diff options
42 files changed, 4186 insertions, 2914 deletions
diff --git a/Documentation/driver-model/design-patterns.txt b/Documentation/driver-model/design-patterns.txt new file mode 100644 index 000000000000..ba7b2df64904 --- /dev/null +++ b/Documentation/driver-model/design-patterns.txt @@ -0,0 +1,116 @@ + +Device Driver Design Patterns +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +This document describes a few common design patterns found in device drivers. +It is likely that subsystem maintainers will ask driver developers to +conform to these design patterns. + +1. State Container +2. container_of() + + +1. State Container +~~~~~~~~~~~~~~~~~~ + +While the kernel contains a few device drivers that assume that they will +only be probed() once on a certain system (singletons), it is custom to assume +that the device the driver binds to will appear in several instances. This +means that the probe() function and all callbacks need to be reentrant. + +The most common way to achieve this is to use the state container design +pattern. It usually has this form: + +struct foo { + spinlock_t lock; /* Example member */ + (...) +}; + +static int foo_probe(...) +{ + struct foo *foo; + + foo = devm_kzalloc(dev, sizeof(*foo), GFP_KERNEL); + if (!foo) + return -ENOMEM; + spin_lock_init(&foo->lock); + (...) +} + +This will create an instance of struct foo in memory every time probe() is +called. This is our state container for this instance of the device driver. +Of course it is then necessary to always pass this instance of the +state around to all functions that need access to the state and its members. + +For example, if the driver is registering an interrupt handler, you would +pass around a pointer to struct foo like this: + +static irqreturn_t foo_handler(int irq, void *arg) +{ + struct foo *foo = arg; + (...) +} + +static int foo_probe(...) +{ + struct foo *foo; + + (...) + ret = request_irq(irq, foo_handler, 0, "foo", foo); +} + +This way you always get a pointer back to the correct instance of foo in +your interrupt handler. + + +2. container_of() +~~~~~~~~~~~~~~~~~ + +Continuing on the above example we add an offloaded work: + +struct foo { + spinlock_t lock; + struct workqueue_struct *wq; + struct work_struct offload; + (...) +}; + +static void foo_work(struct work_struct *work) +{ + struct foo *foo = container_of(work, struct foo, offload); + + (...) +} + +static irqreturn_t foo_handler(int irq, void *arg) +{ + struct foo *foo = arg; + + queue_work(foo->wq, &foo->offload); + (...) +} + +static int foo_probe(...) +{ + struct foo *foo; + + foo->wq = create_singlethread_workqueue("foo-wq"); + INIT_WORK(&foo->offload, foo_work); + (...) +} + +The design pattern is the same for an hrtimer or something similar that will +return a single argument which is a pointer to a struct member in the +callback. + +container_of() is a macro defined in <linux/kernel.h> + +What container_of() does is to obtain a pointer to the containing struct from +a pointer to a member by a simple subtraction using the offsetof() macro from +standard C, which allows something similar to object oriented behaviours. +Notice that the contained member must not be a pointer, but an actual member +for this to work. + +We can see here that we avoid having global pointers to our struct foo * +instance this way, while still keeping the number of parameters passed to the +work function to a single pointer. diff --git a/Documentation/kobject.txt b/Documentation/kobject.txt index c5182bb2c16c..f87241dfed87 100644 --- a/Documentation/kobject.txt +++ b/Documentation/kobject.txt @@ -342,7 +342,10 @@ kset use: When you are finished with the kset, call: void kset_unregister(struct kset *kset); -to destroy it. +to destroy it. This removes the kset from sysfs and decrements its reference +count. When the reference count goes to zero, the kset will be released. +Because other references to the kset may still exist, the release may happen +after kset_unregister() returns. An example of using a kset can be seen in the samples/kobject/kset-example.c file in the kernel tree. diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c index 4a6ff747aaad..8fffd845e22b 100644 --- a/arch/x86/kernel/cpu/microcode/amd.c +++ b/arch/x86/kernel/cpu/microcode/amd.c @@ -433,7 +433,7 @@ static enum ucode_state request_microcode_amd(int cpu, struct device *device, if (c->x86 >= 0x15) snprintf(fw_name, sizeof(fw_name), "amd-ucode/microcode_amd_fam%.2xh.bin", c->x86); - if (request_firmware(&fw, (const char *)fw_name, device)) { + if (request_firmware_direct(&fw, (const char *)fw_name, device)) { pr_debug("failed to load file %s\n", fw_name); goto out; } diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c index 5fb2cebf556b..a276fa75d9b5 100644 --- a/arch/x86/kernel/cpu/microcode/intel.c +++ b/arch/x86/kernel/cpu/microcode/intel.c @@ -278,7 +278,7 @@ static enum ucode_state request_microcode_fw(int cpu, struct device *device, sprintf(name, "intel-ucode/%02x-%02x-%02x", c->x86, c->x86_model, c->x86_mask); - if (request_firmware(&firmware, name, device)) { + if (request_firmware_direct(&firmware, name, device)) { pr_debug("data file %s load failed\n", name); return UCODE_NFOUND; } diff --git a/drivers/base/Makefile b/drivers/base/Makefile index 94e8a80e87f8..870ecfd503af 100644 --- a/drivers/base/Makefile +++ b/drivers/base/Makefile @@ -1,6 +1,6 @@ # Makefile for the Linux device tree -obj-y := core.o bus.o dd.o syscore.o \ +obj-y := component.o core.o bus.o dd.o syscore.o \ driver.o class.o platform.o \ cpu.o firmware.o init.o map.o devres.o \ attribute_container.o transport_class.o \ diff --git a/drivers/base/bus.c b/drivers/base/bus.c index 73f6c2925281..59dc8086e4fa 100644 --- a/drivers/base/bus.c +++ b/drivers/base/bus.c @@ -146,8 +146,19 @@ void bus_remove_file(struct bus_type *bus, struct bus_attribute *attr) } EXPORT_SYMBOL_GPL(bus_remove_file); +static void bus_release(struct kobject *kobj) +{ + struct subsys_private *priv = + container_of(kobj, typeof(*priv), subsys.kobj); + struct bus_type *bus = priv->bus; + + kfree(priv); + bus->p = NULL; +} + static struct kobj_type bus_ktype = { .sysfs_ops = &bus_sysfs_ops, + .release = bus_release, }; static int bus_uevent_filter(struct kset *kset, struct kobject *kobj) @@ -953,8 +964,6 @@ void bus_unregister(struct bus_type *bus) kset_unregister(bus->p->devices_kset); bus_remove_file(bus, &bus_attr_uevent); kset_unregister(&bus->p->subsys); - kfree(bus->p); - bus->p = NULL; } EXPORT_SYMBOL_GPL(bus_unregister); diff --git a/drivers/base/component.c b/drivers/base/component.c new file mode 100644 index 000000000000..c53efe6c6d8e --- /dev/null +++ b/drivers/base/component.c @@ -0,0 +1,382 @@ +/* + * Componentized device handling. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This is work in progress. We gather up the component devices into a list, + * and bind them when instructed. At the moment, we're specific to the DRM + * subsystem, and only handles one master device, but this doesn't have to be + * the case. + */ +#include <linux/component.h> +#include <linux/device.h> +#include <linux/kref.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/slab.h> + +struct master { + struct list_head node; + struct list_head components; + bool bound; + + const struct component_master_ops *ops; + struct device *dev; +}; + +struct component { + struct list_head node; + struct list_head master_node; + struct master *master; + bool bound; + + const struct component_ops *ops; + struct device *dev; +}; + +static DEFINE_MUTEX(component_mutex); +static LIST_HEAD(component_list); +static LIST_HEAD(masters); + +static struct master *__master_find(struct device *dev, + const struct component_master_ops *ops) +{ + struct master *m; + + list_for_each_entry(m, &masters, node) + if (m->dev == dev && (!ops || m->ops == ops)) + return m; + + return NULL; +} + +/* Attach an unattached component to a master. */ +static void component_attach_master(struct master *master, struct component *c) +{ + c->master = master; + + list_add_tail(&c->master_node, &master->components); +} + +/* Detach a component from a master. */ +static void component_detach_master(struct master *master, struct component *c) +{ + list_del(&c->master_node); + + c->master = NULL; +} + +int component_master_add_child(struct master *master, + int (*compare)(struct device *, void *), void *compare_data) +{ + struct component *c; + int ret = -ENXIO; + + list_for_each_entry(c, &component_list, node) { + if (c->master) + continue; + + if (compare(c->dev, compare_data)) { + component_attach_master(master, c); + ret = 0; + break; + } + } + + return ret; +} +EXPORT_SYMBOL_GPL(component_master_add_child); + +/* Detach all attached components from this master */ +static void master_remove_components(struct master *master) +{ + while (!list_empty(&master->components)) { + struct component *c = list_first_entry(&master->components, + struct component, master_node); + + WARN_ON(c->master != master); + + component_detach_master(master, c); + } +} + +/* + * Try to bring up a master. If component is NULL, we're interested in + * this master, otherwise it's a component which must be present to try + * and bring up the master. + * + * Returns 1 for successful bringup, 0 if not ready, or -ve errno. + */ +static int try_to_bring_up_master(struct master *master, + struct component *component) +{ + int ret = 0; + + if (!master->bound) { + /* + * Search the list of components, looking for components that + * belong to this master, and attach them to the master. + */ + if (master->ops->add_components(master->dev, master)) { + /* Failed to find all components */ + master_remove_components(master); + ret = 0; + goto out; + } + + if (component && component->master != master) { + master_remove_components(master); + ret = 0; + goto out; + } + + /* Found all components */ + ret = master->ops->bind(master->dev); + if (ret < 0) { + master_remove_components(master); + goto out; + } + + master->bound = true; + ret = 1; + } +out: + + return ret; +} + +static int try_to_bring_up_masters(struct component *component) +{ + struct master *m; + int ret = 0; + + list_for_each_entry(m, &masters, node) { + ret = try_to_bring_up_master(m, component); + if (ret != 0) + break; + } + + return ret; +} + +static void take_down_master(struct master *master) +{ + if (master->bound) { + master->ops->unbind(master->dev); + master->bound = false; + } + + master_remove_components(master); +} + +int component_master_add(struct device *dev, + const struct component_master_ops *ops) +{ + struct master *master; + int ret; + + master = kzalloc(sizeof(*master), GFP_KERNEL); + if (!master) + return -ENOMEM; + + master->dev = dev; + master->ops = ops; + INIT_LIST_HEAD(&master->components); + + /* Add to the list of available masters. */ + mutex_lock(&component_mutex); + list_add(&master->node, &masters); + + ret = try_to_bring_up_master(master, NULL); + + if (ret < 0) { + /* Delete off the list if we weren't successful */ + list_del(&master->node); + kfree(master); + } + mutex_unlock(&component_mutex); + + return ret < 0 ? ret : 0; +} +EXPORT_SYMBOL_GPL(component_master_add); + +void component_master_del(struct device *dev, + const struct component_master_ops *ops) +{ + struct master *master; + + mutex_lock(&component_mutex); + master = __master_find(dev, ops); + if (master) { + take_down_master(master); + + list_del(&master->node); + kfree(master); + } + mutex_unlock(&component_mutex); +} +EXPORT_SYMBOL_GPL(component_master_del); + +static void component_unbind(struct component *component, + struct master *master, void *data) +{ + WARN_ON(!component->bound); + + component->ops->unbind(component->dev, master->dev, data); + component->bound = false; + + /* Release all resources claimed in the binding of this component */ + devres_release_group(component->dev, component); +} + +void component_unbind_all(struct device *master_dev, void *data) +{ + struct master *master; + struct component *c; + + WARN_ON(!mutex_is_locked(&component_mutex)); + + master = __master_find(master_dev, NULL); + if (!master) + return; + + list_for_each_entry_reverse(c, &master->components, master_node) + component_unbind(c, master, data); +} +EXPORT_SYMBOL_GPL(component_unbind_all); + +static int component_bind(struct component *component, struct master *master, + void *data) +{ + int ret; + + /* + * Each component initialises inside its own devres group. + * This allows us to roll-back a failed component without + * affecting anything else. + */ + if (!devres_open_group(master->dev, NULL, GFP_KERNEL)) + return -ENOMEM; + + /* + * Also open a group for the device itself: this allows us + * to release the resources claimed against the sub-device + * at the appropriate moment. + */ + if (!devres_open_group(component->dev, component, GFP_KERNEL)) { + devres_release_group(master->dev, NULL); + return -ENOMEM; + } + + dev_dbg(master->dev, "binding %s (ops %ps)\n", + dev_name(component->dev), component->ops); + + ret = component->ops->bind(component->dev, master->dev, data); + if (!ret) { + component->bound = true; + + /* + * Close the component device's group so that resources + * allocated in the binding are encapsulated for removal + * at unbind. Remove the group on the DRM device as we + * can clean those resources up independently. + */ + devres_close_group(component->dev, NULL); + devres_remove_group(master->dev, NULL); + + dev_info(master->dev, "bound %s (ops %ps)\n", + dev_name(component->dev), component->ops); + } else { + devres_release_group(component->dev, NULL); + devres_release_group(master->dev, NULL); + + dev_err(master->dev, "failed to bind %s (ops %ps): %d\n", + dev_name(component->dev), component->ops, ret); + } + + return ret; +} + +int component_bind_all(struct device *master_dev, void *data) +{ + struct master *master; + struct component *c; + int ret = 0; + + WARN_ON(!mutex_is_locked(&component_mutex)); + + master = __master_find(master_dev, NULL); + if (!master) + return -EINVAL; + + list_for_each_entry(c, &master->components, master_node) { + ret = component_bind(c, master, data); + if (ret) + break; + } + + if (ret != 0) { + list_for_each_entry_continue_reverse(c, &master->components, + master_node) + component_unbind(c, master, data); + } + + return ret; +} +EXPORT_SYMBOL_GPL(component_bind_all); + +int component_add(struct device *dev, const struct component_ops *ops) +{ + struct component *component; + int ret; + + component = kzalloc(sizeof(*component), GFP_KERNEL); + if (!component) + return -ENOMEM; + + component->ops = ops; + component->dev = dev; + + dev_dbg(dev, "adding component (ops %ps)\n", ops); + + mutex_lock(&component_mutex); + list_add_tail(&component->node, &component_list); + + ret = try_to_bring_up_masters(component); + if (ret < 0) { + list_del(&component->node); + + kfree(component); + } + mutex_unlock(&component_mutex); + + return ret < 0 ? ret : 0; +} +EXPORT_SYMBOL_GPL(component_add); + +void component_del(struct device *dev, const struct component_ops *ops) +{ + struct component *c, *component = NULL; + + mutex_lock(&component_mutex); + list_for_each_entry(c, &component_list, node) + if (c->dev == dev && c->ops == ops) { + list_del(&c->node); + component = c; + break; + } + + if (component && component->master) + take_down_master(component->master); + + mutex_unlock(&component_mutex); + + WARN_ON(!component); + kfree(component); +} +EXPORT_SYMBOL_GPL(component_del); + +MODULE_LICENSE("GPL v2"); diff --git a/drivers/base/core.c b/drivers/base/core.c index 67b180d855b2..2b567177ef78 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -491,11 +491,13 @@ static int device_add_attrs(struct device *dev) if (device_supports_offline(dev) && !dev->offline_disabled) { error = device_create_file(dev, &dev_attr_online); if (error) - goto err_remove_type_groups; + goto err_remove_dev_groups; } return 0; + err_remove_dev_groups: + device_remove_groups(dev, dev->groups); err_remove_type_groups: if (type) device_remove_groups(dev, type->groups); @@ -1603,6 +1605,7 @@ device_create_groups_vargs(struct class *class, struct device *parent, goto error; } + device_initialize(dev); dev->devt = devt; dev->class = class; dev->parent = parent; @@ -1614,7 +1617,7 @@ device_create_groups_vargs(struct class *class, struct device *parent, if (retval) goto error; - retval = device_register(dev); + retval = device_add(dev); if (retval) goto error; diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c index 0f3820121e02..25798db14553 100644 --- a/drivers/base/devtmpfs.c +++ b/drivers/base/devtmpfs.c @@ -299,7 +299,7 @@ static int handle_remove(const char *nodename, struct device *dev) { struct path parent; struct dentry *dentry; - int deleted = 1; + int deleted = 0; int err; dentry = kern_path_locked(nodename, &parent); diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c index eb8fb94ae2c5..8a97ddfa6122 100644 --- a/drivers/base/firmware_class.c +++ b/drivers/base/firmware_class.c @@ -96,6 +96,15 @@ static inline long firmware_loading_timeout(void) return loading_timeout > 0 ? loading_timeout * HZ : MAX_SCHEDULE_TIMEOUT; } +/* firmware behavior options */ +#define FW_OPT_UEVENT (1U << 0) +#define FW_OPT_NOWAIT (1U << 1) +#ifdef CONFIG_FW_LOADER_USER_HELPER +#define FW_OPT_FALLBACK (1U << 2) +#else +#define FW_OPT_FALLBACK 0 +#endif + struct firmware_cache { /* firmware_buf instance will be added into the below list */ spinlock_t lock; @@ -219,6 +228,7 @@ static int fw_lookup_and_allocate_buf(const char *fw_name, } static void __fw_free_buf(struct kref *ref) + __releases(&fwc->lock) { struct firmware_buf *buf = to_fwbuf(ref); struct firmware_cache *fwc = buf->fwc; @@ -270,21 +280,21 @@ module_param_string(path, fw_path_para, sizeof(fw_path_para), 0644); MODULE_PARM_DESC(path, "customized firmware image search path with a higher priority than default path"); /* Don't inline this: 'struct kstat' is biggish */ -static noinline_for_stack long fw_file_size(struct file *file) +static noinline_for_stack int fw_file_size(struct file *file) { struct kstat st; if (vfs_getattr(&file->f_path, &st)) return -1; if (!S_ISREG(st.mode)) return -1; - if (st.size != (long)st.size) + if (st.size != (int)st.size) return -1; return st.size; } static int fw_read_file_contents(struct file *file, struct firmware_buf *fw_buf) { - long size; + int size; char *buf; int rc; @@ -820,7 +830,7 @@ static void firmware_class_timeout_work(struct work_struct *work) static struct firmware_priv * fw_create_instance(struct firmware *firmware, const char *fw_name, - struct device *device, bool uevent, bool nowait) + struct device *device, unsigned int opt_flags) { struct firmware_priv *fw_priv; struct device *f_dev; @@ -832,7 +842,7 @@ fw_create_instance(struct firmware *firmware, const char *fw_name, goto exit; } - fw_priv->nowait = nowait; + fw_priv->nowait = !!(opt_flags & FW_OPT_NOWAIT); fw_priv->fw = firmware; INIT_DELAYED_WORK(&fw_priv->timeout_work, firmware_class_timeout_work); @@ -848,8 +858,8 @@ exit: } /* load a firmware via user helper */ -static int _request_firmware_load(struct firmware_priv *fw_priv, bool uevent, - long timeout) +static int _request_firmware_load(struct firmware_priv *fw_priv, + unsigned int opt_flags, long timeout) { int retval = 0; struct device *f_dev = &fw_priv->dev; @@ -885,7 +895,7 @@ static int _request_firmware_load(struct firmware_priv *fw_priv, bool uevent, goto err_del_bin_attr; } - if (uevent) { + if (opt_flags & FW_OPT_UEVENT) { buf->need_uevent = true; dev_set_uevent_suppress(f_dev, false); dev_dbg(f_dev, "firmware: requesting %s\n", buf->fw_id); @@ -911,16 +921,16 @@ err_put_dev: static int fw_load_from_user_helper(struct firmware *firmware, const char *name, struct device *device, - bool uevent, bool nowait, long timeout) + unsigned int opt_flags, long timeout) { struct firmware_priv *fw_priv; - fw_priv = fw_create_instance(firmware, name, device, uevent, nowait); + fw_priv = fw_create_instance(firmware, name, device, opt_flags); if (IS_ERR(fw_priv)) return PTR_ERR(fw_priv); fw_priv->buf = firmware->priv; - return _request_firmware_load(fw_priv, uevent, timeout); + return _request_firmware_load(fw_priv, opt_flags, timeout); } #ifdef CONFIG_PM_SLEEP @@ -942,7 +952,7 @@ static void kill_requests_without_uevent(void) #else /* CONFIG_FW_LOADER_USER_HELPER */ static inline int fw_load_from_user_helper(struct firmware *firmware, const char *name, - struct device *device, bool uevent, bool nowait, + struct device *device, unsigned int opt_flags, long timeout) { return -ENOENT; @@ -1023,7 +1033,7 @@ _request_firmware_prepare(struct firmware **firmware_p, const char *name, } static int assign_firmware_buf(struct firmware *fw, struct device *device, - bool skip_cache) + unsigned int opt_flags) { struct firmware_buf *buf = fw->priv; @@ -1040,7 +1050,8 @@ static int assign_firmware_buf(struct firmware *fw, struct device *device, * device may has been deleted already, but the problem * should be fixed in devres or driver core. */ - if (device && !skip_cache) + /* don't cache firmware handled without uevent */ + if (device && (opt_flags & FW_OPT_UEVENT)) fw_add_devm_name(device, buf->fw_id); /* @@ -1061,7 +1072,7 @@ static int assign_firmware_buf(struct firmware *fw, struct device *device, /* called from request_firmware() and request_firmware_work_func() */ static int _request_firmware(const struct firmware **firmware_p, const char *name, - struct device *device, bool uevent, bool nowait) + struct device *device, unsigned int opt_flags) { struct firmware *fw; long timeout; @@ -1076,7 +1087,7 @@ _request_firmware(const struct firmware **firmware_p, const char *name, ret = 0; timeout = firmware_loading_timeout(); - if (nowait) { + if (opt_flags & FW_OPT_NOWAIT) { timeout = usermodehelper_read_lock_wait(timeout); if (!timeout) { dev_dbg(device, "firmware: %s loading timed out\n", @@ -1095,16 +1106,18 @@ _request_firmware(const struct firmware **firmware_p, const char *name, ret = fw_get_filesystem_firmware(device, fw->priv); if (ret) { - dev_warn(device, "Direct firmware load failed with error %d\n", - ret); - dev_warn(device, "Falling back to user helper\n"); - ret = fw_load_from_user_helper(fw, name, device, - uevent, nowait, timeout); + if (opt_flags & FW_OPT_FALLBACK) { + dev_warn(device, + "Direct firmware load failed with error %d\n", + ret); + dev_warn(device, "Falling back to user helper\n"); + ret = fw_load_from_user_helper(fw, name, device, + opt_flags, timeout); + } } - /* don't cache firmware handled without uevent */ if (!ret) - ret = assign_firmware_buf(fw, device, !uevent); + ret = assign_firmware_buf(fw, device, opt_flags); usermodehelper_read_unlock(); @@ -1146,12 +1159,37 @@ request_firmware(const struct firmware **firmware_p, const char *name, /* Need to pin this module until return */ __module_get(THIS_MODULE); - ret = _request_firmware(firmware_p, name, device, true, false); + ret = _request_firmware(firmware_p, name, device, + FW_OPT_UEVENT | FW_OPT_FALLBACK); module_put(THIS_MODULE); return ret; } EXPORT_SYMBOL(request_firmware); +#ifdef CONFIG_FW_LOADER_USER_HE |