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![Thierry Reding](/assets/img/avatar_default.png)
Some subsystems, such as pinctrl, allow continuing to defer probe indefinitely. This is useful for devices that depend on resources provided by devices that are only probed after the init stage. One example of this can be seen on Tegra, where the DPAUX hardware contains pinmuxing controls for pins that it shares with an I2C controller. The I2C controller is typically used for communication with a monitor over HDMI (DDC). However, other instances of the I2C controller are used to access system critical components, such as a PMIC. The I2C controller driver will therefore usually be a builtin driver, whereas the DPAUX driver is part of the display driver that is loaded from a module to avoid bloating the kernel image with all of the DRM/KMS subsystem. In this particular case the pins used by this I2C/DDC controller become accessible very late in the boot process. However, since the controller is only used in conjunction with display, that's not an issue. Unfortunately the driver core currently outputs a warning message when a device fails to get the pinctrl before the end of the init stage. That can be confusing for the user because it may sound like an unwanted error occurred, whereas it's really an expected and harmless situation. In order to eliminate this warning, this patch allows callers of the driver_deferred_probe_check_state() helper to specify that they want to continue deferring probe, regardless of whether we're past the init stage or not. All of the callers of that function are updated for the new signature, but only the pinctrl subsystem passes a true value in the new persist parameter if appropriate. Signed-off-by: Thierry Reding <treding@nvidia.com> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Link: https://lore.kernel.org/r/20190621151725.20414-1-thierry.reding@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1217 lines
32 KiB
C
1217 lines
32 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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/* Save the async probe drivers' name from kernel cmdline */
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#define ASYNC_DRV_NAMES_MAX_LEN 256
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static char async_probe_drv_names[ASYNC_DRV_NAMES_MAX_LEN];
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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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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/defer 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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int timeout;
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if (!kstrtoint(str, 10, &timeout))
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deferred_probe_timeout = timeout;
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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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static int __driver_deferred_probe_check_state(struct device *dev)
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{
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if (!initcalls_done)
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return -EPROBE_DEFER;
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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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return 0;
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}
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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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int ret;
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ret = __driver_deferred_probe_check_state(dev);
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if (ret < 0)
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return ret;
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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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/**
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* driver_deferred_probe_check_state_continue() - check deferred probe state
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* @dev: device to check
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*
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* Returns -ETIMEDOUT if deferred probe debug timeout has expired, or
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* -EPROBE_DEFER otherwise.
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*
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* Drivers or subsystems can opt-in to calling this function instead of
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* directly returning -EPROBE_DEFER.
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*
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* This is similar to driver_deferred_probe_check_state(), but it allows the
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* subsystem to keep deferring probe after built-in drivers have had a chance
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* to probe. One scenario where that is useful is if built-in drivers rely on
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* resources that are provided by modular drivers.
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*/
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int driver_deferred_probe_check_state_continue(struct device *dev)
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{
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int ret;
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ret = __driver_deferred_probe_check_state(dev);
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if (ret < 0)
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return ret;
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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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|
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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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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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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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fail:
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return ret;
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}
|
|
|
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static void driver_sysfs_remove(struct device *dev)
|
|
{
|
|
struct device_driver *drv = dev->driver;
|
|
|
|
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.
|
|
* @dev: device.
|
|
*
|
|
* Allow manual attachment of a driver to a device.
|
|
* Caller must have already set @dev->driver.
|
|
*
|
|
* 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.
|
|
*/
|
|
int device_bind_driver(struct device *dev)
|
|
{
|
|
int ret;
|
|
|
|
ret = driver_sysfs_add(dev);
|
|
if (!ret)
|
|
driver_bound(dev);
|
|
else if (dev->bus)
|
|
blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
|
|
BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
|
|
return ret;
|
|
}
|
|
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_block_probing() 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 probe_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:
|
|
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);
|
|
arch_teardown_dma_ops(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;
|
|
}
|
|
|
|
static inline bool cmdline_requested_async_probing(const char *drv_name)
|
|
{
|
|
return parse_option_str(async_probe_drv_names, drv_name);
|
|
}
|
|
|
|
/* The option format is "driver_async_probe=drv_name1,drv_name2,..." */
|
|
static int __init save_async_options(char *buf)
|
|
{
|
|
if (strlen(buf) >= ASYNC_DRV_NAMES_MAX_LEN)
|
|
printk(KERN_WARNING
|
|
"Too long list of driver names for 'driver_async_probe'!\n");
|
|
|
|
strlcpy(async_probe_drv_names, buf, ASYNC_DRV_NAMES_MAX_LEN);
|
|
return 0;
|
|
}
|
|
__setup("driver_async_probe=", save_async_options);
|
|
|
|
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 (cmdline_requested_async_probing(drv->name))
|
|
return true;
|
|
|
|
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;
|
|
|
|
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);
|
|
|
|
/*
|
|
* Check if device has already been removed or claimed. This may
|
|
* happen with driver loading, device discovery/registration,
|
|
* and deferred probe processing happens all at once with
|
|
* multiple threads.
|
|
*/
|
|
if (dev->p->dead || dev->driver)
|
|
goto out_unlock;
|
|
|
|
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);
|
|
out_unlock:
|
|
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_dev(__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);
|
|
}
|
|
|
|
/*
|
|
* __device_driver_lock - acquire locks needed to manipulate dev->drv
|
|
* @dev: Device we will update driver info for
|
|
* @parent: Parent device. Needed if the bus requires parent lock
|
|
*
|
|
* This function will take the required locks for manipulating dev->drv.
|
|
* Normally this will just be the @dev lock, but when called for a USB
|
|
* interface, @parent lock will be held as well.
|
|
*/
|
|
static void __device_driver_lock(struct device *dev, struct device *parent)
|
|
{
|
|
if (parent && dev->bus->need_parent_lock)
|
|
device_lock(parent);
|
|
device_lock(dev);
|
|
}
|
|
|
|
/*
|
|
* __device_driver_unlock - release locks needed to manipulate dev->drv
|
|
* @dev: Device we will update driver info for
|
|
* @parent: Parent device. Needed if the bus requires parent lock
|
|
*
|
|
* This function will release the required locks for manipulating dev->drv.
|
|
* Normally this will just be the the @dev lock, but when called for a
|
|
* USB interface, @parent lock will be released as well.
|
|
*/
|
|
static void __device_driver_unlock(struct device *dev, struct device *parent)
|
|
{
|
|
device_unlock(dev);
|
|
if (parent && dev->bus->need_parent_lock)
|
|
device_unlock(parent);
|
|
}
|
|
|
|
/**
|
|
* device_driver_attach - attach a specific driver to a specific device
|
|
* @drv: Driver to attach
|
|
* @dev: Device to attach it to
|
|
*
|
|
* Manually attach driver to a device. Will acquire both @dev lock and
|
|
* @dev->parent lock if needed.
|
|
*/
|
|
int device_driver_attach(struct device_driver *drv, struct device *dev)
|
|
{
|
|
int ret = 0;
|
|
|
|
__device_driver_lock(dev, dev->parent);
|
|
|
|
/*
|
|
* If device has been removed or someone has already successfully
|
|
* bound a driver before us just skip the driver probe call.
|
|
*/
|
|
if (!dev->p->dead && !dev->driver)
|
|
ret = driver_probe_device(drv, dev);
|
|
|
|
__device_driver_unlock(dev, dev->parent);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void __driver_attach_async_helper(void *_dev, async_cookie_t cookie)
|
|
{
|
|
struct device *dev = _dev;
|
|
struct device_driver *drv;
|
|
int ret = 0;
|
|
|
|
__device_driver_lock(dev, dev->parent);
|
|
|
|
drv = dev->p->async_driver;
|
|
|
|
/*
|
|
* If device has been removed or someone has already successfully
|
|
* bound a driver before us just skip the driver probe call.
|
|
*/
|
|
if (!dev->p->dead && !dev->driver)
|
|
ret = driver_probe_device(drv, dev);
|
|
|
|
__device_driver_unlock(dev, dev->parent);
|
|
|
|
dev_dbg(dev, "driver %s async attach completed: %d\n", drv->name, ret);
|
|
|
|
put_device(dev);
|
|
}
|
|
|
|
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 (driver_allows_async_probing(drv)) {
|
|
/*
|
|
* Instead of probing the device synchronously we will
|
|
* probe it asynchronously to allow for more parallelism.
|
|
*
|
|
* We only take the device lock here in order to guarantee
|
|
* that the dev->driver and async_driver fields are protected
|
|
*/
|
|
dev_dbg(dev, "probing driver %s asynchronously\n", drv->name);
|
|
device_lock(dev);
|
|
if (!dev->driver) {
|
|
get_device(dev);
|
|
dev->p->async_driver = drv;
|
|
async_schedule_dev(__driver_attach_async_helper, dev);
|
|
}
|
|
device_unlock(dev);
|
|
return 0;
|
|
}
|
|
|
|
device_driver_attach(drv, dev);
|
|
|
|
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) {
|
|
while (device_links_busy(dev)) {
|
|
__device_driver_unlock(dev, parent);
|
|
|
|
device_links_unbind_consumers(dev);
|
|
|
|
__device_driver_lock(dev, parent);
|
|
/*
|
|
* 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);
|
|
|
|
devres_release_all(dev);
|
|
arch_teardown_dma_ops(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)
|
|
{
|
|
__device_driver_lock(dev, parent);
|
|
|
|
if (!drv || drv == dev->driver)
|
|
__device_release_driver(dev, parent);
|
|
|
|
__device_driver_unlock(dev, 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);
|
|
|
|
/**
|
|
* device_driver_detach - detach driver from a specific device
|
|
* @dev: device to detach driver from
|
|
*
|
|
* Detach driver from device. Will acquire both @dev lock and @dev->parent
|
|
* lock if needed.
|
|
*/
|
|
void device_driver_detach(struct device *dev)
|
|
{
|
|
device_release_driver_internal(dev, NULL, dev->parent);
|
|
}
|
|
|
|
/**
|
|
* 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;
|
|
|
|
if (driver_allows_async_probing(drv))
|
|
async_synchronize_full();
|
|
|
|
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);
|
|
}
|
|
}
|