diff options
Diffstat (limited to 'drivers/base/dd.c')
| -rw-r--r-- | drivers/base/dd.c | 1155 |
1 files changed, 964 insertions, 191 deletions
diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 35fa36898916..349f31bedfa1 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0 /* * drivers/base/dd.c - The core device/driver interactions. * @@ -13,18 +14,21 @@ * Copyright (c) 2002-3 Open Source Development Labs * Copyright (c) 2007-2009 Greg Kroah-Hartman <gregkh@suse.de> * Copyright (c) 2007-2009 Novell Inc. - * - * This file is released under the GPLv2 */ +#include <linux/debugfs.h> #include <linux/device.h> #include <linux/delay.h> +#include <linux/dma-map-ops.h> +#include <linux/init.h> #include <linux/module.h> #include <linux/kthread.h> #include <linux/wait.h> #include <linux/async.h> +#include <linux/pm_domain.h> #include <linux/pm_runtime.h> #include <linux/pinctrl/devinfo.h> +#include <linux/slab.h> #include "base.h" #include "power/power.h" @@ -51,9 +55,28 @@ static DEFINE_MUTEX(deferred_probe_mutex); static LIST_HEAD(deferred_probe_pending_list); static LIST_HEAD(deferred_probe_active_list); -static struct workqueue_struct *deferred_wq; +static atomic_t deferred_trigger_count = ATOMIC_INIT(0); +static bool initcalls_done; -/** +/* Save the async probe drivers' name from kernel cmdline */ +#define ASYNC_DRV_NAMES_MAX_LEN 256 +static char async_probe_drv_names[ASYNC_DRV_NAMES_MAX_LEN]; +static bool async_probe_default; + +/* + * In some cases, like suspend to RAM or hibernation, It might be reasonable + * to prohibit probing of devices as it could be unsafe. + * Once defer_all_probes is true all drivers probes will be forcibly deferred. + */ +static bool defer_all_probes; + +static void __device_set_deferred_probe_reason(const struct device *dev, char *reason) +{ + kfree(dev->p->deferred_probe_reason); + dev->p->deferred_probe_reason = reason; +} + +/* * deferred_probe_work_func() - Retry probing devices in the active list. */ static void deferred_probe_work_func(struct work_struct *work) @@ -81,6 +104,8 @@ static void deferred_probe_work_func(struct work_struct *work) get_device(dev); + __device_set_deferred_probe_reason(dev, NULL); + /* * Drop the mutex while probing each device; the probe path may * manipulate the deferred list @@ -93,13 +118,10 @@ static void deferred_probe_work_func(struct work_struct *work) * the list is a good order for suspend but deferred * probe makes that very unsafe. */ - device_pm_lock(); - device_pm_move_last(dev); - device_pm_unlock(); + device_pm_move_to_tail(dev); dev_dbg(dev, "Retrying from deferred list\n"); bus_probe_device(dev); - mutex_lock(&deferred_probe_mutex); put_device(dev); @@ -108,8 +130,11 @@ static void deferred_probe_work_func(struct work_struct *work) } static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func); -static void driver_deferred_probe_add(struct device *dev) +void driver_deferred_probe_add(struct device *dev) { + if (!dev->can_match) + return; + mutex_lock(&deferred_probe_mutex); if (list_empty(&dev->p->deferred_probe)) { dev_dbg(dev, "Added to deferred list\n"); @@ -124,19 +149,31 @@ void driver_deferred_probe_del(struct device *dev) if (!list_empty(&dev->p->deferred_probe)) { dev_dbg(dev, "Removed from deferred list\n"); list_del_init(&dev->p->deferred_probe); + __device_set_deferred_probe_reason(dev, NULL); } mutex_unlock(&deferred_probe_mutex); } -static bool driver_deferred_probe_enable = false; +static bool driver_deferred_probe_enable; /** * driver_deferred_probe_trigger() - Kick off re-probing deferred devices * * This functions moves all devices from the pending list to the active * list and schedules the deferred probe workqueue to process them. It * should be called anytime a driver is successfully bound to a device. + * + * Note, there is a race condition in multi-threaded probe. In the case where + * more than one device is probing at the same time, it is possible for one + * probe to complete successfully while another is about to defer. If the second + * depends on the first, then it will get put on the pending list after the + * trigger event has already occurred and will be stuck there. + * + * The atomic 'deferred_trigger_count' is used to determine if a successful + * trigger has occurred in the midst of probing a driver. If the trigger count + * changes in the midst of a probe, then deferred processing should be triggered + * again. */ -static void driver_deferred_probe_trigger(void) +void driver_deferred_probe_trigger(void) { if (!driver_deferred_probe_enable) return; @@ -147,6 +184,7 @@ static void driver_deferred_probe_trigger(void) * into the active list so they can be retried by the workqueue */ mutex_lock(&deferred_probe_mutex); + atomic_inc(&deferred_trigger_count); list_splice_tail_init(&deferred_probe_pending_list, &deferred_probe_active_list); mutex_unlock(&deferred_probe_mutex); @@ -155,7 +193,146 @@ static void driver_deferred_probe_trigger(void) * Kick the re-probe thread. It may already be scheduled, but it is * safe to kick it again. */ - queue_work(deferred_wq, &deferred_probe_work); + queue_work(system_dfl_wq, &deferred_probe_work); +} + +/** + * device_block_probing() - Block/defer device's probes + * + * It will disable probing of devices and defer their probes instead. + */ +void device_block_probing(void) +{ + defer_all_probes = true; + /* sync with probes to avoid races. */ + wait_for_device_probe(); +} + +/** + * device_unblock_probing() - Unblock/enable device's probes + * + * It will restore normal behavior and trigger re-probing of deferred + * devices. + */ +void device_unblock_probing(void) +{ + defer_all_probes = false; + driver_deferred_probe_trigger(); +} + +/** + * device_set_deferred_probe_reason() - Set defer probe reason message for device + * @dev: the pointer to the struct device + * @vaf: the pointer to va_format structure with message + */ +void device_set_deferred_probe_reason(const struct device *dev, struct va_format *vaf) +{ + const char *drv = dev_driver_string(dev); + char *reason; + + mutex_lock(&deferred_probe_mutex); + + reason = kasprintf(GFP_KERNEL, "%s: %pV", drv, vaf); + __device_set_deferred_probe_reason(dev, reason); + + mutex_unlock(&deferred_probe_mutex); +} + +/* + * deferred_devs_show() - Show the devices in the deferred probe pending list. + */ +static int deferred_devs_show(struct seq_file *s, void *data) +{ + struct device_private *curr; + + mutex_lock(&deferred_probe_mutex); + + list_for_each_entry(curr, &deferred_probe_pending_list, deferred_probe) + seq_printf(s, "%s\t%s", dev_name(curr->device), + curr->deferred_probe_reason ?: "\n"); + + mutex_unlock(&deferred_probe_mutex); + + return 0; +} +DEFINE_SHOW_ATTRIBUTE(deferred_devs); + +#ifdef CONFIG_MODULES +static int driver_deferred_probe_timeout = 10; +#else +static int driver_deferred_probe_timeout; +#endif + +static int __init deferred_probe_timeout_setup(char *str) +{ + int timeout; + + if (!kstrtoint(str, 10, &timeout)) + driver_deferred_probe_timeout = timeout; + return 1; +} +__setup("deferred_probe_timeout=", deferred_probe_timeout_setup); + +/** + * driver_deferred_probe_check_state() - Check deferred probe state + * @dev: device to check + * + * Return: + * * -ENODEV if initcalls have completed and modules are disabled. + * * -ETIMEDOUT if the deferred probe timeout was set and has expired + * and modules are enabled. + * * -EPROBE_DEFER in other cases. + * + * Drivers or subsystems can opt-in to calling this function instead of directly + * returning -EPROBE_DEFER. + */ +int driver_deferred_probe_check_state(struct device *dev) +{ + if (!IS_ENABLED(CONFIG_MODULES) && initcalls_done) { + dev_warn(dev, "ignoring dependency for device, assuming no driver\n"); + return -ENODEV; + } + + if (!driver_deferred_probe_timeout && initcalls_done) { + dev_warn(dev, "deferred probe timeout, ignoring dependency\n"); + return -ETIMEDOUT; + } + + return -EPROBE_DEFER; +} +EXPORT_SYMBOL_GPL(driver_deferred_probe_check_state); + +static void deferred_probe_timeout_work_func(struct work_struct *work) +{ + struct device_private *p; + + fw_devlink_drivers_done(); + + driver_deferred_probe_timeout = 0; + driver_deferred_probe_trigger(); + flush_work(&deferred_probe_work); + + mutex_lock(&deferred_probe_mutex); + list_for_each_entry(p, &deferred_probe_pending_list, deferred_probe) + dev_warn(p->device, "deferred probe pending: %s", p->deferred_probe_reason ?: "(reason unknown)\n"); + mutex_unlock(&deferred_probe_mutex); + + fw_devlink_probing_done(); +} +static DECLARE_DELAYED_WORK(deferred_probe_timeout_work, deferred_probe_timeout_work_func); + +void deferred_probe_extend_timeout(void) +{ + /* + * If the work hasn't been queued yet or if the work expired, don't + * start a new one. + */ + if (cancel_delayed_work(&deferred_probe_timeout_work)) { + schedule_delayed_work(&deferred_probe_timeout_work, + driver_deferred_probe_timeout * HZ); + pr_debug("Extended deferred probe timeout by %d secs\n", + driver_deferred_probe_timeout); + } } /** @@ -167,30 +344,72 @@ static void driver_deferred_probe_trigger(void) */ static int deferred_probe_initcall(void) { - deferred_wq = create_singlethread_workqueue("deferwq"); - if (WARN_ON(!deferred_wq)) - return -ENOMEM; + debugfs_create_file("devices_deferred", 0444, NULL, NULL, + &deferred_devs_fops); driver_deferred_probe_enable = true; driver_deferred_probe_trigger(); /* Sort as many dependencies as possible before exiting initcalls */ - flush_workqueue(deferred_wq); + 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 + */ + 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); + } + + if (!IS_ENABLED(CONFIG_MODULES)) + fw_devlink_probing_done(); + return 0; } late_initcall(deferred_probe_initcall); +static void __exit deferred_probe_exit(void) +{ + debugfs_lookup_and_remove("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); +} +EXPORT_SYMBOL_GPL(device_is_bound); + static void driver_bound(struct device *dev) { - if (klist_node_attached(&dev->p->knode_driver)) { - printk(KERN_WARNING "%s: device %s already bound\n", - __func__, kobject_name(&dev->kobj)); + if (device_is_bound(dev)) { + dev_warn(dev, "%s: device already bound\n", __func__); return; } - pr_debug("driver: '%s': %s: bound to device '%s'\n", dev_name(dev), - __func__, dev->driver->name); + dev_dbg(dev, "driver: '%s': %s: bound to device\n", dev->driver->name, + __func__); 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 @@ -199,28 +418,51 @@ static void driver_bound(struct device *dev) 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); + bus_notify(dev, BUS_NOTIFY_BOUND_DRIVER); + 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); + bus_notify(dev, BUS_NOTIFY_BIND_DRIVER); 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)); - if (ret == 0) { - ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj, - "driver"); - if (ret) - sysfs_remove_link(&dev->driver->p->kobj, - kobject_name(&dev->kobj)); - } + +fail: return ret; } @@ -229,6 +471,8 @@ 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"); } @@ -241,20 +485,25 @@ static void driver_sysfs_remove(struct device *dev) * 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.) + * 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. + * + * Callers should prefer to use device_driver_attach() instead. */ int device_bind_driver(struct device *dev) { int ret; ret = driver_sysfs_add(dev); - if (!ret) + if (!ret) { + device_links_force_bind(dev); driver_bound(dev); + } + else + bus_notify(dev, BUS_NOTIFY_DRIVER_NOT_BOUND); return ret; } EXPORT_SYMBOL_GPL(device_bind_driver); @@ -262,71 +511,240 @@ EXPORT_SYMBOL_GPL(device_bind_driver); static atomic_t probe_count = ATOMIC_INIT(0); static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue); -static int really_probe(struct device *dev, struct device_driver *drv) +static ssize_t state_synced_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) { int ret = 0; - 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)); + if (strcmp("1", buf)) + return -EINVAL; + + device_lock(dev); + if (!dev->state_synced) { + dev->state_synced = true; + dev_sync_state(dev); + } else { + ret = -EINVAL; + } + device_unlock(dev); + + return ret ? ret : count; +} + +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_RW(state_synced); + +static void device_unbind_cleanup(struct device *dev) +{ + devres_release_all(dev); + arch_teardown_dma_ops(dev); + kfree(dev->dma_range_map); + dev->dma_range_map = NULL; + device_set_driver(dev, NULL); + dev_set_drvdata(dev, NULL); + dev_pm_domain_detach(dev, dev->power.detach_power_off); + if (dev->pm_domain && dev->pm_domain->dismiss) + dev->pm_domain->dismiss(dev); + pm_runtime_reinit(dev); + dev_pm_set_driver_flags(dev, 0); +} + +static void device_remove(struct device *dev) +{ + device_remove_file(dev, &dev_attr_state_synced); + device_remove_groups(dev, dev->driver->dev_groups); + + if (dev->bus && dev->bus->remove) + dev->bus->remove(dev); + else if (dev->driver->remove) + dev->driver->remove(dev); +} + +static int call_driver_probe(struct device *dev, const struct device_driver *drv) +{ + int ret = 0; + + if (dev->bus->probe) + ret = dev->bus->probe(dev); + else if (drv->probe) + ret = drv->probe(dev); + + switch (ret) { + case 0: + break; + case -EPROBE_DEFER: + /* Driver requested deferred probing */ + dev_dbg(dev, "Driver %s requests probe deferral\n", drv->name); + break; + case -ENODEV: + case -ENXIO: + dev_dbg(dev, "probe with driver %s rejects match %d\n", + drv->name, ret); + break; + default: + /* driver matched but the probe failed */ + dev_err(dev, "probe with driver %s failed with error %d\n", + drv->name, ret); + break; + } + + return ret; +} + +static int really_probe(struct device *dev, const struct device_driver *drv) +{ + bool test_remove = IS_ENABLED(CONFIG_DEBUG_TEST_DRIVER_REMOVE) && + !drv->suppress_bind_attrs; + int ret, link_ret; + + 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); + return -EPROBE_DEFER; + } - dev->driver = drv; + link_ret = device_links_check_suppliers(dev); + if (link_ret == -EPROBE_DEFER) + return link_ret; + + dev_dbg(dev, "bus: '%s': %s: probing driver %s with device\n", + drv->bus->name, __func__, drv->name); + if (!list_empty(&dev->devres_head)) { + dev_crit(dev, "Resources present before probing\n"); + ret = -EBUSY; + goto done; + } + +re_probe: + device_set_driver(dev, drv); /* If using pinctrl, bind pins now before probing */ ret = pinctrl_bind_pins(dev); if (ret) - goto probe_failed; + goto pinctrl_bind_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->bus->dma_configure) { + ret = dev->bus->dma_configure(dev); + if (ret) + goto pinctrl_bind_failed; } - if (dev->bus->probe) { - ret = dev->bus->probe(dev); - if (ret) - goto probe_failed; - } else if (drv->probe) { - ret = drv->probe(dev); + ret = driver_sysfs_add(dev); + if (ret) { + dev_err(dev, "%s: driver_sysfs_add failed\n", __func__); + goto sysfs_failed; + } + + if (dev->pm_domain && dev->pm_domain->activate) { + ret = dev->pm_domain->activate(dev); if (ret) goto probe_failed; } + ret = call_driver_probe(dev, drv); + if (ret) { + /* + * If fw_devlink_best_effort is active (denoted by -EAGAIN), the + * device might actually probe properly once some of its missing + * suppliers have probed. So, treat this as if the driver + * returned -EPROBE_DEFER. + */ + if (link_ret == -EAGAIN) + ret = -EPROBE_DEFER; + + /* + * Return probe errors as positive values so that the callers + * can distinguish them from other errors. + */ + ret = -ret; + goto probe_failed; + } + + ret = device_add_groups(dev, drv->dev_groups); + if (ret) { + dev_err(dev, "device_add_groups() failed\n"); + goto dev_groups_failed; + } + + if (dev_has_sync_state(dev)) { + ret = device_create_file(dev, &dev_attr_state_synced); + if (ret) { + dev_err(dev, "state_synced sysfs add failed\n"); + goto dev_sysfs_state_synced_failed; + } + } + + if (test_remove) { + test_remove = false; + + device_remove(dev); + driver_sysfs_remove(dev); + if (dev->bus && dev->bus->dma_cleanup) + dev->bus->dma_cleanup(dev); + device_unbind_cleanup(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); + dev_dbg(dev, "bus: '%s': %s: bound device to driver %s\n", + drv->bus->name, __func__, drv->name); goto done; +dev_sysfs_state_synced_failed: +dev_groups_failed: + device_remove(dev); probe_failed: - devres_release_all(dev); driver_sysfs_remove(dev); - dev->driver = NULL; - dev_set_drvdata(dev, NULL); +sysfs_failed: + bus_notify(dev, BUS_NOTIFY_DRIVER_NOT_BOUND); + if (dev->bus && dev->bus->dma_cleanup) + dev->bus->dma_cleanup(dev); +pinctrl_bind_failed: + device_links_no_driver(dev); + device_unbind_cleanup(dev); +done: + return ret; +} - if (ret == -EPROBE_DEFER) { - /* Driver requested deferred probing */ - dev_info(dev, "Driver %s requests probe deferral\n", drv->name); - driver_deferred_probe_add(dev); - } else if (ret != -ENODEV && ret != -ENXIO) { - /* driver matched but the probe failed */ - printk(KERN_WARNING - "%s: probe of %s failed with error %d\n", - drv->name, dev_name(dev), ret); - } else { - pr_debug("%s: probe of %s rejects match %d\n", - drv->name, dev_name(dev), ret); - } +/* + * For initcall_debug, show the driver probe time. + */ +static int really_probe_debug(struct device *dev, const struct device_driver *drv) +{ + ktime_t calltime, rettime; + int ret; + + calltime = ktime_get(); + ret = really_probe(dev, drv); + rettime = ktime_get(); /* - * Ignore errors returned by ->probe so that the next driver can try - * its luck. + * Don't change this to pr_debug() because that requires + * CONFIG_DYNAMIC_DEBUG and we want a simple 'initcall_debug' on the + * kernel commandline to print this all the time at the debug level. */ - ret = 0; -done: - atomic_dec(&probe_count); - wake_up(&probe_waitqueue); + printk(KERN_DEBUG "probe of %s returned %d after %lld usecs\n", + dev_name(dev), ret, ktime_us_delta(rettime, calltime)); return ret; } @@ -336,13 +754,12 @@ done: * * Should somehow figure out how to use a semaphore, not an atomic variable... */ -int driver_probe_done(void) +bool __init 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; + int local_probe_count = atomic_read(&probe_count); + + pr_debug("%s: probe_count = %d\n", __func__, local_probe_count); + return !local_probe_count; } /** @@ -351,48 +768,291 @@ int driver_probe_done(void) */ 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); +static int __driver_probe_device(const struct device_driver *drv, struct device *dev) +{ + int ret = 0; + + if (dev->p->dead || !device_is_registered(dev)) + return -ENODEV; + if (dev->driver) + return -EBUSY; + + dev->can_match = true; + dev_dbg(dev, "bus: '%s': %s: matched device with driver %s\n", + drv->bus->name, __func__, 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; +} + /** * 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 returns -ENODEV if the device is not registered, -EBUSY if it + * already has a driver, 0 if the device is bound successfully and a positive + * (inverted) error code for failures from the ->probe method. * * 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) +static int driver_probe_device(const struct device_driver *drv, struct device *dev) { - int ret = 0; + int trigger_count = atomic_read(&deferred_trigger_count); + int ret; - if (!device_is_registered(dev)) - return -ENODEV; + atomic_inc(&probe_count); + ret = __driver_probe_device(drv, dev); + if (ret == -EPROBE_DEFER || ret == EPROBE_DEFER) { + driver_deferred_probe_add(dev); + + /* + * Did a trigger occur while probing? Need to re-trigger if yes + */ + if (trigger_count != atomic_read(&deferred_trigger_count) && + !defer_all_probes) + driver_deferred_probe_trigger(); + } + atomic_dec(&probe_count); + wake_up_all(&probe_waitqueue); + return ret; +} + +static inline bool cmdline_requested_async_probing(const char *drv_name) +{ + bool async_drv; - pr_debug("bus: '%s': %s: matched device %s with driver %s\n", - drv->bus->name, __func__, dev_name(dev), drv->name); + async_drv = parse_option_str(async_probe_drv_names, drv_name); - pm_runtime_barrier(dev); - ret = really_probe(dev, drv); - pm_request_idle(dev); + return (async_probe_default != async_drv); +} - return ret; +/* 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"); + + strscpy(async_probe_drv_names, buf, ASYNC_DRV_NAMES_MAX_LEN); + async_probe_default = parse_option_str(async_probe_drv_names, "*"); + + return 1; +} +__setup("driver_async_probe=", save_async_options); + +static bool driver_allows_async_probing(const 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; + } } -static int __device_attach(struct device_driver *drv, void *data) +struct device_attach_data { + struct device *dev; + + /* + * Indicates whether we 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 *dev = 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); + /* + * Device can't match with a driver right now, so don't attempt + * to match or bind with other drivers on the bus. + */ + return ret; + } else if (ret < 0) { + dev_dbg(dev, "Bus failed to match device: %d\n", ret); + return ret; + } /* ret > 0 means positive match */ - if (!driver_match_device(drv, dev)) + 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); + /* + * Ignore errors returned by ->probe so that the next driver can try + * its luck. + */ + ret = driver_probe_device(drv, dev); + if (ret < 0) + return ret; + return ret == 0; +} + +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; + bool async = false; + + 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 { + device_set_driver(dev, 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 = true; + } else { + pm_request_idle(dev); + } + + if (dev->parent) + pm_runtime_put(dev->parent); + } +out_unlock: + device_unlock(dev); + if (async) + async_schedule_dev(__device_attach_async_helper, dev); + return ret; } /** @@ -411,34 +1071,102 @@ static int __device_attach(struct device_driver *drv, void *data) */ int device_attach(struct device *dev) { - int ret = 0; + return __device_attach(dev, false); +} +EXPORT_SYMBOL_GPL(device_attach); + +void device_initial_probe(struct device *dev) +{ + struct subsys_private *sp = bus_to_subsys(dev->bus); + + if (!sp) + return; + if (sp->drivers_autoprobe) + __device_attach(dev, true); + + subsys_put(sp); +} + +/* + * __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); - if (dev->driver) { - if (klist_node_attached(&dev->p->knode_driver)) { - ret = 1; - goto out_unlock; - } - ret = device_bind_driver(dev); - if (ret == 0) - ret = 1; - else { - dev->driver = NULL; - ret = 0; - } - } else { - ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach); - pm_request_idle(dev); - } -out_unlock: +} + +/* + * __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 @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. Returns 0 on success, -ERR on failure. + */ +int device_driver_attach(const struct device_driver *drv, struct device *dev) +{ + int ret; + + __device_driver_lock(dev, dev->parent); + ret = __driver_probe_device(drv, dev); + __device_driver_unlock(dev, dev->parent); + + /* also return probe errors as normal negative errnos */ + if (ret > 0) + ret = -ret; + if (ret == -EPROBE_DEFER) + return -EAGAIN; return ret; } -EXPORT_SYMBOL_GPL(device_attach); +EXPORT_SYMBOL_GPL(device_driver_attach); + +static void __driver_attach_async_helper(void *_dev, async_cookie_t cookie) +{ + struct device *dev = _dev; + const struct device_driver *drv; + int ret; + + __device_driver_lock(dev, dev->parent); + drv = dev->p->async_driver; + dev->p->async_driver = NULL; + 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; + const struct device_driver *drv = data; + bool async = false; + int ret; /* * Lock device and try to bind to it. We drop the error @@ -450,17 +1178,52 @@ static int __driver_attach(struct device *dev, void *data) * is an error. */ - if (!driver_match_device(drv, dev)) + 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); + /* + * Driver could not match with device, but may match with + * another device on the bus. + */ + return 0; + } else if (ret < 0) { + dev_dbg(dev, "Bus failed to match device: %d\n", ret); + /* + * Driver could not match with device, but may match with + * another device on the bus. + */ return 0; + } /* ret > 0 means positive match */ - if (dev->parent) /* Needed for USB */ - device_lock(dev->parent); - device_lock(dev); - if (!dev->driver) - driver_probe_device(drv, dev); - device_unlock(dev); - if (dev->parent) - device_unlock(dev->parent); + 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 && !dev->p->async_driver) { + get_device(dev); + dev->p->async_driver = drv; + async = true; + } + device_unlock(dev); + if (async) + async_schedule_dev(__driver_attach_async_helper, dev); + return 0; + } + + __device_driver_lock(dev, dev->parent); + driver_probe_device(drv, dev); + __device_driver_unlock(dev, dev->parent); return 0; } @@ -474,9 +1237,10 @@ static int __driver_attach(struct device *dev, void *data) * returns 0 and the @dev->driver is set, we've found a * compatible pair. */ -int driver_attach(struct device_driver *drv) +int driver_attach(const struct device_driver *drv) { - return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach); + /* The (void *) will be put back to const * in __driver_attach() */ + return bus_for_each_dev(drv->bus, NULL, (void *)drv, __driver_attach); } EXPORT_SYMBOL_GPL(driver_attach); @@ -484,7 +1248,7 @@ 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) +static void __device_release_driver(struct device *dev, struct device *parent) { struct device_driver *drv; @@ -492,37 +1256,67 @@ static void __device_release_driver(struct device *dev) 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); + bus_notify(dev, BUS_NOTIFY_UNBIND_DRIVER); + + pm_runtime_put_sync(dev); + + device_remove(dev); + + if (dev->bus && dev->bus->dma_cleanup) + dev->bus->dma_cleanup(dev); - pm_runtime_put(dev); + device_unbind_cleanup(dev); + device_links_driver_cleanup(dev); - if (dev->bus && dev->bus->remove) - dev->bus->remove(dev); - else if (drv->remove) - drv->remove(dev); - devres_release_all(dev); - dev->driver = NULL; - dev_set_drvdata(dev, NULL); klist_remove(&dev->p->knode_driver); - if (dev->bus) - blocking_notifier_call_chain(&dev->bus->p->bus_notifier, - BUS_NOTIFY_UNBOUND_DRIVER, - dev); + device_pm_check_callbacks(dev); + bus_notify(dev, BUS_NOTIFY_UNBOUND_DRIVER); + kobject_uevent(&dev->kobj, KOBJ_UNBIND); } } +void device_release_driver_internal(struct device *dev, + const 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) { @@ -531,68 +1325,47 @@ void device_release_driver(struct device *dev) * within their ->remove callback for the same device, they * will deadlock right here. */ - device_lock(dev); - __device_release_driver(dev); - device_unlock(dev); + 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) +void driver_detach(const 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, + 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); - - if (dev->parent) /* Needed for USB */ - device_lock(dev->parent); - device_lock(dev); - if (dev->driver == drv) - __device_release_driver(dev); - device_unlock(dev); - if (dev->parent) - device_unlock(dev->parent); + device_release_driver_internal(dev, drv, dev->parent); put_device(dev); } } - -/* - * These exports can't be _GPL due to .h files using this within them, and it - * might break something that was previously working... - */ -void *dev_get_drvdata(const struct device *dev) -{ - if (dev && dev->p) - return dev->p->driver_data; - return NULL; -} -EXPORT_SYMBOL(dev_get_drvdata); - -int dev_set_drvdata(struct device *dev, void *data) -{ - int error; - - if (!dev->p) { - error = device_private_init(dev); - if (error) - return error; - } - dev->p->driver_data = data; - return 0; -} -EXPORT_SYMBOL(dev_set_drvdata); |