1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Copyright (c) 2016, NVIDIA CORPORATION.
4 */
5
6#ifndef _RESET_H
7#define _RESET_H
8
9#include <dm/ofnode.h>
10#include <linux/err.h>
11
12/**
13 * A reset is a hardware signal indicating that a HW module (or IP block, or
14 * sometimes an entire off-CPU chip) reset all of its internal state to some
15 * known-good initial state. Drivers will often reset HW modules when they
16 * begin execution to ensure that hardware correctly responds to all requests,
17 * or in response to some error condition. Reset signals are often controlled
18 * externally to the HW module being reset, by an entity this API calls a reset
19 * controller. This API provides a standard means for drivers to request that
20 * reset controllers set or clear reset signals.
21 *
22 * A driver that implements UCLASS_RESET is a reset controller or provider. A
23 * controller will often implement multiple separate reset signals, since the
24 * hardware it manages often has this capability. reset-uclass.h describes the
25 * interface which reset controllers must implement.
26 *
27 * Reset consumers/clients are the HW modules affected by reset signals. This
28 * header file describes the API used by drivers for those HW modules.
29 */
30
31struct udevice;
32
33/**
34 * struct reset_ctl - A handle to (allowing control of) a single reset signal.
35 *
36 * Clients provide storage for reset control handles. The content of the
37 * structure is managed solely by the reset API and reset drivers. A reset
38 * control struct is initialized by "get"ing the reset control struct. The
39 * reset control struct is passed to all other reset APIs to identify which
40 * reset signal to operate upon.
41 *
42 * @dev: The device which implements the reset signal.
43 * @id: The reset signal ID within the provider.
44 * @data: An optional data field for scenarios where a single integer ID is not
45 *	  sufficient. If used, it can be populated through an .of_xlate op and
46 *	  processed during the various reset ops.
47 * @polarity: An optional polarity field for drivers that support
48 *	  different reset polarities.
49 *
50 * Should additional information to identify and configure any reset signal
51 * for any provider be required in the future, the struct could be expanded to
52 * either (a) add more fields to allow reset providers to store additional
53 * information, or (b) replace the id field with an opaque pointer, which the
54 * provider would dynamically allocated during its .of_xlate op, and process
55 * during is .request op. This may require the addition of an extra op to clean
56 * up the allocation.
57 */
58struct reset_ctl {
59	struct udevice *dev;
60	/*
61	 * Written by of_xlate. In the future, we might add more fields here.
62	 */
63	unsigned long id;
64	unsigned long data;
65	unsigned long polarity;
66};
67
68/**
69 * struct reset_ctl_bulk - A handle to (allowing control of) a bulk of reset
70 * signals.
71 *
72 * Clients provide storage for the reset control bulk. The content of the
73 * structure is managed solely by the reset API. A reset control bulk struct is
74 * initialized by "get"ing the reset control bulk struct.
75 * The reset control bulk struct is passed to all other bulk reset APIs to apply
76 * the API to all the reset signals in the bulk struct.
77 *
78 * @resets: An array of reset signal handles handles.
79 * @count: The number of reset signal handles in the reset array.
80 */
81struct reset_ctl_bulk {
82	struct reset_ctl *resets;
83	unsigned int count;
84};
85
86#if CONFIG_IS_ENABLED(DM_RESET)
87
88/**
89 * devm_reset_control_get - resource managed reset_get_by_name()
90 * @dev: device to be reset by the controller
91 * @id: reset line name
92 *
93 * Managed reset_get_by_name(). For reset controllers returned
94 * from this function, reset_free() is called automatically on driver
95 * detach.
96 *
97 * Returns a struct reset_ctl or IS_ERR() condition containing errno.
98 */
99struct reset_ctl *devm_reset_control_get(struct udevice *dev, const char *id);
100
101/**
102 * devm_reset_control_get_optional - resource managed reset_get_by_name() that
103 *                                   can fail
104 * @dev:	The client device.
105 * @id:		reset line name
106 *
107 * Managed reset_get_by_name(). For reset controllers returned
108 * from this function, reset_free() is called automatically on driver
109 * detach.
110 *
111 * Returns a struct reset_ctl or a dummy reset controller if it failed.
112 */
113struct reset_ctl *devm_reset_control_get_optional(struct udevice *dev,
114						  const char *id);
115
116/**
117 * devm_reset_control_get - resource managed reset_get_by_index()
118 * @dev:	The client device.
119 * @index:	The index of the reset signal to request, within the client's
120 *		list of reset signals.
121 *
122 * Managed reset_get_by_index(). For reset controllers returned
123 * from this function, reset_free() is called automatically on driver
124 * detach.
125 *
126 * Returns a struct reset_ctl or IS_ERR() condition containing errno.
127 */
128struct reset_ctl *devm_reset_control_get_by_index(struct udevice *dev,
129						  int index);
130
131/**
132 * devm_reset_bulk_get - resource managed reset_get_bulk()
133 * @dev: device to be reset by the controller
134 *
135 * Managed reset_get_bulk(). For reset controllers returned
136 * from this function, reset_free() is called automatically on driver
137 * detach.
138 *
139 * Returns a struct reset_ctl or IS_ERR() condition containing errno.
140 */
141struct reset_ctl_bulk *devm_reset_bulk_get(struct udevice *dev);
142
143/**
144 * devm_reset_bulk_get_optional - resource managed reset_get_bulk() that
145 *                                can fail
146 * @dev:	The client device.
147 *
148 * Managed reset_get_bulk(). For reset controllers returned
149 * from this function, reset_free() is called automatically on driver
150 * detach.
151 *
152 * Returns a struct reset_ctl or NULL if it failed.
153 */
154struct reset_ctl_bulk *devm_reset_bulk_get_optional(struct udevice *dev);
155
156/**
157 * devm_reset_bulk_get_by_node - resource managed reset_get_bulk()
158 * @dev: device to be reset by the controller
159 * @node: ofnode where the "resets" property is. Usually a sub-node of
160 *        the dev's node.
161 *
162 * see devm_reset_bulk_get()
163 */
164struct reset_ctl_bulk *devm_reset_bulk_get_by_node(struct udevice *dev,
165						   ofnode node);
166
167/**
168 * devm_reset_bulk_get_optional_by_node - resource managed reset_get_bulk()
169 *                                        that can fail
170 * @dev: device to be reset by the controller
171 * @node: ofnode where the "resets" property is. Usually a sub-node of
172 *        the dev's node.
173 *
174 * see devm_reset_bulk_get_optional()
175 */
176struct reset_ctl_bulk *devm_reset_bulk_get_optional_by_node(struct udevice *dev,
177							    ofnode node);
178
179/**
180 * reset_get_by_index - Get/request a reset signal by integer index.
181 *
182 * This looks up and requests a reset signal. The index is relative to the
183 * client device; each device is assumed to have n reset signals associated
184 * with it somehow, and this function finds and requests one of them. The
185 * mapping of client device reset signal indices to provider reset signals may
186 * be via device-tree properties, board-provided mapping tables, or some other
187 * mechanism.
188 *
189 * @dev:	The client device.
190 * @index:	The index of the reset signal to request, within the client's
191 *		list of reset signals.
192 * @reset_ctl	A pointer to a reset control struct to initialize.
193 * Return: 0 if OK, or a negative error code.
194 */
195int reset_get_by_index(struct udevice *dev, int index,
196		       struct reset_ctl *reset_ctl);
197
198/**
199 * reset_get_by_index_nodev - Get/request a reset signal by integer index
200 * without a device.
201 *
202 * This is a version of reset_get_by_index() that does not use a device.
203 *
204 * @node:	The client ofnode.
205 * @index:	The index of the reset signal to request, within the client's
206 *		list of reset signals.
207 * @reset_ctl	A pointer to a reset control struct to initialize.
208 * Return: 0 if OK, or a negative error code.
209 */
210int reset_get_by_index_nodev(ofnode node, int index,
211			     struct reset_ctl *reset_ctl);
212
213/**
214 * reset_get_bulk - Get/request all reset signals of a device.
215 *
216 * This looks up and requests all reset signals of the client device; each
217 * device is assumed to have n reset signals associated with it somehow,
218 * and this function finds and requests all of them in a separate structure.
219 * The mapping of client device reset signals indices to provider reset signals
220 * may be via device-tree properties, board-provided mapping tables, or some
221 * other mechanism.
222 *
223 * @dev:	The client device.
224 * @bulk	A pointer to a reset control bulk struct to initialize.
225 * Return: 0 if OK, or a negative error code.
226 */
227int reset_get_bulk(struct udevice *dev, struct reset_ctl_bulk *bulk);
228
229/**
230 * reset_get_by_name - Get/request a reset signal by name.
231 *
232 * This looks up and requests a reset signal. The name is relative to the
233 * client device; each device is assumed to have n reset signals associated
234 * with it somehow, and this function finds and requests one of them. The
235 * mapping of client device reset signal names to provider reset signal may be
236 * via device-tree properties, board-provided mapping tables, or some other
237 * mechanism.
238 *
239 * @dev:	The client device.
240 * @name:	The name of the reset signal to request, within the client's
241 *		list of reset signals, or NULL to request the first reset
242 *		signal in the list.
243 * @reset_ctl:	A pointer to a reset control struct to initialize.
244 * Return: 0 if OK, or a negative error code.
245 */
246int reset_get_by_name(struct udevice *dev, const char *name,
247		      struct reset_ctl *reset_ctl);
248
249/**
250 * reset_request - Request a reset signal.
251 *
252 * @reset_ctl:	A reset control struct.
253 *
254 * Return: 0 if OK, or a negative error code.
255 */
256int reset_request(struct reset_ctl *reset_ctl);
257
258/**
259 * reset_free - Free a previously requested reset signal.
260 *
261 * @reset_ctl:	A reset control struct that was previously successfully
262 *		requested by reset_get_by_*().
263 * Return: 0 if OK, or a negative error code.
264 */
265int reset_free(struct reset_ctl *reset_ctl);
266
267/**
268 * reset_assert - Assert a reset signal.
269 *
270 * This function will assert the specified reset signal, thus resetting the
271 * affected HW module(s). Depending on the reset controller hardware, the reset
272 * signal will either stay asserted until reset_deassert() is called, or the
273 * hardware may autonomously clear the reset signal itself.
274 *
275 * @reset_ctl:	A reset control struct that was previously successfully
276 *		requested by reset_get_by_*().
277 * Return: 0 if OK, or a negative error code.
278 */
279int reset_assert(struct reset_ctl *reset_ctl);
280
281/**
282 * reset_assert_bulk - Assert all reset signals in a reset control bulk struct.
283 *
284 * This function will assert the specified reset signals in a reset control
285 * bulk struct, thus resetting the affected HW module(s). Depending on the
286 * reset controller hardware, the reset signals will either stay asserted
287 * until reset_deassert_bulk() is called, or the hardware may autonomously
288 * clear the reset signals itself.
289 *
290 * @bulk:	A reset control bulk struct that was previously successfully
291 *		requested by reset_get_bulk().
292 * Return: 0 if OK, or a negative error code.
293 */
294int reset_assert_bulk(struct reset_ctl_bulk *bulk);
295
296/**
297 * reset_deassert - Deassert a reset signal.
298 *
299 * This function will deassert the specified reset signal, thus releasing the
300 * affected HW modules() from reset, and allowing them to continue normal
301 * operation.
302 *
303 * @reset_ctl:	A reset control struct that was previously successfully
304 *		requested by reset_get_by_*().
305 * Return: 0 if OK, or a negative error code.
306 */
307int reset_deassert(struct reset_ctl *reset_ctl);
308
309/**
310 * reset_deassert_bulk - Deassert all reset signals in a reset control bulk
311 * struct.
312 *
313 * This function will deassert the specified reset signals in a reset control
314 * bulk struct, thus releasing the affected HW modules() from reset, and
315 * allowing them to continue normal operation.
316 *
317 * @bulk:	A reset control bulk struct that was previously successfully
318 *		requested by reset_get_bulk().
319 * Return: 0 if OK, or a negative error code.
320 */
321int reset_deassert_bulk(struct reset_ctl_bulk *bulk);
322
323/**
324 * rst_status - Check reset signal status.
325 *
326 * @reset_ctl:	The reset signal to check.
327 * Return: 0 if deasserted, positive if asserted, or a negative
328 *           error code.
329 */
330int reset_status(struct reset_ctl *reset_ctl);
331
332/**
333 * reset_release_all - Assert/Free an array of previously requested resets.
334 *
335 * For each reset contained in the reset array, this function will check if
336 * reset has been previously requested and then will assert and free it.
337 *
338 * @reset_ctl:	A reset struct array that was previously successfully
339 *		requested by reset_get_by_*().
340 * @count	Number of reset contained in the array
341 * Return: 0 if OK, or a negative error code.
342 */
343int reset_release_all(struct reset_ctl *reset_ctl, int count);
344
345/**
346 * reset_release_bulk - Assert/Free an array of previously requested reset
347 * signals in a reset control bulk struct.
348 *
349 * For each reset contained in the reset control bulk struct, this function
350 * will check if reset has been previously requested and then will assert
351 * and free it.
352 *
353 * @bulk:	A reset control bulk struct that was previously successfully
354 *		requested by reset_get_bulk().
355 * Return: 0 if OK, or a negative error code.
356 */
357static inline int reset_release_bulk(struct reset_ctl_bulk *bulk)
358{
359	return reset_release_all(bulk->resets, bulk->count);
360}
361
362#else
363static inline struct reset_ctl *devm_reset_control_get(struct udevice *dev,
364						       const char *id)
365{
366	return ERR_PTR(-ENOTSUPP);
367}
368
369static inline struct reset_ctl *devm_reset_control_get_optional(struct udevice *dev,
370								const char *id)
371{
372	return NULL;
373}
374
375static inline struct reset_ctl *devm_reset_control_get_by_index(struct udevice *dev,
376								int index)
377{
378	return ERR_PTR(-ENOTSUPP);
379}
380
381static inline struct reset_ctl_bulk *devm_reset_bulk_get(struct udevice *dev)
382{
383	return ERR_PTR(-ENOTSUPP);
384}
385
386static inline struct reset_ctl_bulk *devm_reset_bulk_get_optional(struct udevice *dev)
387{
388	return NULL;
389}
390
391static inline struct reset_ctl_bulk *devm_reset_bulk_get_by_node(struct udevice *dev,
392								 ofnode node)
393{
394	return ERR_PTR(-ENOTSUPP);
395}
396
397static inline struct reset_ctl_bulk *devm_reset_bulk_get_optional_by_node(struct udevice *dev,
398									  ofnode node)
399{
400	return NULL;
401}
402
403static inline int reset_get_by_index(struct udevice *dev, int index,
404				     struct reset_ctl *reset_ctl)
405{
406	return -ENOTSUPP;
407}
408
409static inline int reset_get_bulk(struct udevice *dev,
410				 struct reset_ctl_bulk *bulk)
411{
412	return -ENOTSUPP;
413}
414
415static inline int reset_get_by_name(struct udevice *dev, const char *name,
416				    struct reset_ctl *reset_ctl)
417{
418	return -ENOTSUPP;
419}
420
421static inline int reset_free(struct reset_ctl *reset_ctl)
422{
423	return 0;
424}
425
426static inline int reset_assert(struct reset_ctl *reset_ctl)
427{
428	return 0;
429}
430
431static inline int reset_assert_bulk(struct reset_ctl_bulk *bulk)
432{
433	return 0;
434}
435
436static inline int reset_deassert(struct reset_ctl *reset_ctl)
437{
438	return 0;
439}
440
441static inline int reset_deassert_bulk(struct reset_ctl_bulk *bulk)
442{
443	return 0;
444}
445
446static inline int reset_status(struct reset_ctl *reset_ctl)
447{
448	return -ENOTSUPP;
449}
450
451static inline int reset_release_all(struct reset_ctl *reset_ctl, int count)
452{
453	return 0;
454}
455
456static inline int reset_release_bulk(struct reset_ctl_bulk *bulk)
457{
458	return 0;
459}
460#endif
461
462/**
463 * reset_valid() - check if reset is valid
464 *
465 * @reset_ctl:		the reset to check
466 * Return: TRUE if valid, or FALSE
467 */
468static inline bool reset_valid(struct reset_ctl *reset_ctl)
469{
470	return !!reset_ctl->dev;
471}
472
473#endif
474