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1278 lines
34 KiB
1278 lines
34 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
/* |
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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 <[email protected]> |
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* Copyright (c) 2007-2009 Novell Inc. |
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*/ |
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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-map-ops.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 <linux/slab.h> |
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|
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#include "base.h" |
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#include "power/power.h" |
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|
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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 bool initcalls_done; |
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|
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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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/* |
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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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static void __device_set_deferred_probe_reason(const struct device *dev, char *reason) |
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{ |
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kfree(dev->p->deferred_probe_reason); |
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dev->p->deferred_probe_reason = reason; |
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} |
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|
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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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|
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get_device(dev); |
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|
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__device_set_deferred_probe_reason(dev, NULL); |
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|
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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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/* |
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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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|
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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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|
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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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|
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void driver_deferred_probe_add(struct device *dev) |
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{ |
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if (!dev->can_match) |
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return; |
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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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|
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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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__device_set_deferred_probe_reason(dev, NULL); |
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} |
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mutex_unlock(&deferred_probe_mutex); |
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} |
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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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/* |
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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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/* |
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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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queue_work(system_unbound_wq, &deferred_probe_work); |
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} |
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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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/** |
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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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/** |
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* device_set_deferred_probe_reason() - Set defer probe reason message for device |
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* @dev: the pointer to the struct device |
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* @vaf: the pointer to va_format structure with message |
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*/ |
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void device_set_deferred_probe_reason(const struct device *dev, struct va_format *vaf) |
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{ |
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const char *drv = dev_driver_string(dev); |
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char *reason; |
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|
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mutex_lock(&deferred_probe_mutex); |
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|
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reason = kasprintf(GFP_KERNEL, "%s: %pV", drv, vaf); |
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__device_set_deferred_probe_reason(dev, reason); |
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|
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mutex_unlock(&deferred_probe_mutex); |
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} |
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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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|
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mutex_lock(&deferred_probe_mutex); |
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|
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list_for_each_entry(curr, &deferred_probe_pending_list, deferred_probe) |
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seq_printf(s, "%s\t%s", dev_name(curr->device), |
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curr->device->p->deferred_probe_reason ?: "\n"); |
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mutex_unlock(&deferred_probe_mutex); |
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|
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return 0; |
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} |
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DEFINE_SHOW_ATTRIBUTE(deferred_devs); |
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|
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int driver_deferred_probe_timeout; |
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EXPORT_SYMBOL_GPL(driver_deferred_probe_timeout); |
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static DECLARE_WAIT_QUEUE_HEAD(probe_timeout_waitqueue); |
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|
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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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|
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if (!kstrtoint(str, 10, &timeout)) |
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driver_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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|
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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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* Return: |
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* -ENODEV if initcalls have completed and modules are disabled. |
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* -ETIMEDOUT if the deferred probe timeout was set and has expired |
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* and modules are enabled. |
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* -EPROBE_DEFER in other cases. |
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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 (!IS_ENABLED(CONFIG_MODULES) && initcalls_done) { |
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dev_warn(dev, "ignoring dependency for device, assuming no driver\n"); |
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return -ENODEV; |
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} |
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|
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if (!driver_deferred_probe_timeout && initcalls_done) { |
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dev_warn(dev, "deferred probe timeout, ignoring dependency\n"); |
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return -ETIMEDOUT; |
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} |
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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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struct device_private *p; |
|
|
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fw_devlink_drivers_done(); |
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|
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driver_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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|
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mutex_lock(&deferred_probe_mutex); |
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list_for_each_entry(p, &deferred_probe_pending_list, deferred_probe) |
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dev_info(p->device, "deferred probe pending\n"); |
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mutex_unlock(&deferred_probe_mutex); |
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wake_up_all(&probe_timeout_waitqueue); |
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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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debugfs_create_file("devices_deferred", 0444, NULL, NULL, |
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&deferred_devs_fops); |
|
|
|
driver_deferred_probe_enable = true; |
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driver_deferred_probe_trigger(); |
|
/* Sort as many dependencies as possible before exiting initcalls */ |
|
flush_work(&deferred_probe_work); |
|
initcalls_done = true; |
|
|
|
if (!IS_ENABLED(CONFIG_MODULES)) |
|
fw_devlink_drivers_done(); |
|
|
|
/* |
|
* Trigger deferred probe again, this time we won't defer anything |
|
* that is optional |
|
*/ |
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driver_deferred_probe_trigger(); |
|
flush_work(&deferred_probe_work); |
|
|
|
if (driver_deferred_probe_timeout > 0) { |
|
schedule_delayed_work(&deferred_probe_timeout_work, |
|
driver_deferred_probe_timeout * HZ); |
|
} |
|
return 0; |
|
} |
|
late_initcall(deferred_probe_initcall); |
|
|
|
static void __exit deferred_probe_exit(void) |
|
{ |
|
debugfs_remove_recursive(debugfs_lookup("devices_deferred", NULL)); |
|
} |
|
__exitcall(deferred_probe_exit); |
|
|
|
/** |
|
* device_is_bound() - Check if device is bound to a driver |
|
* @dev: device to check |
|
* |
|
* Returns true if passed device has already finished probing successfully |
|
* against a driver. |
|
* |
|
* This function must be called with the device lock held. |
|
*/ |
|
bool device_is_bound(struct device *dev) |
|
{ |
|
return dev->p && klist_node_attached(&dev->p->knode_driver); |
|
} |
|
|
|
static void driver_bound(struct device *dev) |
|
{ |
|
if (device_is_bound(dev)) { |
|
pr_warn("%s: device %s already bound\n", |
|
__func__, kobject_name(&dev->kobj)); |
|
return; |
|
} |
|
|
|
pr_debug("driver: '%s': %s: bound to device '%s'\n", dev->driver->name, |
|
__func__, dev_name(dev)); |
|
|
|
klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices); |
|
device_links_driver_bound(dev); |
|
|
|
device_pm_check_callbacks(dev); |
|
|
|
/* |
|
* Make sure the device is no longer in one of the deferred lists and |
|
* kick off retrying all pending devices |
|
*/ |
|
driver_deferred_probe_del(dev); |
|
driver_deferred_probe_trigger(); |
|
|
|
if (dev->bus) |
|
blocking_notifier_call_chain(&dev->bus->p->bus_notifier, |
|
BUS_NOTIFY_BOUND_DRIVER, dev); |
|
|
|
kobject_uevent(&dev->kobj, KOBJ_BIND); |
|
} |
|
|
|
static ssize_t coredump_store(struct device *dev, struct device_attribute *attr, |
|
const char *buf, size_t count) |
|
{ |
|
device_lock(dev); |
|
dev->driver->coredump(dev); |
|
device_unlock(dev); |
|
|
|
return count; |
|
} |
|
static DEVICE_ATTR_WO(coredump); |
|
|
|
static int driver_sysfs_add(struct device *dev) |
|
{ |
|
int ret; |
|
|
|
if (dev->bus) |
|
blocking_notifier_call_chain(&dev->bus->p->bus_notifier, |
|
BUS_NOTIFY_BIND_DRIVER, dev); |
|
|
|
ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj, |
|
kobject_name(&dev->kobj)); |
|
if (ret) |
|
goto fail; |
|
|
|
ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj, |
|
"driver"); |
|
if (ret) |
|
goto rm_dev; |
|
|
|
if (!IS_ENABLED(CONFIG_DEV_COREDUMP) || !dev->driver->coredump) |
|
return 0; |
|
|
|
ret = device_create_file(dev, &dev_attr_coredump); |
|
if (!ret) |
|
return 0; |
|
|
|
sysfs_remove_link(&dev->kobj, "driver"); |
|
|
|
rm_dev: |
|
sysfs_remove_link(&dev->driver->p->kobj, |
|
kobject_name(&dev->kobj)); |
|
|
|
fail: |
|
return ret; |
|
} |
|
|
|
static void driver_sysfs_remove(struct device *dev) |
|
{ |
|
struct device_driver *drv = dev->driver; |
|
|
|
if (drv) { |
|
if (drv->coredump) |
|
device_remove_file(dev, &dev_attr_coredump); |
|
sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj)); |
|
sysfs_remove_link(&dev->kobj, "driver"); |
|
} |
|
} |
|
|
|
/** |
|
* 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. |
|
* Please verify that is 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) { |
|
device_links_force_bind(dev); |
|
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 ssize_t state_synced_show(struct device *dev, |
|
struct device_attribute *attr, char *buf) |
|
{ |
|
bool val; |
|
|
|
device_lock(dev); |
|
val = dev->state_synced; |
|
device_unlock(dev); |
|
|
|
return sysfs_emit(buf, "%u\n", val); |
|
} |
|
static DEVICE_ATTR_RO(state_synced); |
|
|
|
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)); |
|
if (!list_empty(&dev->devres_head)) { |
|
dev_crit(dev, "Resources present before probing\n"); |
|
ret = -EBUSY; |
|
goto done; |
|
} |
|
|
|
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)) { |
|
pr_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 (device_add_groups(dev, drv->dev_groups)) { |
|
dev_err(dev, "device_add_groups() failed\n"); |
|
goto dev_groups_failed; |
|
} |
|
|
|
if (dev_has_sync_state(dev) && |
|
device_create_file(dev, &dev_attr_state_synced)) { |
|
dev_err(dev, "state_synced sysfs add failed\n"); |
|
goto dev_sysfs_state_synced_failed; |
|
} |
|
|
|
if (test_remove) { |
|
test_remove = false; |
|
|
|
device_remove_file(dev, &dev_attr_state_synced); |
|
device_remove_groups(dev, drv->dev_groups); |
|
|
|
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; |
|
|
|
dev_sysfs_state_synced_failed: |
|
device_remove_groups(dev, drv->dev_groups); |
|
dev_groups_failed: |
|
if (dev->bus->remove) |
|
dev->bus->remove(dev); |
|
else if (drv->remove) |
|
drv->remove(dev); |
|
probe_failed: |
|
kfree(dev->dma_range_map); |
|
dev->dma_range_map = NULL; |
|
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 */ |
|
pr_warn("%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_all(&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, rettime; |
|
int ret; |
|
|
|
calltime = ktime_get(); |
|
ret = really_probe(dev, drv); |
|
rettime = ktime_get(); |
|
pr_debug("probe of %s returned %d after %lld usecs\n", |
|
dev_name(dev), ret, ktime_us_delta(rettime, calltime)); |
|
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) |
|
{ |
|
int local_probe_count = atomic_read(&probe_count); |
|
|
|
pr_debug("%s: probe_count = %d\n", __func__, local_probe_count); |
|
if (local_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 probe timeout */ |
|
wait_event(probe_timeout_waitqueue, !driver_deferred_probe_timeout); |
|
|
|
/* 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. |
|
*/ |
|
static int driver_probe_device(struct device_driver *drv, struct device *dev) |
|
{ |
|
int ret = 0; |
|
|
|
if (!device_is_registered(dev)) |
|
return -ENODEV; |
|
|
|
dev->can_match = true; |
|
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) |
|
pr_warn("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"); |
|
dev->can_match = true; |
|
driver_deferred_probe_add(dev); |
|
} else if (ret < 0) { |
|
dev_dbg(dev, "Bus failed to match device: %d\n", 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->p->dead) { |
|
goto out_unlock; |
|
} else 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"); |
|
dev->can_match = true; |
|
driver_deferred_probe_add(dev); |
|
} else if (ret < 0) { |
|
dev_dbg(dev, "Bus failed to match device: %d\n", 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) { |
|
pm_runtime_get_sync(dev); |
|
|
|
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) { |
|
pm_runtime_put(dev); |
|
return; |
|
} |
|
} |
|
|
|
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); |
|
|
|
device_remove_file(dev, &dev_attr_state_synced); |
|
device_remove_groups(dev, drv->dev_groups); |
|
|
|
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_last_entry(&drv->p->klist_devices.k_list, |
|
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); |
|
} |
|
}
|
|
|