summaryrefslogtreecommitdiff
path: root/include/dm/device.h
blob: 2d8b716ef5e951fd1f5501170762526250e6f353 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
/* SPDX-License-Identifier: GPL-2.0+ */
/*
 * Copyright (c) 2013 Google, Inc
 *
 * (C) Copyright 2012
 * Pavel Herrmann <morpheus.ibis@gmail.com>
 * Marek Vasut <marex@denx.de>
 */

#ifndef _DM_DEVICE_H
#define _DM_DEVICE_H

#include <dm/ofnode.h>
#include <dm/uclass-id.h>
#include <fdtdec.h>
#include <linker_lists.h>
#include <linux/compat.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/printk.h>

struct driver_info;

/* Driver is active (probed). Cleared when it is removed */
#define DM_FLAG_ACTIVATED		(1 << 0)

/* DM is responsible for allocating and freeing platdata */
#define DM_FLAG_ALLOC_PDATA		(1 << 1)

/* DM should init this device prior to relocation */
#define DM_FLAG_PRE_RELOC		(1 << 2)

/* DM is responsible for allocating and freeing parent_platdata */
#define DM_FLAG_ALLOC_PARENT_PDATA	(1 << 3)

/* DM is responsible for allocating and freeing uclass_platdata */
#define DM_FLAG_ALLOC_UCLASS_PDATA	(1 << 4)

/* Allocate driver private data on a DMA boundary */
#define DM_FLAG_ALLOC_PRIV_DMA		(1 << 5)

/* Device is bound */
#define DM_FLAG_BOUND			(1 << 6)

/* Device name is allocated and should be freed on unbind() */
#define DM_FLAG_NAME_ALLOCED		(1 << 7)

/* Device has platform data provided by of-platdata */
#define DM_FLAG_OF_PLATDATA		(1 << 8)

/*
 * Call driver remove function to stop currently active DMA transfers or
 * give DMA buffers back to the HW / controller. This may be needed for
 * some drivers to do some final stage cleanup before the OS is called
 * (U-Boot exit)
 */
#define DM_FLAG_ACTIVE_DMA		(1 << 9)

/*
 * Call driver remove function to do some final configuration, before
 * U-Boot exits and the OS is started
 */
#define DM_FLAG_OS_PREPARE		(1 << 10)

/* DM does not enable/disable the power domains corresponding to this device */
#define DM_FLAG_DEFAULT_PD_CTRL_OFF	(1 << 11)

/* Driver platdata has been read. Cleared when the device is removed */
#define DM_FLAG_PLATDATA_VALID		(1 << 12)

/*
 * One or multiple of these flags are passed to device_remove() so that
 * a selective device removal as specified by the remove-stage and the
 * driver flags can be done.
 */
enum {
	/* Normal remove, remove all devices */
	DM_REMOVE_NORMAL     = 1 << 0,

	/* Remove devices with active DMA */
	DM_REMOVE_ACTIVE_DMA = DM_FLAG_ACTIVE_DMA,

	/* Remove devices which need some final OS preparation steps */
	DM_REMOVE_OS_PREPARE = DM_FLAG_OS_PREPARE,

	/* Add more use cases here */

	/* Remove devices with any active flag */
	DM_REMOVE_ACTIVE_ALL = DM_REMOVE_ACTIVE_DMA | DM_REMOVE_OS_PREPARE,
};

/**
 * struct udevice - An instance of a driver
 *
 * This holds information about a device, which is a driver bound to a
 * particular port or peripheral (essentially a driver instance).
 *
 * A device will come into existence through a 'bind' call, either due to
 * a U_BOOT_DEVICE() macro (in which case platdata is non-NULL) or a node
 * in the device tree (in which case of_offset is >= 0). In the latter case
 * we translate the device tree information into platdata in a function
 * implemented by the driver ofdata_to_platdata method (called just before the
 * probe method if the device has a device tree node.
 *
 * All three of platdata, priv and uclass_priv can be allocated by the
 * driver, or you can use the auto_alloc_size members of struct driver and
 * struct uclass_driver to have driver model do this automatically.
 *
 * @driver: The driver used by this device
 * @name: Name of device, typically the FDT node name
 * @platdata: Configuration data for this device
 * @parent_platdata: The parent bus's configuration data for this device
 * @uclass_platdata: The uclass's configuration data for this device
 * @node: Reference to device tree node for this device
 * @driver_data: Driver data word for the entry that matched this device with
 *		its driver
 * @parent: Parent of this device, or NULL for the top level device
 * @priv: Private data for this device
 * @uclass: Pointer to uclass for this device
 * @uclass_priv: The uclass's private data for this device
 * @parent_priv: The parent's private data for this device
 * @uclass_node: Used by uclass to link its devices
 * @child_head: List of children of this device
 * @sibling_node: Next device in list of all devices
 * @flags: Flags for this device DM_FLAG_...
 * @req_seq: Requested sequence number for this device (-1 = any)
 * @seq: Allocated sequence number for this device (-1 = none). This is set up
 * when the device is probed and will be unique within the device's uclass.
 * @devres_head: List of memory allocations associated with this device.
 *		When CONFIG_DEVRES is enabled, devm_kmalloc() and friends will
 *		add to this list. Memory so-allocated will be freed
 *		automatically when the device is removed / unbound
 */
struct udevice {
	const struct driver *driver;
	const char *name;
	void *platdata;
	void *parent_platdata;
	void *uclass_platdata;
	ofnode node;
	ulong driver_data;
	struct udevice *parent;
	void *priv;
	struct uclass *uclass;
	void *uclass_priv;
	void *parent_priv;
	struct list_head uclass_node;
	struct list_head child_head;
	struct list_head sibling_node;
	uint32_t flags;
	int req_seq;
	int seq;
#ifdef CONFIG_DEVRES
	struct list_head devres_head;
#endif
};

/* Maximum sequence number supported */
#define DM_MAX_SEQ	999

/* Returns the operations for a device */
#define device_get_ops(dev)	(dev->driver->ops)

/* Returns non-zero if the device is active (probed and not removed) */
#define device_active(dev)	((dev)->flags & DM_FLAG_ACTIVATED)

static inline int dev_of_offset(const struct udevice *dev)
{
	return ofnode_to_offset(dev->node);
}

static inline void dev_set_of_offset(struct udevice *dev, int of_offset)
{
	dev->node = offset_to_ofnode(of_offset);
}

static inline bool dev_has_of_node(struct udevice *dev)
{
	return ofnode_valid(dev->node);
}

/**
 * struct udevice_id - Lists the compatible strings supported by a driver
 * @compatible: Compatible string
 * @data: Data for this compatible string
 */
struct udevice_id {
	const char *compatible;
	ulong data;
};

#if CONFIG_IS_ENABLED(OF_CONTROL)
#define of_match_ptr(_ptr)	(_ptr)
#else
#define of_match_ptr(_ptr)	NULL
#endif /* CONFIG_IS_ENABLED(OF_CONTROL) */

/**
 * struct driver - A driver for a feature or peripheral
 *
 * This holds methods for setting up a new device, and also removing it.
 * The device needs information to set itself up - this is provided either
 * by platdata or a device tree node (which we find by looking up
 * matching compatible strings with of_match).
 *
 * Drivers all belong to a uclass, representing a class of devices of the
 * same type. Common elements of the drivers can be implemented in the uclass,
 * or the uclass can provide a consistent interface to the drivers within
 * it.
 *
 * @name: Device name
 * @id: Identifies the uclass we belong to
 * @of_match: List of compatible strings to match, and any identifying data
 * for each.
 * @bind: Called to bind a device to its driver
 * @probe: Called to probe a device, i.e. activate it
 * @remove: Called to remove a device, i.e. de-activate it
 * @unbind: Called to unbind a device from its driver
 * @ofdata_to_platdata: Called before probe to decode device tree data
 * @child_post_bind: Called after a new child has been bound
 * @child_pre_probe: Called before a child device is probed. The device has
 * memory allocated but it has not yet been probed.
 * @child_post_remove: Called after a child device is removed. The device
 * has memory allocated but its device_remove() method has been called.
 * @priv_auto_alloc_size: If non-zero this is the size of the private data
 * to be allocated in the device's ->priv pointer. If zero, then the driver
 * is responsible for allocating any data required.
 * @platdata_auto_alloc_size: If non-zero this is the size of the
 * platform data to be allocated in the device's ->platdata pointer.
 * This is typically only useful for device-tree-aware drivers (those with
 * an of_match), since drivers which use platdata will have the data
 * provided in the U_BOOT_DEVICE() instantiation.
 * @per_child_auto_alloc_size: Each device can hold private data owned by
 * its parent. If required this will be automatically allocated if this
 * value is non-zero.
 * @per_child_platdata_auto_alloc_size: A bus likes to store information about
 * its children. If non-zero this is the size of this data, to be allocated
 * in the child's parent_platdata pointer.
 * @ops: Driver-specific operations. This is typically a list of function
 * pointers defined by the driver, to implement driver functions required by
 * the uclass.
 * @flags: driver flags - see DM_FLAGS_...
 */
struct driver {
	char *name;
	enum uclass_id id;
	const struct udevice_id *of_match;
	int (*bind)(struct udevice *dev);
	int (*probe)(struct udevice *dev);
	int (*remove)(struct udevice *dev);
	int (*unbind)(struct udevice *dev);
	int (*ofdata_to_platdata)(struct udevice *dev);
	int (*child_post_bind)(struct udevice *dev);
	int (*child_pre_probe)(struct udevice *dev);
	int (*child_post_remove)(struct udevice *dev);
	int priv_auto_alloc_size;
	int platdata_auto_alloc_size;
	int per_child_auto_alloc_size;
	int per_child_platdata_auto_alloc_size;
	const void *ops;	/* driver-specific operations */
	uint32_t flags;
};

/* Declare a new U-Boot driver */
#define U_BOOT_DRIVER(__name)						\
	ll_entry_declare(struct driver, __name, driver)

/* Get a pointer to a given driver */
#define DM_GET_DRIVER(__name)						\
	ll_entry_get(struct driver, __name, driver)

/**
 * dev_get_platdata() - Get the platform data for a device
 *
 * This checks that dev is not NULL, but no other checks for now
 *
 * @dev		Device to check
 * @return platform data, or NULL if none
 */
void *dev_get_platdata(const struct udevice *dev);

/**
 * dev_get_parent_platdata() - Get the parent platform data for a device
 *
 * This checks that dev is not NULL, but no other checks for now
 *
 * @dev		Device to check
 * @return parent's platform data, or NULL if none
 */
void *dev_get_parent_platdata(const struct udevice *dev);

/**
 * dev_get_uclass_platdata() - Get the uclass platform data for a device
 *
 * This checks that dev is not NULL, but no other checks for now
 *
 * @dev		Device to check
 * @return uclass's platform data, or NULL if none
 */
void *dev_get_uclass_platdata(const struct udevice *dev);

/**
 * dev_get_priv() - Get the private data for a device
 *
 * This checks that dev is not NULL, but no other checks for now
 *
 * @dev		Device to check
 * @return private data, or NULL if none
 */
void *dev_get_priv(const struct udevice *dev);

/**
 * dev_get_parent_priv() - Get the parent private data for a device
 *
 * The parent private data is data stored in the device but owned by the
 * parent. For example, a USB device may have parent data which contains
 * information about how to talk to the device over USB.
 *
 * This checks that dev is not NULL, but no other checks for now
 *
 * @dev		Device to check
 * @return parent data, or NULL if none
 */
void *dev_get_parent_priv(const struct udevice *dev);

/**
 * dev_get_uclass_priv() - Get the private uclass data for a device
 *
 * This checks that dev is not NULL, but no other checks for now
 *
 * @dev		Device to check
 * @return private uclass data for this device, or NULL if none
 */
void *dev_get_uclass_priv(const struct udevice *dev);

/**
 * struct dev_get_parent() - Get the parent of a device
 *
 * @child:	Child to check
 * @return parent of child, or NULL if this is the root device
 */
struct udevice *dev_get_parent(const struct udevice *child);

/**
 * dev_get_driver_data() - get the driver data used to bind a device
 *
 * When a device is bound using a device tree node, it matches a
 * particular compatible string in struct udevice_id. This function
 * returns the associated data value for that compatible string. This is
 * the 'data' field in struct udevice_id.
 *
 * As an example, consider this structure:
 * static const struct udevice_id tegra_i2c_ids[] = {
 *	{ .compatible = "nvidia,tegra114-i2c", .data = TYPE_114 },
 *	{ .compatible = "nvidia,tegra20-i2c", .data = TYPE_STD },
 *	{ .compatible = "nvidia,tegra20-i2c-dvc", .data = TYPE_DVC },
 *	{ }
 * };
 *
 * When driver model finds a driver for this it will store the 'data' value
 * corresponding to the compatible string it matches. This function returns
 * that value. This allows the driver to handle several variants of a device.
 *
 * For USB devices, this is the driver_info field in struct usb_device_id.
 *
 * @dev:	Device to check
 * @return driver data (0 if none is provided)
 */
ulong dev_get_driver_data(const struct udevice *dev);

/**
 * dev_get_driver_ops() - get the device's driver's operations
 *
 * This checks that dev is not NULL, and returns the pointer to device's
 * driver's operations.
 *
 * @dev:	Device to check
 * @return void pointer to driver's operations or NULL for NULL-dev or NULL-ops
 */
const void *dev_get_driver_ops(const struct udevice *dev);

/**
 * device_get_uclass_id() - return the uclass ID of a device
 *
 * @dev:	Device to check
 * @return uclass ID for the device
 */
enum uclass_id device_get_uclass_id(const struct udevice *dev);

/**
 * dev_get_uclass_name() - return the uclass name of a device
 *
 * This checks that dev is not NULL.
 *
 * @dev:	Device to check
 * @return  pointer to the uclass name for the device
 */
const char *dev_get_uclass_name(const struct udevice *dev);

/**
 * device_get_child() - Get the child of a device by index
 *
 * Returns the numbered child, 0 being the first. This does not use
 * sequence numbers, only the natural order.
 *
 * @dev:	Parent device to check
 * @index:	Child index
 * @devp:	Returns pointer to device
 * @return 0 if OK, -ENODEV if no such device, other error if the device fails
 *	   to probe
 */
int device_get_child(const struct udevice *parent, int index,
		     struct udevice **devp);

/**
 * device_get_child_count() - Get the available child count of a device
 *
 * Returns the number of children to a device.
 *
 * @parent:	Parent device to check
 */
int device_get_child_count(const struct udevice *parent);

/**
 * device_find_child_by_seq() - Find a child device based on a sequence
 *
 * This searches for a device with the given seq or req_seq.
 *
 * For seq, if an active device has this sequence it will be returned.
 * If there is no such device then this will return -ENODEV.
 *
 * For req_seq, if a device (whether activated or not) has this req_seq
 * value, that device will be returned. This is a strong indication that
 * the device will receive that sequence when activated.
 *
 * @parent: Parent device
 * @seq_or_req_seq: Sequence number to find (0=first)
 * @find_req_seq: true to find req_seq, false to find seq
 * @devp: Returns pointer to device (there is only one per for each seq).
 * Set to NULL if none is found
 * @return 0 if OK, -ve on error
 */
int device_find_child_by_seq(const struct udevice *parent, int seq_or_req_seq,
			     bool find_req_seq, struct udevice **devp);

/**
 * device_get_child_by_seq() - Get a child device based on a sequence
 *
 * If an active device has this sequence it will be returned. If there is no
 * such device then this will check for a device that is requesting this
 * sequence.
 *
 * The device is probed to activate it ready for use.
 *
 * @parent: Parent device
 * @seq: Sequence number to find (0=first)
 * @devp: Returns pointer to device (there is only one per for each seq)
 * Set to NULL if none is found
 * @return 0 if OK, -ve on error
 */
int device_get_child_by_seq(const struct udevice *parent, int seq,
			    struct udevice **devp);

/**
 * device_find_child_by_of_offset() - Find a child device based on FDT offset
 *
 * Locates a child device by its device tree offset.
 *
 * @parent: Parent device
 * @of_offset: Device tree offset to find
 * @devp: Returns pointer to device if found, otherwise this is set to NULL
 * @return 0 if OK, -ve on error
 */
int device_find_child_by_of_offset(const struct udevice *parent, int of_offset,
				   struct udevice **devp);

/**
 * device_get_child_by_of_offset() - Get a child device based on FDT offset
 *
 * Locates a child device by its device tree offset.
 *
 * The device is probed to activate it ready for use.
 *
 * @parent: Parent device
 * @of_offset: Device tree offset to find
 * @devp: Returns pointer to device if found, otherwise this is set to NULL
 * @return 0 if OK, -ve on error
 */
int device_get_child_by_of_offset(const struct udevice *parent, int of_offset,
				  struct udevice **devp);

/**
 * device_find_global_by_ofnode() - Get a device based on ofnode
 *
 * Locates a device by its device tree ofnode, searching globally throughout
 * the all driver model devices.
 *
 * The device is NOT probed
 *
 * @node: Device tree ofnode to find
 * @devp: Returns pointer to device if found, otherwise this is set to NULL
 * @return 0 if OK, -ve on error
 */

int device_find_global_by_ofnode(ofnode node, struct udevice **devp);

/**
 * device_get_global_by_ofnode() - Get a device based on ofnode
 *
 * Locates a device by its device tree ofnode, searching globally throughout
 * the all driver model devices.
 *
 * The device is probed to activate it ready for use.
 *
 * @node: Device tree ofnode to find
 * @devp: Returns pointer to device if found, otherwise this is set to NULL
 * @return 0 if OK, -ve on error
 */
int device_get_global_by_ofnode(ofnode node, struct udevice **devp);

/**
 * device_find_first_child() - Find the first child of a device
 *
 * @parent: Parent device to search
 * @devp: Returns first child device, or NULL if none
 * @return 0
 */
int device_find_first_child(const struct udevice *parent,
			    struct udevice **devp);

/**
 * device_find_next_child() - Find the next child of a device
 *
 * @devp: Pointer to previous child device on entry. Returns pointer to next
 *		child device, or NULL if none
 * @return 0
 */
int device_find_next_child(struct udevice **devp);

/**
 * device_find_first_inactive_child() - Find the first inactive child
 *
 * This is used to locate an existing child of a device which is of a given
 * uclass.
 *
 * The device is NOT probed
 *
 * @parent:	Parent device to search
 * @uclass_id:	Uclass to look for
 * @devp:	Returns device found, if any
 * @return 0 if found, else -ENODEV
 */
int device_find_first_inactive_child(const struct udevice *parent,
				     enum uclass_id uclass_id,
				     struct udevice **devp);

/**
 * device_find_first_child_by_uclass() - Find the first child of a device in uc
 *
 * @parent: Parent device to search
 * @uclass_id:	Uclass to look for
 * @devp: Returns first child device in that uclass, if any
 * @return 0 if found, else -ENODEV
 */
int device_find_first_child_by_uclass(const struct udevice *parent,
				      enum uclass_id uclass_id,
				      struct udevice **devp);

/**
 * device_find_child_by_name() - Find a child by device name
 *
 * @parent:	Parent device to search
 * @name:	Name to look for
 * @devp:	Returns device found, if any
 * @return 0 if found, else -ENODEV
 */
int device_find_child_by_name(const struct udevice *parent, const char *name,
			      struct udevice **devp);

/**
 * device_first_child_ofdata_err() - Find the first child and reads its platdata
 *
 * The ofdata_to_platdata() method is called on the child before it is returned,
 * but the child is not probed.
 *
 * @parent: Parent to check
 * @devp: Returns child that was found, if any
 * @return 0 on success, -ENODEV if no children, other -ve on error
 */
int device_first_child_ofdata_err(struct udevice *parent,
				  struct udevice **devp);

/*
 * device_next_child_ofdata_err() - Find the next child and read its platdata
 *
 * The ofdata_to_platdata() method is called on the child before it is returned,
 * but the child is not probed.
 *
 * @devp: On entry, points to the previous child; on exit returns the child that
 *	was found, if any
 * @return 0 on success, -ENODEV if no children, other -ve on error
 */
int device_next_child_ofdata_err(struct udevice **devp);

/**
 * device_first_child_err() - Get the first child of a device
 *
 * The device returned is probed if necessary, and ready for use
 *
 * @parent:	Parent device to search
 * @devp:	Returns device found, if any
 * @return 0 if found, -ENODEV if not, -ve error if device failed to probe
 */
int device_first_child_err(struct udevice *parent, struct udevice **devp);

/**
 * device_next_child_err() - Get the next child of a parent device
 *
 * The device returned is probed if necessary, and ready for use
 *
 * @devp: On entry, pointer to device to lookup. On exit, returns pointer
 * to the next sibling if no error occurred
 * @return 0 if found, -ENODEV if not, -ve error if device failed to probe
 */
int device_next_child_err(struct udevice **devp);

/**
 * device_has_children() - check if a device has any children
 *
 * @dev:	Device to check
 * @return true if the device has one or more children
 */
bool device_has_children(const struct udevice *dev);

/**
 * device_has_active_children() - check if a device has any active children
 *
 * @dev:	Device to check
 * @return true if the device has one or more children and at least one of
 * them is active (probed).
 */
bool device_has_active_children(const struct udevice *dev);

/**
 * device_is_last_sibling() - check if a device is the last sibling
 *
 * This function can be useful for display purposes, when special action needs
 * to be taken when displaying the last sibling. This can happen when a tree
 * view of devices is being displayed.
 *
 * @dev:	Device to check
 * @return true if there are no more siblings after this one - i.e. is it
 * last in the list.
 */
bool device_is_last_sibling(const struct udevice *dev);

/**
 * device_set_name() - set the name of a device
 *
 * This must be called in the device's bind() method and no later. Normally
 * this is unnecessary but for probed devices which don't get a useful name
 * this function can be helpful.
 *
 * The name is allocated and will be freed automatically when the device is
 * unbound.
 *
 * @dev:	Device to update
 * @name:	New name (this string is allocated new memory and attached to
 *		the device)
 * @return 0 if OK, -ENOMEM if there is not enough memory to allocate the
 * string
 */
int device_set_name(struct udevice *dev, const char *name);

/**
 * device_set_name_alloced() - note that a device name is allocated
 *
 * This sets the DM_FLAG_NAME_ALLOCED flag for the device, so that when it is
 * unbound the name will be freed. This avoids memory leaks.
 *
 * @dev:	Device to update
 */
void device_set_name_alloced(struct udevice *dev);

/**
 * device_is_compatible() - check if the device is compatible with the compat
 *
 * This allows to check whether the device is comaptible with the compat.
 *
 * @dev:	udevice pointer for which compatible needs to be verified.
 * @compat:	Compatible string which needs to verified in the given
 *		device
 * @return true if OK, false if the compatible is not found
 */
bool device_is_compatible(const struct udevice *dev, const char *compat);

/**
 * of_machine_is_compatible() - check if the machine is compatible with
 *				the compat
 *
 * This allows to check whether the machine is comaptible with the compat.
 *
 * @compat:	Compatible string which needs to verified
 * @return true if OK, false if the compatible is not found
 */
bool of_machine_is_compatible(const char *compat);

/**
 * dev_disable_by_path() - Disable a device given its device tree path
 *
 * @path:	The device tree path identifying the device to be disabled
 * @return 0 on success, -ve on error
 */
int dev_disable_by_path(const char *path);

/**
 * dev_enable_by_path() - Enable a device given its device tree path
 *
 * @path:	The device tree path identifying the device to be enabled
 * @return 0 on success, -ve on error
 */
int dev_enable_by_path(const char *path);

/**
 * device_is_on_pci_bus - Test if a device is on a PCI bus
 *
 * @dev:	device to test
 * @return:	true if it is on a PCI bus, false otherwise
 */
static inline bool device_is_on_pci_bus(const struct udevice *dev)
{
	return device_get_uclass_id(dev->parent) == UCLASS_PCI;
}

/**
 * device_foreach_child_safe() - iterate through child devices safely
 *
 * This allows the @pos child to be removed in the loop if required.
 *
 * @pos: struct udevice * for the current device
 * @next: struct udevice * for the next device
 * @parent: parent device to scan
 */
#define device_foreach_child_safe(pos, next, parent)	\
	list_for_each_entry_safe(pos, next, &parent->child_head, sibling_node)

/**
 * device_foreach_child() - iterate through child devices
 *
 * @pos: struct udevice * for the current device
 * @parent: parent device to scan
 */
#define device_foreach_child(pos, parent)	\
	list_for_each_entry(pos, &parent->child_head, sibling_node)

/**
 * device_foreach_child_ofdata_to_platdata() - iterate through children
 *
 * This stops when it gets an error, with @pos set to the device that failed to
 * read ofdata.

 * This creates a for() loop which works through the available children of
 * a device in order from start to end. Device ofdata is read by calling
 * device_ofdata_to_platdata() on each one. The devices are not probed.
 *
 * @pos: struct udevice * for the current device
 * @parent: parent device to scan
 */
#define device_foreach_child_ofdata_to_platdata(pos, parent)	\
	for (int _ret = device_first_child_ofdata_err(parent, &dev); !_ret; \
	     _ret = device_next_child_ofdata_err(&dev))

/**
 * device_foreach_child_probe() - iterate through children, probing them
 *
 * This creates a for() loop which works through the available children of
 * a device in order from start to end. Devices are probed if necessary,
 * and ready for use.
 *
 * This stops when it gets an error, with @pos set to the device that failed to
 * probe
 *
 * @pos: struct udevice * for the current device
 * @parent: parent device to scan
 */
#define device_foreach_child_probe(pos, parent)	\
	for (int _ret = device_first_child_err(parent, &dev); !_ret; \
	     _ret = device_next_child_err(&dev))

/**
 * dm_scan_fdt_dev() - Bind child device in a the device tree
 *
 * This handles device which have sub-nodes in the device tree. It scans all
 * sub-nodes and binds drivers for each node where a driver can be found.
 *
 * If this is called prior to relocation, only pre-relocation devices will be
 * bound (those marked with u-boot,dm-pre-reloc in the device tree, or where
 * the driver has the DM_FLAG_PRE_RELOC flag set). Otherwise, all devices will
 * be bound.
 *
 * @dev:	Device to scan
 * @return 0 if OK, -ve on error
 */
int dm_scan_fdt_dev(struct udevice *dev);

/*
 * REVISIT:
 * remove the following after resolving conflicts with <linux/compat.h>
 */
#ifdef dev_dbg
#undef dev_dbg
#endif
#ifdef dev_vdbg
#undef dev_vdbg
#endif
#ifdef dev_info
#undef dev_info
#endif
#ifdef dev_err
#undef dev_err
#endif
#ifdef dev_warn
#undef dev_warn
#endif

/*
 * REVISIT:
 * print device name like Linux
 */
#define dev_printk(dev, fmt, ...)				\
({								\
	printk(fmt, ##__VA_ARGS__);				\
})

#define __dev_printk(level, dev, fmt, ...)			\
({								\
	if (level < CONFIG_VAL(LOGLEVEL))			\
		dev_printk(dev, fmt, ##__VA_ARGS__);		\
})

#define dev_emerg(dev, fmt, ...) \
	__dev_printk(0, dev, fmt, ##__VA_ARGS__)
#define dev_alert(dev, fmt, ...) \
	__dev_printk(1, dev, fmt, ##__VA_ARGS__)
#define dev_crit(dev, fmt, ...) \
	__dev_printk(2, dev, fmt, ##__VA_ARGS__)
#define dev_err(dev, fmt, ...) \
	__dev_printk(3, dev, fmt, ##__VA_ARGS__)
#define dev_warn(dev, fmt, ...) \
	__dev_printk(4, dev, fmt, ##__VA_ARGS__)
#define dev_notice(dev, fmt, ...) \
	__dev_printk(5, dev, fmt, ##__VA_ARGS__)
#define dev_info(dev, fmt, ...) \
	__dev_printk(6, dev, fmt, ##__VA_ARGS__)

#ifdef DEBUG
#define dev_dbg(dev, fmt, ...) \
	__dev_printk(7, dev, fmt, ##__VA_ARGS__)
#else
#define dev_dbg(dev, fmt, ...)					\
({								\
	if (0)							\
		__dev_printk(7, dev, fmt, ##__VA_ARGS__);	\
})
#endif

#ifdef VERBOSE_DEBUG
#define dev_vdbg	dev_dbg
#else
#define dev_vdbg(dev, fmt, ...)					\
({								\
	if (0)							\
		__dev_printk(7, dev, fmt, ##__VA_ARGS__);	\
})
#endif

#endif