
if (driver_sysfs_add(dev)) {
|
|
printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n",
|
|
__func__, dev_name(dev));
|
|
goto probe_failed;
|
|
}
|
|
|
|
if (dev->pm_domain && dev->pm_domain->activate) {
|
|
ret = dev->pm_domain->activate(dev);
|
|
if (ret)
|
|
goto probe_failed;
|
|
}
|
|
|
|
if (dev->bus->probe) {
|
|
ret = dev->bus->probe(dev);
|
|
if (ret)
|
|
goto probe_failed;
|
|
} else if (drv->probe) {
|
|
ret = drv->probe(dev);
|
|
if (ret)
|
|
goto probe_failed;
|
|
}
|
|
|
|
if (test_remove) {
|
|
test_remove = false;
|
|
|
|
if (dev->bus->remove)
|
|
dev->bus->remove(dev);
|
|
else if (drv->remove)
|
|
drv->remove(dev);
|
|
|
|
devres_release_all(dev);
|
|
driver_sysfs_remove(dev);
|
|
dev->driver = NULL;
|
|
dev_set_drvdata(dev, NULL);
|
|
if (dev->pm_domain && dev->pm_domain->dismiss)
|
|
dev->pm_domain->dismiss(dev);
|
|
pm_runtime_reinit(dev);
|
|
|
|
goto re_probe;
|
|
}
|
|
|
|
pinctrl_init_done(dev);
|
|
|
|
if (dev->pm_domain && dev->pm_domain->sync)
|
|
dev->pm_domain->sync(dev);
|
|
|
|
driver_bound(dev);
|
|
ret = 1;
|
|
pr_debug("bus: '%s': %s: bound device %s to driver %s\n",
|
|
drv->bus->name, __func__, dev_name(dev), drv->name);
|
|
goto done;
|
|
|
|
probe_failed:
|
|
arch_teardown_dma_ops(dev);
|
|
dma_failed:
|
|
if (dev->bus)
|
|
blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
|
|
BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
|
|
pinctrl_bind_failed:
|
|
device_links_no_driver(dev);
|
|
devres_release_all(dev);
|
|
driver_sysfs_remove(dev);
|
|
dev->driver = NULL;
|
|
dev_set_drvdata(dev, NULL);
|
|
if (dev->pm_domain && dev->pm_domain->dismiss)
|
|
dev->pm_domain->dismiss(dev);
|
|
pm_runtime_reinit(dev);
|
|
dev_pm_set_driver_flags(dev, 0);
|
|
|
|
switch (ret) {
|
|
case -EPROBE_DEFER:
|
|
/* Driver requested deferred probing */
|
|
dev_dbg(dev, "Driver %s requests probe deferral\n", drv->name);
|
|
driver_deferred_probe_add_trigger(dev, local_trigger_count);
|
|
break;
|
|
case -ENODEV:
|
|
case -ENXIO:
|
|
pr_debug("%s: probe of %s rejects match %d\n",
|
|
drv->name, dev_name(dev), ret);
|
|
break;
|
|
default:
|
|
/* driver matched but the probe failed */
|
|
printk(KERN_WARNING
|
|
"%s: probe of %s failed with error %d\n",
|
|
drv->name, dev_name(dev), ret);
|
|
}
|
|
/*
|
|
* Ignore errors returned by ->probe so that the next driver can try
|
|
* its luck.
|
|
*/
|
|
ret = 0;
|
|
done:
|
|
atomic_dec(&probe_count);
|
|
wake_up(&probe_waitqueue);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* For initcall_debug, show the driver probe time.
|
|
*/
|
|
static int really_probe_debug(struct device *dev, struct device_driver *drv)
|
|
{
|
|
ktime_t calltime, delta, rettime;
|
|
int ret;
|
|
|
|
calltime = ktime_get();
|
|
ret = really_probe(dev, drv);
|
|
rettime = ktime_get();
|
|
delta = ktime_sub(rettime, calltime);
|
|
printk(KERN_DEBUG "probe of %s returned %d after %lld usecs\n",
|
|
dev_name(dev), ret, (s64) ktime_to_us(delta));
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* driver_probe_done
|
|
* Determine if the probe sequence is finished or not.
|
|
*
|
|
* Should somehow figure out how to use a semaphore, not an atomic variable...
|
|
*/
|
|
int driver_probe_done(void)
|
|
{
|
|
pr_debug("%s: probe_count = %d\n", __func__,
|
|
atomic_read(&probe_count));
|
|
if (atomic_read(&probe_count))
|
|
return -EBUSY;
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* wait_for_device_probe
|
|
* Wait for device probing to be completed.
|
|
*/
|
|
void wait_for_device_probe(void)
|
|
{
|
|
/* wait for the deferred probe workqueue to finish */
|
|
flush_work(&deferred_probe_work);
|
|
|
|
/* wait for the known devices to complete their probing */
|
|
wait_event(probe_waitqueue, atomic_read(&probe_count) == 0);
|
|
async_synchronize_full();
|
|
}
|
|
EXPORT_SYMBOL_GPL(wait_for_device_probe);
|
|
|
|
/**
|
|
* driver_probe_device - attempt to bind device & driver together
|
|
* @drv: driver to bind a device to
|
|
* @dev: device to try to bind to the driver
|
|
*
|
|
* This function returns -ENODEV if the device is not registered,
|
|
* 1 if the device is bound successfully and 0 otherwise.
|
|
*
|
|
* This function must be called with @dev lock held. When called for a
|
|
* USB interface, @dev->parent lock must be held as well.
|
|
*
|
|
* If the device has a parent, runtime-resume the parent before driver probing.
|
|
*/
|
|
int driver_probe_device(struct device_driver *drv, struct device *dev)
|
|
{
|
|
int ret = 0;
|
|
|
|
if (!device_is_registered(dev))
|
|
return -ENODEV;
|
|
|
|
pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
|
|
drv->bus->name, __func__, dev_name(dev), drv->name);
|
|
|
|
pm_runtime_get_suppliers(dev);
|
|
if (dev->parent)
|
|
pm_runtime_get_sync(dev->parent);
|
|
|
|
pm_runtime_barrier(dev);
|
|
if (initcall_debug)
|
|
ret = really_probe_debug(dev, drv);
|
|
else
|
|
ret = really_probe(dev, drv);
|
|
pm_request_idle(dev);
|
|
|
|
if (dev->parent)
|
|
pm_runtime_put(dev->parent);
|
|
|
|
pm_runtime_put_suppliers(dev);
|
|
return ret;
|
|
}
|
|
|
|
bool driver_allows_async_probing(struct device_driver *drv)
|
|
{
|
|
switch (drv->probe_type) {
|
|
case PROBE_PREFER_ASYNCHRONOUS:
|
|
return true;
|
|
|
|
case PROBE_FORCE_SYNCHRONOUS:
|
|
return false;
|
|
|
|
default:
|
|
if (module_requested_async_probing(drv->owner))
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
}
|
|
|
|
struct device_attach_data {
|
|
struct device *dev;
|
|
|
|
/*
|
|
* Indicates whether we are are considering asynchronous probing or
|
|
* not. Only initial binding after device or driver registration
|
|
* (including deferral processing) may be done asynchronously, the
|
|
* rest is always synchronous, as we expect it is being done by
|
|
* request from userspace.
|
|
*/
|
|
bool check_async;
|
|
|
|
/*
|
|
* Indicates if we are binding synchronous or asynchronous drivers.
|
|
* When asynchronous probing is enabled we'll execute 2 passes
|
|
* over drivers: first pass doing synchronous probing and second
|
|
* doing asynchronous probing (if synchronous did not succeed -
|
|
* most likely because there was no driver requiring synchronous
|
|
* probing - and we found asynchronous driver during first pass).
|
|
* The 2 passes are done because we can't shoot asynchronous
|
|
* probe for given device and driver from bus_for_each_drv() since
|
|
* driver pointer is not guaranteed to stay valid once
|
|
* bus_for_each_drv() iterates to the next driver on the bus.
|
|
*/
|
|
bool want_async;
|
|
|
|
/*
|
|
* We'll set have_async to 'true' if, while scanning for matching
|
|
* driver, we'll encounter one that requests asynchronous probing.
|
|
*/
|
|
bool have_async;
|
|
};
|
|
|
|
static int __device_attach_driver(struct device_driver *drv, void *_data)
|
|
{
|
|
struct device_attach_data *data = _data;
|
|
struct device *dev = data->dev;
|
|
bool async_allowed;
|
|
int ret;
|
|
|
|
/*
|
|
* Check if device has already been claimed. This may
|
|
* happen with driver loading, device discovery/registration,
|
|
* and deferred probe processing happens all at once with
|
|
* multiple threads.
|
|
*/
|
|
if (dev->driver)
|
|
return -EBUSY;
|
|
|
|
ret = driver_match_device(drv, dev);
|
|
if (ret == 0) {
|
|
/* no match */
|
|
return 0;
|
|
} else if (ret == -EPROBE_DEFER) {
|
|
dev_dbg(dev, "Device match requests probe deferral\n");
|
|
driver_deferred_probe_add(dev);
|
|
} else if (ret < 0) {
|
|
dev_dbg(dev, "Bus failed to match device: %d", ret);
|
|
return ret;
|
|
} /* ret > 0 means positive match */
|
|
|
|
async_allowed = driver_allows_async_probing(drv);
|
|
|
|
if (async_allowed)
|
|
data->have_async = true;
|
|
|
|
if (data->check_async && async_allowed != data->want_async)
|
|
return 0;
|
|
|
|
return driver_probe_device(drv, dev);
|
|
}
|
|
|
|
static void __device_attach_async_helper(void *_dev, async_cookie_t cookie)
|
|
{
|
|
struct device *dev = _dev;
|
|
struct device_attach_data data = {
|
|
.dev = dev,
|
|
.check_async = true,
|
|
.want_async = true,
|
|
};
|
|
|
|
device_lock(dev);
|
|
|
|
if (dev->parent)
|
|
pm_runtime_get_sync(dev->parent);
|
|
|
|
bus_for_each_drv(dev->bus, NULL, &data, __device_attach_driver);
|
|
dev_dbg(dev, "async probe completed\n");
|
|
|
|
pm_request_idle(dev);
|
|
|
|
if (dev->parent)
|
|
pm_runtime_put(dev->parent);
|
|
|
|
device_unlock(dev);
|
|
|
|
put_device(dev);
|
|
}
|
|
|
|
static int __device_attach(struct device *dev, bool allow_async)
|
|
{
|
|
int ret = 0;
|
|
|
|
device_lock(dev);
|
|
if (dev->driver) {
|
|
if (device_is_bound(dev)) {
|
|
ret = 1;
|
|
goto out_unlock;
|
|
}
|
|
ret = device_bind_driver(dev);
|
|
if (ret == 0)
|
|
ret = 1;
|
|
else {
|
|
dev->driver = NULL;
|
|
ret = 0;
|
|
}
|
|
} else {
|
|
struct device_attach_data data = {
|
|
.dev = dev,
|
|
.check_async = allow_async,
|
|
.want_async = false,
|
|
};
|
|
|
|
if (dev->parent)
|
|
pm_runtime_get_sync(dev->parent);
|
|
|
|
ret = bus_for_each_drv(dev->bus, NULL, &data,
|
|
__device_attach_driver);
|
|
if (!ret && allow_async && data.have_async) {
|
|
/*
|
|
* If we could not find appropriate driver
|
|
* synchronously and we are allowed to do
|
|
* async probes and there are drivers that
|
|
* want to probe asynchronously, we'll
|
|
* try them.
|
|
*/
|
|
dev_dbg(dev, "scheduling asynchronous probe\n");
|
|
get_device(dev);
|
|
async_schedule(__device_attach_async_helper, dev);
|
|
} else {
|
|
pm_request_idle(dev);
|
|
}
|
|
|
|
if (dev->parent)
|
|
pm_runtime_put(dev->parent);
|
|
}
|
|
out_unlock:
|
|
device_unlock(dev);
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* device_attach - try to attach device to a driver.
|
|
* @dev: device.
|
|
*
|
|
* Walk the list of drivers that the bus has and call
|
|
* driver_probe_device() for each pair. If a compatible
|
|
* pair is found, break out and return.
|
|
*
|
|
* Returns 1 if the device was bound to a driver;
|
|
* 0 if no matching driver was found;
|
|
* -ENODEV if the device is not registered.
|
|
*
|
|
* When called for a USB interface, @dev->parent lock must be held.
|
|
*/
|
|
int device_attach(struct device *dev)
|
|
{
|
|
return __device_attach(dev, false);
|
|
}
|
|
EXPORT_SYMBOL_GPL(device_attach);
|
|
|
|
void device_initial_probe(struct device *dev)
|
|
{
|
|
__device_attach(dev, true);
|
|
}
|
|
|
|
static int __driver_attach(struct device *dev, void *data)
|
|
{
|
|
struct device_driver *drv = data;
|
|
int ret;
|
|
|
|
/*
|
|
* Lock device and try to bind to it. We drop the error
|
|
* here and always return 0, because we need to keep trying
|
|
* to bind to devices and some drivers will return an error
|
|
* simply if it didn't support the device.
|
|
*
|
|
* driver_probe_device() will spit a warning if there
|
|
* is an error.
|
|
*/
|
|
|
|
ret = driver_match_device(drv, dev);
|
|
if (ret == 0) {
|
|
/* no match */
|
|
return 0;
|
|
} else if (ret == -EPROBE_DEFER) {
|
|
dev_dbg(dev, "Device match requests probe deferral\n");
|
|
driver_deferred_probe_add(dev);
|
|
} else if (ret < 0) {
|
|
dev_dbg(dev, "Bus failed to match device: %d", ret);
|
|
return ret;
|
|
} /* ret > 0 means positive match */
|
|
|
|
if (dev->parent && dev->bus->need_parent_lock)
|
|
device_lock(dev->parent);
|
|
device_lock(dev);
|
|
if (!dev->driver)
|
|
driver_probe_device(drv, dev);
|
|
device_unlock(dev);
|
|
if (dev->parent && dev->bus->need_parent_lock)
|
|
device_unlock(dev->parent);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* driver_attach - try to bind driver to devices.
|
|
* @drv: driver.
|
|
*
|
|
* Walk the list of devices that the bus has on it and try to
|
|
* match the driver with each one. If driver_probe_device()
|
|
* returns 0 and the @dev->driver is set, we've found a
|
|
* compatible pair.
|
|
*/
|
|
int driver_attach(struct device_driver *drv)
|
|
{
|
|
return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach);
|
|
}
|
|
EXPORT_SYMBOL_GPL(driver_attach);
|
|
|
|
/*
|
|
* __device_release_driver() must be called with @dev lock held.
|
|
* When called for a USB interface, @dev->parent lock must be held as well.
|
|
*/
|
|
static void __device_release_driver(struct device *dev, struct device *parent)
|
|
{
|
|
struct device_driver *drv;
|
|
|
|
drv = dev->driver;
|
|
if (drv) {
|
|
if (driver_allows_async_probing(drv))
|
|
async_synchronize_full();
|
|
|
|
while (device_links_busy(dev)) {
|
|
device_unlock(dev);
|
|
if (parent)
|
|
device_unlock(parent);
|
|
|
|
device_links_unbind_consumers(dev);
|
|
if (parent)
|
|
device_lock(parent);
|
|
|
|
device_lock(dev);
|
|
/*
|
|
* A concurrent invocation of the same function might
|
|
* have released the driver successfully while this one
|
|
* was waiting, so check for that.
|
|
*/
|
|
if (dev->driver != drv)
|
|
return;
|
|
}
|
|
|
|
pm_runtime_get_sync(dev);
|
|
pm_runtime_clean_up_links(dev);
|
|
|
|
driver_sysfs_remove(dev);
|
|
|
|
if (dev->bus)
|
|
blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
|
|
BUS_NOTIFY_UNBIND_DRIVER,
|
|
dev);
|
|
|
|
pm_runtime_put_sync(dev);
|
|
|
|
if (dev->bus && dev->bus->remove)
|
|
dev->bus->remove(dev);
|
|
else if (drv->remove)
|
|
drv->remove(dev);
|
|
|
|
device_links_driver_cleanup(dev);
|
|
arch_teardown_dma_ops(dev);
|
|
|
|
devres_release_all(dev);
|
|
dev->driver = NULL;
|
|
dev_set_drvdata(dev, NULL);
|
|
if (dev->pm_domain && dev->pm_domain->dismiss)
|
|
dev->pm_domain->dismiss(dev);
|
|
pm_runtime_reinit(dev);
|
|
dev_pm_set_driver_flags(dev, 0);
|
|
|
|
klist_remove(&dev->p->knode_driver);
|
|
device_pm_check_callbacks(dev);
|
|
if (dev->bus)
|
|
blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
|
|
BUS_NOTIFY_UNBOUND_DRIVER,
|
|
dev);
|
|
|
|
kobject_uevent(&dev->kobj, KOBJ_UNBIND);
|
|
}
|
|
}
|
|
|
|
void device_release_driver_internal(struct device *dev,
|
|
struct device_driver *drv,
|
|
struct device *parent)
|
|
{
|
|
if (parent && dev->bus->need_parent_lock)
|
|
device_lock(parent);
|
|
|
|
device_lock(dev);
|
|
if (!drv || drv == dev->driver)
|
|
__device_release_driver(dev, parent);
|
|
|
|
device_unlock(dev);
|
|
if (parent && dev->bus->need_parent_lock)
|
|
device_unlock(parent);
|
|
}
|
|
|
|
/**
|
|
* device_release_driver - manually detach device from driver.
|
|
* @dev: device.
|
|
*
|
|
* Manually detach device from driver.
|
|
* When called for a USB interface, @dev->parent lock must be held.
|
|
*
|
|
* If this function is to be called with @dev->parent lock held, ensure that
|
|
* the device's consumers are unbound in advance or that their locks can be
|
|
* acquired under the @dev->parent lock.
|
|
*/
|
|
void device_release_driver(struct device *dev)
|
|
{
|
|
/*
|
|
* If anyone calls device_release_driver() recursively from
|
|
* within their ->remove callback for the same device, they
|
|
* will deadlock right here.
|
|
*/
|
|
device_release_driver_internal(dev, NULL, NULL);
|
|
}
|
|
EXPORT_SYMBOL_GPL(device_release_driver);
|
|
|
|
/**
|
|
* driver_detach - detach driver from all devices it controls.
|
|
* @drv: driver.
|
|
*/
|
|
void driver_detach(struct device_driver *drv)
|
|
{
|
|
struct device_private *dev_prv;
|
|
struct device *dev;
|
|
|
|
for (;;) {
|
|
spin_lock(&drv->p->klist_devices.k_lock);
|
|
if (list_empty(&drv->p->klist_devices.k_list)) {
|
|
spin_unlock(&drv->p->klist_devices.k_lock);
|
|
break;
|
|
}
|
|
dev_prv = list_entry(drv->p->klist_devices.k_list.prev,
|
|
struct device_private,
|
|
knode_driver.n_node);
|
|
dev = dev_prv->device;
|
|
get_device(dev);
|
|
spin_unlock(&drv->p->klist_devices.k_lock);
|
|
device_release_driver_internal(dev, drv, dev->parent);
|
|
put_device(dev);
|
|
}
|
|
}
|