2 * platform.c - platform 'pseudo' bus for legacy devices
4 * Copyright (c) 2002-3 Patrick Mochel
5 * Copyright (c) 2002-3 Open Source Development Labs
7 * This file is released under the GPLv2
9 * Please see Documentation/driver-model/platform.txt for more
13 #include <linux/string.h>
14 #include <linux/platform_device.h>
15 #include <linux/module.h>
16 #include <linux/init.h>
17 #include <linux/dma-mapping.h>
18 #include <linux/bootmem.h>
19 #include <linux/err.h>
20 #include <linux/slab.h>
21 #include <linux/pm_runtime.h>
25 #define to_platform_driver(drv) (container_of((drv), struct platform_driver, \
28 struct device platform_bus = {
29 .init_name = "platform",
31 EXPORT_SYMBOL_GPL(platform_bus);
34 * platform_get_resource - get a resource for a device
35 * @dev: platform device
36 * @type: resource type
37 * @num: resource index
39 struct resource *platform_get_resource(struct platform_device *dev,
40 unsigned int type, unsigned int num)
44 for (i = 0; i < dev->num_resources; i++) {
45 struct resource *r = &dev->resource[i];
47 if (type == resource_type(r) && num-- == 0)
52 EXPORT_SYMBOL_GPL(platform_get_resource);
55 * platform_get_irq - get an IRQ for a device
56 * @dev: platform device
57 * @num: IRQ number index
59 int platform_get_irq(struct platform_device *dev, unsigned int num)
61 struct resource *r = platform_get_resource(dev, IORESOURCE_IRQ, num);
63 return r ? r->start : -ENXIO;
65 EXPORT_SYMBOL_GPL(platform_get_irq);
68 * platform_get_resource_byname - get a resource for a device by name
69 * @dev: platform device
70 * @type: resource type
71 * @name: resource name
73 struct resource *platform_get_resource_byname(struct platform_device *dev,
79 for (i = 0; i < dev->num_resources; i++) {
80 struct resource *r = &dev->resource[i];
82 if (type == resource_type(r) && !strcmp(r->name, name))
87 EXPORT_SYMBOL_GPL(platform_get_resource_byname);
90 * platform_get_irq - get an IRQ for a device
91 * @dev: platform device
94 int platform_get_irq_byname(struct platform_device *dev, const char *name)
96 struct resource *r = platform_get_resource_byname(dev, IORESOURCE_IRQ,
99 return r ? r->start : -ENXIO;
101 EXPORT_SYMBOL_GPL(platform_get_irq_byname);
104 * platform_add_devices - add a numbers of platform devices
105 * @devs: array of platform devices to add
106 * @num: number of platform devices in array
108 int platform_add_devices(struct platform_device **devs, int num)
112 for (i = 0; i < num; i++) {
113 ret = platform_device_register(devs[i]);
116 platform_device_unregister(devs[i]);
123 EXPORT_SYMBOL_GPL(platform_add_devices);
125 struct platform_object {
126 struct platform_device pdev;
131 * platform_device_put
132 * @pdev: platform device to free
134 * Free all memory associated with a platform device. This function must
135 * _only_ be externally called in error cases. All other usage is a bug.
137 void platform_device_put(struct platform_device *pdev)
140 put_device(&pdev->dev);
142 EXPORT_SYMBOL_GPL(platform_device_put);
144 static void platform_device_release(struct device *dev)
146 struct platform_object *pa = container_of(dev, struct platform_object,
149 kfree(pa->pdev.dev.platform_data);
150 kfree(pa->pdev.resource);
155 * platform_device_alloc
156 * @name: base name of the device we're adding
159 * Create a platform device object which can have other objects attached
160 * to it, and which will have attached objects freed when it is released.
162 struct platform_device *platform_device_alloc(const char *name, int id)
164 struct platform_object *pa;
166 pa = kzalloc(sizeof(struct platform_object) + strlen(name), GFP_KERNEL);
168 strcpy(pa->name, name);
169 pa->pdev.name = pa->name;
171 device_initialize(&pa->pdev.dev);
172 pa->pdev.dev.release = platform_device_release;
175 return pa ? &pa->pdev : NULL;
177 EXPORT_SYMBOL_GPL(platform_device_alloc);
180 * platform_device_add_resources
181 * @pdev: platform device allocated by platform_device_alloc to add resources to
182 * @res: set of resources that needs to be allocated for the device
183 * @num: number of resources
185 * Add a copy of the resources to the platform device. The memory
186 * associated with the resources will be freed when the platform device is
189 int platform_device_add_resources(struct platform_device *pdev,
190 struct resource *res, unsigned int num)
194 r = kmalloc(sizeof(struct resource) * num, GFP_KERNEL);
196 memcpy(r, res, sizeof(struct resource) * num);
198 pdev->num_resources = num;
200 return r ? 0 : -ENOMEM;
202 EXPORT_SYMBOL_GPL(platform_device_add_resources);
205 * platform_device_add_data
206 * @pdev: platform device allocated by platform_device_alloc to add resources to
207 * @data: platform specific data for this platform device
208 * @size: size of platform specific data
210 * Add a copy of platform specific data to the platform device's
211 * platform_data pointer. The memory associated with the platform data
212 * will be freed when the platform device is released.
214 int platform_device_add_data(struct platform_device *pdev, const void *data,
217 void *d = kmemdup(data, size, GFP_KERNEL);
220 pdev->dev.platform_data = d;
225 EXPORT_SYMBOL_GPL(platform_device_add_data);
228 * platform_device_add - add a platform device to device hierarchy
229 * @pdev: platform device we're adding
231 * This is part 2 of platform_device_register(), though may be called
232 * separately _iff_ pdev was allocated by platform_device_alloc().
234 int platform_device_add(struct platform_device *pdev)
241 if (!pdev->dev.parent)
242 pdev->dev.parent = &platform_bus;
244 pdev->dev.bus = &platform_bus_type;
247 dev_set_name(&pdev->dev, "%s.%d", pdev->name, pdev->id);
249 dev_set_name(&pdev->dev, "%s", pdev->name);
251 for (i = 0; i < pdev->num_resources; i++) {
252 struct resource *p, *r = &pdev->resource[i];
255 r->name = dev_name(&pdev->dev);
259 if (resource_type(r) == IORESOURCE_MEM)
261 else if (resource_type(r) == IORESOURCE_IO)
262 p = &ioport_resource;
265 if (p && insert_resource(p, r)) {
267 "%s: failed to claim resource %d\n",
268 dev_name(&pdev->dev), i);
274 pr_debug("Registering platform device '%s'. Parent at %s\n",
275 dev_name(&pdev->dev), dev_name(pdev->dev.parent));
277 ret = device_add(&pdev->dev);
283 struct resource *r = &pdev->resource[i];
284 unsigned long type = resource_type(r);
286 if (type == IORESOURCE_MEM || type == IORESOURCE_IO)
292 EXPORT_SYMBOL_GPL(platform_device_add);
295 * platform_device_del - remove a platform-level device
296 * @pdev: platform device we're removing
298 * Note that this function will also release all memory- and port-based
299 * resources owned by the device (@dev->resource). This function must
300 * _only_ be externally called in error cases. All other usage is a bug.
302 void platform_device_del(struct platform_device *pdev)
307 device_del(&pdev->dev);
309 for (i = 0; i < pdev->num_resources; i++) {
310 struct resource *r = &pdev->resource[i];
311 unsigned long type = resource_type(r);
313 if (type == IORESOURCE_MEM || type == IORESOURCE_IO)
318 EXPORT_SYMBOL_GPL(platform_device_del);
321 * platform_device_register - add a platform-level device
322 * @pdev: platform device we're adding
324 int platform_device_register(struct platform_device *pdev)
326 device_initialize(&pdev->dev);
327 return platform_device_add(pdev);
329 EXPORT_SYMBOL_GPL(platform_device_register);
332 * platform_device_unregister - unregister a platform-level device
333 * @pdev: platform device we're unregistering
335 * Unregistration is done in 2 steps. First we release all resources
336 * and remove it from the subsystem, then we drop reference count by
337 * calling platform_device_put().
339 void platform_device_unregister(struct platform_device *pdev)
341 platform_device_del(pdev);
342 platform_device_put(pdev);
344 EXPORT_SYMBOL_GPL(platform_device_unregister);
347 * platform_device_register_simple
348 * @name: base name of the device we're adding
350 * @res: set of resources that needs to be allocated for the device
351 * @num: number of resources
353 * This function creates a simple platform device that requires minimal
354 * resource and memory management. Canned release function freeing memory
355 * allocated for the device allows drivers using such devices to be
356 * unloaded without waiting for the last reference to the device to be
359 * This interface is primarily intended for use with legacy drivers which
360 * probe hardware directly. Because such drivers create sysfs device nodes
361 * themselves, rather than letting system infrastructure handle such device
362 * enumeration tasks, they don't fully conform to the Linux driver model.
363 * In particular, when such drivers are built as modules, they can't be
366 struct platform_device *platform_device_register_simple(const char *name,
368 struct resource *res,
371 struct platform_device *pdev;
374 pdev = platform_device_alloc(name, id);
381 retval = platform_device_add_resources(pdev, res, num);
386 retval = platform_device_add(pdev);
393 platform_device_put(pdev);
394 return ERR_PTR(retval);
396 EXPORT_SYMBOL_GPL(platform_device_register_simple);
399 * platform_device_register_data
400 * @parent: parent device for the device we're adding
401 * @name: base name of the device we're adding
403 * @data: platform specific data for this platform device
404 * @size: size of platform specific data
406 * This function creates a simple platform device that requires minimal
407 * resource and memory management. Canned release function freeing memory
408 * allocated for the device allows drivers using such devices to be
409 * unloaded without waiting for the last reference to the device to be
412 struct platform_device *platform_device_register_data(
413 struct device *parent,
414 const char *name, int id,
415 const void *data, size_t size)
417 struct platform_device *pdev;
420 pdev = platform_device_alloc(name, id);
426 pdev->dev.parent = parent;
429 retval = platform_device_add_data(pdev, data, size);
434 retval = platform_device_add(pdev);
441 platform_device_put(pdev);
442 return ERR_PTR(retval);
445 static int platform_drv_probe(struct device *_dev)
447 struct platform_driver *drv = to_platform_driver(_dev->driver);
448 struct platform_device *dev = to_platform_device(_dev);
450 return drv->probe(dev);
453 static int platform_drv_probe_fail(struct device *_dev)
458 static int platform_drv_remove(struct device *_dev)
460 struct platform_driver *drv = to_platform_driver(_dev->driver);
461 struct platform_device *dev = to_platform_device(_dev);
463 return drv->remove(dev);
466 static void platform_drv_shutdown(struct device *_dev)
468 struct platform_driver *drv = to_platform_driver(_dev->driver);
469 struct platform_device *dev = to_platform_device(_dev);
475 * platform_driver_register
476 * @drv: platform driver structure
478 int platform_driver_register(struct platform_driver *drv)
480 drv->driver.bus = &platform_bus_type;
482 drv->driver.probe = platform_drv_probe;
484 drv->driver.remove = platform_drv_remove;
486 drv->driver.shutdown = platform_drv_shutdown;
488 return driver_register(&drv->driver);
490 EXPORT_SYMBOL_GPL(platform_driver_register);
493 * platform_driver_unregister
494 * @drv: platform driver structure
496 void platform_driver_unregister(struct platform_driver *drv)
498 driver_unregister(&drv->driver);
500 EXPORT_SYMBOL_GPL(platform_driver_unregister);
503 * platform_driver_probe - register driver for non-hotpluggable device
504 * @drv: platform driver structure
505 * @probe: the driver probe routine, probably from an __init section
507 * Use this instead of platform_driver_register() when you know the device
508 * is not hotpluggable and has already been registered, and you want to
509 * remove its run-once probe() infrastructure from memory after the driver
510 * has bound to the device.
512 * One typical use for this would be with drivers for controllers integrated
513 * into system-on-chip processors, where the controller devices have been
514 * configured as part of board setup.
516 * Returns zero if the driver registered and bound to a device, else returns
517 * a negative error code and with the driver not registered.
519 int __init_or_module platform_driver_probe(struct platform_driver *drv,
520 int (*probe)(struct platform_device *))
524 /* make sure driver won't have bind/unbind attributes */
525 drv->driver.suppress_bind_attrs = true;
527 /* temporary section violation during probe() */
529 retval = code = platform_driver_register(drv);
532 * Fixup that section violation, being paranoid about code scanning
533 * the list of drivers in order to probe new devices. Check to see
534 * if the probe was successful, and make sure any forced probes of
537 spin_lock(&platform_bus_type.p->klist_drivers.k_lock);
539 if (code == 0 && list_empty(&drv->driver.p->klist_devices.k_list))
541 drv->driver.probe = platform_drv_probe_fail;
542 spin_unlock(&platform_bus_type.p->klist_drivers.k_lock);
545 platform_driver_unregister(drv);
548 EXPORT_SYMBOL_GPL(platform_driver_probe);
550 /* modalias support enables more hands-off userspace setup:
551 * (a) environment variable lets new-style hotplug events work once system is
552 * fully running: "modprobe $MODALIAS"
553 * (b) sysfs attribute lets new-style coldplug recover from hotplug events
554 * mishandled before system is fully running: "modprobe $(cat modalias)"
556 static ssize_t modalias_show(struct device *dev, struct device_attribute *a,
559 struct platform_device *pdev = to_platform_device(dev);
560 int len = snprintf(buf, PAGE_SIZE, "platform:%s\n", pdev->name);
562 return (len >= PAGE_SIZE) ? (PAGE_SIZE - 1) : len;
565 static struct device_attribute platform_dev_attrs[] = {
570 static int platform_uevent(struct device *dev, struct kobj_uevent_env *env)
572 struct platform_device *pdev = to_platform_device(dev);
574 add_uevent_var(env, "MODALIAS=%s%s", PLATFORM_MODULE_PREFIX,
575 (pdev->id_entry) ? pdev->id_entry->name : pdev->name);
579 static const struct platform_device_id *platform_match_id(
580 struct platform_device_id *id,
581 struct platform_device *pdev)
583 while (id->name[0]) {
584 if (strcmp(pdev->name, id->name) == 0) {
594 * platform_match - bind platform device to platform driver.
598 * Platform device IDs are assumed to be encoded like this:
599 * "<name><instance>", where <name> is a short description of the type of
600 * device, like "pci" or "floppy", and <instance> is the enumerated
601 * instance of the device, like '0' or '42'. Driver IDs are simply
602 * "<name>". So, extract the <name> from the platform_device structure,
603 * and compare it against the name of the driver. Return whether they match
606 static int platform_match(struct device *dev, struct device_driver *drv)
608 struct platform_device *pdev = to_platform_device(dev);
609 struct platform_driver *pdrv = to_platform_driver(drv);
611 /* match against the id table first */
613 return platform_match_id(pdrv->id_table, pdev) != NULL;
615 /* fall-back to driver name match */
616 return (strcmp(pdev->name, drv->name) == 0);
619 #ifdef CONFIG_PM_SLEEP
621 static int platform_legacy_suspend(struct device *dev, pm_message_t mesg)
623 struct platform_driver *pdrv = to_platform_driver(dev->driver);
624 struct platform_device *pdev = to_platform_device(dev);
627 if (dev->driver && pdrv->suspend)
628 ret = pdrv->suspend(pdev, mesg);
633 static int platform_legacy_resume(struct device *dev)
635 struct platform_driver *pdrv = to_platform_driver(dev->driver);
636 struct platform_device *pdev = to_platform_device(dev);
639 if (dev->driver && pdrv->resume)
640 ret = pdrv->resume(pdev);
645 static int platform_pm_prepare(struct device *dev)
647 struct device_driver *drv = dev->driver;
650 if (drv && drv->pm && drv->pm->prepare)
651 ret = drv->pm->prepare(dev);
656 static void platform_pm_complete(struct device *dev)
658 struct device_driver *drv = dev->driver;
660 if (drv && drv->pm && drv->pm->complete)
661 drv->pm->complete(dev);
664 #else /* !CONFIG_PM_SLEEP */
666 #define platform_pm_prepare NULL
667 #define platform_pm_complete NULL
669 #endif /* !CONFIG_PM_SLEEP */
671 #ifdef CONFIG_SUSPEND
673 static int platform_pm_suspend(struct device *dev)
675 struct device_driver *drv = dev->driver;
682 if (drv->pm->suspend)
683 ret = drv->pm->suspend(dev);
685 ret = platform_legacy_suspend(dev, PMSG_SUSPEND);
691 static int platform_pm_suspend_noirq(struct device *dev)
693 struct device_driver *drv = dev->driver;
700 if (drv->pm->suspend_noirq)
701 ret = drv->pm->suspend_noirq(dev);
707 static int platform_pm_resume(struct device *dev)
709 struct device_driver *drv = dev->driver;
717 ret = drv->pm->resume(dev);
719 ret = platform_legacy_resume(dev);
725 static int platform_pm_resume_noirq(struct device *dev)
727 struct device_driver *drv = dev->driver;
734 if (drv->pm->resume_noirq)
735 ret = drv->pm->resume_noirq(dev);
741 #else /* !CONFIG_SUSPEND */
743 #define platform_pm_suspend NULL
744 #define platform_pm_resume NULL
745 #define platform_pm_suspend_noirq NULL
746 #define platform_pm_resume_noirq NULL
748 #endif /* !CONFIG_SUSPEND */
750 #ifdef CONFIG_HIBERNATION
752 static int platform_pm_freeze(struct device *dev)
754 struct device_driver *drv = dev->driver;
762 ret = drv->pm->freeze(dev);
764 ret = platform_legacy_suspend(dev, PMSG_FREEZE);
770 static int platform_pm_freeze_noirq(struct device *dev)
772 struct device_driver *drv = dev->driver;
779 if (drv->pm->freeze_noirq)
780 ret = drv->pm->freeze_noirq(dev);
786 static int platform_pm_thaw(struct device *dev)
788 struct device_driver *drv = dev->driver;
796 ret = drv->pm->thaw(dev);
798 ret = platform_legacy_resume(dev);
804 static int platform_pm_thaw_noirq(struct device *dev)
806 struct device_driver *drv = dev->driver;
813 if (drv->pm->thaw_noirq)
814 ret = drv->pm->thaw_noirq(dev);
820 static int platform_pm_poweroff(struct device *dev)
822 struct device_driver *drv = dev->driver;
829 if (drv->pm->poweroff)
830 ret = drv->pm->poweroff(dev);
832 ret = platform_legacy_suspend(dev, PMSG_HIBERNATE);
838 static int platform_pm_poweroff_noirq(struct device *dev)
840 struct device_driver *drv = dev->driver;
847 if (drv->pm->poweroff_noirq)
848 ret = drv->pm->poweroff_noirq(dev);
854 static int platform_pm_restore(struct device *dev)
856 struct device_driver *drv = dev->driver;
863 if (drv->pm->restore)
864 ret = drv->pm->restore(dev);
866 ret = platform_legacy_resume(dev);
872 static int platform_pm_restore_noirq(struct device *dev)
874 struct device_driver *drv = dev->driver;
881 if (drv->pm->restore_noirq)
882 ret = drv->pm->restore_noirq(dev);
888 #else /* !CONFIG_HIBERNATION */
890 #define platform_pm_freeze NULL
891 #define platform_pm_thaw NULL
892 #define platform_pm_poweroff NULL
893 #define platform_pm_restore NULL
894 #define platform_pm_freeze_noirq NULL
895 #define platform_pm_thaw_noirq NULL
896 #define platform_pm_poweroff_noirq NULL
897 #define platform_pm_restore_noirq NULL
899 #endif /* !CONFIG_HIBERNATION */
901 #ifdef CONFIG_PM_RUNTIME
903 int __weak platform_pm_runtime_suspend(struct device *dev)
908 int __weak platform_pm_runtime_resume(struct device *dev)
913 int __weak platform_pm_runtime_idle(struct device *dev)
918 #else /* !CONFIG_PM_RUNTIME */
920 #define platform_pm_runtime_suspend NULL
921 #define platform_pm_runtime_resume NULL
922 #define platform_pm_runtime_idle NULL
924 #endif /* !CONFIG_PM_RUNTIME */
926 static const struct dev_pm_ops platform_dev_pm_ops = {
927 .prepare = platform_pm_prepare,
928 .complete = platform_pm_complete,
929 .suspend = platform_pm_suspend,
930 .resume = platform_pm_resume,
931 .freeze = platform_pm_freeze,
932 .thaw = platform_pm_thaw,
933 .poweroff = platform_pm_poweroff,
934 .restore = platform_pm_restore,
935 .suspend_noirq = platform_pm_suspend_noirq,
936 .resume_noirq = platform_pm_resume_noirq,
937 .freeze_noirq = platform_pm_freeze_noirq,
938 .thaw_noirq = platform_pm_thaw_noirq,
939 .poweroff_noirq = platform_pm_poweroff_noirq,
940 .restore_noirq = platform_pm_restore_noirq,
941 .runtime_suspend = platform_pm_runtime_suspend,
942 .runtime_resume = platform_pm_runtime_resume,
943 .runtime_idle = platform_pm_runtime_idle,
946 struct bus_type platform_bus_type = {
948 .dev_attrs = platform_dev_attrs,
949 .match = platform_match,
950 .uevent = platform_uevent,
951 .pm = &platform_dev_pm_ops,
953 EXPORT_SYMBOL_GPL(platform_bus_type);
955 int __init platform_bus_init(void)
959 early_platform_cleanup();
961 error = device_register(&platform_bus);
964 error = bus_register(&platform_bus_type);
966 device_unregister(&platform_bus);
970 #ifndef ARCH_HAS_DMA_GET_REQUIRED_MASK
971 u64 dma_get_required_mask(struct device *dev)
973 u32 low_totalram = ((max_pfn - 1) << PAGE_SHIFT);
974 u32 high_totalram = ((max_pfn - 1) >> (32 - PAGE_SHIFT));
977 if (!high_totalram) {
978 /* convert to mask just covering totalram */
979 low_totalram = (1 << (fls(low_totalram) - 1));
980 low_totalram += low_totalram - 1;
983 high_totalram = (1 << (fls(high_totalram) - 1));
984 high_totalram += high_totalram - 1;
985 mask = (((u64)high_totalram) << 32) + 0xffffffff;
989 EXPORT_SYMBOL_GPL(dma_get_required_mask);
992 static __initdata LIST_HEAD(early_platform_driver_list);
993 static __initdata LIST_HEAD(early_platform_device_list);
996 * early_platform_driver_register
997 * @epdrv: early_platform driver structure
998 * @buf: string passed from early_param()
1000 int __init early_platform_driver_register(struct early_platform_driver *epdrv,
1006 /* Simply add the driver to the end of the global list.
1007 * Drivers will by default be put on the list in compiled-in order.
1009 if (!epdrv->list.next) {
1010 INIT_LIST_HEAD(&epdrv->list);
1011 list_add_tail(&epdrv->list, &early_platform_driver_list);
1014 /* If the user has specified device then make sure the driver
1015 * gets prioritized. The driver of the last device specified on
1016 * command line will be put first on the list.
1018 n = strlen(epdrv->pdrv->driver.name);
1019 if (buf && !strncmp(buf, epdrv->pdrv->driver.name, n)) {
1020 list_move(&epdrv->list, &early_platform_driver_list);
1022 /* Allow passing parameters after device name */
1023 if (buf[n] == '\0' || buf[n] == ',')
1024 epdrv->requested_id = -1;
1026 epdrv->requested_id = simple_strtoul(&buf[n + 1],
1029 if (buf[n] != '.' || (tmp == &buf[n + 1])) {
1030 epdrv->requested_id = EARLY_PLATFORM_ID_ERROR;
1033 n += strcspn(&buf[n + 1], ",") + 1;
1039 if (epdrv->bufsize) {
1040 memcpy(epdrv->buffer, &buf[n],
1041 min_t(int, epdrv->bufsize, strlen(&buf[n]) + 1));
1042 epdrv->buffer[epdrv->bufsize - 1] = '\0';
1050 * early_platform_add_devices - add a numbers of early platform devices
1051 * @devs: array of early platform devices to add
1052 * @num: number of early platform devices in array
1054 void __init early_platform_add_devices(struct platform_device **devs, int num)
1059 /* simply add the devices to list */
1060 for (i = 0; i < num; i++) {
1061 dev = &devs[i]->dev;
1063 if (!dev->devres_head.next) {
1064 INIT_LIST_HEAD(&dev->devres_head);
1065 list_add_tail(&dev->devres_head,
1066 &early_platform_device_list);
1072 * early_platform_driver_register_all
1073 * @class_str: string to identify early platform driver class
1075 void __init early_platform_driver_register_all(char *class_str)
1077 /* The "class_str" parameter may or may not be present on the kernel
1078 * command line. If it is present then there may be more than one
1079 * matching parameter.
1081 * Since we register our early platform drivers using early_param()
1082 * we need to make sure that they also get registered in the case
1083 * when the parameter is missing from the kernel command line.
1085 * We use parse_early_options() to make sure the early_param() gets
1086 * called at least once. The early_param() may be called more than
1087 * once since the name of the preferred device may be specified on
1088 * the kernel command line. early_platform_driver_register() handles
1091 parse_early_options(class_str);
1095 * early_platform_match
1096 * @epdrv: early platform driver structure
1097 * @id: id to match against
1099 static __init struct platform_device *
1100 early_platform_match(struct early_platform_driver *epdrv, int id)
1102 struct platform_device *pd;
1104 list_for_each_entry(pd, &early_platform_device_list, dev.devres_head)
1105 if (platform_match(&pd->dev, &epdrv->pdrv->driver))
1113 * early_platform_left
1114 * @epdrv: early platform driver structure
1115 * @id: return true if id or above exists
1117 static __init int early_platform_left(struct early_platform_driver *epdrv,
1120 struct platform_device *pd;
1122 list_for_each_entry(pd, &early_platform_device_list, dev.devres_head)
1123 if (platform_match(&pd->dev, &epdrv->pdrv->driver))
1131 * early_platform_driver_probe_id
1132 * @class_str: string to identify early platform driver class
1133 * @id: id to match against
1134 * @nr_probe: number of platform devices to successfully probe before exiting
1136 static int __init early_platform_driver_probe_id(char *class_str,
1140 struct early_platform_driver *epdrv;
1141 struct platform_device *match;
1146 list_for_each_entry(epdrv, &early_platform_driver_list, list) {
1147 /* only use drivers matching our class_str */
1148 if (strcmp(class_str, epdrv->class_str))
1152 match_id = epdrv->requested_id;
1157 left += early_platform_left(epdrv, id);
1159 /* skip requested id */
1160 switch (epdrv->requested_id) {
1161 case EARLY_PLATFORM_ID_ERROR:
1162 case EARLY_PLATFORM_ID_UNSET:
1165 if (epdrv->requested_id == id)
1166 match_id = EARLY_PLATFORM_ID_UNSET;
1171 case EARLY_PLATFORM_ID_ERROR:
1172 pr_warning("%s: unable to parse %s parameter\n",
1173 class_str, epdrv->pdrv->driver.name);
1175 case EARLY_PLATFORM_ID_UNSET:
1179 match = early_platform_match(epdrv, match_id);
1183 if (epdrv->pdrv->probe(match))
1184 pr_warning("%s: unable to probe %s early.\n",
1185 class_str, match->name);
1201 * early_platform_driver_probe
1202 * @class_str: string to identify early platform driver class
1203 * @nr_probe: number of platform devices to successfully probe before exiting
1204 * @user_only: only probe user specified early platform devices
1206 int __init early_platform_driver_probe(char *class_str,
1213 for (i = -2; n < nr_probe; i++) {
1214 k = early_platform_driver_probe_id(class_str, i, nr_probe - n);
1229 * early_platform_cleanup - clean up early platform code
1231 void __init early_platform_cleanup(void)
1233 struct platform_device *pd, *pd2;
1235 /* clean up the devres list used to chain devices */
1236 list_for_each_entry_safe(pd, pd2, &early_platform_device_list,
1238 list_del(&pd->dev.devres_head);
1239 memset(&pd->dev.devres_head, 0, sizeof(pd->dev.devres_head));